Preparation method of self-friction long-lasting static high-temperature air filtration needle-punched composite material

Abstract

The invention belongs to the technical field of air filtration composite materials and discloses a method for preparing a self-friction long-lasting electret high-temperature air filtration needle-punched composite material. The method comprises the following steps: opening, mixing, combing and laying polytetrafluoroethylene / electret composite short fibers, polyphenylene sulfide / electret composite short fibers, polyimide / electret composite short fibers, electret short fibers and high-temperature resistant hot-melt short fibers; after the opening, mixing, combing and laying are completed, the fibers are further subjected to needle punching and liquid friction electret treatment; the needle-punched nonwoven material subjected to liquid friction electret treatment and drying temperature is composited with a polytetrafluoroethylene microporous membrane to obtain a high-temperature resistant air filtration needle-punched filter material with a long-lasting electrostatic load.

Description

Technical Field

[0001] The invention belongs to the technical field of air filtration composite materials, and in particular relates to a preparation method of a self-friction long-lasting electret high-temperature air filtration needle-punched composite material. Background Art

[0002] In recent years, the challenge of air pollution control has become increasingly severe, and national and local governments at all levels have increasingly stringent requirements for air emission cleanliness. Currently, the most commonly used materials in high-temperature air filtration are composite nonwovens made by needle-punching or coating high-temperature resistant staple fibers. The needle-punched materials primarily serve as the matrix, providing strength and initial filtration, while the coating materials, often PTFE membranes, are used for precision filtration. However, the service life of these materials continues to attract industry attention, especially in complex operating environments. After a period of use, their resistance increases significantly, and their filtration efficiency decreases significantly. To address this issue, electrostatic charging of high-temperature filter bags can improve filtration accuracy and extend their lifespan during continuous low-resistance use without increasing the bag's filtration resistance. Currently, electrostatic charging technology is most commonly used in polypropylene (PP) meltblown nonwovens for medical and sanitary applications, primarily utilizing corona and water electret charging. However, this technology is only used for some PP fibers used for ambient temperature filtration and has yet to be applied in high-temperature filtration. Summary of the Invention

[0003] In view of the problems existing in the prior art, the present invention provides a method for preparing a self-friction long-lasting electret high-temperature air filtration needle-punched composite material.

[0004] The present invention is achieved by providing a method for preparing a self-friction, long-lasting, electret, high-temperature air filtration needle-punched composite material, the method comprising:

[0005] Step 1: opening, mixing, combing and laying polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, polyimide / electret composite staple fibers, electret staple fibers and high temperature resistant hot melt staple fibers;

[0006] Step 2: After opening, mixing, combing and laying, the net is further treated by needle punching and liquid friction electret treatment;

[0007] Step three, compounding the needle-punched nonwoven material after liquid friction electret and drying temperature with a polytetrafluoroethylene microporous membrane to prepare a high-temperature resistant air filtration needle-punched filter material with a persistent electrostatic load.

[0008] Furthermore, in the step 1, the polytetrafluoroethylene / electret composite staple fiber, polyphenylene sulfide / electret composite staple fiber, polyimide / electret composite staple fiber electret staple fiber has a fineness of 1.5 to 15 denier, a length of 35 to 80 mm, an operating temperature of >200°C, a fiber strength of >4 cN / dtex, and a tensile breaking ratio of >10%.

[0009] Furthermore, in the step 1, the high temperature resistant hot-melt staple fiber is a polyamide hot-melt fiber.

[0010] Furthermore, in the step one, in the electret composite short fiber, the electret is a special electret for liquid friction electret, an organic / inorganic hybrid composite, the organic electret includes nano-scale polytetrafluoroethylene, polyperfluoroethylene propylene, ethylene-chlorotrifluoroethylene copolymer single or blend; the inorganic electret includes silicon dioxide, titanium dioxide, zinc oxide, silicon nitride, aluminum oxide, barium titanate and lead zirconate titanate single or blend; the organic / inorganic composite mass ratio is 20 / 80 to 40 / 60.

[0011] Furthermore, in the step 1, the mixed mass ratio of electret short fibers such as polytetrafluoroethylene / electret composite short fibers, polyphenylene sulfide / electret composite short fibers, and polyimide / electret composite short fibers is 60% to 90%; the mixed mass ratio of high-temperature resistant hot-melt short fibers is 10% to 40%.

[0012] Furthermore, in the step 1, polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, polyimide / electret composite staple fibers, electret staple fibers and high-temperature resistant hot-melt staple fibers are mixed by intermittent blending and dried for more than 8 hours at a temperature of 100°C before mixing and combing.

[0013] Furthermore, in the step one, during the opening and carding process of polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, and polyimide / electret composite staple fibers, the needle plate is made of nylon or acrylic polymer material, and high-frequency needling uses needles treated with an inert surface impregnated coating; the needling stroke is 10 to 30 mm, and the frequency is 600 to 1000 needles per minute.

[0014] Furthermore, in step 2, the specific process of using the acupuncture and liquid friction electret technology is as follows:

[0015] The needle-punched nonwoven material reinforced by high-frequency needle punching is further subjected to friction electret by means of liquid high-pressure jetting, and is dried after the liquid friction electret.

[0016] Furthermore, the friction liquid is ultrapure deionized water with a conductivity of less than 0.075 us / cm and a spray intensity of 20 to 40 Bar;

[0017] The drying after liquid friction electret is specifically that after liquid friction electret, the drying temperature is 100-120° C. and the moisture content after drying is less than 0.1%.

[0018] Furthermore, in the step 4, the PTFE microporous membrane has a pore size of 0.2 to 0.8 μm, a thickness of 0.5 to 1.5 mm, and an air permeability of 10 to 50 m 3 / m 2 ·min. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of a method for preparing a self-friction, long-lasting, high-temperature air filtration needle-punched composite material provided by an embodiment of the present invention.

[0020] DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] 1. Explanatory Examples In order to enable those skilled in the art to fully understand how to implement the present invention, this section provides an illustrative example that expands upon the technical solutions of the claims.

[0023] like Figure 1 As shown, the method for preparing the self-friction durable electret high-temperature air filtration needle-punched composite material provided by the embodiment of the present invention includes:

[0024] S101: opening, mixing, combing, and laying electret staple fibers such as polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, and polyimide / electret composite staple fibers and high-temperature resistant hot-melt staple fibers;

[0025] S102: After opening, mixing, combing and laying, it is further processed by needle punching and liquid friction electret technology;

[0026] S103: The needle-punched nonwoven material subjected to liquid friction electret and drying temperature is composited with a polytetrafluoroethylene microporous membrane to prepare a high-temperature resistant air filtration needle-punched filter material with a persistent electrostatic load.

[0027] In S101 provided in an embodiment of the present invention, the electret short fibers such as polytetrafluoroethylene / electret composite short fibers, polyphenylene sulfide / electret composite short fibers, polyimide / electret composite short fibers, etc. have a fineness of 1.5 to 15 deniers, a length of about 35 to 80 mm, are easy to generate static electricity by friction, have an operating temperature of >200°C, a fiber strength of >4 cN / dtex, and a tensile breaking ratio of >10%.

[0028] In S101 provided in the embodiment of the present invention, the high-temperature resistant hot-melt staple fiber is a polyamide hot-melt fiber, and its fineness is similar to that of the electret staple fiber.

[0029] In S101 provided in an embodiment of the present invention, in the electret composite short fiber, the electret is a special electret for liquid friction electret, an organic / inorganic hybrid composite, the organic electret includes a single or blend of nano-scale polytetrafluoroethylene, polyperfluoroethylene propylene, ethylene-chlorotrifluoroethylene copolymer, etc.; the inorganic electret includes a single or blend of silicon dioxide, titanium dioxide, zinc oxide, silicon nitride, aluminum oxide, barium titanate and lead zirconate titanate; the organic / inorganic composite mass ratio is about 20 / 80 to 40 / 60.

[0030] In S101 provided in an embodiment of the present invention, the mixed mass ratio of electret short fibers such as polytetrafluoroethylene / electret composite short fibers, polyphenylene sulfide / electret composite short fibers, and polyimide / electret composite short fibers is 60% to 90%; the mixed mass ratio of high-temperature resistant hot-melt short fibers is 10% to 40%.

[0031] In S101 provided in an embodiment of the present invention, electret staple fibers such as polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, and polyimide / electret composite staple fibers are mixed with high-temperature resistant hot-melt staple fibers by an intermittent blending method, and need to be dried for more than 8 hours at a temperature of 100°C before mixing and combing.

[0032] In S101 provided in the embodiments of the present invention, during the opening and carding process of staple fibers such as polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, and polyimide / electret composite staple fibers, the needle plate is made of a polymer material such as nylon or acrylic, and high-frequency needling uses needles treated with an inert impregnated coating. The needling stroke is 10 to 30 mm, and the frequency is 600 to 1000 punches / minute.

[0033] In S102 provided in the embodiment of the present invention, the specific process of the acupuncture and liquid friction electret technology is as follows:

[0034] The needle-punched nonwoven material reinforced by high-frequency needle punching is further subjected to friction electret by means of liquid high-pressure jetting, and is dried after the liquid friction electret.

[0035] The friction liquid is ultrapure deionized water with a conductivity of less than 0.075 us / cm and a spray intensity of 20 to 40 Bar.

[0036] The drying after liquid friction electret is specifically that after liquid friction electret, the drying temperature is 100-120° C. and the moisture content after drying is less than 0.1%.

[0037] In S104 provided in the embodiment of the present invention, the PTFE microporous membrane has a pore size of 0.2 to 0.8 μm, a thickness of 0.5 to 1.5 mm, and an air permeability of 10 to 50 m 3 / m 2 ·min.

[0038] 2. Application Examples: In order to demonstrate the creativity and technical value of the technical solution of the present invention, this section provides application examples of the claimed technical solution on specific products or related technologies.

[0039] Example 1 (1#)

[0040] The raw material is pure polyphenylene sulfide (PPS) short fiber. After opening, mixing, carding and laying, a single needle punching is completed to obtain non-woven material, and a blank control group is used.

[0041] Example 2 (2#)

[0042] The raw materials are pure polyphenylene sulfide (PPS) / electret short fibers. After opening, mixing, carding and laying, the nonwoven material is obtained by a single needle punching.

[0043] Example 3 (3#)

[0044] The raw material is pure polyphenylene sulfide (PPS) short fiber. After opening, mixing, carding and laying, a single needle punch is obtained to obtain a non-woven material, which is further subjected to a single friction electret of liquid and dried to obtain a non-woven material.

[0045] Example 4 (4#)

[0046] The raw materials are pure polyphenylene sulfide (PPS) / electret short fibers. After opening, mixing, combing and laying, a single needle punching is performed to obtain a nonwoven material. The nonwoven material is further subjected to a single friction electret process with liquid and dried to obtain a nonwoven material.

[0047] Example 5 (5#)

[0048] The raw material is pure polyphenylene sulfide (PPS) / electret short fiber. After opening, mixing, carding and laying, it is needle-punched 2-4 times to obtain a non-woven material. It is further electret-treated by a single friction of liquid and dried to obtain a non-woven material.

[0049] Example 6 (6#)

[0050] The raw material is pure polyphenylene sulfide (PPS) / electret short fiber. After opening, mixing, carding and laying, a single needle punch is obtained to obtain a non-woven material. It is further rubbed with liquid electret 2-4 times and dried to obtain a non-woven material.

[0051] Example 7 (7#)

[0052] The raw material is pure polyphenylene sulfide (PPS) / electret short fiber. After opening, mixing, carding and laying, it is needle-punched 2-4 times to obtain a non-woven material. It is further rubbed with liquid 2-4 times and dried to obtain a non-woven material.

[0053] Example 8 (8#)

[0054] The raw materials are pure polyphenylene sulfide (PPS) / electret short fibers and hot-adhesive, high-temperature-resistant, low-melting-point short fibers. After opening, mixing, combing, and laying, the non-woven material is needle-punched 2-4 times, further rubbed with liquid electret 2-4 times, dried, and hot-rolled to obtain the non-woven material.

[0055] Example 9 (9#)

[0056] The raw materials are pure polyphenylene sulfide (PPS) / electret short fibers and hot-adhesive, high-temperature-resistant, low-melting-point short fibers. After opening, mixing, combing, and laying, the non-woven material is needle-punched 2-4 times, further rubbed with liquid electret 2-4 times, dried, hot-rolled, and coated to obtain the non-woven material.

[0057] 3. Evidence of the effects of the embodiments: The embodiments of the present invention have achieved some positive effects during the development or use process, and indeed have great advantages over the existing technology. The following content describes them with reference to the data, charts, etc. of the experimental process.

[0058] The above examples 1# to 9# were respectively subjected to filtration performance test (0.25 μm particle size, 32 L / min flow rate), mechanical performance test, and service life test (1000 pulse spray test resistance change)

[0059] Table 4 Performance comparison of different embodiments

[0060] Sample number Filtration performance / % Filtration resistance / Pa Strong / N Service life / Pa 1# 53.2 22.1 432.4 375.5 2# 77.2 22.4 425.5 323.2 3# 82.4 23.4 456.4 313.9 4# 92.1 25.6 453.2 265.6 5# 93.4 27.2 574.3 245.2 6# 95.1 26.7 485.3 248.3 7# 97.3 32.4 592.1 221.5 8# 99.2 34.6 793.6 241.4 9# 99.99 51.4 812.2 420.5

[0061] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a self-friction long-lasting electret high-temperature air filtration needle-punched composite material, characterized in that: The method for preparing the self-friction durable electret high-temperature air filtration needle-punched composite material comprises: Step 1: opening, mixing, combing and laying polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, polyimide / electret composite staple fibers and high-temperature resistant hot-melt staple fibers; Step 2: After opening, mixing, combing and laying, the needle-punched nonwoven material is further processed by needle punching and liquid friction electret to obtain a needle-punched nonwoven material; the specific process of the needle punching and liquid friction electret technology is as follows: the needle-punched nonwoven material reinforced by high-frequency needle punching is further subjected to friction electret by friction liquid high-pressure jet, and then dried after liquid friction electret; Step 3: Compounding the needle-punched nonwoven material obtained in step 2 with a polytetrafluoroethylene microporous membrane to prepare a high-temperature resistant air filtration needle-punched filter material with a persistent electrostatic load; In the step 1, the polytetrafluoroethylene / electret composite short fibers, polyphenylene sulfide / electret composite short fibers, and polyimide / electret composite short fibers have a fineness of 1.5 to 15 deniers, a length of 35 to 80 mm, an operating temperature greater than 200° C., a fiber strength greater than 4 cN / dtex, and a tensile breaking ratio greater than 10%; In the step 1, the high temperature resistant hot-melt staple fiber is a polyamide hot-melt fiber.

2. The method for preparing the self-friction durable electret high-temperature air filtration needle-punched composite material according to claim 1, characterized in that: In the step 1, the electret is a special electret for liquid friction electret, an organic / inorganic hybrid composite, the organic electret includes nano-scale polytetrafluoroethylene, polyperfluoroethylene propylene, ethylene-chlorotrifluoroethylene copolymer, or a single or blended material; the inorganic electret includes silicon dioxide, titanium dioxide, zinc oxide, silicon nitride, aluminum oxide, barium titanate, and lead zirconate titanate, or a single or blended material; the organic / inorganic composite mass ratio is 20 / 80 to 40 / 60.

3. The method for preparing the self-friction durable electret high-temperature air filtration needle-punched composite material according to claim 1, characterized in that: In the step 1, the mixing mass ratio of polytetrafluoroethylene / electret composite short fibers, polyphenylene sulfide / electret composite short fibers, and polyimide / electret composite short fibers is 60% to 90%; the mixing mass ratio of high-temperature resistant hot-melt short fibers is 10% to 40%.

4. The method for preparing the self-friction durable electret high-temperature air filtration needle-punched composite material according to claim 1, characterized in that: In the step 1, polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, polyimide / electret composite staple fibers and high-temperature resistant hot-melt staple fibers are mixed by intermittent blending and dried for more than 8 hours at a temperature of 100° C. before mixing and combing.

5. The method for preparing the self-friction durable electret high-temperature air filtration needle-punched composite material according to claim 1, characterized in that: In the step 1, during the opening and carding process of polytetrafluoroethylene / electret composite staple fibers, polyphenylene sulfide / electret composite staple fibers, and polyimide / electret composite staple fibers, the needle plate is made of nylon or acrylic polymer materials, and high-frequency needling uses needles treated with an inert impregnated coating on the surface; the needling stroke is 10 to 30 mm, and the frequency is 600 to 1000 needles per minute.

6. The method for preparing the self-friction durable electret high-temperature air filtration needle-punched composite material according to claim 1, characterized in that: The friction liquid is ultrapure deionized water with a conductivity of less than 0.075 us / cm and a spray intensity of 20 to 40 bar; The drying after liquid friction electret is specifically that after liquid friction electret, the drying temperature is 100-120° C. and the moisture content after drying is less than 0.1%.

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