High-temperature-resistant glass fiber air filter paper and preparation method thereof

Abstract

The invention provides high-temperature-resistant glass fiber air filter paper and a preparation method thereof.The preparation method comprises the following steps that modified organic fibers, chopped glass fibers and glass fiber cotton are sequentially added into water to be mixed, and mixed slurry is obtained; the mixed pulp is subjected to slushing and netting, composite fiber filter paper is obtained after wet-process papermaking, the surface of the composite fiber filter paper is sized with the modified composite sizing liquid, and the high-temperature-resistant glass fiber air filter paper is obtained after curing. Wherein the modified composite sizing liquid comprises a modified acrylic emulsion and a fluorine-series waterproof agent. The prepared high-temperature-resistant glass fiber air filter paper can tolerate the working condition temperature of 200-300 DEG C, the transverse strength loss of a filter made of the high-temperature-resistant glass fiber air filter paper is lower than 30% under the condition of continuous blowing of 250 DEG C hot air, meanwhile, the filter paper has excellent waterproof performance, the waterproof performance of the filter paper can reach 800 mmH2O or above, and the strength loss of the filter is not higher than 20% in a 70-80% high-humidity environment.

Description

Technical Field

[0001] This invention relates to the field of air filtration materials technology, and in particular to a high-temperature resistant glass fiber air filter paper and its preparation method. Background Technology

[0002] Fiberglass air filter paper (hereinafter referred to as "fiberglass air filter paper") is a key component of air filters, and its performance determines the filtration effect of the air filter. The painting workshop is a professional painting workshop, and the normal temperature area and high temperature area have different process requirements for filter paper. Especially on the high temperature baking production line, the air supplied needs to be preheated to between 200 and 300 degrees Celsius. Since the heating device will generate dust, the air filter must be placed at the hot air end. This requires that the fiberglass air filter paper used can withstand the high temperature of 200 to 300 degrees Celsius for a long time.

[0003] However, existing air filters used in high-temperature environments generally use pure glass fiber air filter paper with metal separators such as aluminum foil. This type of air filter paper has insufficient high-temperature resistance, low strength, is not conducive to mechanized production, and is prone to leakage problems during long-term high-temperature use, affecting the reliability and efficiency of filtration.

[0004] Therefore, there is an urgent need to provide a high-temperature resistant glass fiber air filter paper and its preparation method. Summary of the Invention

[0005] This invention provides a high-temperature resistant glass fiber air filter paper and its preparation method, which can solve the problems of existing air filter materials having low strength, insufficient high-temperature resistance, and decreased filtration performance under long-term high-temperature environments.

[0006] In a first aspect, the present invention provides a high-temperature resistant glass fiber air filter paper, the preparation method of which includes the following steps: (1) The modified organic fiber is added to water in sequence with chopped glass fiber and glass fiber cotton and mixed evenly to obtain a mixed slurry; wherein the modified organic fiber is modified polyethylene terephthalate fiber. (2) The mixed slurry is slurried and fed onto the web, and after wet papermaking, composite fiber filter paper is obtained. A modified composite sizing liquid is used to apply sizing to the surface of the composite fiber filter paper, and after curing, the high temperature resistant glass fiber air filter paper is obtained; wherein, the modified composite sizing liquid includes modified acrylic emulsion and fluorine waterproofing agent.

[0007] Preferably, in step (1), the modified organic fiber is prepared by the following method: (11) Polyethylene terephthalate fiber and nano-silica were melt-mixed using a twin-screw extruder, and then extruded and granulated to obtain a mixed masterbatch; (12) The mixed masterbatch is mixed with polyethylene terephthalate fiber and then melt-spun to obtain the modified organic fiber.

[0008] Preferably, in step (11), the nano-silica is 1-10% by mass percentage and the polyethylene terephthalate fiber is 90-99%.

[0009] Preferably, in step (12), the mixed masterbatch is 5-20% by mass percentage and the polyethylene terephthalate fiber is 80-95%.

[0010] Preferably, in step (1), the modified organic fiber has a diameter of 4.5~45μm, a fineness of 0.2~2.0D, a softening point of 130~150℃, and a high-temperature melting point of 250~280℃.

[0011] Preferably, in step (1), the chopped glass fiber has a diameter of 5~10μm and a length of 7~15mm.

[0012] Preferably, in step (1), the modified organic fiber is 1-15% by mass percentage, the chopped glass fiber is 5-29% by mass percentage, and the glass fiber cotton is 70-80%.

[0013] Preferably, in step (1), the slurry concentration is 0.05~0.25%.

[0014] Preferably, in step (1), the pulp concentration after mixing the modified organic fiber and chopped glass fiber is 5-10%, and the dissolution time is 30-100s; the pulp concentration after adding glass fiber cotton is 1-4%, and the dissolution time is 50-600s.

[0015] Preferably, in step (2), the modified acrylic emulsion is composed of modified RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion.

[0016] More preferably, the mass ratio of modified RESIN HF-05A acrylic emulsion to PRIMAL E-32NP acrylic emulsion is (1~10):1.

[0017] Preferably, by mass percentage, the modified composite sizing agent comprises 80-90% modified acrylic emulsion and 10-20% fluorinated waterproofing agent.

[0018] Preferably, in step (2), the modified RESIN HF-05A acrylic emulsion is obtained by organosilicon modification.

[0019] More preferably, the organosilicon is vinyltriethoxysilane or octamethylcyclotetrasiloxane.

[0020] More preferably, the modified RESIN HF-05A acrylic emulsion contains 20-25% organosilicon.

[0021] Preferably, in step (2), the curing is a three-stage gradient cooling curing; wherein, the temperature of the first stage is 200~230℃ and the time is 60~80s; the temperature of the second stage is 140~180℃ and the time is 60~80s; and the temperature of the third stage is 80~110℃ and the time is 150~200s.

[0022] Secondly, embodiments of the present invention also provide a high-temperature resistant glass fiber air filter paper, which is prepared by any of the preparation methods described in the first aspect above.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects: (1) In this invention, modified polyethylene terephthalate fibers are mixed and dissolved with chopped glass fibers and glass fiber cotton in water to form a mixed slurry. The mixed slurry is then wet-processed to form a composite fiber filter paper. The modified polyethylene terephthalate fibers have significantly improved heat resistance, enabling the filter paper to maintain structural stability at high temperatures. Furthermore, they can interweave with rigid chopped glass fibers and fluffy glass fiber cotton to form a three-dimensional network structure that combines rigidity and flexibility, thereby forming a composite fiber filter paper substrate with high strength, good flexibility, and excellent temperature resistance. Subsequently, a modified acrylic emulsion and fluorine-based protective film are used to form the composite fiber filter paper substrate. A modified composite sizing solution prepared with water is used to sizing the surface of fiber filter paper. The modified acrylic emulsion has excellent heat resistance and weather resistance. Under high temperature conditions, it can undergo a cross-linking reaction to form a network structure, thereby further enhancing the high temperature resistance of the filter paper. At the same time, when used in combination with fluorinated waterproofing agents, it can play a dual synergistic role. On the one hand, the high bond energy FF bonds in the fluorinated waterproofing agent molecules can further consolidate the thermal stability of the filter paper. On the other hand, its extremely low surface tension perfluoroalkyl chains can endow the filter paper with excellent hydrophobic and moisture-resistant properties. The synergy between the two ensures the excellent performance of the filter paper in continuous high temperature and high humidity environments. (2) The high-temperature resistant glass fiber air filter paper prepared in this invention can withstand working temperatures of 200~300℃, and under continuous hot air blowing conditions at 250℃, the transverse strength loss of the filter is less than 30%. At the same time, the filter paper has excellent waterproof performance, with a waterproof rating of more than 800mmH2O. In a high humidity environment of 70-80%, the strength loss of the filter is no more than 20%. Thus, under the premise of ensuring filtration accuracy, the filter as a whole exhibits good structural integrity, with no leakage and no lint, thereby significantly extending its service life. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but 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.

[0025] This invention provides a high-temperature resistant glass fiber air filter paper, the preparation method of which includes the following steps: (1) The modified organic fiber is added to water in sequence with chopped glass fiber and glass fiber cotton and mixed evenly to obtain a mixed slurry; wherein the modified organic fiber is modified polyethylene terephthalate fiber. (2) The mixed slurry is slurried and fed onto the web, and after wet papermaking, composite fiber filter paper is obtained. A modified composite sizing liquid is used to apply sizing to the surface of the composite fiber filter paper, and after curing, the high temperature resistant glass fiber air filter paper is obtained; wherein, the modified composite sizing liquid includes modified acrylic emulsion and fluorine waterproofing agent.

[0026] In this embodiment of the invention, modified polyethylene terephthalate (PET) fibers are mixed with chopped glass fibers and glass fiber cotton in water to form a mixed slurry. This slurry is then processed using a wet papermaking process to form composite fiber filter paper. The modified PET fibers exhibit significantly improved heat resistance, enabling the filter paper to maintain structural stability at high temperatures. Furthermore, they can interweave with rigid chopped glass fibers and fluffy glass fiber cotton to form a three-dimensional network structure that combines rigidity and flexibility, resulting in a composite fiber filter paper substrate with high strength, good flexibility, and excellent temperature resistance. Subsequently, a modified acrylic emulsion and fluorine-based protective film are used... A modified composite sizing solution prepared with water is used to sizing the surface of fiber filter paper. The modified acrylic emulsion has excellent heat resistance and weather resistance. Under high temperature conditions, it can undergo a cross-linking reaction to form a network structure, thereby further enhancing the high temperature resistance of the filter paper. At the same time, when used in combination with a fluorinated waterproofing agent, it can play a dual synergistic role. On the one hand, the high bond energy FF bonds in the fluorinated waterproofing agent molecule can further consolidate the thermal stability of the material. On the other hand, its extremely low surface tension perfluoroalkyl chain can endow the filter paper with excellent hydrophobic and moisture-resistant properties. The synergy between the two ensures the excellent performance of the filter paper in continuous high temperature and high humidity environments.

[0027] According to some preferred embodiments, in step (1), the modified organic fiber is prepared by the following method: (11) Polyethylene terephthalate fiber and nano-silica were melt-mixed using a twin-screw extruder, and then extruded and granulated to obtain a mixed masterbatch; (12) The mixed masterbatch is mixed with polyethylene terephthalate fiber and then melt-spun to obtain the modified organic fiber.

[0028] According to some preferred embodiments, in step (11), by mass percentage, nano-silica is 1-10% (e.g., it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%), and polyethylene terephthalate fiber is 90-99% (e.g., it can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99%); in step (12), by mass percentage, mixed masterbatch is 5-20% (e.g., it can be 5%, 10%, 15% or 20%), and polyethylene terephthalate fiber is 80-95% (e.g., it can be 80%, 82%, 85%, 88%, 90% or 95%).

[0029] In this embodiment of the invention, nano-silica and polyethylene terephthalate (PET) are first mixed in a certain proportion and then melt-granulated to form a uniformly dispersed mixed masterbatch. Then, it is melt-spun again with pure PET in a set proportion. This ensures that the nano-silica is uniformly dispersed at the nanoscale in the fiber. At the same time, by reasonably controlling the proportion of nano-silica introduced, the heat resistance and mechanical strength of the organic fiber can be significantly improved, while basically maintaining the original processability and surface characteristics of the fiber. This results in a modified organic fiber that not only maintains its structural integrity at high temperatures of 200-300°C, but also synergistically enhances the overall performance of the filter paper when combined with glass fiber.

[0030] According to some preferred embodiments, in step (1), the modified organic fiber has a diameter of 4.5~45μm (e.g., it can be 4.5μm, 5μm, 10μm, 20μm, 30μm, 40μm or 45μm), a fineness of 0.2~2.0D (e.g., it can be 0.2D, 0.5D, 1.0D, 1.5D or 2.0D), a softening point of 130~150℃ (e.g., it can be 130℃, 140℃ or 150℃), and a high-temperature melting point of 250~280℃ (e.g., it can be 250℃, 260℃, 270℃ or 280℃); the chopped glass fiber has a diameter of 5~10μm (e.g., it can be 5μm, 6μm, 8μm or 10μm) and a length of 7~15mm (e.g., it can be 7mm, 8mm, 10mm, 12mm or 15mm).

[0031] According to some preferred embodiments, in step (1), the modified organic fiber is 1-15% by mass percentage (e.g., 1%, 3%, 5%, 7%, 8%, 10%, 12% or 15%), the chopped glass fiber is 5-29% (e.g., 5%, 8%, 10%, 12%, 15%, 18%, 20%, 25% or 29%), and the glass fiber cotton is 70-80% (e.g., 70%, 72%, 75%, 78% or 80%); the sizing concentration of the mixed slurry is 0.05-0.25% (e.g., 0.05%, 0.1%, 0.15%, 0.20% or 0.25%).

[0032] In this embodiment of the invention, by mixing the modified organic fibers with chopped glass fibers and glass fiber cotton in a certain proportion for wet papermaking, the heat resistance of the modified polyethylene terephthalate fibers is significantly improved, enabling the filter paper to maintain structural stability at high temperatures. It can interweave with rigid chopped glass fibers and fluffy glass fiber cotton to form a three-dimensional network structure that combines rigidity and flexibility. This is beneficial for producing composite fiber filter paper with high strength, high temperature resistance and good flexibility. Furthermore, this multi-component composite fiber filter paper structure fundamentally reduces the risk of leakage caused by fiber breakage or interface separation, and improves the long-term filtration reliability of the filter paper under harsh conditions such as high temperature and vibration.

[0033] According to some preferred embodiments, in step (1), the pulp concentration after mixing the modified organic fiber and chopped glass fiber is 5-10% (e.g., 5%, 6%, 7%, 8%, 9% or 10%), and the disintegration time is 30-100s (e.g., 30s, 50s, 80s or 100s); the pulp concentration after adding glass fiber cotton is 1-4% (e.g., 1%, 2%, 3% or 4%), and the disintegration time is 50-600s (e.g., 50s, 100s, 150s, 200s, 300s, 400s, 500s or 600s).

[0034] To ensure a uniform and stable three-dimensional network structure of modified organic fibers, chopped glass fibers, and glass fiber cotton in subsequent papermaking, in this embodiment of the invention, the modified organic fibers and chopped glass fibers are first dispersed for a period of time under the action of a hydraulic pulper at a certain pulping concentration, so that the modified organic fibers and chopped glass fibers are fully dispersed and intertwined. Then, glass fiber cotton is added to adjust the pulping concentration and dispersed again under the action of a hydraulic pulper, so that the glass fiber cotton fills the structure formed by the above mixed pulp, thereby effectively avoiding uneven dispersion or agglomeration caused by differences in fiber characteristics, so that the three fibers are uniformly interwoven and tightly combined, which is conducive to the preparation of composite fiber filter paper with uniform structure and stable performance through subsequent wet forming.

[0035] According to some preferred embodiments, in step (2), the modified acrylic emulsion is composed of modified RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion; the mass ratio of modified RESIN HF-05A acrylic emulsion to PRIMAL E-32NP acrylic emulsion is (1~10):1 (for example, it can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1); the modified RESIN HF-05A acrylic emulsion is obtained by organosilicon modification; preferably, the organosilicon is vinyltriethoxysilane or octamethylcyclotetrasiloxane; in the modified RESIN HF-05A acrylic emulsion, the amount of organosilicon added is 20~25% (for example, it can be 20%, 21%, 22%, 23%, 24% or 25%), and the amount of RESIN HF-05A acrylic emulsion added is 75~80%.

[0036] In this embodiment of the invention, after extensive experimental screening, a composite propylene emulsion system was formed by compounding RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion, both exhibiting excellent temperature resistance. RESIN HF-05A acrylic emulsion is a thermosetting, self-crosslinking acrylic resin that can undergo a crosslinking reaction at high temperatures to form a network structure, thereby significantly improving its high-temperature resistance. PRIMAL E-32NP acrylic emulsion is a self-crosslinking polymer, which is beneficial for further enhancing the strength and toughness of the glass fiber air filter paper. Simultaneously, this embodiment of the invention uses organosilicon to modify RESIN HF-05A acrylic emulsion. The bond energy of the Si-O-Si bonds in the main chain of the organosilicon polymer is much higher than that of the C-C bonds in conventional organic polymers. After organosilicon modification, the heat resistance and weather resistance of the acrylic emulsion can be further improved. In practical applications, the introduced siloxane groups can undergo hydrolysis and condensation under high temperature and ambient humidity, forming a strong Si-O-Si three-dimensional crosslinked network, thereby significantly increasing the heat resistance temperature of the material to 250℃ or even higher. Meanwhile, the unmodified PRIMAL E-32NP, as a self-crosslinking polymer, provides the filter paper with the necessary strength and toughness. When the modified RESIN HF-05A acrylic emulsion is compounded with the PRIMAL E-32NP acrylic emulsion, the resulting composite emulsion system, after curing into a film at 180-230°C, further promotes the tight interweaving of fibers in the filter paper. This results in a longitudinal and transverse strength loss of less than 30% when the filter paper is blown by hot air at 200-300°C. Filters made using this system are less prone to cracking and pilling under high-temperature conditions. Furthermore, the composite emulsion system, when used synergistically with fluorinated waterproofing agents, exhibits a synergistic effect. On one hand, the high-bond-energy FF bonds in the fluorinated waterproofing agent molecules further enhance the thermal stability of the filter paper. On the other hand, the extremely low surface tension perfluoroalkyl chains impart excellent hydrophobic and moisture-resistant properties to the filter paper. This synergy ensures the long-term stable use of the filter paper under continuous high-temperature and high-humidity environments.

[0037] According to some preferred embodiments, the modified composite sizing agent contains 80-90% modified acrylic emulsion (e.g., 80%, 82%, 85%, 88% or 90%) and 10-20% fluorinated waterproofing agent (e.g., 10%, 12%, 15%, 18% or 20%) by weight percentage.

[0038] Experiments conducted according to this invention have confirmed that optimizing the process ratio of modified RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion facilitates synergistic and complementary performance between the two, thereby optimizing the overall physicochemical properties of the glass fiber air filter paper (especially its long-term high-temperature resistance). If the content of modified RESIN HF-05A acrylic emulsion is too low, the three-dimensional network structure formed by cross-linking and curing of the filter paper under high-temperature conditions will be unable to provide stable mechanical properties, and the temperature resistance will decrease. Conversely, if the content of PRIMAL E-32NP acrylic emulsion is too low, the flexibility and toughness of the filter paper will decrease after cross-linking and curing under high-temperature conditions, and the strength loss will exceed 30% under 250°C hot air purging, making it prone to deformation or even breakage, thus affecting the filtration performance.

[0039] Meanwhile, the composite acrylic emulsion system formed above is mixed with a fluorinated waterproofing agent in a certain proportion. The two work synergistically to ensure that the glass fiber air filter paper can maintain its structural integrity and stable performance under high temperature and high humidity conditions, meeting the requirements for long-term use in harsh environments. Experiments of this invention have confirmed that if the content of the fluorinated waterproofing agent is too low, the number of perfluoroalkyl chains will decrease, the surface tension of the filter paper will not meet the waterproofing requirements, and the filter paper will be wetted in high humidity environments, resulting in a decrease in strength, deformation, or even breakage. On the other hand, if the content of the fluorinated waterproofing agent is too high, on the one hand, the number of FF bonds will increase, the energy required for cross-linking and curing will increase, resulting in an increase in the heat required for drying, and there is a risk of insufficient curing, which will not achieve the purpose of improving waterproof performance. On the other hand, the increased amount of fluorinated waterproofing agent will also increase the production cost.

[0040] According to some preferred embodiments, in step (2), the curing is a three-stage gradient cooling curing; wherein, the temperature of the first stage is 200~230℃ (for example, it can be 200℃, 210℃, 220℃ or 230℃), and the time is 60~80s (for example, it can be 60s, 70s or 80s); the temperature of the second stage is 140~180℃ (for example, it can be 140℃, 150℃, 160℃, 170℃ or 180℃), and the time is 60~80s (for example, it can be 60s, 70s or 80s); the temperature of the third stage is 80~110℃ (for example, it can be 80℃, 90℃, 100℃ or 110℃), and the time is 150~180s (for example, it can be 150s, 160s, 170s or 180s).

[0041] In this embodiment of the invention, after the sizing is applied to both sides of the fiber filter paper, it is cured by gradient cooling, which allows the modified acrylic emulsion to fully undergo cross-linking reaction, promotes the formation of Si-O-Si high-temperature resistant network structure, and enables the sizing layer to shrink uniformly during the curing process, which is beneficial to forming a dense, continuous and strongly adhesive functional sizing coating on the surface of the composite fiber filter paper.

[0042] This invention also provides a high-temperature resistant glass fiber air filter paper, which is prepared using any of the preparation methods described above.

[0043] The high-temperature resistant glass fiber air filter paper prepared as described above can withstand operating temperatures of 200~300℃. Under continuous hot air purging at 250℃, the transverse strength loss of the filter made from it is less than 30%. At the same time, the filter paper has excellent waterproof performance, with a waterproof rating of over 800mmH2O. In a high humidity environment of 70-80%, the strength loss of the filter is no more than 20%. Thus, while ensuring filtration accuracy, the filter as a whole exhibits good structural integrity, with no leakage and no linting, thereby significantly extending its service life.

[0044] Meanwhile, the high-temperature resistant glass fiber air filter paper of the present invention can be widely used in clean working environments with high requirements for terminal temperature in automobile painting workshops, hospital operating rooms, biopharmaceuticals, microelectronics, food processing or purification equipment, ultra-clean ovens and other equipment and systems that require high-temperature air purification.

[0045] To more clearly illustrate the technical solution and advantages of the present invention, the following describes in detail, through several embodiments, a high-temperature resistant glass fiber air filter paper and its preparation method. Example 1:

[0046] (1) Preparation of modified organic fibers: 95 wt% polyethylene terephthalate and 5 wt% nano silica were initially mixed in a high-speed mixer, and then the mixture was melt-mixed at 268°C using a twin-screw extruder. After extrusion, cooling and granulation, the mixed masterbatch was obtained. 10 wt% of mixed masterbatch was mixed with 90 wt% of polyethylene terephthalate chips, and after melt spinning at 275℃, modified organic fibers with a diameter of 45 μm and a fineness of 2D were obtained. 10 wt% of modified organic fiber and 5 wt% of chopped glass fiber were mixed and compounded, and then slurried for 100 s under the action of a hydraulic pulper to obtain a pulp concentration of 10%. Then 85 wt% of glass fiber wool was added, and the pulp concentration was controlled at 4%. The mixture was slurried for another 300 s under the action of a hydraulic pulper to obtain a mixed pulp. (2) Then, after the pulp is slurryed and the pulp concentration is adjusted to 0.2%, the dewatering vacuum pressure is adjusted to 50 kPa, and the composite fiber filter paper is obtained after wet papermaking; 25% organosilicon (vinyltriethoxysilane) and 75% RESIN HF-05A acrylic emulsion were mixed in a certain proportion to obtain modified RESIN HF-05A acrylic emulsion; then, the modified RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion were mixed at a mass ratio of 9:1 to obtain modified acrylic emulsion; then, 80wt% of the modified acrylic emulsion and 20wt% of fluorine-based waterproofing agent (F10 fluorine-based waterproofing agent) were stirred and mixed evenly to obtain modified composite sizing agent; A modified composite sizing solution was applied to the upper and lower surfaces of the composite fiber filter paper, and then dried and cured at 220℃, 160℃ and 100℃ for 280s in sequence to obtain high-temperature resistant glass fiber air filter paper. Example 2:

[0047] (1) Preparation of modified organic fibers: 95 wt% polyethylene terephthalate and 5 wt% nano silica were initially mixed in a high-speed mixer, and then the mixture was melt-mixed at 270°C using a twin-screw extruder. After extrusion, cooling and granulation, the mixed masterbatch was obtained. 10 wt% of mixed masterbatch was mixed with 90 wt% of polyethylene terephthalate chips, and after melt spinning at 275℃, modified organic fibers with a diameter of 45 μm and a fineness of 2D were obtained. 2 wt% of modified organic fiber and 22 wt% of chopped glass fiber were mixed and compounded, and then slurried for 100 s under the action of a hydraulic pulper to obtain a pulp concentration of 10%. Then 76 wt% of glass fiber wool was added, and the pulp concentration was controlled at 4%. The mixture was slurried for another 300 s under the action of a hydraulic pulper to obtain a mixed pulp. (2) Then, after the pulp is slurry is slurry slurry concentration is adjusted to 0.08% and the dewatering vacuum pressure is adjusted to 80 kPa. After wet papermaking, composite fiber filter paper is obtained. 20% organosilicon (vinyltriethoxysilane) and 80% RESIN HF-05A acrylic emulsion were mixed in a certain proportion to obtain modified RESIN HF-05A acrylic emulsion; then, the modified RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion were mixed at a mass ratio of 6:1 to obtain modified acrylic emulsion; then, 88wt% of the modified acrylic emulsion and 12wt% of fluorine-based waterproofing agent (F10 fluorine-based waterproofing agent) were stirred and mixed evenly to obtain modified composite sizing agent; A modified composite sizing solution was applied to the upper and lower surfaces of the composite fiber filter paper, and then dried and cured at 230℃, 140℃ and 80℃ for 350s in sequence to obtain high-temperature resistant glass fiber air filter paper. Example 3:

[0048] Example 3 is basically the same as Example 1, except that in step (1), 20wt% of modified organic fiber and 22wt% of chopped glass fiber are mixed and compounded, and the mixture is decomposed for 100s under the action of a hydraulic pulper, with a pulp concentration of 10%. Then, 58wt% of glass fiber cotton is added, and the pulp concentration is controlled to be 4%. The mixture is decomposed for another 300s under the action of a hydraulic pulper to obtain a mixed pulp. Example 4:

[0049] Example 4 is basically the same as Example 1, except that in step (2), the modified RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion are mixed at a mass ratio of 15:1 to obtain the modified acrylic emulsion. Example 5:

[0050] Example 5 is basically the same as Example 1, except that 95wt% of modified acrylic emulsion and 5wt% of fluorine-based waterproofing agent (F10 fluorine-based waterproofing agent) are stirred and mixed to obtain modified composite sizing agent. Comparative Example 1

[0051] Comparative Example 1 is basically the same as Example 1, except that in step (2), acrylic emulsion E0503 and acrylic emulsion IRW-E007 are mixed at a mass ratio of 9:1 to obtain acrylic composite emulsion; then 80wt% of acrylic composite emulsion and 20wt% of fluorine waterproofing agent (F10 fluorine waterproofing agent) are stirred and mixed to obtain modified composite sizing agent. Comparative Example 2

[0052] Comparative Example 2 is basically the same as Example 2, except that in step (2), acrylic emulsion E0503 and acrylic emulsion IRW-E007 are mixed at a mass ratio of 6:1 to obtain acrylic composite emulsion; then 88wt% of acrylic composite emulsion and 12wt% of fluorine waterproofing agent (F10 fluorine waterproofing agent) are stirred and mixed to obtain modified composite sizing agent. Comparative Example 3

[0053] Comparative Example 3 is basically the same as Example 1, except that in step (1), nano-silica is not used to modify polyethylene terephthalate. Instead, 2 wt% of polyethylene terephthalate organic fiber and 22 wt% of chopped glass fiber are directly mixed and compounded. The mixture is then decomposed for 100 s under the action of a hydraulic pulper, resulting in a pulp concentration of 10%. Then, 76 wt% of glass fiber cotton is added, and the pulp concentration is controlled to be 4%. The mixture is then decomposed for another 300 s under the action of a hydraulic pulper to obtain a mixed pulp. Comparative Example 4

[0054] Comparative Example 4 is basically the same as Example 1, except that in step (1), no organic fiber is added. Instead, 22wt% of chopped glass fiber and 88wt% of glass fiber cotton are directly mixed and pulped at a concentration of 4% for 600s under the action of a hydraulic pulper to obtain a mixed pulp. Comparative Example 5

[0055] Comparative Example 5 is basically the same as Example 1, except that in step (2), silicone is not used to modify RESINHF-05A acrylic emulsion. Instead, RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion are directly mixed at a mass ratio of 9:1 to obtain modified acrylic emulsion. Then, 80wt% of the modified acrylic emulsion is stirred and mixed with 20wt% of fluorine waterproofing agent (F10 fluorine waterproofing agent) to obtain modified composite sizing agent. Comparative Example 6

[0056] Comparative Example 6 is basically the same as Example 1, except that in step (2), no fluorine waterproofing agent is added, that is, 25% organosilicon (vinyltriethoxysilane) and 75% RESIN HF-05A acrylic emulsion are directly mixed in proportion to obtain modified RESIN HF-05A acrylic emulsion; then the modified RESIN HF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion are mixed in a mass ratio of 9:1 to obtain modified composite sizing agent.

[0057] The performance of the high-temperature resistant glass fiber air filter paper samples provided in the examples and comparative examples was tested, and the test results are shown in Table 1 below: The transverse strength test was conducted in accordance with GB / T 12914; the waterproof test was conducted in accordance with CRAA433, with a water pressure rise rate of 6.0 kPa / min ± 0.15 kPa / min; and the filter leak test was conducted in accordance with GB / T 13554-2020.

[0058] Table 1 As shown in Table 1, the high-temperature resistant glass fiber air filter paper prepared by this invention has excellent temperature resistance. Under continuous hot air purging at 250℃, the transverse strength loss of the filter made from it is less than 30%. At the same time, the filter paper has excellent waterproof performance, with a waterproof rating of over 800 mmH2O. In a high humidity environment of 70-80%, the strength loss of the filter is no more than 20%. While ensuring filtration accuracy, the filter as a whole exhibits good structural integrity, with no leakage and no linting, thus significantly extending its service life.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-temperature resistant glass fiber air filter paper, characterized in that, The preparation method includes the following steps: (1) The modified organic fiber is added to water in sequence with chopped glass fiber and glass fiber cotton to obtain a mixed slurry; wherein the modified organic fiber is modified polyethylene terephthalate fiber; (2) The mixed slurry is slurried and fed onto the web, and after wet papermaking, composite fiber filter paper is obtained. A modified composite sizing liquid is used to apply sizing to the surface of the composite fiber filter paper, and after curing, the high temperature resistant glass fiber air filter paper is obtained; wherein, the modified composite sizing liquid includes modified acrylic emulsion and fluorine waterproofing agent.

2. The preparation method according to claim 1, characterized in that, In step (1), the modified organic fiber is prepared by the following method: (11) Polyethylene terephthalate and nano-silica were melt-mixed using a twin-screw extruder, and then extruded and granulated to obtain a mixed masterbatch; (12) The mixed masterbatch is mixed with polyethylene terephthalate and then melt-spun to obtain the modified organic fiber.

3. The preparation method according to claim 2, characterized in that, In step (11), by mass percentage, nano-silica comprises 1-10%, and polyethylene terephthalate fiber comprises 90-99%; and / or In step (12), the mixed masterbatch is 5-20% by mass percentage and the polyethylene terephthalate fiber is 80-95%.

4. The preparation method according to claim 1, characterized in that, In step (1), the modified organic fiber has a diameter of 4.5~45μm, a fineness of 0.2~2.0D, a softening point of 130~150℃, and a high-temperature melting point of 250~280℃; The chopped glass fibers have a diameter of 5~10μm and a length of 7~15mm.

5. The preparation method according to claim 1, characterized in that, In step (1), by mass percentage, the modified organic fiber is 1-15%, the chopped glass fiber is 5-29%, and the glass fiber wool is 70-80%; and / or The slurry concentration is 0.05~0.25%.

6. The preparation method according to claim 1, characterized in that, In step (1), the pulp concentration after mixing modified organic fiber and chopped glass fiber is 5-10%, and the dissolution time is 30-100s; the pulp concentration after adding glass fiber cotton is 1-4%, and the dissolution time is 50-600s.

7. The preparation method according to claim 1, characterized in that, In step (2), the modified acrylic emulsion is composed of modified RESINHF-05A acrylic emulsion and PRIMAL E-32NP acrylic emulsion; Preferably, the mass ratio of modified RESIN HF-05A acrylic emulsion to PRIMALE-32NP acrylic emulsion is (1~10):1; and / or By mass percentage, the modified composite sizing agent comprises 80-90% modified acrylic emulsion and 10-20% fluorinated waterproofing agent.

8. The preparation method according to claim 7, characterized in that, In step (2), the modified RESINHF-05A acrylic emulsion is obtained by organosilicon modification; Preferably, the organosilicon is vinyltriethoxysilane or octamethylcyclotetrasiloxane; More preferably, the modified RESINHF-05A acrylic emulsion contains 20-25% organosilicon.

9. The preparation method according to claim 1, characterized in that, In step (2), the curing is a three-stage gradient cooling curing; wherein, the temperature of the first stage is 200~230℃ and the time is 60~80s; the temperature of the second stage is 140~180℃ and the time is 60~80s; and the temperature of the third stage is 80~110℃ and the time is 150~200s.

10. A high-temperature resistant glass fiber air filter paper, characterized in that, It is prepared by any one of the preparation methods according to claims 1 to 9.

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