Charged nonwoven fabric filter medium and air filter unit having same

Abstract

The present invention improves low air purifying effects when installed in a household room air conditioner, which is a problem with a conventional charged nonwoven fabric filter medium.　The conventional problem is solved by a charged nonwoven fabric filter medium having a QF value of 0.10 Pa-1 or more at a wind speed of 6.5 m / min and a QF value / filter medium thickness of 0.18 Pa-1 / mm or more.

Description

Charged nonwoven fabric filter material and air filter unit having same

[0001] The present invention relates to an electrically charged nonwoven fabric filtering material and an air filter unit for use in a home room air conditioner.

[0002] Air conditioners used for indoor heating, cooling, and dehumidification are equipped with mesh filters that capture dust. These filters have poor performance in capturing fine particles such as PM2.5 and airborne viruses, and in purifying the air they inhale. Therefore, when used in a sealed room, the repeated intake and exhaust of air by the air conditioner spreads airborne viruses, bacteria, dust, and other particles throughout the room, which is unhygienic. Furthermore, bacteria that adhere to the air conditioner itself can multiply, causing odors and stains.

[0003] To solve these problems, the installation of air purification filters in air conditioners has been considered. Patent Document 1 describes a method of purifying air by attaching a pleated air purification filter inserted into a resin case to the front side of the air conditioner's intake grille. Patent Document 2 describes an air conditioner intake air purification system in which an external unit equipped with a high-performance filter and a suction motor is attached to the air conditioner main body, and the air is purified by drawing in purified air into the air conditioner.

[0004] Japanese Utility Model Registration No. 3054570 Japanese Patent Application Laid-Open No. 2022-110965

[0005] However, in the technology described in Patent Document 1, the air purification filter is attached with an area that is considerably smaller than the area of ​​the intake grille, so most of the air drawn into the air conditioner cannot pass through the air purification filter, resulting in a problem of low air purification effect.

[0006] Furthermore, the technology described in Patent Document 2 requires the installation of an external air purifier unit, which is costly. Furthermore, if a filter is directly mounted on the intake grill of the air conditioner body, the intake air volume decreases, which causes a problem of reducing the air conditioner's inherent heating and cooling capacity.

[0007] The present invention relates to an electrically charged nonwoven fabric filter material and an air filter unit to be installed in a domestic room air conditioner, which solves the problems described above; because the filter material and air filter unit exhibit excellent QF values, even when installed in the air conditioner intake port, there is only a small reduction in intake air volume and they demonstrate high air purification capabilities.

[0008] In order to solve the above problems, the electrically charged nonwoven fabric filter material of the present invention and the air filter unit having the same have the following characteristics: (1) A QF value of 0.10 Pa at a wind speed of 6.5 m / min. －１ or more, and the QF value / filter material thickness is 0.18 Pa －１ (2) The charged nonwoven fabric filter material according to (1), characterized in that it has at least a charged nonwoven fabric layer and a support layer. (3) The charged nonwoven fabric filter material according to (2), characterized in that the support layer has a bending resistance of 1300 μN or more. (4) An air filter unit comprising a pleated filter material in which the charged nonwoven fabric filter material according to any one of (1) to (3) is pleated, and a frame, wherein the thickness of the air filter unit is 20 mm or less, the fold height / pleat spacing of the pleated filter material is 3.0 to 10.0, and the QF value when the air velocity at the filter opening is 1.1 m / s is 0.10 Pa or less. －１ (5) The air filter unit according to (4), which is for installation in a residential room air conditioner. (6) The air filter unit according to (5), which is for installation in an air conditioner intake port of the residential room air conditioner.

[0009] The charged nonwoven fabric filter material and air filter unit of the present invention exhibit excellent QF values, and therefore even when mounted on the intake port of a domestic room air conditioner, there is only a small decrease in intake air volume (pressure loss), and high air purification capacity can be demonstrated.

[0010] Fig. 4 is a perspective view of an air conditioner used in an embodiment of the present invention. Fig. 5 is a perspective view of an example in which an air filter unit is installed in an air conditioner used in an embodiment of the present invention. Fig. 6 is a schematic perspective view of an air filter unit in which a frame body is arranged around a filter formed by fixing a separator to a pleated filter medium. Fig. 7 is a schematic view of the air filter unit of Fig. 3 as seen from the direction of arrow p. Fig. 8 is a schematic vertical cross-sectional view of the cross-section X part of Fig. 4.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] 1 is a perspective view of an air conditioner 1 body used in an embodiment of the present invention. The air conditioner 1 body has a surface provided with an air intake port 42 (hereinafter referred to as the "air intake surface 41"), a surface provided with an air discharge port 44 (hereinafter referred to as the air discharge surface 43), and an internal fan.

[0013] The air conditioner 1 is a general household air conditioning system, and is not particularly limited in size. In this embodiment, the air conditioner 1 has dimensions of, for example, about 450 mm in length, about 800 mm in width, and about 280 mm in height.

[0014] 2 is a perspective view of an example in which an air filter unit 3 is installed in an air conditioner 1 used in an embodiment of the present invention. In this embodiment of the present invention, an air intake port 42 is provided on the top surface of the air conditioner 1 body. That is, in this embodiment, the top surface of the air conditioner 1 body serves as an air intake surface 41, and the air filter unit 3 is provided above the air intake surface 41. The air filter unit 3 may be provided either above or below the air intake surface 41. Here, providing the air filter unit 3 below the air intake surface 41 means that the air filter unit 3 is located inside the air conditioner 1 body.

[0015] 3 is a schematic perspective view of an air filter unit 3 in which a frame is arranged around a filter formed by adhering a separator to a pleated filter medium. The filter is formed by adhering a separator 52 to a pleated filter medium 51, and a frame 53 is arranged around the filter to form an integrated filter. The filter is composed of the pleated filter medium 51 and the separator 52, which is attached perpendicular to the ridges of the pleats formed on the filter medium 51.

[0016] Figure 4 is a schematic diagram of the air filter unit of Figure 3, viewed from the direction of arrow p. The filter is formed by fixing a separator 52 to a pleated filter medium 51, and the filter is integrated with a frame 53. Cross section X shows the cross section of the pleated filter medium at the point where the separator 52 is fixed to the filter medium 51.

[0017] Fig. 5 is a schematic longitudinal cross-sectional view of a filter provided with a separator, taken along the X-section of Fig. 4. The separator 52 is fixed to the pleated filter medium 51 in a direction perpendicular to the ridges of the peaks.

[0018] [Charged Nonwoven Fabric Filter Material] The charged nonwoven fabric filter material of the present invention has a QF value of 0.10 Pa at a wind speed of 6.5 m / min. －１ or more, and the QF value / filter material thickness is 0.18 Pa －１ / mm or more.

[0019] The QF value is an index of filtration performance, and is calculated using the following formula (1) using the collection efficiency η and the pressure loss P. The lower the pressure loss and the higher the collection performance, the higher the QF value, indicating that the filtration performance when the filter material is used in a filter is good. Formula (1) QF value = - [ln (1 - [η / 100] / P)] The charged nonwoven fabric filter material of the present invention has a QF value of 0.11 Pa at a wind speed of 6.5 m / min. －１ The QF value of the charged nonwoven fabric filter material is preferably 0.10 Pa or more. －１ If it is less than this, when it is installed in the air conditioner body and used to purify the air, the filtration performance will be low and the dust collection performance will be low.

[0020] The charged nonwoven fabric filter material of the present invention has a QF value / filter material thickness of 0.20 Pa －１ / mm or more is preferable, and 0.22 Pa－１ / mm or more is more preferable. －１ If the thickness is less than / mm, when an air filter unit is constructed using pleated filter media, an increase in pressure loss occurs due to the structure, and the dust collection performance decreases when the air filter unit is installed in the air conditioner body and used to purify the air.

[0021] The charged nonwoven fabric filter material of the present invention may be used as a single layer of the charged nonwoven fabric filter material alone, or may be used as a laminate of two or more layers, for example, with a support layer attached to the charged nonwoven fabric layer. By using a laminated structure, high filtration performance can be achieved. The support layer is a layer that maintains the pleated structure.

[0022] There are no particular restrictions on the material of the charged nonwoven fabric used in the charged nonwoven fabric layer, but examples of usable materials include polypropylene fibers, polyester fibers (PET fibers, etc.), vinylon fibers, polyamide fibers, ultra-high molecular weight polyethylene fibers, polyaramid fibers, carbon fibers, glass fibers, and metal fibers.

[0023] The structure of the charged nonwoven fabric is not particularly limited, but spunbond nonwoven fabric, needle-punched nonwoven fabric, melt-blown nonwoven fabric, etc. can be used. In order to achieve a high QF value, melt-blown nonwoven fabric is preferred. In order to achieve even higher collection performance, melt-blown nonwoven fabric made of polypropylene fibers is preferred. Furthermore, the nonwoven fabric is subjected to electret processing to produce a charged nonwoven fabric.

[0024] The electret processing method is not particularly limited, and can be arbitrarily selected from charging methods such as corona discharge, pure water suction, friction charging, and water spray.

[0025] The nonwoven fabric to be electret-processed may contain an additive to improve the charging effect of the electret processing. There are various additives available, but hindered amine and triazine additives are particularly preferred because they help maintain static electricity.

[0026] The charged nonwoven fabric may also contain a functional agent. There are no particular limitations on the functional agent, but activated carbon, silica gel, zeolite, gas-adsorbing porous material, antibacterial agent, antifungal agent, antiviral agent, antiallergen agent, fragrance, etc. can be used. The functional agent may be adhered to the filter material or contained inside the fibers, or in the case of a laminate of two or more layers, the functional agent may be sandwiched between the layers.

[0027] The basis weight of the charged nonwoven fabric is not particularly limited, but is preferably 5 g / m ２ ~500g / m ２ It is preferable that the density is 8 g / m ２ More preferably, 10 g / m or more ２ ~300g / m ２ It is more preferable that the density is 5 g / m ２ If the density is above 500 g / m, the collection performance of the filter medium can be fully demonstrated. ２ If the thickness is less than this, the thickness of the filter medium becomes more appropriate and an increase in pressure loss due to the structure of the pleated filter medium can be suppressed.

[0028] The support layer can be made of a thermally bonded nonwoven fabric, a chemically bonded nonwoven fabric, a needle-punched nonwoven fabric, a spunbonded nonwoven fabric, etc. From the viewpoint of the thickness of the filter medium and the ease of pleating, a chemically bonded nonwoven fabric is preferred.

[0029] The bending resistance of support layer is preferably 1300 μ N or more, more preferably 1500 μ N or more.If it is 1300 μ N or more, when it is made into air filter unit, it can suppress the increase of the pressure loss caused by structure.In addition, if it is 1300 μ N or more, the thickness of support layer can be made smaller, so that the thickness of filter material can be made smaller, and the value of QF value / filter material thickness can be made higher.

[0030] The method for producing a laminated structure of two or more layers of filter media is not particularly limited. They may simply be stacked and bonded via an adhesive such as a heat-sealing resin or a moisture-curing resin. Alternatively, the second layer may be fabricated directly on the first layer in an in-line process. The method for producing a laminated charged nonwoven fabric using the adhesive described above is preferred because the layers are less likely to peel off during pleating.

[0031] [Air filter unit] The air filter unit of the present invention is an air filter unit having a pleated filter material in which the charged nonwoven fabric filter material of the present invention is formed into a pleated shape, and a frame, wherein the thickness of the air filter unit is 20 mm or less, the fold height / pleat spacing of the pleated filter material is 3.0 to 10.0, and the QF value when the air speed at the filter opening is 1.1 m / s is 0.10 Pa －１ The present invention is characterized in that:

[0032] The air filter unit of the present invention is composed of a pleated filter material that has been folded in a zigzag shape and a frame that supports the filter material.The frame is not particularly limited, but from the viewpoint of handling, it is preferable that the frame is made of nonwoven fabric.The attachment position of the frame is preferably attached to two of the six sides of the periphery of the pleated filter material, that is, the left and right sides of the folding direction, or to four sides, that is, the left and right sides of the folding direction, as shown in Figure 4.

[0033] The thickness of the air filter unit is 20 mm or less. If the thickness of the air filter unit exceeds 20 mm, it will be difficult to install it in the internal space of the air conditioner main body.

[0034] The pleat shape is expressed as α / β, where the fold height is the peak height α in Figure 5 and the pleat spacing is the peak pitch β in Figure 5, and α / β is 3.0 to 10.0, preferably 4.0 to 10.0. If the pleat shape α / β exceeds 10.0, the filter media within the unit will overlap or the distance between the filter media will be too close, increasing the pressure loss of the air filter unit due to its structure. Furthermore, the intake air volume will decrease when the unit is installed in an air conditioner, resulting in reduced dust collection performance. If the pleat shape α / β is less than 3.0, the usable filtration area within the limited unit size will be small, and the fluid passage speed relative to the filtration area will increase, resulting in reduced removal and collection performance of substances from the fluid. Furthermore, the dust collection performance will be reduced when the air filter unit is installed in an air conditioner.

[0035] The process of folding the filter material into a zigzag shape is called pleating, and there are various pleating methods, such as the reciprocating method and the rotary method, and either method is acceptable.

[0036] The shape of the pleated filter medium is not particularly limited, but the distance between adjacent mountain folds and valley folds, that is, the fold height, can be adjusted as desired.

[0037] In order to maintain the spacing between the ridges of the pleats of the pleated filter material (peak pitch β) within the unit, a separator may be attached in a substantially linear manner, intersecting the ridges of the pleated filter material. The separator is preferably a resin, more preferably a thermoplastic resin. The thermoplastic resin can be selected arbitrarily, such as an olefin resin or an ethylene vinyl acetate resin. In particular, an olefin resin is preferred because it has moderately slow crystallization, excellent workability, high bonding strength, and little unpleasant odor.

[0038] The width of separator can be arbitrarily set within the range that maintains the function of separator, but is preferably 0.3mm or more and 3.0mm or less, and more preferably 0.5mm or more and 2.8mm or less.If it is 0.3mm or more, the adhesion of resin is more sufficient, and the retention of pleat interval is improved.If it is 3.0mm or less, the pressure loss caused by covering the ventilation surface of pleated filter material is suppressed.

[0039] The method of attaching separator is not particularly limited.For example, the resin in molten state is placed on the crest of the filter material that has been pleated in advance, and the filter material is folded while it is not completely solidified and still has bonding ability, so that the resins contact each other, and then the filter material is cooled while maintaining the folded shape, so that the resin is solidified, so that separator can be attached.Or, after attaching a frame to the pleated filter material, the resin in molten state is placed on the crest of the pleated filter material, or the resin in molten state is ejected linearly onto a metal plate with high releasability, and then the resin is transferred to the crest of the pleated filter material, so that separator can be attached.Separator can be attached continuously as shown in Figure 4, or can be attached discontinuously.

[0040] The air filter unit of the present invention has a QF value of 0.10 Pa when the wind speed at the filter opening is 1.1 m / s. －１ or more, 0.12 Pa －１It is preferable that the QF value of the air filter unit is 0.10 Pa or more. －１ If the filter width is less than this, the dust collection performance will be reduced when the unit is installed in the air conditioner body and used to purify the air. Here, the filter width refers to the surface facing the peaks of the pleated filter material.

[0041] The air filter unit of the present invention is preferably for installation in a home room air conditioner, and more preferably for installation in the air conditioner inlet of the home room air conditioner.

[0042] The type of home room air conditioner is not particularly limited as long as there is space to mount the air filter unit.

[0043] Some home room air conditioners are equipped with a mesh filter for removing dust at the air intake. The air filter unit of the present invention can be installed either upstream or downstream of the mesh filter. Installing it upstream of the mesh filter makes filter replacement easier. On the other hand, installing it downstream of the mesh filter makes it less likely to clog because dust has already been removed.

[0044] The air filter unit of the present invention may be of any size that can be attached to the air intake of a residential room air conditioner. When the coverage rate is the ratio of the area of ​​the air intake to the area of ​​the air filter opening, if the coverage rate is too high, the dust collection performance in one pass will be improved, but the suction air volume will decrease, resulting in a decrease in the original heating / cooling capacity. If the coverage rate is too low, the decrease in suction air volume can be prevented, but the filtering performance of the air filter unit will be difficult to achieve.

[0045] The present invention will be specifically described below using examples, in which the evaluation methods are as follows.

[0046] <Measurement of pressure loss of filter material and collection efficiency of particles with a particle size of 0.3 to 0.5 μm> The sheet to be evaluated was placed in a 0.01 mm opening. ２ The filter medium was set in a wind tunnel at 100°C, and air was passed through it at the rated wind speed to determine the initial pressure loss P1 of the filter medium. The pressure loss was measured by reading the differential pressure before and after evaluation using a manometer.

[0047] Next, particles (polystyrene) were generated from the upstream side using an atomizer, and the particles were fed through a static eliminator. The number of particles before and after the evaluation sheet was measured using a particle counter, and the collection efficiency η1 (%) was calculated using the following formula. The rated air speed was measured at 6.5 m / min, and the evaluation was based on the following criteria. Collection efficiency η1 = (1 - (C1 / C0)) x 100 C0 = number of particles with a particle size of 0.3 to 0.5 μm before passing through the evaluation sheet C1 = number of particles with a particle size of 0.3 to 0.5 μm after passing through the evaluation sheet <Filter medium QF value> The pressure loss P1 of the filter medium measured above and collection efficiency η1 were calculated using the following formula (1). QF value = -[ln(1 - [η / 100] / P)] Equation (1) <Measurement of pressure loss of air filter unit and collection efficiency of particles with a particle size of 0.3 to 0.5 μm> The air filter unit was set in an evaluation device conforming to JIS B9908 (2011) Type 1 test method, and air was allowed to flow at the rated air flow rate of the air filter to determine the initial pressure loss P2 of the air filter unit. The pressure loss was determined by reading the differential pressure before and after the evaluation using a manometer.

[0048] Next, particles (KCl) generated by an atomizer were supplied from the upstream side, and the number of particles before and after the evaluation air filter unit was measured using a particle counter, and the collection efficiency η2 (%) was calculated using the following formula. ３ / min (air speed 1.1 m / sec) and evaluated according to the following criteria: Collection efficiency η2 = (1 - (C1 / C0)) x 100 C0 = number of particles with a particle size of 0.3 to 0.5 μm before passing through the evaluated air filter unit C1 = number of particles with a particle size of 0.3 to 0.5 μm after passing through the evaluated air filter unit <Air filter unit QF value> Using the pressure loss P2 and collection efficiency η2 of the air filter unit measured above, the QF value was calculated using the formula (1) used to calculate the filter medium QF value described above.

[0049] <Filter Medium Thickness> The thickness of the sheet to be evaluated was measured using a dial thickness gauge (TECLOCK SM-114, probe shape 10 mmφ, graduation 0.01 mm, measuring force 2.5 N or less). Measurements were taken at four locations, and the average value was used.

[0050] <Bending resistance of support layer> The bending resistance was evaluated in accordance with JIS L1085 (1998) 6.10.3 Gurley method, using a Gurley type bending resistance tester for a sample having a width of 25 mm and a length of 90 mm. The number of evaluations was set to 5, and the average value was calculated.

[0051] <Fold height> The fold height was measured by removing the frame from the unit (at positions before and after the pleating direction), and measuring the ridge height α at a position within 2.54 cm (1 inch) from the frame by placing a vernier caliper perpendicular to the ridge of the ridge of the pleated filter material to which no separator was attached.

[0052] <Pleat spacing> A metal ruler is placed on the ridgeline perpendicular direction of the ridges between the separators of the pleated filter material, and 10 ridges are measured. The measured value is equivalent to 9 data of ridge pitch β, and one data is calculated to be the pleat spacing. When a separator is not installed, one place near the frame and one place in the center of the ridgeline perpendicular direction of the ridges of the pleated filter material are measured using the above method, and the average value of the calculated values ​​is taken as the pleat spacing.

[0053] <Space purification capacity (CADR)> Tests were conducted in accordance with JEMA1467. Evaluation room (25m ３ A room air conditioner (Airest room air conditioner manufactured by Sharp) equipped with an air filter unit and a digital dust concentration meter (LD-5D manufactured by SHIBATA) were set up in the room. Five cigarettes were smoked simultaneously, and after the dust concentration stabilized, the air conditioner was operated in air purification mode (Plasmacluster OFF, maximum airflow level). The dust concentration was monitored continuously for 60 minutes, and the CADR (Clean Air Delivery Rate) [m ３ / hour] was calculated.

[0054] Example 1 An electrically charged nonwoven fabric filter medium has a first layer (support layer) made of a short fiber nonwoven fabric made of glass fiber, polyester fiber, pulp, vinylon fiber, and a binder, and a second layer (electrically charged nonwoven fabric layer) made of an electret melt-blown nonwoven fabric made of polypropylene fiber, and the two layers are bonded together with a polyethylene resin. The thickness of the filter medium is 0.41 mm, and the basis weight is 55 g / m ２The bending resistance of the support layer was 2200 μN. The QF value calculated from the pressure loss P1 of the filter medium and the collection efficiency η1 was 0.12 Pa. －１ The QF value / thickness is 0.29 Pa. －１ / mm.

[0055] The pleating process applied to the charged nonwoven fabric filter material was processed so that the pleated filter material had a folding height of 18.0 mm, and was cut with 135 ridges. An olefin resin separator was applied to the front and back of the pleated filter material at 5.08 cm intervals (2 inch intervals) in the ridge direction of the pleated filter material, and then folded again. A frame was attached to four sides of the pleated filter material with adhesive, and the air filter unit was molded into an approximately rectangular parallelepiped with a length of 326 mm, a width of 303 mm, and a height of 20 mm. Since the height was 20 mm, the thickness of the air filter unit was also 20 mm. In addition, the pleated structure had a ridge height α of 18.0 mm, a ridge pitch β of 2.4 mm (324 / 135), and a pleat shape α / β = 7.5. The QF value calculated from the pressure loss P2 and collection efficiency η2 of the air filter unit was 0.14 Pa. －１ It was.

[0056] Furthermore, when the air filter unit was installed in a room air conditioner (Airest manufactured by Sharp), the CADR in the space purification capacity test was 324m ３ The results are shown in Table 1.

[0057] <Example 2> The charged nonwoven fabric filter material is the same as in Example 1, and the pleating process is performed so that the pleated filter material has a folded height of 18.0 mm and is cut with 90 ridges. An olefin resin separator is attached to the front and back of the pleated filter material at intervals of 5.08 cm (2 inch intervals) in the ridge direction of the pleated filter material, and then folded again. A frame is attached to four sides of the pleated filter material with adhesive, and the air filter unit is molded into an approximately rectangular parallelepiped with a length of 326 mm, a width of 303 mm, and a height of 20 mm. Since the height is 20 mm, the thickness of the air filter unit is also 20 mm. In addition, the pleat structure has a peak height α of 18.0 mm, a peak pitch β of 3.6 mm (324 / 90), and a pleat shape α / β = 5.0. The QF value of the air filter unit is 0.12 Pa. －１ The CADR in the space purification capacity test was 329m３ The results are shown in Table 1.

[0058] <Example 3> The charged nonwoven fabric filter material is the same as in Example 1, and the pleating process is performed so that the pleated filter material has a folded height of 18.0 mm and is cut with 180 ridges. An olefin resin separator is applied to the front and back of the pleated filter material at intervals of 5.08 cm (2 inch intervals) in the ridge direction of the pleated filter material, and then folded again. A frame is attached to the four sides of the pleated filter material with adhesive, and the air filter unit is molded into an approximately rectangular parallelepiped with a length of 326 mm, a width of 303 mm, and a height of 20 mm. Since the height is 20 mm, the thickness of the air filter unit is also 20 mm. In addition, the pleat structure has a peak height α of 18.0 mm, a peak pitch β of 1.8 mm (324 / 180), and a pleat shape α / β = 10.0. The QF value of the air filter unit is 0.12 Pa. －１ The CADR in the space purification capacity test was 313m ３ The results are shown in Table 1.

[0059] <Example 4> The charged nonwoven fabric filter material was the same as in Example 1, and the pleating was performed so that the pleated filter material had a folded height of 13.5 mm and was cut with 135 ridges. An olefin resin separator was attached to the front and back of the pleated filter material at 5.08 cm intervals (2 inch intervals) in the ridge direction of the pleated filter material, and then folded again. A frame was attached to the four sides of the pleated filter material with adhesive, and the air filter unit was molded into an approximately rectangular parallelepiped with a length of 326 mm, a width of 303 mm, and a height of 15 mm. Since the height was 15 mm, the thickness of the air filter unit was also 15 mm. In addition, the pleated structure had a peak height α of 13.5 mm, a peak pitch β of 2.4 mm (324 / 135), and a pleat shape α / β = 5.6. The QF value of the air filter unit was 0.10 Pa. －１ The CADR based on the space purification capacity test was 286m ３ The results were good, at 1 / hour. These results are shown in Table 1. Example 5 The first layer (support layer) of the charged nonwoven fabric filter medium was a core-sheath composite spunbond nonwoven fabric (basis weight 70 g / m) made of polypropylene. ２The second layer (charged nonwoven fabric layer) is an electret melt-blown nonwoven fabric (basis weight 8 g / m) made of polypropylene fiber. ２ After the first layer was produced, a second layer was laminated in-line to obtain a charged nonwoven fabric filter medium. The filter medium had a thickness of 0.61 mm and a basis weight of 78 g / m ２ The bending resistance of the support layer was 2800 μN. The QF value calculated from the pressure loss P1 of the filter medium and the collection efficiency η1 was 0.12 Pa. －１ The QF value / thickness is 0.20 Pa. －１ / mm.

[0060] The pleating process applied to the charged nonwoven fabric filter material was processed so that the pleated filter material had a folded height of 18.0 mm, and was cut with 135 pleats. An olefin resin separator was applied to the front and back of the pleated filter material at 5.08 cm intervals (2 inch intervals) in the ridge direction of the pleated filter material, and then folded again. A frame was attached to the four sides of the pleated filter material with adhesive, and the air filter unit was molded into an approximately rectangular parallelepiped with a length of 326 mm, a width of 303 mm, and a height of 20 mm. Since the height was 20 mm, the thickness of the air filter unit was also 20 mm. In addition, the pleated structure had a peak height α of 18.0 mm, a peak pitch β of 2.4 mm (324 / 135), and a pleat shape α / β = 7.5.

[0061] The QF value of the air filter unit is 0.10 Pa. －１ The CADR in the space purification capacity test was 251m ３ The results are shown in Table 1.

[0062] <Comparative Example 1> The charged nonwoven fabric filter medium has a first layer (support layer) made of a short fiber nonwoven fabric made of polyester fibers and polyester-based binder fibers, and a second layer (charged nonwoven fabric layer) made of an electret melt-blown nonwoven fabric made of polypropylene fibers, and the two layers are bonded together with a polyethylene resin. The collection efficiency of this filter medium is 20%, the thickness is 0.50 mm, and the basis weight is 107 g / m ２ The bending resistance of the support layer was 10,000 μN. The QF value calculated from the pressure loss P1 of the filter medium and the collection efficiency η1 was 0.08 Pa. －１ The QF value / thickness is 0.16 Pa. －１ / mm.

[0063] The pleating applied to the charged nonwoven fabric filter material and the structure of the air filter unit were the same as in Example 1. The QF value of the air filter unit was 0.03 Pa. －１ The CADR in the space purification capacity test is 78m ３ The results are shown in Table 1.

[0064] Comparative Example 2: The charged nonwoven fabric filter medium has a first layer (support layer) made of a short fiber nonwoven fabric made of glass fiber, polyester fiber, pulp, vinylon fiber, and a binder, and a second layer (charged nonwoven fabric layer) made of an electret melt-blown nonwoven fabric made of polypropylene fiber, and the two layers are bonded together with a polyethylene resin. The thickness of the filter medium is 0.45 mm, and the basis weight is 65 g / m. ２ The bending resistance of the support layer was 3300 μN. The collection efficiency η1 of the filter medium was 99.97%, but the QF value calculated from the pressure loss P1 of the filter medium and the collection efficiency η1 was 0.08 Pa. －１ The QF value / thickness is 0.18 Pa. －１ / mm.

[0065] The pleating applied to the charged nonwoven fabric filter material and the structure of the air filter unit were the same as in Example 1. The QF value of the air filter unit was 0.08 Pa. －１ The CADR in the space purification capacity test was 156m ３ The results are shown in Table 1.

[0066] Comparative Example 3: The charged nonwoven fabric filter medium has a first layer (support layer) made of a short fiber nonwoven fabric made of polyester fibers and polyester-based binder fibers, and a second layer (charged nonwoven fabric layer) made of an electret melt-blown nonwoven fabric made of polypropylene fibers, and the two layers are bonded together with a polyethylene resin. The filter medium has a thickness of 0.75 mm and a basis weight of 105 g / m ２ The bending resistance of the support layer was 10,000 μN. The QF value calculated from the pressure loss P1 and collection efficiency η1 of the filter medium was 0.12 Pa. －１ The QF value / thickness is 0.16 Pa. －１ / mm.

[0067] The pleating applied to the charged nonwoven fabric filter material and the structure of the air filter unit were the same as in Example 1. The QF value of the air filter unit was 0.10 Pa. －１ The CADR in the space purification capacity test is 188m ３ The results are shown in Table 1.

[0068] <Reference Example 1> The charged nonwoven fabric filter material is the same as in Example 1, and the pleating process carried out on the charged nonwoven fabric filter material is processed so that the pleated filter material has a folded height of 18.0 mm, and is cut with 36 peaks.A frame is attached to the four sides of the pleated filter material with adhesive, and the size of the air filter unit is molded into a roughly rectangular parallelepiped with a length of 326 mm, a width of 303 mm, and a height of 20 mm.Because the height is 20 mm, the thickness of the air filter unit is also 20 mm.In addition, the pleat structure has a peak height α of 18.0 mm, a peak pitch β of 9.0 mm (324 / 36), and a pleat shape α / β=2.0.The QF value of the air filter unit is 0.05 Pa. －１ The CADR in the space purification capacity test was 172m ３ The results are shown in Table 1.

[0069] <Reference Example 2> The charged nonwoven fabric filter material is the same as in Example 1, and the pleating process carried out on the charged nonwoven fabric filter material is processed so that the pleated filter material has a folded height of 18.0 mm, and is cut with 270 peaks.A frame is attached to the four sides of the pleated filter material with adhesive, and the size of the air filter unit is molded into a roughly rectangular parallelepiped with a length of 326 mm, a width of 303 mm, and a height of 20 mm.Because the height is 20 mm, the thickness of the air filter unit is also 20 mm.In addition, the pleat structure has a peak height α of 18.0 mm, a peak pitch β of 1.2 mm (324 / 270), and a pleat shape α / β=15.0.The QF value of the air filter unit is 0.05 Pa. －１ The CADR in the space purification capacity test is 165m ３ The results are shown in Table 1.

[0070]

[0071] REFERENCE SIGNS LIST 1 Air conditioner 2 Air conditioner with air filter unit installed 3 Air filter unit 41 Air intake surface 42 Air intake port 43 Air discharge surface 44 Air discharge port 51 Filter material 52 Separator 53 Frame p: Direction X: Cross section α: Peak height (fold height of pleated filter material) β: Peak pitch (pleat interval)

Claims

1. QF value is 0.10 Pa at a wind speed of 6.5 m / min. －１ or more, and the QF value / filter material thickness is 0.18 Pa －１ / mm or more.

2. The charged nonwoven fabric filter medium according to claim 1, characterized in that it has at least a charged nonwoven fabric layer and a support layer.

3. The charged nonwoven fabric filter medium according to claim 2, characterized in that the bending resistance of the support layer is 1300 μN or more.

4. An air filter unit comprising a pleated filter material in which the electrically charged nonwoven fabric filter material according to any one of claims 1 to 3 is pleated, and a frame, wherein the thickness of the air filter unit is 20 mm or less, the fold height / pleat spacing of the pleated filter material is 3.0 to 10.0, and the QF value when the air velocity at the filter opening is 1.1 m / s is 0.10 Pa. －１ The air filter unit is characterized by the above.

5. The air filter unit according to claim 4, which is mounted on a home room air conditioner.

6. The air filter unit according to claim 5, which is to be mounted on the air intake of a home room air conditioner.

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