JP5978460B2 - AIR FILTER, AIR CLEANING APPARATUS HAVING THE AIR FILTER, AND ITS MANUFACTURING METHOD - Google Patents

Description

  The present invention relates to an air filter incorporated in an air conditioner and the like, an air cleaning device including the air filter, and a method for manufacturing the air filter.

  A conventional air filter has a structure in which an upper layer, an intermediate layer, a lower layer, and a fiber having a large fiber diameter are sequentially laminated into thin fibers when viewed from the windward side (for example, see Patent Document 1).

JP 2011-89226 A

  The problem in the conventional example is that the filter life is short.

  That is, as the fiber diameter of each layer is reduced in order to improve the initial collection performance, the pressure loss increases with long-term use, and the user is forced to replace the filter within several years.

  Therefore, the present invention has an object of maintaining a high dust collection performance and suppressing an increase in pressure loss even in long-term use.

In order to achieve this object, the present invention includes a base material portion and a fiber layer provided on the surface of the base material portion, and the fiber layer has a fiber diameter of mainly 600 nm or more and less than 1000 nm . 1 nanofiber assembly and a second nanofiber assembly having a fiber diameter smaller than that of the first nanofibre assembly, and the second nanofiber assembly on the substrate portion side of the fiber layer. A fiber assembly is arranged, and the basis weight of the first nanofiber assembly is set to be greater than the basis weight of the second nanofiber assembly while the basis weight of the first nanofiber assembly is set to 0. 0. An air filter characterized by being 6 or more and less than 2.5 g / m ² , thereby achieving the object.

As described above, the present invention includes a base part and a fiber layer provided on the surface of the base part, and the fiber layer has a first nanofiber whose fiber diameter is mainly 600 nm or more and less than 1000 nm. An assembly and a second nanofiber assembly having a smaller fiber diameter than the first nanofibre assembly, and the second nanofiber assembly on the substrate portion side of the fiber layer And the basis weight of the first nanofiber aggregate is made larger than the basis weight of the second nanofiber aggregate, and the basis weight of the first and second nanofiber aggregates is 0.6 or more. It is an air filter characterized by being less than 5 g / m ^2, can maintain dust collection performance in a high state, and can suppress an increase in pressure loss even in long-term use.

  That is, in the present invention, the second nanofiber aggregate formed by thin nanofibers ensures high dust collection performance while reducing the initial pressure loss, and is formed by nanofibers thicker than the basis weight. By increasing the basis weight of 1 nanofiber aggregate, the amount of voids in the fiber layer can be secured, and the increase in pressure loss can be suppressed while collecting a large amount of dust during long-term use. .

The block diagram which shows the cross section of the air purifying apparatus provided with the air filter which shows embodiment of this invention Perspective view of the air filter The block diagram which shows the expanded section of the filter material part Schematic showing the manufacturing method of the air filter The graph which shows the relationship between the void | hole amount and the pressure loss increase rate in the Example of this invention

The air filter according to claim 1 of the present invention includes a base material portion and a fiber layer provided on the surface of the base material portion, and the fiber layer has a fiber diameter dimension mainly of 600 nm or more and less than 1000 nm . 1 nanofiber assembly and a second nanofiber assembly having a fiber diameter smaller than that of the first nanofibre assembly, and the second nanofiber assembly on the substrate portion side of the fiber layer. A fiber assembly is arranged, and the basis weight of the first nanofiber assembly is set to be greater than the basis weight of the second nanofiber assembly while the basis weight of the first nanofiber assembly is set to 0. 0. 6 or more and less than 2.5 g / m ² .

The fiber diameter dimension indicates the center fiber diameter, but the fiber diameter has a substantially normal distribution and has a variation with respect to the center fiber diameter, so it is described as “mainly”.

  Thin nanofibers have a lower pressure loss than the thicker ones in specifications that exhibit the same dust collection performance. This is because the resistance during ventilation is small. However, since dust is collected in a planar shape by the fibers existing in a mesh shape, the pressure loss is remarkably increased when a large amount of dust is collected. On the other hand, dust collection performance can be obtained by stacking thick nanofibers. At this time, the pressure loss is higher than that of the thin nanofibers, but since the fibers are present in a laminated state, that is, with gaps in the thickness direction, a space for storing dust can be obtained.

  In the case where the basis weight of the first nanofiber aggregate is larger than the basis weight of the second nanofiber aggregate, high dust collection performance is secured while reducing the initial pressure loss, and in the fiber layer. By ensuring the amount of voids, it was possible to suppress an increase in pressure loss while collecting a large amount of dust during long-term use.

The second nanofiber aggregate has a fiber diameter of mainly 200 nm or more and less than 400 nm, thereby ensuring high dust collection performance while reducing the initial pressure loss, and the amount of voids in the fiber layer. As a result, it is possible to suppress an increase in pressure loss while collecting a large amount of dust during long-term use. The fiber diameter dimension indicates the center fiber diameter, but the fiber diameter has a substantially normal distribution and has a variation with respect to the center fiber diameter, so it is described as “mainly”.

  In addition, by providing a protective layer on the opposite side of the first nanofiber assembly to the base portion side, the first nanofiber assembly is prevented from being damaged by an external impact. In the second nanofiber assembly, the base material portion serves as a protective layer.

In addition, since the fiber layer is laminated so as to have a gap of 6 × 10 ⁻⁶ m ³ / m ² or more, a sufficient space for storing dust is obtained, and high dust collection performance while reducing initial pressure loss As well as ensuring the amount of voids in the fiber layer, it is possible to suppress an increase in pressure loss while collecting a large amount of dust during long-term use.

  Moreover, it is an air purification apparatus provided with the inlet port, the air filter, the ventilation means, and the exhaust port, Comprising: The said air filter is an air filter as described in any one of Claim 1 to 4, The fiber layer of the said air filter The air purifying device characterized in that the air purifying device is disposed on the windward side from the base material portion, and is formed from the windward side with the protective layer, the first nanofiber assembly formed of thick nanofibers, and the thin nanofibers when ventilated. It becomes the order of the 2nd nanofiber aggregate and a substrate. Since the first nanofiber assembly formed of thick nanofibers exists upstream of the second nanofiber assembly, most of the dust is trapped upstream, and the second nanofiber assembly is moved to the second nanofiber assembly. The load can be reduced. Thereby, it can suppress that dust is collected in the shape of a plane by thin nanofiber, and can suppress a raise of pressure loss in long-term use. Furthermore, by providing the base material on the most downstream side, it is possible to suppress a decrease in dust collection performance due to the fiber layer being detached, and long-term use is possible.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1, the air purifier including the air filter of this embodiment includes a blower 2 and an air filter 3 in a main body case 1. The main body case 1 has a substantially vertically long box shape. The main body case 1 is provided with a substantially square-shaped intake port 4 on the front side surface portion thereof, and the main body case 1 is provided with a substantially square-shaped exhaust port 5. Yes. The exhaust port 5 is provided with a wind direction louver 6.

  The air blowing means 2 is provided in an air passage between the air inlet 4 and the air outlet 5 of the main body case 1, and has a scroll-shaped casing 7 and a blade 8 which is a centrifugal air fan provided in the casing 7. And the electric motor 9 that rotates the blade 8. The air filter 3 is located inside the main body case 1 of the air inlet 4 of the main body case 1. The room air sucked into the main body case 1 from the air inlet 4 by the air blowing means 2 is sent to the air outlet 5 through the air filter 3. That is, the indoor air is cleaned by the air filter 3 and blown into the room.

  As shown in FIG. 2, the air filter 3 includes a pleat-shaped filter medium portion 10 and a frame shape provided on the outer periphery of the filter medium portion 10 to hold the filter medium portion 10 in a pleat shape, or a shape holding portion such as an adhesive member. 11. As shown in FIG. 3, the filter medium part 10 includes a base material part 12, a fiber layer 13 provided on the upstream side surface of the air flow blown to the base material part 12, and protection for protecting the fiber layer 13. It is composed of layer 14. The fiber layer 13 includes a first nanofiber assembly 13a and a second nanofiber assembly 13b.

The basis weight of the base material portion 12 is preferably 10 to 100 g / m ² . When the basis weight is less than 10 g / m ² , the rigidity of the base material portion 12 is lowered, and thus the productivity of pleating process is lowered and it is difficult to maintain the filter shape.

  Moreover, it is preferable that the average fiber diameter of the base material part 12 is 1-50 micrometers. When the average fiber diameter is less than 1 μm, the strength of the single fiber is low and the strength as a reinforcing material is insufficient. When the average fiber diameter is 50 μm or more, the thickness of the base material portion 12 is increased, and the structural pressure due to pleating is increased. Since loss increases, it is not preferable. As the base material part 12, since it needs to have air permeability in order to function as a filter medium of the air filter 3, for example, a spunbond nonwoven fabric, a thermal bond nonwoven fabric, a melt blown nonwoven fabric, or papers can be used.

  The fiber layer 13 includes a first nanofiber assembly 13a formed of thick nanofibers and a second nanofiber assembly 13b formed of thin nanofibers. The first nanofiber aggregate 13a preferably has a fiber diameter of mainly 600 nm to 1000 nm, and the second nanofiber aggregate 13b preferably has a fiber diameter of mainly 200 nm to 400 nm.

  The air flows in the order of the protective layer 14, the first nanofiber aggregate 13 a, the second nanofiber aggregate 13 b formed of thin nanofibers, and the base material portion 12. Since the first nanofiber aggregate 13a is located on the windward side and collects large dust, it is not preferable that the fiber diameter is less than 600 nm because the increase in pressure loss in long-term use becomes large. When the thickness is 1000 nm or more, the low pressure loss and high dust collection performance characteristics of the nanofiber are deteriorated.

  Also, since the second nanofiber aggregate 13b mainly collects small dust, it is not preferable that the fiber diameter is 400 nm or more because the dust collection performance is lowered, and if it is less than 200 nm, there are voids. This is not preferable because it tends to be clogged, the increase in pressure loss during long-term use becomes large, and a sufficient space in the fiber layer for storing dust cannot be obtained.

The voids in these two types of fiber layers as a whole are set to 6 × 10 ⁻⁶ m ³ / m ² or more, so that a large amount of dust can be collected and the dust collection performance can be maintained at a high level. Also, the increase in pressure loss can be suppressed. Details will be described in Examples.

  In order to prevent the fiber layer 13 from being damaged, the protective layer 14 is provided on the surface side (windward side) of the fiber layer 13. As an example of the material of the protective layer 14, the same material as the base material may be used, or a heat-meltable resin nonwoven fabric may be used. When a heat-meltable nonwoven fabric is used, the effect that the fiber layer 13 can be fixed by heating is obtained. When the fiber layer 13 is firmly fixed to the base member 12 by strong electrostatic force or physical adhesion, or when it is not subjected to external impacts in the manufacturing process or use environment, the protective layer 14 is necessarily provided. There is no need.

  The base member 12 and the protective layer 14 preferably have a pressure loss of about 1 to 10 Pa when air is introduced at a surface wind speed of 5.3 cm / sec, for example. If the pressure loss is 10 Pa or more, the pressure loss of the air filter 3 is increased, the inflow of air is hindered, and the effect of reducing the pressure loss by using nanofibers is reduced, which is not preferable.

  The feature in this embodiment is that the fiber layer 13 provided on the surface of the base material portion 12 includes a first nanofiber assembly 13a formed of thick nanofibers and a second nanofiber assembly 13b formed of thin nanofibers. And the second nanofiber aggregate 13b is disposed on the base material part 12 side of the fiber layer 13, and the basis weight of the first nanofiber aggregate 13a is set to the second nanofiber aggregate. That is, the weight per unit area is larger than 13b.

  In other words, in the present invention, the first nanofiber aggregate 13a formed of thick nanofibers provided on the windward side collects coarse dust in the air, and thereby the second nanofibers formed of thin nanofibers are collected. The load on the fiber assembly 13b can be reduced.

  In an assembly of thin nanofibers, dust is collected in a planar shape by fibers present in a mesh shape, and therefore, when a large amount of dust is collected, the pressure loss is significantly increased. On the other hand, dust collection performance can be obtained by stacking thick nanofibers. At this time, the pressure loss is higher than that of the thin nanofibers, but since the fibers are present in a laminated state, that is, with gaps in the thickness direction, a space for storing dust can be obtained.

  However, generally, when thick fibers and thin fibers are sprayed so as to have the same weight per unit area, if the materials are the same, the number of fibers occupying per unit volume is larger with fine fibers, and voids are larger. Get smaller. As a result, the structure becomes dense and high dust collection performance can be obtained at the beginning. However, in long-term use, the air gap is gradually blocked, the pressure loss increases, and the performance as an air filter decreases, which is disadvantageous.

  Therefore, if the basis weight of the first nanofiber aggregate 13a formed of thick nanofibers is made larger than the basis weight of the second nanofiber aggregate 13b formed of thin nanofibers, the initial pressure is increased by the thin nanofibers. High dust collection performance is secured while reducing loss, and the amount of voids in the fiber layer is secured with thick nanofibers, making it possible to suppress an increase in pressure loss while collecting a large amount of dust during long-term use. Become.

(Embodiment 2)
An example of the manufacturing method of the air filter 3 will be described with reference to FIG.

  As shown in FIG. 4, the manufacturing facility is equipped with a conveying means 15 that carries the substrate portion 12 and conveys it in the horizontal direction, nozzles 16 and 17 positioned above the conveying means 15, and a position below the conveying means 15. It is comprised from the electrode plate 18 to do.

  The nozzle 16 sprays a polymer solution in order to form the second nanofiber aggregate 13b on the surface that is the upper surface of the flat substrate portion 12 conveyed by the conveying means 15. The nozzle 17 sprays a polymer solution in order to form the first nanofiber aggregate 13a on the upper surface of the second nanofiber aggregate 13b transported by the transport means 15.

  The material of the high molecular polymer may be any material that can be made into a solution. For example, a polymer such as PAN (polyacrylonitrile), PVDF (polyvinylidene fluoride), PVA (polyvinyl alcohol), polyvinyl acetate (PVAc), PES (polyether sulfone), polyurethane, nylon, etc. is dissolved in a suitable organic solvent. Can be made into a solution.

  In the manufacture of the air filter 3, first, while the flat plate-shaped base material portion 12 is transported by the transport means 15, a polymer solution is used to form the second nanofiber aggregate 13 b from the nozzle 16. Release towards. Here, a voltage of about +20 KV is applied to the nozzle 16, and the conveying means 15 is grounded via the electrode plate 18. Due to this potential difference, the polymer solution released from the nozzle 16 causes the base material portion to It adheres to 12 surfaces. Next, in order to form the first nanofiber aggregate 13a from the nozzle 17, the polymer solution is discharged toward the surface of the second nanofiber aggregate 13b. A voltage of about +20 KV is also applied to the nozzle 17, and the polymer solution released from the nozzle 17 adheres to the surface of the second nanofiber assembly 13 b due to the potential difference, thereby forming the first nanofiber assembly 13 a. To do.

  By adopting such a configuration, for example, even when adjusting the void amount by changing the basis weight of each of the two types of nanofiber aggregates, the number of nozzles is added or the discharge amount of the polymer solution is increased. Manufacture can be easily performed only by changing the manufacturing process without greatly changing the manufacturing process.

A dust collection filter medium was prepared by the air filter manufacturing method shown in the second embodiment. One type selected from a solution in which PES (polyethersulfone) is dissolved in DMAc (dimethylacetamide) at a ratio of 18 wt% to 25 wt% with respect to glass paper (Hokuetsu Kishu Paper: H-720) as the base material portion 12. Was spun to form a second nanofiber assembly 13b. On top of this, one type selected from a solution in which PES was dissolved in DMAc at a rate of 27 wt% or 30 wt% was spun to form a first nanofiber assembly 13a. At this time, the basis weight of each nanofiber aggregate was arbitrary in the range of 0.3 to 2.5 g / m ² . Furthermore, a dust-collecting filter medium was obtained by overlaying a melt-blown nonwoven fabric (Tapyrus: P010SW-00X) as a protective layer 14 thereon.

  About these dust collection filter media, the void amount was calculated as follows. First, the weight was measured about the glass paper used as a base material. At the same time, the thickness of a plurality of locations was measured using a digital micrometer (SONY: M-30), and the thickness of the glass paper was calculated from the average value. Next, the weight of the first nanofiber assembly 13a was measured, and the weight of the first nanofiber assembly 13a was calculated by subtracting the weight of the glass paper. At the same time, the thickness in this state was measured at a plurality of locations using the above-mentioned digital micrometer, and the thickness of the first nanofiber aggregate 13a was calculated by subtracting the thickness of the glass paper from the average value. Similarly, the basis weight and thickness of the second nanofiber aggregate 13b were calculated.

Next, using the “thickness”, “weight per unit area”, and “specific gravity of PES (1.4)” obtained for each nanofiber assembly, the porosity in the fiber deposition state of each fiber diameter was calculated. Furthermore, from this “porosity”, the void amount (unit: m ³ / m ² ) in the fiber layer of the dust collecting filter medium was calculated.

  Each dust collection filter medium had a sample size of 12 cm × 12 cm, and measured initial values of dust collection performance and pressure loss at a surface wind speed of 5.3 cm / sec. Among them, a particle collection performance of about 96% is selected for particles having a particle size of 0.3 μm, and the dust is collected in an accelerated manner by sucking the dust of tobacco (mild seven 10 mg) therein. . The pressure loss at the surface wind speed of 5.3 cm / sec after spreading and sucking five cigarettes was measured, and the rate of increase relative to the initial value was calculated. The result is shown in FIG. The horizontal axis represents the amount of voids of the fiber layer 13 in the dust collection filter medium, and the vertical axis represents the rate of increase in pressure loss before and after sucking tobacco.

In FIG. 5, there is an inflection point in the relationship between the void amount and the pressure loss increase rate. That is, it was revealed that the pressure loss was significantly increased when the void amount was smaller than 6 × 10 ⁻⁶ m ³ / m ² .

  This generally includes a large number of second nanofiber aggregates 13b made of fine nanofibers in the fiber layer 13. From this, the first nanofiber aggregate formed by thick nanofibers while ensuring high dust collection performance while reducing the initial pressure loss by the second nanofiber aggregate formed by thin nanofibers. By ensuring the amount of voids in the fiber layer by 13a and determining the amount of voids based on the basis weight and the fiber diameter, it becomes clear that an increase in pressure loss can be suppressed while collecting a large amount of dust in long-term use. It was.

  As described above, the present invention can suppress an increase in pressure loss even during long-term use.

  Therefore, it is expected to be utilized as an air filter for home use or office use, a method for manufacturing the air filter, and an air purifier equipped with the air filter.

DESCRIPTION OF SYMBOLS 1 Main body case 2 Air blowing means 3 Air filter 4 Intake port 5 Exhaust port 6 Wind direction louver 7 Casing 8 Blade 9 Electric motor 10 Filter medium part 11 Shape holding part 12 Base material part 13 Fiber layer 13a 1st nanofiber aggregate 13b 2nd Nanofiber assembly 14 Protective layer 15 Conveying means 16, 17 Nozzle 18 Electrode plate

Claims (5)

A substrate layer and a fiber layer provided on the surface of the substrate portion, wherein the fiber layer has a first nanofiber aggregate whose fiber diameter is mainly 600 nm or more and less than 1000 nm ; and the first A second nanofiber assembly having a fiber diameter smaller than that of the nanofibre assembly, and the second nanofiber assembly is disposed on the substrate portion side of the fiber layer, whereby the first nanofiber The basis weight of the aggregate is made larger than the basis weight of the second nanofiber aggregate, and the basis weight of the first and second nanofiber aggregates is 0.6 or more and less than 2.5 g / m ^2. An air filter characterized by 2. The air filter according to claim 1, wherein the second nanofiber aggregate has a fiber diameter of mainly 200 nm or more and less than 400 nm. The air filter according to claim 1 or 2, wherein a protective layer is provided on the opposite side of the first nanofiber assembly to the base portion side. Air filter according to claim 1, any one of 3, characterized in that the fibrous layer is laminated to have a ^{6 × 10 -6 m 3 / m} 2 or more voids. The air purification apparatus having an intake port and the air filter and the blowing means and the outlet, wherein the air filter is an air filter according to any one of claims 1 to 4, the fibrous layer of the air filter An air purifier arranged on the windward side of the base material.

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