Filter medium and filter element

Abstract

Provided are a filter medium and a filter element that have a long service life, and in which a pressure loss does not easily increase rapidly and a large amount of unnecessary matter such as mist and dust can be collected up to a predetermined pressure loss.　A filter medium according to the present invention includes: a three-dimensional net-like structure that is composed of linear bodies having an average diameter of 100 μm or more and has raised sections in which the linear bodies are peak-shaped and depressed sections in which the linear bodies are valley-shaped; and a nonwoven fabric having a bulk density of 25 kg / m3 or less or a thickness of 8 mm or more. The height of the raised sections is 6 mm or more.

Description

Filter media and filter elements

[0001] The present invention relates to a filter material capable of removing unwanted substances from a fluid, preferably a filter material capable of removing mist from a gas containing mist, and more particularly to a filter material capable of removing mist from a gas containing paint mist. Furthermore, the invention also relates to a filter element equipped with this filter material.

[0002] Conventionally, various filter materials have been proposed that can remove unwanted substances such as mist and dust contained in fluids such as liquids and gases.

[0003] For example, when painting automobiles or other vehicles, if the excess paint mist generated during this process is exhausted, it will pollute the outside air. Therefore, air containing paint mist is passed through a filter element to capture the paint mist, remove it, and then exhaust the air.

[0004] As such filter elements, a combination of a paper mist separator, a nonwoven fabric auxiliary filter, and a nonwoven fabric medium-high performance filter is known (Patent Document 1). However, with such conventional filter elements, a paint film forms as paint mist collection continues, causing a rapid increase in pressure loss. As a result, the amount of paint mist that can be collected up to a predetermined pressure loss is small, and the lifespan is short. Therefore, the filter elements have to be replaced frequently, which is undesirable from an environmental and economic standpoint.

[0005] Similar problems occurred when oil mist-containing air was passed through a filter element to capture the oil mist, and also when dust-containing air was passed through a filter element to capture the dust.

[0006] Japanese Patent Publication No. 2020-124653

[0007] This invention was made under such circumstances, and aims to provide a filter material and filter element with a long lifespan that can capture a large amount of unwanted materials such as mist and dust before a predetermined pressure loss occurs, because the pressure loss does not rise rapidly.

[0008] Accordingly, the present invention provides: [1] a three-dimensional mesh structure made of linear bodies with an average diameter of 100 μm or more, having raised portions where the linear bodies are mountain-shaped and recessed portions where the linear bodies are valley-shaped, and a bulk density of 25 kg / m³ ３ A filter material having the following nonwoven fabric, characterized in that the height of the raised portion is 6 mm or more: [2] The filter material according to [1], characterized in that the raised portions are scattered; [3] The filter material according to [2], characterized in that the raised portions are scattered in a staggered pattern; [4] The bulk density of the three-dimensional mesh structure is 50 kg / m ３ The present invention relates to a filter material according to any one of [1] to [3], characterized in that: [5] the nonwoven fabric has a thickness of 8 mm or more, characterized in that: [6] the nonwoven fabric has an average fiber diameter of 20 μm or more, characterized in that: [7] the filter material (second filter material) is made up of linear bodies with an average diameter of 100 μm or more, and comprises a three-dimensional mesh structure having raised portions where the linear bodies are mountain-shaped and recessed portions where the linear bodies are valley-shaped, and a nonwoven fabric with a thickness of 8 mm or more, characterized in that the height of the raised portions is 6 mm or more; [8] the filter material according to any one of [1] to [7] is mounted on a frame in a folded state, characterized in that: [9] the filter material according to any one of [1] to [7] is mounted on a frame in a folded state, characterized in that:

[10] the filter element according to [9] is mounted on a frame in a folded state.

[0009] The first filter material of the present invention is made up of linear bodies with an average diameter of 100 μm or more, and has a three-dimensional mesh structure having raised sections with a height of 6 mm or more where the linear bodies are mountain-shaped, and recessed sections where the linear bodies are valley-shaped. Because this three-dimensional mesh structure has a large surface area due to the presence of raised sections, it is less prone to rapid coating of unwanted materials or clogging with dust, allowing for a large collection capacity and a long filtration life. In addition, it has a bulk density of 25 kg / m³. ３ The presence of the following nonwoven fabrics allows for a higher collection rate and a longer filtration life.

[0010] Because the aforementioned raised sections are scattered, the side walls of the raised sections have many surfaces and a large surface area, which makes it less likely for a rapid buildup of unwanted materials or clogging with dust to occur, allowing for a larger collection capacity and a longer filtration life.

[0011] Because the raised sections are scattered in a staggered pattern, the distance between adjacent raised sections remains constant, making it less likely for unwanted material to accumulate and clog between adjacent raised sections. This reduces the likelihood of rapid accumulation of unwanted material and dust clogging, allowing for a larger collection capacity and a longer filtration life.

[0012] The bulk density of the three-dimensional mesh structure is 50 kg / m³. ３ The following features make it less likely for a rapid buildup of unwanted materials or clogging of dust to occur, allowing for a larger collection capacity and a longer filtration life.

[0013] Because the nonwoven fabric is 8 mm or thicker, it can capture a larger amount of unwanted material inside the fabric, resulting in a longer filtration life.

[0014] Because the average fiber diameter of the nonwoven fabric is 20 μm or more, the voids within the nonwoven fabric are relatively large, making it easier to capture unwanted materials within the nonwoven fabric. This results in a larger amount of collected unwanted materials and a longer filtration life.

[0015] The second filter medium of the present invention is composed of linear bodies with an average diameter of 100 μm or more, and includes a three-dimensional network structure having raised portions with a height of 6 mm or more where the linear bodies form mountain shapes and sunken portions where the linear bodies form valley shapes. Due to the presence of the raised portions, this three-dimensional network structure has a large area, so it is difficult for a rapid coating of unwanted substances or clogging of dust to occur, the collection amount can be increased, and the filtration life is long. Also, by having a non-woven fabric with a thickness of 8 mm or more, the amount of unwanted substances collected inside the non-woven fabric increases, so the filtration life is long.

[0016] The filter element of the present invention has the first or second filter medium in a pleated state and is attached to a frame body. By having the first or second filter medium in a pleated state, in addition to the large area of the filter medium, when a fluid containing unwanted substances is supplied to the filter element, the unwanted substances are first collected on the side wall surface on the inflow side in the raised portion, but it is difficult for unwanted substances to be collected on the side wall surface on the outflow side in the raised portion, and the flow of the fluid through the side wall surface on the outflow side in this raised portion is maintained. Therefore, it is difficult for a rapid coating of unwanted substances or clogging of dust to occur, the collection amount can be increased, and the filtration life is long.

[0017] Even if the filter element of the present invention is used for filtering a mist-containing gas, it is difficult for a mist coating to be formed rapidly, so the collection amount is large and the filtration life is long. In particular, even if it is used for filtering a gas containing paint mist, it is difficult for a paint coating to be formed rapidly, so the collection amount is large and the filtration life is long.

[0018] Schematic perspective view of the filter medium of the present invention Schematic perspective view of the three-dimensional network structure of the present invention (a) Outline view of line a-a in FIG. 2, (b) Outline view of line b-b in FIG. 2 Perspective view of the support that can be used when manufacturing the three-dimensional network structure of FIG. 2 Schematic perspective view with a part of the frame body of the filter element of the present invention removed Schematic top view with the upper plate of the filter element of FIG. 5 removed Schematic enlarged view of part C in FIG. 6 Schematic perspective view of another filter element of the present invention Schematic conceptual diagram of the mass method collection efficiency measuring device

[0019] Hereinafter, preferred embodiments of the filter medium of the present invention and a filter element using the same will be described.

[0020] (First Filter Medium) The first filter medium of the present invention is composed of linear bodies with an average diameter of 100 μm or more, and has a three-dimensional network structure having ridges where the linear bodies form mountain shapes and depressions where the linear bodies form valley shapes, and a bulk density of 25 kg / m ３ and the following non-woven fabric. The former network structure acts as a pre-filter for unwanted substances, and the latter non-woven fabric can collect unwanted substances that could not be collected by the network structure, so the collection efficiency is excellent.

[0021] (Three-dimensional Network Structure) The three-dimensional network structure constituting the first filter medium is composed of linear bodies with an average diameter of 100 μm or more and has a relatively coarse structure. Therefore, it is difficult for films of unwanted substances such as mist and clogging of dust to occur, the collection amount can be increased, and the filtration life is long. The larger the average diameter of the linear body, the coarser the structure of the three-dimensional network structure tends to be. Therefore, it is preferably 150 μm or more, more preferably 200 μm or more, still more preferably 250 μm or more, still more preferably 300 μm or more, still more preferably 350 μm or more, still more preferably 400 μm or more, and still more preferably 450 μm or more. On the other hand, if the average diameter of the linear body is too large, the collection property of unwanted substances such as mist will be significantly reduced, the load on the non-woven fabric described later will increase, the collection amount will decrease, and the filtration life will tend to be shortened. Therefore, it is preferably 1000 μm or less, more preferably 850 μm or less, and still more preferably 700 μm or less.

[0022] The diameter of this linear body refers to the average value of 200 points randomly selected and measured using an outside micrometer (measurement range: 0 to 25 mm) defined in 3.1 of JIS B 7502 (2016) "Micrometer".

[0023] Note that this linear body is a fiber-like one that extends in a curved and / or linear shape. Therefore, the three-dimensional network structure composed of linear bodies has a large number of voids, and unwanted substances such as mist can be collected. In particular, when the linear body is curved, it can be in a state of being entangled and / or fused with a large number of linear bodies, and it is suitable because it has excellent shape retention of the ridges.

[0024] As shown in Figure 1, a schematic perspective view of the three-dimensional mesh structure of the present invention, which consists of a three-dimensional mesh structure 1 and a nonwoven fabric 2, the three-dimensional mesh structure 1 has repeating continuously extending raised portions 11 in the shape of mountains and continuously extending recessed portions 12 in the shape of valleys, and the height H of the raised portions is 6 mm or more. In this way, because it has raised portions and recessed portions of linear bodies, the area that can participate in filtration is large, so rapid film formation of unwanted materials and clogging of dust are less likely to occur, the amount of material collected can be increased and the filtration life is extended.

[0025] Although the three-dimensional mesh structure in Figure 1 does not have linear bodies on the back side of the raised portion, linear bodies may also be present on the back side of the raised portion. The presence of linear bodies on the back side of the raised portion allows these linear bodies to participate in the collection of unwanted substances such as mist.

[0026] Furthermore, although the three-dimensional mesh structure in Figure 1 has regularly repeating raised portions 11 and recessed portions 12, it is not necessary for them to be regularly repeating or to be repeated. However, having regularly repeating raised portions 11 and recessed portions 12 is a preferred configuration because it provides a large surface area, uniform collection performance, and stable collection.

[0027] Furthermore, although the raised sections of the three-dimensional mesh structure in Figure 1 are all the same height, this is not necessary. However, having the raised sections all the same height is preferable because it ensures uniform and stable collection performance.

[0028] Furthermore, unlike Figure 1, the three-dimensional mesh structure of the present invention preferably has scattered raised portions 11, as shown in the schematic perspective view of the three-dimensional mesh structure in Figure 2. This is because the scattered raised portions 11 have a large number of side wall surfaces, which allows for a larger area to participate in collection, making it less likely for a rapid film of unwanted materials or clogging with dust to occur, thus increasing the amount of collected material and extending the filtration life. When the raised portions 11 are scattered in this way, there are inevitably scattered depressions 12 formed by linear bodies in a valley-like shape between the raised portions 11.

[0029] In Figure 2, the state of the raised portions 11 and recessed portions 12 is difficult to see, so schematic outlines of the three-dimensional mesh structure in Figure 2 along line a-a and line b-b are shown in Figures 3(a) and (b), respectively. As shown in the schematic outline of the three-dimensional mesh structure along line a-a in Figure 3(a), it has two raised portions 11 and three recessed portions 12, whereas on the near side of the drawing in Figure 2, as shown in the schematic outline along line b-b, it has three raised portions 11 and two recessed portions 12. Thus, in the drawing of the three-dimensional mesh structure in Figure 2, mountain-like raised portions are regularly scattered in a staggered pattern in both the left-right and front-back directions. In this way, because the raised areas are scattered in a staggered pattern, the distance between adjacent raised areas is constant, making it less likely for unwanted materials to accumulate and clog the gaps between them. As a result, rapid accumulation of unwanted materials and dust clogging are less likely to occur, allowing for a larger collection capacity and a longer filtration life.

[0030] However, the raised portions 11 do not need to be scattered in a staggered pattern; they may be scattered in a gingham check pattern, where the schematic outline of the three-dimensional mesh structure along line a-a and the schematic outline along line b-b are the same as shown in Figure 3(a).

[0031] Furthermore, as shown in Figure 2, even when the raised portions 11 are scattered, linear bodies may be present on the back side of the raised portions. The presence of linear bodies on the back side of the raised portions allows these linear bodies to participate in the collection of unwanted substances such as mist.

[0032] Furthermore, although the raised portions 11 in the three-dimensional mesh structure in Figure 2 are regularly spaced, they do not necessarily need to be regularly spaced. However, the regularly spaced raised portions 11 are preferable because they provide a large surface area, uniform collection performance, and stable collection.

[0033] Furthermore, although the three-dimensional mesh structure in Figure 2 has the same shape and size of the raised portions 11, it is not necessary for them to be the same shape and / or size. However, having raised portions 11 of the same shape and size scattered throughout is preferable because it allows for uniform and stable collection performance.

[0034] The three-dimensional mesh structure of the present invention has raised portions, the height of which is 6 mm or more. A height of 6 mm or more ensures a sufficiently large surface area, making it less likely for rapid film formation of unwanted materials or clogging with dust to occur, thus increasing the amount of collected material and extending the filtration life. The higher the height, the less likely rapid film formation of unwanted materials or clogging with dust to occur, therefore a height of 8 mm or more is preferable, 10 mm or more is more preferable, and 12 mm or more is even preferable. On the other hand, to further increase the filtration area, it is preferable to use the filter material in a folded state. However, if the height of the raised portions is too high, the raised portions are more likely to come into contact with each other, resulting in increased likelihood of film formation of unwanted materials or clogging with dust between the contacting raised portions, which may prevent the desired amount of collected material, i.e., a long filtration life. Therefore, the height of the raised portions is preferably 28 mm or less, more preferably 25 mm or less, and even more preferably 22 mm or less.

[0035] In this invention, "height of the raised portion" refers to the distance from the bottom to the top of the raised portion of the three-dimensional mesh structure, for example, H in Figure 1 and H in Figure 3(a). Note that the linear bodies may be fuzzy or the height of the raised portions may differ, therefore, 1 g / cm² is applied to the surface of the raised portion of the three-dimensional mesh structure. ２ The top of the raised section under compressive load is used as the reference point.

[0036] Furthermore, when the three-dimensional mesh structure of the present invention has scattered raised portions, its shape is not particularly limited, but for example, it can be hemispherical, conical, frustoconical, pyramidal (e.g., triangular pyramidal), pyramidal (e.g., triangular frustoconical), cylindrical, or prism-shaped (e.g., triangular prism).

[0037] The three-dimensional mesh structure of the present invention has raised portions, but it is preferable that the linear bodies are intertwined and / or fused together in order to maintain its shape and have excellent collection performance when collecting unwanted materials. In particular, it is a preferred embodiment if the recessed portions have fused masses in which the linear bodies are fused together, as this provides excellent reinforcement to the raised portions.

[0038] Further, the back surface of the surface where the raised portions of the three-dimensional network structure exist may have sunken portions corresponding to the raised portions, and may also have raised portions corresponding to the sunken portions, or may be a smooth surface without any sunken or raised portions. When it is a smooth surface as in the latter case, a linear body exists in the space corresponding to the raised portion. In addition to being able to reinforce the raised portion, since the linear body can contribute to the collection of unwanted substances, it is a preferred embodiment.

[0039] The linear body constituting the three-dimensional network structure is preferably composed of a thermoplastic resin that can be fused. For example, it is preferably composed of polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins such as nylon 6 and nylon 66, polyolefin resins such as polypropylene and polyethylene, etc. In addition, the resin constituting the linear body may preferably be selected according to the type of unwanted substances and the place of use. For example, when the mist is aqueous, such as the mist of an aqueous paint, it is preferably composed of a polyamide resin with excellent hydrophilicity. When the mist is oily, such as an oil mist, it is preferably composed of a polyolefin resin with excellent lipophilicity. When used in a place where the temperature is high and heat resistance is required, it is preferably composed of a polyester resin.

[0040] The bulk density of the three-dimensional network structure of the present invention is preferably 50 kg / m ３ or less. With such a bulk density, the voids are large and numerous, so it is difficult for sudden coating of unwanted substances or clogging of dust to occur, the collection amount can be increased, and the filtration life is long. A more preferable bulk density is 40 kg / m ３ or less, and a still more preferable bulk density is 30 kg / m ３ or less, and a still more preferable bulk density is 25 kg / m ３ or less. On the other hand, if the bulk density of the three-dimensional network structure is too low, the collection efficiency of unwanted substances tends to deteriorate, so it is preferably 10 kg / m ３ or more, and more preferably 15 kg / m ３ or more.

[0041] This bulk density (D) is per unit area (1 m ２D is a value calculated from the following formula, based on the mass (M, in kg) and thickness (T), i.e., the height of the raised part (in m): D = M / T

[0042] Note that the unit area of ​​a three-dimensional mesh structure is defined as the area enclosed by the outer perimeter of the projection drawing of the three-dimensional mesh structure, which is 1 m². ２ This means that the area of ​​the outer perimeter of the projection is 1 m². ２ If it is less than 1m ２ This refers to the value converted to [a specific currency].

[0043] The unit area (1 m²) of the three-dimensional mesh structure of the present invention ２ The mass per unit is not particularly limited, but it is preferably the mass that results in the bulk density. For example, it can be 0.10 to 0.50 kg, 0.20 to 0.40 kg, or 0.25 to 0.35 kg.

[0044] A three-dimensional mesh structure with scattered raised portions as described in the present invention can be manufactured, for example, by melting a resin, extruding it from a nozzle, and accumulating the extruded linear body on a support having partially protrusions. More specifically, as shown in the perspective view in Figure 4, a three-dimensional mesh structure can be manufactured by accumulating a linear body, which is molten resin extruded from a nozzle, along the surface of the protrusions 21 of the support 20 on a support 20 having a large number of staggered protrusions 21, thereby creating a structure with raised portions corresponding to the spaces between the protrusions 21 and recessed portions corresponding to the protrusions 21. When a support such as that in Figure 4 is used, a three-dimensional mesh structure with raised portions and recessed portions scattered in a staggered pattern can be manufactured. Alternatively, a three-dimensional mesh structure with raised portions can be manufactured by melting a resin, extruding it from a nozzle, accumulating the extruded linear body on a support to form a sheet, and then heating and pressurizing it with a heating roller or the like that having protrusions. In particular, the former method of accumulating linear bodies, which are molten resin extruded from a nozzle, onto a support having protrusions is a more preferable manufacturing method because the linear bodies do not form a film, thus not impairing the permeability of the processing fluid; there are no compressed parts of the linear bodies, the state of the linear bodies is uniform throughout the entire three-dimensional network structure, resulting in uniform filtration performance; and moreover, the linear bodies can be filled on the back side of the raised parts.

[0045] Furthermore, after accumulating the linear molten resin extruded from the nozzle onto a support having protrusions, a heating roller or the like is applied to the support to fuse only the linear material present on the protrusions, thereby improving the morphological stability of the three-dimensional mesh structure. In the three-dimensional mesh structure manufactured in this way, the linear material is fused only in the recessed areas corresponding to the protrusions of the support, forming a resin mass.

[0046] (Nonwoven fabric) The first filter material of the present invention, in addition to the three-dimensional mesh structure described above, has a nonwoven fabric (for example, a flat nonwoven fabric), which allows it to capture unwanted materials that could not be captured by the three-dimensional mesh structure, thus providing a minimum level of filtration performance. Furthermore, the bulk density of the nonwoven fabric is 25 kg / m³. ３ The following conditions allow for a higher collection rate and longer filtration life: The bulk density of the nonwoven fabric is 25 kg / m². ３The following conditions indicate that the nonwoven fabric has a relatively coarse structure, meaning that unwanted materials can be captured even in the internal voids of the nonwoven fabric. A more preferable bulk density is 20 kg / m³. ３ The following are the values, and a more preferable bulk density is 15 kg / m³. ３ The following are the values, and a more preferable bulk density is 12 kg / m³. ３ The following applies. On the other hand, if the bulk density of the nonwoven fabric is too low, the ability to collect unwanted materials tends to decrease, so 3 kg / m ３ Preferably, it is 5 kg / m ３ It is more preferable to have a load of 7 kg / m² or more. ３ It is even more preferable if the above conditions are met.

[0047] This bulk density (D) is a value obtained in the same way as the bulk density of a three-dimensional mesh structure. In other words, the bulk density of the nonwoven fabric per unit area (1 m²) ２ D is a value calculated from the following formula, based on the mass (M, in kg) and thickness (T) per unit area: D = M / T

[0048] Note that the unit area of ​​nonwoven fabric is defined as the area enclosed by the outer perimeter of the projection drawing of the nonwoven fabric, which is 1 m². ２ This means that the area of ​​the outer perimeter of the projection is 1 m². ２ If it is less than 1m ２ This refers to the value converted to [a certain value]. Also, the thickness is 1 g / cm² for nonwoven fabric. ２ This refers to the thickness when a load is applied.

[0049] The nonwoven fabric of the present invention has a thickness and bulk density of 25 kg / m². ３ While not particularly limited as long as it falls within the following limits, a thickness of 8 mm or more is preferable because it increases the amount of unwanted material collected in the internal voids of the nonwoven fabric, thereby extending the filtration life. A more preferable thickness is 10 mm or more, an even more preferable thickness is 12 mm or more, and an even more preferable thickness is 15 mm or more. On the other hand, if the thickness becomes too thick, the structure of the nonwoven fabric tends to become too coarse, resulting in poor collection of unwanted material. Therefore, a thickness of 33 mm or less is preferable, 29 mm or less is preferable, and 25 mm or less is even preferable.

[0050] Furthermore, the unit area of ​​the nonwoven fabric of the present invention (1 m²) ２The basis weight, which is the mass per unit area, is calculated based on a bulk density of 25 kg / m³. ３ As long as it is within the following limits, it is not particularly limited to 80-270 g / m². ２ It can be 115-235 g / m² ２ Preferably, it is 150-200 g / m ２ It would be even more preferable if that were the case.

[0051] The nonwoven fabric of the present invention can be composed of thermoplastic resin fibers, and may include fibers composed of one or more types of resins, such as polyester resins like polyethylene terephthalate and polybutylene terephthalate, polyamide resins like nylon 6 and nylon 66, and polyolefin resins like polypropylene and polyethylene.

[0052] For example, if a nonwoven fabric contains fibers made of two types of resin, and there is a difference in melting points between the two resins, and the lower melting point resin is exposed on the fiber surface in the fused fibers (e.g., core-sheath fused fibers, side-by-side fused fibers, sea-island fused fibers, etc.), then the fusion can be achieved by the lower melting point resin, while the fiber shape can be maintained by the higher melting point resin, resulting in a nonwoven fabric with excellent strength and dimensional stability. Examples of combinations of two resins with such a difference in melting points include copolymerized polyester / polyester, copolymerized polypropylene / polypropylene, polypropylene / polyamide, polyethylene / polypropylene, polypropylene / polyester, and polyethylene / polyester. If it is preferable for the nonwoven fabric to be electrically charged to have excellent waste collection performance, then it is preferable to include fibers containing polyolefin resin on the fiber surface.

[0053] The nonwoven fabric of the present invention preferably has an average fiber diameter of 20 μm or more. An average fiber diameter of 20 μm or more means that the structure of the nonwoven fabric is relatively coarse, and unwanted materials can be collected even in the internal voids of the nonwoven fabric. A more preferable average fiber diameter is 25 μm or more, an even more preferable average fiber diameter is 30 μm or more, and an even more preferable average fiber diameter is 40 μm or more. On the other hand, if the average fiber diameter is too large, the structure of the nonwoven fabric tends to be too coarse, resulting in poor collection of unwanted materials. Therefore, the average fiber diameter is preferably 80 μm or less, more preferably 70 μm or less, and even more preferably 60 μm or less.

[0054] The average fiber diameter of a nonwoven fabric refers to the arithmetic mean of the fiber diameters at 200 constituent fibers. This fiber diameter can be measured, for example, from an electron microscope image of the nonwoven fabric. If the cross-sectional shape of the fiber is circular, it represents the diameter of that circle; if the cross-sectional shape of the fiber is non-circular, it represents the diameter of a circle with the same area as the cross-sectional area.

[0055] Furthermore, while there are no particular limitations on the fiber length of the nonwoven fabric constituent fibers, it is preferably 20 to 160 mm, more preferably 45 to 135 mm, and even more preferably 70 to 110 mm, in order to facilitate intertwining of the fibers and to ensure excellent shape stability of the nonwoven fabric.

[0056] Furthermore, the fiber cross-sectional shape may be circular, triangular, alphabet-shaped, irregular, or otherwise non-circular.

[0057] The nonwoven fabric of the present invention can be composed of two or more types of fibers that differ in terms of resin composition, resin arrangement, fiber diameter, fiber length, and / or fiber cross-sectional shape.

[0058] The nonwoven fabric of the present invention has a bulk density of 25 kg / m². ３ As long as the following conditions are met, the material may be manufactured by any method, such as the dry method, wet method, spunbond method, meltblown method, electrospinning method, or flash spinning method. Among these, the dry method yields a bulk density of 25 kg / m³. ３It is preferable because it is easy to form a nonwoven fabric that meets the following criteria, and it is also easy to construct it with fibers having the preferred fiber diameter and / or fiber length as described above.

[0059] Furthermore, nonwoven fabrics produced by a preferred dry method can be manufactured, for example, by opening the fibers using a carding machine or air array device to form a fiber web, followed by bonding with a liquid binder, entanglement with needles or water flow, and / or fusion of fused fibers constituting the fiber web. Among these, nonwoven fabrics bonded by bonding with a liquid binder or fusion of fused fibers, which can bond the fibers while maintaining the thickness of the fiber web, are preferred, and nonwoven fabrics bonded by fusion of fused fibers, which do not have a coating formed and better retain the voids between fibers, are even more preferred.

[0060] (First filter material structure) The first filter material of the present invention has a three-dimensional mesh structure and a nonwoven fabric as described above, but other materials may be provided for purposes such as reinforcement, as long as they do not impair the functions of these materials. For example, a nonwoven fabric different from the nonwoven fabric, a woven fabric, a knitted fabric, a net, etc. may be provided. In addition, a sheet equipped with a harmful gas removal material may be provided for the purpose of removing harmful gases.

[0061] Furthermore, in the first filter material of the present invention, the three-dimensional mesh structure and the nonwoven fabric may be bonded together as a single unit by a hot melt adhesive, emulsion adhesive, fusion of the linear parts of the three-dimensional mesh structure and / or the constituent fibers of the nonwoven fabric, so as not to peel off, or the three-dimensional mesh structure and the nonwoven fabric may be simply laminated and separable. As described later, the first filter material of the present invention is preferably used in a folded state, but even if a shift occurs between the three-dimensional mesh structure and the nonwoven fabric when it changes from a flat state to a folded state, the three-dimensional mesh structure and the nonwoven fabric can remain in a folded state without causing distortion between them, and are therefore preferred because they have excellent filtering performance for unwanted materials. Furthermore, the presence of a third component in hot-melt adhesives or emulsion adhesives, or structural changes due to the fusion of linear bodies and / or nonwoven fabric constituent fibers in a three-dimensional network structure, may impair the desired performance. However, simply being in a laminated state also has the advantage of making it easier to achieve the desired performance.

[0062] (Second filter material) The first filter material of the present invention consists of linear bodies with an average diameter of 100 μm or more, and comprises a three-dimensional mesh structure having mountain-shaped raised portions and valley-shaped recessed portions, and a nonwoven fabric with a thickness of 8 mm or more. The former mesh structure acts as a pre-filter for unwanted materials, and the latter nonwoven fabric can capture unwanted materials that could not be captured by the mesh structure, thus providing excellent collection efficiency.

[0063] (Three-dimensional mesh structure) The three-dimensional mesh structure constituting the second filter material can be exactly the same as the three-dimensional mesh structure constituting the first filter material.

[0064] (Nonwoven Fabric) The second filter material of the present invention, in addition to a three-dimensional mesh structure, has a nonwoven fabric (for example, a flat nonwoven fabric), which allows it to capture unwanted materials that could not be captured by the three-dimensional mesh structure, thus providing minimum filtration performance. Furthermore, the thickness of the nonwoven fabric is 8 mm or more, which increases the amount of unwanted materials that can be captured and extends the filtration life. In other words, because the nonwoven fabric is thick at 8 mm or more, a large amount of unwanted materials can be captured inside the nonwoven fabric, resulting in a long filtration life. A preferred thickness is 10 mm or more, a more preferred thickness is 12 mm or more, and an even more preferred thickness is 15 mm or more. On the other hand, if the thickness becomes too thick, the structure of the nonwoven fabric tends to become too coarse, which tends to worsen the ability to capture unwanted materials. Therefore, a thickness of 33 mm or less is preferred, 29 mm or less is more preferred, and 25 mm or less is even more preferred. The thickness is the same as the first filter material, 1 g / cm of nonwoven fabric. ２ This refers to the thickness when a load is applied.

[0065] Furthermore, the bulk density of the nonwoven fabric is 25 kg / m². ３ Preferably, the bulk density is 25 kg / m³. ３ The reason for this is that the nonwoven fabric has a relatively coarse structure, making it easier to capture unwanted materials in the internal voids of the nonwoven fabric. A more preferable bulk density is 20 kg / m³. ３ The following are the values, and a more preferable bulk density is 15 kg / m³. ３ The following are the values, and a more preferable bulk density is 12 kg / m³. ３ The following applies. On the other hand, if the bulk density of the nonwoven fabric is too low, the ability to collect unwanted materials tends to decrease, so 3 kg / m ３ Preferably, it is 5 kg / m ３ It is more preferable to have a load of 7 kg / m² or more. ３ It is even more preferable that the above conditions are met. This bulk density (D) is a value that is calculated in the same way as the nonwoven fabric constituting the first filter material.

[0066] Furthermore, the unit area of ​​nonwoven fabric (1 m ２ The basis weight, which is the mass per unit area, is not particularly limited, but as long as the thickness is 8 mm or more, the bulk density is preferably 25 kg / m³. ３ As follows, 80-270 g / m ２It can be 115-235 g / m² ２ Preferably, it is 150-200 g / m ２ It is preferable that this is the case.

[0067] Furthermore, the constituent fibers (resin composition, resin arrangement, fiber diameter, fiber length, fiber cross-sectional shape, etc.) and manufacturing method of the nonwoven fabric constituting the second filter material can be the same as those of the nonwoven fabric constituting the first filter material.

[0068] (Second filter material structure) The second filter material of the present invention, like the first filter material, may include materials other than a three-dimensional mesh structure and nonwoven fabric.

[0069] Furthermore, the three-dimensional mesh structure and the nonwoven fabric may be bonded together as a single unit, or they may simply be stacked and separable; however, similar to the first filter material, it is preferable that they be simply stacked.

[0070] (Filter Element) The filter element of the present invention has a first filter material or a second filter material (hereinafter collectively referred to as "filter material") as described above, which is mounted on a frame in a folded state. Because the filter material of the present invention is in a folded state, in addition to having a large filtration area, when a fluid containing unwanted substances is supplied to the filter element, the unwanted substances are first collected on the inlet side wall surface of the raised section, but unwanted substances are less likely to be collected on the outlet side wall surface of the raised section. As a result, the flow of fluid through the outlet side wall surface of the raised section is maintained, and a sudden increase in pressure loss due to a film of unwanted substances or clogging with dust is less likely to occur, thus increasing the amount of collected substances and extending the filtration life.

[0071] This point will be explained with reference to Figures 5 to 7. Figure 5 is a schematic perspective view with a portion of the frame of the filter element removed, Figure 6 is a schematic top view with the top plate of the filter element in Figure 5 removed, and Figure 7 is a schematic enlarged view of section C in Figure 6. In Figures 6 and 7, the filter material is provided with a three-dimensional mesh structure having a repeating, continuously extending raised portion 11 as shown in Figure 1.

[0072] As shown in Figure 5, the filter element 200 of the present invention houses the aforementioned filter material 100 in a folded state inside a frame consisting of a right side wall plate 210R, a left side wall plate 210L, a bottom plate 210B, and an upper plate (not shown). When a fluid S containing unwanted substances is supplied to such a filter element 200, as shown in Figure 7, unwanted substances are collected at the inlet side wall surface 11a of the raised portion 11, but unwanted substances are less likely to be collected at the outlet side wall surface 11b of the raised portion 11. The flow of fluid through the outlet side wall surface 11b of the raised portion 11 is maintained, and a sudden increase in pressure loss due to a film of unwanted substances or clogging with dust is less likely to occur, thus increasing the amount of collected substances and extending the filtration life.

[0073] Furthermore, when using a filter material having a three-dimensional mesh structure with raised sections scattered in a staggered pattern, as shown in Figure 2, in addition to the wide filtration area due to the scattered raised sections, a supply channel (corresponding to the scattered depressions) for the fluid S containing unwanted materials is secured. In other words, even if the collection of unwanted coatings and dust progresses on the inflow side wall of the raised sections, the fluid can flow through the scattered depressions, thus preventing a sudden increase in pressure loss, allowing for a larger collection volume and a longer filtration life. Moreover, since raised sections are present downstream of the fluid that has flowed through the scattered depressions, the collection efficiency is also excellent.

[0074] The filter element of the present invention is in a pleated state, but this state is not particularly limited as it varies depending on the type of fluid containing unwanted substances. For example, in the case of collecting paint mist from a gas, which is a particularly suitable application, the height of the pleats is preferably 280 to 490 mm, more preferably 320 to 450 mm, and even more preferably 360 to 410 mm. With such pleat heights, adjacent pleats do not come into contact, a wide filtration area can be maintained, and the amount of collected material tends to increase.

[0075] Furthermore, the pitch (P in Figure 6), which is the spacing between the folds, is not particularly limited, but for example, in the case of collecting paint mist from a gas, which is a particularly suitable application, it is preferably 122 to 300 mm, more preferably 125 to 240 mm, and even more preferably 130 to 210 mm. With such a fold pitch, adjacent folds do not come into contact, a wide filtration area can be maintained, and the amount of collected material tends to increase.

[0076] Furthermore, the fold angle (θ in Figure 6) is not particularly limited, but for example, in the case of collecting paint mist from a gas, which is a particularly suitable application, it is preferably 18.5 to 45°, more preferably 19 to 35°, and even more preferably 20 to 31°. With such a fold angle, adjacent folds do not come into contact, a wide filtration area can be maintained, and both collection efficiency and collection amount tend to be high.

[0077] Furthermore, the number of folds varies depending on the size of the intended use, etc., and is not particularly limited.

[0078] Such pleated state of filter material can be formed, for example, by methods using pleating machines such as reciprocating or rotary types, or by pressing with a zigzag-shaped mold.

[0079] In the filter element of the present invention, the filter material is in a folded state, and it is preferable that it is fixed by a frame so that this folded state can be maintained during use. The frame is preferably made of a rigid material so as to maintain the folded state of the filter material, and can be, for example, wood, metal plate, plastic plate, or corrugated cardboard. If the filter is to be incinerated and disposed of after several washes and regenerations, a frame made of wood is preferable, and if it is difficult to wash and regenerate and is to be incinerated and disposed of after a single use, a frame made of corrugated cardboard is preferable.

[0080] The method of fixing the filter material with the frame is not particularly limited, but examples include fusing the frame and / or the filter material components together, bonding the frame and filter material via liquid adhesive, hot melt adhesive, or adhesive sheet, or fixing it by physical means such as using a frame with notches and attaching the filter material to these notches. However, the filter material does not need to be actively fixed to the frame, and the folded state of the filter material may be maintained as a result of the filter material being housed within the frame.

[0081] In the filter element of the present invention, the filter material is mounted on the frame in a folded state. However, to more actively maintain the folded state of the filter material, it is preferable that the outer surface of the folded filter material is shaped by a shape-retaining member. For example, if a pair of shape-retaining members are attached to both outer surfaces of the folded filter material that intersect with the direction of the fold lines, the retention of the folded state of the filter material is excellent. In addition to these two outer surfaces, shape-retaining members may also be attached to both outer surfaces parallel to the direction of the fold lines.

[0082] Such shape-retaining members can be, for example, sheet-like materials such as wood, metal plates, plastic plates, woven or knitted fabrics, nonwoven fabrics, foamed sheets, paper, corrugated cardboard, or composites thereof. Attaching the shape-retaining member to the folded filter material can be done by, for example, fusing the shape-retaining member and / or the filter material components, bonding the shape-retaining member and the filter material via a liquid adhesive, hot-melt adhesive, or adhesive sheet, or by physical means such as using a shape-retaining member with notches and attaching the filter material to these notches. The shape-retaining member can also be a foam formed by applying a foaming resin and then foaming it.

[0083] Furthermore, in addition to the pair of shape-retaining members attached to both outer surfaces of the folded filter material that intersect with the direction of the folds, or alternatively, one or more separators may be provided between the outer surfaces that intersect with the direction of the folds, extending in a direction intersect with the direction of the folds of the folded filter material, for example, parallel to the outer surfaces. By having such separators, contact between adjacent filter materials can be prevented, resulting in a filter element with excellent collection performance, a large collection capacity, and a long lifespan.

[0084] Such separators, like shape-retaining members, can be made from materials such as wood, metal plates, plastic plates, woven or knitted fabrics, nonwoven fabrics, foamed sheets, paper, corrugated cardboard, linear resins, or composites thereof.

[0085] Furthermore, the separator may have a shape and size that perfectly matches the valleys of the folds in the filter media, or it may have a shape and size that only partially matches the valleys of the folds in the filter media.

[0086] Furthermore, the separator can be located on the inlet side, outlet side, or both sides of the fluid containing unwanted materials.

[0087] Furthermore, the separators may be continuous, spanning the peaks of the folds in the filter material, or they may not span the peaks of the folds, with multiple separators in each individual valley.

[0088] In Figure 5, the filter element is shown with the entire filter material fitted inside the frame, but it is not necessary for the entire filter material to be fitted inside the frame. For example, as shown in Figure 8, a schematic perspective view of another filter element, the filter material 100 may be fitted with the frame 210 only at the end on the side where the fluid containing unwanted materials flows in, and the filter material 100 may be fixed by the frame 210.

[0089] The filter element of the present invention is less prone to rapid formation of unwanted film or clogging with dust, allowing for a large collection capacity and a long filtration life while still providing minimum filtration performance. For example, it can be used to remove dust and mist from gases containing dust or mist. In particular, mist (especially paint mist) tends to form a film upon collection, leading to a rapid increase in pressure loss, resulting in a small collection capacity and a short filtration life. However, even when collecting mist (especially paint mist), the filter element of the present invention is less prone to film formation and a rapid increase in pressure loss compared to conventional filters. Therefore, it not only offers superior collection performance but also a large collection capacity and a long filtration life.

[0090] For example, the filter element of the present invention can have a mass collection efficiency of 85% or more, preferably 90% or more, as measured by the following method. Furthermore, the paint supply amount, as measured by the following method, can be 12,000 g or more, preferably 13,000 g or more, more preferably 14,000 g or more, and even more preferably 15,000 g or more.

[0091] (Method for measuring collection efficiency by mass method) 1. Fold the filter material into pleats with a pleat height of 385 mm, 4 pleats, a pitch of 151 mm, and a pleat angle of 22.6°, and place it in a frame measuring 610 mm in width, 610 mm in height, and 500 mm in depth to prepare a test filter element.

[0092] 2. Prepare the paint mixture as follows: (1) 10 parts of Kansai Paint Co., Ltd.'s two-component acrylic urethane resin topcoat paint (Retan PG80) (2) 1 part of Kansai Paint Co., Ltd.'s Retan PG80 hardener (3) 10 parts of Kansai Paint Co., Ltd.'s Kanpe industrial urethane thinner

[0093] 3. As the final filter element, it retains at least 98% of the sprayed paint and conforms to JIS B 9908 (2019) J-ePM １ Prepare a bag filter with at least 95% efficiency. Also, measure the mass of the bag filter.

[0094] 4. As specified in ASHRAE 52.1-1992, the test filter element 200 and the final filter element 300 are installed in order from the upstream side (see Figure 9).

[0095] The paint prepared in 5.2 is sprayed upstream of the test filter element 200 at a spray pressure of 0.2 MPa, and ventilation is provided at a wind speed of 1.0 m / sec. (see Figure 9, airflow 400). The amount of paint supplied (F) sprayed until the pressure loss of the test filter element 200 reaches 500 Pa is measured. The mass of the final filter element 300 when the pressure loss reaches 500 Pa is also measured.

[0096] 6. The amount of paint mist (L) that could not be captured by the test filter element is calculated from the difference in mass between the final filter element after the test and the final filter element before the test.

[0097] 7. The mass collection efficiency (Me) is calculated from the amount of paint sprayed (F) until the pressure loss reaches 500 Pa and the amount of paint mist (L) that could not be collected by the test filter element, using the following formula: Me = [(F - L) / F] × 100

[0098] Furthermore, the initial pressure loss during the measurement of the mass collection efficiency described above can be 100 Pa or less, preferably 90 Pa or less, more preferably 80 Pa or less, and even more preferably 70 Pa or less.

[0099] The filter material and filter element of the present invention will be described below based on examples, but these are merely preferred examples to facilitate understanding of the present invention, and the present invention is not limited to the contents of these examples.

[0100] (Preparation of three-dimensional mesh structures) Three-dimensional mesh structures 1 to 9 were prepared, each having a fluid inlet surface with curved linear bodies made of polyamide resin having an average diameter as shown in Table 1, and a fluid inlet surface with curved linear bodies arranged in a regular, staggered pattern, with raised sections of approximately the same height and shape in a square pyramidal shape and recessed sections of approximately the same depth and shape located between the raised sections, and a smooth fluid outlet surface made of curved linear bodies. In these three-dimensional mesh structures 1 to 9, the linear bodies were intertwined with each other and partially fused together, and in particular, fused masses were present in the recessed sections. Furthermore, linear bodies were also present in the space between the surface of the raised sections and the fluid outlet surface in three-dimensional mesh structures 1 to 9. ２ The mass per unit area, thickness (height of the raised portion), and bulk density are as shown in Table 1.

[0101]

[0102] (Preparation of nonwoven fabric) The following fibers were prepared: 1. Core-sheath fused fiber A: Core-sheath fused fiber A consisting of a polypropylene resin with a melting point of 160°C for the core component and a polyethylene resin with a melting point of 140°C for the sheath component (fineness: 6.6 dtex, fiber diameter: 30 μm, fiber length: 102 mm, fiber cross-sectional shape: circular).

[0103] 2. Core-sheath type fused fiber B: Core-sheath type fused fiber A (fineness: 20 dtex, fiber diameter: 52 μm, fiber length: 76 mm, fiber cross-sectional shape: circular) consists of a core component made of polypropylene resin with a melting point of 160°C and a sheath component made of polyethylene resin with a melting point of 140°C.

[0104] 3. Core-Sheath Type Fused Fiber C: Core-sheath type fused fiber C consists of a polypropylene resin core with a melting point of 160°C and a polyethylene resin sheath with a melting point of 140°C (fineness: 16 dtex, fiber diameter: 47 μm, fiber length: 76 mm, fiber cross-sectional shape: circular).

[0105] 4. Core-sheath type fused fiber D: The core component is made of polypropylene resin with a melting point of 160°C, and the sheath component is made of polyethylene resin with a melting point of 140°C. Core-sheath type fused fiber D (fineness: 47 dtex, fiber diameter: 80 μm, fiber length: 89 mm, fiber cross-sectional shape: circular).

[0106] 5. Core-sheath type fused fiber E: The core component is made of polypropylene resin with a melting point of 160°C, and the sheath component is made of polyethylene resin with a melting point of 140°C. Core-sheath type fused fiber E (fineness: 3.3 dtex, fiber diameter: 21 μm, fiber length: 51 mm, fiber cross-sectional shape: circular).

[0107] 6. Core-sheath fused fiber F: A core-sheath fused fiber F consisting of a polypropylene resin with a melting point of 160°C as the core component and a polyethylene resin with a melting point of 140°C as the sheath component (fineness: 1.7 dtex, fiber diameter: 15 μm, fiber length: 51 mm, fiber cross-sectional shape: circular).

[0108] Next, the fibers were used individually or in mixtures according to the formulations shown in Table 2, and a fiber web was formed using a carding machine.

[0109] Next, this fiber web was supplied to an air-through type dryer, and hot air at a temperature of 140°C was passed through it at a speed of 6 m / s to perform a fusion treatment with the sheath component of the core-sheath type fused fiber, thereby producing flat nonwoven fabrics a to k having the basis weight, thickness, and bulk density shown in Table 2.

[0110]

[0111] (Manufacturing of filter elements) (Examples 1-4, Comparative Examples 1-4) In the combinations shown in Table 3, a three-dimensional mesh structure and a nonwoven fabric were simply laminated to form a filter material. Then, the material was folded with a pleat height of 385 mm, 4 pleats, a pitch of 151 mm, and a pleat angle of 22.6°, and housed in a frame made of corrugated cardboard measuring 610 mm wide, 610 mm high, and 500 mm deep to manufacture the filter elements of Examples 1-4 and Comparative Examples 1, 2, and 4. The corrugated cardboard used had a fluid inlet and outlet measuring 530 mm wide and 530 mm high, and the three-dimensional mesh structure of the filter material was housed facing the fluid inlet side. In addition, to prevent adjacent filter surfaces of the filter material from contacting each other, three corrugated cardboard separators, each having a triangular shape and size corresponding to the valleys of the pleats, were placed on both the inlet and outlet sides, evenly spaced apart.

[0112] Comparative Example 3 uses a paper exhaust filter (manufactured by Otsuka Brush Manufacturing Co., Ltd., Maru-Te Craft Pad) as a filter material instead of a three-dimensional mesh structure.

[0113] Next, the mass collection efficiency and paint supply rate of each filter element were measured using the method described above. The results are shown in Table 3.

[0114]

[0115] A comparison between Comparative Example 1 and Example 3 shows that, in addition to the three-dimensional mesh structure, the bulk density is 25 kg / m³. ３ It was found that by using the following nonwoven fabrics, or nonwoven fabrics with a thickness of 8 mm or more, the mass collection efficiency is 85% or more, and the paint supply amount is 12,000 g or more, resulting in a large collection volume. This allows for a balance between collection performance and collection volume, and the filter element has a long lifespan.

[0116] Furthermore, a comparison of Comparative Examples 2 and 4 with Examples 1 to 4 revealed that the three-dimensional mesh structure with raised sections of 6 mm or more in height resulted in a mass collection efficiency of 85% or more and a large collection volume of 12,000 g or more of paint, demonstrating a balance between collection performance and collection volume, and resulting in a filter element with a long lifespan.

[0117] Furthermore, a comparison of Comparative Example 3 with Examples 1-4 revealed that a three-dimensional mesh structure with raised sections of 6 mm or more in height resulted in a mass collection efficiency of 85% or more and a large collection volume of 12,000 g or more of paint supplied, demonstrating a balance between collection performance and collection volume, and a longer lifespan than conventional paper exhaust filters.

[0118] (Examples 5-7, Comparative Example 5) Filter elements for Examples 5-7 and Comparative Example 5 were manufactured in the same manner as in Examples 1-4, except that the three-dimensional mesh structure and nonwoven fabric were simply laminated to form the filter material using the combinations shown in Table 4. The mass collection efficiency and paint supply amount of each filter element were measured using the method described above. The results are shown in Table 4. The results for Example 3 are also shown in Table 4.

[0119]

[0120] A comparison of Comparative Example 5 with Examples 3, 5-7 revealed that the three-dimensional mesh structure, composed of linear bodies with an average diameter of 100 μm or more, achieves a mass collection efficiency of 85% or more and a large collection volume of 12,000 g or more of paint, demonstrating a balance between collection performance and collection volume, resulting in a filter element with a long lifespan.

[0121] (Examples 8-16, Comparative Example 6) Filter elements for Examples 8-16 and Comparative Example 6 were manufactured in the same manner as in Examples 1-4, except that the three-dimensional mesh structure and nonwoven fabric were simply laminated to form the filter material using the combinations shown in Table 5. The mass collection efficiency and paint supply amount of each filter element were measured using the method described above. The results are shown in Table 5. The results for Example 3 are also shown in Table 5.

[0122]

[0123] A comparison between Comparative Example 6 and Examples 3, 8-16 shows that the bulk density is 25 kg / m³. ３ It was found that by having the following, or a nonwoven fabric with a thickness of 8 mm or more and a three-dimensional mesh structure, the mass method collection efficiency is 85% or more, and the paint supply amount is 12,000 g or more, resulting in a large collection volume, thus achieving both collection performance and collection volume, and providing a long-life filter element.

[0124] (Examples 17-19) After simply laminating the three-dimensional mesh structure 4 and the nonwoven fabric a to form a filter material, the filter elements of Examples 17-19 were manufactured in the same manner as in Examples 1-4, except that the pleating was performed under the conditions shown in Table 6. The mass collection efficiency and paint supply amount of each filter element were measured using the method described above. The results are shown in Table 6. The results of Example 3 are also shown in Table 6.

[0125]

[0126] Examples 3 and 17-19 showed that a pleat angle of 20-37° resulted in a mass collection efficiency of 85% or more and a large collection volume of 12,000 g or more of paint supply, demonstrating a balance between collection performance and collection volume, and resulting in a filter element with a long lifespan.

[0127] The filter material and filter element of the present invention not only have excellent collection performance, but also do not experience a rapid increase in pressure loss. As a result, they can collect a large amount of unwanted material before a predetermined pressure loss occurs, and have a long lifespan. Therefore, they are suitable for use as air conditioning filters or filter elements in buildings and factories. In particular, even when collecting mist from mist-containing gases such as oil mist and paint mist, the filter material and filter element of the present invention do not easily form a film or become clogged. As a result, they can collect a large amount of mist before a predetermined pressure loss occurs, and have a long lifespan. Therefore, they are suitable for use as air conditioning filters or filter elements in paint factories, painting sites, and factories that use cutting oils or lubricating oils.

[0128] 100 Filter material 1 Three-dimensional mesh structure 11 Raised portion 11a Side wall on the inlet side 11b Side wall on the outlet side 12 Recessed portion 2 Nonwoven fabric H Height of raised portion (thickness of the three-dimensional mesh structure) 20 Support 21 Projection 200 Filter element 210 Frame 210R Right side wall plate 210L Left side wall plate 210B Bottom plate S Fluid T Height of folds P Pitch of folds θ Fold angle 300 Final filter element 400 Airflow

Claims

1. A three-dimensional mesh structure consisting of linear bodies with an average diameter of 100 μm or more, having raised areas where the linear bodies are mountain-shaped and recessed areas where the linear bodies are valley-shaped, and a bulk density of 25 kg / m³ ３ A filter material comprising the following nonwoven fabric, characterized in that the height of the raised portion is 6 mm or more.

2. The filter material according to claim 1, characterized in that it has scattered raised portions.

3. The filter material according to claim 2, characterized in that the raised portions are scattered in a staggered pattern.

4. The bulk density of the three-dimensional mesh structure is 50 kg / m³. ３ The filter material according to any one of claims 1 to 3, characterized in that it is as follows.

5. A filter material according to any one of claims 1 to 4, characterized in that the thickness of the nonwoven fabric is 8 mm or more.

6. The filter material according to any one of claims 1 to 5, characterized in that the average fiber diameter of the nonwoven fabric is 20 μm or more.

7. A filter material comprising a three-dimensional mesh structure consisting of linear bodies with an average diameter of 100 μm or more, having raised portions where the linear bodies are mountain-shaped and recessed portions where the linear bodies are valley-shaped, and a nonwoven fabric with a thickness of 8 mm or more, characterized in that the height of the raised portions is 6 mm or more.

8. A filter element characterized in that the filter material according to any one of claims 1 to 7 is mounted on a frame in a folded state.

9. A filter element for mist-containing gas, characterized in that the filter material according to any one of claims 1 to 7 is mounted on a frame in a folded state.

10. The filter element according to claim 9, characterized in that the mist in the mist-containing gas is paint.

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