Filter

Abstract

A filter (1) is configured from a filter body (11) made solely from a non-woven fabric (21). The filter body (11) is provided with: an indicator portion (13) that displays or suggests a replacement time in association with use; and a ventilation portion (12), which is a part other than the indicator portion (13). The indicator portion (13) has a lower air permeability than the ventilation portion (12), the air permeability being 350 cc / cm2 / s or less. According to this configuration, because the indicator portion (13) is formed only from the non-woven fabric (21), the filter (1) is provided with the indicator portion (13) without using another material such as a resin membrane.

Description

filter

[0001] This invention relates to filters, and more particularly to filters used to prevent soiling in range hoods, air conditioners, air purifiers, ventilation fans and vents, HVAC systems, and the like.

[0002] As filters used to prevent dirt buildup in range hoods, exhaust fans, and vents, there are examples shown in Patent Document 1 (Japanese Patent Publication No. 2003-240297) and Patent Document 2 (Japanese Patent No. 4855240).

[0003] The replacement filter described in Patent Document 1 (Japanese Patent Publication No. 2003-240297) consists of a filter sheet made of nonwoven fabric that is attached to the underside of the range hood, and a replacement indicator formed on a part of the back surface of the filter sheet. The replacement indicator is a resin film that is not breathable and prevents the passage of oil fumes and the like.

[0004] The indicator filter described in Patent Document 2 (Japanese Patent No. 4855240) consists of a filter body made of nonwoven fabric that is attached to the underside of a range hood, and an indicator part formed on a part of the surface of the filter body. The indicator part is made of resin film and is non-breathable, preventing the passage of oil fumes and the like.

[0005] In the replacement filters described in Patent Document 1 (Japanese Patent Publication No. 2003-240297) and the indicator filters described in Patent Document 2 (Japanese Patent No. 4855240), the filter sheet and filter body gradually change color due to the adhesion of oil fumes, etc., whereas the replacement sign and indicator parts do not change color because they are not breathable and prevent the passage of oil fumes, etc. As a result, the replacement sign and indicator parts become visible as white on the front side of the filter as it is used, allowing the user to recognize that the filter has reached the time for replacement.

[0006] Japanese Patent Publication No. 2003-240297 Japanese Patent No. 4855240

[0007] However, with conventional filters as described above, it was necessary to use a resin film or membrane to form a replacement sign or indicator section in order to give the filter a function that indicates or suggests when it is time to replace it, which was costly.

[0008] Furthermore, resin films and membranes can discolor due to hydrolysis, heat, and UV degradation. Therefore, if the resin film or membrane discolors due to degradation, the replacement indicator or other visual cue may become visible even when the filter is unused, potentially leading to user confusion.

[0009] This invention was made to solve the above-mentioned problems, and aims to provide a filter that can determine when it needs to be replaced without using other materials such as resin films.

[0010] To achieve the above objective, the filter in the first aspect of this invention is a filter that is replaceably attached to an object and comprises a filter body made solely of nonwoven fabric, wherein the filter body includes an indicator part that indicates or suggests the time for replacement as it is used, and the indicator part has a lower degree of air permeability than the other parts of the air permeability section, with an air permeability of 350 cc / cm². ２ It is less than or equal to / s.

[0011] With this configuration, the indicator portion is formed solely from nonwoven fabric, which is effect 1.

[0012] In the second aspect of this invention, the filter, in the configuration of the invention in the first aspect, has a difference in air permeability between the indicator section and the ventilation section of 120 cc / cm². ２ It must be at least / s.

[0013] This configuration provides the benefit of making it easier to see the color difference between the indicator section and the ventilation section as the device is used.

[0014] In the third aspect of this invention, the filter, in the configuration of the invention in the second aspect, has a difference in air permeability between the indicator section and the ventilation section of 1800 cc / cm². ２ / s or less.

[0015] With this configuration, the third effect that dirt in air can be appropriately collected in the ventilation portion is obtained.

[0016] In the filter according to the fourth aspect of the present invention, in the configuration of the invention according to the first aspect or the second aspect, the nonwoven fabric comprises composite polyester fibers having a core-sheath structure in which a sheath portion is made of low-melting-point polyester and a core portion is made of high-melting-point polyester having a higher melting point than the low-melting-point polyester, and the indicator portion is a compressed portion formed by hot pressing.

[0017] With this configuration, the fourth effect that pressing time and heating temperature during hot pressing on the indicator portion can be reduced is obtained.

[0018] In the filter according to the fifth aspect of the present invention, in the configuration of the invention according to the fourth aspect, the nonwoven fabric is a thermal bond nonwoven fabric.

[0019] With this configuration, the fifth effect that the filter body is bonded by heat fusion is obtained.

[0020] In the filter according to the sixth aspect of the present invention, in the configuration of the invention according to the first aspect or the second aspect, the ventilation portion has an air permeability of 350 cc / cm ２ / s or more and 2000 cc / cm ２ / s or less.

[0021] With this configuration, the sixth effect that the ventilation portion changes color when oil fume passes through it is obtained.

[0022] In the filter according to the seventh aspect of the present invention, in the configuration of the invention according to the first aspect or the second aspect, the filter body has flame retardancy.

[0023] With this configuration, the seventh effect that the heat resistance of the filter body is improved is obtained.

[0024] In the filter according to the eighth aspect of the present invention, in the configuration of the invention according to the first aspect or the second aspect, the target object is a range hood or a ventilation fan.

[0025] With this configuration, effect 8 is obtained, that is, the indicator portion is less likely to discolor during use.

[0026] In the filter according to the ninth aspect of the present invention, in the configuration of the invention according to the first aspect or the second aspect, the object is an HVAC system.

[0027] With this configuration, effect 9 is obtained, that is, the indicator portion is less likely to discolor during use.

[0028] As explained above, the filter according to the first aspect of the present invention can achieve the above-mentioned effect 1, so that it can be a filter provided with an indicator portion without using other materials such as a resin film.

[0029] In addition to the effect of the invention according to the first aspect, the filter according to the second aspect of the present invention can achieve the above-mentioned effect 2, so that the filter replacement timing can be accurately determined.

[0030] In addition to the effect of the invention according to the second aspect, the filter according to the third aspect of the present invention can achieve the above-mentioned effect 3, so that it is suitable as a antifouling filter.

[0031] In addition to the effect of the invention according to the first aspect or the second aspect, the filter according to the fourth aspect of the present invention can achieve the above-mentioned effect 4, so that scorching is less likely to occur during hot pressing, and the quality stability is improved.

[0032] In addition to the effect of the invention according to the fourth aspect, the filter according to the fifth aspect of the present invention can achieve the above-mentioned effect 5, so that the formation of the indicator portion is facilitated.

[0033] In addition to the effect of the invention according to the first aspect or the second aspect, the filter according to the sixth aspect of the present invention can achieve the above-mentioned effect 6, so that it is a suitable filter for range hoods and the like.

[0034] The filter in the seventh aspect of this invention is suitable as a filter for preventing dirt buildup in range hoods and kitchen ventilation fans, as it provides the above-mentioned effect 7 in addition to the effects of the invention in the first or second aspect.

[0035] The filter in the eighth aspect of this invention is suitable as a filter for preventing dirt buildup in range hoods or ventilation fans because, in addition to the effects of the invention in the first or second aspect, the above-mentioned effect 8 is obtained.

[0036] The filter in the ninth aspect of this invention is suitable as a filter for an HVAC system because, in addition to the effects of the invention in the first or second aspect, the above-mentioned effect 9 is obtained.

[0037] This is a perspective view showing the installation state of the filter according to an embodiment of this invention. This is an enlarged view of the X portion shown in Figure 1, where (1) shows the state before use begins and (2) shows the state when it is time to replace the filter due to continued use. This is a diagram showing an enlarged structure of a part of the nonwoven fabric that constitutes the filter shown in Figure 1. This is an enlarged cross-sectional view along the line IV-IV in Figure 1, with the thickness exaggerated. This is a diagram showing the state in which the filter according to an embodiment of this invention is applied to an HVAC system.

[0038] Figure 1 is a perspective view showing the state of the filter being attached to the range hood according to an embodiment of this invention, and Figure 2 is an enlarged view of the X portion shown in Figure 1, where (1) shows the state before use begins and (2) shows the state when it is time to replace the filter due to continued use.

[0039] Referring to Figure 1, the range hood consists of a boot-shaped hood with an air intake on the inside. A metal filter 50 is attached to the opening of the air intake to prevent foreign objects from entering the inside of the air intake. Filter 1 is replaceably attached to the underside of the metal filter 50 via a magnet or the like (not shown), and consists of a filter body 11 made only of nonwoven fabric 21. Details of the nonwoven fabric 21 will be described later.

[0040] The filter main body 11 has a rectangular shape and includes a ventilation portion 12 which is a portion that exerts the filtering function of the filter 1, and an indicator portion 13 formed on a part of the filter main body 11 which displays or suggests a replacement time along with use.

[0041] The ventilation portion 12 refers to a portion of the filter main body 11 other than the indicator portion 13, and has an air permeability of 350 cc / cm ２ / s or more and 2000 cc / cm ２ / s or less. More preferably, it is 800 cc / cm ２ / s or less. With this configuration, when air containing oil fumes or the like passes through, the oil fumes and the like are sufficiently collected in the ventilation portion 12, and the ventilation portion 12 is discolored, so that the filter 1 is suitable for a range hood or the like.

[0042] Referring to Fig. 2, the indicator portion 13 is a portion that allows visual recognition and determination of the replacement time of the filter 1 caused by contamination of the filter 1 due to airborne contaminants such as oil fumes and dust, and is adjusted so that a difference in air permeability is partially formed in the nonwoven fabric 21 constituting the filter main body 11. In the present embodiment, the indicator portion 13 is formed by partially compressing the nonwoven fabric 21 by hot pressing that applies heat and pressure. The indicator portion 13 has lower air permeability than the ventilation portion 12 which is a portion other than the indicator portion 13. In the present embodiment, the indicator portion 13 has a quadrangular shape and has an air permeability of 320 cc / cm ２ / s or less. With this configuration, since the indicator portion 13 is formed only of the nonwoven fabric 21, the filter 1 including the indicator portion 13 can be obtained without using other materials such as a resin film. Also, unlike conventional techniques, materials other than air-impermeable nonwoven fabrics such as resin films do not need to be used, and the amount of such materials can be reduced, which is advantageous in terms of cost. Furthermore, since other materials such as resin films that may be discolored due to hydrolysis, heat, or ultraviolet degradation are not used, it is possible to reduce the possibility that the indicator portion is discolored in an unused state and causes a user to misidentify the replacement time.

[0043] Here, visibility of the indicator portion 13 before and after the start of use will be described.

[0044] Referring to Figure 2(1), in the state before use, both the indicator section 13 and the ventilation section 12 are made of nonwoven fabric 21 and are therefore the same color. As mentioned above, the indicator section 13 has a lower degree of air permeability than the ventilation section 12, and therefore does not easily collect dirt such as oil fumes from the air, so it does not easily change color even with continued use. On the other hand, the ventilation section 12 collects dirt such as oil fumes from the air and therefore changes color. In this way, because the indicator section 13 is configured so that only a part of the nonwoven fabric 21 obstructs air permeability, a difference in air permeability occurs between the indicator section 13 and the ventilation section 12, and a difference in the amount of oil fumes collected occurs according to the amount of air permeability. As a result, as time passes, as shown in Figure 2(2), the ventilation section 12 changes color, causing the indicator section 13 to become white and clearly readable. Therefore, the user will not misidentify the presence of the indicator section 13 before use and will be able to appropriately check the replacement time after use.

[0045] Next, the difference in air permeability between the indicator section 13 and the ventilation section 12 will be explained. As described above, the present invention provides the filter 1 with an indicator function (a function that displays or suggests the replacement time as it is used) by creating a difference in air permeability between the indicator section 13 and the ventilation section 12, such that the indicator section 13 has a lower air permeability than the ventilation section 12. The difference in air permeability between the indicator section 13 and the ventilation section 12 is 120 cc / cm ２ / s or more 1800cc / cm ２ Preferably it is less than or equal to / s, and 550 cc / cm³ ２ It is more preferable that the value be less than or equal to / s. The difference in air permeability between the indicator section 13 and the ventilation section 12 should be 120 cc / cm. ２ By setting the airflow rate to 1800 cc / cm² or higher, the difference in color between the indicator section 13 and the ventilation section 12 becomes easier to see during use, allowing for accurate determination of when to replace the filter 1. ２ By setting the temperature to less than / s, airborne dirt is properly collected in the ventilation section 12, making it suitable as a filter 1 for preventing dirt buildup.

[0046] Next, the nonwoven fabric 21 used in the filter 1 of this embodiment will be described.

[0047] Figure 3 shows a magnified view of a portion of the nonwoven fabric that makes up the filter shown in Figure 1.

[0048] Referring to Figure 3, the nonwoven fabric 21 is a thermal bonded nonwoven fabric manufactured by the thermal bonding method, and contains composite polyester fibers 22a and 22b having a core-sheath structure in which the sheath portions 24a and 24b are made of low-melting-point polyester and the core portions 25a and 25b are made of high-melting-point polyester with a higher melting point than the low-melting-point polyester, and the remaining modacrylic fibers 23. With this configuration, the density of the nonwoven fabric 21 is more easily changed by heat pressing, making it possible to reduce the pressing time and heating temperature when heat pressing the indicator portion 13. That is, in the case of a nonwoven fabric made of high-melting-point fibers, the indicator portion is difficult to form unless the heating temperature or heating time is increased during heat pressing, and depending on the setting conditions, there is a risk that the nonwoven fabric will burn. By including low-melting-point fibers in the nonwoven fabric 21, burning is less likely to occur when heat pressing, and the stability of the quality is improved. In addition, since it is a thermal bonded nonwoven fabric, the filter body 11 is bonded by heat fusion. Therefore, it is easy to impart shape by heat pressing, and the formation of the indicator portion 13 becomes easier. Furthermore, since modacrylic fibers are used as the remaining part of the composite polyester fibers, the filter body 11 becomes flame-retardant, making it suitable as a filter 1 for preventing dirt buildup in range hoods and kitchen ventilation fans.

[0049] Furthermore, the low-melting-point fiber containing the low-melting-point component is not limited to low-melting-point polyester. It is preferable that the nonwoven fabric be composed of composite fibers having a core-sheath structure, consisting of two components: a single polymer with a low melting point (whole-melting fiber), polyester, polypropylene, polyethylene, or the same or different type of low-melting-point fiber and a high-melting-point fiber. With this configuration, the fibers soften at a relatively low temperature, making it easy to form the desired shape by heat pressing. The nonwoven fabric may also be composed of side-by-side fibers formed by bonding the two components together, or composite fibers with other irregular cross-sections.

[0050] Furthermore, it is preferable that low-melting-point fibers constitute 10% to 80% by weight of the total amount of nonwoven fabric 21. This configuration facilitates the formation of compressed sections by heat pressing. It is even more preferable that low-melting-point fibers constitute 20% to 70% by weight. With this configuration, if the amount is 20% or more by weight, the formation of compressed sections by heat pressing becomes even easier, thus improving production efficiency during heat pressing. Furthermore, if the amount is 70% or less by weight, it is possible to mix other fibers into the remainder of the nonwoven fabric 21, making it possible to impart other desired functionalities such as flame retardancy to the nonwoven fabric 21.

[0051] When there is a difference in melting points between low-melting-point fibers and high-melting-point fibers, it is preferable that the melting point of the low-melting-point fibers be between 100°C and 140°C, the melting point of the high-melting-point fibers be between 200°C and 270°C, and the difference in melting points be 80°C or more. With this configuration, it is possible to reduce the heating temperature and the pressing time during heating press.

[0052] The nonwoven fabric 21 may be composed solely of a single fiber material, such as polyester fiber, that does not contain low-melting-point fibers. In that case, a compressed state can be formed in any desired area by performing a heat press at a temperature close to the melting point of the fiber, for example, 200°C.

[0053] The basis weight of the nonwoven fabric 21 that makes up the filter body 11 is 20 g / m². ２ More than 200g / m ２ Preferably, it is 20 g / m². ２ In the above cases, a difference in air permeability is likely to occur between the indicator section 13 and the ventilation section 12. 200 g / m ２ In the following cases, oil fumes and other contaminants can be sufficiently captured by the ventilation section 12. Therefore, the user can easily determine when it is time to replace the filter 1.

[0054] The thickness of the ventilation section 12 is not particularly limited, but it is preferable to set the thickness of the ventilation section 12 within the range of 1 mm to 10 mm. Also, if apparent density = (basis weight of nonwoven fabric) / (thickness of nonwoven fabric), the apparent density of the ventilation section 12 is 0.005 g / cm³. ３ 0.05g / cm or more３ It is preferable to set it within the following range. With this configuration, oil fumes and other contaminants are collected without compromising the ventilation performance of the range hood, allowing for proper ventilation. More specifically, 0.005 g / cm³ ３ In the above case, the ventilation section 12 can adequately capture oil fumes and the like. 0.05 g / cm³ ３ In the following cases, the ventilation section 12 will have appropriate ventilation capacity without hindering the ventilation performance of the range hood. Therefore, the filter 1 will adequately capture oil fumes generated during cooking while maintaining the ventilation performance of the range hood.

[0055] The thickness of the indicator portion 13 is not particularly limited, but it is preferable to set the thickness of the indicator portion 13 within the range of 0.015 mm to 0.8 mm. Also, the apparent density of the indicator portion 13 is 0.08 g / cm³. ３ 2g / cm or more ３ It is preferable to set the values ​​within the following range. With this configuration, the indicator unit 13 is less likely to discolor due to contamination from collected oil fumes, etc.

[0056] Next, we will explain the manufacturing process for obtaining such a filter 1.

[0057] First, composite polyester fibers are prepared such that they make up 30% to 70% by weight of the total amount of fibers to be blended, and modacrylic fibers are prepared for the remainder of 30% to 70% by weight. Then, the fibers to be blended are uniformly mixed, and the composite polyester fibers are softened and melted by the thermal bonding method, causing the blended fibers to bond together, thereby obtaining a thermal bonded nonwoven fabric (nonwoven fabric 21).

[0058] Next, an indicator portion 13 is formed on a portion of the nonwoven fabric 21 obtained in this manner by heating and compressing it. In this embodiment, a heat press machine is used to heat and compress a portion of the nonwoven fabric surface with a press bar heated to 90°C to 150°C at a pressure of 0.6 MPa for 0.5 to 1 second. The filter 1 of the present invention is obtained by forming an indicator portion 13, which is a compressed portion formed by heating and pressing, on a portion of the nonwoven fabric 21 in this way.

[0059] In the above embodiment, the indicator part had a rectangular shape, but it may be any geometric shape such as a heart shape, triangle shape, or star shape. Also, the indicator part is not limited to a mark, but may be letters, patterns, etc.

[0060] Furthermore, in the above embodiment, the filter body was attached to the object by a magnet. However, it may also be a structure in which the filter body is integrated with the frame by being bonded to the frame so as to cover the opening of the frame, with a frame body formed from metal foil such as aluminum foil and having a desired opening formed to correspond to the shape of the air intake of the range hood or the propeller of the ventilation fan. Alternatively, the end of such a metal foil frame body may be slidably engaged with the end of another similar frame body (for example, a structure in which a rim is formed on the ends of two frame bodies, and the rims of one frame body and the other frame body are slidably engaged with each other). With such a configuration, one frame body can be pre-shaped to correspond to the range hood or ventilation fan. Also, in the case of a structure composed of multiple frame bodies, the size of the filter can be changed by sliding the frame bodies. Therefore, it becomes possible to adjust the length of the filter according to the size of the range hood, improving ease of use.

[0061] Furthermore, while the above embodiment used a range hood as the target object, the present invention can be used in places where air enters and exits, such as ventilation devices like exhaust fans, indoor and outdoor vents, air conditioners, air purifiers, and the ventilation parts of bathroom doors, in addition to range hoods. By using the filter of the present invention on these objects, the indicator part becomes less prone to discoloration with use, making it suitable as a filter for preventing dirt buildup in range hoods, exhaust fans, and the like.

[0062] Furthermore, although the object in the above embodiment was a range hood, the present invention can also be applied to filters installed in HVAC (Heating, Ventilating, Air-Conditioning) systems. An HVAC system is a complex system consisting of multiple devices and control devices for controlling air temperature and ventilation, and is usually composed of outlets, heating systems, cooling systems, etc. These are usually integrated into a single system and are sometimes simply referred to as HVAC. Such an HVAC system incorporates an HVAC filter for the purpose of filtering the air. HVAC filters are used for air filtration in cases where they are attached to the HVAC unit, or attached to the back of the return grill in addition to the HVAC unit, or placed in any other location in the HVAC system. HVAC filters capture dust and dirt as the HVAC system operates and become dirty in about one to two months, so they are replaced periodically.

[0063] Figure 5 shows a filter according to an embodiment of this invention applied to an HVAC system.

[0064] To explain in detail, referring to Figure 5, the HVAC filter 5 is used by being removably attached to an HVAC unit (not shown) of the HVAC system. The HVAC filter 5 consists of a pleated HVAC filter base material 51, which is either a single-layer configuration of the filter according to the present invention or a multi-layer configuration combined with other filters, and a paper housing 52 that is removably attached to the HVAC unit while maintaining the shape of the HVAC filter base material 51. By using the filter of the present invention, the indicator part is less likely to discolor with use, making it suitable as an HVAC filter. When the HVAC filter base material 51 has a multi-layer configuration, the filter on the side into which the air flows is sometimes called the pre-filter layer, and the filter on the side of the object is sometimes called the main filter layer. Generally, the pre-filter layer is often configured at a relatively low density to improve shape retention while collecting coarse dust, and the main filter layer is often configured at a relatively high density to collect relatively fine particles. The filter according to the present invention can be applied to either the pre-filter layer or the main filter layer, or both, but it is convenient to apply it to the pre-filter layer, where the indicator part is easily visible and does not require a special configuration.

[0065] Furthermore, although thermal-bonded nonwoven fabric was used in the above embodiment, there are no limitations on the manufacturing method of the nonwoven fabric, and nonwoven fabrics manufactured by known methods such as chemical bonding or needle punching can be used. In addition, multiple bonding methods may be used in combination. For example, thermal bonding and needle punching can be used in combination. In this way, the thickness of the filter body can be adjusted by the needle punching method to make it thinner than the nonwoven fabric manufactured by the thermal bonding method, so that a filter suitable for the installation location and the conditions of the object can be manufactured.

[0066] Furthermore, in the above embodiment, the filter consisted of a filter body, but it may also include components other than the filter body. Components other than the filter body may include adhesive layers, hook-and-loop fasteners, and other components other than nonwoven fabric. For example, if the filter body has an adhesive layer on the side that is attached to the object, and a release sheet on top of that, it can be attached by peeling off the release sheet and sticking it to the object like a sticker, and it can also be easily replaced after use.

[0067] Furthermore, in the above embodiment, the indicator unit indicated the replacement time by making the user visually aware of a specific shape. However, it may also indicate the replacement time by making the user visually aware of a sign, such as a string of characters like "Please replace it."

[0068] Furthermore, in the above embodiment, the difference in air permeability between the indicator section and the ventilation section is 120 cc / cm². ２ / s or more 1800cc / cm ２ It was less than / s, but 120 cc / cm³ ２ Less than / s or 1800cc / cm³ ２ It's also acceptable if it's greater than / s.

[0069] Furthermore, in the above embodiment, the air permeability of the ventilation section is 350 cc / cm². ２ / s or more 2000cc / cm ２ It was less than / s, but 350 cc / cm ２ Less than / s or 2000cc / cm³ ２ It's also acceptable if it's greater than / s.

[0070] Furthermore, although the filter body in the above embodiment was flame-retardant, it does not need to be flame-retardant.

[0071] Furthermore, although modacrylic fiber was used as the flame-retardant fiber in the above embodiment, other flame-retardant fibers such as flame-retardant acrylic fiber or flame-retardant polyester fiber, fibers blended with flame-retardant functional agents, inorganic additives such as antimony trioxide, antimony pentoxide, magnesium compounds such as magnesium oxide or magnesium hydroxide, fibers supported with fine particles or components of phosphorus-based or halogen-based flame retardants, or fibers to which an appropriate amount of fatty acid metal salts such as aluminum stearate is attached may also be used. With this configuration, the desired flame retardancy can be imparted to the nonwoven fabric, resulting in a nonwoven fabric suitable for manufacturing filters that preferably have flame retardancy.

[0072] Furthermore, the modacrylic fiber mentioned above is a fiber made of a long-chain synthetic polymer in which the repeating units of acrylonitrile account for 35% or more and less than 85% by mass ratio. It is copolymerized with vinylidene chloride and vinyl chloride, and possesses self-extinguishing properties, such as extinguishing the atmosphere by releasing halogen-based gases when burned. By using such modacrylic fiber as a flame-retardant fiber, a nonwoven fabric that exhibits sufficient flame retardancy is produced, making it possible to manufacture filters with sufficient flame retardancy.

[0073] Flame-retardant acrylic fibers are fibers made of long-chain synthetic polymers containing 85% or more by mass of repeating acrylonitrile units. When copolymerized with vinylidene chloride or vinyl chloride, and when inorganic flame retardants such as antimony compounds are added, they possess self-extinguishing properties, making it possible to manufacture nonwoven fabric filters with flame retardancy similar to modacryl fibers. Alternatively, filters may be manufactured using acrylic fibers other than flame-retardant acrylic fibers, combined with other flame-retardant fibers.

[0074] Furthermore, the remainder described above may include not only flame-retardant fibers but also other fibers. For example, rayon fibers and polyvinyl alcohol (PVA) fibers are examples, and when these are included as other fibers, it is possible to prevent the molten resin from dripping during combustion. Also, as long as it does not adversely affect the effects of the present invention, a flame retardant such as a phosphorus-based water-soluble flame retardant compound may be applied to the fibers of the nonwoven fabric of the present invention by spraying or other means, either instead of using flame-retardant fibers or in combination with flame-retardant fibers to improve flame retardancy. In this case as well, the bonding between the fibers constituting the nonwoven fabric is mainly due to thermal bonding of the fibers by the low-melting-point polyester in the sheath portion of the composite polyester fiber.

[0075] Furthermore, in the above embodiments, the low-melting-point polyester and high-melting-point polyester are not particularly limited, and for example, polyethylene terephthalate (PET) can be used. Polyester is a polymeric substance having ester bonds in its molecule, and in addition to PET, examples include polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc. Note that different types of polyester may be used for the low-melting-point polyester and the high-melting-point polyester. Also, copolymer components may be included in the polymer structure to improve the properties of the fiber.

[0076] Alternatively, instead of or in combination with the above-mentioned composite polyester fibers, composite fibers with a core-sheath structure having polyethylene or polypropylene in the sheath portion, fully melted fibers of a single polymer having a low melting point component, or side-by-side fibers with two components bonded together may be used.

[0077] In addition to the fibers mentioned above, rayon fibers, polyvinyl alcohol fibers, acrylic fibers, etc. may be included to improve the functionality, texture, and other properties of the nonwoven fabric filter.

[0078] Furthermore, in the above embodiment, the indicator portion was formed by heat pressing a part of the nonwoven fabric surface, but the location and method of heat pressing are not limited. Figure 4 is an enlarged cross-sectional view along the line IV-IV in Figure 1, with the thickness exaggerated. When heat pressing is applied to a part of the nonwoven fabric surface, as shown in Figure 4(1), the surface is indented and the compressed portion extending from the surface to the back surface is formed as the indicator portion 13. When heat pressing is applied to a part of the back surface of the nonwoven fabric, as shown in Figure 4(2), the back surface is indented and the compressed portion extending from the back surface to the surface is formed as the indicator portion 33. When heat pressing is applied from both the surface and the back surface, as shown in Figure 4(3), both the surface and the back surface are indented and the compressed portion extending from the surface to the back surface is formed as the indicator portion 36. When heat pressing is applied to a part of the nonwoven fabric surface, as shown in Figure 4(4), the surface may be indented and the area near the surface may be compressed to form the indicator portion 39. When heat pressing is applied to a part of the nonwoven fabric surface, as shown in Figure 4(5), the indicator portion 42 may be formed with a gently indented cross-sectional shape. When the nonwoven fabric is heat-pressed from both the front and back surfaces, as shown in Figure 4(6), both the front and back surfaces may be gently indented, and the compressed portion extending from the front to the back surface may be formed as an indicator portion 43.

[0079] The present invention will be described in detail below based on examples. However, the embodiments of the present invention are not limited to these examples.

[0080] Test specimens of the embodiments and comparative examples of the present invention were prepared, and these specimens underwent air permeability tests to measure air permeability and visibility tests to evaluate the visibility of the indicator part before and after use.

[0081] (Preparation of test specimens) First, thirteen types of nonwoven fabrics with different weights and compositions were prepared, each measuring 350 mm in the short direction and 600 mm in the long direction.

[0082] Furthermore, for measuring the basis weight, three pieces of nonwoven fabric cut to the dimensions of a 100 mm x 100 mm test specimen were taken, and the mass (g) of each was measured using an electronic balance. The average value of each of the three pieces was then calculated. Against this average value, the area of ​​the test specimen (100 mm x 100 mm = 0.01 m²) was used. ２ The value per sheet was determined by dividing by ).

[0083] Furthermore, the nonwoven fabrics used to constitute the filters in Examples 1 to 9 and Comparative Examples 1 to 2 were composite polyester fibers having a core-sheath structure, with the sheath portion having a melting point 80°C or more lower than the polyester fibers in the core. The nonwoven fabrics used to constitute the filters in Example 10 and Reference Example 1 were nonwoven fabrics made of a single polyester fiber.

[0084] In Examples 1 to 3 and Comparative Example 1, a nonwoven fabric was used in which, out of a total weight of 100% of the nonwoven fabric, 70% by weight was composed of composite polyester fibers and 30% by weight was composed of modacrylic fibers. Furthermore, in Examples 1 to 3 and Comparative Example 1, the nonwoven fabric was manufactured by the thermal bonding method.

[0085] In Examples 4 to 6 and Comparative Example 2, a nonwoven fabric was used in which, based on a total weight of 100% of the nonwoven fabric, 30% by weight of composite polyester fibers, 30% by weight of flame-retardant polyester fibers, 30% by weight of polyester fibers, and 10% by weight of polyvinyl alcohol fibers were used. Furthermore, in Examples 4 to 6 and Comparative Example 2, the nonwoven fabric was obtained by the thermal bonding method, and then its thickness was adjusted by the needle punching method.

[0086] In Examples 7 to 9, a nonwoven fabric was used in which, out of a total weight of 100% of the nonwoven fabric, 70% by weight was composed of composite polyester fibers and 30% by weight was composed of modacrylic fibers. In addition, in Examples 7 to 9, the nonwoven fabric was obtained by the thermal bonding method, and then its thickness was adjusted by the needle punching method.

[0087] In Example 10, a nonwoven fabric made of polyester fibers was used. In Example 10, the nonwoven fabric was obtained by a chemical bonding method, and then its thickness was adjusted by a needle punching method.

[0088] Reference Example 1 used a nonwoven fabric made of polyester fibers. Furthermore, in Reference Example 1, the nonwoven fabric was obtained by a chemical bonding method, and then its thickness was adjusted by a needle punching method. Of these test specimens, portions of the nonwoven fabrics from Examples 1 to 10 and Comparative Examples 1 to 2 were heated and compressed using a heat press machine's press bar at a pressure of 0.6 MPa, resulting in 2.5 cm square (6.25 cm) sections. ２ By forming an indicator section having a rectangular shape, the filter shown in Figure 1 above was obtained.

[0089] In Examples 1 and 4, the material was heated and compressed at 100°C for 0.5 seconds.

[0090] In Examples 2 and 5, the material was heated and compressed at 135°C for 0.5 seconds.

[0091] In Examples 3 and 6 through 8, the material was heated and compressed at 150°C for 0.5 seconds.

[0092] In Example 9, the material was heated and compressed at 150°C for 1 second.

[0093] In Example 10, the material was heated and compressed at 190°C for 1 second.

[0094] In Comparative Example 1 and Comparative Example 2, the material was heated and compressed at 95°C for 0.5 seconds.

[0095] In Reference Example 1, a filter was obtained by laminating a 2.5 cm square resin film made of polyethylene resin onto the surface of a nonwoven fabric to form an indicator section.

[0096] Table 1 shows the composition of these nonwoven fabrics, the heat compression time, and the heating temperature.

[0097] (Air permeability) In accordance with JIS L 1096 Method A (Fragile method), the air permeability (cc / cm²) of each filter is measured. ２ The sec) was measured. Measurements were also taken for the indicator section and the ventilation section. The measurements were performed using a measuring instrument, model FP2, manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0098] The test specimen used for measurement is prepared by cutting a 50 mm x 50 mm specimen from the filter. This specimen is then placed in the measuring instrument.

[0099] The measuring instrument has a measuring opening area of ​​5 cm². ２ (The diameter of the measurement opening is approximately 25 mm.) However, since the size of the indicator part is 2.5 cm square, measurements were taken using a jig with a diameter of 20 mm in this measurement opening. The same jig was used to measure the ventilation part. Specifically, a 20 mm diameter opening (opening area 3.14 cm²) was placed in the center of a 100 mm square stainless steel plate with a thickness of 1 mm. ２ A jig was prepared with the following characteristics: The test specimen was placed on the measuring opening, and the jig was set so that the test specimen was positioned between the measuring opening and the jig. Then, the jig and the test specimen were clamped down from above and subjected to measurement. Other conditions were measured according to JIS L 1096 Method A (Fragile method).

[0100] Furthermore, the air permeability is calculated based on the actual measurement area of ​​5 cm², compared to the value displayed by this measuring instrument. ２ Therefore, multiplying by 5, the opening area of ​​the jig is 3.14 cm². ２ Therefore, it was obtained by dividing by 3.14 and converting.

[0101] (Visibility of the indicator section: range hood) Using 13 types of filters from Examples 1 to 10, Comparative Examples 1 to 2, and Reference Example 1, the filters were attached to the surface of a metal filter installed in a range hood using magnets, and the following tests were conducted. The range hood used in the tests was a deep-type range hood manufactured by Fuji Kogyo Co., Ltd. (model name: BDR-3HL-601ABK), and the suction was operated in strong mode. In addition, magnets were placed one at each of the four corners of the filter for attachment.

[0102] 1. The visibility filter of the indicator section was visually inspected before use, and the indicator section was visually confirmed. If the presence of the indicator section was not visible, it was evaluated as "○" (suitable), and if the presence of the indicator section was visible, it was evaluated as "×" (unsuitable).

[0103] 2. Visibility of the indicator after use: A frying pan (outer diameter 26 cm, depth 5 cm) placed on a stove was preheated. With the surface temperature at 260°C, 1.35 cc of water and 1.38 cc of oil (manufactured by Nisshin Oillio, product name: Nisshin Canola Oil) were dripped from above the frying pan. This dripping was continued for 1 hour, generating oil fumes for 1 hour.

[0104] After one hour, the stove was turned off to stop the generation of oil fumes, and the filter attached to the range hood was visually inspected. If the indicator part could be visually confirmed by a difference in discoloration on a part of the filter body, it was evaluated as "○" (suitable). If there was no difference in discoloration due to oil fumes and the indicator part could not be visually confirmed, it was evaluated as "×" (unsuitable).

[0105] The results are shown in Table 2 below.

[0106] Refer to Table 2, and the air permeability of the indicator section is 350 cc / cm². ２ In Comparative Examples 1 and 2, which exceeded / s, the indicator part was not visible after use, and the visibility of the indicator part after use was poorly evaluated. In contrast, the air permeability of the indicator part was 350 cc / cm². ２ Examples 1 to 10, with values ​​below / s, were found to yield good results, with the indicator not being visible before use and being visible after use.

[0107] Reference Example 1, which has an indicator part made of a resin film, had a poor evaluation of the visibility of the indicator part before use, whereas Examples 1 to 10, which have an indicator part made of a filter body made only of nonwoven fabric without using a resin film, did not have an indicator part visible before use, and it was confirmed that this resulted in good results.

[0108] (Visibility of indicator section: HVAC) Using 13 types of filters from Examples 1 to 10, Comparative Examples 1 to 2, and Reference Example 1, HVAC filters with a shape similar to HVAC filter 5 (see Figure 5, etc.) were manufactured. In manufacturing the HVAC filters, a composite filter was prepared as the HVAC filter substrate by laminating a pre-filter layer and a main filter layer. For the manufacture of the composite filter, the 13 types of filters from the aforementioned examples and comparative examples were prepared as the pre-filter layer, and the main filter layer was manufactured using the meltblown method with a basis weight of 20 g / m². ２ We prepared a meltblown nonwoven fabric by manufacturing a polypropylene nonwoven fabric and then performing electrostatic treatment using corona discharge.

[0109] Next, a hot-melt polyurethane resin adhesive was sprayed onto one side of each pre-filter layer and bonded to the main filter layer to prepare a two-layer HVAC filter substrate. In addition, a wire mesh was bonded to the surface of the main filter layer (meltblown nonwoven fabric) as a reinforcing layer.

[0110] Next, a pleating process was carried out to create an HVAC filter substrate with a pleat height of 1 inch (2.54 cm) and a pleat pitch of 0.4 inches (1.016 cm).

[0111] Finally, the HVAC filter substrate was set in a paper casing to create an HVAC filter measuring 16 inches (40.64 cm) x 16 inches (40.64 cm) x 1 inch (2.54 cm) in height.

[0112] The HVAC filter prepared in this manner was attached to the HVAC unit, and the following tests were conducted.

[0113] 1. Visibility of the indicator before use: The pre-filter layer side of the HVAC filter was visually inspected to confirm the presence of the indicator. If the presence of the indicator was not visible, it was evaluated as "○" (suitable), and if the presence of the indicator was visible, it was evaluated as "×" (unsuitable).

[0114] 2. Visibility of the indicator after use After installing the HVAC filter into the HVAC unit, the HVAC system was operated under normal operating conditions for one month. Then, the HVAC system was stopped, and the pre-filter layer of the HVAC filter attached to the HVAC unit was visually inspected. If the indicator could be visually confirmed by a difference in discoloration on a part of the pre-filter layer, it was evaluated as "○" (suitable). If there was no difference in discoloration due to dust, etc., and the indicator could not be visually confirmed, it was evaluated as "×" (unsuitable).

[0115] The results are shown in Table 3 below.

[0116] Refer to Table 3, and the air permeability of the indicator section is 350 cc / cm². ２ In Comparative Examples 1 and 2, which exceeded / s, the indicator part was not visible after use, and the visibility of the indicator part after use was poorly evaluated. In contrast, the air permeability of the indicator part was 350 cc / cm². ２ Examples 1 to 10, with values ​​below / s, were found to yield good results, with the indicator not being visible before use and being visible after use.

[0117] Reference Example 1, which has an indicator part made of a resin film, had the indicator part visible before use, and the visibility of the indicator part before use was poorly evaluated. In contrast, Examples 1 to 10, which are HVAC filters that use the filter of the present invention, which has an indicator part made of a filter body made only of nonwoven fabric without using a resin film, as a pre-filter layer, did not have an indicator part visible before use, and it was confirmed that this resulted in good results.

[0118] As described above, the filter according to the present invention is suitable for preventing dirt buildup in, for example, range hoods, air conditioners, air purifiers, ventilation fans and vents, HVAC systems, and the like.

Claims

1. A filter (1, 31, 34, 37, 40) that is replaceably attached to an object and comprises a filter body (11) made solely of nonwoven fabric (21), wherein the filter body is equipped with an indicator section (13, 33, 36, 39, 42, 43) that indicates or suggests the time for replacement as it is used, and the indicator section has a lower degree of air permeability than the other parts, which are the ventilation sections (12, 32, 35, 38, 41), with an air permeability of 350 cc / cm². ２ A filter that is less than or equal to / s.

2. The difference in air permeability between the indicator section and the ventilation section is 120 cc / cm². ２ The filter according to claim 1, wherein the value is / s or greater.

3. The difference in air permeability between the indicator section and the ventilation section is 1800 cc / cm². ２ The filter according to claim 2, wherein the value is less than or equal to / s.

4. The filter according to claim 1 or 2, wherein the nonwoven fabric includes a composite polyester fiber (22) having a core-sheath structure in which the sheath portion (24) is made of low-melting-point polyester and the core portion (25) is made of high-melting-point polyester with a higher melting point than the low-melting-point polyester, and the indicator portion is a compressed portion formed by heating and pressing.

5. The filter according to claim 4, wherein the nonwoven fabric is a thermal bonded nonwoven fabric.

6. The ventilation section has an air permeability of 350 cc / cm². ２ / s or more 2000cc / cm ２ The filter according to claim 1 or claim 2, wherein the value is less than or equal to / s.

7. The filter body is flame-retardant, as described in claim 1 or claim 2.

8. The filter according to claim 1 or claim 2, wherein the object is a range hood or a ventilation fan.

9. The filter according to claim 1 or claim 2, wherein the object is an HVAC system.

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