Filter Structure

Abstract

To provide a filter structure which has good mountability under both normal temperature and low temperature conditions, does not fall off from a metal filter, and has no adhesive residue.SOLUTION: A filter structure adhered to an object to filter passing gas comprises a filter layer made of a sheet-like member having air permeability, and an adhesive layer formed on at least a part of one surface of the filter layer for adhering to an object. The adhesive layer is formed by an acrylic hot-melt adhesive, and a ratio K1 / K2 of a maximum peeling load K1 at 25°C to a maximum peeling load K2 at 5°C is in the range of 1 to 6. When attached to the object under temperature conditions of 25°C and 5°C, it does not fall off from the object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a filter structure that is attached to an object such as a range hood, an air conditioner, an air purifier, or an air vent, for filtering gas passing therethrough. [Background technology]

[0002] Filter structures for filtering air passing through metal filters or straightening plates of range hoods, air intakes of air conditioners and air purifiers, indoor and outdoor vents, etc. are described in JP 2002-85927 A (Patent Document 1), JP 2017-15297 A (Patent Document 2), etc. The filter structures described in these documents have a structure in which an adhesive layer is formed on one side of a sheet-like filter layer made of nonwoven fabric or the like. In addition, a thin release sheet is usually attached to the surface of the adhesive layer. Furthermore, a filter structure using an acrylic hot melt adhesive as the adhesive layer is described in JP 2016-36801 A (Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-85927 A [Patent Document 2] JP 2017-15297 A [Patent Document 3] JP 2016-36801 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to attach the filter structure as described in Patent Documents 1 to 3 to an object such as a range hood or an air conditioner, the release film attached to the surface of the adhesive layer is removed to expose the adhesive surface of the adhesive layer, and then the adhesive surface is aligned to the attachment location while keeping the entire filter structure in an expanded state, and then pressure-bonded. Here, when an acrylic hot melt adhesive is used as the adhesive layer as in Patent Document 3, the filter structure has good adhesion when attached to the metal filter of a range hood at room temperature (25°C), so it is not detached from the metal filter. However, for example, when the filter structure is attached to the metal filter of a range hood installed in a kitchen that has not been used for a long time in a low temperature environment such as winter, the filter structure may fall off from the metal filter. In addition, it may not be possible to attach the filter structure to the metal filter at all. This is because the adhesiveness of conventional adhesives changes greatly between room temperature and low temperature, so when the surface temperature of the metal filter reaches about 5°C in cold seasons, the adhesiveness is significantly reduced due to the temperature drop of the adhesive itself. To address this issue, it is possible to prevent the filter structure from falling off during cold seasons by improving the adhesive's adhesion at low temperatures. However, in this case, improving the adhesive's adhesion at low temperatures can result in a problem that when the filter structure is left attached to the metal filter at room temperature for a long period of time and then peeled off, some of the adhesive remains attached to the metal filter (glue residue).

[0005] Such problems are more likely to occur as the external dimensions of the filter structure become larger. Generally, filter structures for range hoods and air conditioners have relatively large external dimensions of several tens of centimeters in both length and width, making the above problems more likely to occur.

[0006] In view of the above-mentioned conventional problems, the present invention aims to provide a filter structure which has good attachment properties under both room temperature and low temperature conditions, does not fall off from the metal filter, and leaves no adhesive residue. [Means for solving the problem]

[0007] In order to achieve the above object, the invention described in claim 1 is a filter structure for attaching to an object to filter gas passing through, the filter structure comprising a filter layer made of a breathable sheet-like member, and an adhesive layer for attachment to the object formed on at least a part of one side of the filter layer, the adhesive layer being formed of an acrylic hot melt adhesive, the ratio K1 / K2 of the maximum peel load K1 at 25°C to the maximum peel load K2 at 5°C being within a range of 1 to 6, and the adhesive layer will not fall off from the object when attached to the object under temperature conditions of 25°C and 5°C, the adhesive layer having a maximum peel load K1 at 25°C in a range of 0.01 to 0.18 N / mm and a maximum peel load K2 at 5°C in a range of 0.01 to 0.05 N / mm. It also leaves no adhesive residue when peeled off from the object after being left attached for one month at a temperature of 25°C. It is something.

[0008] With this configuration, the adhesive strength of the adhesive layer made of the acrylic hot melt adhesive changes less compared to conventional filter structures even when the temperature during attachment is different between 25° C. and 5° C., and stable adhesive strength is obtained, so the filter will not fall off from the target object under either temperature conditions of 25° C. or 5° C. Furthermore, appropriate adhesive strength to the target object, such as a metal filter for a range hood, can be obtained under different temperature conditions of 25° C. and 5° C. The invention described in claim 2 is a filter structure for attaching to an object to filter gas passing through, comprising a filter layer made of a breathable sheet-like member and an adhesive layer for attaching to the object, formed on at least a part of one side of the filter layer, the adhesive layer being formed of an acrylic hot melt adhesive, and having a maximum peel load K at 25°C when attached to the object. 1 and maximum peel load K at 5℃ 2 Compared to K 1 / K 2 is within the range of 1 to 6, and when applied to an object under temperature conditions of 25°C and 5°C, the adhesive layer does not fall off from the object, and the maximum peel load K 1 is in the range of 0.01 to 0.18N / mm, and the maximum peel load K at 5°C is 2 The adhesive strength is in the range of 0.01 to 0.05 N / mm, the length of at least one of the filter layers is 25 cm or more, and no adhesive residue is left when the filter is peeled off from the object after being left attached for one month at a temperature of 25°C. With this configuration, the adhesive strength of the adhesive layer made of the acrylic hot melt adhesive changes less compared to conventional filter structures even when the temperature during attachment is different between 25° C. and 5° C., and stable adhesive strength is obtained, so the filter will not fall off from the target object under either temperature conditions of 25° C. or 5° C. Furthermore, appropriate adhesive strength to the target object, such as a metal filter for a range hood, can be obtained under different temperature conditions of 25° C. and 5° C.

[0011] Claim 3 The invention described is as follows: Claim 1 or claim 2 In the configuration of the described invention, the object has a surface that is plated with metal or painted with resin.

[0012] With this configuration, the object to which the filter structure is applied is limited to an object whose surface is plated or painted with resin.

[0013] Claim 4 The invention described is as follows: Any of claims 1 to 3 In the configuration of the described invention, the coating rate of the adhesive forming the adhesive layer on one side of the filter layer is 5 to 95%.

[0014] With this configuration, the coating rate of the adhesive on one surface of the filter layer is in the range of 5 to 95%.

[0015] Claim 5 The invention described is as follows: 4 In the configuration of the invention described in any one of the above, at least one of the filter layers has a length of 25 cm or more.

[0016] When configured in this manner, the filter structure becomes a relatively large product. Effect of the Invention

[0017] In the invention described in claim 1, the adhesive layer is formed of an acrylic hot melt adhesive, and the ratio K1 / K2 of the maximum peel load K1 at 25°C to the maximum peel load K2 at 5°C is within a predetermined range, so that the filter structure will not fall off from the object when attached to the object under both temperature conditions of 25°C and 5°C, and it is possible to attach the filter structure to the object with an appropriate adhesive strength. In addition, when the filter structure is peeled off from a metal filter or the like after long-term attachment and use, no adhesive residue is left. Furthermore, since the maximum peel loads K1 and K2 of the adhesive layer under each temperature condition of 25°C and 5°C are set within an appropriate range, the filter structure will not easily fall off or partially peel off from the object after being attached to the object even under different temperature conditions, and when replacement or other such is necessary, it is possible to easily peel off the filter structure from the object without leaving any adhesive residue. The invention described in claim 2 is a pressure-sensitive adhesive layer formed of an acrylic hot melt pressure-sensitive adhesive, and has a maximum peel load K at 25°C. 1 and maximum peel load K at 5℃ 2 Compared to K 1 / K 2 is within a specified range, the filter structure will not fall off from the object when attached to the object under both temperature conditions of 25°C and 5°C, and it is possible to attach the filter structure to the object with an appropriate adhesive strength. In addition, when the filter structure is peeled off from a metal filter or the like after long-term attachment and use, no adhesive residue is left. Furthermore, the maximum peel load K of the adhesive layer under each temperature condition of 25°C and 5°C 1 、K 2 Since is set within an appropriate range, there is no risk of the filter structure easily falling off or partially peeling off from the object after being attached to the object, even under different temperature conditions, and further, when replacement or the like becomes necessary, the filter structure can be easily peeled off from the object without leaving any glue residue.

[0019] Claim 3 The invention described is as follows: Claim 1 or claim 2 In addition to the effects of the invention described above, if the filter structure is applied to an object whose surface is plated or painted with resin, then when the filter structure is attached to the object and then removed, no adhesive residue is left, or the amount of adhesive residue can be reduced.

[0020] Claim 4 The invention described is as follows: Any of claims 1 to 3 In addition to the effects of the invention described above, the area ratio of the adhesive layer formed on one side of the filter layer is set within a specific range, so that the balance between the adhesive strength of the entire filter structure and the breathability of the filter layer can be appropriately set depending on the object to which it is attached.

[0021] Claim 5 The invention described is as follows: 4 In addition to the effects of the invention described in any one of the above, since the object of application of the present invention is a filter structure having a relatively large outer dimension that is prone to falling off or partial peeling from the object due to its own weight, the advantage that the filter structure will not fall off from the object when attached to the object under either temperature condition of 25°C or 5°C becomes more apparent. [Brief description of the drawings]

[0022] [Figure 1] 1 is a front view showing an example of a filter structure according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing an example of a manufacturing apparatus for manufacturing a filter structure according to an embodiment of the present invention. [Diagram 3] 4 is a schematic diagram showing another embodiment of a manufacturing apparatus for manufacturing a filter structure according to the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] 1 is a front view showing an example of a filter structure according to an embodiment of the present invention. This filter structure F is attached to an object to filter passing gas, and includes a sheet-like filter layer S that filters the passing air, and an adhesive layer N formed on at least a part of one side of the filter layer S to be attached to the object. The filter structure F of this example is characterized in that the adhesive layer N is formed from an acrylic hot melt.

[0024] The filter layer S in this embodiment is made of, for example, a nonwoven fabric, a woven fabric, a knitted fabric, etc. In order to achieve both dust collection and gas circulation and to ensure practical strength, the thickness is set to 0.3 to 15.0 mm and the basis weight is set to 20 to 200 g / m 2 The thickness is preferably less than 0.3 mm or the basis weight is preferably less than 20 g / m 2 If the thickness is less than 15.0 mm, the strength is insufficient for practical use and the collection function may not be sufficient. 2 If the resistance exceeds this value, the gas flow resistance increases, and the practical use of the air filter may be impaired. The material of the filter layer S may be, but is not limited to, polyester such as PET, polypropylene or a copolymer mainly composed of propylene, acrylic including modacrylic, etc. When the filter structure of the present invention is used as a filter structure for a range hood, it is preferable that the filter layer S is made of, for example, a nonwoven fabric, and that the fibers are made of flame-retardant fibers or that the fibers are treated with a flame retardant (for example, by attaching a fatty acid metal salt such as aluminum stearate to the fibers).

[0025] The adhesive layer N is formed of an acrylic hot melt on at least a part of one side of the filter layer S. The acrylic hot melt has properties such as high cohesiveness, excellent weather resistance and moisture resistance, and does not require much tackifier. The adhesive layer N formed on the filter layer has a property that the ratio K1 / K2 [= maximum peel load N / mm (25°C) ÷ maximum peel load N / mm (5°C)] of the maximum peel load K1 at 25°C to the maximum peel load K2 at 5°C is within a range of 1 to 6. By having such a property, the filter structure F does not fall off from the object when it is attached to the object under both temperature conditions of 25°C and 5°C. The maximum peel load K1 of the pressure-sensitive adhesive layer N at 25° C. is preferably set in the range of 0.01 to 0.18 N / mm, more preferably in the range of 0.05 to 0.13 N / mm, and the maximum peel load K2 of the pressure-sensitive adhesive layer N at 5° C. is preferably set in the range of 0.01 to 0.05 N / mm, more preferably in the range of 0.02 to 0.04 N / mm. Setting the pressure-sensitive adhesive layer N in this manner makes it possible to provide a filter structure F that can reliably prevent the pressure-sensitive adhesive layer N from falling off the object under both temperature conditions of 25° C. and 5° C., and that can also solve the problem of adhesive residue at 25° C.

[0026] As one means for imparting the above-mentioned characteristics to the adhesive layer, various physical properties can be adjusted by adding one or more of the components shown below to the acrylic hot melt that forms the adhesive layer. (Tackifier): Improves adhesion of the adhesive layer to the filter layer Tackifying resins such as rosin resins, terpene resins, (hydrogenated) petroleum resins, coumarone-indene resins, hydrogenated aromatic copolymers, styrene resins, phenolic resins, and xylene resins; plasticizers such as phthalates, adipates, sebacates, and other fatty acid esters, paraffins, epoxy polymer plasticizers, phosphates, phosphites, acrylic oligomers, polyisoprene, process oils, naphthenic oils, polyester polyols, polyether polyols, and polyol compounds; other polymers such as ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate copolymers, and polyvinyl acetate. (Softener): Prevents loss of adhesive strength at low temperatures, improves coating properties (suppresses stringiness), and suppresses adhesive residue Mineral oils (synthetic oils) such as petroleum hydrocarbons, vegetable oils, animal oils, paraffins, terpenoids, fatty acids, fatty acid esters, alcohol, honey, crotamiton The above components may be used alone or in combination of two or more.

[0027] The means for applying the acrylic hot melt to the filter layer may be, but is not limited to, a roll coating method using a coating roll, a spray coating method, an inkjet method, a die coating method, a screen printing method, or the like.

[0028] The procedure for producing the filter structure by the roll coating method will be described below.

[0029] Fig. 2 is a schematic diagram showing an example of a manufacturing apparatus for manufacturing a filter structure according to an embodiment of the present invention. Referring to Fig. 2, the manufacturing apparatus P has a supply means for an acrylic hot melt M, a supply means for a sheet-like filter layer S made of a nonwoven fabric or the like, a supply means for a release sheet T made of a PET film or the like, a hot melt supply roll 2 and an auxiliary roll 1 for storing and sending out the acrylic hot melt M, a coating roll 3 and a backup roll 4 for coating one side of the filter layer S with the acrylic hot melt M, nip rolls 5 and 6 for laminating and bonding the filter layer S and the release sheet T, supply rolls 10 and 11 for supplying the release sheet T while adjusting the conveying speed, and conveying rolls 12, 13, and 14 for conveying the release sheet T. The auxiliary roll 1, the hot melt supply roll 2, the coating roll 3, and the backup roll 4 are arranged adjacent to each other and are configured to rotate in conjunction with each other. The molten acrylic hot melt M is stored above the butted portion of the hot melt supply roll 2 and the auxiliary roll 1. When the hot melt supply roll 2 is rotated, the acrylic hot melt M adhering to its surface is transferred to the surface of the coating roll 3 in contact with it. The amount of the acrylic hot melt M transferred can be controlled by adjusting the gap dimension between the hot melt supply roll 2 and the auxiliary roll 1. The coating roll 3 can be a known printing roll such as a gravure roll or letterpress roll.

[0030] By passing the filter layer S between the coating roll 3, which has acrylic hot melt M attached to its surface by the transfer from the hot melt supply roll 2, and the backup roll 4, desired characters, designs, etc. can be printed on one side of the filter layer S with the acrylic hot melt M. The filter layer S with the characters, etc. printed thereon is supplied to the nip rolls 5 and 6. A release sheet T made of PET or the like is transported to the positions of the nip rolls 5 and 6 by the supply rolls 10 and 11 and the transport rolls 12, 13, and 14. The transport speed of the release sheet T is adjusted by the rotation speed of the supply rolls 10 and 11, and is controlled to match the transport speed of the filter layer S. The filter layer S and the release sheet T supplied to the nip rolls 5 and 6 are passed between the nip rolls 5 and 6 with the surface of the filter layer S coated with the acrylic hot melt M facing the release sheet T. This allows a filter structure F in which the filter layer S and the release sheet T are laminated and bonded together to be obtained.

[0031] The long filter structure F thus manufactured is then cut to a predetermined size as necessary and commercialized for sale as a filter product with a release sheet. When using the filter product, the release sheet T is peeled off at the work site, and the filter layer S made of nonwoven fabric or the like is attached to an object using the adhesive layer N.

[0032] Fig. 3 is a schematic diagram showing another embodiment of a manufacturing apparatus for manufacturing a filter structure according to an embodiment of the present invention. Referring to Fig. 3, the manufacturing apparatus Q includes a filter layer S supplying means, a release sheet T supplying means, an acrylic hot melt M supplying means, a coating means for coating the acrylic hot melt M on the release sheet T, and a pressing means for pressing the filter layer S against the adhesive layer, as well as a hardness adjusting means for adjusting the hardness of the adhesive layer so that only a part of the adhesive layer penetrates into the gaps in the filter layer S. The filter layer S is, for example, a nonwoven fabric, and the release sheet T is, for example, a PET film. The filter layer S supplying means includes supply rolls 10 and 11 for supplying the filter layer S while adjusting the conveying speed, and conveying rolls 12, 13, and 14 for conveying the filter layer S. The acrylic hot melt M supplying means includes a hot melt supply roll 2 and an auxiliary roll 1 for storing and sending out the acrylic hot melt M. The coating means includes a coating roll 3 and a backup roll 4 for coating the acrylic hot melt M supplied from the hot melt supply roll 2 to form a pressure-sensitive adhesive layer N of a predetermined pattern. The pressing means includes nip rolls 5 and 6 for laminating the filter layer S on the release sheet T and pressing them together. The hardness adjusting means includes a metal roll 7 that contacts the surface of the release sheet T opposite to the surface on which the pressure-sensitive adhesive layer N is formed. Note that a known mechanism can be used for the release sheet T supplying means, and illustrations are omitted. The auxiliary roll 1, the hot melt supply roll 2, the coating roll 3, and the backup roll 4 are arranged adjacent to each other and are configured to rotate in conjunction with each other.

[0033] The acrylic hot melt M in a molten state is stored at the top of the butted portion between the hot melt supply roll 2 and the auxiliary roll 1. When the hot melt supply roll 2 is rotated, the acrylic hot melt M attached to its surface is transferred to the surface of the coating roll 3 in contact with it. The amount of the acrylic hot melt M transferred can be controlled by adjusting the gap dimension between the hot melt supply roll 2 and the auxiliary roll 1. The coating roll 3 can be a known printing roll such as a gravure roll or a letterpress roll. In addition, the surface of the coating roll 3 is made a metal surface to improve the releasability, and the transfer of the acrylic hot melt M from the coating roll 3 to the release sheet T is made smooth. When the release sheet T is passed between the coating roll 3 on whose surface the acrylic hot melt M transferred from the hot melt supply roll 2 is attached and the backup roll 4, the acrylic hot melt M is applied to one side of the release sheet T, and an adhesive layer N can be formed. The adhesive layer N can also be in the form of letters, designs, etc. The metal roll 7, which is brought into contact with the surface of the release sheet T opposite to the surface on which the adhesive layer N is formed, is made of a metal with high thermal conductivity such as copper, brass, aluminum, iron, or stainless steel. The heat capacity can be set by appropriately selecting the material and the outer dimensions. The contact area between the metal roll 7 and the release sheet T can be set by the diameter of the metal roll 7, the position of the metal roll 7 relative to the path of the release sheet T, and the like. The metal roll 7 may be provided with an appropriate heat dissipation mechanism or cooling mechanism. The metal roll 7 can also have a function of a tensor that applies tension to the release sheet.

[0034] Next, a method for manufacturing the filter structure F using the manufacturing device Q will be described. With reference to FIG. 3, by rotating the hot melt supply roll 2, the molten acrylic hot melt M stored at the upper part of the butted portion between the hot melt supply roll 2 and the auxiliary roll 1 is transferred to the surface of the coating roll 3 in contact with the hot melt supply roll 2. Then, by passing the release sheet T supplied from the supply means between the coating roll 3 and the backup roll 4, the acrylic hot melt M is coated in a predetermined pattern on one side of the release sheet T, and a pressure-sensitive adhesive layer N in a predetermined pattern is formed on the release sheet T. Next, the release sheet T on which the pressure-sensitive adhesive layer N has been formed is transported to the position of the metal roll 7, and the surface on the side on which the pressure-sensitive adhesive layer N has not been formed is engaged with the metal roll 7. The metal roll 7 is configured to have a temperature lower than that of the pressure-sensitive adhesive layer N, excellent thermal conductivity, and sufficient heat capacity. Therefore, the adhesive layer N in a softened state on the release sheet T is cooled by the metal roll 7 through the release sheet T, so that the region of the adhesive layer N near the release sheet T becomes a hardness-increased region in which the hardness is increased by the temperature drop. In contrast, the surface side region of the adhesive layer N away from the release sheet T is maintained in a softened state region having fluidity. Since the contact between the release sheet T and the metal roll 7 is almost uniform in every part, the temperature drop of the adhesive layer N caused by this contact is almost uniform, and the adhesive layer N is in a state in which the hardness changes continuously from the region near the release sheet T to the surface side region, and this change state is almost uniform along the longitudinal direction of the adhesive layer N. The hardness change state of the adhesive layer N can be easily controlled by adjusting the temperature, thermal conductivity, heat capacity, contact area and contact time with the release sheet T, etc. of the metal roll 7. Therefore, by controlling the hardness change state, it is possible to adjust the proportion of the pressure-sensitive adhesive layer N penetrating into the filter layer S and the thickness of the filter layer S located on the surface side in the process described below.

[0035] In this way, the release sheet T with the hardness of the pressure-sensitive adhesive layer N adjusted is transported to the positions of the nip rolls 5 and 6. On the other hand, the filter layer S is also transported to the positions of the nip rolls 5 and 6 by the supply rolls 10 and 11 and the transport rolls 12, 13 and 14. At this time, the transport speeds of the filter layer S and the release sheet T are controlled so as to match at the positions of the nip rolls 5 and 6. The filter layer S and the release sheet T supplied to the nip rolls 5 and 6 are passed between the nip rolls 5 and 6 with the filter layer S facing the surface of the release sheet T on which the pressure-sensitive adhesive layer N is formed. As a result, the pressure-sensitive adhesive layer N on the release sheet T is pressed against the filter layer S, and a filter structure F in which the two are integrated is produced.

[0036] In the filter structure F of this embodiment, the pressure-sensitive adhesive layer N may not be formed on the entire surface of the filter layer S, and the acrylic hot melt M may be partially coated by pattern coating. The preferred coating amount of the acrylic hot melt M is 20 to 50 g / m 2 , more preferably 25 to 35 g / m 2 The preferred application rate of the pressure-sensitive adhesive layer N to the filter layer S is in the range of 5 to 95%, more preferably in the range of 30 to 90%, and even more preferably in the range of 40 to 80%. By setting the application amount and application rate within the above ranges, it is possible to ensure the reliability of attachment to the target part. However, the above values ​​can be changed as appropriate depending on the application and size of the filter structure F.

[0037] The filter structure of the present invention can be widely used as an air filter product in, for example, kitchen and kitchen range hoods, air conditioners, ventilation fans, and other household appliances, indoor and outdoor vents, and also in ventilation locations in industrial appliances. In this case, as shown in FIG. 1, the adhesive layer N formed of acrylic hot melt M may display the letter L or the like indicating the time to replace the filter. As a result of the filter layer S being colored by capturing dust in the air in the parts other than the letter L, the colorless letter L, which was barely discernible before the start of use, becomes a white letter as the surrounding area becomes colored over the course of use, and can be clearly read. Therefore, by setting the content displayed by the letter L to indicate the time to replace the filter, the time to replace the filter can be displayed to the user.

[0038] In addition, an electrostatic filter having the function of effectively removing ultrafine particles by electrostatic force can be used for the filter layer. For example, electrostatic filters include polypropylene nonwoven fabrics that have been subjected to corona discharge treatment or the like and then charged during the tanning process after resin-processing nonwoven fabrics containing wool fibers, and core-sheath composite fibers in which the surface of polypropylene resin is covered with polyethylene resin, and the fiber surface is polarized and charged by generating a high DC electric field using an applied electrode. By using an electrostatic filter for the filter layer, it is possible to remove ultrafine particles called PM2.5, which have a particle diameter of 2.5 μm or less.

[0039] Furthermore, when the filter layer is an electrostatic filter, the decrease in PM2.5 collection efficiency that occurred when a solvent-based adhesive was used in the adhesive layer in the past can be suppressed when an acrylic hot melt is used, so the present invention has the advantage of being able to provide a filter structure with excellent PM2.5 collection effect.

[0040] The filter structure of the present invention can be applied to an object having a surface plated with an aluminum-zinc alloy or a coating such as polyester coating. In particular, most commonly used range hoods are made of a steel plate having a surface plated with various platings or a polyester coating, but the filter structure of the present invention can be applied to an object having a surface plated or coated with the above-mentioned coating to further suppress the occurrence of adhesive residue when removed.

[0041] The filter structure of the present invention can be applied to a relatively large product in which at least one of the filter layers has a length of, for example, 25 cm or more. The larger the filter structure, such as at least one of the filter layers having a length of 30 cm or more, or even 35 cm or more, the more likely it is that the filter structure will fall off or partially peel off from the target object due to its own weight. In particular, when used in a range hood, air conditioner, air purifier, etc., the size of the filter structure used varies depending on the model, but at least one of the lengths is generally large, being several tens of cm or more. Therefore, if the present invention is applied to such a large filter structure, the advantage that the filter structure will not fall off from the target object when attached to the target object under both temperature conditions of 25°C and 5°C becomes clearer. EXAMPLES

[0042] Tests have demonstrated that the filter structure of the present invention can be properly attached to an object without falling off under both temperature conditions of 25°C and 5°C, and that it does not leave any adhesive residue even when peeled off from the object after being attached for a long period of time.

[0043] The sample was made for a metal filter of a range hood, and a filter structure was used in which a hot melt adhesive layer was formed on one side of a filter layer made of nonwoven fabric. The range hood used in the test was a model "BDR-3HL-601BK" manufactured by Fuji Kogyo.

[0044] The tests were conducted on four types of items: 1) maximum peel load at 25°C and 5°C, 2) the attachment of the filter structure to the metal filter, 3) whether or not the filter structure fell off from the metal filter, and 4) whether or not any glue remained on the metal filter.

[0045] 1) Maximum peel load at 25℃ and 5℃ The basic measurement method for the "maximum peel load" was in accordance with "JIS Z 0237:2009", but the measurement conditions were as described below. The test was performed under two temperature conditions of 25°C and 5°C. The "maximum peel load" was measured by measuring the maximum load when peeling the sample from the target object after it was attached to the target object. A constant-speed extension tester was used as the test machine, and filter structures with a width of 5 mm and a length of 250 mm and a width of 10 mm and a length of 250 mm (with similar dimensions for the adhesive layer) were prepared as samples. A stainless steel plate of SUS304 was used as the target surface to be attached. The test was performed by attaching the sample to the target surface, rolling the surface back and forth twice with a 1 kg roller, and then measuring the maximum load when peeling in a 180-degree direction at a peel speed of 100 mm / min.

[0046] 2) Ease of attachment of filter structure to metal filter The metal filter was removed from the range hood and placed on a horizontal stand. A filter structure of the same dimensions as the metal filter was prepared, and the filter structure was attached by pasting the surface on which the adhesive layer was formed on the surface of the metal filter. Note that, when attaching, the filter structure of the specified dimensions was placed on the surface of the metal filter, and the surface of the filter structure on which the adhesive layer was not formed was pressed with a roller at a pressure of 2 kg / cm. 2The metal filter was pressed against the filter structure by one round trip at a pressure of 10 ...

[0047] 3) Whether the filter structure has fallen off from the metal filter The metal filter with the filter structure attached was attached to the range hood in the manner described in the above test "2) Attachability of the filter structure to the metal filter", and the presence or absence of the filter structure falling off from the metal filter after 10 minutes was evaluated by visual observation. That is, the case where no falling off of the filter structure was observed from the metal filter was evaluated as "○", the case where a part of the filter structure was peeled off from the metal filter but the filter structure did not fall off was evaluated as "△", and the case where the filter structure fell off from the metal filter was evaluated as "×". The test was performed under two temperature conditions of 25°C and 5°C.

[0048] 4) Is there any glue residue left on the metal filter? In the test at 25°C in "3) Presence or absence of detachment of the filter structure from the metal filter" described above, the filter structure was peeled off from the metal filter after maintaining the attached state for one month in a temperature environment of 25°C, and then the presence or absence of adhesive residue on the metal filter surface was evaluated by visual observation. That is, the case where there was absolutely no adhesive residue on the metal filter surface was evaluated as "○", and the case where adhesive residue was observed even partially on the metal filter surface was evaluated as "×".

[0049] The test results are shown in Table 1 below.

[0050] [Table 1] The results in Table 1 show that the filter structure of Example 1-3, in which the adhesive layer is formed from an acrylic hot melt adhesive and the ratio K1 / K2 [= maximum peel load N / mm (25°C) ÷ maximum peel load N / mm (5°C)] of the maximum peel load K1 at 25°C to the maximum peel load K2 at 5°C is within the range of 1 to 6, has excellent attachment properties to the metal filter under both temperature conditions of 25°C and 5°C, and there is no falling off of the filter structure from the metal filter or any adhesive residue on the metal filter.

[0051] In contrast, the filter structure according to Comparative Example 1, in which the adhesive layer is formed from an acrylic hot melt adhesive and the ratio K1 / K2 [=maximum peel load N / mm (25°C) ÷ maximum peel load N / mm (5°C)] of the maximum peel load K1 at 25°C to the maximum peel load K2 at 5°C is outside the range of 1 to 6, is poorly attached to the metal filter and falls off from the metal filter at a temperature condition of 5°C. Similarly, the filter structure according to Comparative Example 2 has no problems with attachment to the metal filter and with the filter structure falling off from the metal filter, but not only does K1 / K2 fall outside the range of 1 to 6, but the maximum peel load K1 at 25°C is significantly greater than 0.18 N / mm, so that adhesive residue is left on the metal filter. [Explanation of symbols]

[0052] F…Filter structure P…Manufacturing equipment Q…Manufacturing equipment M: Acrylic hot melt N…Adhesive layer L…letter S: Filter layer T…Release sheet 1...Auxiliary roll 2…Hot melt supply roll 3…Coating roll 4...Backup role 5, 6...Nip roll 7…Metal roll 10, 11…Supply roll 12, 13, 14...Transport roll In addition, the same symbols in each drawing indicate the same or corresponding parts.

Claims

1. A filter structure for attaching to an object to filter gas passing therethrough, A filter layer made of a breathable sheet-like member; An adhesive layer for attaching the filter to an object is formed on at least a part of one surface of the filter layer, The pressure-sensitive adhesive layer is formed of an acrylic hot-melt pressure-sensitive adhesive, and has a maximum peel load K at 25° C. when attached to the object. １ and maximum peel load K at 5°C ２ Relative to K １ / K ２ is within the range of 1 to 6, and does not fall off from the object when attached to the object under temperature conditions of 25° C. and 5° C., The pressure-sensitive adhesive layer has a maximum peel load K １ is in the range of 0.01 to 0.18 N / mm, and the maximum peel load K at 5° C. ２ is in the range of 0.01 to 0.05 N / mm, The filter structure does not leave any adhesive residue even when peeled off from an object after maintaining the attached state for one month under a temperature condition of 25°C.

2. A filter structure for attaching to an object to filter gas passing therethrough, A filter layer made of a breathable sheet-like member; and an adhesive layer formed on at least a portion of one surface of the filter layer for attachment to an object, The pressure-sensitive adhesive layer is formed of an acrylic hot-melt pressure-sensitive adhesive, and has a maximum peel load K at 25° C. when attached to the object. １ and maximum peel load K at 5°C ２ Relative to K １ / K ２ is within the range of 1 to 6, and does not fall off from the object when attached to the object under temperature conditions of 25° C. and 5° C., The pressure-sensitive adhesive layer has a maximum peel load K １ is in the range of 0.01 to 0.18 N / mm, and the maximum peel load K at 5° C. ２ is in the range of 0.01 to 0.05 N / mm, The filter structure has a length of at least one of the filter layers of 25 cm or more, and leaves no adhesive residue when peeled off from the object after maintaining the attached state for one month under a temperature condition of 25°C.

3. 3. The filter structure according to claim 1, wherein the surface of the object is plated with metal or painted with resin.

4. The filter structure according to any one of claims 1 to 3, wherein a coating rate of the adhesive forming the adhesive layer on one surface of the filter layer is 5 to 95%.

5. 5. A filter structure according to claim 1, wherein at least one of the filter layers has a length of 25 cm or more.

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