filter structure

Abstract

The present invention provides a filter structure that does not deteriorate the condition of the adhesive surface of the adhesive layer and allows the adhesive layer to exhibit appropriate adhesive strength. [Solution] A filter structure F having a filter layer 1, an adhesive layer 10, and a sheet layer 20, wherein the sheet layer has a thickness of 12 μm to 75 μm and a surface roughness Ra of 0.09 μm to 0.4 μm on the surface in contact with the adhesive layer. By making the sheet layer thickness 12 μm or more, waviness when laminated on the adhesive layer is suppressed and the surface smoothness of the adhesive layer is maintained. By making the sheet layer thickness 75 μm or less, the sheet layer is less likely to separate from the adhesive layer when folded. By making the surface roughness Ra of the sheet layer 0.4 μm or less, the surface roughness of the adhesive layer in contact with it is controlled to ensure that adhesive force is reliably exerted. By making the surface roughness of the sheet layer 0.09 μm or more, handling is improved and manufacturing costs are not increased.

Description

Technical Field

[0001] The present invention relates to a filter structure that is attached to objects such as range hoods, air conditioners, air purifiers, vents, etc. to filter the passing gas.

Background Art

[0002] Filter structures for filtering the passing air by attaching them to the metal filters or rectifier plates of range hoods, the air inlets of air conditioners and air purifiers, the indoor and outdoor vents, etc. have been conventionally used. For example, Patent Document 1 describes a filter structure mainly used for air conditioners, and Patent Document 2 describes a filter structure used for a range hood with a rectifier plate.

[0003] Filter structures such as those described in these documents generally have a structure including a sheet-like filter layer made of a non-woven fabric or the like, an adhesive layer formed by an adhesive on one surface of the filter layer, and a sheet layer laminated peelably on the surface of the adhesive layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] FIG. 3 is a cross-sectional view showing a state in which the sheet layer undulates in a conventional filter structure, and FIG. 4 is a cross-sectional view showing a state in which the sheet layer separates from the adhesive layer when folded in a conventional filter structure.

[0006] To attach a filter structure like the one described in Patent Document 1 or Patent Document 2 to an object such as a range hood or air intake vent, the sheet layer laminated on the surface of the adhesive layer is peeled off to expose the surface of the adhesive layer, the entire filter structure is kept unfolded and aligned with the attachment location on the object, and then the adhesive layer is attached to the object.

[0007] Incidentally, deterioration of the surface condition of the adhesive layer in the filter structure can prevent the desired adhesive strength from being achieved, which can lead to problems such as difficulty in attaching the filter structure to the object or the filter structure easily falling off the object.

[0008] Referring to Figure 3, in a filter structure 30 having a laminated structure of a filter layer 31, an adhesive layer 32, and a sheet layer 33, if, for example, an adhesive layer 32 is formed on the filter layer 31 by first applying adhesive to the sheet layer 33 and then overlapping the adhesive-coated surface of the sheet layer 33 with the filter layer 31 to transfer the adhesive from the sheet layer 33 to the filter layer 31 and then solidifying the adhesive by drying or other means as appropriate, when the thickness of the sheet layer 33 is thin, the sheet layer 33 may become wavy after the adhesive is applied to the sheet layer 33 or after the adhesive is transferred from the sheet layer 33 to the filter layer 31. The reason why the sheet layer 33 becomes wavy is not clear, but it is presumed that if the sheet layer 33 is thin when an adhesive containing a solvent is used as the adhesive, the sheet layer 33 swells due to the solvent contained in the adhesive, resulting in a wavy state, or that the sheet layer 33 shrinks or deforms due to heat when drying is performed to evaporate the solvent contained in the adhesive after the adhesive has been transferred from the sheet layer 33 to the filter layer 31. As a result of the wavy state of the sheet layer 33, the adhesive layer 32 formed on the filter layer 31 also becomes wavy, reducing the smoothness of the adhesive surface 32a. Consequently, the contact area of ​​the adhesive layer 32 with the object decreases, making it difficult to exert appropriate adhesive strength.

[0009] Referring to Figure 4, the filter structure 30 is often shipped folded and packaged. However, if the thickness of the sheet layer 33 is too large, the bending strength of the sheet layer 33 becomes too strong, which can cause the sheet layer 33 to separate from the surface of the adhesive layer 32 when the filter structure 30 is folded. In the filter structure 30, the areas 32b where the sheet layer 33 has separated and the adhesive layer 32 is exposed are prone to accumulating fiber debris and other materials before use. As a result, the condition of the adhesive surface deteriorates, making it difficult to exert appropriate adhesive force to the object when used.

[0010] Furthermore, if a sheet layer 33 with a high surface roughness is used, the surface roughness of the adhesive layer 32 in contact with it will also increase in proportion to the surface roughness of the sheet layer 33, which may result in a decrease in the adhesive strength of the adhesive layer 32 to the object.

[0011] Furthermore, while it is preferable for the surface roughness of the sheet layer 33 to be relatively small, if the surface roughness is too small, that is, if the surface smoothness is very high, it becomes difficult to handle the sheet layer 33 during the manufacturing of the filter structure, and the manufacturing cost also increases.

[0012] In view of the above-mentioned conventional problems, the present invention aims to provide a filter structure that does not worsen the condition of the adhesive surface of the adhesive layer and allows the adhesive layer to exhibit appropriate adhesive strength. [Means for solving the problem]

[0013] To achieve the above objective, the invention described in claim 1 is a filter structure having a filter layer that is permeable and filters the gas passing through it, an adhesive layer formed of an adhesive on at least a part of one side of the filter layer, and a sheet layer laminated on the surface of the adhesive layer and peelable, wherein the sheet layer has a thickness of 12 μm to 75 μm and the arithmetic mean roughness Ra (arithmetic mean roughness Ra according to JIS B0601:2001) of the surface in contact with the adhesive layer is 0.09 μm to 0.4 μm.

[0014] In this configuration, the sheet layer covers and protects the surface of the adhesive layer. When the sheet layer is peeled off, the adhesive layer is exposed, and the filter structure becomes usable. Since the thickness of the sheet layer is 12 μm or more, the sheet layer is less likely to warp when laminated on the surface of the adhesive layer. Since the thickness of the sheet layer is 75 μm or less, the sheet layer can easily follow deformations such as bending and folding of the filter structure. Since the surface roughness Ra of the surface of the sheet layer that is in contact with the adhesive layer is set to 0.09 μm or more and 0.4 μm or less, the surface roughness of the adhesive layer in contact with it can be controlled.

[0015] The invention described in claim 2 is the configuration of the invention described in claim 1, wherein the arithmetic mean roughness Ra of the surface of the sheet layer is 0.1 μm to 0.25 μm.

[0016] With this configuration, the surface roughness Ra of the sheet layer is in the range of 0.1 μm to 0.25 μm, which results in high surface smoothness of the adhesive layer after the sheet layer has been peeled off.

[0017] The invention described in claim 3 is the configuration of the invention described in claim 1 or claim 2, wherein the thickness of the sheet layer is 12 μm to 25 μm.

[0018] With this configuration, the sheet layer thickness is in the range of 12 μm to 25 μm, which makes it easier for the sheet layer to follow deformations such as bending and folding of the filter structure.

[0019] The invention according to claim 4 is used in at least one of the metal filter or rectifying plate of a range hood, the air intake of an air conditioner, the air intake of an air cleaner, and the indoor and outdoor ventilation openings in the configuration of the invention according to any one of claims 1 to 3.

[0020] With such a configuration, the filter structure is used in at least one of the metal filter or rectifying plate of a range hood, the air intake of an air conditioner, the air intake of an air cleaner, and the indoor and outdoor ventilation openings to filter the passing gas.

Advantages of the Invention

[0021] As described above, according to the invention of claim 1, since the surface of the adhesive layer is protected by the sheet layer, it is possible to prevent the adhesive layer from sticking to other than the target object before the use of the filter structure. Also, it becomes possible to stack a plurality of filter structures, etc., improving the handling property. By setting the thickness of the sheet layer to 12 μm or more, the undulation of the sheet layer is suppressed, and as a result, the smoothness of the surface of the adhesive layer is maintained, so that an appropriate adhesive force is exhibited when attaching to the object. By setting the thickness of the sheet layer to 75 μm or less, the sheet layer can follow the deformation such as bending or folding of the filter structure, so that even when the filter structure is bent or folded, the sheet layer is difficult to separate from the adhesive layer. As a result, it becomes difficult to expose the adhesive layer before the use of the filter structure, and it is possible to suppress the decrease in the adhesive force due to the adhesion of fiber debris, etc. during use. Also, since the surface roughness Ra of the sheet layer is 0.09 μm or more and 0.4 μm or less, the surface roughness of the adhesive layer in contact with this can be controlled to ensure that the adhesive force is exerted.

[0022] According to the invention of claim 2, in addition to the effect of the invention of claim 1, since the smoothness of the surface of the adhesive layer after the peeling of the sheet layer is increased, it is possible to exhibit an excellent adhesive force to the object.

[0023] According to the invention described in claim 3, in addition to the effects of the invention described in claim 1 or claim 2, since the sheet layer can more easily follow deformations such as bending and folding of the filter structure, the sheet layer does not separate from the surface of the adhesive layer even when the filter structure is bent or folded. Therefore, even in a bent state or a folded state, the sheet layer surely protects the surface of the adhesive, and suppresses a decrease in the adhesive force due to adhesion of fiber dust or the like. As a result, since the filter structure can be packaged in a folded state, a product with good handling properties can be provided.

[0024] According to the invention described in claim 4, in addition to the effects of the invention described in any one of claims 1 to 3, since the adhesive layer exhibits excellent adhesive force, it can be surely attached to any object to be used, and there is no risk of falling off over a long period of time.

Brief Description of Drawings

[0025] [Figure 1] It is a front view showing an example of a filter structure according to an embodiment of the present invention. [Figure 2] It is a perspective view showing a state in which a region S surrounded by a dashed line in the filter structure shown in FIG. 1 is enlarged and a part of the sheet layer is peeled off. [Figure 3] It is a cross-sectional view showing a state in which a problem of the sheet layer undulating occurs in a conventional filter structure. [Figure 4] It is a cross-sectional view showing a state in which a problem of the sheet layer separating from the adhesive layer when folded occurs in a conventional filter structure.

Embodiments for Carrying Out the Invention

[0026] FIG. 1 is a front view showing an example of a filter structure according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a state in which a region S surrounded by a dashed line in the filter structure shown in FIG. 1 is enlarged and a part of the sheet layer is peeled off.

[0027] This filter structure F is for adhering to an object and filtering gas passing through it, and comprises a sheet-like filter layer 1 that is permeable and filters the gas passing through it, an adhesive layer 10 formed by an adhesive on at least a part of one side of the filter layer 1 and exhibiting adhesive force to the object, and a sheet layer 20 laminated on the surface of the adhesive layer 10 and peelable.

[0028] (Filter layer) The filter layer 1 is composed of, for example, a nonwoven fabric, woven fabric, or knitted fabric, and is designed to achieve both dust collection and gas flow while possessing practical strength. Preferably, nonwoven fabrics composed of synthetic resin fibers such as polyethylene terephthalate (PET) or other polyester, polypropylene or propylene-based copolymers, or acrylic containing modacrylic can be used, but are not limited to these. There are no limitations on the manufacturing method of the nonwoven fabric, and nonwoven fabrics manufactured by known methods such as chemical bonding or thermal bonding can be suitably used. Furthermore, the filter layer 1 may be treated with antiviral or antibacterial processing. In addition, for the purpose of imparting flame retardancy, an appropriate amount of fatty acid metal salts such as aluminum stearate may be attached to the above-mentioned synthetic resin fibers, or flame-retardant fibers may be mixed in. The thickness of the filter layer 1 is 0.3 to 15.0 mm, and the basis weight is 20 to 200 g / m². 2 It is preferable to keep the thickness within this range. With this configuration, it is possible to reliably capture oil mist and dust from the air while allowing gas to pass through, and it also has practical strength. Thickness of less than 0.3 mm, or basis weight of 20 to 200 g / m 2 If the thickness is less than 15.0 mm, the material may lack sufficient practical strength and may not perform adequately in terms of filtration. 2 If this value is exceeded, the resistance to gas flow will increase, potentially impairing its practicality as an air filter.

[0029] (Adhesive layer) The adhesive forming the adhesive layer 10 is not particularly limited, and for example, a two-component mixed adhesive containing a main component and a curing agent, such as a two-component polyurethane-based adhesive, or a hot-melt adhesive, such as an acrylic-based hot-melt adhesive, can be used. In addition, the adhesive may contain, as needed, tackifiers to improve adhesion, additives such as UV absorbers, fillers, colorants, antioxidants, defoamers, and light stabilizers, as well as various additives to suppress the decrease in adhesive strength at low temperatures and adhesive residue.

[0030] A known method can be used to form the adhesive layer on the filter layer. For example, the adhesive can be applied directly to the nonwoven fabric, or the adhesive can be applied indirectly by first applying it to a peelable sheet layer, such as one described later, and then bringing the sheet layer into contact with the nonwoven fabric to transfer the adhesive to the nonwoven fabric, thereby forming the adhesive layer, which is then solidified by drying or cooling. The method of applying the adhesive layer to the filter layer, directly or indirectly, is not limited, but can be carried out by means of rollers, sprays, brushes, printing, etc. That is, any known method can be used, such as the roll coater method, comma coater method, die coater method, inkjet method, reverse coater method, silkscreen method, gravure coater method, etc. When applying indirectly, for example, the adhesive can be printed onto a peelable release sheet layer coated with silicone using a roll, and then the adhesive layer side of this sheet layer can be brought into contact with the filter layer and pressed with a roll to transfer the adhesive layer to the filter layer.

[0031] Furthermore, the filter structure F in this example is for range hoods, and the adhesive layer 10 is formed in a shape that can accommodate range hoods of different sizes. Specifically, the filter layer 1 has a rectangular shape with the short side 1a direction being vertical and the long side 1b direction being horizontal, and three perforations 11a to 11c are formed parallel to the short side 1a and spaced approximately equally apart, penetrating the filter layer and the sheet layer. The adhesive layer 10 has four regions partitioned by the perforations 11a to 11c, each of which has a first frame section 12a to a fourth frame section 12d formed in the shape of an approximately rectangular frame. In addition, grid sections 13a to 13d are formed inside each of the first frame section 12a to the fourth frame section 12d, which are inclined at approximately 45° with respect to the short side 1a and the long side 1b. Furthermore, a display section 14 in the form of characters or the like indicating when the filter needs to be replaced is formed in the portion where parts of the first frame section 12a to the fourth frame section 12d and the grid sections 13a to 13d have been omitted.

[0032] Since the adhesive layer 10 is configured in this way, the filter structure F can be made to the desired size by cutting the filter layer and sheet layer at perforations 11a to 11c selected according to the size of the range hood to be attached. Furthermore, in this example, since the first frame portion 12a to the fourth frame portion 12d are formed in each region demarcated by the perforations 11a to 11c, the filter structure F after cutting will have the adhesive layer 10 along its contour, so it can be reliably attached to the object, and it is possible to eliminate the gap between the filter layer 1 and the surface of the object over almost the entire circumference of the filter layer 1.

[0033] The grid sections 13a to 13d contribute to the adhesive force of the filter structure F. In particular, when used in a range hood with a baffle plate, the grid sections 13a to 13d adhere to the baffle plate, thereby improving the adhesive force of the filter structure F in addition to the adhesive force of the first frame sections 12a to the fourth frame sections 12d. Furthermore, by forming the adhesive in a grid pattern, the area that blocks the air intake of the range hood, etc., can be reduced, making it less likely to obstruct airflow.

[0034] Furthermore, the display unit 14 is for visually indicating when the filter structure F needs to be replaced, and may be formed in the form of pictures or figures in addition to the illustrated character form. In the parts of the filter layer 1 where air flows, discoloration progresses due to the accumulation of dust, etc., whereas in the parts where the adhesive layer is formed, air flow is suppressed, so the filter layer 1 does not discolor. As a result, as use continues, the characters etc. of the display unit 14 formed with adhesive will stand out in white, making it possible to indicate when the filter structure F needs to be replaced. The display unit 14 also contributes to the adhesive strength to the object.

[0035] (Sheet layer) The sheet layer 20 is laminated on the surface of the adhesive layer 10 to protect the adhesive surface 10a. By providing the sheet layer 20, it is possible to prevent the adhesive layer 10 from sticking to objects other than the target object before use of the filter structure F. Furthermore, it becomes possible to stack multiple filter structures, improving handling. When using the filter structure, as shown in Figure 2, the sheet layer 20 is peeled off from the adhesive layer 10, and the exposed adhesive surface 10a is attached to the target object like a sticker.

[0036] The material of the sheet layer 20 is not particularly limited, as long as it can satisfy the thickness and surface roughness conditions described later. For example, a PET film with a silicone coating formed on at least one surface can be used. Cellophane and resin films other than PET can also be used. Furthermore, paper or metal sheets with surface treatments such as resin coatings can also be used, as long as they satisfy the thickness and surface roughness conditions described later.

[0037] The sheet layer in this example preferably has a thickness in the range of 12 μm to 75 μm, and more preferably in the range of 12 μm to 25 μm. Furthermore, the arithmetic mean roughness (Ra) of the surface of the sheet layer (arithmetic mean roughness according to JIS B0601:2001; hereinafter referred to as "surface roughness") preferably has a thickness in the range of 0.09 μm to 0.4 μm, and more preferably in the range of 0.1 μm to 0.25 μm. The thickness of the sheet layer can be measured using the micrometer method (JIS C2151).

[0038] If the sheet layer thickness is 12 μm or more, the waviness of the sheet layer laminated on the surface of the adhesive layer of the filter structure can be suppressed, and as a result, the smoothness of the surface of the adhesive layer is maintained, allowing it to adhere closely to the object and exhibit appropriate adhesive strength. If the sheet layer thickness is less than 12 μm, waviness is more likely to occur, which may result in poor surface smoothness of the adhesive layer.

[0039] Furthermore, if the sheet layer thickness is 75 μm or less, the sheet layer can follow the deformation of the filter structure, such as bending or folding, making it less likely for the sheet layer to separate from the adhesive layer even when the filter structure is bent or folded. As a result, it becomes less likely for the adhesive layer to be exposed before use of the filter structure, and the reduction in adhesive strength due to the adhesion of fiber debris during use can be suppressed. If the sheet layer thickness exceeds 75 μm, the bending strength of the sheet layer becomes too strong, and when the filter structure is folded, there is a risk that the part of the sheet layer corresponding to the bent part of the filter structure will separate from the surface of the adhesive layer. In the filter structure, areas where the sheet layer has separated in this way and the adhesive layer is exposed are more likely to accumulate fiber debris before use, and as a result, the condition of the adhesive surface deteriorates, making it difficult to exert appropriate adhesive strength to the object during use.

[0040] When the surface roughness Ra of the sheet layer is between 0.09 μm and 0.4 μm, the surface roughness of the adhesive layer in contact with it can be controlled to ensure that adhesive strength is reliably exerted, resulting in good adhesion to the object.

[0041] If the surface roughness Ra of the sheet layer exceeds 0.4 μm, the surface roughness of the adhesive layer in contact with it will also increase, reducing the contact area with the object. As a result, the adhesive strength may not be fully realized.

[0042] If the surface roughness of the sheet layer is less than 0.09 μm, the surface smoothness of the sheet layer becomes very high, which makes the sheet layer difficult to handle during the manufacturing of the filter structure. Furthermore, it may increase manufacturing costs.

[0043] Furthermore, it is more preferable that the surface roughness Ra of the sheet layer be in the range of 0.1 to 0.25 μm. Setting the surface roughness Ra within this range increases the smoothness of the adhesive layer surface after peeling off the sheet layer, allowing for superior adhesion to the target object, and in particular, suppressing the decrease in adhesive strength under high-temperature conditions over time.

[0044] Furthermore, the thickness of the sheet layer is more preferably in the range of 12 to 25 μm. By setting the thickness within this range, the sheet layer can more easily follow the deformation of the filter structure, such as bending or folding, and the sheet layer can follow the deformation of the filter layer and adhesive layer even when the filter structure is bent or folded, so the sheet layer is less likely to separate from the surface of the adhesive layer. Therefore, even in bent or folded states, the sheet layer reliably protects the surface of the adhesive layer and suppresses the reduction of adhesive strength on the adhesive surface due to fiber debris, etc. As a result, it is possible to package the filter structure in a folded state, so a product with good handling properties can be provided.

[0045] As described above, the filter structure in this example maintains the smoothness of the surface of the adhesive layer when the sheet layer is peeled off, and possesses good smoothness. This results in high adhesion when pressed against an object, allowing it to exhibit appropriate adhesive strength. Moreover, it does not reduce handling difficulties or cause any significant cost increases compared to conventional products.

[0046] The filter structure in this example can be used on the outside of range hoods in kitchens and food preparation areas, air intakes for air conditioners and air purifiers, ventilation fans and other household or commercial equipment, and ventilation openings installed indoors and outdoors.

[0047] Depending on the form of the application, it may be necessary to cut a portion of the filter structure. For example, when using a filter structure in a front-intake air purifier, the support that holds the front cover of the air purifier may interfere with the filter structure, so the area including the four corners of the rectangular filter layer is designated as the area to be cut. To address this, at least one of the filter layer and the sheet layer may be marked by printing or other means to indicate the area to be cut of the filter layer. Alternatively, perforations may be formed along the area to be cut of the filter layer. Furthermore, the adhesive layer may be formed to indicate the area to be cut of the filter layer. Note that the area to be cut is not limited to the corners; the area to be cut may be any part that interferes with the object to which the filter structure is attached during installation. For example, in the case of a circular filter structure, there are no corners, so the area to be cut may be any part that interferes with the object to which it is attached. Furthermore, it is also possible not to set a designated area to be cut.

[0048] Furthermore, although the filter structure in the above embodiment was rectangular, it is not limited to a rectangular shape, and various shapes such as polygons, circles, and ellipses can be used.

[0049] Furthermore, although a display unit indicating the filter replacement time is provided in the above embodiment, it is not necessary. In addition to characters, the display unit may also consist of pictures, symbols, figures, etc. There may be one character, picture, symbol, figure, etc., or multiple characters, pictures, symbols, figures, etc.

[0050] Furthermore, although the above embodiment includes an adhesive layer in which a strip-shaped adhesive is pattern-printed in a frame-like or grid-like form, the adhesive layer may be formed without a strip-shaped adhesive layer, by distributing a spray-applied adhesive evenly across the entire surface of the filter layer. [Examples]

[0051] Using a sheet layer having the material, thickness, and surface roughness described in Table 1, an adhesive layer was first applied to the sheet layer, and then the adhesive-coated surface of the sheet layer was superimposed with the filter layer to transfer the adhesive from the sheet layer to the filter layer, thereby solidifying the adhesive and forming an adhesive layer on the filter layer. This method prepared filter structures for Examples 1 to 8 and Comparative Examples 1 to 11, each comprising a sheet-like filter layer, an adhesive layer 10 formed on a portion of one side of the filter layer, and a peelable sheet layer 20 laminated on the surface of the adhesive layer 10. The filter layer used in the filter structures of the Examples and Comparative Examples was mainly composed of a nonwoven fabric made of PET fibers, with a basis weight of 40 g / m². 2 The amount of adhesive layer applied to the filter structures of the examples and comparative examples was 30 g / m². 2 These were the results. The following tests were conducted using these filter structures.

[0052] (1) Presence or absence of waves For the filter structures of the examples and comparative examples using each of the sheet layers described in Table 1, with the adhesive layer formed on one side of the filter layer and laminated on the surface, the presence or absence of warping of the sheet layer was determined according to the following evaluation criteria. • ○ (or ◎): No waves. • △ (or ○): Slight undulation. • ×…There is clearly significant waviness and looseness in the sheet layer.

[0053] (2) Adhesion suitability (uneven surface) The sheet layer was peeled off to expose the adhesive layer. The filter structures from the examples and comparative examples, cut to 4cm x 11cm, were then attached to this exposed adhesive layer. The board was then propped up vertically, and any detachment was checked. The attachment was done using a roller at a pressure of 2kg / cm². 2 The procedure was carried out using a method involving one round trip. The obtained samples were examined for filter detachment. The following evaluation criteria were used for evaluation. • ○…to stick. ×...It peels off. This test evaluates adhesion to surfaces with some degree of unevenness.

[0054] (3) Adhesion is appropriate (range hood) The adhesive layer, exposed after peeling off the sheet layer, was then applied to a metal filter of a range hood with a fluorine coating on its surface. Each filter structure in the examples and comparative examples, cut to approximately the same dimensions as the metal filter, was then subjected to a roller pressure of 2 kg / cm². 2 After attaching the filter structure using a method involving one pass-through, the filter structure was left undisturbed at room temperature for one week with the attached side facing downwards. The test was conducted to observe whether the filter structure remained attached or peeled off. The following evaluation criteria were used for evaluation. • It's stuck. ×...It peels off.

[0055] (4) Adequate adhesion over time (under high humidity conditions) Half of the sheet layer of the filter structure was peeled off and exposed, then attached to an acrylic plate. This was left undisturbed in an environment of 25°C and 95% humidity. After 24 hours, the acrylic plate was shaken up and down 10 times, and it was observed whether the filter structure remained attached or peeled off. This test evaluates whether or not the adhesive has deteriorated. The following evaluation criteria were used for the determination. • ◎...It won't peel off. • ○…It peels off slightly. • ×…More than half peeled off.

[0056] (5) Suitability for bending processes Each filter structure from the examples and comparative examples was cut to 61 cm x 36 cm, folded in half, and then unfolded back to its original state before folding. The test observed whether the sheet layer lifted away from the adhesive layer at the folded portion. This test evaluates the conformability of the sheet layer. • ◎...When folded and then unfolded again, there is absolutely no lifting of the sheet layer from the adhesive surface. • 〇…There is slight lifting in some areas. • ×…The sheet layer in the folded part lifts completely.

[0057] (Surface roughness measurement) The surface roughness Ra (arithmetic mean roughness Ra according to JIS B0601:2001) of the sheet layer of each filter structure used in the test was measured using a Mitutoyo Corporation CNC surface shape measuring machine "CS-H5000CNC". The evaluation conditions are as follows. Evaluation conditions: Curve = R_J01 - Location = [1] Standard: JIS B0601:2001 Evaluation curve type: R_J01 Standard length: 0.8 mm Number of segments: 5 λc: 0.8mm λs: 0.0025 mm Filter type: Gaussian Evaluation length: 4.0mm Approach: 0.4mm Trailing: 0.397mm Smooth connection: Off The test results are shown in Table 1.

[0058] [Table 1] As shown in Table 1, the embodiment of the present invention exhibits good results in all of tests (1) to (5) due to the sheet layer thickness being in the range of 12 to 75 μm and the surface roughness Ra being in the range of 0.09 to 0.4 μm.

[0059] In particular, sheet layers with a surface roughness Ra in the range of 0.09 to 0.25 μm (Examples 1, 2, 4-7) exhibited excellent adhesion over time in Test (4) (under high humidity conditions).

[0060] Furthermore, it was found that sheet layers with a thickness in the range of 12 to 25 μm (Examples 1 to 5) exhibited excellent suitability for bending processes.

[0061] In contrast, even if the sheet layer is a PET film, if it is too thin, even if the surface roughness Ra is appropriate, it will ripple and will not be able to exhibit proper adhesive strength. Conversely, if the sheet layer is too thick, even if the surface roughness Ra is appropriate, it will have poor suitability for folding.

[0062] Furthermore, it can be seen that the paper sheet layers used in Comparative Examples 8 to 11, since both their thickness and surface roughness fall within the range of the present invention, cannot exhibit appropriate adhesive strength or foldability. [Explanation of symbols]

[0063] F...Filter structure 1…Filter layer 1a... Short side 1b... Longer side 10…Adhesive layer 10a...Adhesive surface 11a~11c...Perforations 12a~12d...1st frame ~4th frame 13a~13d...Grid section 14...Display section 20…Sheet layer 30…Filter structure 31…Filter layer 32…Adhesive layer 32a…adhesive surface 32b... Exposed areas of the adhesive layer 33…Sheet layer In each figure, the same reference numeral indicates the same or corresponding part.

Claims

1. A filter structure comprising a breathable filter layer that filters passing gas, an adhesive layer formed of an adhesive on at least a portion of one side of the filter layer, and a peelable sheet layer laminated on the surface of the adhesive layer, used in at least one of the following: a metal filter or rectifier plate of a range hood, an air intake of an air conditioner, an air intake of an air purifier, and an indoor or outdoor vent, The aforementioned filter structure is deformed by bending or folding before use. The filter structure comprises a sheet layer having a thickness of 12 μm to 75 μm, and the arithmetic mean roughness Ra (arithmetic mean roughness Ra according to JIS B0601:2001) of the surface of the side in contact with the adhesive layer being 0.09 μm to 0.4 μm.

2. A filter structure comprising: a filter layer that is permeable and filters gas passing through it; an adhesive layer formed of an adhesive on at least a part of one side of the filter layer; and a sheet layer laminated on the surface of the adhesive layer and peelable, The filter structure comprises a sheet layer having a thickness of 12 μm to 75 μm, and the arithmetic mean roughness Ra (arithmetic mean roughness Ra according to JIS B0601:2001) of the surface of the side in contact with the adhesive layer being 0.09 μm to 0.1632 μm.

3. The filter structure according to claim 1, wherein the arithmetic mean roughness Ra of the surface of the sheet layer is 0.1 μm to 0.25 μm.

4. The filter structure according to any one of claims 1 to 3, wherein the thickness of the sheet layer is 12 μm to 25 μm.

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