Method and apparatus for manufacturing a breathable product

Abstract

The present invention performs the following processes: preparing a gas-permeable substrate (S1) having a gap on at least one side; and preparing an adhesive layer (N) formed on a part of one side, and adjusting the hardness of the adhesive layer (N) so that only a part of the adhesive layer (N) intrudes into the gap of the gas-permeable substrate (S1). Since the adhesive layer (N) having the adjusted hardness is pressed against the gas-permeable substrate (S1), the range of the adhesive layer (N) intruding into the gas-permeable substrate (S1) can be adjusted. Thus, a gas-permeable product (F) in which the layer thickness of the part exposed to the surface of the adhesive layer (N) is optimized can be obtained. In addition, by a part of the adhesive layer (N) intruding into the gap of the gas-permeable substrate (S1), both are integrated after curing, the bonding strength is increased, and thus the adhesive residue at the time of peeling from the mounting object can be suppressed.

Description

Technical Field

[0001] This invention relates to a technology for manufacturing breathable products such as filters, and particularly to a method and apparatus for manufacturing breathable products having an adhesive layer on a portion of one side of a breathable substrate. Background Technology

[0002] Traditionally, breathable products such as filters, which prevent dust and other pollutants from entering the room through ventilation openings, have been manufactured using breathable materials such as woven fabrics. Furthermore, to facilitate installation of such filters at ventilation openings, an adhesive layer is sometimes formed on one side of the breathable substrate, which is made of non-woven fabric or similar material.

[0003] Japanese Patent No. 6178291 discloses a method for manufacturing a filter in which an adhesive layer composed of a hot-melt adhesive is provided on one side of a nonwoven fabric as a substrate. The manufacturing method described in Japanese Patent No. 6178291 involves preparing a letterpress roller having a predetermined raised pattern and being driven to rotate, and a pressure roller that abuts against and rotates with the letterpress roller. After applying a hot-melt adhesive to the raised pattern, the nonwoven fabric is passed between the letterpress roller and the pressure roller, thereby transferring the hot-melt adhesive attached to the raised pattern on the letterpress roller onto the nonwoven fabric. Next, a release paper is overlapped to cover the hot-melt adhesive, thereby manufacturing a filter having a hot-melt adhesive layer and a release paper on one side of a substrate.

[0004] According to this manufacturing method, when transferring a hot melt adhesive onto a nonwoven fabric, the nonwoven fabric and the adhesive layer are integrated by infiltrating a portion of the hot melt adhesive into the gaps between the fibers constituting the nonwoven fabric.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 6178291 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] In the manufacturing method of Patent Document 1, when the hot-melt adhesive is transferred onto a substrate made of nonwoven fabric, the amount of the hot-melt adhesive penetrating into the gaps in the nonwoven fabric is not constant. As a result, there is a problem that the thickness of the portion of the adhesive layer exposed to the substrate becomes uneven or inappropriate depending on the location. In the case of a filter that uses the adhesive layer to attach an object to a vent or similar structure, if the thickness of the exposed portion of the adhesive layer is inappropriate, gaps can easily form between it and the object, potentially damaging the trapping performance or making it easy to remove from the object.

[0010] Therefore, the object of the present invention is to provide a method and apparatus for manufacturing a breathable product having an adhesive layer of appropriate thickness that is exposed to the surface of a breathable substrate.

[0011] Technical solutions adopted to solve technical problems

[0012] To achieve the above objectives, the first aspect of the present invention provides a method for manufacturing a breathable product, comprising: a substrate preparation step of preparing a breathable substrate having gaps on at least one side; a hardness adjustment step of preparing an adhesive layer for forming on a portion of one side and adjusting the hardness of the adhesive layer so that only a portion of the adhesive layer penetrates into the gaps of the breathable substrate; and a pressing step of pressing the hardened adhesive layer onto the breathable substrate.

[0013] If configured in this way, by pressing an adhesive layer with adjusted hardness onto the breathable substrate, only a portion of the adhesive layer penetrates into the gaps of the breathable substrate, thus integrating the two.

[0014] The method for manufacturing a breathable product according to the second aspect of the present invention is in the structure of the invention of the first aspect, wherein the hardness adjustment step includes a hardness increasing step, which increases the hardness of a region in the adhesive layer that includes a side opposite to the side pressed by the breathable substrate.

[0015] If constructed in this way, a hardness difference in the thickness direction will be generated in the adhesive layer.

[0016] The method for manufacturing a breathable product according to the third aspect of the present invention is in the structure of the invention of the second aspect, wherein the adhesive layer is composed of a hot melt adhesive, and the hardening process includes a cooling process, which cools a region in the softened adhesive layer.

[0017] If constructed in this way, the hardness of the cooled areas in the adhesive layer increases because the adhesive is a hot melt adhesive.

[0018] The method for manufacturing a breathable product according to the fourth aspect of the present invention is based on the structure of the invention in the third aspect. The cooling process includes the following steps: preparing a release sheet on one side to form an adhesive layer composed of a softened hot melt adhesive, and cooling the side of the release sheet opposite to the side on which the adhesive layer is formed.

[0019] If configured in this way, the hardness of the area of ​​the adhesive layer near the release sheet increases due to the side of the release sheet opposite to the side where the adhesive layer is formed. Since the surface of the adhesive layer is shaped by the release sheet, it is on the same horizontal plane and becomes smooth.

[0020] The method for manufacturing a breathable product according to the fifth aspect of the present invention is based on the structure of the invention in the fourth aspect, wherein the process of cooling the release sheet includes a process of engaging a metal roller with a temperature lower than that of the adhesive layer with the release sheet.

[0021] If configured in this way, by engaging the low-temperature metal roller with the release slab, the temperature of the area near the release slab in the adhesive layer decreases, and the hardness increases.

[0022] The method for manufacturing a breathable product according to the sixth aspect of the present invention is in the structure of the invention in any one of the first to fifth aspects, wherein the breathable substrate is composed of nonwoven fabric.

[0023] If configured in this way, by pressing the adhesive layer onto the breathable substrate, a portion of the adhesive layer penetrates into the gaps between the fibers of the nonwoven fabric that constitutes the breathable substrate. After curing, the breathable substrate and the adhesive layer become integrated.

[0024] The method for manufacturing a breathable product according to the seventh aspect of the present invention is in the structure of any one of the first to sixth aspects of the invention, wherein the breathable product is a filter.

[0025] If configured in this way, a filter product can be manufactured with an adhesive layer of appropriate thickness that exposes the surface of the breathable substrate.

[0026] The method for manufacturing a breathable product according to the eighth aspect of the present invention is in the structure of the invention in any one of the third to fifth aspects, wherein the breathable product is an electrostatic filter.

[0027] If configured in this way, an electrostatic filter with an adhesive layer made of a hot-melt adhesive can be manufactured.

[0028] A manufacturing apparatus for a breathable product according to a ninth aspect of the present invention is used to manufacture a breathable product having an adhesive layer formed on a portion of one side of a breathable substrate, comprising: a substrate supply unit for supplying a breathable substrate having gaps on at least one side; a release sheet supply unit for supplying a release sheet; an adhesive supply unit for supplying an adhesive; an adhesive coating unit for coating the adhesive supplied from the adhesive supply unit onto a portion of one side of the release sheet supplied from the release sheet supply unit to form an adhesive layer; a hardness adjustment unit for adjusting the hardness of the adhesive layer so that only a portion of the adhesive layer formed by the adhesive coating unit penetrates into the gaps of the breathable substrate; and a pressing unit for pressing the breathable substrate supplied from the substrate supply unit onto the hardened adhesive layer.

[0029] If configured in this way, it becomes a manufacturing apparatus capable of producing a breathable product with the following structure: after the hardness of the adhesive layer applied to the release sheet by the adhesive coating unit is adjusted by the hardness adjustment unit, the breathable substrate is pressed onto the adhesive layer by the pressing unit, the adhesive layer and the release sheet are stacked on one side of the breathable substrate, and a portion of the adhesive layer penetrates into the gaps of the breathable substrate to form an integral structure.

[0030] The apparatus for manufacturing a breathable product according to the tenth aspect of the present invention is based on the structure of the invention in the ninth aspect, wherein the adhesive is a hot melt adhesive, and the hardness adjustment unit includes a metal roller that engages with a release sheet on which the adhesive layer is formed and cools the release sheet.

[0031] If configured in this way, it becomes a manufacturing apparatus that includes a metal roller for cooling a release sheet with an adhesive layer formed on it.

[0032] Invention Effects

[0033] As described above, in the method for manufacturing a breathable product according to the first aspect of the present invention, an adhesive layer with adjusted hardness is pressed onto a breathable substrate, thus allowing adjustment of the extent of the adhesive layer penetrating into the breathable substrate. This results in a breathable product with an optimized layer thickness for the portion exposed on the surface of the adhesive layer. Furthermore, by having a portion of the adhesive layer penetrate into the gaps in the breathable substrate, the two become integrated after curing, increasing the bond strength and thus suppressing adhesive residue when peeled from the object being installed.

[0034] In addition to the effects of the invention in the first aspect, the method for manufacturing a breathable product according to the second aspect of the present invention can also control the ratio of the portion of the adhesive layer that penetrates into the breathable substrate to the portion that is exposed on the surface of the breathable substrate by adjusting the hardness difference in the thickness direction of the adhesive layer.

[0035] In addition to the effects of the second aspect of the invention, the method for manufacturing a breathable product according to the third aspect of the present invention can also adjust the range of increased hardness in the adhesive layer by controlling the cooling temperature, cooling time, etc. Therefore, the thickness of the exposed portion of the adhesive layer can be easily optimized through simple processing.

[0036] In addition to the effects of the third aspect of the invention, the method for manufacturing a breathable product according to the fourth aspect of the present invention allows the cooling process to be performed with a simple cooling unit because the adhesive layer is cooled via a release sheet. The release sheet makes the surface of the adhesive layer smooth and flat, thus obtaining a breathable product that is easy to adhere to an object.

[0037] In addition to the effects of the fourth aspect of the invention, the method for manufacturing a breathable product according to the fifth aspect of this invention, due to the large heat capacity and high thermal conductivity of the metal roller, can increase the hardness of a portion of the adhesive layer in a short time by contacting it with the release sheet. Therefore, the curing process of the adhesive layer can be accelerated, thereby improving the manufacturing efficiency of the breathable product.

[0038] In addition to the effects of any one of the first to fifth aspects, the method for manufacturing a breathable product according to the sixth aspect of the present invention, by pressing the adhesive layer onto the breathable substrate after pre-adjusting the hardness of the adhesive layer, can make the thickness of the nonwoven fabric, even if the thickness of the exposed portion of the adhesive layer is prone to become uneven, generally uniform.

[0039] In addition to the effects of any one of the inventions in the first to sixth aspects, the method for manufacturing a breathable product according to the seventh aspect of the present invention can manufacture a filter product that can be seamlessly attached to an object such as a vent, since the thickness of the exposed portion of the adhesive layer is appropriate.

[0040] In addition to the effects of any one of the third to fifth aspects of the invention, the method for manufacturing a breathable product according to the eighth aspect of the present invention, since the adhesive layer of the electrostatic filter is formed by a hot melt adhesive, suppresses the reduction of electrostatic function that occurs when the adhesive layer is formed by a conventional solvent-based adhesive, and can manufacture an electrostatic filter product with excellent capture efficiency for ultrafine particles such as PM2.5.

[0041] The manufacturing apparatus for a breathable product according to the ninth aspect of the present invention can provide an apparatus capable of manufacturing a breathable product in which an adhesive layer exposed to the surface of a breathable substrate has an appropriate thickness and the surface of the adhesive layer is formed by a release sheet to be flat and smooth.

[0042] In addition to the effects of the invention in the ninth aspect, the apparatus for manufacturing breathable products according to the tenth aspect of this invention also benefits from the fact that the metal roller, by appropriately setting its material and size, can possess high thermal conductivity and large heat capacity. Therefore, by cooling the release liner, the hardness of the adhesive layer near it can be increased in a short time. Furthermore, by appropriately setting the size and rotation speed of the metal roller, the contact area and contact time with the release liner can be controlled, and the range for increasing the hardness of the adhesive layer can be easily adjusted. Therefore, by including such a metal roller, a hardness adjustment unit with high control precision and reliability can be realized with a simple structure. Moreover, since the hardness adjustment process of the adhesive layer can be accelerated by using the metal roller, an apparatus for manufacturing breathable products that can efficiently produce a uniformly thick layer of the exposed portion of the adhesive layer can be provided. Attached Figure Description

[0043] Figure 1 This figure illustrates an example of a breathable product according to an embodiment of the present invention. Figure 1 (A) is a top view with a portion omitted. Figure 1 (B) is to Figure 1 (A) is a magnified section view of a portion of the data.

[0044] Figure 2 This is a schematic diagram illustrating an example of a manufacturing apparatus for producing a breathable product according to an embodiment of the present invention.

[0045] Figure 3 It is an enlarged representation Figure 2 The diagram of part A.

[0046] Figure 4 yes Figure 3 An enlarged sectional view of line IV-IV.

[0047] Figure 5 It is an enlarged representation Figure 2 The diagram in section B.

[0048] Figure 6 yes Figure 5 An enlarged sectional view of line VI-VI.

[0049] Figure 7 It is an enlarged representation Figure 2 The diagram in section C.

[0050] Figure 8 yes Figure 7 An enlarged sectional view of line VIII-VIII. Detailed Implementation

[0051] [Breathable products]

[0052] Figure 1 This figure illustrates an example of a breathable product according to an embodiment of the present invention. Figure 1 (A) is a top view with a portion omitted. Figure 1 (B) is a cross-sectional view of a portion of (A) that is enlarged.

[0053] Referring to the same figures, the breathable product F manufactured according to the present invention is, for example, a filter for adhering to an object to filter passing gas, comprising a breathable substrate S1 having a gap on at least one side and an adhesive layer N formed on a portion of one side of the breathable substrate S1. Additionally, in this embodiment, a release sheet S2 is included, disposed on the surface side of the adhesive layer N. A portion of the adhesive layer N penetrates into the gap of the breathable substrate S1.

[0054] The breathable substrate S1 can be made of nonwoven fabric, woven fabric, knitted fabric, or a combination thereof. Polypropylene or propylene-based copolymers are commonly used as the material for the breathable substrate S1. Additionally, to impart flame retardancy, fatty acid metal salts such as aluminum stearate, or flame-retardant fibers, may be added to the aforementioned synthetic resin raw materials in appropriate amounts.

[0055] When the breathable product F is a filter, the breathable substrate S1 is preferably configured with a thickness of 0.3 to 15.0 mm and a unit area weight of 20 to 200 g / m². 2 Within this range. If constructed in this way, it can reliably capture airborne dust while allowing gas to pass through, and possesses practical strength. This is suitable for thicknesses below 0.3 mm or weight per unit area below 20–200 g / m². 2 In some cases, the practical strength is insufficient, and it may not be able to perform its full trapping function. If the thickness exceeds 15.0 mm or the weight per unit area exceeds 200 g / m², it may also be insufficient. 2 If this happens, the resistance to gas flow increases, which may impair its practicality as an air filter.

[0056] The adhesive layer N is preferably a solvent-free adhesive such as a hot melt adhesive or a latex-type adhesive.

[0057] Conventional hot-melt adhesives can be used as hot-melt adhesives. Specifically, examples include ethylene vinyl acetate-based, polyolefin-based, polyamide-based, synthetic rubber-based, acrylic-based, and polyurethane-based hot-melt adhesives. Among these, considering factors such as holding power when applying to objects like vents and the difficulty of removing adhesive residue, synthetic rubber-based hot-melt adhesives are preferred for filters.

[0058] When using synthetic rubber-based hot melt adhesives, examples of synthetic rubber components that can be included include styrene-based elastomers such as styrene-butadiene block copolymers, styrene-isoprene block copolymers and hydrogenated products of these block copolymers, polyisobutylene, butyl rubber (isobutylene-isoprene copolymers and modified versions of this polymer), olefin-based elastomers such as polybutene, polychloroprene, and nitrile rubber. These synthetic rubber components function as elastomers, thereby improving the cohesiveness of the adhesive and thus enhancing its adhesive strength.

[0059] Alternatively, hot melt adhesives may contain one or more of the ingredients listed below.

[0060] • Tackifying resins such as rosin-based resins, terpene resins, (hydrogenated) petroleum resins, coumarone-indene resins, hydrogenated aromatic hydrocarbon copolymers, styrene-based resins, phenol-based resins, and xylene resins;

[0061] Phthalate esters, adipate esters, sebacic acid esters, other fatty acid esters, paraffin wax, epoxy polymer plasticizers, phosphate esters, nitrogen phosphate esters, propylene oligomers, polyisoprene, processing oils, naphthenic oils, polyester polyols, polyhydroxy polyethers, polyol compounds and other plasticizers;

[0062] • Ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, polyvinyl acetate and other polymers.

[0063] The above-mentioned components can be used alone or in combination. They are used as tackifiers in adhesives, improving the adhesion (bonding) of the adhesive to breathable substrates.

[0064] In addition to the components mentioned above, other components that can be included in hot melt adhesives include, for example, one or more of the following: petroleum-based hydrocarbons and other mineral oils (synthetic oils), vegetable oils, animal oils, alkanes, terpenoids, fatty acids, fatty acid esters, ethanol, honey, and clomiphene. These components all act as softeners in the adhesive, preventing the adhesive's adhesion from decreasing at low temperatures.

[0065] Furthermore, the aforementioned components also improve the coating adaptability of the adhesive. For example, depending on the type, molecular weight, and content of the elastomer component constituting the synthetic rubber-based hot melt adhesive, stringing or other issues may sometimes occur during adhesive coating. In such cases, adding a softener to the adhesive can appropriately prevent stringing and other issues, thus achieving good coating adaptability. Additionally, by including the aforementioned components in the adhesive, when the electrostatic filter structure of the present invention is peeled off from objects such as vents after use, residue of the hot melt adhesive relative to the object can be suppressed.

[0066] Release sheet S2 is made of a thin sheet material that can hold the applied adhesive on the surface without absorbing the adhesive, and also has good peelability to the adhesive. Examples of such materials include polyester films such as polyethylene terephthalate (PET) film and polyolefin films such as polypropylene (PP) film. Release agents such as silicone resins for improving peelability can also be coated on the surface of these films.

[0067] [Manufacturing Equipment]

[0068] Next, the manufacturing apparatus used to manufacture the breathable product of the present invention will be described.

[0069] Figure 2 This is a schematic diagram illustrating an example of a manufacturing apparatus for producing a breathable product according to an embodiment of the present invention.

[0070] Referring to the same figures, the manufacturing apparatus P of the present invention includes: a substrate supply unit for supplying a breathable substrate S1, a release sheet supply unit for supplying a release sheet S2, an adhesive supply unit for supplying an adhesive M, an adhesive coating unit for coating an adhesive M supplied from the adhesive supply unit onto a portion of one side of the release sheet S2 supplied from the release sheet supply unit to form an adhesive layer, a hardness adjustment unit for adjusting the hardness of the adhesive layer so that only a portion of the adhesive layer penetrates into the gaps of the breathable substrate S1, and a pressing unit for pressing the breathable substrate S1 supplied from the substrate supply unit onto the hardened adhesive layer.

[0071] In this embodiment, for example, the breathable substrate S1 is a non-woven fabric, the release sheet S2 is a PET film, and the adhesive M is a hot melt adhesive that is cured at room temperature and softened by heating.

[0072] Furthermore, in the manufacturing apparatus P of this embodiment, the supply unit for the breathable substrate S1 includes supply rollers 10 and 11 for supplying the breathable substrate S1 while adjusting its conveying speed, and conveying rollers 12, 13, and 14 for conveying the breathable substrate S1. The supply unit for the adhesive M includes an adhesive supply roller 2 for storing and dispensing the adhesive M, and an auxiliary roller 1. The adhesive coating unit includes a coating roller 3 for coating the adhesive M supplied from the adhesive supply roller 2 to form an adhesive layer N with a predetermined pattern, and a spare roller 4. The hardness adjustment unit includes a metal roller 7 that contacts the side of the release sheet S2 opposite to the side where the adhesive layer N is formed. The pressing unit includes clamping rollers 5 and 6 for bonding the breathable substrate S1 supplied from the breathable substrate supply unit and the release sheet S2 with adjusted adhesive layer hardness by stacking and pressing them together. Regarding the supply unit for the release sheet S2, a known structure can be used, and the figures are omitted.

[0073] The auxiliary roller 1, adhesive supply roller 2, coating roller 3, and spare roller 4 are arranged adjacently and configured to rotate in tandem. Molten adhesive M is stored in the upper part of the mating portion of the adhesive supply roller 2 and the auxiliary roller 1. When the adhesive supply roller 2 is rotated, the adhesive M adhering to its surface migrates to the surface of the coating roller 3 adjacent to it. The amount of adhesive M migration can be controlled by adjusting the gap size between the adhesive supply roller 2 and the auxiliary roller 1.

[0074] The coating roller 3 can be a known printing roller such as a gravure roller or a letterpress roller. In addition, by making the surface of the coating roller 3 a metal surface, the peelability is improved, so that the adhesive M can be smoothly migrated from the coating roller 3 to the release sheet S2.

[0075] When the release sheet S2 passes between the coating roller 3 and the spare roller 4, on which adhesive M migrates from the adhesive supply roller 2, is adhered, the adhesive M is applied to one side of the release sheet S2, forming an adhesive layer N. The adhesive layer N can also be in the form of text or a pattern.

[0076] The metal roller 7, which contacts the side of the release slab S2 opposite to the side where 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 dimensions. The contact area between the metal roller 7 and the release slab S2 can be set according to the diameter of the metal roller 7 or the position of the metal roller 7 relative to the path of the release slab S2. The metal roller 7 may also have a suitable heat dissipation mechanism or cooling mechanism. Furthermore, the metal roller 7 may also have the function of applying tension to the release slab.

[0077] [Manufacturing Method]

[0078] Next, the manufacturing method of the breathable product of the present invention using the above-described manufacturing apparatus P will be described.

[0079] Figure 3 It is an enlarged representation Figure 2 The diagram of part A. Figure 4 yes Figure 3 An enlarged sectional view of line IV-IV. Figure 5 It is an enlarged representation Figure 2 The diagram in section B. Figure 6 yes Figure 5 An enlarged sectional view of line VI-VI. Figure 7 It is an enlarged representation Figure 2 The diagram in section C. Figure 8 yes Figure 7 An enlarged sectional view of line VIII-VIII.

[0080] Referring to these figures, the manufacturing method of the present invention includes: a substrate preparation step, preparing a breathable substrate S1 having a gap on at least one side; a hardness adjustment step, preparing an adhesive layer for forming on a portion of one side, and adjusting the hardness of the adhesive layer so that only a portion of the adhesive layer penetrates into the gap of the breathable substrate S1; and a pressing step, pressing the hardened adhesive layer onto the breathable substrate S1.

[0081] In this embodiment, the substrate preparation process is performed by the supply unit of the breathable substrate S1. The adhesive layer preparation process is performed by the coating roller 3 in the step of applying adhesive M to one side of the release sheet S2. The hardness adjustment process is performed by bringing the metal roller 7 into contact with the side of the release sheet S2 on which the adhesive layer is formed. The pressing process is performed by passing the release sheet S2 with the adhesive layer formed and the breathable substrate S1 facing each other between the clamping rollers 5 and 6.

[0082] The manufacturing method of the breathable product F in this embodiment will now be described in detail.

[0083] Reference Figure 2 In the manufacturing apparatus P, by rotating the adhesive supply roller 2, the molten adhesive M stored in the upper part of the docking portion of the adhesive supply roller 2 and the auxiliary roller 1 migrates to the surface of the coating roller 3 which is in contact with the adhesive supply roller 2.

[0084] Moreover, such as Figure 3 As shown, by passing the release sheet S2 supplied from the supply unit between the coating roller 3 and the spare roller 4, adhesive M is applied to one side of the release sheet S2 according to a fixed pattern, such as... Figure 4 As shown, an adhesive layer N with a specified pattern is formed on the release sheet S2.

[0085] Next, the release sheet S2 with the adhesive layer N is conveyed to the position of the metal roller 7, as shown. Figure 5 As shown, the side without the adhesive layer N is engaged with the metal roller 7. The metal roller 7 is configured to have a lower temperature than the adhesive layer N, excellent thermal conductivity, and sufficient heat capacity. Therefore, as... Figure 6 As shown, since the adhesive layer N, which is in a softened state on the release sheet S2, is cooled by the metal roller 7 via the release sheet S2, the region near the release sheet S2 in the adhesive layer N becomes a hardening region N1, which becomes harder due to the decrease in temperature. Conversely, the surface side region of the adhesive layer N away from the release sheet S2 remains a softened state region N2 with fluidity.

[0086] Since the contact between the release sheet S2 and the metal roller 7 is approximately uniform in all areas, it is assumed that the temperature reduction of the adhesive layer N resulting from this contact is performed approximately uniformly. Therefore, the thickness of the region N1 with increased hardness in the adhesive layer N is approximately uniform.

[0087] In addition, Figure 6In the diagram, for ease of explanation, dashed lines are used to represent the boundaries of the two regions, the hardness-increasing region N1 and the softened state region N2. However, in reality, the hardness changes continuously from the region near the release piece S2 in the adhesive layer N to the surface side of the adhesive layer N away from the release piece S2.

[0088] Furthermore, since the degree and range of hardness increase of the adhesive layer N can be controlled by adjusting the temperature, thermal conductivity, heat capacity, contact area and contact time with the release sheet S2 of the metal roller 7, the layer thickness of the hardness increase region N1 can be easily adjusted.

[0089] In this way, the release sheet S2, which has undergone the hardness adjustment process of the adhesive layer N, is conveyed to the positions of the clamping rollers 5 and 6. On the other hand, the breathable substrate S1 is also conveyed to the positions of the clamping rollers 5 and 6 via the supply rollers 10 and 11 and the conveying rollers 12, 13 and 14. At this time, the conveying speeds of the breathable substrate S1 and the release sheet S2 are controlled so that they are aligned at the positions of the clamping rollers 5 and 6.

[0090] like Figure 7 As shown, the breathable substrate S1 and the release sheet S2 supplied to the clamping rollers 5 and 6 are passed between the clamping rollers 5 and 6 with the breathable substrate S1 facing the surface of the release sheet S2 where the adhesive layer N is formed. As a result, the adhesive layer N on the release sheet S2 is pressed onto the breathable substrate S1, thereby manufacturing a breathable product F that integrates the two.

[0091] When the adhesive layer N is pressed onto the breathable substrate S1, as Figure 8 As shown, the softened region N2 located on the surface side of the adhesive layer N penetrates into the voids of the breathable substrate S1 due to its fluidity. On the other hand, the hardened region N1 in the adhesive layer N, which is close to the release sheet S2, remains on the surface of the breathable substrate S1 due to its low fluidity and does not penetrate into the voids inside the breathable substrate S1.

[0092] The portion of adhesive layer N that penetrates into the breathable substrate S1 forms an anchoring layer R after curing, exhibiting excellent bonding strength relative to adhesive layer N. Therefore, when using the product, no adhesive residue remains on the surface of the adhesive layer N when peeling off the release sheet S2.

[0093] On the other hand, after the hardness-increasing region N1 of the adhesive layer N cures, an exposed layer Q is formed on the surface of the breathable substrate S1. By adjusting the thickness of the hardness-increasing region N1 to be approximately constant, the thickness of the exposed layer Q can also be formed appropriately and approximately uniformly. As a result, when the breathable product F is adhered to the object to be installed, gaps are less likely to form between it and the object. Furthermore, if the adhesive layer N has a low viscosity in the portion that penetrates into the breathable substrate S1, i.e., the softened state region N2, or if the porosity of the breathable substrate S1 is large, the adhesive layer N may penetrate into the porosity of the breathable substrate S1 beyond what is expected before the softened state region N2 cures, and may even penetrate into the side of the breathable substrate S1 opposite to the side where the exposed layer Q is formed. If such impregnation occurs, the following defects (hereinafter referred to as the first defect) may sometimes occur: when passing between clamping rollers 5 and 6, which are used to bond the breathable substrate S1 and the release sheet S2 by stacking and pressing them together, the adhesive layer N impregnated with the breathable substrate S1 adheres to the clamping roller 6, the laminate of the breathable substrate S1 and the release sheet S2 becomes entangled on the clamping roller 6, or the laminate of the breathable substrate S1 and the release sheet S2 separates because only the breathable substrate S1 adheres to the clamping roller 6 and is stretched, or the breathable substrate S1 is damaged because a portion of it is stretched to the clamping roller 6 side. Furthermore, even when passing between clamping rollers 5 and 6, if a conveyor roller (not shown) is used in the next process, a defect (hereinafter referred to as the second defect) also occurs because the breathable substrate S1 adheres to the conveyor roller, just as the adhesive layer N adhered to the clamping roller 6. To prevent these first and second defects, the softened region N2 can be cooled and solidified before the adhesive layer N penetrates into the surface of the breathable substrate S1 opposite to the surface where the exposed layer Q is formed. For this purpose, for example, to address the first defect, a cooling mechanism can be provided on the clamping roller 6 itself on the side in contact with the breathable substrate S1; to address the second defect, a cooling mechanism can be provided between the clamping roller 6 and the conveying roller of the next process to cool the surface of the breathable substrate S1 opposite to the surface where the exposed layer Q is formed. However, even with such a cooling mechanism, it is preferable to balance the cooling rate to avoid hindering the adhesive layer N from penetrating the breathable substrate S1 and thus preventing the formation of the aforementioned anchoring layer R.

[0094] The breathable product F manufactured as described above is cut into specified sizes as needed to form a product, which is then sold as a filter product with a release sheet. In use, at the work site, the release sheet S2 is peeled off, and the breathable substrate S1, made of non-woven fabric or the like, is partially adhered to the object using the adhesive layer N.

[0095] Furthermore, in this embodiment, the adhesive layer N is not formed on the entire surface of the breathable substrate S1, but rather locally through a patterned coating. When the adhesive M is a hot-melt adhesive, the coating amount is preferably 20–50 g / m². 2 More preferably 25-35 g / m 2 Furthermore, the preferred coating area of ​​the hot melt adhesive is typically in the range of 40% to 80% of the entire breathable substrate S1. However, the above values ​​can be appropriately varied depending on the application or size of the breathable product F.

[0096] [Other Implementation Methods]

[0097] The embodiments of the present invention are not limited to those described above.

[0098] In addition to nonwoven fabrics, woven fabrics, knitted fabrics, or combinations thereof can also be used as breathable substrates.

[0099] In addition to hot melt adhesives, latex-based adhesives and UV-curing adhesives can also be used as adhesives.

[0100] Besides using metal rollers, the hardness of the adhesive layer can also be adjusted by having a conveyor belt moving at the same speed as the release sheet contact the side of the release sheet opposite to the side where the adhesive layer forms. Alternatively, it can be done by spraying cooling gas onto the opposite side. When using a UV-curable adhesive, the hardness of the adhesive layer can be adjusted by irradiating the side of the release sheet opposite to the side where the adhesive layer forms with ultraviolet light.

[0101] The adhesive supply unit can also be prepared with a tank for storing adhesive in a fluid state, from which adhesive is supplied directly to the adhesive supply roller.

[0102] In addition to roller coating, which involves applying the adhesive using a coating roller, other methods for adhesive application include spraying, jetting, die coating, and screen printing.

[0103] In addition to household appliances such as range hoods, air conditioners, air purifiers, and exhaust fans in kitchens and stoves, the breathable products manufactured according to the present invention can also be widely used as indoor and outdoor ventilation openings, air filter products for ventilation parts in industrial equipment, or as constituent materials for breathable hygiene products such as masks, diapers, bed sheets, and clothing.

[0104] Furthermore, this invention can be applied to the manufacture of electrostatic filters. Because electrostatic filters can utilize electrostatic force to efficiently capture and remove microparticles from gases, effectively removing ultrafine particles with a diameter of less than 2.5 μm, known as PM2.5, which can have serious effects on the human respiratory system, their applications have been expanding in recent years.

[0105] In the manufacture of the electrostatic filter according to the present invention, the breathable substrate is a nonwoven fabric with electrostatic properties. Examples of such nonwoven fabrics include, for instance, nonwoven fabrics that have undergone electrostatic processing on a combination of polyester fibers (PET fibers) and modified polyacrylonitrile fibers, nonwoven fabrics that have undergone electrostatic processing on polypropylene nonwoven fabrics through corona discharge treatment, nonwoven fabrics that have undergone tanning after resin processing of wool-containing nonwoven fabrics and then undergone electrostatic processing, and nonwoven fabrics whose fiber surfaces are polarized and charged by using an external electrode to generate a high DC electric field on the surface of a core-sheath type composite fiber covered with polyethylene resin.

[0106] Furthermore, when manufacturing electrostatic filters based on the present invention, the use of hot-melt adhesives in the adhesives improves the capture effect of ultrafine particles such as PM2.5 compared to the use of conventional solvent-based adhesives.

[0107] If a hot-melt adhesive is used, the details of the mechanism by which it improves PM2.5 collection efficiency compared to conventional solvent-based adhesives are unclear. As a hypothesis, it is speculated that conventional adhesives, for example, diluted with solvents such as ethyl acetate, generate static electricity at the interface between the adhesive and the electrostatic filter, or within the adhesive itself, due to the flow during application. To counteract the charge carried by the electrostatic filter, this may reduce the PM2.5 collection efficiency of the electrostatic filter structure.

[0108] Therefore, based on the above speculation, the reason why the collection efficiency of PM2.5 is improved by using hot melt adhesive is that the adhesive flows less when it is pressed onto the breathable substrate. In addition, since it does not contain solvents, it is not easy to generate static electricity at the interface with the breathable substrate or inside the adhesive layer.

[0109] Furthermore, the present invention can be applied and modified in various ways depending on the implementation.

[0110] Industrial availability

[0111] Since the present invention can manufacture breathable products with uniform thickness of adhesive layer formed on breathable substrates such as non-woven fabrics, it can provide air filter products with good installability and low adhesive residue, such as range hoods, air conditioners, air purifiers, exhaust fans, and vents, or breathable hygiene products that are intended for installation.

Claims

1. A method for manufacturing a breathable product (F), comprising: The substrate preparation process involves preparing a breathable substrate with gaps on at least one side (S1). A hardness adjustment step involves preparing an adhesive layer (N) for formation on a portion of one side, and adjusting the hardness of the adhesive layer so that only a portion of the adhesive layer penetrates into the gaps of the breathable substrate; and In the pressing process, the adhesive layer with adjusted hardness is pressed onto the breathable substrate. The hardness adjustment process includes a hardness increasing process, which increases the hardness of the region in the adhesive layer containing the side opposite to the side pressed by the breathable substrate. The adhesive layer is composed of a hot-melt adhesive (M). The hardness-increasing process includes a cooling process that cools the region in the softened adhesive layer.

2. The method for manufacturing a breathable product according to claim 1, wherein, The cooling process includes the following steps: preparing a release sheet (S2) on one side to form an adhesive layer composed of a softened hot melt adhesive, and cooling the side of the release sheet opposite to the side on which the adhesive layer is formed.

3. The method for manufacturing a breathable product according to claim 2, wherein, The process of cooling the release sheet includes engaging a metal roller (7) with the release sheet at a temperature lower than that of the adhesive layer.

4. The method for manufacturing a breathable product according to any one of claims 1 to 3, wherein, The breathable substrate is made of non-woven fabric.

5. The method for manufacturing a breathable product according to any one of claims 1 to 3, wherein, The breathable product is a filter.

6. The method for manufacturing a breathable product according to any one of claims 1 to 3, wherein, The breathable product is an electrostatic filter.

7. An apparatus (P) for manufacturing a breathable product, for manufacturing a breathable product having an adhesive layer (N) formed on a portion of one side of a breathable substrate (S1), wherein, include: Substrate supply unit (10-14) for supplying a breathable substrate having a gap on at least one side; Release sheet supply unit, used to supply release sheets (S2). Adhesive supply unit (1, 2) is used to supply adhesive (M). Adhesive coating units (3, 4) are used to coat the adhesive supplied from the adhesive supply unit onto a portion of one side of the release sheet supplied from the release sheet supply unit to form an adhesive layer; A hardness adjustment unit (7) is used to adjust the hardness of the adhesive layer so that only a portion of the adhesive layer formed by the adhesive coating unit penetrates into the gaps of the breathable substrate; as well as Pressing units (5, 6) are used to press the breathable substrate supplied from the substrate supply unit onto the adhesive layer whose hardness has been adjusted. The adhesive is a hot melt adhesive. The hardness adjustment unit includes a metal roller (7), which engages with the release sheet on which the adhesive layer is formed, and cools the release sheet.

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