JP2014121699A - Air filter filter material and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air filter filter material of an air filter incorporated in an air conditioner and air cleaner or the like, in which a base material, ultrafine fibers, and a protection layer for protecting them are adhered while maintaining good air permeability.SOLUTION: An air filter filter material 11 includes a base material 12, an ultrafine fiber layer 13 formed of ultrafine fibers having a diameter of 100 nm to 1 μm, and a protection layer 14 for protecting the ultrafine fiber layer. The ultrafine fiber layer 13 and an adhesive material 15 are arranged between the base material 12 and the protection layer 14. The adhesive material 15 passes through a part of the ultrafine fiber layer 13 to adhere the base material 12 and the protection layer 14. Thereby, an amount of the adhesive material for adhering the base material, the ultrafine fibers, and the protection layer can be further reduced, and good air permeability as the air filter filter material can be maintained while being adhered strongly.

Description

  The present invention relates to an air filter medium including ultrafine fibers in an air filter incorporated in an air conditioner, an air purifier, and the like, and a method for manufacturing the same.

  Conventionally, as this type of air filter medium, there has been known a heat-adhesive composite sheet in which an ultrafine fiber layer and a heat-fusible fiber layer are joined by pressing with a heating roll through a fibrous sheet made of a hot-melt resin. (For example, refer to Patent Document 1).

  Hereinafter, the heat-adhesive composite sheet will be described with reference to FIG.

  As shown in FIG. 8, the heat-adhesive composite sheet is formed by a melt blow method by forming an ultrafine fiber layer 101 having an average fiber diameter of 0.1 to 5 μm and a heat-fusible fiber layer 102 having an average fiber diameter of 6 to 30 μm. It is bonded by pressing with a heating roll through a fibrous sheet 103 made of hot melt resin.

  Further, as this type of air filter medium, a multilayer sheet is known in which a fiber sheet is provided with an ultrafine fiber layer and these are bonded with a resin derived from a liquid binder (see, for example, Patent Document 2).

  Hereinafter, the multilayer sheet will be described with reference to FIG.

  As shown in FIG. 9, the multilayer sheet is an ultrafine fiber having an average fiber diameter of 1 μm or less produced by an electrospinning method on the conductive surface side of the fiber sheet 201 having conductivity on at least a part of one surface. The fiber sheet 201 and the ultrafine fiber layer 202 are adhered by a resin 203 derived from a liquid binder.

Japanese Patent No. 47488838 Japanese Patent No. 4979407

  In a conventional air filter medium such as Patent Document 1, the ultrafine fiber layer 101 and the heat-fusible fiber layer 102 are joined by pressing with a heating roll via a fibrous sheet 103 made of a hot-melt resin. Therefore, the fibrous sheet 103 made of a hot-melt resin needs to have a strength capable of maintaining its shape independently. Therefore, more adhesive than the amount necessary for the adhesion between the ultrafine fiber layer 101 and the heat-fusible fiber layer 102 spreads to the ultrafine fiber layer 101, the effective portion of the ultrafine fiber layer 101 is blocked, and the air permeability is deteriorated. There was a problem.

  Further, in the air filter medium of Patent Document 2, since the liquid sheet 201 provided with the ultrafine fiber layer 202 is provided with a liquid binder, dried, and bonded with a resin derived from the liquid binder, the liquid binder However, there is a problem that a large amount of the fiber penetrates into the inside of the ultrafine fiber layer 202 by a capillary phenomenon, a resin film is formed at the entangled portion of the fiber, an effective portion of the ultrafine fiber layer 202 is blocked, and air permeability is deteriorated. .

  Furthermore, when providing a protective layer on these air filter media, in addition to the adhesion between the substrate and the ultrafine fiber layer, adhesion including the protective layer is required, and there is a problem that air permeability is further deteriorated. It was.

  Therefore, the present invention solves the above-described conventional problems, and is an air filter medium capable of bonding a base material, an ultrafine fiber, and a protective layer for protecting the base material while maintaining good air permeability. The purpose is to provide.

  In order to achieve this object, the present invention provides an air filter medium having a base material, an ultrafine fiber layer composed of ultrafine fibers having a diameter of 100 nm to 1 μm, and a protective layer for protecting the ultrafine fiber layer. In the method, an ultrafine fiber layer and an adhesive material are provided between the base material and the protective layer, and the adhesive material penetrates a part of the ultrafine fiber layer to adhere the base material and the protective layer. It is a feature that achieves the intended purpose.

  Moreover, in the air filter medium which has a base material, the ultrafine fiber layer which consists of an ultrafine fiber with a diameter of 100 nm or more and 1 micrometer or less, and the protective layer for protecting the said ultrafine fiber layer, the adhesive layer by an adhesive material on the base material surface And an extra fine fiber layer, and after further stacking the protective layer, these are pressure-bonded, and the base material and the protective layer are adhered by an adhesive, and the adhesive is a part of the extra fine fiber layer. This is a method for producing an air filter medium that penetrates and adheres the base material and the protective layer, thereby achieving the intended purpose.

  According to the present invention, in an air filter medium having a base material, an ultrafine fiber layer composed of ultrafine fibers having a diameter of 100 nm to 1 μm, and a protective layer for protecting the ultrafine fiber layer, the base material and the protective layer A fine fiber layer and an adhesive, and the adhesive penetrates a part of the ultrafine fiber layer to bond the base material and the protective layer. The amount of adhesive for adhering the material, ultrafine fibers, and protective layer can be reduced, and while these are firmly bonded, good air permeability as an air filter medium can be maintained. is there.

  Further, according to the present invention, after providing an adhesive on the surface of the base material, an ultrafine fiber layer is provided thereon, a protective layer is further stacked, and then these are crimped to protect the base material with the adhesive. By adhering layers, the adhesive material penetrates a part of the ultrafine fiber layer and adheres the base material and the protective layer. An air filter medium that can maintain good air permeability as a filter medium can be easily manufactured.

1 is a schematic cross-sectional view showing an air filter medium according to Embodiment 1 of the present invention. Schematic which shows an example of the presence state of the adhesive material of the air filter medium Schematic which shows an example of the presence state of the adhesive material of the air filter medium Schematic sectional view showing an example of a state in the middle of manufacturing the air filter medium Schematic sectional view showing an example of a state in the middle of manufacturing the air filter medium Schematic showing an example of a method for producing the air filter medium Schematic showing an example of a method for producing the air filter medium Schematic cross section showing a conventional air filter medium Schematic cross section showing a conventional air filter medium

  An air filter medium according to claim 1 of the present invention includes a base material, an ultrafine fiber layer made of ultrafine fibers having a diameter of 100 nm or more and 1 μm or less, and a protective layer for protecting the ultrafine fiber layer. And an ultrafine fiber layer and an adhesive material between the base material and the protective layer, wherein the adhesive material penetrates a part of the ultrafine fiber layer and adheres the base material and the protective layer. And

  Thereby, the amount of the adhesive for bonding the base material, the ultrafine fiber, and the protective layer can be reduced, and the air filter medium can be used while the base material and the protective layer are firmly bonded via the ultrafine fiber. As a result, it is possible to maintain good air permeability.

  Moreover, the base material may be a sheet made of resin. Thereby, it is possible to obtain an effect that the tensile strength is higher than that of a sheet such as paper and the filter medium is not easily broken during winding or subsequent pleating. Since it is difficult to break, it is possible to prevent deformation of the bonded portion of the base material and the ultrafine fiber and the base material and the protective layer, and it is possible to provide an air filter medium that can be bonded while maintaining good air permeability. Moreover, the density structure of the resin sheet which comprises a base material, a fiber diameter, etc. can be controlled easily, and the sheet | seat suitable for the characteristic of an ultrafine fiber layer can be obtained. Furthermore, if the resin sheet is charged, an effect of collecting dust in the air with high efficiency can be added to the air filter medium.

  The base material may be a sheet made of glass fiber. Thereby, the stiffness suitable for pleating can be imparted to the air filter medium. Furthermore, since the material stability is excellent, the function of the base material itself can be stably obtained without being affected by the type of the adhesive layer and the adhesion method.

  Further, the substrate may be colored. Thereby, it can be easily visually recognized or detected by an apparatus whether or not the adhesive layer is provided. Furthermore, when colored using a functional material, a function can be added to the air filter medium.

  Further, the protective layer may be a sheet made of resin fiber. Thereby, the density structure of the sheet | seat which comprises a protective layer, a fiber diameter, etc. can be controlled easily, and the sheet | seat suitable for the characteristic of an ultrafine fiber layer can be obtained. Furthermore, if the sheet | seat which consists of resin fibers is electrified, the effect which can collect the dust in air | atmosphere with high efficiency can be added to an air filter filter medium.

  Moreover, the manufacturing method of the air filter medium of Claim 6 of this invention is a base material, the ultrafine fiber layer which consists of an ultrafine fiber with a diameter of 100 nm or more and 1 micrometer or less, and the protective layer for protecting the said ultrafine fiber layer. In an air filter medium having an adhesive layer, an adhesive layer made of an adhesive and an ultrafine fiber layer are provided on the surface of the base material. And the said adhesive material penetrates a part of said ultrafine fiber layer, and makes it adhere | attach the said base material and the said protective layer.

  As a result, an air filter medium that can maintain good air permeability as an air filter medium can be easily manufactured while the base material, the ultrafine fibers, and the protective layer for protecting the substrate are firmly bonded. There is an effect.

  In addition, after providing an adhesive layer with an adhesive on the surface of the substrate, the ultrafine fiber layer is provided thereon, and the protective layer is further stacked, and then crimped from both sides in the laminating direction, and the base is formed by the adhesive. The material and the protective layer are bonded together.

  As a result, unevenness due to the thickness of the adhesive layer is formed on the substrate, and the ultrafine fiber layer is provided thereon, so that the ultrafine fiber layer forms a layer with three-dimensional voids, and pressure It is possible to obtain the effect of extending the life by reducing the loss and increasing the dust holding space.

  Further, the adhesive layer is formed by spraying hot-melt powdery particles on the substrate surface. By spraying the adhesive in the form of a heat-meltable powder, the amount of the adhesive that causes the powder to fall on the surface of the base material at an appropriate interval to bond the base material, the ultrafine fiber, and the protective layer As a result, it is possible to maintain good air permeability as an air filter medium while the base material and the protective layer are firmly bonded via the ultrafine fibers.

  Further, the base material is a sheet made of resin, and the base material and the protective layer are bonded while heating to melt the adhesive. Thereby, the temperature rise rate of the resin of the base material and the adhesive becomes close at the time of heating, and the adhesive can be uniformly melted to firmly bond the base material and the protective layer. Further, only a part of the adhesive is excessively melted, and the clogging of the voids due to the penetration of the molten resin into the base material can be prevented, and adhesion can be performed while maintaining good air permeability.

  Moreover, the particle diameter of the adhesive is larger than the diameter of the ultrafine fibers. Accordingly, the adhesive can surely pass through the ultrafine fibers, and the base material and the protective layer can be firmly bonded to each other while maintaining good air permeability.

  Further, the adhesive has a particle size distribution, and the relative ratio of the large particle size to the small particle size is at least twice. By changing the size of the adhesive, the uneven shape formed by the adhesive spread on the surface of the base material changes, and the ultrafine fiber layer is provided on the uneven shape. The layer is formed in a form having voids, and the effect of improving the air permeability and extending the service life by reducing the pressure loss and increasing the dust holding space can be obtained.

  Further, the adhesive layer is formed by spraying a heat-meltable material on the surface of a base material, an ultrafine fiber layer is provided thereon, and a protective layer is further stacked, and then these are heated and bonded. Also good. Thereby, since the ultrafine fibers are easily embedded in the adhesive layer, it is not necessary to apply high pressure for pressure bonding, and the base material, the ultrafine fiber layer, and the protective layer can easily maintain the initial shape. Furthermore, the base material and the protective layer can be more firmly bonded at room temperature.

  Moreover, the manufacturing method which made the heating direction from the base-material side may be sufficient. Thereby, heat is easily transmitted to the adhesive layer provided on the surface of the substrate, and sufficient adhesive strength can be obtained in a shorter time and with less energy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, the air filter medium 11 includes a base 12, an ultrafine fiber layer 13 made of ultrafine fibers having a diameter of 100 nm to 1 μm, and a protective layer 14 for protecting the ultrafine fiber layer. An ultrafine fiber layer 13 and an adhesive material 15 are provided between the base material 12 and the protective layer 14, and the adhesive material 15 penetrates a part of the ultrafine fiber layer 13 to adhere the base material 12 and the protective layer 14. . FIG. 2 shows a state of the powdery adhesive 15 spread on the surface of the substrate 12. FIG. 3 shows a state of the fibrous adhesive 15 sprayed on the surface of the base material 12 in a molten state. 4 and 5 are schematic cross-sectional views showing an example of a state during the production of the air filter medium. 6 and 7 show an example of a method for manufacturing the air filter medium 11 of the present invention.

  In the case of using a powdery adhesive as shown in FIG. 2, the adhesive 15 is made to be scattered by spraying a powdery adhesive on the surface of the substrate 12, and then the electrospinning method is applied thereon. After providing the ultrafine fiber layer 13 and further stacking the protective layer 14, these are pressure-bonded, and the base material 12 and the protective layer 14 are bonded by the adhesive 15 via the ultrafine fiber layer 13, that is, the adhesive 15 However, the base material 12 and the protective layer 14 are bonded to each other through a part of the ultrafine fiber layer 13. Here, it is preferable that the adhesives do not overlap each other in the dispersion of the adhesive. It is preferable that the adhesive is scattered at an appropriate interval with a gap larger than the particle diameter of the adhesive. In the case of 40 μm adhesive particles, by spacing 40 μm or more around the periphery, even if the adhesive melts, the adhesives do not come into contact with each other, and can be bonded while maintaining good air permeability. it can.

  In FIG. 5, another example of the manufacturing method of the air filter medium 11 of this invention is shown. An ultrafine fiber layer 13 is provided on the surface of the base material 12 by electrospinning, and an adhesive 15 is provided in a fiber shape by spraying thereon. After that, a protective layer 14 is further stacked thereon, and then these are pressure-bonded. Then, the base material 12 and the protective layer 14 are bonded to each other by the adhesive 15 via the ultrafine fiber layer 13, that is, the adhesive 15 penetrates a part of the ultrafine fiber layer 13 and the base 12 and the protective layer 14 Adhere.

  In the present invention, when the powdery adhesive 15 is used as shown in FIG. 2, the adhesive 15 is provided in a state where the adhesive is scattered at intervals. The adhesive material 15 should just ensure the minimum which can penetrate the part of the ultrafine fiber layer 13, and can adhere | attach the base material 12 and the protective layer 14. FIG. The particle diameter of the adhesive 15 is desirably larger than the fiber diameter of the ultrafine fiber so as to penetrate the ultrafine fiber layer 13.

  Moreover, as shown in FIG. 3, when using the adhesive material 15 which melts a hot-melt resin material and sprays it from a nozzle, the adhesive material 15 is provided in the form of a fiber at intervals. The fiber diameter and the amount of the adhesive material 15 are arbitrary, and it is sufficient that the minimum that allows the base material 12 and the protective layer 14 to be bonded through a part of the ultrafine fiber layer 13 is ensured. Further, a liquid adhesive diluted with an organic solvent or water may be used.

  As a result, as described in the background art, the effective portion of the ultrafine fiber layer 13 generated when the fibrous sheet having adhesiveness is inserted and bonded, or the entanglement of fibers generated when the liquid binder is applied and bonded It is possible to avoid clogging of the effective portion of the ultrafine fiber layer 13 due to the formation of the resin film in the portion.

  Thus, the amount of the adhesive material for bonding the base material 12, the ultrafine fiber layer 13, and the protective layer 14 is further reduced by making the adhesive material 15 into a fibrous shape and setting the distance between the fibers to be equal to or greater than a certain distance. It is possible to maintain good air permeability as an air filter medium while these are firmly bonded.

  The substrate 12 is not particularly limited as long as it has air permeability, such as a sheet made of glass fiber, a sheet made of resin fiber, paper, and a metal net. When a sheet made of glass fiber is used, the stiffness necessary for pleating the air filter medium can be obtained. Furthermore, since the material stability is excellent, the function of the base material itself can be stably obtained without being affected by the type of the adhesive layer and the adhesion method.

  When the ultrafine fiber layer 13 is obtained by, for example, an electrospinning method, the substrate 12 is preferably conductive. In addition, when heating is performed when the base material 12 and the protective layer 14 are bonded, it is preferable to select a material having excellent heat resistance. In addition, when a high pressure is applied at the time of crimping, it is preferable to select a sheet whose structure does not easily collapse.

  If the base material 12 is colored, it is easy to determine whether or not an adhesive layer is provided when a material that does not easily give color, such as a hot melt adhesive, a rubber adhesive, or a resin emulsion, is used as the adhesive 15. It can be detected visually or by a device.

  Moreover, if the base material 12 and the protective layer 14 have different colors, the air filter medium 11 will have a different color on the front and back, making it easy to distinguish between the front and the back during molding or use by the user. Furthermore, for example, when a functional material such as carbon fiber is mixed with the base material 12 and colored, the air filter medium 11 can be provided with functions such as deodorizing performance and conductivity.

  The protective layer 14 may be made of the same material as the substrate 12 or may be different. When the protective layer 14 is a sheet made of a resin fiber, the density structure of the sheet constituting the protective layer, the fiber diameter, and the like can be easily controlled, and a sheet suitable for the characteristics of the ultrafine fiber layer 13 can be obtained.

  For example, if the length of the ultrafine fiber is 1 mm, by controlling the basis weight of the resin fiber so that the hole diameter in the sheet is 1 mm or less, the ultrafine fiber that is not present in the adhesive 15 is removed from the air filter medium 11. Can be prevented from being released to the outside.

  Furthermore, if the sheet | seat which consists of resin fibers is electrified, the effect which draws in the dust in air | atmosphere with static electricity can be added to the air filter medium 11, and the high dust collection effect can be given to the air filter medium 11. .

  As a manufacturing process of the air filter medium 11 of the present invention, after the ultrafine fiber layer 13 is provided on the surface of the base material 12, a method of providing the adhesive material 15 thereon, or after the adhesive material 15 is provided on the surface of the base material 12 And a method of providing the ultrafine fiber layer 13 thereon. FIG. 4 is a cross-sectional view schematically showing this state. In FIG. 4A, the ultrafine fiber layer 13 is formed on the surface of the substrate 12, and the layer of the adhesive 15 is formed thereon. On the other hand, as shown in FIG. 4B, in the method of providing the adhesive material 15 on the surface of the base material 12 and then providing the ultrafine fiber layer 13 thereon, irregularities due to the thickness of the adhesive layer are formed on the base material. The ultrafine fiber layer is provided thereon. In FIG.4 (b), a microfiber layer will form a layer in the form which has a three-dimensional space | gap, and the effect of the lifetime improvement by the fall of a pressure loss and the increase in dust holding space can be acquired.

  Examples of the adhesive 15 include a method of spraying with a spray 16 or the like while heating a heat-meltable material in a fluid state, and a method of spraying a powdery adhesive from above. When the heat-meltable material is heated and sprayed using the spray 16, the adhesive 15 can be easily made into a fiber by controlling the discharge amount of the adhesive 15 and the amount of extrusion gas. The fiber diameter can also be changed, and can be controlled, for example, to about 1 μm to 1 mm. In the case of a powdery adhesive, the size can be controlled by selecting an adhesive of any size.

  A heat-meltable material may be used as the adhesive. As a hot-melt adhesive, a hot-melt adhesive having a polyolefin as a main ingredient and having a softening temperature of about 90 ° C. is well known. Since the viscosity of the heat-meltable material changes depending on the heating temperature, the adhesive can be easily made fibrous by adjusting this temperature. As an example, materials such as vinyl acetate, polyacrylamide, and polyester can be used. The melting point and softening point can be changed by changing the amount of materials mixed and the degree of polymerization. For example, the base material 12 and the protective layer 14 can be bonded by heating a copolymer polyester having a melting point of 97 ° C. to 120 ° C.

  The powdery adhesive may have a particle size distribution. When the base material 12 and the protective layer 14 are bonded to each other through a part of the ultrafine fiber layer 13 having a diameter of 100 nm or more and 1 μm or less, the particle diameter of the adhesive is about 40 μm to 1700 μm (ratio of large particle diameter / small particle diameter) = 42.5 times).

  When the adhesive is pressure-bonded, the adhesive is crushed, blocking the ventilation path of the air filter medium, and the pressure loss increases. In order to secure the strength by bonding the base material 12 and the protective layer 14 while suppressing an increase in pressure loss as much as possible, a more preferable particle diameter of the adhesive is about 40 μm to 500 μm (ratio of large particle diameter / small particle diameter). = 11.4 times), and more preferably 40 to 80 µm (ratio of large particle size / small particle size = 2 times).

  In the method of spraying using the spray 16 or the like while heating the heat-meltable material in a fluid state, the adhesive 15 can be directly applied to the surface of the base material 12 with an interval corresponding to the diameter thereof. The material 15 can be made into the minimum quantity required for adhesion | attachment with the base material 12, the ultrafine fiber layer 13, and the protective layer 14 for protecting it.

As an example of the application amount of the adhesive 15, for example, the intended purpose can be achieved by setting the diameter of 40 μm to about 2 to 10 g / m ² , more preferably about 4 to 5 g / m ^2. it can. Here, the above-described interval is set according to the basis weight of the adhesive material 15.

  As a method of providing the ultrafine fiber layer 13 on the surface of the base material 12 provided with the adhesive 15, spraying directly from the nozzle 17 by an electrospinning method or placing a preformed ultrafine fiber sheet may be used. The electrospinning method can be directly sprayed on the surface of the base material 12, so that even the air filter medium having a configuration in which the ultra-fine fiber layer 13 has a low basis weight and cannot exist independently can be easily manufactured. be able to.

  Further, as a manufacturing process, after the powdery adhesive 15 was scattered on the surface of the base material 12 by the spray 16, the ultrafine fiber layer 13 was provided thereon by the electrospinning method, and the protective layer 14 was further stacked. Thereafter, by bonding these together, the base material 12 and the protective layer 14 can be adhered by the adhesive 15, and at least a part of the ultrafine fibers can be present in the adhesive 15.

  Further, in the manufacturing process, if the ultrafine fiber layer 13 from the nozzle 17 is formed by electrospinning immediately after the adhesive material 15 is sprayed, at least a part of the ultrafine fiber is landed on the adhesive material 15. The adhesive 15 includes adhesives having different particle diameters, and the landing heights of the ultrafine fibers are different from each other. Further, immediately after that, if the protective layer 14 is stacked and thermocompression bonded, the adhesive 15 penetrates the ultrafine fiber layer 13 and bonds the base material 12 and the protective layer 14 together.

  In the manufacturing process, after the ultrafine fiber layer 13 is provided on the surface of the base material 12 by electrospinning, and the adhesive 15 is provided in a fiber shape by the spray 16, the protective layer 14 is further stacked thereon. By crimping these, the base material 12 and the protective layer 14 can be adhered by the adhesive 15, and at least a part of the ultrafine fibers can be present in the adhesive 15.

  In the manufacturing process, if the adhesive 15 is formed immediately after forming the ultrafine fiber layer 13 from the nozzle 17 by electrospinning, at least a part of the ultrafine fibers immediately enters the adhesive layer of the adhesive 15. . Further, immediately after that, if the protective layer 14 is stacked and pressure-bonded, the adhesive 15 can penetrate the ultrafine fiber layer 13 to bond the base material 12 and the protective layer 14 together.

  When a heat-meltable material is used instead of a room temperature type adhesive containing an organic solvent as the adhesive, the ultrafine fibers are contained in the adhesive 15 due to the softening of the adhesive by heat and the contracting action by natural cooling. Since it becomes easy to bury, it is not necessary to apply a high pressure for pressure bonding, and the base material 12, the ultrafine fiber layer 13, and the protective layer 14 can easily maintain the initial shape. Further, in the hot melt material, VOC (volatile organic chemical substance) is not generated from the air filter due to the remaining organic solvent or the like.

  Moreover, even if the formation of the adhesive 15 and the formation of the ultrafine fiber layer 13 and the crimping step are divided, the desired configuration can be obtained by finally heating.

  An appropriate heating direction can be selected depending on the positions of the base material 12, the adhesive 15, and the ultrafine fiber layer 13. When the adhesive 15 is formed on the base 12 and the ultrafine fiber layer 13 is further formed, heat is transferred to the adhesive 15 on the surface of the base 12 by heating from the base 12 side. It is easy, and sufficient adhesive strength can be obtained in a shorter time and with less energy. When the ultrafine fiber layer 13 is formed on the base material 12 and the adhesive material 15 is further formed, if the heating is performed from the protective layer 14 side, the heat can be easily transferred to the adhesive material 15 for a shorter time. Thus, sufficient adhesive strength can be obtained with less energy.

  Although it is possible to heat from the opposite direction to the above, in that case, it is necessary to transmit thermal energy to the adhesive 15 sandwiched between the base material 12 and the protective layer 14, so the material of the protective layer 14 It is better to select one that can withstand it. Examples of materials that efficiently transmit thermal energy and are excellent in heat resistance include metal meshes.

  As the substrate 12, a sheet made of glass fiber, a sheet made of resin fiber, or the like can be used. FIG. 5A is a schematic diagram of the heating state when the base material is glass fiber when heated from the base material side, and FIG. 5B is a schematic diagram when the base material is resin fiber. Glass has better thermal conductivity than resin. Specifically, the thermal conductivity of glass is 0.74 W / mK, the resin polypropylene is 0.13 W / mK, polyethylene is 0.33 W / mK, and polyethersulfone is 0.2 W / mK. When the base material 12 is a glass fiber, since the heat conduction of the glass is good when heated from the base material 12 side, the contact surface of the adhesive 15 with the base material is dissolved first, and the non-contact surface remains solid. An intermediate state occurs. In this state, when the base material 12 and the protective layer 14 are pressure-bonded, it is conceivable that the adhesive 15 is not uniformly crushed and the three-dimensional void formed by the ultrafine fibers is compressed. On the other hand, when the base material 12 is a resin fiber, even if it heats from the base material 12 side, since the thermal conductivity of the base material 12, the ultrafine fiber layer 13, and the adhesive material 15 is close, the adhesive material 15 is melted as a whole. When the pressure bonding is performed, the ultrafine fiber layer 13 is buried in the adhesive material 15. Thereby, the effect that the three-dimensional space formed by the ultrafine fibers is held without being compressed can be obtained.

  The air filter medium according to the present invention and the manufacturing method thereof maintain good air permeability as an air filter medium while firmly bonding a base material, an ultrafine fiber, and a protective layer for protecting the substrate. Therefore, it is useful in filter applications and the like that are incorporated into an air conditioner, an air purifier, a water purifier, or the like and are used after pleating.

DESCRIPTION OF SYMBOLS 11 Air filter medium 12 Base material 13 Extra fine fiber layer 14 Protective layer 15 Adhesive material 16 Spray 17 Nozzle 101 Extra fine fiber layer 102 Heat-fusible fiber layer 103 Fibrous sheet 201 Fibre sheet 202 Extra fine fiber layer 203 Resin

Claims (13)

In an air filter medium having a base material, an ultrafine fiber layer composed of ultrafine fibers having a diameter of 100 nm to 1 μm, and a protective layer for protecting the ultrafine fiber layer, the ultrafine fiber is interposed between the base material and the protective layer. An air filter medium comprising a layer and an adhesive, wherein the adhesive penetrates a part of the ultrafine fiber layer and adheres the substrate and the protective layer. The air filter medium according to claim 1, wherein the base material is a sheet made of resin. The air filter medium according to claim 1, wherein the substrate is a sheet made of glass fiber. The air filter medium according to any one of claims 1 to 3, wherein the substrate is colored. The air filter medium according to any one of claims 1 to 4, wherein the protective layer is a sheet made of a resin fiber. In an air filter medium having a base material, an ultrafine fiber layer made of ultrafine fibers having a diameter of 100 nm to 1 μm, and a protective layer for protecting the ultrafine fiber layer, an adhesive layer made of an adhesive is provided on the surface of the base material. Providing the ultrafine fiber layer, and further stacking the protective layer, then pressing from both sides in the laminating direction, and bonding the base material and the protective layer with the adhesive, and the adhesive is the ultrafine A method for producing an air filter medium in which a part of a fiber layer is penetrated to adhere the substrate and the protective layer. After providing an adhesive layer with an adhesive on the surface of the base material, the ultrafine fiber layer is provided thereon, and further the protective layer is overlaid, and then crimped from both sides in the laminating direction, The method for producing an air filter medium according to claim 6, wherein the protective layer is adhered. The method for producing an air filter medium according to claim 6 or 7, wherein the adhesive layer is formed by spraying hot-melt powdery particles on the surface of the substrate. The method for producing an air filter medium according to any one of claims 6 to 8, wherein the base material is a sheet made of resin, and the base material and the protective layer are bonded while heating to melt the adhesive material. The method for producing an air filter medium according to claim 8 or 9, wherein the particle diameter of the adhesive is larger than the diameter of the ultrafine fibers. The method for producing an air filter medium according to any one of claims 8 to 10, wherein the adhesive has a particle size distribution, and a ratio of the small particle size to the large particle size is twice or more. The air filter according to claim 7, wherein the adhesive layer is formed by spraying a heat-meltable material on the surface of the substrate, an ultrafine fiber layer is provided thereon, and a protective layer is further stacked, and then these are heated and bonded. A method for producing a filter medium. The method for producing an air filter medium according to any one of claims 6 to 12, wherein the heating direction is from the substrate side.

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