Method for manufacturing fiber article

Abstract

The purpose of the present invention is to manufacture a fiber article that can be reduced in weight and improved in strength, and that can suppress an increase in pressure loss with the passage of use time, when manufacturing a fiber article comprising a first fiber and a second fiber having a smaller outer diameter than the first fiber. This method for producing a fibrous article comprises: a first step in which a plurality of resin pellets containing a fibrillar polymer are added to a fibrous sheet that contains a plurality of first fibers and is conveyed in a predetermined conveyance direction; a second step of applying a first external force to the plurality of first fibers and the plurality of resin granules of the conveyed fiber sheet so as to reduce the fiber gaps of the first fibers; and a third step of applying a second external force to the fiber sheet to which the applied first external force is relaxed and conveyed so as to enlarge fiber gaps between the plurality of first fibers in at least the width direction of the fiber sheet, thereby forming a plurality of second fibers thinner than the first fibers from the plurality of resin pellets, thereby forming a fiber composite containing a plurality of first fibers and a plurality of second fibers.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a manufacturing method of a fibrous article. BACKGROUND

[0002] In the present specification, each term defined below is used.

[0003] TD: total denier, which refers to the fiber size (grams per 9000 m) of a tow band or a bundle of a plurality of filaments.

[0004] FD: filament denier, which refers to the fiber size (grams per 9000 m) of a single fiber (one fiber). Also referred to as single fiber denier.

[0005] Tow band: a yarn that is a collection of filaments (single fibers) emitted from each spinneret of a plurality of spinning bobbins is combined, a plurality of yarns are combined and TD is set to a prescribed value to become an end portion. The end portion is crimped. The crimped end portion (collection of filaments) is referred to as a tow band. That is, the tow band has TD and a crimp number.

[0006] As a fibrous article for use as a filter or the like for an air conditioner, for example, as disclosed in Patent Literature 1, a manufacturing method of a fibrous article including a first fiber and a second fiber that is thinner in outer diameter than the first fiber is known.

[0007] PRIOR ART DOCUMENTS

[0008] PATENT LITERATURE

[0009] Patent Literature 1: International Publication No. 2021 / 039980 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] In the fibrous article described in Patent Literature 1, performance improvement of the fibrous article is sought by supporting the second fiber with the first fiber and exhibiting each function of the first fiber and the second fiber. Here, for example, if a fibrous article that can seek lightweight and strength improvement and can suppress an increase in pressure loss with the passage of use time can be manufactured, it is more preferable.

[0012] Therefore, an object of the present disclosure is to manufacture a fibrous article that can seek lightweight and strength improvement and can suppress an increase in pressure loss with the passage of use time in the case of manufacturing a fibrous article including a first fiber and a second fiber that is thinner in outer diameter than the first fiber.

[0013] SOLUTION TO PROBLEM

[0014] To solve the above problems, a manufacturing method of a fibrous article according to one aspect of the present disclosure includes: a first step of attaching a plurality of resin particles containing a high molecular weight polymer that can be fiberized to a fibrous sheet containing a plurality of first fibers and being conveyed in a prescribed conveying direction; a second step of applying a first external force to the plurality of first fibers and the plurality of resin particles of the fibrous sheet to which the plurality of resin particles are attached and which is being conveyed, to reduce fiber gaps of the first fibers; and a third step of applying a second external force to the fibrous sheet to which the first external force is relaxed and which is being conveyed in the conveying direction, to expand the fiber gaps of the plurality of first fibers in at least a width direction of the fibrous sheet, thereby forming a plurality of second fibers that are finer than the first fibers from the plurality of resin particles, to form a fibrous composite containing the plurality of first fibers and the plurality of second fibers.

[0015] Effects of the Invention

[0016] According to one aspect of the present disclosure, in the case of manufacturing a fibrous article containing first fibers and second fibers that are finer than the first fibers in outer diameter, a fibrous article that can seek weight reduction and strength improvement and can suppress an increase in pressure loss with the passage of use time can be manufactured. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic view of a fibrous sheet manufacturing apparatus of the first embodiment.

[0018] Figure 2 is a schematic view of a fibrous article manufacturing apparatus of the first embodiment.

[0019] Figure 3 is a schematic view of a fibrous article manufacturing apparatus of the second embodiment.

[0020] Figure 4 is a magnified photograph of a fibrous sheet before application of a second external force of Example 1.

[0021] Figure 5 is a magnified photograph of a fibrous sheet after application of a second external force of Example 1.

[0022] Figure 6 is a graph showing the relationship between the elongation in the width direction of the fibrous articles of Example 2 and Example 3 and the pressure loss.

[0023] Figure 7 is a graph showing the relationship between the elongation in the width direction of the fibrous articles of Example 2 and Example 3 and the trapping efficiency.

[0024] Figure 8 is a graph showing the relationship between the elongation in the width direction of the fibrous articles of Example 2 and Example 3 and the PF value.

[0025] Figure 9 is a graph showing the relationship between the elongation in the width direction and the thickness change rate of the fibrous article of Example 2 and Example 3.

[0026] Figure 10 is a graph showing the relationship between the elongation in the width direction and the weight per unit area of the fibrous article of Example 2 and Example 3.

[0027] Figure 11 is a graph showing the relationship between the elongation in the width direction and the pressure loss of the fibrous article of Example 4.

[0028] Figure 12 is a graph showing the relationship between the elongation in the width direction and the collection efficiency of the fibrous article of Example 4.

[0029] Figure 13 is a graph showing the relationship between the elongation in the width direction and the PF value of the fibrous article of Example 4.

[0030] Figure 14 is a graph showing the relationship between the elongation in the width direction and the weight per unit area of the fibrous article of Example 4.

[0031] Figure 15 is a graph showing the relationship between the elongation in the width direction and the thickness change rate of the fibrous article of Example 4.

[0032] Figure 16 is a graph showing the relationship between the J-ePM1 collection efficiency and the elongation of the fibrous article of Example 2 and Example 3.

[0033] Figure 17 is a graph showing the relationship between the J-ePM1 collection efficiency and the elongation of the fibrous article of Example 4. DETAILED DESCRIPTION

[0034] Hereinafter, each embodiment of the present disclosure will be described with reference to the accompanying drawings. Note that, in the present specification, in the case where only "collection efficiency" is referred to, it means the collection efficiency calculated by the following mathematical expression 3.

[0035] (FIRST EMBODIMENT)

[0036] The manufacturing method of the fibrous article of the first embodiment has the following first step to third step. In the first step, a plurality of resin particles containing a high molecular weight polymer capable of fiberization are attached to a fibrous sheet containing a plurality of first fibers and being transported in a prescribed transport direction. In the second step, a first external force is applied to the plurality of first fibers and the plurality of resin particles of the fibrous sheet to which the plurality of resin particles are attached and being transported, so as to reduce the fiber gap of the first fibers. In the third step, a second external force is applied to the fibrous sheet to which the first external force is relaxed and being transported in the transport direction, so as to expand the fiber gap of the plurality of first fibers in at least the width direction of the fibrous sheet, thereby forming a plurality of second fibers finer than the first fibers from the plurality of resin particles, and thereby forming a fibrous composite containing the plurality of first fibers and the plurality of second fibers. In the first step of the present embodiment, a nonwoven fabric is used as the fibrous sheet. In the present embodiment, in addition to the manufacturing method, a fibrous sheet manufacturing apparatus 1 and a fibrous article manufacturing apparatus 2 for the manufacturing method are described.

[0037] [Fibrous sheet manufacturing apparatus]

[0038] Figure 1 is a schematic diagram of a fibrous sheet manufacturing apparatus 1 (hereinafter, also referred to as manufacturing apparatus 1) of the first embodiment. As shown in Figure 1 , a package box B in which a veil-like raw material roll 50 containing a plurality of first fibers 51 as long fibers is folded and compressed and baled is supplied to the manufacturing apparatus 1. The manufacturing apparatus 1 continuously draws out the raw material roll 50 from the package box B. The manufacturing apparatus 1 manufactures a fibrous sheet 60 from a plurality of short fibers 52 formed of the plurality of first fibers 51. The manufacturing apparatus 1 of the present embodiment functions as a nonwoven fabric manufacturing apparatus. The fibrous sheet 60 of the present embodiment is a nonwoven fabric. The nonwoven fabric referred to in the present specification means a nonwoven fabric according to JIS L 0222:2001. As one example, in the present embodiment, the fibrous sheet 60 as a nonwoven fabric is manufactured based on a needle punching method. The manufacturing method of the nonwoven fabric is not limited to the needle punching method, and can be other known methods such as a hydroentangling method. The fibrous sheet 60 is transported in a prescribed transport direction P. The fibrous sheet 60 is a long strip in which the transport direction P is set as a long dimension direction and a direction orthogonal to the transport direction P in a direction perpendicular to a thickness direction is set as a width direction. Note that the transport direction P is also referred to as an MD direction. Further, the direction orthogonal to the transport direction P is also referred to as a TD direction.

[0039] The material of the first fibers 51 can be appropriately selected. As one example, the first fibers 51 include at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, and cellulose acetate. Further, as one example, the first fibers 51 are crimped. With this, the blank roll 50 has stretchability. The blank roll 50 drawn out from the packaging box B is interwoven with a plurality of the first fibers 51. The blank roll 50 of the present embodiment is a tape bundle including crimped cellulose acetate fibers (hereinafter, also referred to as CA fibers) as the first fibers 51. As one example, the CA fibers are spun by a dry spinning method. The spinning method is not limited to the dry spinning method. The CA fibers are crimped by primary crimping as the smallest crimping unit, and are crimped by secondary crimping as a crimping unit larger than the primary crimping. The CA fibers can also be crimped by higher-order crimping as a crimping unit larger than the secondary crimping. The cross-sectional shape of the first fibers 51 can be appropriately set. The cross-sectional shape of the first fibers 51 can be set to, for example, any one of a circular shape, a Y-shape, and an irregular shape.

[0040] The TD and the FD of the blank roll 50 can be appropriately set. As one example, the TD of the blank roll 50 is a value of several million units, several hundred thousand units, several ten thousand units, or several thousand units. In another example, the TD of the blank roll 50 is preferably a value in a range of 3 million or more and 5 million or less, more preferably a value in a range of 1 million or more and 2 million or less. Further, in another example, the TD of the blank roll 50 is preferably a value in a range of 1 million or more and 7 million or less, more preferably a value in a range of 1 million or more and 3 million or less. Further, in another example, the TD of the blank roll 50 is preferably a value in a range of 5 thousand or more and 1 million or less, more preferably a value in a range of 10 thousand or more and 50 thousand or less.

[0041] As one example, the FD of the blank roll 50 is a value in a range of 20 or less. In another example, the FD of the blank roll 50 is preferably a value in a range of 1 or more and 15 or less, more preferably a value of 1 or more and 10 or less, further preferably a value in a range of 1 or more and 8 or less. At the time of driving of the manufacturing apparatus 1 of the present embodiment, the blank roll 50 is transported while being applied with a weak tension (load) in a range of a value of 2 mgf or more and 50 mgf or less per 1 denier.

[0042] As a specific example, the manufacturing apparatus 1 includes: a pair of feed rollers 3 and a plurality of guide members G1 to G3 that guide the blank roll 50 drawn out from the package box B; and a cutter 10 that forms a plurality of staple fibers 52 from the plurality of first fibers 51 of the blank roll 50. The pair of feed rollers 3 has a pair of feed rollers 4, 5. As one example, the guide members G1 to G3 include a plurality of guide rollers. Further, the manufacturing apparatus 1 includes: a conveyance apparatus 11 that conveys the plurality of staple fibers 52 discharged from the cutter 10; and a baling apparatus 12 that compressively bales the plurality of staple fibers 52 conveyed by the conveyance apparatus 11. The baling apparatus 12 forms a fiber block 53 that compressively bales the plurality of staple fibers 52 into a prescribed shape. The fiber block 53 is used in the next process. Note that the pair of feed rollers 3 is not essential, and thus can be omitted.

[0043] Further, the manufacturing apparatus 1 includes: an opener 13 that refines the plurality of staple fibers 52 in the fiber block 53 by removing impurities; a blower BL that conveys the plurality of staple fibers 52 that have passed through the opener 13 in a conveyance direction P; a metering feeder 14 that meters the plurality of staple fibers 52 conveyed by the blower BL and supplies the plurality of staple fibers 52 to a carding machine 15 in a prescribed amount each time; and at least one carding machine 15 that performs a carding process on the plurality of staple fibers 52. The carding machine 15 forms a nonwoven fabric intermediate 54 that contains the plurality of staple fibers 52.

[0044] The length dimension of the staple fiber 52 can be appropriately set. As one example, the length dimension of the staple fiber 52 is a value in a range of 10 mm or more and 100 mm or less. In another example, the length dimension of the staple fiber 52 is a value in a range of 30 mm or more and 100 mm or less. For example, in a case where the length dimension of the staple fiber 52 is a value of 100 mm or less, unnecessary entanglement of the staple fiber 52 to the carding machine 15 can be suppressed. Further, for example, in a case where the length dimension of the staple fiber 52 is a value of 10 mm or more, the plurality of staple fibers 52 that are crimped can be easily entangled with each other. Thus, a nonwoven fabric, that is, a fiber sheet 60 that is rich in fiber gaps and fluffy can be obtained. Further, a fiber article 62 in which the fiber density is reduced can be obtained compared to a case where the plurality of staple fibers that are not crimped are used (see FIG. 6). Figure 2 ).

[0045] Further, the manufacturing apparatus 1 includes: an interlacer 19 that interlaces the plurality of staple fibers 52 of the nonwoven fabric intermediate 54 discharged from the carding machine 15 to form the fiber sheet 60 that is a nonwoven fabric; a dryer 20 that dries the fiber sheet 60 discharged from the interlacer 19; and a winder 21 that winds the fiber sheet 60 that has passed through the dryer 20. As one example, the interlacer 19 has a plurality of needles that interlace the plurality of staple fibers 52 in the nonwoven fabric intermediate 54 by reciprocating in a prescribed direction.

[0046] Further, the manufacturing apparatus 1 is provided with a supply apparatus 18. The supply apparatus 18 supplies a second intermediate body 59, which is a nonwoven fabric intermediate body containing a plurality of fibers, to the first intermediate body 56, which is a nonwoven fabric intermediate body discharged from the carding machine 15. The second intermediate body 59 contains short fibers 52 or fibers different from the short fibers 52. As one example, the second intermediate body 59 contains, for example, pulp fibers or synthetic fibers. The second intermediate body 59 is drawn out from a supply roller R1 possessed by the supply apparatus 18 and is arranged so as to overlap the first intermediate body 56. The intermediate bodies 56, 59 are transported in a state of overlapping each other and are introduced into the interlacer 19. The interlacer 19 interlaces the plurality of fibers of the intermediate bodies 56, 59. Thus, a fiber sheet 60, which is a composite sheet of the intermediate bodies 56, 59 arranged so as to overlap each other and which is a nonwoven fabric, is formed.

[0047] Note that the fiber sheet 60 can also contain a plurality of first intermediate bodies 56 and at least one second intermediate body 59. In this case, the second intermediate body 59 can also be arranged between the plurality of first intermediate bodies 56. Further, the second intermediate body 59 can also be further arranged so as to overlap a laminate containing the plurality of first intermediate bodies 56. Further, the plurality of first intermediate bodies 56 and at least one second intermediate body 59 can also be interlaced integrally. Further, the manufacturing apparatus 1 can also omit the supply apparatus 18. In this case, the fiber sheet 60 is composed only of the first intermediate body 56.

[0048] The fiber sheet 60 discharged from the interlacer 19 is dried by the dryer 20. The dried fiber sheet 60 is wound on a winding roller R2 possessed by the winder 21. The winding roller R2 is used for the next process.

[0049] [Manufacturing apparatus of fiber article]

[0050] Figure 2 is a schematic view of a manufacturing apparatus 2 of a fiber article according to a first embodiment (hereinafter, also referred to as the manufacturing apparatus 2). In Figure 2 , an enlarged view of a first fiber 51 (short fiber 52), a resin particulate 91, and a second fiber 92 contained in a fiber composite 61 and a fiber article 62 manufactured is also shown. The fiber sheet 60 containing a plurality of the first fibers 51 (short fibers 52 in this case) is supplied to the manufacturing apparatus 2 from a winding roller R2. As described in detail later, in the manufacturing apparatus 2 of the present embodiment, a prescribed first external force and a second external force are applied to the fiber sheet 60 to which a plurality of the resin particulates 91 are attached and which is transported, whereby the second fibers 92 are formed from the resin particulates 91. Thus, the fiber composite 61 containing the first fibers 51 and the second fibers 92 is formed.

[0051] As a specific example, the manufacturing apparatus 2 includes a plurality of guide members G4 to G7 that guide the fibrous sheet 60 in the conveyance direction P, an applicator 25 that applies the application liquid 90 containing a plurality of resin particulates 91 to the fibrous sheet 60, and a dryer 26 that dries the fibrous sheet 60 to which the application liquid 90 is applied. As one example, the guide members G4 to G7 include a plurality of guide rollers. Further, the manufacturing apparatus 2 includes a press roller pair 27 that press-bonds the fibrous sheet 60 after drying, and an extension apparatus 30 that extends the plurality of first fibers 51 (short fibers 52) included in the fibrous sheet 60 that has passed through the press roller pair 27 in a prescribed direction. The press roller pair 27 has a pair of press rollers 28, 29. Further, the manufacturing apparatus 2 includes a winding machine 31 that winds the fibrous composite 61 that is discharged from the extension apparatus 30.

[0052] As one example, the applicator 25 has a storage portion 32 that stores the application liquid 90, and an application roller 33 that applies the application liquid 90 in the storage portion 32 to the short fibers 52 (first fibers 51) of the fibrous sheet 60 via the peripheral surface thereof. Further, the applicator 25 has a liquid collection portion 34 that collects the application liquid 90 discharged from the storage portion 32, and a pump 35 that recirculates the collected application liquid 90 to the storage portion 32. Note that the configuration of the applicator 25 is not limited thereto. For example, the applicator 25 can also have one or more nozzles that spray the application liquid 90 to the fibrous sheet 60, and a housing that houses the nozzles. As one example, the application liquid 90 is a water application liquid. By using a water application liquid, the application liquid 90 can be manufactured more inexpensively. Further, the application liquid 90 can be easily disposed of. The application liquid 90 can also contain a liquid other than water.

[0053] As one example, the resin particulate 91 has a structure in which high molecular chains are connected and folded, that is, a lamellar structure. The lamellar structure is specifically composed of fine fibers that are formed in a ribbon shape by the high molecular chains being connected in units of several million. The fine fibers are folded and housed inside the resin particulate 91.

[0054] The resin particulate 91 is a primary particle. A secondary particle is formed by a plurality of resin particulates 91 being combined with each other. If an external force is applied to two combined resin particulates 91 in a direction in which they are separated from each other, the fine fibers of the resin particulate 91 are pulled out to the outside to form a second fiber 92. When the application liquid 90 is applied to the first fiber 51, a plurality of resin particulates 91 are dispersed and applied to the surface of the plurality of first fibers 51. As one example, the secondary particle of the plurality of resin particulates 91 is applied to the surface of the first fiber 51.

[0055] The resin particles 91 are, for example, generated only by a polymerization reaction and have a lamellar structure. As one example, the resin particles 91 contain at least one of PTFE (polytetrafluoroethylene), polypropylene, polyethylene, and polyamide. The resin particles 91 of the present embodiment contain PTFE.

[0056] As one example, the PTFE contained in the resin particles 91 is high-molecular-weight PTFE obtained by emulsion polymerization or suspension polymerization of TFE. The high-molecular-weight PTFE can be at least one of modified PTFE and homopolymer PTFE. The modified PTFE contains, for example, a monomer other than TFE such as a modifying monomer. In general, the modified PTFE is uniformly modified by the modifying monomer and is modified at the initial stage or the final stage of the polymerization reaction, but is not particularly limited. The modified PTFE contains a TFE unit based on TFE and a modifying monomer unit based on the modifying monomer. The "modifying monomer unit" in the present specification refers to a portion of the molecular structure of the modified PTFE and is a portion derived from the modifying monomer. The modifying monomer is not particularly limited as long as it can be copolymerized with TFE.

[0057] Furthermore, the "high-molecular-weight" of the high-molecular-weight PTFE in the present specification refers to a molecular weight that is easily fiberized at the time of manufacturing the fiber article 62, can obtain a fibril having a long fiber length, and is a value in a range of 2.130 or more and 2.230 or less in terms of standard specific gravity (SSG), and is a molecular weight that is substantially not melt-flowed due to a high melt viscosity. Note that, for the PTFE that can be fiberized, for example, refer to the description of International Publication No. 2013 / 157647.

[0058] As one example, the average particle diameter of the resin particles 91 is set to a value in a range of 100 nm or more and 100 pm or less. As one example, the average particle diameter is more preferably a value in a range of 200 nm or more and 700 nm or less, and is further preferably a value in a range of 250 nm or more and 400 nm or less. Note that, in the present specification, the average particle diameter refers to a median diameter (cumulative 50% diameter (D50)) calculated from a measurement result based on a dynamic light scattering method. As one example, the resin particles 91 are molded by paste extrusion molding.

[0059] The pair of press rolls 27 applies a first external force to the plurality of first fibers 51 and the plurality of resin particulates 91 in the fibrous sheet 60 to which the plurality of resin particulates 91 are attached and which is being conveyed, so as to reduce the fiber gaps of the first fibers 51. As one example, the pair of press rolls 27 of the present embodiment is a pair of heat press rolls that heat-presses the fibrous sheet 60. The heating temperature at which the plurality of first fibers 51 and the plurality of resin particulates 91 are heated by the pair of heat press rolls can be appropriately adjusted. As one example, the heating temperature can be set to a temperature in a range higher than 25°C and lower than 200°C. The heating temperature is, for example, preferably a temperature in a range of 50°C or higher and 200°C or lower, more preferably a temperature in a range of 70°C or higher and 200°C or lower, and further preferably a temperature in a range of 90°C or higher and 200°C or lower. Further, in another example, the heating temperature is preferably a temperature in a range of 110°C or higher and 200°C or lower, and further preferably a temperature in a range of 150°C or higher and 200°C or lower. The heating temperature can be, for example, also lower than the melting point of each of the materials of the first fibers 51 and the resin particulates 91, or lower than the decomposition temperature of each of the materials.

[0060] The stretching device 30 applies a second external force to the fibrous sheet 60 to which the first external force is relaxed and which is being conveyed, so as to expand the fiber gaps of the plurality of first fibers 51 in at least the width direction W (a direction perpendicular to the plane of the paper in the present embodiment) of the fibrous sheet 60. As one example, the stretching device 30 of the present embodiment applies the second external force to the fibrous sheet 60 being conveyed in the conveyance direction P and the width direction W. As one example, the stretching device 30 is a publicly known simultaneous biaxial stretching device. For the configuration of the simultaneous biaxial stretching device, for example, refer to the description of Japanese Patent No. 4224241. Figure 2

[0061] When the manufacturing device 2 is driven, the fibrous sheet 60 to which the attaching liquid 90 is attached by the attacher 25 is fed to the drying machine 26. In the fibrous sheet 60, the solvent component of the attaching liquid 90 is volatilized to perform drying. The fibrous sheet 60 after drying is introduced to the pair of press rolls 27. When the fibrous sheet 60 passes through the nip of the pair of press rolls 27, a first external force is applied to the plurality of first fibers 51 and the plurality of resin particulates 91 of the fibrous sheet 60. Further, in the present embodiment, the plurality of first fibers 51 and the plurality of resin particulates 91 are heated by the pair of press rolls 27 when the first external force is applied. The first fibers 51 are plasticized by being heated. Thus, the fiber gaps are easily reduced by the first external force. The fibrous sheet 60 passes through the nip of the pair of press rolls 27, whereby the first external force applied to the plurality of first fibers 51 and the plurality of resin particulates 91 is relaxed.

[0062] ​Note that the first external force can be applied to the plurality of first fibers 51 and the plurality of resin particulates 91 by a pair of press rollers other than the pair of press rollers. Also, the first external force can be applied to the plurality of first fibers 51 and the plurality of resin particulates 91 by a structure other than the pair of press rollers. In this case, for example, the manufacturing apparatus 2 can be provided with a pair of press rollers that does not have a heating function.

[0063] The fiber sheet 60 whose first external force is relaxed is introduced into the extending apparatus 30. In the extending apparatus 30, the fiber sheet 60 is applied with a second external force to expand the fiber gaps of the plurality of first fibers 51 in the conveyance direction P and the width direction W. At this time, the second external force is applied to the plurality of first fibers 51 and the plurality of resin particulates 91 in a manner to pull apart the resin particulates 91 that are adhered to each other between the plurality of first fibers 51. Thus, the fine fibers of the resin particulates 91 are stretched to the outside to form the second fibers 92 in a manner to bridge the different plurality of first fibers 51 to each other. As a result, the fiber composite 61 containing the plurality of first fibers 51 and the abundant plurality of second fibers 92 is formed. Here, the second fibers 92 of the present embodiment contain PTFE as a main component. In other words, the second fibers 92 contain more than 50% by weight of PTFE of the total weight of the second fibers 92. The plurality of second fibers 92 are fixed to the plurality of first fibers 51 in a state of being dispersed from each other. Therefore, according to the present embodiment, it is possible to manufacture the fiber article 62 whose mesh structure constituted by the plurality of first fibers 51 and the plurality of second fibers 92 is less likely to be damaged and whose strength is improved.

[0064] Here, the second fibers 92 are also formed by expanding the fiber gaps of the plurality of first fibers 51 by relaxing the first external force applied to the fiber sheet 60. However, in the present embodiment, the fiber gaps of the plurality of first fibers 51 are expanded in a desired direction by actively applying the second external force to the plurality of first fibers 51 and the plurality of resin particulates 91. Thus, it is possible to form more abundant second fibers 92. Also, for example, by adjusting at least either one of the strength of the second external force and the temperature at the time of applying the second external force, it is possible to adjust the thickness or the number of the second fibers 92 formed, and the like. Thus, it is possible to adjust the respective characteristics of the fiber article 62 to be manufactured within a certain range.

[0065] Further, in the fiber sheet 60 of the present embodiment, the fiber gaps of the plurality of first fibers 51 in the thickness direction are naturally enlarged by the restoring force after the first external force applied to the plurality of first fibers 51 and the plurality of resin particulates 91 is relaxed. In contrast, in the fiber sheet 60, the fiber gaps in both the conveyance direction P and the width direction W of the plurality of first fibers 51 are enlarged by the application of the second external force. Thus, as one example, the fiber sheet 60 is formed so that the fiber gaps in the two directions perpendicular to the thickness direction and orthogonal to each other are wider than the fiber gap in the thickness direction. The "fiber gaps in the two directions" mentioned here correspond to the conveyance direction P and the width direction W.

[0066] The fiber composite 61 is wound around a winding roller R3 provided in the winding machine 31. The fiber article 62 is manufactured by cutting the fiber composite 61 into a predetermined size. Thus, the fiber article 62 in which the deviation of the fiber gaps between the plurality of first fibers 51 and the plurality of second fibers 92 in the fiber gaps in the two directions is suppressed is manufactured. The fiber article 62 of the present embodiment has a configuration in which the fiber gaps in the two directions are formed to be wider than the fiber gap in the thickness direction. Thus, for example, a fiber article 62 having a small weight per unit area and in which the pressure loss is suppressed from increasing with the passage of time is manufactured.

[0067] As one example, the fiber article 62 manufactured by the manufacturing method of the present embodiment is a filter member that is arranged in a flow path through which a predetermined fluid flows and filters impurities mixed into the fluid. The fluid inside the fiber article 62 can also be either of a gas and a liquid. As one example, the gas is air. The fiber article 62 is in a sheet shape. As shown in the enlarged view in FIG. 6, in the manufactured fiber article 62, a plurality of resin particulates 91 are sometimes left, for example. Figure 2

[0068] As such, the manufacturing method of the fiber article 62 of the present embodiment has a first step in which the fiber sheet 60 containing the plurality of first fibers 51 and being conveyed in a predetermined conveyance direction P is attached with the plurality of resin particulates 91 containing a fiberizable high molecule. Further, there is a second step in which the plurality of first fibers 51 and the plurality of resin particulates 91 in the fiber sheet 60 to which the plurality of resin particulates 91 are attached and which is being conveyed are subjected to the first external force so that the fiber gaps of the first fibers 51 are reduced.

[0069] ​Further, the manufacturing method has a third step in which a second external force is applied to the fiber sheet 60, which has been transported after the first external force has been relaxed after being applied, to expand the fiber gaps of the plurality of first fibers 51 in at least the width direction W of the fiber sheet 60, thereby forming second fibers 92 having a smaller outer diameter than the first fibers 51 from the plurality of resin granules 91, and forming a fiber composite 61 containing the first fibers 51 and the second fibers 92.

[0070] Further, in the third step of the present embodiment, as one example, the second external force is applied to the fiber sheet 60 in a plurality of directions including the width direction W. Further, as one example, in the third step, the second external force is simultaneously applied to the fiber sheet 60 in a plurality of directions including the width direction W.

[0071] Further, for example, by adjusting at least either one of the strength of the second external force and the temperature at the time of applying the second external force, it is possible to adjust the fiber gaps of the plurality of first fibers 51 and the plurality of second fibers 92, the number of the second fibers 92, and the length dimension of the second fibers 92 of the fiber article 62. Thus, it is possible to manufacture fiber articles 62 having different characteristics. Specifically, by increasing the second external force within a certain range, the weight per unit area and the thickness in a natural state of the fiber article 62 decrease. Further, by decreasing the second external force within a certain range, the weight per unit area and the thickness in a natural state of the fiber article 62 increase. Further, by increasing the second external force within a certain range, abundant second fibers 92 are formed. Further, for example, if the number of the second fibers 92 increases, the tensile elongation of the fiber article 62 with respect to a natural state decreases. Further, for example, if the number of the second fibers 92 increases, the tensile strength of the fiber article 62 increases.

[0072] Further, for example, by adjusting at least either one of the strength of the second external force and the temperature at the time of applying the second external force, it is possible to adjust the outer diameter D2 of the second fibers 92. By increasing the second external force within a certain range, it is possible to set the outer diameter D2 to be small. Further, by decreasing the second external force within a certain range, it is possible to set the outer diameter D2 to be large.

[0073] In the production method of the present embodiment, the outer diameter D2 of the second fiber 92 is set to be finer than the outer diameter Dl of the first fiber 51. Therefore, the manufactured fiber article 62 has a hetero-diameter fiber composite structure. As one example, by adjusting at least either one of the strength of the second external force and the temperature at the time of applying the second external force, the ratio Dl / D2 of the outer diameter Dl to the outer diameter D2 can be set to a value in a range of 15.0 or more and 1666.7 or less. As the ratio Dl / D2, for example, a value in a range of 15.0 or more and 1300.0 or less is preferred, a value in a range of 15.0 or more and 714.3 or less is more preferred, and a value in a range of 15.0 or more and 300.0 or less is further preferred. Further, in another example, as the ratio Dl / D2, for example, a value in a range of 60.0 or more and 1666.7 or less is preferred, a value in a range of 60.0 or more and 1300.0 or less is more preferred, a value in a range of 60.0 or more and 714.3 or less is further preferred, and a value in a range of 60.0 or more and 300.0 or less is yet further preferred.

[0074] If the ratio Dl / D2 is 15.0 or more, for example, a fiber article 62 in which the respective functions of the first fiber 51 and the second fiber 92 having different outer diameters are easily embodied can be manufactured. Further, if the value of the ratio Dl / D2 is 1666.7 or less, for example, a fiber article 62 in which the increase in the outer diameter Dl of the first fiber 51 is suppressed and the second fiber 92 is easily spread around the first fiber 51 can be manufactured. Further, by maintaining the outer diameter D2 to a value to some extent large, the second fiber 92 can be easily formed. Further, by setting the ratio Dl / D2 to a value in a range of 60.0 or more and 1666.7 or less, the filtration performance of the manufactured fiber article 62 can be maintained, and the use amount of the second fiber 92 can be reduced to suppress the production cost of the fiber article 62.

[0075] Further, as the outer diameter Dl, for example, a value in a range of 5.0 μm or more and 50.0 μm or less is preferred, and a value in a range of 20.0 μm or more and 30.0 μm or less is more preferred. Thereby, the second fiber 92 can be stably supported by the first fiber 51, and a plurality of second fibers 92 can be easily arranged around the first fiber 51.

[0076] Further, as the outer diameter D2, for example, a value in the range of 30.0 nm or more and 1.0 μm or less is preferred, a value in the range of 30.0 nm or more and 800 nm or less is more preferred, and a value in the range of 30.0 nm or more and 166.7 nm or less is further preferred. Further, in another example, as the outer diameter D2, for example, a value in the range of 50.0 nm or more and 800.0 nm or less is preferred. Thereby, the outer diameter D2 of the second fiber 92 can be prevented from being excessively thin, and the ratio D1 / D2 can be increased. As a result, the fiber article 62 in which a plurality of second fibers 92 are abundantly contained can be stably manufactured.

[0077] Further, as one example, in the fiber article 62 manufactured by the manufacturing method of the present embodiment, the ratio V1 / V2 of the total volume V1 of the first fiber 51 to the total volume V2 of the second fiber 92 and the resin particulate 91 combined is set to a value in the range of 1.9 or more and 124.0 or less. Desirably, the ratio V1 / V2 is further set to a value in the range of 20.0 or more and 124.0 or less. Thereby, the fiber article 62 in which the outer diameter D1 of the first fiber 51 and the outer diameter D2 of the second fiber 92 are different and the respective functions of the first fiber 51 and the second fiber 92 are easily embodied can be manufactured.

[0078] Further, in the third step of the present embodiment, as one example, the fiber sheet 60 is subjected to the second external force in a manner such that the unit area weight is in the range of 60 g / m 2 and 300 g / m 2 and the tensile strength in the strength minimum direction in which the tensile strength in the direction perpendicular to the thickness direction is the smallest is a value in the range of 0.8 N / 10 mm or more and 100 N / 10 mm or less. The unit "N / 10 mm" indicates how much load in N per 10 mm of measurement width can be borne. The "strength minimum direction" herein corresponds to the width direction W of the fiber sheet 60. The tensile strength in the strength minimum direction can be adjusted, for example, by the second external force applied to the fiber sheet 60 being transported in the width direction W. Thereby, the fiber article 62 in which the unit area weight and the tensile strength in the strength minimum direction are set to values in the respective ranges described above can be manufactured.

[0079] In this embodiment, generally, for example, in the case where the fibrous sheet material is continuously manufactured by a wet papermaking method, a plurality of short fibers contained in the additive liquid as the fibrous sheet material are oriented in a manner extending in a conveyance direction of the fibrous sheet in the production line. Further, for example, in the case where a plurality of first fibers included in the fibrous sheet are continuously spun by a dry spinning method, the first fibers of the long fibers discharged from the spinning drum are oriented in a manner extending in the conveyance direction. Thus, the conventional fibrous article has a constitution in which a plurality of fibers extend in a direction orthogonal to a direction of minimum strength (in other words, a direction corresponding to the conveyance direction of the fibrous sheet in the production line. Hereinafter, also referred to as "second direction") in a direction perpendicular to a thickness direction. In the conventional fibrous article, entanglement of a plurality of fibers in the direction of minimum strength is less. Thus, among a plurality of directions perpendicular to the thickness direction, the strength of the fibrous article is minimum in the direction of minimum strength.

[0080] In contrast, the fibrous article 62 of the present embodiment is formed in a manner in which the abundant second fibers 92 extend in the width direction W of the fibrous sheet at the time of manufacture. Thereby, entanglement of the first fibers 51 and the second fibers 92 of the fibrous article 62 in the direction of minimum strength is increased. As a result, the tensile strength in the direction of minimum strength of the fibrous article 62 is set to a value in a range of at least 0.8 N / 10 mm or more due to the abundant first fibers 51 and the second fibers 92.

[0081] Further, the tensile strength in the direction of minimum strength of the fibrous article 62 is a value in a range of 100 N / 10 mm or less. Thereby, for example, it is possible to prevent the tensile strength of the fibrous article 62 from being excessively increased and easily manufacture the fibrous article 62. The tensile strength in the direction of minimum strength of the fibrous article 62 of the present embodiment is a value in a range of 0.8 N / 10 mm or more and 100 N / 10 mm or less. As the range of the tensile strength in the direction of minimum strength, for example, it is preferable that a value in a range of 1 N / 10 mm or more and 100 N / 10 mm or less, and further preferable that a value in a range of 5 N / 10 mm or more and 100 N / 10 mm or less. Further, in another example, as the range of the tensile strength in the direction of minimum strength, for example, it is preferable that a value in a range of 8 N / 10 mm or more and 100 N / 10 mm or less, and further preferable that a value in a range of 10 N / 10 mm or more and 100 N / 10 mm or less.

[0082] The value of the weight per unit area set by the third step is, for example, preferably a value in a range of 60 g / m 2 and 300 g / m 2 and 250 g / m 2 and 250 g / m 2 and 250 g / m Further, in another example, the value of the weight per unit area is, for example, preferably a value in a range of 60 g / m2 above and 200 g / m 2 the following range of values, more preferably 80 g / m 2 above and 200 g / m 2 the following range of values, further preferably 100 g / m 2 above and 200 g / m 2 the following range of values. Thereby, the lightweight of the fibrous article 62 can be easily pursued.

[0083] Further, in the third step of the present embodiment, as one example, the second external force is applied to the fibrous sheet 60 in a manner that the fiber composite 61 is formed in a range of values of 5% or more and 250% or less of the tensile elongation with respect to the natural state in the direction of the minimum strength. Thereby, the fibrous article 62 in which the tensile elongation is set to the range of values can be manufactured. As the tensile elongation, for example, a range of values of 10% or more and 250% or less is preferable, and a range of values of 20% or more and 250% or less is further preferable. Further, in another example, as the tensile elongation, for example, a range of values of 30% or more and 250% or less is preferable, and a range of values of 40% or more and 250% or less is further preferable.

[0084] Here, the tensile strength is measured using a TENSILON universal material testing machine as a tensile testing machine in accordance with JIS B 7721:2018, for example. In this case, a test piece shaped in a width of 10 mm and a length of 60 mm is used. Further, the tensile strength is measured under the setting conditions of a chuck-to-chuck distance of 40 mm and a tensile speed of 200 mm / min. Further, the tensile elongation is calculated based on the following Equation 1 under the same conditions as the measurement of the tensile strength.

[0085] [Equation 1]

[0086] Tensile Elongation (%) = Elongation (mm) / Chucks-to-Chuck Distance (mm) x 100

[0087] Further, in the third step of the present embodiment, as one example, a second external force is applied to the fibrous sheet 60 in a manner to form a fibrous composite 61 having a PF value in a range of 16 or more and 84 or less. The PF value in the present specification refers to a value calculated based on the following Equation 2, Equation 3, and Equation 4. In calculating the transmittance (%) described in Equation 2, NaCl particles having a particle diameter of 0.4 μm are generated using a method described in JIS B9928: 1998 Appendix 5 (Regulation) Method for generating NaCl aerosol (pressurized spray method). The number of NaCl particles before and after the air containing the NaCl particles is passed through the fibrous article 62 in the thickness direction at a flow rate of 5.3 cm / sec is measured by a particle counter. The transmittance (%) is calculated based on the measured value.

[0088] [Equation 2]

[0089] Transmittance (%) = (CO / CI) x 100

[0090] where CO is the number of NaCl particles after the fibrous article 62 is passed. CI is the number of NaCl particles before the fibrous article 62 is passed.

[0091] [Equation 3]

[0092] Collection efficiency (%) = 100 - transmittance (%)

[0093] [Equation 4]

[0094] PF value = {-log(100 - collection efficiency (%)) / 100} / (pressure loss (Pa) / 1000)

[0095] As the PF value, for example, a value in a range of 16 or more and 70 or less is preferred, and a value in a range of 16 or more and 60 or less is further preferred. Further, in another example, for example, a value in a range of 20 or more and 84 or less is preferred, and a value in a range of 25 or more and 84 or less is further preferred.

[0096] Further, in the third step of the present embodiment, as one example, the second external force is applied to the fibrous sheet 60 in a manner to form the fibrous composite 61 having a value in the range of less than 3.0 mm in thickness in the natural state. Thereby, the fibrous article 62 having a value in the range of less than 3.0 mm in thickness in the natural state is produced. Therefore, the fibrous article 62 which is easy to be compactified can be produced. The thickness in the natural state of the fibrous composite 61 set by the third step is, for example, preferably a value in the range of 0.1 mm or more and less than 3.0 mm, more preferably a value in the range of 0.1 mm or more and 2.5 mm or less, and further preferably a value in the range of 0.1 mm or more and 2.0 mm or less. Further, in another example, the thickness is, for example, preferably a value in the range of 0.5 mm or more and 2.5 mm or less, and further preferably a value in the range of 1.0 mm or more and 2.5 mm or less.

[0097] Further, in the third step of the present embodiment, as one example, the second external force is applied to the fibrous sheet 60 in a manner to form the fibrous composite 61 having a value in the range of 3 Pa or more and 35 Pa or less in pressure loss when air passes at a flow rate of 5.3 cm / sec in the thickness direction. Thereby, the fibrous article 62 having a value in the range of the pressure loss can be produced. The pressure loss of the fibrous composite 61 set by the third step is, for example, preferably a value in the range of 3 Pa or more and 25 Pa or less, and further preferably a value in the range of 3 Pa or more and 15 Pa or less. Further, in another example, the pressure loss is, for example, preferably a value in the range of 6 Pa or more and 35 Pa or less, and further preferably a value in the range of 9 Pa or more and 35 Pa or less.

[0098] The pressure loss is measured, for example, by the following procedure. A measurement sample is set in a holder having an inner diameter of 113 mm (effective area of the filter material: 100 cm 2 The flow rate of air flowing through the measurement sample is adjusted to 5.3 cm / sec by a flow meter. The pressure loss generated at this time between the upstream side and the downstream side of the flow direction of air of the measurement sample is measured by a pressure gauge.

[0099] Further, in the third step of the present embodiment, as one example, the second external force is applied to the fibrous sheet 60 in a manner to form the fibrous composite 61 having a value in a range of 35% or more and 95% or less of the collection efficiency. The collection efficiency is calculated by Equation 3. Thereby, the fibrous article 62 having the collection efficiency set to the range can be manufactured. As the collection efficiency set by the third step, for example, a value in a range of 35% or more and 85% or less is preferable, and a value in a range of 35% or more and 75% or less is further preferable. Further, in another example, as the collection efficiency, for example, a value in a range of 40% or more and 90% or less is preferable, and a value in a range of 45% or more and 90% or less is further preferable.

[0100] Note that, in a case where at least any one of the unit area weight, the tensile strength, the tensile elongation, the PF value, the thickness in the natural state, the pressure loss, and the collection efficiency of the fibrous composite 61 is set, for example, by using a single first intermediate body 56, it is possible to easily set to a desired set value.

[0101] Further, in the third step of the present embodiment, the second external force is applied to the fibrous sheet 60 in a manner to form the fibrous composite 61 that is classified into a filter group of JIS-ePM1 in the classification described in item 7.3 of JIS B 9908-1:2019. Thereby, it is possible to manufacture the fibrous article 62 that can be used for a high-quality filter of the filter group classified as “JIS-ePM1”.

[0102] As described above, according to the manufacturing method of the fibrous article 62 of the present embodiment, in a case where the fibrous article 62 including the first fiber 51 and the second fiber 92 thinner than the first fiber 51 in the outer diameter is manufactured, it is possible to manufacture the fibrous article 62 that can seek weight reduction and strength improvement and can suppress an increase in the pressure loss with the passage of time. Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment.

[0103] (Second Embodiment)

[0104] Figure 3 is a schematic view of a fibrous article manufacturing apparatus 102 (hereinafter, also referred to as a manufacturing apparatus 102) of the second embodiment. The manufacturing apparatus 102 differs from the manufacturing apparatus 2 in that it is provided with a publicly known sequential biaxial stretching apparatus. The manufacturing apparatus 102 is provided with a first stretching apparatus 87 configured of the following constituent elements 65 to 69 and stretching the fibrous sheet 60 in the conveyance direction (the longitudinal direction) P. Further, the manufacturing apparatus 102 is provided with a second stretching apparatus 88 configured of the following constituent elements 82 to 83 and stretching the fibrous sheet 60 in the width direction (the lateral direction) W. The fibrous sheet 60 having the first fiber 51 and the second fiber 92 wound thereon is supplied to the manufacturing apparatus 102. The fibrous sheet 60 is stretched in the conveyance direction P by the first stretching apparatus 87 and in the width direction W by the second stretching apparatus 88. Thereby, the fibrous article 62 including the first fiber 51 and the second fiber 92 thinner than the first fiber 51 in the outer diameter is manufactured. Figure 2The winding roller R4 of the fiber sheet 60 after the pair of crimping rollers 27 (in other words, immediately after the first external force is applied). The fiber sheet 60 contains a plurality of first fibers 51 (as an example, short fibers 52) to which a plurality of resin granules 91 are attached.

[0105] Specifically, the first stretching device 87 has a drawing roller 65 that draws out the fiber sheet 60 from the winding roller R4, and a preheating roller set 70 that preheats the fiber sheet 60. The preheating roller set 70 includes a plurality of preheating rollers 71 to 74. Further, the manufacturing device 102 has a heating furnace 66 that heats the fiber sheet 60 that has been preheated, and two pairs of stretching rollers 67 and 68 that stretch the fiber sheet 60 that has passed through the heating furnace 66 in the conveyance direction P. As an example, the heating furnace 66 is a hot air furnace. The pair of stretching rollers 67 has a pair of stretching rollers 75 and 76. The pair of stretching rollers 68 has a pair of stretching rollers 77 and 78. Further, the manufacturing device 102 has a cooling roller set 69 that cools the fiber sheet 60 that has passed through the pair of stretching rollers 67 and 68. The cooling roller set 69 has a plurality of cooling rollers 79 to 81.

[0106] The second stretching device 88 has a heating furnace 84 that heats the fiber sheet 60 that is being conveyed in the conveyance direction P, and a stretching mechanism 85 that stretches the fiber sheet 60 in the width direction W by holding both ends in the width direction W of the fiber sheet 60 that is being heated and conveyed for a certain period. As an example, the heating furnace 84 is a hot air furnace. Further, the second stretching device 88 has a cooling and cutting device 83 that cools the fiber composite 61 obtained by the stretching mechanism 85 and cuts it to a prescribed width. The cooling and cutting device 83 has a pair of cooling rollers 95 and 96. Note that, regarding the configuration of the sequential biaxial stretching device, for example, refer to the description of Japanese Patent Application Publication No. 2006-096801.

[0107] When the manufacturing apparatus 102 is driven, a fiber sheet 60, after being subjected to a first external force and having that first external force mitigated, is heated by a furnace 66 in a first stretching device 87 and conveyed through the clamping points of stretching rollers 67 and 68. The fiber sheet 60 is stretched in the conveying direction P by the stretching rollers 67 and 68, thereby applying a second external force to the fiber sheet 60 in the conveying direction P. Furthermore, in the second stretching device 88, as the fiber sheet 60 passes through the furnace 84, a second external force is applied to the fiber sheet 60 in the width direction W by a stretching mechanism 85. Thus, a second external force is applied to the fiber sheet 60 in multiple directions including the width direction W. Furthermore, through the application of the second external force, multiple second fibers 92 are formed from multiple resin granules 91 of the fiber sheet 60. As a result, a fiber composite 61 comprising multiple first fibers 51 and multiple second fibers 92 is manufactured. In this way, in the third step of the method for manufacturing the fiber article 62 in this embodiment, the second external force is applied sequentially to the fiber sheet 60 along one of the width direction W and the conveying direction P and the other direction.

[0108] The fiber composite 61 is cooled by the cooling and cutting device 83 and cut to a specified width. Then, the fiber composite 61 is wound onto the winding roller R3 of the winding machine 31. The wound fiber composite 61 is further cut to a specified size, thereby producing a fiber article 62. In the second embodiment described above, the effects obtained from the first to third steps are achieved in the same way as in the first embodiment.

[0109] It should be noted that, as Figure 3 As shown, in the second embodiment, for example, the winding roller R5 can be formed by temporarily winding the fiber sheet 60 that has passed through the first extending device 87, and then the winding roller R5 is supplied to the second extending device 88. This allows for easy adjustment, for example, of the timing of applying the second external force sequentially to the fiber sheet 60 along the conveying direction P and the width direction W.

[0110] (Confirmation Test)

[0111] Next, the confirmatory tests and results of this disclosure will be described. This disclosure is not limited to the following embodiments.

[0112] [Experiment 1]

[0113] A fiber sheet 60 including a plurality of first fibers 51 (short fibers 52) as crimped CA fibers was prepared. Further, a plurality of resin granules 91 including PTFE was prepared. The first step to the third step were performed, whereby the fiber article 62 of Example 1 was manufactured. In this Example 1, in the first step, the plurality of resin granules 91 were attached to the plurality of first fibers 51 (short fibers 52) based on the impregnation method. Further, as the fiber sheet 60, a nonwoven fabric manufactured by the needle punching method was used. Further, in the second step, the heating temperature of the press roll pair 27 was set to 170°C. Further, the nip pressure of the press roll pair 27 as the first external force was set to 10 Mpa. Figure 4 is an enlarged photograph of the fiber sheet 60 of Example 1 before the second external force was applied. Figure 5 is an enlarged photograph of the fiber sheet 60 of Example 1 after the second external force was applied. In Figure 5 , in order to improve the visual confirmability, the silica powder was attached to the second fibers 92.

[0114] As shown in Figure 4 and Figure 5 , in Example 1, it was confirmed that the fiber gaps of the plurality of first fibers 51 included in the fiber sheet 60 before the second external force was applied were enlarged by the application of the second external force. Further, it was confirmed that the plurality of second fibers 92 were formed from the resin granules 91 in a manner of bridging between different plurality of first fibers 51 by the application of the second external force to the fiber sheet 60.

[0115] [Experiment 2]

[0116] A fiber sheet 60 including a plurality of first fibers 51 (short fibers 52) as crimped CA fibers was prepared. Further, a plurality of resin granules 91 including PTFE was prepared. The first step to the third step were performed, whereby the fiber article 62 of Example 1 was manufactured. In this Example 1, in the first step, the plurality of resin granules 91 were attached to the plurality of first fibers 51 (short fibers 52) based on the impregnation method. Further, as the fiber sheet 60, a nonwoven fabric manufactured by the needle punching method was used. Further, in the second step, the heating temperature of the press roll pair 27 was set to 170°C. Further, the nip pressure of the press roll pair 27 as the first external force was set to 10 Mpa.

[0117] The length dimension of the width direction (a direction corresponding to the width direction W of the fibrous sheet 60) of the manufactured Example 2 and Example 3 was elongated in a range of 30% or more and 90% or less of the elongation rate represented by the following equation 5. The pressure loss (Pa), the PF value, and the collection efficiency (%) of Example 2 and Example 3 with respect to the elongation rate (%) at that time were measured based on each method shown in the first embodiment. In addition, the thickness change rate (%) of Example 2 and Example 3 with respect to the elongation rate (%) at that time was measured. In addition, the weight per unit area (g / m2) of Example 2 and Example 3 with respect to the elongation rate (%) at that time was measured. 2 ).

[0118] [Equation 5]

[0119] Elongation rate (%) = (length after elongation L / natural length L0) x 100 - 100

[0120] Figure 6 is a graph showing the relationship between the elongation rate in the width direction of the fibrous article 62 of Example 2 and Example 3 and the pressure loss. In the results shown in Figure 6 , it was confirmed that both Example 2 and Example 3 were reduced in the pressure loss as the elongation rate increased. In addition, the content of the second fiber 92 of Example 3 was more than that of Example 2. Therefore, it was confirmed that the pressure loss of Example 3 was higher than that of Example 2 in the entire test range.

[0121] Figure 7 is a graph showing the relationship between the elongation rate in the width direction of the fibrous article 62 of Example 2 and Example 3 and the collection efficiency. In the results shown in Figure 7 , it was confirmed that both Example 2 and Example 3 were substantially maintained in the collection efficiency even as the elongation rate increased. In addition, the content of the second fiber 92 of Example 3 was more than that of Example 2. Therefore, it was confirmed that the collection efficiency of Example 3 was higher than that of Example 2 in the entire test range.

[0122] Figure 8 is a graph showing the relationship between the elongation rate in the width direction of the fibrous article 62 of Example 2 and Example 3 and the PF value. In the results shown in Figure 8 , it was confirmed that the PF value in Example 3 increased as the elongation rate increased from 30% to 50%, and then the PF value was substantially maintained even as the elongation rate increased. In addition, the same tendency was confirmed for the PF value of Example 2.

[0123] Figure 9 is a graph showing the relationship between the elongation rate in the width direction of the fibrous article 62 of Example 2 and Example 3 and the thickness change rate. In the results shown in Figure 9In the results shown, it was confirmed that both Example 2 and Example 3 were such that even if the elongation rate increased, the thickness did not greatly change. From this test result, it was considered that it was possible to manufacture the fibrous article 62 that would suppress the change in thickness caused by the change in elongation rate even if the content of the second fiber of the fibrous article 62 changed to some extent during the manufacturing process.

[0124] Figure 10 is a graph showing the relationship between the elongation rate in the width direction of the fibrous article 62 of Example 2 and Example 3 and the weight per unit area. In Figure 10 In the results shown, it was confirmed that both Example 2 and Example 3 were such that as the elongation rate increased, the weight per unit area slowly decreased.

[0125] [Experiment 3]

[0126] A fibrous sheet 60 including a plurality of first fibers 51 (staple fibers 52) of a synthetic fiber "SS-100" manufactured by Oshima Textile Co., Ltd. that was crimped was prepared. In addition, a plurality of resin granular materials 91 including PTFE were prepared. The first step to the third step were sequentially performed, whereby the fibrous article 62 of Example 4 including about 10% by mass of the second fiber 92 was manufactured. In the first step, the plurality of resin granular materials 91 were attached to the plurality of first fibers 51 (staple fibers 52) based on the gravure coating method. In the second step, the heating temperature of the press roller pair 27 was set to 110°C. In addition, the nip pressure of the first external force as the extension roller pair 67, 68 was set to 5 MPa. The size of the fibrous article 62 of Example 4 was set to 15 cm in length x 15 cm in width x 0.2 cm in thickness. In addition, the sequential biaxial extension device corresponding to the manufacturing device 102 of the second embodiment was used to apply the second external force to the fibrous sheet 60.

[0127] The length dimension in the width direction (the direction corresponding to the width direction W of the fibrous sheet 60) of the manufactured fibrous article 62 of Example 4 was elongated in a range of 40% or more and 100% or less from the natural length L0. The pressure loss (Pa), the PF value, and the collection efficiency (%) (using NaCl particles of 0.4 μm in particle diameter) of Example 4 with respect to the elongation rate (%) at that time were measured based on the method shown in the first embodiment. In addition, the weight per unit area (g / m2) of Example 4 with respect to the elongation rate (%) at that time was measured. 2 ).

[0128] Figure 11 is a graph showing the relationship between the elongation rate in the width direction of the fibrous article 62 of Example 4 and the pressure loss. In Figure 11 In the results shown, it was confirmed that Example 4, like Example 2 and Example 3, the pressure loss decreased as the elongation rate increased.

[0129] Figure 12is a graph showing the relationship between the elongation in the width direction of the fibrous article 62 of Example 4 and the collection efficiency. In Figure 12 In the results shown, it was confirmed that, as with Example 2 and Example 3, even if the elongation increases, the collection efficiency is substantially maintained.

[0130] Figure 13 is a graph showing the relationship between the elongation in the width direction of the fibrous article 62 of Example 4 and the PF value. In Figure 13 In the results shown, it was confirmed that the PF value of Example 4 substantially increases in a straight line shape as the elongation increases.

[0131] Figure 14 is a graph showing the relationship between the elongation in the width direction of the fibrous article 62 of Example 4 and the weight per unit area. In Figure 14 In the results shown, it was confirmed that the weight per unit area of Example 4 slowly decreases as the elongation increases. As a result, it was confirmed that even in the case where the fibrous article 62 is manufactured using the sequential double extension device, by changing the elongation by adjusting the strength of the second external force applied to the fibrous sheet 60, the weight per unit area of the fibrous article 62 can be adjusted.

[0132] Figure 15 is a graph showing the relationship between the elongation in the width direction of the fibrous article 62 of Example 4 and the thickness change rate. In Figure 15 In the results shown, it was confirmed that the thickness change rate increases as the elongation increases.

[0133] Further, with respect to Example 2 to Example 4, the J-ePM1 collection efficiency (%) was measured based on the method according to item 7.2 “Calculation of the particle material collection rate (J-eMPx)” of the general ventilation filter test (JIS B9908-1:2019). At the time of this measurement, as the particle material (PM1) for the test, a particle material (at least either one of a solid and a liquid particle floating in the atmosphere) obtained by cutting off 50% at an air kinetic particle diameter of 1 pm using a classification device was used.

[0134] Figure 16 is a graph showing the relationship between the J-ePM1 collection efficiency (%) of the fibrous article of Example 2 and Example 3 and the elongation. Figure 17 is a graph showing the relationship between the J-ePM1 collection efficiency (%) of the fibrous article of Example 4 and the elongation. In Figure 16 and Figure 17 In Figure 17 Data of Example 4 prepared in a plurality of

[0135] According to Figure 16The results of the measurement indicated that, in Example 2 and Example 3, the J-ePM1 collection efficiency (%) was a value of 50% or more in a range of 30% or more and 100% or less of elongation. Further, according to Figure 17 The results of the measurement indicated that, in Example 4, the J-ePM1 collection efficiency (%) was a value of 50% or more in a range of 50% or more and 100% of elongation.

[0136] As such, the J-ePM1 collection efficiency (%) of Example 2 to Example 4 was a value of 50% or more. Therefore, it was confirmed that Example 1 to Example 4 correspond to a filter group classified as “JIS-ePM1” in item 7.3 “Classification of categories” of JIS B 9908-1:2019. Thus, the fibrous article manufactured by the manufacturing method of the present disclosure can be said to be a filter having a high-quality filter function classified as “JIS-ePM1”.

[0137] (Disclosed Items)

[0138] The following items are the disclosure of the preferred embodiments.

[0139] [Item 1]

[0140] A manufacturing method of a fibrous article, having: a first step of adhering a plurality of resin particulates containing a high molecule capable of fiberization to a fibrous sheet containing a plurality of first fibers and being transported in a prescribed transport direction; a second step of applying a first external force to the plurality of first fibers and the plurality of resin particulates of the fibrous sheet to which the plurality of resin particulates is adhered and being transported, to make the fiber gap of the first fibers narrow; and a third step of applying a second external force to the fibrous sheet to which the first external force is relaxed and being transported in the transport direction, to make the fiber gap of the plurality of first fibers expand in at least a width direction of the fibrous sheet, thereby forming a plurality of second fibers finer than the first fibers from the plurality of resin particulates, and forming a fibrous composite containing the plurality of first fibers and the plurality of second fibers.

[0141] According to the above manufacturing method, in the third step, the fiber gap of the plurality of first fibers can be actively expanded in a direction in which the second external force is applied. Thus, the second external force can be applied to the resin particulates adhered to the plurality of first fibers, to form abundant second fibers from the plurality of resin particulates in a manner that the second fibers extend in the direction in which the second external force is applied. Therefore, the entanglement in at least the width direction of the fibrous sheet of the first fibers and the second fibers can be increased. Thus, the tensile strength in at least the width direction of the fibrous sheet can be improved by the first fibers and the second fibers. Therefore, in the case of manufacturing a fibrous article using the fibrous composite containing the plurality of first fibers and the plurality of second fibers, the strength improvement of the fibrous article can be sought.

[0142] Further, the fiber gap in the direction in which the second external force is applied is made wide in the fiber sheet being conveyed in the conveying direction. Thus, the weight per unit area of the fiber product can be reduced. Therefore, the weight reduction of the fiber product can be sought.

[0143] [Item 2]

[0144] The method of manufacturing a fiber product according to item 1, wherein in the third step, the second external force is applied to the fiber sheet in a state where the fiber sheet is heated.

[0145] According to the above manufacturing method, in the third step, by heating the plurality of resin particulates attached to the plurality of first fibers, the fine fibers folded and accommodated in the resin particulates can be easily pulled out to the outside by the second external force, and the second fibers can be easily formed to be rich.

[0146] [Item 3]

[0147] The method of manufacturing a fiber product according to item 1 or item 2, wherein in the third step, the second external force is further applied to the fiber sheet in the conveying direction of the fiber sheet.

[0148] According to the above manufacturing method, in the third step, by additionally applying the second external force to the plurality of resin particulates in the conveying direction, the fine fibers can be pulled out to the outside from the resin particulates, and the second fibers can be easily formed to be richer.

[0149] [Item 4]

[0150] The method of manufacturing a fiber product according to item 3, wherein in the third step, the second external force is applied to the fiber sheet in one direction and the other direction among the width direction and the conveying direction in turn.

[0151] According to the above manufacturing method, the timing of applying the second external force in one direction and the other direction among the width direction and the conveying direction can be staggered, and thus the second fibers can be formed to be rich. Therefore, the degree of freedom of setting of the manufacturing method can be improved.

[0152] [Item 5]

[0153] The method of manufacturing a fiber product according to item 1 or item 2, wherein in the third step, the second external force is applied to the fiber sheet in a plurality of directions including the width direction at the same time.

[0154] According to the manufacturing method described above, by simultaneously applying the second external force to the fibrous sheet in a plurality of directions including the width direction, abundant second fibers extending in a plurality of directions can be formed in a short time. Thus, the manufacturing efficiency of the fibrous article can be improved.

[0155] [Item 6]

[0156] The manufacturing method of the fibrous article according to any one of items 1 to 5, wherein, in the first step, a nonwoven fabric is used as the fibrous sheet.

[0157] According to the manufacturing method described above, in the case of manufacturing a fibrous article including first fibers and second fibers thinner in outer diameter than the first fibers and having a nonwoven fabric configuration, a fibrous article that seeks to be lightweight and have improved strength can be manufactured.

[0158] [Item 7]

[0159] The manufacturing method of the fibrous article according to any one of items 1 to 6, wherein, in the first step, the plurality of resin particulates having a sheet layer structure are used.

[0160] According to the manufacturing method described above, by the third step, using the plurality of resin particulates having a sheet layer structure, second fibers can be efficiently formed from the resin particulates.

[0161] [Item 8]

[0162] The manufacturing method of the fibrous article according to any one of items 1 to 7, wherein, in the first step, the plurality of first fibers that are crimped are used.

[0163] According to the manufacturing method described above, the first fibers can be configured to be more fluffy than first fibers in an uncrimped state. Thus, abundant inter-fiber gaps formed from the plurality of first fibers can be disposed in the fibrous article. Thus, the weight per unit area of the fibrous article can be reduced. Thus, a fibrous article that further seeks to be lightweight can be manufactured.

[0164] [Item 9]

[0165] The manufacturing method of the fibrous article according to any one of items 1 to 8, wherein, in the first step, the plurality of first fibers including at least one of a rayon, a polypropylene, a polyethylene terephthalate, a polyethylene, and a cellulose acetate are used.

[0166] According to the manufacturing method described above, the range of choices of materials for the first fibers can be expanded. Thus, the design freedom of the fibrous article can be improved.

[0167] [Item 10]

[0168] The method of manufacturing a fibrous article according to any one of items 1 to 9, wherein the high molecule capable of fiberization includes at least one of polytetrafluoroethylene, polypropylene, polyethylene, and polyamide.

[0169] According to the above manufacturing method, the range of materials of the second fibers can be expanded. Therefore, the design freedom of the fibrous article can be further improved by the manufacturing method as well.

[0170] [Item 11]

[0171] The method of manufacturing a fibrous article according to any one of items 1 to 10, wherein in the third step, the second external force is applied to the fibrous sheet in a manner that the fibrous composite forms a tensile strength in a direction perpendicular to the thickness direction that is in a range of 0.8 N / 10 mm or more and 100 N / 10 mm or less. 2 and 300 g / m 2 and 300 g / m

[0172] According to the above manufacturing method, the unit area weight of the fibrous article can be reduced, and a fibrous article including abundant inter-fiber gaps formed by the first fibers and the second fibers can be manufactured. Therefore, the lightweight of the fibrous article can be easily pursued. Further, according to the above manufacturing method, the lightweight of the manufactured fibrous article is pursued, and the strength is improved. Therefore, for example, a fibrous article with improved durability can be manufactured. Further, for example, the tensile strength of the plurality of first fibers in the fibrous article is improved. Thereby, for example, by increasing the second external force applied to the plurality of first fibers, more abundant inter-fiber gaps can be provided in the manufactured fibrous article. Further, by improving the tensile strength of the first fibers, when the strength of the second external force applied to the plurality of resin particulate matters is adjusted in the third step, the adjustment of the strength can be prevented from being restricted by the tensile strength of the first fibers. Thereby, the second fibers can be easily formed to be abundant.

[0173] [Item 12]

[0174] The method of manufacturing a fibrous article according to item 11, wherein in the third step, the second external force is applied to the fibrous sheet in a manner that the fibrous composite forms a tensile elongation in the direction of the strength minimum direction relative to a natural state that is in a range of 5% or more and 250% or less.

[0175] According to the above manufacturing method, further, the tensile elongation of the first fibers is improved, and therefore, when the strength of the second external force applied to the plurality of resin particulate matters is adjusted in the third step, the adjustment of the strength can be prevented from being restricted by the tensile elongation of the first fibers. Thereby, the second fibers can be more easily formed to be abundant.

[0176] [Item 13]

[0177] The manufacturing method of the fibrous article according to any one of Items 1 to 12, wherein, in the third step, the second external force is applied to the fibrous sheet in a manner to form the fibrous composite having a thickness in a natural state of a value in a range of less than 3.0 mm.

[0178] According to the above manufacturing method, the manufactured fibrous article can be constituted to be thin. Therefore, the fibrous article that seeks light weight and compactness and seeks strength improvement can be easily manufactured.

[0179] [Item 14]

[0180] The manufacturing method of the fibrous article according to any one of Items 1 to 13, wherein, in the third step, the second external force is applied to the fibrous sheet in a manner to form the fibrous composite having a pressure loss when air passes at a flow rate of 5.3 cm / sec in a thickness direction of a value in a range of 3 Pa or more and 35 Pa or less.

[0181] According to the above manufacturing method, the fibrous article that can seek light weight and strength improvement and can prevent clogging in use to efficiently circulate a fluid of a filtration object inside can be manufactured.

[0182] [Item 15]

[0183] The manufacturing method of the fibrous article according to any one of Items 1 to 14, wherein, in the third step, the second external force is applied to the fibrous sheet in a manner to form the fibrous composite having a trapping efficiency of a value in a range of 35% or more and 95% or less.

[0184] According to the above manufacturing method, by setting the trapping efficiency of the manufactured fibrous article to a value in the above range, the fibrous article that seeks light weight and strength improvement and has stable filter performance can be manufactured.

[0185] [Item 16]

[0186] The manufacturing method of the fibrous article according to any one of Items 1 to 15, wherein, in the third step, the second external force is applied to the fibrous sheet in a manner to form the fibrous composite that is classified into a filter group of JIS-ePM1 in a classification described in Item 7.3 of JIS B 9908-1:2019.

[0187] According to the above manufacturing method, the fibrous article that can be used for a high-quality filter classified into the filter group of “JIS-ePM1” can be manufactured.

[0188] Each of the configurations in each embodiment and combinations thereof are one example. Additional, omission, substitution, and other changes of the configurations can be appropriately made within a scope that does not depart from the gist of the present disclosure. The present disclosure is not limited by the embodiments, but is only limited by the claims. Furthermore, each of the aspects disclosed in the present specification can be combined with any of the other features disclosed in the present specification. The size of the fiber article 62 is not limited. Furthermore, the fiber article 62 can also be used in a state in which a plurality of fiber articles 62 or other configurations are combined.

[0189] Legend of Reference Numerals

[0190] 51: first fiber;

[0191] 60: fiber sheet;

[0192] 61: fiber composite;

[0193] 62: fiber article;

[0194] 91: resin particles;

[0195] 92: second fiber.

Claims

1. A method for manufacturing a fiber article, comprising: The first step is to apply multiple resin granules containing a fiber-forming polymer to a fiber sheet containing multiple first fibers and being conveyed in a specified conveying direction. The second step is to apply a first external force to the plurality of first fibers and the plurality of resin particles on the fiber sheet that is attached to and conveyed, so as to reduce the fiber gaps of the first fibers. as well as The third step involves applying a second external force to the fiber sheet that has been relaxed by the first external force and is being conveyed in the conveying direction, so as to widen the fiber gaps of the plurality of first fibers in at least the width direction of the fiber sheet, thereby forming a plurality of second fibers that are thinner than the first fibers from the plurality of resin granules, thus forming a fiber composite containing the plurality of first fibers and the plurality of second fibers.

2. The method for manufacturing fiber articles according to claim 1, wherein, In the third step, the second external force is applied to the fiber sheet while it is heated.

3. The method for manufacturing fiber articles according to claim 1, wherein, In the third step, the second external force is also applied to the fiber sheet along the conveying direction of the fiber sheet.

4. The method for manufacturing fiber articles according to claim 3, wherein, In the third step, the second external force is applied sequentially to the fiber sheet along one of the width direction and the conveying direction and the other direction.

5. The method for manufacturing fiber articles according to claim 1, wherein, In the third step, the second external force is applied simultaneously to the fiber sheet in multiple directions including the width direction.

6. The method for manufacturing a fiber article according to any one of claims 1 to 5, wherein, In the first step, nonwoven fabric is used as the fiber sheet.

7. The method for manufacturing a fiber article according to any one of claims 1 to 5, wherein, In the first step, the plurality of resin granules having a layered structure are used.

8. The method for manufacturing a fiber article according to any one of claims 1 to 5, wherein, In the first step, the multiple first fibers that have been curled are used.

9. The method for manufacturing a fiber article according to any one of claims 1 to 5, wherein, In the first step, the plurality of first fibers comprising at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, and cellulose acetate are used.

10. The method for manufacturing a fiber article according to any one of claims 1 to 5, wherein, The fibrous polymer comprises at least one of polytetrafluoroethylene, polypropylene, polyethylene, and polyamide.

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