JP7624302B2 - Method for manufacturing textile articles - Google Patents

Description

This disclosure relates to a method for manufacturing a textile article.

For example, textile articles are used as filtration members that filter impurities from fluids, and as absorbent members for sanitary products, etc. Patent Document 1 discloses a nonwoven fabric, which is a textile article containing different types of fibers. This document also discloses a manufacturing method for producing a nonwoven fabric by inserting one type of fiber into the fiber flow of the other type of fiber while spinning and transporting each type of fiber separately.

Japanese Unexamined Patent Publication No. 6-116854

When manufacturing textile articles containing different types of fibers, for example, by combining fibers with different outer diameters, the functions of each fiber can be expressed, improving the performance of the textile article. However, it can be difficult to efficiently manufacture textile articles with such high functionality. This problem becomes more pronounced, for example, when manufacturing textile articles containing fibers with extremely fine outer diameters.

Therefore, the present disclosure aims to enable efficient production of bulky, highly functional fiber articles when manufacturing fiber articles that combine types of fibers with different outer diameters.

In order to solve the above problem, a method for manufacturing a fiber article according to one embodiment of the present disclosure includes an attachment step of attaching a plurality of resin granules containing a fiberizable polymer to a plurality of first fibers, a first processing step of applying an external force to the plurality of first fibers to which the plurality of resin granules are attached so as to reduce the interfiber gaps while heating the plurality of first fibers and the plurality of resin granules, and a second processing step of forming a fiber composite containing the first fibers and the second fibers by relaxing the external force to form second fibers from the plurality of resin granules, the second fibers having an outer diameter smaller than that of the first fibers and set to a value in the range of 30 nm to 1.0 μm.

According to the above method, by carrying out each of the above steps, a bulky fiber article can be manufactured that contains ultra-fine second fibers with an outer diameter set to a value in the range of 30 nm to 1.0 μm and first fibers with an outer diameter larger than that of the second fibers. In addition, since the ultra-fine second fibers are combined with the first fibers and the second fibers are supported by the first fibers, a bulkier fiber article can be manufactured than when a fiber article is manufactured using only the second fibers. In addition, a highly functional fiber article that can perform the function of the second fiber for a long period of time can be manufactured. In addition, for example, by forming the second fibers from a plurality of resin granules dispersed and attached to the first fibers, the second fibers can be uniformly dispersed and arranged within the fiber article. Therefore, a fiber article with uniform quality can be manufactured.

In addition, by carrying out each of the above steps, for example, the above-mentioned fiber article can be efficiently and continuously manufactured using a single conveying facility. This simplifies the manufacturing process and reduces the manufacturing costs of the fiber article. As a result, bulky fiber articles with high functionality can be efficiently manufactured.

The method may further include a processing step of processing the plurality of first fibers into a sheet. This allows efficient production of a sheet-like fiber product containing the first fibers and the second fibers.

In the processing step, a nonwoven fabric may be formed from the plurality of first fibers. This allows efficient production of a fiber article using a nonwoven fabric containing the first fibers and the second fibers.

In the first processing step, the external force may be applied to the first fibers to which the resin granules are attached by pressing the first fibers with a pair of nip rolls. This allows the external force to be efficiently applied to the first fibers in the first processing step.

In the first processing step, the plurality of first fibers and the plurality of resin granules may be heated by the pair of heated nip rolls. This allows the nip rolls to also function as a heating device for heating the plurality of first fibers and the plurality of resin granules. This allows for simplification of the manufacturing apparatus.

Alternatively, in the first processing step, the external force may be applied to the first fibers to which the resin granules are attached by pressing the first fibers with a press device. Also, in the first processing step, the first fibers and the resin granules may be heated by the heated press device.

The heating temperature of the plurality of first fibers and the plurality of resin granules in the first processing step may be a temperature equal to or higher than the glass transition temperature of the first fibers. Also, the heating temperature of the plurality of first fibers and the plurality of resin granules in the first processing step may be a temperature in the range of 50°C or higher and 200°C or lower.

In the attachment step, a dispersion liquid in which the plurality of resin particles are dispersed may be used. When a dispersion liquid is used, the fluidity of the dispersion liquid makes it easier to attach the plurality of resin particles over a wide area of the surface of the first fiber.

The dispersion may be an aqueous dispersion in which the resin particles are dispersed in water. This allows the dispersion to be produced relatively inexpensively. In addition, the dispersion can be made easier to handle.

In the attachment step, the dispersion liquid detached from the first fibers in the first treatment step may be reused. This can facilitate further reduction in the manufacturing costs of the fiber article.

In the first processing step, the external force set to a value of 0.05 MPa or more may be applied to the first fibers to which the resin granules are attached. This allows sufficient external force to be applied to the resin granules, making it easier to form the second fibers.

In the attachment step, the plurality of resin granules having a lamellar structure may be used. This makes it easier to form second fibers from the plurality of resin granules in the second treatment step.

In the second processing step, the fiber composite may be formed in which the weight ratio W1/W2 between the total weight W1 of the first fibers and the total weight W2 of the second fibers and the remaining resin granules is set to a value in the range of 3.00 to 200.00. This allows the first fibers to stably support the second fibers, making it easier for the second fibers to exert their functions.

In the attachment step, the first fibers may be used whose outer diameter is set to a value in the range of 5 μm to 50 μm. This allows for greater freedom in designing the fiber article.

In the attachment step, the first fiber may contain at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, and cellulose acetate. In addition, in the attachment step, the resin granules may contain at least one of polytetrafluoroethylene, polypropylene, polyethylene, and polyamide.

The above method allows efficient production of fiber articles containing first and second fibers. Furthermore, by combining first and second fibers each containing a specific material, it is possible to make it easier for the first and second fibers to exert their respective functions.

According to each aspect of the present disclosure, when manufacturing a fiber article that combines types of fibers with different outer diameters, it is possible to efficiently manufacture a bulky fiber article with high functionality.

FIG. 1 is a schematic diagram of a tow band manufacturing apparatus according to a first embodiment. FIG. 2 is a schematic cross-sectional view of a tow band manufactured by the tow band manufacturing apparatus of FIG. 1 is a schematic diagram of a textile article manufacturing apparatus according to a first embodiment; FIG. 4 is a schematic cross-sectional view of a tow band thermally pressed by the heated nip roll pair of FIG. 4 is a cross-sectional view of a fiber composite (fiber article) manufactured by the fiber article manufacturing apparatus of FIG. 3. FIG. 5 is a schematic diagram of a textile article manufacturing apparatus according to a second embodiment. FIG. 11 is a schematic diagram of a textile article manufacturing apparatus according to a third embodiment.

Each embodiment will be described below with reference to the drawings.
First Embodiment
The method for manufacturing a fiber article of the first embodiment includes the following attachment step, first processing step, and second processing step. In the attachment step, a plurality of resin granules containing a polymer capable of being fiberized are attached to a plurality of first fibers. In the first processing step, an external force is applied to the plurality of first fibers to which the plurality of resin granules are attached so that the fiber gaps are reduced while the plurality of first fibers and the plurality of resin granules are heated. In the second processing step, the external force is relaxed to form a second fiber from the plurality of resin granules, the outer diameter of which is smaller than that of the first fibers and is set to a value in the range of 30 nm to 1.0 μm. In addition, in the second processing step, a fiber composite containing the first fibers and the second fibers is formed. In this embodiment, a heated nip roll pair is used as an example to perform the first and second processing steps. A tow band manufacturing apparatus and a fiber article manufacturing apparatus used in this manufacturing method will be described.

[Tow band manufacturing equipment]
FIG. 1 is an overall view of a tow band manufacturing apparatus 1 according to the first embodiment. The tow band manufacturing apparatus 1 shown in FIG. 1 spins a filament 61, which is a first fiber, by a dry spinning method. The tow band manufacturing apparatus 1 also manufactures a yarn 62, an end 63, and a tow band 64 from a plurality of filaments 61. The raw material of the filament 61 can be appropriately selected. As an example, the filament 61 contains at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, and cellulose acetate. The filament 61 of this embodiment contains cellulose acetate.

The tow band manufacturing apparatus 1 includes a mixing device 2, a filtering device 3, a spinning unit 4, a dispersion impregnation unit 5, an oil impregnation unit 6, a guide roll R1, a pair of conveying rolls 7, a crimping device 10, and a drying device 11. The spinning stock solution 60 used in the tow band manufacturing apparatus 1 is prepared by dissolving flakes such as cellulose diacetate in an organic solvent, for example. When the tow band manufacturing apparatus 1 is operated, the spinning stock solution 60 is mixed by the mixing device 2 and then filtered by the filtering device 3. The spinning stock solution 60 that has passed through the filtering device 3 is discharged from a plurality of spinning holes 15a of a spinneret 15 provided on the spinning tube 14 of the spinning unit 4.

The periphery of the spinning hole 15a is formed in a predetermined shape (for example, a circle). The diameter of the spinning hole 15a is appropriately set according to, for example, the monofilament fineness (FD) of the filament 61 after production. The spinning solution 60 discharged from each spinning hole 15a is heated by hot air supplied from a drying unit (not shown) into the spinning tube 14, and the organic solvent is evaporated and dried. As a result, multiple first fibers (filaments 61) are formed. The spinning method of the filaments 61 is not limited, and may be a method other than the dry spinning method (for example, a melt spinning method or a wet spinning method). The spinning method of the filaments 61 may be a method that can appropriately obtain the tow band 64.

As shown in FIG. 1, the dispersion liquid is applied to the filaments 61 that have passed through one spinning tube 14 by the dispersion liquid application unit 5. The dispersion liquid application unit 5 applies the dispersion liquid containing the resin granules 66 to the filaments 61. As an example, the dispersion liquid application unit 5 has a storage section that stores the dispersion liquid and an application roll that is supported so as to apply the dispersion liquid in the storage section to the peripheral surface and apply it to the filaments 61. The dispersion liquid in this embodiment is an aqueous dispersion liquid in which a plurality of resin granules 66 are dispersed in water. The dispersion liquid may contain a liquid other than water. This allows the dispersion liquid to be produced relatively inexpensively. In addition, the dispersion liquid can be made easier to handle.

The resin granules 66 contain a lamellar structure. The lamellar structure referred to here refers to a structure in which the polymer chains that make up the resin of the resin granules 66 are connected and folded. The lamellar structure contained within the resin granules 66 is specifically a fine fiber formed by millions of these polymer chains being connected in a ribbon shape. The fine fibers are folded and stored inside the resin granules 66.

The resin granules 66 are primary particles. A secondary particle is formed by bonding multiple resin granules 66 together. When an external force is applied to the secondary particles (in other words, two bonded resin granules 66) so that the resin granules 66 are pulled apart, fine fibers are pulled out from within the resin granules 66, and resin fibers 66a are formed from the resin granules 66. The dispersion liquid of this embodiment contains primary particles made of multiple resin granules 66 dispersed in a solvent. The dispersion liquid application unit 5 applies the dispersion liquid to the filament 61, so that the multiple resin granules 66 are dispersed and applied to the surface of the filament 61. As an example, multiple secondary particles of the resin granules 66 are applied to the surface of the filament 61.

As described below, an external force is applied to the filaments 61 to which the resin particles 66 are attached in this manner while the filaments 61 and the resin particles 66 are heated so that the interfiber gaps are reduced, thereby bonding the resin particles 66 attached to the surfaces of different filaments 61 together. In addition, the external force applied to the filaments 61 is relaxed, so that the bonded resin particles 66 are separated from each other. This forms resin fibers 66a (see Figures 2, 4, and 5).

The resin granules 66 of this embodiment may be, for example, produced by a polymerization reaction and contain a lamellar structure. As an example, the resin granules 66 contain at least one of PTFE (polytetrafluoroethylene), polypropylene, polyethylene, and polyamide. The resin granules 66 of this embodiment contain PTFE.

The resin granules 66 are set here to an average particle size in the range of 100 nm to 100 μm (approximately 300 nm, for example). As an example, the average particle size is more preferably in the range of 200 nm to 700 nm, and even more preferably in the range of 250 nm to 400 nm. The average particle size refers to the median diameter (cumulative 50% diameter (D50)) calculated from the measurement results by dynamic light scattering. As an example, the resin granules 66 are molded by paste extrusion molding.

The filaments 61 that have passed through the dispersion liquid application unit 5 are applied with fiber oil by the oil application unit 6. The filaments 61 that have passed through the oil application unit 6 are guided by a plurality of guide rolls R1, which are guide members, and are bundled together to form yarns 62. The yarns 62 are transported in a predetermined transport direction P. The yarns 62 are appropriately accumulated or stacked while being transported in the transport direction P. As a result, the yarns 62 are converged to form an end (tow) 63, which is a flattened assembly of the yarns 62. The end 63 is formed by converging the yarns 62 to a predetermined total fineness (TD). The end 63 is transported by a transport roll pair 7 having a pair of transport rolls 8 and 9, and is transported to the crimping device 10.

The crimping device 10 crimps the filament 61. As an example, the crimping device 10 has a pair of nip rolls N1, N2 and a stuffing box 18. The pair of nip rolls N1, N2 are arranged with their rotation axes parallel to each other. The pair of nip rolls N1, N2 press the end 63 with each other's peripheral surfaces.

The stuffing box 18 is disposed rearward of the pair of nip rolls N1, N2 in the conveying direction P. The stuffing box 18 has a pair of plate materials C1, C2 having plate surfaces extending in the conveying direction P, and a biasing member 12. The pair of plate materials C1, C2 are disposed so that their plate surfaces face each other with a gap G therebetween, and the gap G decreases from the front to the rear of the stuffing box 18 in the conveying direction P. Ends 63 (multiple filaments 61) that have passed through the pair of nip rolls N1, N2 are conveyed into the gap G.

The urging member 12 is, as an example, a plate material, and extends along the plate surface of the plate material C1 in a direction perpendicular to the conveying direction P. The front end of the urging member 12 in the conveying direction P is journaled to the plate material C1 so as to be freely rotatable about an axis Q extending in a direction perpendicular to the conveying direction P along the plate surface of the plate material C1. The urging member 12 is urged toward the plate surface of the plate material C2, and presses the end 63 conveyed between the pair of plate materials C1, C2.

The end 63 is pressed by the pair of nip rolls N1, N2 between the pair of nip rolls N1, N2. The end 63 is then pushed into the stuffing box 18. The end 63 is pressed against the plate surface of the plate material C2 by the biasing member 12 while being transported in a serpentine manner between the plate surfaces of the plate materials C1, C2. The end 63 is pressed into the stuffing box 18 by the pair of nip rolls N1, N2 with a force greater than the force that the end 63 receives from the plate materials C1, C2 and the biasing member 12, so that the end 63 is crimped. The end 63 passes through the crimping device 10 to form a tow band 64 processed into a sheet shape.

As an example, in the crimping device 10, the nip pressure of the pair of nip rolls N1, N2 is set to a value in an appropriate pressure range in order to appropriately crimp the filaments 61 and reduce the amount of dispersion liquid that falls off from the filaments 61. The tow band 64 that has passed through the crimping device 10 is dried by the drying device 11.

Figure 2 is a schematic cross-sectional view of a tow band 64 manufactured by the tow band manufacturing apparatus 1 of Figure 1. As shown in Figure 2, the tow band 64 has a plurality of crimped filaments 61 and a plurality of resin granules 66 dispersed inside the tow band 64 and supported by the filaments 61. There are fiber gaps between the plurality of filaments 61. The surface of the filament 61 is partially covered with a plurality of resin granules 66. As an example, the plurality of resin granules 66 are supported by the filaments 61 in the state of secondary particles bonded to each other. The tow band 64 is formed to be bulky by the crimped filaments 61.

The TD and FD of the tow band 64 can be set appropriately. As an example, the FD of the tow band 64 is set to a value in the range of 1.0 to 10.0. For example, from the viewpoint of maintaining a suitable strength of the filament 61 while ensuring a suitable fiber gap, it is desirable to set the FD of the tow band 64 to a value in the range of 2.0 to 6.0. As shown in FIG. 1, in this embodiment, the sheet-like tow band 64 that has passed through the drying device 11 is accumulated and then compressed and packed in a packing container 19 to become a bale. The packing container 19 in FIG. 1 shows a cross-sectional structure.

[PTFE used as material for resin granules 66]
Next, PTFE used as the material of the resin granules 66 will be described. This PTFE is configured as a polymer that can be made into a fiber. Such PTFE is, for example, high molecular weight PTFE obtained by emulsion polymerization or suspension polymerization of TFE (tetrafluoroethylene). The high molecular weight PTFE may be at least one of modified PTFE and homo-PTFE.

Modified PTFE includes TFE and monomers other than TFE (modified monomers). Modified PTFE is generally one that is uniformly modified with a modified monomer, or one that is modified at the beginning or end of the polymerization reaction, but is not particularly limited thereto. Modified PTFE contains TFE units based on TFE and modified monomer units based on a modified monomer.

Modified monomer units are a part of the molecular structure of modified PTFE, and are derived from modified monomers. Total monomer units are derived from all monomers in the molecular structure of modified PTFE. There are no particular limitations on the modified monomer, so long as it can be copolymerized with TFE.

The "high molecular weight" of high molecular weight PTFE referred to here is a molecular weight that is easily fiberized during the production of the tow band 64, that produces long fibrils, that has a standard specific gravity (SSG) in the range of 2.130 to 2.230, and that does not melt and flow due to its high melt viscosity. For information on fiberizable PTFE, see, for example, International Publication No. WO 2013/157647.

When resin fibers 66a are formed from resin granules 66 containing PTFE, the extensibility of the resin fibers 66a is improved by heating the resin granules 66. If the resin fibers 66a have good extensibility, the resin fibers 66a are less likely to be cut when the resin fibers 66a are formed from the resin granules 66. This improves the expressibility of the resin fibers 66a.

[Textile article manufacturing equipment]
Fig. 3 is an overall view of the textile article manufacturing apparatus 20 according to the first embodiment. The packaging container 19 in Fig. 3 shows a cross-sectional structure. As shown in Fig. 3, the textile article manufacturing apparatus 20 includes, as an example, a converging ring 21, a first opening unit 22, a turn baffle 23, a second opening unit 24, a pretension roll pair 25, a first opening roll pair 26, a second opening roll pair 27, a third opening unit 28, a heating nip roll pair 29, a conveying roll pair 30, and a winding roll 31.

The convergence ring 21 and the turn baffle 23 guide the bale-shaped tow band 64 that is raised from the packing container 19 toward the first opening unit 22. The first opening unit 22, the second opening unit 24, and the third opening unit 28 open the tow band 64 in its width direction by gas (compressed air as an example). The pretension roll pair 25, the first opening roll pair 26, and the second opening roll pair 27 open the tow band 64 in the width direction and the conveying direction P while applying tension to the tow band 64 in the conveying direction P.

The pretension roll pair 25 has a pair of rolls 32, 33 arranged with their circumferential surfaces facing each other. The first opening roll pair 26 has a pair of rolls 34, 35 arranged with their circumferential surfaces facing each other. The second opening roll pair 27 has a pair of rolls 36, 37 arranged with their circumferential surfaces facing each other. As an example, the peripheral surfaces of rolls 34 to 37 are formed with grooves extending in the circumferential direction, and are configured to make it easier to open the tow band 64.

The heating nip roll pair 29 has a pair of rolls N3 and N4 arranged with their circumferential surfaces facing each other. The heating nip roll pair 29 applies an external force to the filaments 61 to which the resin granules 66 are attached in the tow band 64, heating the filaments 61 and the resin granules 66 while reducing the interfiber gaps.

The transport roll pair 30 has a pair of rolls 38, 39 arranged with their circumferential surfaces facing each other. The transport roll pair 30 transports the tow band 64 that has passed through the heating nip roll pair 29 to the winding roll 31 side. The winding roll 31 winds up the tow band 64 that has passed through the transport roll pair 30.

When the textile product manufacturing device 20 is in operation, the tow band 64 is pulled up from the packing container 19, passed through the convergence ring 21, and then spread in the width direction by the first spreading unit 22. The tow band 64 is then guided by the turn baffle 23 to the second spreading unit 24.

Next, the tow band 64 is further opened in the width direction by the second opening unit 24. The tow band 64 is then inserted between the rolls 32 and 33, between the rolls 34 and 35, and between the rolls 36 and 37 in that order. The tow band 64 comes into contact with the rolls 32 to 37. The rotation speed of the pair of rolls 36 and 37 is faster than the rotation speed of the pair of rolls 34 and 35. As a result, the tow band 64 is bulkily opened in the conveying direction P and the width direction while tension is applied in the conveying direction P by the first opening roll pair 26 and the second opening roll pair 27.

Here, FIG. 4 is a schematic cross-sectional view of a tow band 64 that has been thermally bonded by the heated nip roll pair 29 of FIG. 3. FIG. 5 is a cross-sectional view of a fiber composite 67 (fiber article 65) manufactured by the fiber article manufacturing apparatus 20 of FIG. 3. The opened tow band 64 that has passed through the second opening roll pair 27 is introduced into the nip point N5 of the heated nip roll pair 29.

As shown in Figures 4 and 5, when the tow band 64 passes through the pair of heated nip rolls 29, a nip pressure is applied as an external force to the filaments 61 to which the resin granules 66 are attached, so that the filaments 61 and the resin granules 66 are heated and the interfiber gaps between the filaments 61 are reduced. As a result, the interfiber gaps between the filaments 61 are reduced, and the resin granules 66 attached to the filaments 61 are bonded to each other to form higher-order particles of the resin granules 66. The external force is then alleviated as the filaments 61 pass through the nip point N5.

When this external force is relaxed, tension is applied to the resin granules 66 so as to separate the resin granules 66 that are bonded to each other between different filaments 61. This causes the fine fibers folded in the resin granules 66 to be stretched, and resin fibers 66a are formed to bridge the multiple different filaments 61. As a result, a fiber composite 67 containing the filaments 61 and the resin fibers 66a is formed. In this way, in this embodiment, by using the heated nip roll pair 29, the resin fibers 66a and the fiber composite 67 can be formed relatively easily.

In this embodiment, the resin fibers 66a are formed using the heating nip roll pair 29, but the resin fibers 66a may be formed by heating the filaments 61 and the resin granules 66 using a heating device separate from the heating nip roll pair 29. The external force may be applied to the filaments 61 using something other than nip rolls. Therefore, for example, the resin fibers 66a can be formed by applying nip pressure as the external force to the filaments 61 to which the resin granules 66 are attached, while heating the filaments 61 and the resin granules 66, from at least one of the first opening roll pair 26 and the second opening roll pair 27.

The outer diameter of the resin fiber 66a can be adjusted, for example, by the magnitude of the tension applied to the resin granules 66. For example, by increasing the tension, the outer diameter of the resin fiber 66a can be set small and the length dimension of the resin fiber 66a can be set long. By decreasing the tension, the outer diameter of the resin fiber 66a can be set large and the length dimension of the resin fiber 66a can be set short. By making such adjustments, in this embodiment, the outer diameter of the resin fiber 66a can be set to a value in the range of 30 nm or more and 1.0 μm or less.

The fiber composite 67 that has passed through the pair of heated nip rolls 29 is transported by the pair of transport rolls 30 and wound up on the winding roll 31. The fiber composite 67 is cut, for example, to a predetermined size to produce a fiber article 65. The resin fibers 66a are supported by the filaments 61 while being entangled with the filaments 61 inside the fiber article 65. Therefore, even if the resin fibers 66a are significantly thinner than the filaments 61, the resin fibers 66a can be supported by the filaments 61 while preventing the resin fibers 66a from being cut. Therefore, the function of the resin fibers 66a can be maintained for a long period of time. The resin fibers 66a are arranged so as to be diffused throughout the inside of the tow band 64. The resin granules 66 in the fiber article 65 may shrink or disappear in some cases as the resin fibers 66a are formed.

The fiber article 65 is formed bulkily by a plurality of opened filaments 61 with abundant fiber gaps inside. Therefore, the fiber article 65 has, for example, a soft and pleasant feel. The fiber article 65 is, for example, in a sheet shape. The fiber article 65 may be formed by stacking and pressing a plurality of sheet-shaped fiber composites 67. In this case, for example, the thickness dimension of the fiber article 65 can be easily designed by changing the number of fiber composites 67. The fiber article 65 may also be formed by arranging a plurality of sheet-shaped fiber composites 67 in the width direction. In this case, for example, the width dimension of the fiber article 65 can be easily designed by adjusting the number of fiber composites 67.

The value of the external force applied to the filaments 61 to form the resin fibers 66a can be set as appropriate, but can be, for example, a value of 0.05 MPa or more. When the fiber article 65 is used as a filtering member, it is desirable to apply the external force to the filaments 61 to a value of, for example, 0.10 MPa or more in order to obtain good filtering performance. The upper limit of the external force may be, for example, a value of several tens of MPa or more.

The heating temperature at which the filaments 61 and the resin granules 66 are heated to form the resin fibers 66a can be set appropriately, but can be, for example, a temperature in the range of 50°C to 200°C. This heating temperature can be set based on the characteristics of the resin granules 66 or the resin fibers 66a.

The heating temperature can be set to, for example, a temperature equal to or higher than the glass transition temperature (Tg) of the filament 61. When the filaments 61 and the resin granules 66 are heated at such a heating temperature to apply the external force to the filaments 61, the filaments 61 can retain the compressed state due to the external force to some extent even after the external force is relieved. This makes it easier to set the bulk of the fiber article 65 to an arbitrary thickness. As an example, when the filaments 61 are cellulose acetate fibers, the glass transition temperature of the filaments 61 is, for example, 70°C at room temperature of 20°C and humidity of 65%. Therefore, by setting the heating temperature to 70°C or higher, for example, a sheet-like fiber article 65 with a small bulk can be efficiently manufactured. The heating temperature may also be, for example, lower than the melting point of each material of the filaments 61 and the resin granules 66, or lower than the decomposition temperature of each material.

As described above, the fiber product 65 is manufactured by a manufacturing method using the tow band manufacturing device 1 and the fiber product manufacturing device 20. This manufacturing method includes an attachment step, a first processing step, and a second processing step.

The attachment step is a step of attaching a plurality of resin particles 66 containing a polymer capable of being fiberized to a plurality of filaments 61. In the attachment step of this embodiment, a dispersion liquid containing a plurality of resin particles 66 that contain a lamellar structure and are bonded to each other is attached to the plurality of filaments 61. The first processing step is a step of applying an external force to the plurality of filaments 61 to which the plurality of resin particles 66 have been attached, while heating the plurality of filaments 61 and the plurality of resin particles 66, so as to reduce the interfiber gaps.

The manufacturing method of this embodiment also includes a processing step of processing the multiple filaments 61 into a sheet. As another example, in the first processing step, the multiple filaments 61 are pressed by a pair of nip rolls, thereby applying the external force to the filaments 61 to which the multiple resin particles 66 are attached. As a further example, in the first processing step, the multiple filaments 61 and the multiple resin particles 66 are heated by a pair of heating nip rolls 29.

In the first processing step of this embodiment, as an example, the external force set to a value of 0.05 MPa or more is applied to the multiple filaments 61 to which the multiple resin particles 66 are attached. As an example, this nip pressure is applied by the heated nip roll pair 29. In the present embodiment, as an example, the dispersion liquid detached from the filaments 61 in the first processing step is recovered, and the recovered dispersion liquid is used in the attachment step.

In addition, in the fiber composite 67, the weight ratio W1/W2 between the total weight W1 of the filaments 61 and the total weight W2 of the resin fibers 66a and the remaining resin granules 66 can be set appropriately. In the second processing step of this embodiment, as an example, a fiber composite 67 is formed in which the weight ratio W1/W2 is set to a value in the range of 3.00 to 200.00. This allows the resin fibers 66a to be stably supported by the filaments 61 in the fiber article 65, making it easier for the resin fibers 66a to perform their functions.

In addition, in the attachment step, a filament 61 is used whose outer diameter is set to a value in the range of 5 μm to 50 μm. This increases the difference in outer diameter between the first fiber and the second fiber, improving the design freedom of the fiber article 65.

By setting the weight ratio W1/W2 to a value within the above range, the volume ratio V1/V2 between the total volume V1 of the filaments 61 (first fibers) and the total volume V2 of the resin fibers 66a (second fibers) and the remaining resin granules 66 has a maximum value of 124.0 or less. This makes it possible to ensure appropriate fiber gaps inside the fiber article 65, stably hold the resin fibers 66a by the filaments 61, and facilitate the resin fibers 66a to exhibit their functions.

The length dimension of the filament 61 and the length dimension of the resin fiber 66a can be set as appropriate. In the second processing step of this embodiment, a fiber composite 67 is formed in which the length dimension of the filament 61 is longer than the length dimension of the resin fiber 66a. This allows, for example, the filament 61 to be used as the skeleton of the fiber article 65, and the filament 61 to carry the resin fiber 66a, thereby allowing the function of the resin fiber 66a to be stably exerted.

As described above, according to the manufacturing method of this embodiment, by performing each of the above steps, a bulky fiber article 65 containing ultrafine resin fibers 66a whose outer diameter is set to a value in the range of 30 nm to 1.0 μm and filaments 61 whose outer diameter is thicker than that of the resin fibers 66a can be manufactured. In addition, since the ultrafine resin fibers 66a are combined with the filaments 61 and the resin fibers 66a are supported by the filaments 61, a bulkier fiber article 65 can be manufactured than when a fiber article is manufactured using only the resin fibers 66a. In addition, a highly functional fiber article 65 that can demonstrate the function of the resin fibers 66a for a long period of time can be manufactured. In addition, for example, by forming the resin fibers 66a using a plurality of resin granules 66 dispersed and attached to the filaments 61, the resin fibers 66a can be uniformly dispersed and arranged within the fiber article 65. Thus, a fiber article 65 with uniform quality can be manufactured.

In addition, by performing each of the above steps, for example, the fiber article 65 can be efficiently and continuously manufactured using a single conveying facility. Therefore, the manufacturing process can be simplified and the manufacturing cost of the fiber article 65 can be reduced. As a result, a highly functional and bulky fiber article 65 can be efficiently manufactured. In addition, according to this embodiment, a fiber article 65 having both good bulkiness and porosity, which was previously difficult to achieve, can be relatively easily and efficiently manufactured. Furthermore, a bulky fiber article 65 containing ultrafine fibers with an outer diameter of 1.0 μm or less, which was previously difficult to mass-produce stably, can be successfully manufactured. In addition, the manufacturing method of this embodiment has a processing step of processing multiple filaments 61 into a sheet shape. This allows efficient manufacturing of a sheet-shaped fiber article 65 containing filaments 61 and resin fibers 66a.

In addition, in the first processing step of this embodiment, as an example, the external force is applied to the filaments 61 to which the multiple resin particles 66 are attached by pressing the multiple filaments 61 with a pair of heated nip rolls 29. This allows the external force to be efficiently applied to the filaments 61 in the first processing step.

In the first processing step, the filaments 61 and the resin granules 66 are heated by the heating nip roll pair 29. This allows the heating nip roll pair 29 to also function as a heating device for heating the filaments 61 and the resin granules 66. This simplifies the fiber article manufacturing device. In this embodiment, the heating temperature of the filaments 61 and the resin granules 66 in the first processing step is set to a temperature in the range of 50°C to 200°C.

In the attachment step, as an example, a dispersion liquid in which multiple resin particles 66 are dispersed is used. When a dispersion liquid is used, the fluidity of the dispersion liquid makes it easier to attach multiple resin particles 66 to a wide area of the surface of the filament 61. In addition, in the attachment step of this embodiment, the dispersion liquid detached from the filament 61 in the first treatment step is reused. This makes it easier to further reduce the manufacturing cost of the fiber article 65.

As another example, in the first processing step, the external force set to a value of 0.05 MPa or more is applied to the multiple filaments 61 to which the multiple resin granules 66 are attached. This allows sufficient external force to be applied to the multiple resin granules 66, making it easier to form the resin fibers 66a.

In addition, in the attachment step of this embodiment, multiple resin particles 66 having a lamellar structure are used. This makes it easier to form resin fibers 66a from the multiple resin particles 66 in the second processing step.

In the second processing step, a fiber composite 67 is formed in which the weight ratio W1/W2 is set to a value in the range of 3.00 to 200.00. This allows the filament 61 to stably support the resin fiber 66a, making it easier for the resin fiber 66a to perform its function. In the attachment step, as an example, a filament 61 is used whose outer diameter is set to a value in the range of 5 μm to 50 μm. This increases the difference in outer diameter between the filament 61 and the resin fiber 66a, improving the design freedom of the fiber article 65.

In addition, in the attachment step of this embodiment, filaments 61 containing at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, and cellulose acetate are used. In addition, in the attachment step of this embodiment, resin granules 66 containing at least one of polytetrafluoroethylene, polypropylene, polyethylene, and polyamide are used.

The above method allows efficient production of a fiber article 65 containing filaments 61 and resin fibers 66a. In addition, by combining filaments 61 and resin fibers 66a each containing a specific material, it is possible to make it easier for the filaments 61 and resin fibers 66a to exert their respective functions.

In this embodiment, the process of packaging the tow band 64 manufactured by the tow band manufacturing apparatus 1 in the packaging container 19 is shown. However, the tow band 64 may be introduced into the fiber article manufacturing apparatus 20 without packaging to manufacture the fiber article 65. The configuration of the fiber article manufacturing apparatus 20 is not limited to the above. In addition, as the dispersion liquid used in the attachment step, for example, a slurry containing a relatively large amount of resin granules 66 may be used.

The resin granules 66 may also be attached to the filament 61 after the yarn 62 or end 63 is formed. The tow band manufacturing apparatus 1 may also be equipped with a powder addition unit that applies powdered resin granules 66 to the filament 61 instead of the dispersion liquid application unit 5. When multiple filaments 61 are processed into a sheet, the application step may be performed either before or after the multiple filaments 61 are processed into a sheet.

Next, modified examples of this embodiment will be described. In the first processing step of the first modified example, a press device is used to press a plurality of filaments 61 (e.g., a plurality of filaments 61 after being opened), thereby applying the external force to the filaments 61 to which a plurality of resin particles 66 are attached. In addition, in the first processing step of the second modified example, the heated press device is used to further heat the plurality of filaments 61 and the plurality of resin particles 66. Using these manufacturing methods, the fiber article 65 can be similarly manufactured. Below, the other embodiments will be described, focusing on the differences from the first embodiment.

Second Embodiment
FIG. 6 is a schematic diagram of a fiber article manufacturing apparatus 120 according to the second embodiment. In this embodiment, as an example, a manufactured bale-shaped tow band 164 (without resin granules 66) is used. As shown in FIG. 6, the fiber article manufacturing apparatus 120 includes a plurality of guide members (guide rolls R2 to R7 as an example) arranged in a distributed manner to guide the tow band 164 unwound from the packing container 19 in the conveying direction P, an attachment unit 105 that applies a dispersion to the conveyed tow band 164, and a spreading unit 124 into which the tow band 164 to which the dispersion is applied is introduced. The fiber article manufacturing apparatus 120 also includes a first spreading roll pair 26, a second spreading roll pair 27, a heating device 16, and a nip roll pair 129. The nip roll pair 129 is disposed in the heating device 16 and heated.

Inside the attachment unit 105, the tow band 164 is guided by the guide rolls R4 and R5 and immersed in the dispersion liquid based on the dip coating method, so that the dispersion liquid is attached to the tow band 164. The tow band 164 to which the dispersion liquid is attached in the attachment unit 105 is opened by the opening unit 124, the first opening roll pair 26, and the second opening roll pair 27. The tow band 164 is then introduced into the heating device 16 and preheated while passing through the nip roll pair 129 heated by the heating device 16. This causes the first and second processing steps to be performed, and the resin fiber 66a and the fiber composite 167 are formed. The fiber composite 167 is cut, for example, to a predetermined size, to manufacture the fiber article 165. According to this embodiment, for example, the tow band 164 manufactured by the conventional method can be used to efficiently manufacture the fiber article 165 containing the resin fiber 66a.

Third Embodiment
7 is a schematic diagram of a fiber article manufacturing apparatus 220 according to the third embodiment. In this embodiment, a bale-shaped tow band 164 (without resin granules 66) is used as in the second embodiment. As shown in FIG. 7, the manufacturing apparatus 220 includes a staple fiber processing device 40, a nonwoven fabric processing device 41, and a heat press device 17.

The short fiber processing device 40 cuts the filaments 61 of the tow band 164, which has been applied with a dispersion liquid by the application unit 105 and is guided by the guide rolls R2 to R8, into short fibers. The nonwoven fabric processing device 41 processes the multiple short filaments 61 discharged from the short fiber processing device 40 into a sheet to form a nonwoven fabric. The nonwoven fabric processing device 41 forms a nonwoven fabric based on, for example, a known nonwoven fabric manufacturing method (such as a fleece formation method or a fleece bonding method).

The heat press device 17 heats and presses the nonwoven fabric discharged from the nonwoven fabric processing device 41. The nonwoven fabric passes through the heat press device 17, whereby the first and second processing steps are carried out. This results in the production of a textile product 265 using the nonwoven fabric.

In this way, in the processing step of the manufacturing method of the fiber article 265 of this embodiment, a nonwoven fabric is formed from the multiple filaments 61. In the first processing step, the multiple filaments 61 and the multiple resin particles 66 are heated and pressed. That is, in the first processing step, the multiple filaments 61 are pressed by the heat press device 17, thereby applying the external force to the filaments 61 to which the multiple resin particles 66 are attached. In the first processing step, the multiple filaments 61 and the multiple resin particles 66 are heated by the heated heat press device 17. This allows the fiber article 265 using the nonwoven fabric containing the filaments 61 and the resin fibers 66a to be efficiently manufactured.

The heating device that heats the multiple filaments 61 and the multiple resin granules 66 and the pressing device that applies the external force to the filaments 61 to which the multiple resin granules 66 are attached by pressing the multiple filaments 61 may be configured separately.

(Confirmation test)
A confirmation test was carried out according to the following procedure. Based on the first embodiment, a fiber article 65 was prepared as Examples 1 to 3, in which the filament 61, which is the first fiber, was made of cellulose acetate and the resin fiber 66a, which is the second fiber, was made of PTFE. In Examples 1 to 3, the heating temperature of the filaments 61 and the resin granules 66 in the first treatment step was changed within a range of 50°C to 100°C.

Furthermore, fiber articles manufactured by forming the filament 61, which is the first fiber, from cellulose acetate and the resin fiber 66a, which is the second fiber, from PTFE were prepared as Comparative Examples 1 and 2. Comparative Example 1 was set up similarly to Examples 1 to 3, except that heating was not performed in the first treatment step. Comparative Example 2 was set up similarly to Examples 1 to 3, except that the first treatment step was not performed.

A fiber article was prepared as Comparative Example 3, in which the filament 61, which is the first fiber, was made of cellulose acetate, no resin granules 66 were attached to the filament 61, and the filament 61 was heated to 100° C. A fiber article was prepared as Comparative Example 4, in which the filament 61, which is the first fiber, was made of cellulose acetate, no resin granules 66 were attached to the filament 61, and the filament 61 was not heated. In Examples 1 to 3 and Comparative Examples 1 to 4, cellulose acetate with a monofilament fineness (FD) of 2 was used, the basis weight of the cellulose acetate was set to 150 g/m ² , and the amount of PTFE particles attached was set to about 10 wt %. The nip pressure of the heated nip roll pair 29 was set to 0.4 MPa.

In order to confirm the performance when the obtained fiber articles of Examples 1 to 3 and Comparative Examples 1 to 4 were used as filter members, the collection efficiency (%) was measured. This collection efficiency was measured as the particle collection efficiency when air containing NaCl particles with a particle diameter of 0.4 μm was passed through at a flow rate of 5.3 cm/sec. The test results are shown in Table 1.

As shown in Table 1, it was confirmed that Examples 1 to 3 all had good performance. It was confirmed that Comparative Examples 1 and 2 formed second fibers, but had inferior performance as fiber articles to Examples 1 to 3. It was confirmed that Comparative Examples 3 and 4 did not form second fibers and had no collection efficiency. From the above, the superiority of Examples 1 to 3 was confirmed.

Each configuration and their combinations in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of configurations are possible as appropriate within the scope of the present disclosure. This disclosure is not limited to the embodiments, but only by the claims. Furthermore, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. The fiber article of this disclosure is naturally not limited to a filtration member, and may be an article for other uses.

P: conveying direction 17: heat press device (press device)
29 Heated nip roll pair (pair of nip rolls)
61 Filament (first fiber)
64, 164 Tow band 65, 165, 265 Fiber article 66 Resin granules 66a Resin fiber (second fiber)
67, 167 Fiber composite

Claims (18)

an impregnation step of impregnating a plurality of resin granules containing a fiberizable polymer onto a plurality of continuous first fibers while conveying the plurality of first fibers;
a first treatment step of applying an external force to the first fibers to which the resin granules are attached so that inter-fiber gaps are reduced while heating the first fibers and the resin granules;
A method for manufacturing a fiber article, comprising: a second processing step of forming second fibers from the plurality of resin granules, the second fibers having an outer diameter smaller than that of the first fibers and set to a value in the range of 30 nm or more and 1.0 μm or less, by relaxing the external force, and forming a fiber composite containing the first fibers and the second fibers. The method for manufacturing a fiber article according to claim 1, further comprising a processing step of processing the plurality of first fibers into a sheet shape. The method for manufacturing a fiber article according to claim 2, wherein in the processing step, a nonwoven fabric is formed from the plurality of first fibers. The method for manufacturing a fiber article according to any one of claims 1 to 3, wherein in the first treatment step, the external force is applied to the first fibers to which the resin granules are attached by pressing the first fibers with a pair of nip rolls. The method for manufacturing a fiber article according to claim 4, wherein in the first treatment step, the plurality of first fibers and the plurality of resin granules are heated by the pair of heated nip rolls. The method for manufacturing a fiber article according to any one of claims 1 to 3, wherein in the first processing step, the external force is applied to the first fibers to which the resin granules are attached by pressing the first fibers with a press device. The method for manufacturing a fiber article according to claim 6, wherein in the first processing step, the plurality of first fibers and the plurality of resin granules are heated by the heated press device. The method for manufacturing a fiber article according to any one of claims 1 to 7, wherein the heating temperature of the first fibers and the resin granules in the first treatment step is set to a temperature equal to or higher than the glass transition temperature of the first fibers. The method for manufacturing a fiber article according to any one of claims 1 to 8, wherein the heating temperature of the first fibers and the resin granules in the first treatment step is in the range of 50°C to 200°C. The method for manufacturing a fiber article according to any one of claims 1 to 9, wherein the attachment step uses a dispersion liquid in which the plurality of resin granules are dispersed. The method for producing a fiber article according to claim 10 , wherein the dispersion liquid is an aqueous dispersion liquid in which the plurality of resin granules are dispersed in water. The method for manufacturing a fiber article according to claim 10 or 11, wherein in the attachment step, the dispersion liquid detached from the first fiber in the first treatment step is reused. The method for manufacturing a fiber article according to any one of claims 1 to 12, wherein in the first treatment step, the external force set to a value of 0.05 MPa or more is applied to the first fibers to which the resin granules are attached. The method for manufacturing a fiber article according to any one of claims 1 to 13, wherein the attachment step uses the plurality of resin particles having a lamellar structure. The method for manufacturing a fiber article according to any one of claims 1 to 14, wherein in the second processing step, the fiber composite is formed with a weight ratio W1/W2 of the total weight W1 of the first fibers to the total weight W2 of the second fibers and the remaining resin granules set to a value in the range of 3.00 to 200.00. The method for manufacturing a fiber article according to any one of claims 1 to 15, wherein the first fiber has an outer diameter set to a value in the range of 5 μm to 50 μm in the attachment step. The method for manufacturing a fiber article according to any one of claims 1 to 16, wherein the first fiber contains at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, and cellulose acetate in the attachment step. The method for manufacturing a fiber article according to any one of claims 1 to 17, wherein the resin granules contain at least one of polytetrafluoroethylene, polypropylene, polyethylene, and polyamide in the attachment step.

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