Patent Description:
A fiber article is used, for example, as a filtration member that filters impurities from fluid, or as an absorbent member such as a sanitary product. Patent Document <NUM> discloses a nonwoven fabric that is a fiber article including different types of fibers. The present document discloses a production method for producing a nonwoven fabric by inserting a fiber stream of one type of fiber into the other fiber stream of another type of fiber while separately spinning and transferring the respective types of fibers.

In a fiber article including different types of fibers, for example, fibers having different outer diameters are combined and the fiber article is configured to be bulky. Consequently, the function of each of type of fiber can be achieved and the performance of the fiber article can be improved. However, it may be difficult to efficiently produce such a fiber article that has high functionality. This problem is particularly prominent in a case where fibers having an extremely small outer diameters are used.

Therefore, an object of the present disclosure is to allow for, in the case of producing a fiber article by combining different types of fibers having different outer diameters, efficiently producing a bulky fiber article having high functionality.

In order to solve the problem described above, a production method for a fiber article includes: a contact step of, while transferring a plurality of first fibers, bringing a plurality of resin particles formed of polytetrafluoroethylene (PTFE) that can be fiberized into contact with the plurality of first fibers; a first processing step of applying an external force to the plurality of first fibers brought into contact with the plurality of resin particles and narrowing gaps between fibers; and a second processing step of, by relieving the external force applied to the plurality of first fibers brought into contact with the plurality of resin particles, forming second fibers from the plurality of resin particles, the second fibers each having an outer diameter that is smaller than each of the first fibers and is set to a value in a range of <NUM> or greater to <NUM> or less, and forming a fiber composite including the first fibers and the second fibers.

According to the method described above, by performing the aforementioned steps, a bulky fiber article can be produced that includes the fine second fibers each having an outer diameter set to a value in the range of <NUM> or greater to <NUM> or less, and the first fibers each having an outer diameter larger than that of the second fiber. Further, the fine second fibers are combined with the first fibers, and the second fibers are supported by the first fibers. Therefore, compared to a case where a fiber article is produced only from resin fibers, for example, a bulky fiber article can be produced. In addition, a fiber article that can achieve the function of the second fibers over a long period of time can be produced. Furthermore, for example, the second fibers are formed of the plurality of resin particles dispersedly brought into contact with the first fibers, and thus the second fibers can be uniformly distributed and disposed within the fiber article and a fiber article having uniform quality can be produced.

In addition, by performing the steps described above, the fiber article can be efficiently and sequentially produced with the use of a single transfer facility. Therefore, a separate step of forming the second fibers can be omitted, and production steps are simplified and thus production costs can be reduced. As a result, a bulky fiber article having high functionality can be efficiently produced.

In the first processing step, a band may be formed by applying the external force to the first fibers to which the plurality of resin particles is added and crimping the first fibers. Consequently, the fiber article including the first fibers and the second fibers can be efficiently produced while using the band.

In the first processing step, while transferring the band, tensile force may be applied as the external force in a transfer direction to the plurality of first fibers brought into contact with the plurality of resin particles in the band. Additionally, in the first processing step, the plurality of first fibers may be inserted between a pair of nip rolls and pressed by the pair of nip rolls, whereby the external force is applied to the first fibers brought into contact with the plurality of resin particles. As a result, in the first processing step, the external force can be efficiently applied to the first fibers.

In the contact step, a dispersion in which the plurality of resin particles are dispersed may be used. By using the dispersion as just described, fluidity of the dispersion can be used to easily bring the plurality of resin particles into contact with a wide range of the surface of the first fibers.

The method may further include a drying step of, between the contact step and the first processing step, drying at least a portion of the dispersion applied to the first fibers. Therefore, by drying a portion of the dispersion before forming the band, the amount of the resin particles that drop from the first fibers can be reduced, and the weight ratio between the first fibers and the second fibers can be easily adjusted. Additionally, the resin particles are appropriately brought into contact with the first fibers, and thus formation of the second fibers in the second processing step can be facilitated.

An aqueous dispersion obtained by dispersing the plurality of resin particles in water may be used as the dispersion. As a result, the dispersion can be produced at relatively low cost and the dispersion can be easily handled.

In the contact step, the dispersion separated from the first fibers in the first processing step may be reused. Therefore, a reduction in the production costs can be further facilitated.

In the contact step, the plurality of resin particles in a powder form may be directly brought into contact with the first fibers. As a result, the plurality of resin particles can be brought into contact with the first fibers in a relatively simple manner.

In the first processing step, nip pressure set to a value of <NUM> MPa or greater may be applied as the external force to the plurality of first fibers brought into contact with the plurality of resin particles. By setting the nip pressure as just described, the second fibers can be appropriately and easily formed.

In the contact step, the plurality of resin particles including lamellar structures may be used. Therefore, in the second processing step, the second fibers can be easily formed from the plurality of resin particles.

In the second processing step, the fiber composite may be formed in which a weight ratio W1/W2 of a total weight W1 of the first fibers to a total weight W2 of the second fibers and the residual resin particles is set to a value in a range of <NUM> or greater to <NUM> or less. As a result, the second fibers can be stably supported on a support body formed of the first fibers, and thus the function of the second fibers can be easily achieved.

In the second processing step, a length dimension of the first fibers may form the fiber composite that is longer than a length dimension of the second fibers. As a result, for example, the first fibers are used as the framework of the fiber article and the second fibers are supported on the first fibers, and thus the function of the second fibers can be stably achieved.

In the contact step, the first fibers each having an outer diameter set to a value in a range of <NUM> or greater and <NUM> or less may be used. As a result, design flexibility of the fiber article can be improved.

In the contact step, the first fibers formed of at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, or cellulose acetate may be used. Additionally, in the contact step, the resin particles formed of polytetrafluoroethylene are used.

According to the method described above, the fiber article including the first fibers and the second fibers can be efficiently produced, and the first fibers and the second fibers respectively formed of specific materials are combined, and thus the functions of the first fibers and the second fibers can be easily achieved.

According to aspects of the present disclosure, in a case where a fiber article is produced by combining different types of fibers having different outer diameters, a bulky fiber article having high functionality can be efficiently produced.

A production method for a fiber article according to a first embodiment includes: a contact step of, while transferring a plurality of first fibers, bringing a plurality of resin particles formed of PTFE that can be fiberized into contact with the plurality of first fibers; a first processing step of applying an external force to the plurality of first fibers brought into contact with the plurality of resin particles and narrowing gaps between fibers; and a second processing step of, by relieving the external force applied to the plurality of first fibers brought into contact with the plurality of resin particles, forming second fibers from the plurality of resin particles, the second fibers each having an outer diameter that is smaller than each of the first fibers and is set to a value in a range of <NUM> or greater to <NUM> or less, and forming a fiber composite including the first fibers and the second fibers. In order to perform the first processing step, in the present embodiment, the plurality of first fibers are crimped, and thus external force is applied to the plurality of first fibers. A band production apparatus and a fiber article production apparatus that are used in the production method will be described below.

<FIG> is an overall view of a band production apparatus <NUM> according to the first embodiment. The band production apparatus <NUM> illustrated in <FIG> spins filaments <NUM> as first fibers by dry spinning. Further, the band production apparatus <NUM> produces a yarn <NUM>, an end <NUM>, and a band <NUM> from a plurality of the filaments <NUM>. The raw material of the filament <NUM> may be any material from which the yarn <NUM>, the end <NUM>, and the band <NUM> are appropriately obtained, for example, in the spinning method to be selected. The filament <NUM> of the present embodiment includes at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, or cellulose acetate. As an example, the filament <NUM> is made of cellulose acetate.

The band production apparatus <NUM> is provided with a mixing apparatus <NUM>, a filtration apparatus <NUM>, a spinning unit <NUM>, lubrication units <NUM>, godet rolls <NUM>, guide pins <NUM>, an application apparatus <NUM>, a first drying apparatus <NUM>, a crimping apparatus <NUM>, and a second drying apparatus <NUM>.

In the band production apparatus <NUM>, a predetermined spinning dope <NUM> is used. As an example, the spinning dope <NUM> is formed by dissolving flakes made of, for example, cellulose diacetate in an organic solvent at a predetermined concentration. During driving of the band production apparatus <NUM>, the spinning dope <NUM> is mixed by the mixing apparatus <NUM> and then filtered by the filtration apparatus <NUM>. The spinning dope <NUM> passed through the filtration apparatus <NUM> is extruded from a plurality of orifices 15a of a spinneret <NUM> provided on a cabinet <NUM> of the spinning unit <NUM>.

The orifice 15a has a circumference shape formed into a predetermined shape (for example, a circular shape). The diameter of each orifice 15a is set as appropriate in accordance with a denier per filament (FD) of the produced filaments <NUM>. The spinning dope <NUM> extruded from each orifice 15a is heated by hot air supplied from a drying unit (not illustrated) into the cabinet <NUM> and the organic solvent evaporates, and thus the spinning dope <NUM> is dried. As a result, the solid filaments <NUM> are formed.

As illustrated in <FIG>, the plurality of filaments <NUM> passed through the single cabinet <NUM> are gathered by the guide pins <NUM>, thereby forming the yarn <NUM>. After the lubricant is applied by the lubrication unit <NUM>, the yarn <NUM> is wound by the godet roll <NUM>. The yarn <NUM> is then taken up by a predetermined winding device.

The series of units for producing the yarn <NUM>, i.e., the spinning unit <NUM> that extrudes the spinning dope <NUM> from the spinneret <NUM> and spins the filaments <NUM>, the drying unit, the lubrication unit <NUM>, and the winding unit that includes the godet rolls <NUM>, is collectively referred to as a station. Typically, a plurality of stations are arranged in a line.

A plurality of yarns <NUM> passed through each station is transferred along the arrangement direction of the stations and sequentially accumulated or layered. With this configuration, the plurality of yarns <NUM> are layered to form the end (a tow) <NUM>, which is a flat assembly of the yarns <NUM>. The end <NUM> is formed by layering the plurality of yarns <NUM> and setting the yarns to a predetermined total denier (TD). The end <NUM> is transferred and guided to the application apparatus <NUM>.

Note that the method for spinning the filaments <NUM> 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 method for spinning the filaments <NUM> may be any method provided that the band <NUM> is appropriately obtained.

The application apparatus <NUM> applies a dispersion including resin particles <NUM> to the filaments <NUM> while transferring a plurality of first fibers (here, the end <NUM>). For example, the application apparatus <NUM> includes a reservoir that stores the dispersion, and an affixing roll that is pivotally supported such that the dispersion in the reservoir is applied to the roll surface to be applied to the filaments <NUM>. The dispersion of the present embodiment is an aqueous dispersion obtained by dispersing the plurality of resin particles <NUM> in water. The dispersion may include a liquid other than water.

The resin particle <NUM> internally includes a lamellar structure. The lamellar structure herein corresponds to a structure in which polymer chains constituting a resin of the resin particles <NUM> are linked and folded. The lamellar structure internally included in the resin particles <NUM> comprises fine fibers, specifically, in which millions of the polymer chains are linked and formed into a ribbon shape. The fine fibers are folded and stored in the resin particles <NUM>.

The resin particles <NUM> are primary particles, and the plurality of resin particles <NUM> bond to each other to form secondary particles. When an external force is applied to the secondary particles (in other words, two bonded resin particles <NUM>) such that the resin particles <NUM> are separated, the fine fibers are drawn out of the resin particles <NUM>, and resin fibers 66a are formed from the resin particles <NUM>. In the dispersion of the present embodiment, the primary particles formed of the plurality of resin particles <NUM> are contained in a dispersed manner in the solvent. The application apparatus <NUM> applies the dispersion to the filaments <NUM>, and thus the plurality of resin particles <NUM> are dispersedly brought into contact with the surface of the filaments <NUM>. The external force is applied to the plurality of filaments <NUM> to narrow gaps between fibers, and thus the plurality of resin particles <NUM> brought into contact with the surface of the different filaments <NUM> adhere to each other. In addition, the external force applied to the plurality of filaments <NUM> is relieved, and thus the adhered resin particles <NUM> are separated and the resin fibers 66a are formed.

The resin particles <NUM> of the present embodiment may be formed, for example, by a polymerization reaction and may contain lamellar structures. The resin particles <NUM> are made of PTFE (polytetrafluoroethylene).

Here, the resin particles <NUM> are set to have a mean particle size of a value in a range of <NUM> or greater to <NUM> or less (for example, approximately <NUM>). As an example, the value of the mean particle size is further preferably in a range of <NUM> or greater to <NUM> or less, and is still further preferably in a range of <NUM> or greater to <NUM> or less. Note that the mean particle size refers to the median diameter (cumulative <NUM>% diameter (D50)) calculated from measurement results of dynamic light scattering. The resin particles <NUM> are formed, for example, by paste extrusion.

The first drying apparatus <NUM> dries at least a portion of the dispersion applied to the filaments <NUM>. The crimping apparatus <NUM> crimps the filaments <NUM>. As an example, the crimping apparatus <NUM> includes a pair of nip rolls N1, N2 and a stuffing box <NUM>. Rotating shafts of the pair of nip rolls N1, N2 are arranged in parallel to each other. The pair of nip rolls N1, N2 press the end <NUM> between the roll surfaces of the respective rolls.

The stuffing box <NUM> is disposed on a rear side of the pair of nip rolls N1, N2 in a transfer direction P. The stuffing box <NUM> includes a pair of plate members C1, C2 each having a plate surface extending in the transfer direction P, and a biasing member <NUM>. The pair of plate members C1, C2 are disposed with the plate surfaces facing each other across a gap G and with the gap G decreasing from a front side to a rear side of the stuffing box <NUM> in the transfer direction P. The end <NUM> (the plurality of filaments <NUM>) passed through the pair of nip rolls N1, N2 is transferred in the gap G.

The biasing member <NUM> is a plate member as an example, and extends in a direction perpendicular to the transfer direction P along the plate surface of the plate member C <NUM>. A front end of the biasing member <NUM> in the transfer direction P is supported by the plate member C1 to be rotatable about an axis Q extending in the direction perpendicular to the transfer direction P along the plate surface of the plate member C1. The biasing member <NUM> is biased toward the plate surface of the plate member C2 and presses the end <NUM> transferred between the pair of plate members C1, C2.

The end <NUM> is pressed between the pair of nip rolls N1, N2 by the pair of nip rolls N1, N2 and is thereafter pushed into the stuffing box <NUM>. The end <NUM> is pressed against the plate surface of the plate member C2 by the biasing member <NUM> while being transferred in a meandering manner between the plate surfaces of the plate members C1, C2. The end <NUM> is pushed into the stuffing box <NUM> by the pair of nip rolls N1, N2 by a force larger than a force applied to the end <NUM> from the plate members C1, C2 and the biasing member <NUM>, and thus crimping is applied to the end <NUM>. The end <NUM> passes through the crimping apparatus <NUM>, thereby forming the band <NUM>. Further, the plurality of filaments <NUM> in the end <NUM> are pressurized in the crimping apparatus <NUM>. As a result, the gaps between fibers are narrowed and the plurality of resin particles <NUM> that have been brought into contact with the filaments <NUM> bond together. As a result, the secondary particles of the resin particles <NUM> are formed.

In the crimping apparatus <NUM>, nip pressure of the pair of nip rolls N1, N2 is desirably set to a value in a suitable pressure range in order to appropriately crimp the filaments <NUM> and reduce the amount of dropping of the dispersion from the filaments <NUM>. The band <NUM> passed through the crimping apparatus <NUM> is further dried by the second drying apparatus <NUM>.

<FIG> is a schematic cross-sectional view of the band <NUM> produced by the band production apparatus <NUM> of <FIG>. As illustrated in <FIG>, the band <NUM> includes the plurality of crimped filaments <NUM> and the plurality of resin particles <NUM> dispersed into the band <NUM> and supported on the filaments <NUM>. The surface of the filaments <NUM> is partially covered by the plurality of resin particles <NUM>. The plurality of resin particles <NUM> are supported on the filaments <NUM> while being bonded together. By using the crimped filaments <NUM>, the band <NUM> is formed to be bulky.

The TD and FD of the band <NUM> may be set as appropriate. The FD of the band <NUM> is set to a value in a range of, for example, <NUM> or greater to <NUM> or less. From the perspective of appropriately securing the gaps between fibers while retaining appropriate strength of the filaments <NUM>, it is desirable that the FD of the band <NUM> is further set to a value in a range of <NUM> or greater to <NUM> or less. As illustrated in <FIG>, the band <NUM> passed through the second drying apparatus <NUM> is accumulated and then pressurized and packaged in a packaging container <NUM>, thereby forming a bale shape. <FIG> illustrates a cross-sectional structure of the packaging container <NUM>.

Next, the PTFE used as the material of the resin particles <NUM> will be described. The PTFE is configured as high molecules that can be fiberized. Such PTFE is high molecular weight PTFE obtained from, for example, emulsion polymerization or suspension polymerization of TFE (tetrafluoroethylene). The high molecular weight PTFE may be at least any of modified PTFE or homo PTFE.

The modified PTFE consists of TFE and a monomer (modified monomer) other than TFE. Typically, the modified PTFE is uniformly denatured by the modified monomer or is denatured at the early or end stage of a polymerization reaction, but the modified PTFE is not particularly limited. The modified PTFE includes a TFE unit based on TFE and a modified monomer unit based on a modified monomer.

In addition, the modified monomer unit is a part of a molecular structure of the modified PTFE, and is a part derived from the modified monomer. The total monomer unit is derived from all monomers in the molecular structure of the modified PTFE. As long as the modified monomer can be copolymerized with TFE, the modified monomer is not particularly limited.

Herein, "high molecular weight" of the high molecular weight PTFE refers to a molecular weight at which the PTFE is easily fiberized at the time of producing the band <NUM> and at which fibrils having a long fiber length are obtained. The high molecular weight is a value of a standard specific gravity (SSG) in a rage of <NUM> or greater and <NUM> or less, and indicates a molecular weight at which melt flow substantially does not occur due to high viscosity. Note that, for information regarding PTFE that can be fiberized, for example, <CIT> can be referred to.

<FIG> is an overall view of a fiber article production apparatus <NUM> according to the first embodiment. <FIG> illustrates a cross-sectional structure of the packaging container <NUM>. As illustrated in <FIG>, the fiber article production apparatus <NUM> includes a layering ring <NUM>, a first filament opening unit <NUM>, a turn baffle <NUM>, a second filament opening unit <NUM>, a pair of pre-tension rolls <NUM>, a pair of first filament opening rolls <NUM>, a pair of second filament opening rolls <NUM>, a third filament opening unit <NUM>, a pair of transfer rolls <NUM>, and a winding roll <NUM>.

The layering ring <NUM> and the turn baffle <NUM> guide the bale-shaped band <NUM> fed up from within the packaging container <NUM> toward the first filament opening unit <NUM>. The first filament opening unit <NUM>, the second filament opening unit <NUM>, and the third filament opening unit <NUM> open the band <NUM> in the width direction of the band <NUM> by using gas (for example, pressurized air). The pair of pre-tension rolls <NUM>, the pair of first filament opening rolls <NUM>, and the pair of second filament opening rolls <NUM> open the band <NUM> in the width direction and the transfer direction P in a state where the band <NUM> is subject to tensile force in the transfer direction P.

The pair of pre-tension rolls <NUM> include a pair of rolls R1, R2 arranged with the roll surfaces facing each other. The pair of first filament opening rolls <NUM> include a pair of rolls R3, R4 arranged with the roll surfaces facing each other. The pair of second filament opening rolls <NUM> include a pair of rolls R5, R6 arranged with the roll surfaces facing each other. Grooves extending in a circumferential direction are formed on the roll surfaces of the rolls R3 to R6 and are configured to easily open the band <NUM>.

The pair of transfer rolls <NUM> include a pair of rolls R7, R8 arranged with the roll surfaces facing each other. The pair of transfer rolls <NUM> transfer the band <NUM> passed through the pair of second filament opening rolls <NUM> to the winding roll <NUM> side. The winding roll <NUM> winds the band <NUM> passed through the pair of transfer rolls <NUM>.

During driving of the fiber article production apparatus <NUM>, the band <NUM> fed up from within the packaging container <NUM> is inserted through the layering ring <NUM> and is thereafter opened in the width direction by the first filament opening unit <NUM>. Afterward, the band <NUM> is guided by the turn baffle <NUM> toward the second filament opening unit <NUM>.

Next, the band <NUM> is further opened in the width direction by the second filament opening unit <NUM> and is thereafter sequentially inserted between the rolls R1, R2, between the rolls R3, R4, and between the rolls R5, R6. The band <NUM> makes contact with the rolls R1 to R6. The rotating speed of the pair of rolls R5, R6 is higher than the rotating speed of the pair of rolls R3, R4. Therefore, the band <NUM> is opened in the transfer direction P and the width direction while being subject to tensile force in the transfer direction P by the pair of first filament opening rolls <NUM> and the pair of second filament opening rolls <NUM>.

Here, <FIG> is a schematic cross-sectional view of the band <NUM> transferred between the pair of first filament opening rolls <NUM> and the pair of second filament opening rolls <NUM> of <FIG>. As illustrated in <FIG>, the band <NUM> is opened in the transfer direction P (the left-right direction on the plane of paper) and the width direction (the direction perpendicular to the plane of paper) by the pair of rolls <NUM>, <NUM>, and thus the tensile force acts on the filaments <NUM> and the resin particles <NUM> in the transfer direction P and the width direction. As a result, the plurality of filaments <NUM> in the band <NUM> are opened.

At this time, the tensile force (stretching force) acts on the resin particles <NUM> to separate the resin particles <NUM> bonded to each other, and thus the fine fibers folded in the resin particles <NUM> are efficiently elongated and the resin fibers 66a are formed. Therefore, the band <NUM> is formed into a fiber composite <NUM> including the filaments <NUM> and the resin fibers 66a.

As just described, in the present embodiment, the resin fibers 66a can be formed by opening the plurality of filaments <NUM> in the band <NUM> and using the tensile force applied to the band <NUM> during opening. Therefore, a dedicated process or equipment for separately forming the resin fibers 66a is not required.

Here, the resin fibers 66a are formed at the time of opening the band <NUM>; however, the resin fibers 66a are formed by applying an external force to narrow the gaps between fibers with respect to the plurality of filaments <NUM> to which the plurality of resin particles <NUM> are brought into contact, and then relieving the external force. In the present embodiment, the dispersion is applied to the plurality of filaments <NUM> by the application apparatus <NUM> and then the external force is applied at least once. Thereafter, the external force is relieved, and the resin fibers 66a are formed. Thus, the resin fibers 66a can be also formed, for example, by applying nip pressure as the external force to the plurality of filaments <NUM> brought into contact with the plurality of resin particles <NUM>, by at least any of the pair of nip rolls N1, N2, the pair of first filament opening rolls <NUM>, and the pair of second filament opening rolls <NUM>. In order to form the resin fibers 66a, for example, at least one of the external forces described above may be used.

The outer diameter of the resin fiber 66a can be adjusted by, for example, the tensile force applied to the band <NUM> at the time of opening the band <NUM>. For example, when the tensile force is increased, the outer diameter of the resin fiber 66a can be set to be small and the length dimension of the resin fiber 66a can be set to be long. When the tensile force is decreased, the outer diameter of the resin fiber 66a can be set to be large and the length dimension of the resin fiber 66a can be set to be short.

With such an adjustment, in the present embodiment, the outer diameter of the resin fiber 66a can be set to a value in a range of <NUM> or greater to <NUM> or less. As illustrated in <FIG>, the fiber composite <NUM> passed between the pair of second filament opening rolls <NUM> is inserted between the rolls R7, R8 of the pair of transfer rolls <NUM>. The rotating speed of the pair of rolls R7, R8 is slower than the rotating speed of the pair of rolls R5, R6. Therefore, the tensile force applied to the fiber composite <NUM> in the transfer direction P between the pair of first filament opening rolls <NUM> and the pair of second filament opening rolls <NUM> is relieved between the pair of second filament opening rolls <NUM> and the pair of transfer rolls <NUM>. Relieving this tensile force adjusts the fiber composite <NUM> to be bulky.

The fiber composite <NUM> passed through the pair of transfer rolls <NUM> is wound on the winding roll <NUM>. The fiber composite <NUM> is cut to a predetermined length dimension, and thus a fiber article <NUM> is produced. <FIG> is a cross-sectional view of the fiber article <NUM> produced by the fiber article production apparatus <NUM> of <FIG>.

As illustrated in <FIG>, within the fiber article <NUM>, the resin fibers 66a are supported on the filaments <NUM> while being intertwined with the filaments <NUM>. Accordingly, even when the resin fiber 66a is thinner than the filament <NUM>, the resin fibers 66a can be supported on the filaments <NUM> while the resin fibers 66a are prevented from being cut. Therefore, the function of the resin fibers 66a can be maintained over a long period of time. The resin fibers 66a are dispersedly disposed throughout the inside of the band <NUM>. Note that a portion of the resin particles <NUM> may be decreased in size or may be exhausted within the fiber article <NUM> in accordance with forming of the resin fibers 66a.

The fiber article <NUM> is formed bulkier by the plurality of filaments <NUM> that are opened with abundant gaps between fibers therein. Therefore, the fiber article <NUM> has an appropriate airy texture. The fiber article <NUM> is formed into a sheet-like article as an example. Note that the fiber article <NUM> may be formed by overlaying and crimping a plurality of sheet-like fiber composites <NUM>. In this case, for example, the thickness dimension of the fiber article <NUM> can be easily designed by adjusting the number of fiber composites <NUM>. Additionally, the fiber article <NUM> may be formed with the plurality of sheet-like fiber composites <NUM> arranged side by side in the width direction. In this case, for example, the width dimension of the fiber article <NUM> can be easily designed by adjusting the number of the fiber composites <NUM>.

The value of the external force applied to the plurality of filaments <NUM> to form the resin fibers 66a can be set as appropriate, but may be a value of, for example, <NUM> MPa or greater. When the fiber article <NUM> is used in filtration, the value of the external force applied to the plurality of filaments <NUM> is desirably a value of, for example, <NUM> MPa or greater in order to obtain good filter performance. Note that the upper limit of the external force may be a value of, for example, <NUM> MPa or greater (e.g., several tens of MPa or greater).

As described above, the fiber article <NUM> is produced by a production method using the band production apparatus <NUM> and the fiber article production apparatus <NUM>. The production method includes a contact step, a first processing step, and a second processing step. The production method of the present embodiment further includes a drying step.

The contact step is a step of bringing the plurality of resin particles <NUM> formed of PTFE that can be fiberized (in the present embodiment, the dispersion that includes the plurality of resin particles <NUM> containing lamellar structures and connected to each other) into contact with the filaments <NUM> while transferring the plurality of filaments <NUM>. The first processing step is a step of applying an external force to the plurality of filaments <NUM> brought into contact with the plurality of resin particles <NUM>, and narrowing the gaps between fibers.

Further, in the first processing step of the present embodiment, the external force is applied to the filaments <NUM> to which the plurality of resin particles <NUM> are added and the filaments <NUM> are crimped, and thus the band <NUM> is formed. Furthermore, for example, in the first processing step, while transferring the band <NUM>, tensile force is applied as the external force in the transfer direction P to the plurality of filaments <NUM> in the band <NUM> brought into contact with the plurality of resin particles <NUM>.

Additionally, in the first processing step of the present embodiment, for example, nip pressure set to a value of <NUM> MPa or greater is further applied as the external force to the plurality of filaments <NUM> brought into contact with the plurality of resin particles <NUM>. The nip pressure is applied, for example, by at least any (here, by all) of the pair of nip rolls N1, N2, the pair of first filament opening rolls <NUM>, and the pair of second filament opening rolls <NUM>. As a result, the resin fibers 66a are abundantly formed.

The second processing step is a step of forming the resin fibers 66a from the plurality of resin particles <NUM> by relieving the external force applied to the plurality of filaments <NUM> brought into contact with the resin particles <NUM>, and forming the fiber composite <NUM> including the filaments <NUM> and the resin fibers 66a.

The drying step is a step of, between the contact step and the first processing step, drying at least a portion of the dispersion applied to the filaments <NUM>. In the present embodiment, for example, the dispersion separated from the filaments <NUM> in the first processing step is recovered, and the recovered dispersion is used in the contact step.

In addition, in the fiber composite <NUM>, a weight ratio W1/W2 of a total weight W1 of the filaments <NUM> and a total weight W2 of the resin fibers 66a and the residual resin particles <NUM> can be set as appropriate. In the second processing step of the present embodiment, the fiber composite <NUM> in which, for example, the weight ratio W1/W2 is set to a value in a range of <NUM> or greater to <NUM> or less is formed. As a result, in the fiber article <NUM>, the resin fibers 66a can be stably supported on a support body formed of the filaments <NUM>, and thus the function of the resin fibers 66a can be easily achieved. As another preferable example, the weight ratio W1/W2 may include a value in a range of <NUM> or greater to <NUM> or less. In a case where the resin particles <NUM> are formed of PTFE, a value in the range of the weight ratio W1/W2 corresponds to a value in a range of <NUM>% or greater to <NUM>% or less of the application concentration of PTFE in the fiber composite <NUM>. Additionally, in the contact step, the filaments <NUM> each having an outer diameter set to a value in a range of <NUM> or greater to <NUM> is used. As a result, design flexibility of the fiber article can be improved.

Note that by setting the weight ratio W1/W2 to a value in the range described above, a volume ratio V1/V2 of a total volume V1 of the filaments <NUM> (first fibers) to a total volume V2 of the resin fibers 66a (second fibers) and the residual resin particles <NUM> has a maximum value of <NUM> or less. As a result, the function of the resin fibers 66a can be easily achieved while the gaps between fibers inside of the fiber article <NUM> are appropriately maintained and the resin fibers 66a are stably held by the filaments <NUM>.

Moreover, the length dimension of the filaments <NUM> and the length dimension of the resin fibers 66a can be set as appropriate. In the second processing step of the present embodiment, the length dimension of the filaments <NUM> forms the fiber composite <NUM> that is longer than the length dimension of the resin fibers 66a. As a result, for example, the filaments <NUM> are used as the framework of the fiber article <NUM> and the resin fibers 66a are supported on the filaments <NUM>, and thus the function of the resin fibers 66a can be stably achieved.

As described above, according to the production method of the present embodiment, by performing the aforementioned steps, the bulky fiber article <NUM> can be produced that includes the fine resin fibers 66a each having an outer diameter set to a value in the range of <NUM> or greater to <NUM> or less, and the filaments <NUM> each having an outer diameter larger than that of the resin fiber 66a. Further, the fine resin fibers 66a are combined with the filaments <NUM>, and the resin fibers 66a are supported by the filaments <NUM>. Therefore, compared to a case where a fiber article is produced only from resin fibers, for example, the bulky fiber article <NUM> can be produced and the function of the resin fibers 66a in the fiber article <NUM> can be achieved over a long time. Furthermore, for example, the resin fibers 66a are formed of the plurality of resin particles <NUM> dispersedly brought into contact with the filaments <NUM>, and thus the resin fibers 66a can be uniformly distributed and disposed within the fiber article <NUM> and the fiber article <NUM> having uniform quality can be produced.

In addition, by performing the steps described above, the fiber article <NUM> can be efficiently and sequentially produced with the use of a single transfer facility. Therefore, a separate step of forming the resin fibers 66a can be omitted, and production steps are simplified and thus production costs can be reduced. As a result, the bulky fiber article <NUM> having high functionality can be efficiently produced.

In the related art, to produce a bulky fiber article, for example, needle-punching a fiber sheet made of short fibers and laminating a plurality of the fiber sheets to form a laminate are required. In the present embodiment, these processes are not required. Further, according to the present embodiment, the fiber article <NUM> having both a good bulkiness and a void ratio, which has been difficult to achieve in the prior art, can be produced relatively simply and efficiently. Furthermore, according to the present embodiment, the bulky fiber article <NUM> including fine fibers each having an outer diameter of <NUM> or less, which has been difficult to stably mass-produce in the prior art, can be appropriately produced.

Further, in the first processing step of the present embodiment, the external force is applied to the filaments <NUM> to which the plurality of resin particles <NUM> are added, thereby crimping the filaments <NUM>. Therefore, the band <NUM> is formed. Consequently, the fiber article <NUM> including the filaments <NUM> and the resin fibers 66a can be efficiently produced while using the band <NUM>.

Also, as an example, in the first processing step, tensile force is applied as the external force in the transfer direction to the band <NUM> while transferring the band <NUM>. Therefore, in the first processing step, the external force can be efficiently applied to the filaments <NUM>.

Furthermore, in the contact step of the present embodiment, the dispersion in which the plurality of resin particles <NUM> are dispersed is used. By using the dispersion as just described, fluidity of the dispersion can be utilized to easily bring the plurality of resin particles <NUM> into contact with a wide range of the surface of the filaments <NUM>.

In addition, since the production method includes the drying step, by drying a portion of the dispersion before forming the band <NUM>, the amount of the resin particles <NUM> that drop from the filaments <NUM> can be reduced, and the weight ratio between the filaments <NUM> and the resin fibers 66a can be easily adjusted. Further, the resin particles <NUM> are appropriately brought into contact with the filaments <NUM>, and thus the formation of the resin fibers 66a in the second processing step can be facilitated.

Furthermore, since an aqueous dispersion obtained by dispersing the plurality of resin particles <NUM> in water is used as the dispersion, the dispersion can be produced at relatively low cost and the dispersion can be easily handled. Further, the dispersion separated from the filaments <NUM> in the first processing step is reused in the contact step, and therefore a reduction in the production costs can be further facilitated.

Furthermore, in the first processing step, as an example, nip pressure set to a value of <NUM> MPa or greater is applied as the external force to the plurality of filaments <NUM> brought into contact with the plurality of resin particles <NUM>. By setting the nip pressure as just described, the resin fibers 66a can be appropriately and easily formed.

Additionally, in the contact step, the plurality of resin particles <NUM> including lamellar structures are used. Therefore, in the second processing step, the resin fibers 66a can be easily formed from the plurality of resin particles <NUM>.

In the contact step, the filaments <NUM> formed of at least one of rayon, polypropylene, polyethylene terephthalate, polyethylene, or cellulose acetate may be used. Also, in the contact step, the resin particles <NUM> formed of polytetrafluoroethylene are used.

According to the method described above, the fiber article <NUM> including the filaments <NUM> and the resin fibers 66a can be efficiently produced, and the filaments <NUM> and the resin fibers 66a respectively formed of specific materials are combined, and thus the functions of the filaments <NUM> and the resin fibers 66a can be easily achieved.

Note that in the first processing step, the external force applied to the plurality of filaments <NUM> may be a force applied to the plurality of filaments <NUM> at a timing other than the timing of crimping the filaments <NUM> or opening the band including the crimped filaments <NUM>.

<FIG> is a schematic diagram of a band production apparatus <NUM> according to a modified example of the first embodiment. As illustrated in <FIG>, in the band production apparatus <NUM>, the application apparatus <NUM> and the first drying apparatus <NUM> are omitted, and in place of these, the band production apparatus <NUM> includes a particle adding apparatus (feeder) <NUM>. The particle adding apparatus <NUM> is disposed at the cabinet <NUM> side rather than at the crimping apparatus <NUM> (here, between the godet rolls <NUM> and the crimping apparatus <NUM> in the transfer direction P) such that the resin particles <NUM> in a powder form can be added to the filaments <NUM>.

By using such a band production apparatus <NUM>, the plurality of resin particles <NUM> in a powder form are directly applied to the filaments <NUM> in the contact step of the present modified example. Here, water or a fiber oil agent is usually applied to the filaments <NUM> to be introduced into the crimping apparatus <NUM>. Therefore, the resin particles <NUM> appropriately adhere to the surface of the filaments <NUM>. According to this method, the plurality of resin particles <NUM> can be brought into contact with the filaments <NUM> in a relatively simple manner. Hereinafter, a second embodiment will be described focusing on differences from the first embodiment.

<FIG> is a schematic view of a fiber article production apparatus <NUM> according to a second embodiment. In the present embodiment, a bale-like band <NUM> that does not include the resin particles <NUM> and is not crimped is used. The band <NUM> is compressed and packaged in a packaging container <NUM>.

As illustrated in <FIG>, the fiber article production apparatus <NUM> includes a plurality of guide members (for example, guide rolls R9 to R16) dispersedly disposed to guide the band <NUM> fed from the packaging container <NUM> in the transfer direction P, an application apparatus <NUM> that applies a dispersion to the band <NUM> being transferred, a pair of nip rolls N4, N5 that causes the tow band <NUM> to which the dispersion is applied to pass through a nip point N3, and a drying apparatus <NUM> that dries the band <NUM> (fiber composite <NUM>) passed through the nip rolls N4, N5. Within the application apparatus <NUM>, the band <NUM> is guided by the guide roll R12 and immersed in the dispersion based on a dip coating method, thereby being applied with the dispersion. The band <NUM> to which the dispersion is applied by the application apparatus <NUM> and which is dried by the drying apparatus <NUM> is temporarily packaged in another packaging container <NUM>.

The fiber article production apparatus <NUM> also includes the first filament opening unit <NUM> that widens the band <NUM> fed from the packaging container <NUM>, a turn baffle <NUM> that guides the band <NUM>, the second filament opening unit <NUM> that widens the band <NUM> passed through the turn baffle <NUM>, and a pair of nip rolls N7, N8 that causes the band <NUM> passed through the second filament opening unit <NUM> to pass through a nip point N6.

According to the fiber article production apparatus <NUM>, the band <NUM> to which the plurality of resin particles <NUM> are brought into contact passes through the nip point N3 of the nip rolls N4, N5, and an external force (nip pressure) is applied to the plurality of filaments <NUM> to narrow the gaps between fibers. Also, thereafter, the external force applied to the filaments <NUM> is relieved. At this time, in the gaps between fibers, a large number of the resin particles <NUM> are dispersed and brought into contact with the surface of the plurality of filaments <NUM>, and the gaps between fibers are narrowed by the external force. Thereby, the resin particles <NUM> brought into contact with the surfaces of different filaments <NUM> are bonded together.

Afterward, the external force is relieved and the gaps between fibers are again enlarged, and thus the bonded resin particles <NUM> are separated from each other. As a result, the resin fibers 66a are formed from the resin particles <NUM> brought into contact with the filaments <NUM> of the band <NUM>, and the fiber composite <NUM> is formed. The resin fibers 66a are also formed by passing the band <NUM> through the nip point N6 of the nip rolls N7, N8. The fiber composite <NUM> is wound on the predetermined winding roll <NUM>. The wound fiber composite <NUM> is cut to predetermined dimensions, and thus the fiber article <NUM> is obtained.

As described above, in the production method for the fiber article <NUM> of the present embodiment, in the first processing step, the plurality of filaments <NUM> are inserted between the pair of nip rolls N4, N5 and pressed by the pair of nip rolls N4, N5, thereby applying the external force to the filaments <NUM> to which the resin particles <NUM> are brought into contact. Such a method can also efficiently produce the fiber article <NUM>. Also, according to the present embodiment, the fiber article <NUM> using the filaments <NUM> that are not crimped is obtained. Therefore, design flexibility of the fiber article <NUM> can be improved. Note that when the nip rolls N4, N5 and the nip rolls N7, N8 are used as in the present embodiment, for example, the nip rolls N7, N8 may be omitted.

A confirmation test was performed to confirm the numerical range of the external force that enables the resin fibers 66a to be formed in the first processing step. In the band production apparatus <NUM> of the first embodiment, the pressure (nip pressure) of the pair of nip rolls N1, N2 was changed in a range of <NUM> MPa or greater to <NUM> MPa or less. Additionally, in the fiber article production apparatus <NUM>, the pressure (nip pressure) of each of the pair of first filament opening rolls <NUM> and the pair of second filament opening rolls <NUM> was changed in a range of <NUM> MPa or greater to <NUM> MPa or less. Accordingly, the setting conditions of Examples <NUM> to <NUM> were prepared. In addition, Comparative Example <NUM> was prepared in which the pressure (nip pressure) of any of the pair of nip rolls N1, N2, the pair of first filament opening rolls <NUM>, and the pair of second filament opening rolls <NUM> was set to <NUM> MPa. The results are indicated in Table <NUM>.

As indicated in Table <NUM>, it was confirmed that the resin fibers 66a in Comparative Example <NUM> could not be formed, while it was confirmed that the resin fibers 66a in Examples <NUM> to <NUM> could be formed. Additionally, when the fiber article <NUM> of each of the Examples <NUM> to <NUM> was magnified and observed, it was confirmed that the fiber articles <NUM> of Examples <NUM> to <NUM> are formed such that the resin fibers 66a are abundantly distributed in a wide range compared to the fiber articles <NUM> of Examples <NUM> to <NUM>. As a result, it is believed that at the time of producing the fiber article <NUM>, the fiber article <NUM> including the resin fibers 66a abundantly formed and distributed in a wide range can be easily produced, for example, by performing the first processing step at a plurality of timings.

Note that each of the configurations, combinations thereof, or the like in each of the embodiments are examples, and additions, omissions, replacements, and other changes to the configurations may be made as appropriate without departing from the present disclosure. The present disclosure is not limited by the embodiments and is limited only by the claims. Also, the aspects disclosed in the present specification can be combined with any other feature disclosed herein.

In the first embodiment, packaging the band <NUM> produced by the band production apparatus <NUM>, <NUM> into the packaging container <NUM> is described. However, the fiber article <NUM> may be produced by introducing the band <NUM> into the fiber article production apparatus <NUM> without packaging the band <NUM>. Further, the configuration of the fiber article production apparatus <NUM> is not limited to that described above. Furthermore, a slurry containing a relatively large amount of the resin particles <NUM> may be used as the dispersion used in the contact step. Additionally, the resin particles <NUM> may be brought into contact with the filaments <NUM> prior to forming the yarn <NUM> or the end <NUM>.

Claim 1:
A production method for a fiber article (<NUM>), comprising:
a contact step of, while transferring a plurality of first fibers (<NUM>), bringing a plurality of resin particles (<NUM>) formed of polytetrafluoroethylene that can be fiberized into contact with the plurality of first fibers (<NUM>);
a first processing step of applying an external force to the plurality of first fibers (<NUM>) brought into contact with the plurality of resin particles (<NUM>), and narrowing gaps between fibers; and
a second processing step of, by relieving the external force applied to the plurality of first fibers (<NUM>) brought into contact with the plurality of resin particles (<NUM>), forming second fibers (66a) from the plurality of resin particles (<NUM>), the second fibers (66a) each having an outer diameter that is smaller than each of the first fibers (<NUM>) and is set to a value in a range of <NUM> or greater to <NUM> or less, and forming a fiber composite (<NUM>) including the first fibers (<NUM>) and the second fibers (66a).