JP7460271B2 - Nonwoven fabric manufacturing method and nonwoven fabric manufacturing device - Google Patents

Description

The present invention relates to a method for manufacturing nonwoven fabric and an apparatus for manufacturing nonwoven fabric.

Nonwoven fabrics are often used as components of absorbent articles because of their liquid permeability and pleasant texture. Techniques have been proposed to improve the physical properties of nonwoven fabrics used in absorbent articles.
For example, Patent Document 1 describes a shaping device equipped with a pair of upper and lower stretching rolls as a device for improving the softness and smoothness of nonwoven fabric. The upper stretching roll has a plurality of convex ridges provided at regular intervals in the roll width direction and parallel to each other along the outer circumferential surface of the roll. A concave groove is provided between adjacent convex ridges. The lower stretching roll has a plurality of pins provided on its outer circumferential surface so as to mesh with the concave grooves. These pins are arranged at regular intervals in the roll width direction so as not to come into contact with the convex ridges of the upper stretching roll, and are arranged approximately linearly at regular intervals along the outer circumferential surface.

JP 2016-123651 A

When forming unevenness on a fiber material by loosely inserting the convex portions of the concave and convex members of the concave and convex members disposed facing each other into the concave portions of the other party, as in the shaping device described in Patent Document 1, contact between the convex portions is prevented. This is necessary. By suitably inserting the protrusions loosely into the recesses without making them contact each other, the unevenness of the fibrous material (fiber web, nonwoven fabric, etc.) can be effectively formed, and unexpected damage to the fibrous material (such as holes and (cut) can be prevented.
However, contact between the convex portions may occur due to positional deviation in the width direction of the concavo-convex member. In the width direction of the uneven member, the space between the protrusions is often narrow, on the order of only a few millimeters, and if the above-mentioned positional deviation occurs during the uneven shaping process, it is difficult to correct it. A similar problem may also occur when uneven formation is performed with the uneven member and the net facing each other. In particular, the concavo-convex member and the net have different structures, and if they are made of different materials in addition to their structures, the above-mentioned positional deviation is more likely to occur.
Therefore, in shaping using a concavo-convex member and a net, it is required to control the position of the concave-convex member or the net in the width direction with high precision in millimeter units.

In view of the above-mentioned points, the present invention relates to a nonwoven fabric manufacturing method and a nonwoven fabric manufacturing apparatus that can suitably perform loose insertion between an opposing uneven member and a net when performing unevenness shaping.

The present invention provides a method for manufacturing a nonwoven fabric in which a fiber material is supplied between a support roll and a push-in net to form an uneven shape, and the support roll has convex portions and concave portions along the axial direction of the support roll. The push-in net has a concave and convex surface alternately arranged on its surface, and the push-in net has a width direction parallel to the axial direction and a longitudinal direction perpendicular to the width direction, and the push-in net has the convex and convex surfaces arranged alternately. A loosely inserted part into which the part is loosely inserted and a pushing part which is loosely inserted into the recess are arranged alternately along the width direction and the longitudinal direction, the pushing net is divided into a plurality of parts in the width direction, and the pushing part is loosely inserted into the recess. A method for manufacturing a nonwoven fabric, comprising loosely inserting the uneven surface and the pushing net in accordance with the rotation of the support roll, and interposing the fiber material between the uneven surface and the pushing net during the loose insertion. I will provide a.

The present invention also provides a nonwoven fabric manufacturing device that supplies fiber material between a support roll and a pressing net to form an uneven shape, the support roll having an uneven surface on its surface with convex and concave portions alternately arranged along the axial direction of the support roll, the pressing net having a width direction parallel to the axial direction and a longitudinal direction perpendicular to the width direction, the pressing net having loose insertion portions into which the convex portions are loosely inserted and pressing portions into which the concave portions are loosely inserted alternately arranged along the width direction and the longitudinal direction, and the pressing net is divided into a plurality of portions in the width direction.

The nonwoven fabric manufacturing method and nonwoven fabric manufacturing device of the present invention allow for optimal insertion of the opposing uneven members and the net when forming uneven surfaces.

1 is a cross-sectional view schematically showing a preferred embodiment of a nonwoven fabric manufacturing apparatus of the present invention. FIG. 2 is a partial perspective view showing a preferred example of a support roll surface of the manufacturing apparatus shown in FIG. 1. FIG. 3 is a partial cross-sectional view of the support roll shown in FIG. 2 . FIG. 13 is a perspective view showing an example of a state in which a pressing net and a support roll are partially engaged with each other. FIG. 3 is a partial cross-sectional view showing the arrangement relationship between the convex portions and concave portions of the support roll and the push-in net. 1 is a schematic front view showing a preferred example (first embodiment) of a push-in net. FIG. 13 is a schematic front view showing another preferred example (second embodiment) of the pushing net. FIG. 1A is a schematic front view showing another preferred example (third embodiment) of a push-in net, and FIG. 1B is a cross-sectional view showing said example.

EMBODIMENT OF THE INVENTION Hereinafter, the manufacturing apparatus which carries out the manufacturing method of the nonwoven fabric of this invention is demonstrated based on the preferable embodiment, referring to drawings.

As shown in FIG. 1, the nonwoven fabric manufacturing apparatus 1 of this embodiment includes a support roll 10 and a push-in net 21 that are arranged to face each other. A fiber material (not shown) is supplied between the support roll 10 and the push-in net 21 to form irregularities. The term "fibrous material" as used herein refers to an aggregate of fibers formed into a sheet, and includes, for example, nonwoven fabrics and fibrous webs. "Nonwoven fabric" refers to a fiber aggregate in which the fibers are bonded to each other at their intersections, or in which the fibers are entangled with each other so that they cannot be easily separated. For example, fibers are bonded together at their intersections by heat fusion or adhesive (thermal bond nonwoven fabric, resin bond nonwoven fabric, etc.), or fibers are intertwined with each other by the pressure of water flow (spunlace nonwoven fabric, etc.) including. A "fibrous web" refers to a fiber aggregate in a state before the fibers are bonded together, and is, so to speak, a material before being made into a nonwoven fabric.

The support roll 10 has an uneven surface on the surface 10S in which convex portions 11 and concave portions 12 are alternately arranged along the axial direction X1 of the support roll 10. The bottom surface of the recess 12 is the surface 10S of the support roll 10. Thereby, the support roll 10 is an uneven member having an uneven surface along the axial direction X1 on the surface 10S.
Further, it is preferable that the uneven surfaces of the surface 10S of the support roll 10 are arranged alternately not only in the axial direction X1 of the support roll 10 but also in the circumferential direction Y1. That is, as shown in FIGS. 2 and 3, the convex portions 11 are arranged at equal intervals in the axial direction X1 and the circumferential direction Y1 of the surface 10S of the support roll 10, and the concave portions 12 surround each convex portion 11 vertically and horizontally. It is preferable that they are arranged in a continuous grid pattern on the surface 10S of the support roll 10.

The support roll 10 may be drum-shaped. By drum-shaped, we mean a hollow cylindrical shape.

It is preferable that the support roll 10 has a plurality of openings (not shown) between the convex portions 11 that penetrate from the front surface 10S to the back surface. Due to the openings, wind can easily blow through the support roll 10, and it is possible to suppress the fibrous material from being disturbed or scattered. This makes it possible to suppress unevenness in the fiber material and make it homogenized, thereby making it possible to shape the fiber material while suppressing hardening. In addition, by blowing the wind through the support roll 10, it is easy to push the fiber material from the top of the convex portion 11 to the support roll 10, and a tall uneven shape can be made more clearly and efficiently shaped. Furthermore, the orientation of the fiber material along the wall surface of the convex portion 11 becomes more noticeable as the wind blows through. This makes it possible to efficiently produce a nonwoven fabric that is bulky and soft to the touch.

It is preferable that all the wall surfaces of the convex portions 11 are perpendicular to the surface 10S of the support roll 10. By using the support roll 10 in which the wall surface of the convex portion 11 is perpendicular to the surface 10S, it becomes possible to manufacture a nonwoven fabric that is bulkier and softer than before.
"All the wall surfaces of the convex portions 11 are perpendicular to the surface 10S of the support roll 10" means that any position on the wall surface is perpendicular to the surface 10S of the support roll 10. For example, when the convex portion 11 is a column with corners, such as a prism, each surface between the corners forming the wall surface is perpendicular to the surface 10S of the support roll 10. When the convex portion 11 is a columnar body without corners, such as a cylinder, it is said that the surface at any point of the curved surface constituting the wall surface is perpendicular to the surface 10S of the support roll 10.
"Perpendicular to the surface 10S of the support roll 10" means that the direction in which the wall surface is erected is perpendicular to the surface 10S of the support roll 10. For example, as shown in FIG. 3, when the surface 10S of the support roll 10 is an outwardly convex arc-shaped curved surface, the end face of the support roll 10 viewed from the side is located at the top of the wall surface on the support roll 10 side. This means that the angle θ formed by the outer line up to the side and the tangent J to the arc of the surface 10S at the width center point P of the convex portion 11 is perpendicular. In the present invention, it is preferable that the wall surface be in a "vertical" state as defined below, regardless of the cross section or end surface viewed from the side at any position of the convex portion 11.
"Perpendicular" means 88° or more and 92° or less with respect to the surface 10S of the support roll 10, preferably 89° or more, more preferably 89.5° or more, and preferably 91°. The angle is more preferably 90.5° or less.
The angle of the wall surface with respect to the surface 10S of the support roll 10 can be measured using MICURA manufactured by Tokyo Seimitsu Co., Ltd. The position of the surface 10S (flat or curved surface) of the support roll 10 is measured from five points other than the opening of the recess 12 in the direction perpendicular to the wall surface to be measured, and the position of the surface 10S of the wall surface is measured from three points in the height direction of the wall surface. Measure the position and derive the angle from the positional relationship between the two.

The height of the convex portion 11 is preferably 1.5 times or more the maximum diameter of the convex portion 11 from the viewpoint of improving the cushioning properties, more preferably 2 times or more the maximum diameter of the convex portion 11 from the viewpoint of further improving the cushioning properties, and even more preferably 3 times or more the maximum diameter of the convex portion 11 from the viewpoint of further improving the cushioning properties.
In addition, the height of the convex portion 11 is preferably 10 times or less the maximum diameter of the convex portion 11 from the viewpoint of stabilizing the shape after shaping, more preferably 9 times or less the maximum diameter of the convex portion 11 from the viewpoint of further stabilizing the shape after shaping, and even more preferably 8 times or less the maximum diameter of the convex portion 11 from the viewpoint of further stabilizing the shape after shaping.
The "maximum diameter" of the protrusions 11 refers to the maximum length of the protrusions 11 in the axial direction X1 and circumferential direction Y1 of the surface 10S of the support roll 10.

The top of the protrusion 11 is preferably roughened. This increases the ability to hook the fibers, favorably increasing the amount of fibers remaining at the top, and suppresses partial thinning of the fibers when pressed into the fiber material. In addition, roughening can produce a nonwoven fabric with less unevenness. The roughening may be performed only on a part of the top, may be performed only on the entire top, or may be performed from the top to a part of the upper part of the wall surface. In consideration of the ability to hook the fibers and the ease of the fibers to fit the wall surface, it is preferable that the entire top is roughened, and it is more preferable that the edge of the top is roughened. In consideration of the ease of peeling after nonwoven fabric is produced, it is preferable that only the top is roughened and the wall surface is not roughened.
The top surface can be roughened by various methods that are applied to this type of support roll 10, such as sandblasting.

Further, although not shown, it is preferable that the edge of the top of the convex portion 11 (the corner of the connecting portion between the top and the wall surface) be rounded. The roundness makes it easier to insert a push-in portion 22, which will be described later, between the convex portions 11, 11 (recessed portion 12).

The push-in net 21 has a width direction X2 parallel to the axial direction X1 of the support roll 10 and a longitudinal direction Y2 perpendicular to the width direction X2. The push-in net 21 has a loosely inserted portion 23 into which the above-described convex portion 11 is loosely inserted, and a push-in portion 22 into which the above-described concave portion 12 is loosely inserted, alternately along the width direction X2 and the longitudinal direction Y2. It is arranged in As a result, the push-in portions 22 are arranged in a grid pattern and surround the space of the loosely inserted portion 23. The lattice-shaped push-in portion 22 includes a push-in portion 221 extending in the longitudinal direction Y2 and a push-in portion 222 extending in the width direction X2.
"Loosely inserted" means inserted with some play. The convex portion 11 of the support roll 10 is inserted into the loosely inserted portion 23 of the push-in net 21, leaving a gap. The push-in portion 22 of the push-in net 21 is inserted into the recess 12 of the support roll 10 while leaving a gap. A fiber material is interposed in this gap.

As described above, in the push-in net 21, the portions surrounded by the lattice-shaped push-in portions 22 become the loosely inserted portions 23. The loosely inserted portions 23 are arranged in a grid pattern. The lattice-shaped push-in portions 22 are arranged in the axial direction X2 and longitudinal direction Y2 of the push-in net 21 so as to be loosely inserted into the lattice-shaped recesses 12 arranged in the axial direction X1 and circumferential direction Y1 of the support roll 10. Each loosely inserted portion 23 is arranged so that the protrusions 11 of the support roll 10 are loosely inserted into it.

In this embodiment, the uneven surface of the support roll 10 and the push-in net 21 are loosely inserted along the longitudinal direction Y2 of the push-in net 21 in accordance with the rotation of the support roll 10. Thereby, as shown in FIG. 4, the plurality of push-in nets 21 are loosely inserted in the circumferential direction Y1 of the uneven surface of the support roll 10 along the longitudinal direction Y2 while being lined up in the width direction X2. During loose insertion, a fiber material is interposed between the uneven surface of the support roll 10 and the push-in net 21. In addition, in FIG. 4, the push-in part 22 which comprises the push-in net 21 is shown by the thick line, and is simplified.
In the push-in net 21, the push-in portions 22 and loosely inserted portions 23 may be arranged to correspond to all of the recesses 12 and convex portions 11 in the circumferential direction Y1 of the support roll 10, or may be arranged to correspond to only some of them. may be arranged. For example, the pushing part 22 of the pushing net 21 may not be arranged in a part of the recessed part 12 in the circumferential direction Y1 of the support roll 10.

The push-in net 21 is divided into a plurality of parts in the width direction X2. Thereby, the push-in net 21 has movability whose position in the width direction X2 can be controlled. This movability occurs because the push-in nets 21, 21 adjacent to each other in the width direction X2 have portions that are not connected to each other. That is, this occurs because the mutual push-in nets 21, 21 do not restrict their movements in the width direction X2. Each of the push-in nets 21 can be moved independently of each other in accordance with the arrangement of the concave and convex portions of the support roll 10.
For example, in FIGS. 1 and 4, the push-in net 21 is divided into four parts in the width direction X2, so the four push-in nets 21 can be moved individually in the width direction X2. As a result, with respect to the entire length of the support roll 10 in the axial direction X1, which has undergone movement or thermal expansion, the push-in net 21 is subdivided into four parts, and the position in the width direction X2 can be controlled to a higher degree. Specifically, even if the thermal expansion of the support roll 10 occurs non-uniformly in the axial direction X1, the position can be controlled by the movability of each push-in net 21 in the width direction Become.
Moreover, it is preferable that the entire width of the plurality of push-in nets 21 divided in the width direction X2 corresponds to the entire length of the uneven surface of the support roll 10 in the axial direction X1. That is, it is preferable that the fibrous material be pushed by the pushing net 21 up to the end of the uneven surface of the support roll 10 in the axial direction X1.

The positional relationship between the convex portion 11 and the concave portion 12 of the support roll 10 and the pushing portion 22 of the pushing net 21 is shown, for example, in FIG. 5. The pushing portion 22 of width W is loosely inserted into the width D0 between the convex portions 11, 11 (concave portions 12) of the support roll 10. At this time, the distance D1 between one side of the pushing portion 22 and the side of the convex portion 11 and the distance D2 between the other side of the pushing portion 22 and the side of the convex portion 11 are clearances. These distances D0, width W and tolerance allowances D1 and D2 are all dimensions in millimeters. For example, if the width D0 between the convex portions 11, 11 is 4 mm and the width W of the pushing portion 22 is 2 mm, the clearance is 1 mm on one side. It is necessary to loosely insert the pushing portion 22 within this slight margin of 1 mm. It is preferable to control the position of the pushing portion 22 evenly over the entire width (for example, 2 to 4 m) of the support roll 10 and the pushing net 21.
In contrast, the nonwoven fabric manufacturing apparatus of this embodiment can execute the above-mentioned position control for each pressing net 21 during the formation of unevenness. In particular, the longer the support roll 10 is in the axial direction X1, the greater the effect of position control of the convex portion 11 and the pressing portion 22. For example, this embodiment enables position control in which the convex portion 11 and the pressing portion 22 are loosely inserted with a clearance of about 1 mm over a member width of 2 to 4 m (2000 mm to 4000 mm).

The push-in net 21 has high deformability at the intersection of the push-in portions 22, 22. Therefore, the push-in net 21 has flexibility in the width direction X2 and the longitudinal direction Y2 in addition to being movable in the width direction X2. This flexibility and the above-mentioned movability in the width direction X2 combine to allow the position control of the push-in net 21 to be performed instantaneously and in a timely manner during operation of the manufacturing apparatus 1. Furthermore, the flexibility of the push-in net 21 prevents sudden displacement of the uneven surface due to partial thermal expansion of the support roll 10 when the manufacturing apparatus 1 is stopped, so that the upstream machine direction (MD) The push-in net 21 (area R in FIG. 4) is pulled by the meshing portion (area Q in FIG. 4).
In addition, as shown in FIG. 4, even if a positional shift occurs on the uneven surface of the support roll 10 due to thermal expansion, etc., the pushing part 22 (area Q in FIG. 4) that engages with the uneven surface due to the above-mentioned position control will be pulled. The position of the push-in net 21 (region R in FIG. 4) connected upstream in the MD direction is corrected.

Various materials can be used for the wire that constitutes the push-in portion 22. For example, it may be a single fiber made of resin. Further, it is preferably a heat-resistant material, and more preferably one having heat resistance of 180° C. or higher. Specifically, it is preferably made of one or more materials selected from glass fiber, aramid fiber, polyphenylene sulfide, fluororesin, carbon fiber, and the like. A specific example of a material made of glass fiber is FGF-410-30 (trade name, manufactured by Chukoh Kasei Kogyo Co., Ltd.).
Regardless of the material, it is preferable to apply a resin coating or the like to the surface of the wire so that the fiber material to be processed does not get tangled, so that the wire material does not unravel or become fluffy. It is also possible to use metal such as stainless steel as the material.
Regardless of which material is used, the wire does not need to be composed of a single wire, and may be made of thin wires bundled to a desired thickness.

The push-in net 21 can be loosely inserted into the support roll 10 due to the mobility achieved by dividing the push-in net 21 into individual push-in nets 21 and the flexibility of the net itself. In particular, by separating the push-in nets 21, 21, loose insertion can be performed more accurately.

In the nonwoven fabric manufacturing apparatus 1 of this embodiment, as described above, even if the uneven surface of the support roll 10 moves or thermal expansion occurs, the position of the push-in net 21 in the width direction X2 and the longitudinal direction Y2 is corrected accordingly. controlled. As a result, the position of the loosely inserted portion 23 with respect to the convex portion 11 is corrected, and the loose insertion of the convex portion 11 into the loosely inserted portion 23 can be suitably performed. At the same time, the position of the push-in part 22 with respect to the recess 12 is corrected, and the push-in part 22 can be smoothly inserted into the recess 12. As a result, it is possible to satisfactorily form unevenness on the fiber material. Moreover, unexpected damage (holes and cuts) to the fiber material can be prevented. That is, it is possible to efficiently produce a high-quality nonwoven fabric with uneven shapes.

The method for producing a nonwoven fabric according to the present embodiment is carried out using the above-described nonwoven fabric production apparatus 1. More specifically, the method can be carried out as follows.
First, while rotating the support roll 10 in the MD direction, a fiber material is supplied between the support roll 10 and a plurality of push-in nets 21 arranged in the axial direction X1. The above-mentioned loose insertion is performed between the support roll 10 and the push-in net 21 to perform uneven shaping of the fiber material. The loose insertion is performed along the longitudinal direction Y2 in the entire push-in nets 21 arranged in the width direction X2, and uneven shaping of the fiber material is continuously performed. At that time, when there is contact between the convex portion 11 and the push-in portion 22, the position of the push-in net 21 in the width direction X2 and the longitudinal direction Y2 is corrected. As a result, the above-mentioned loose insertion can be suitably performed without stopping the operation of the manufacturing apparatus 1 during uneven shaping processing, and uneven shaping of the fiber material can be performed continuously and satisfactorily. As a result, it is possible to continuously produce high-quality unevenly shaped nonwoven fabrics with good yield and efficiency.
At this time, the pressing net 21 is pulled by the rotation of the support roll 10 at the meshing portion with the support roll 10, and moves in the MD direction at a predetermined speed. By driving the pressing net 21 in this manner, it is possible to synchronize the moving speeds of the multiple pressing nets 21 in the MD direction. This makes it possible to omit a mechanism for driving the pressing net 21.

The fiber material used in the manufacturing method of the nonwoven fabric of this embodiment can be any of various materials that can be formed into unevenness, without any particular restrictions. Examples include the nonwoven fabric and fiber web described above. The nonwoven fabric referred to here is a sheet-like raw nonwoven fabric before the unevenness is formed. As the raw nonwoven fabric, any of various materials commonly used in the field of nonwoven fabrics can be used without any particular restrictions, and can be manufactured by various commonly used methods. The fiber web is a sheet-like fiber assembly in which the fibers are not bonded at their intersections, and can be manufactured by various commonly used methods. For example, a carding method can be used. In the case of a fiber web, a step of bonding the fibers at their intersections is carried out after the unevenness is formed. In this bonding step, various commonly used methods can be used, such as chemical bonding, physical bonding, thermal bonding (fusion), mechanical bonding, etc. In the case of thermal bonding, it is preferable that the fiber web contains thermoplastic fibers.

In the nonwoven fabric manufacturing method of this embodiment, it is preferable to have a heating step in which the support roll 10 that imparts the unevenness to the fiber material is heated. That is, it is preferable that the nonwoven fabric manufacturing apparatus 1 has a heating device (not shown) that heats the support roll 10. By heating the support roll 10, the fiber material supported by the support roll 10 is also heated at the same time, and a nonwoven fabric with unevenness can be manufactured more efficiently. Note that the fiber material being supported by the support roll 10 broadly includes a state in which the fiber material is simply placed on the support roll 10, to a state in which the fiber material is imparted with unevenness and conforms to the uneven shape of the support roll 10.

When the support roll 10 is subjected to a heating process, specifically, the following process is carried out.
For example, when the fiber material is a fiber web, the fiber web is first placed on the support roll 10 and rotated while pressing the pressing net 21 against it, and the aforementioned loose insertion is performed to give the fiber web an uneven shape. The fiber web with the uneven shape is made to conform to the uneven shape of the support roll 10. Next, the fibers of the fiber web that are made to conform to the uneven shape of the support roll are fused together by the heating process while the uneven surface of the support roll 10 and the pressing net 21 are loosely inserted. As a result, the uneven shape of the fiber web is stably maintained by the support roll 10, and the uneven nonwoven fabric can be produced more efficiently.
For example, when the fiber material is a nonwoven fabric (raw nonwoven fabric), the nonwoven fabric is first placed on the support roll 10 and rotated while being heated just before shaping. This can reduce the fusion force between the fused fibers of the nonwoven fabric. After the fiber fusion force is weakened, the nonwoven fabric is placed on the support roll 10 and further rotated while being pressed against the pressing net 21, and the nonwoven fabric is shaped into unevenness by the above-mentioned loose insertion. This allows the nonwoven fabric (raw nonwoven fabric) to be heated and shaped into unevenness continuously on the support roll 10, making it possible to more efficiently manufacture unevenly shaped nonwoven fabric.

In either case, the heating step is preferably a step of blowing hot air toward the support roll 10 supporting the fiber material. That is, the heating device of the nonwoven fabric manufacturing apparatus 1 is preferably disposed in a position where hot air is blown toward the support roll 10 supporting the fiber material. By blowing hot air, the hot air penetrates the fiber material and heats it relatively evenly in the thickness direction. The temperature, wind speed, etc. of the hot air are all appropriately selected depending on the type of fiber, basis weight, etc. of the fiber material. In addition, it is preferable to use heated air as the hot air from the viewpoints of ease of handling and cost.

When such a heating step is performed, the support roll 10 is heated and thermally expanded, and the interval between the convex portions 11 arranged in the axial direction X1 may be extended. In this case, in the conventional shaping device, the pushing part 22 and the convex portions 11 come into strong contact with each other during uneven shaping, preventing loose insertion, and the production of the nonwoven fabric may stop.
However, in the nonwoven fabric manufacturing apparatus 1 and manufacturing method of the present embodiment, the pushing net 21 can move due to its flexibility and mobility so that the pushing part 22 and the protruding part 11 do not come into strong contact with each other. This allows the above-mentioned loose insertion to be performed favorably, and the uneven shaping of the fiber material can be performed favorably and continuously.
In particular, in a situation where operation must be temporarily stopped for some reason while the support roll 10 is being heated, the return to continuous production can be accelerated, which is more effective for efficient continuous production of unevenly shaped nonwoven fabrics. This is because the nonwoven fabric manufacturing apparatus and method of the present embodiment can solve the conventional problems in uneven shaping involving a heating step.
That is, when the uneven shaping is stopped, the heating device is difficult to temporarily stop due to its nature, and a part of the support roll 10 that has stopped rotating is exposed to hot air. In this case, there are parts in the support roll 10 with different degrees of thermal expansion, and the degree of positional deviation between the convex part 10 and the pushing part 22 also differs. In such a situation, in the conventional shaping device, the above-mentioned loose insertion between the support roll 10 and the pushing net 21 must be removed until the difference in the dimensions of the thermal expansion of the support roll 10 is within a certain range. In this case, it takes time to resume operation properly in the conventional case, resulting in production losses.
In contrast, the nonwoven fabric manufacturing apparatus 1 and the nonwoven fabric manufacturing method of the present embodiment can shorten the time until restarting operation by controlling the position of the pressing net 21 in response to the positional deviation. This can improve the continuous production efficiency of the nonwoven fabric having a concave-convex shape.

Furthermore, the nonwoven fabric manufacturing apparatus 1 of this embodiment may include a smooth roll (not shown) in contact with the outer peripheral surface of the support roll 10 on the downstream side of the push-in net 21. The smooth roll preferably includes a heating mechanism that heats the surface 10S of the support roll 10. As a result, while the unevenly shaped nonwoven fabric follows the uneven shape of the support roll 10, other fiber materials can be accurately heat-sealed and bonded using the smooth roll. That is, in heat fusion bonding using a smooth roll, the support roll 10 suitably holds the uneven shape of the nonwoven fabric, and a two-layer laminated nonwoven fabric having a good uneven shape can be manufactured. In addition, since the unevenly shaped nonwoven fabric is thermally bonded to other fiber materials at the portion supported by the convex portion 11 of the support roll 10, unnecessary thermal bonding is suppressed and the softness of the nonwoven fabric is improved. It can be made easier to maintain the quality.
In the above process, it is preferable to laminate other fiber materials on the nonwoven fabric after removing the push-in net 21 from the support roll 10. By removing the loose insertion in advance before lamination, it is possible to prevent the push-in net 21 from being buried inside the laminated nonwoven fabric.
Note that "downstream side" means a position behind a certain point in the MD direction of the manufacturing apparatus. Regarding the manufacturing method, it means the rear side of a certain process in the MD direction. Furthermore, a "smooth roll" means that there is no unevenness that would allow loose insertion between the protrusions 11 and the recesses 12 of the opposing support roll 10, and it enables uniform pressing against the protrusions 11. This means that the circumferential surface of the roll is relatively flat.

Next, preferred examples of the push-in net 21 (first to third embodiments) will be described with reference to Figures 6 to 8.

In the first embodiment, as shown in FIG. 6, a plurality of push-in nets 21 are arranged in the width direction X2 with an interval corresponding to one convex portion 11 of the support roll 10. By doing so, the above-described loose insertion can be performed without overlapping the push-in nets 21, 21 in the width direction X2.
In the first embodiment, since the pushing portion 22 does not exist between the pushing nets 21 and 21, the fibrous material is not pushed between the pushing nets 21 and 21. As a result, a ridge-like pattern can be created on the surface of the manufactured nonwoven fabric.

In the push-in net 21 of the second embodiment, as shown in FIG. 7, the push-in portion 222 extending in the width direction X2 protrudes from the end in the width direction X2 of the push-in portion 221 extending in the longitudinal direction Y2. By doing so, the interval between the pushing nets 21, 21 can be reduced, and it becomes easier to uniformly push the fiber material in the width direction X2. As a result, a nonwoven fabric with a more uniform surface can be produced.
In the second embodiment as well, similarly to the first embodiment, loose insertion can be performed without overlapping the push-in nets 21, 21 in the width direction X2. In addition, in the second embodiment, by appropriately changing the protruding length and structure of the pushing part 221, the pushing pattern of the fiber material between the pushing nets 21, 21 can be changed, and the nonwoven fabric having a unique pattern on the surface can be changed. can be manufactured.

In the third embodiment, as shown in Fig. 8A, a plurality of pushing nets 21 are arranged in the width direction X2 without any gaps between them, so that the fiber material can be pushed in over the entire width direction X2.
In the third embodiment, the ends of the push-in nets 21, 21 in the width direction X2 overlap each other, so that there is a portion where two push-in portions 22 are loosely inserted into one recess 12. Therefore, as shown in Fig. 8 (B), the push-in nets 21, 21 overlap each other in a staggered manner. As a result, it is possible to create a difference in height (thickness) in the uneven shape of the manufactured nonwoven fabric.

The unevenly shaped nonwoven fabric produced by the nonwoven fabric production apparatus and production method of the present invention can be applied to constituent members of various articles. Applicable articles include, for example, absorbent articles, cleaning supplies, filter materials, and the like.
An absorbent article typically has a top sheet, a back sheet, and an absorbent core sandwiched between the two sheets. The topsheet is typically liquid permeable. The backsheet is typically impermeable to liquids, but may be permeable to liquids. Absorbents serve to immobilize liquids and typically include pulp and superabsorbent polymers.
When the above-mentioned nonwoven fabric is used for an absorbent article, it is preferably applied to a topsheet. It is preferable to arrange it as a topsheet because it feels good to the touch. Note that absorbent articles include various types of articles that have the function of absorbing bodily fluids when worn on the body, such as diapers, sanitary napkins, urine absorbing pads, and panty liners.

REFERENCE SIGNS LIST 1 Manufacturing device 10 Support roll 10S Surface of support roll 11 Convex portion 12 Concave portion 21 Pressing net 22 Pressing portion 221 Pressing portion extending in the longitudinal direction 222 Pressing portion extending in the width direction 23 Loosely inserted portion

Claims (10)

A method for producing a nonwoven fabric, comprising: supplying a fiber web or a raw nonwoven fabric as a fiber material between a support roll and a pressing net to form a concave-convex shape;
The support roll has an uneven surface on its surface in which convex portions and concave portions are alternately arranged along the axial direction of the support roll,
The pressing net has a width direction parallel to the axial direction and a longitudinal direction perpendicular to the width direction,
The push-in net has a loose insertion portion into which the convex portion is loosely inserted and a push-in portion into which the concave portion is loosely inserted, which are alternately arranged along the width direction and the longitudinal direction,
The pressing net is divided into a plurality of parts in the width direction,
The uneven surface and the pressing net are loosely inserted in accordance with the rotation of the support roll,
A method for manufacturing a nonwoven fabric, wherein the fiber material is interposed between the uneven surface and the pressing net during the loose insertion. The method for manufacturing a nonwoven fabric according to claim 1, comprising a heating step in which the support roll is heated. the fibrous material is a fibrous web,
The method for producing a nonwoven fabric according to claim 2 , wherein after the fiber web is formed into an uneven shape by the insertion, the fibers of the fiber web that have been aligned to the uneven shape of the support roll are fused together by the heating step. The method for manufacturing a nonwoven fabric according to claim 3, in which the fibers of the fiber web are fused together while the uneven surface of the support roll and the pressing net are loosely inserted. The fiber material is the raw nonwoven fabric,
3. The method for producing a nonwoven fabric according to claim 2, wherein the heating step weakens the fiber fusion strength of the raw nonwoven fabric placed on the support roll, and then the insertion is performed to give the raw nonwoven fabric an uneven shape. The method for producing a nonwoven fabric according to any one of claims 2 to 5, wherein the heating step is a step of blowing hot air toward the support roll supporting the fiber material. A nonwoven fabric manufacturing device that supplies a fibrous web or a raw nonwoven fabric as a fibrous material between a support roll and a push-in net to form unevenness,
The support roll has an uneven surface on its surface in which convex portions and concave portions are alternately arranged along the axial direction of the support roll,
The push-in net has a width direction parallel to the axial direction and a longitudinal direction perpendicular to the width direction,
In the push-in net, a loosely inserted part into which the convex part is loosely inserted and a pushing part into which the concave part is loosely inserted are arranged alternately along the width direction and the longitudinal direction,
The push-in net is divided into a plurality of parts in the width direction ,
A nonwoven fabric manufacturing apparatus , wherein the uneven surface and the push-in net are loosely inserted in accordance with the rotation of the support roll . The nonwoven fabric manufacturing apparatus according to claim 7, further comprising a heating device that heats the support roll. 9. The nonwoven fabric manufacturing apparatus according to claim 8, wherein the heating device blows hot air toward the support roll supporting the fiber material. The nonwoven fabric manufacturing apparatus according to any one of claims 7 to 9, further comprising a smooth roll downstream of the pressing net that contacts the outer peripheral surface of the support roll, the smooth roll being equipped with a heating mechanism.

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