TWI671063B - Non-woven fabric for absorbent articles - Google Patents

Abstract

An object of the present invention is to obtain a nonwoven fabric for an absorbent article that can obtain a soft touch when contacting the skin and can securely secure the soft touch.

That is, the non-woven fabric for an absorbent article of the present invention is composed of a groove bottom (6) at a groove portion (5) of a groove portion (5) provided in a space between adjacent convex portions (4), (4), and The bottom portion (9) is deeper than the bottom portion (6) of the groove and is provided with a plurality of recesses (7) discontinuously arranged in the first direction (X). At least a part of the peripheral surface of the recess (7) is provided with The hole portion (11) leading to the second surface (3) side has a peripheral edge portion (12) which can be formed without melting thermoplastic resin fibers, and a bottom portion (9) of the recessed portion (7). The fiber has a higher fiber density than the convex portion (4) and is formed into a planar shape at least on the second surface (3) side.

Description

Non-woven fabrics for absorbent articles

The present invention relates to nonwoven fabrics for absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads.

For example, in absorbent articles such as disposable diapers, non-woven fabrics used as constituent members such as top sheets are in contact with the skin of the user, so softness and good touch become important conditions.

Therefore, in recent years, non-woven fabrics having a plurality of rows of rib-shaped convex portions and groove portions provided in spaces between adjacent convex portions have been used in many cases. The relatively soft convex portions contact the skin, and the convex portions are easily adhered to the skin surface. Therefore, the softness of the non-woven fabric tends to be easily felt.

In such a nonwoven fabric, there is a structure in which, as described in Patent Document 1, a through-hole that penetrates the thickness direction of the nonwoven fabric is provided in a groove portion between convex portions, as described in Patent Document 1, for example. The non-woven fabric described in this Patent Document 1 has a degree of freedom in the movement of the convex portion or a degree of freedom in the movement of the fiber through the through hole. By following the action of the skin, it becomes easier to feel the softness of the convex portion, and therefore it is easier to feel the touch.

However, in the nonwoven fabric described in Patent Document 1, in the step of forming the through-hole in the groove portion, the thermoplastic resin fibers in the nonwoven fabric are melted while the pins provided on the pin rollers for forming the through-holes are melted. The through-holes are formed by penetrating the thickness direction of the nonwoven fabric. Therefore, the peripheral edges of the through-holes are easily hardened by melting.

Therefore, when the skin touches the non-woven fabric, especially when the non-woven fabric is pressed in the thickness direction, or when the skin is slid in the plane direction of the non-woven fabric, the skin may feel obvious non-uniformity when it contacts the hard part of the periphery of the through hole. Comfort, which is thought to severely impair the feel of nonwovens.

On the other hand, when the non-woven fabric cited in Reference 1 is used as the top sheet of an absorbent article, the surface of the non-woven fabric opposite to the protruding side of the convex portion abuts the absorbent body of the absorbent article. The opening edge of the through hole of the non-woven fabric of Document 1 is projected toward a surface opposite to the protruding side of the convex portion. Therefore, the opening edge of the through hole is in contact with the absorber.

However, the opening edge of the through-hole is very thin, and is substantially in a linear contact state with the absorber. Therefore, it is very fragile. With only a little force, the opening edge of the through-hole or the entire through-hole may be damaged.

Therefore, it is presumed that the nonwoven fabric as the top sheet is pressed against the absorbent body by the skin of the user, or the entire absorbent body is compressed when the absorbent article as a product is folded and stored in a packaging bag for transportation. , Excessive compressive force will act on the opening edge of the through hole, destroying the through Holes or opening edges that cannot restore the original shape of the nonwoven. Therefore, the non-woven fabric cited in Reference 1 is used in an absorbent article, and the softness inherent in the non-woven fabric may not be exhibited, and a desired feeling of use may not be obtained.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 8-302555

A technical object of the present invention is to provide a nonwoven fabric for an absorbent article that can obtain a soft touch when contacting the skin and can securely secure the soft touch.

In order to solve the aforementioned problems, the structure of the nonwoven fabric for absorbent articles of the present invention is as follows.

(1) A non-woven fabric for an absorbent article, which has a first surface and a second surface opposite to the first surface, and includes a convex portion protruding toward the first surface side and a recessed portion toward the second surface side. A groove portion, and the non-woven fabric contains thermoplastic resin fibers, wherein the convex portion is extended toward the first direction of the surface of the non-woven fabric, and the second surface of the non-woven fabric is orthogonal to the first direction in the second direction; Pluralities are provided at predetermined intervals in the direction The row, the groove portion is provided in a space extending between the convex portions adjacent in the second direction toward the first direction, and at the bottom of the groove of the groove portion, the groove portion The bottom of the groove is closer to the bottom of the second surface, and includes a plurality of recesses that are discontinuously provided in the first direction. At least a part of the peripheral surface of the recess is provided with a hole that leads to the second surface. The hole portion has a peripheral edge portion that can be formed without melting the thermoplastic resin fibers, and the bottom portion of the concave portion has a higher fiber density than the convex portion and at least the second surface side is formed into a planar shape.

(2) The nonwoven fabric for absorbent articles according to the above (1), wherein the recessed portion has a first peripheral surface formed as a pair along the first direction, and along the second The pair of second peripheral surfaces are formed in a directional manner, the hole portion is provided only on the first peripheral surface, and the second peripheral surface is continuous with the groove bottom of the groove portion.

(3) The non-woven fabric for absorbent articles according to (1) or (2), wherein the thickness of the bottom portion of the recessed portion is greater than the thickness of a portion of the convex portion that protrudes most toward the first surface side. smaller.

(4) The nonwoven fabric for absorbent articles according to any one of (1) to (3), wherein the fiber density of the bottom portion of the recessed portion is 1.3 to 1.5 times the fiber density of the convex portion.

(5) The non-woven fabric for absorbent articles according to any one of (1) to (4), wherein a height from a height of a first surface side of a bottom of the groove to a bottom of the groove is The dimension of the height of the first surface side is 50 to 80% of the dimension from the height of the first surface side of the groove bottom portion to the height of the top portion of the convex portion.

(6) The non-woven fabric for absorbent articles according to any one of (1) to (5), wherein the interval between the convex portion and other adjacent convex portions is 0.25 to 5 mm.

According to the present invention, since the concave portion provided in the groove bottom of the groove portion provided between the convex portions increases the freedom of movement of the convex portion or the fiber of the convex portion, and the convex portion is made by the hole portion of the concave portion. As the tensile force is reduced, the entire convex portion becomes soft, so the softness when contacting the skin is ensured.

On the other hand, in the case of an absorbent article, since the bottom of the recessed portion suppresses the deformation of the nonwoven fabric and stabilizes the ground to contact other members of the absorbent article, the entire nonwoven fabric is supported by the recessed portion, which is easy to maintain the shape and can be maintained stably Ensure a soft touch.

1‧‧‧ Non-woven fabric for absorbent articles

2‧‧‧ non-woven upper surface (first side)

3‧‧‧ lower surface of non-woven fabric (second side)

4‧‧‧ convex

4a‧‧‧Top

5‧‧‧Groove section

6‧‧‧ bottom of the trench

7‧‧‧ recess

8‧‧‧ weekly

8a‧‧‧First week

8b‧‧‧ 2nd week

9‧‧‧ bottom

11‧‧‧ Hole

11a‧‧‧ Internal space of the hole

12‧‧‧periphery

13‧‧‧ broken fiber

13a‧‧‧ fracture end

14‧‧‧ fiber

50‧‧‧ manufacturing equipment

51‧‧‧Non-woven

52‧‧‧Unwinding device

61‧‧‧preheating device

61a, 61b‧‧‧heating roller

62‧‧‧Shaping device

63, 64‧‧‧ extension roller

63a‧‧‧ ridge

63b‧‧‧concave groove

64a‧‧‧pin

MD‧‧‧ Transport direction

[Fig. 1] Fig. 1 is a plan view schematically showing an embodiment of a nonwoven fabric for an absorbent article of the present invention.

[Fig. 2] Fig. 2 is a partially cutaway perspective view schematically showing an embodiment of the nonwoven fabric for absorbent articles of the present invention.

[Fig. 3] Fig. 3 is an enlarged sectional view of an important part of Fig. 1.

[FIG. 4] FIG. 4 is a photograph showing a periphery of a hole portion of a recessed portion of the nonwoven fabric for an absorbent article of the present invention.

[Fig. 5] Fig. 5 schematically shows the absorption used to make the present invention An example of an apparatus for manufacturing a nonwoven fabric for sexual articles.

[Fig. 6] Fig. 6 is an enlarged perspective view schematically showing important portions of a pair of extension rollers of the shaping device.

[Fig. 7] Fig. 7 is an enlarged view schematically showing an important part of the arrangement of the pins of the lower extension roller.

[Fig. 8] Fig. 8 is an enlarged view of an important part showing an engagement state between the upper extension roller and the lower extension roller.

Figures 1 to 4 show one embodiment of the non-woven fabric for absorbent articles of the present invention. The non-woven fabric 1 of this embodiment has the first surface, that is, the upper surface, in Figures 1 to 4 2. The second surface opposite to the upper surface 2, that is, the lower surface 3, is provided with a convex portion 4 protruding toward the upper surface 2 side, and a groove portion 5 recessed toward the lower surface 3 side. The non-woven fabric is For users of absorbent articles containing thermoplastic resin fibers.

In addition, the non-woven fabric of the present invention is a top sheet or a leak-proof wall suitable for use as an absorbent article such as disposable paper diapers or sanitary napkins, urine pads, sanitary pads, etc. The sheet on the side of the article that is in contact with the user's skin. Alternatively, a sheet to be attached to the outer side surface of a back sheet such as a disposable diaper can be used.

The non-woven fabric 1 is a generally corrugated sheet formed by alternately folding the non-woven fabric before processing as a material toward the upper surface side and the lower surface side. In this embodiment, the non-woven fabric 1 is configured to face the upper surface side. The folded portion forms a convex portion 4 which has been bent upward in the conventional manner. The folded portion on the front side forms a groove portion 5 which has been bent downward in the conventional manner.

The convex portion 4 is continuously extended toward the first direction X of the surface (sheet surface) of the non-woven fabric 1, and the non-woven fabric 1 is provided at a predetermined interval in the second direction Y orthogonal to the first direction X. With plural columns. In this embodiment, each of the convex portions 4 is continuously extended toward the first direction X and substantially parallel to the other convex portions 4.

On the other hand, the groove portion 5 is provided in a space extending between the adjacent convex portions 4 and 4 in the second direction Y toward the first direction X. The groove portion 5 is recessed toward the lower side than the top portion 4 a of the convex portion 4. Groove bottom 6.

Regarding the convex portion, the interval between the convex portion and other adjacent convex portions is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and still more preferably 0.75 to 2 mm. Here, the interval between the adjacent convex portions means the distance between the substantially central positions (substantially the apex portions) of the convex portions in the second direction.

If the distance between adjacent convex parts is less than 0.25mm, it is difficult to say that the non-woven fabric will have an uneven structure. Since the contact area between the convex parts and the skin cannot be greatly reduced, the touch may be reduced. On the other hand, Conversely, if it exceeds 5 mm, it will not be much different from the non-woven fabric of the object to be processed before processing. Therefore, a soft touch using unevenness cannot be obtained.

The height of the convex portion is from the deepest position (the second surface side of the non-woven fabric) at the bottom of the groove to the highest position of the convex portion (usually the top of the convex portion). 0.25 ~ 5mm, more preferably 0.5 ~ 3mm, and more preferably 0.75 ~ 2mm. If the height is less than 0.25 mm, the protrusion of the convex portion is too small, and the structure using the uneven structure cannot be obtained. Soft touch. On the other hand, if it exceeds 5 mm, the convex part will protrude too much and become a sharp structure. Therefore, a soft touch cannot be obtained.

The bottom portion 6 of the groove portion 5 is provided with a bottom portion 9 located on the lower surface 3 side than the groove bottom portion 6 of the groove portion 5 and is provided with a plurality of discontinuous settings in the first direction X.个 槽 部 7。 The recessed portion 7.

The recessed portions 7 are each provided with a standing wall-shaped peripheral surface 8 extending toward the lower surface 3 side in a state continuous with the groove bottom portion 6, and the bottom portion 9 provided on the lower end side of the peripheral surface 8.

In this embodiment, the recessed portions 7 have a substantially rectangular opening peripheral surface 8 and a bottom portion 9 in plan view, and have a substantially rectangular parallelepiped-like space having an upper opening. Each of the recessed portions 7 is connected to the bottom of the nonwoven fabric 1. The surface 3 side protrudes and is formed in a state independent of the other recesses 7.

The peripheral surface 8 is provided with a pair of first peripheral surfaces 8a, 8a extending in a pair so as to extend along the first direction X, and a pair of second peripheral surfaces extending in a pair so as to extend along the second direction Y. 8b, 8b, a pair of first peripheral surfaces 8a, 8a are disposed at positions facing each other, and a pair of second peripheral surfaces 8b, 8b are also disposed at positions facing each other.

Further, as shown in FIGS. 2 to 4, the recessed portion 7 is formed on the first peripheral surface 8 a of the peripheral surface 8 with a hole penetrating through the first peripheral surface 8 a to the lower surface 3 side of the nonwoven fabric 1. The second peripheral surface 8b, 8b and the groove bottom portion 6 of the groove portion 5 are continuously and seamlessly connected.

As shown in FIG. 2, in this embodiment, one hole portion 11 is provided on each of the pair of first peripheral surfaces 8a and 8a, and the hole portions 11 are formed near Of the bottom portion 9 of the recessed portion 7 of the first peripheral surface 8a Position (therefore, there are two holes 11 in one recess 7).

On the other hand, there is no pair of second peripheral surfaces 8b, 8b corresponding to the hole portion 11, and each second peripheral surface 8b is in a state where all of the lower end side and the bottom portion 9 are directly connected without interruption.

Here, the reason for providing the recessed portion is to minimize the chance of the bottom of the groove of the groove portion contacting the skin or the contact area when contacting the skin. That is, the non-woven fabric of the present invention is easy to contact the skin in the order of the groove bottom of the convex portion and the groove portion. Since the convex portion has the highest flexibility, the convex portion has a greater chance of contacting the skin than the bottom of the groove. The smaller the area of contact with the skin as a non-woven fabric, the easier it is to feel softness. Therefore, by providing the recessed portion, the portion of the groove bottom portion that contacts the skin is further reduced, and the chance of contacting the skin and the contact area are reduced as much as possible.

In addition, the reason for providing the recessed portion at the bottom of the groove is to form a portion that does not easily touch the skin, and to secure the rigidity of the bottom portion, which will be described later, in the portion that does not easily touch the skin, to fill the non-woven fabric. Strength when compressed.

The size of the recessed portion is from the height of the first surface (in this case, the upper surface) side to the bottom of the groove portion to the height of the first surface side of the bottom portion of the recessed portion, and is preferably set to 0.05 to 2 mm. , More preferably set to 0.075 ~ 1.5mm, and even better set to 0.1 ~ 1mm.

If the dimension from the height of the first surface side of the bottom of the groove to the height of the first surface side of the bottom of the recess is less than 0.05 mm, it will be difficult to ensure the rigidity of the bottom, which will be described later, and the strength in the thickness direction of the non-woven fabric. Will be insufficient, on the contrary, if it exceeds 2mm, it should be used with other components of the absorbent article, such as When the absorbent body, non-woven fabric, film, or the like is bonded, strength in the thickness direction is not generated, and rigidity may be felt during compression.

In addition, regarding the relationship between the concave portion and the convex portion, the dimension from the height of the first surface side of the bottom of the groove to the height of the first surface side of the bottom of the groove is preferably set from the groove of the groove The height from the first surface side of the bottom of the groove to the height of the top of the convex portion is 10 to 80%, more preferably 15 to 70%, and still more preferably 20 to 60%.

If the dimension from the height of the first surface side of the bottom of the groove to the height of the first surface side of the bottom of the recess does not reach the height of the first surface of the bottom of the groove to the top of the convex portion If the height is 10%, the space for forming the holes on the peripheral surface cannot be sufficiently ensured, and the formation of the holes may be insufficient, and the flexibility as a convex portion or even a non-woven fabric cannot be obtained. On the contrary, if it exceeds 80%, the recessed portion will be too deep, the strength of the peripheral surface of the recessed portion will be reduced, and fluffing will occur easily. Therefore, there is a possibility that the feel will be reduced.

In addition, although the length of the concave portion in the first direction depends on the groove width of the groove portion, that is, the distance between adjacent convex portions, it is preferably set to 0.25 to 5 mm, and more preferably set to 0.5 to 3mm, and more preferably 0.75 ~ 2mm.

If the length of the recess in the first direction is less than 0.25mm, the recess will become too small, and the recess may have almost no function. On the contrary, if it exceeds 5mm, the recess will become too long in the first direction, and it is flat. Non-woven fabrics or non-woven fabrics without recesses do not have much difference in softness, and a soft touch cannot be obtained.

On the other hand, the length in the second direction of the recessed portion depends on the groove portion. The groove width is wide, but it is preferably set to 0.25 to 5 mm, more preferably set to 0.5 to 3 mm, and even more preferably set to 0.75 to 2 mm.

If the length in the second direction of the recessed portion is less than 0.25 mm, the recessed portion will still become too small, especially the formation of the bottom portion will be insufficient. Therefore, the recessed portion may have almost no function. On the contrary, if it exceeds 5 mm, the recessed portion It may become too large, and the nonwoven fabric may be hardened due to a relationship with the rigidity of the bottom portion described later.

Furthermore, regarding the size of the hole portion, the length of the largest portion of the hole portion (the length in the first direction X in this embodiment) depends on the size of the recess portion, but is preferably the same as the size of the formed peripheral surface. For a small range, set it to 0.25 to 5 mm, more preferably set to 0.5 to 3 mm, and even more preferably set to 0.75 to 2 mm.

If the length of the largest portion of the hole portion is less than 0.25 mm, the formation of the hole portion will be insufficient, and the flexibility of the concave portion cannot be ensured, and the tensile force of the fibers of the convex portion will not be reduced, and sufficient flexibility of the convex portion cannot be ensured. Sex. On the contrary, if it exceeds 5 mm, the hole portion will be too large, and the peripheral edge portion will be prone to pilling, which may cause discomfort or foreign body feeling in the hole portion, and there is a possibility that the touch of the non-woven fabric may be reduced.

In addition, although the length in the height direction of the hole portion depends on the depth of the concave portion, it is preferably set to 0.1 to 5 mm, more preferably 0.25 to 3 mm, and even more preferably 0.5 to 2 mm.

If the maximum length in the height direction of the hole portion is less than 0.1 mm, the formation of the hole portion will be insufficient. In this case, the flexibility of the concave portion cannot be ensured, and the tensile force of the fibers of the convex portion will not be reduced. Ensuring sufficient protrusions Softness. Conversely, if it exceeds 5 mm, the peripheral edge portion of the hole portion becomes too large, and the peripheral edge portion is liable to pilling, and the uncomfortable feeling or foreign body feeling of the hole portion is likely to occur. Therefore, the touch of the non-woven fabric may be reduced.

On the other hand, the reason that the hole portion is provided only on the first peripheral surface and the second peripheral surface is continuous with the groove bottom of the groove portion is because the fibers of the convex portion adjacent to the groove portion provided with the hole portion The tensile force is released to improve the freedom of movement of the entire convex portion or the fibers forming the convex portion. On the other hand, when the skin slides in the first direction, it is difficult to feel the existence of the concave portion or the hole portion of the concave portion.

That is, the degree of freedom of the convex portion or the fiber of the convex portion is increased by forming the hole portion only on the first peripheral surface, thereby improving the softness of the convex portion, and more specifically, the thickness of the nonwoven fabric for the convex portion. The softness of the direction and the softness when the skin slides in the plane direction of the non-woven fabric, especially the second direction, ensure a smooth feel.

In addition, the second peripheral surface is continuous with the bottom of the groove portion. When the skin slides in the first direction, that is, the direction in which the convex portion or the groove portion extends, the hole portion is not easy to hook to the skin. It becomes more difficult to feel the presence of the hole portion, so it becomes difficult to feel uncomfortable or a foreign body feeling. In particular, when the skin slides in the first direction, it is different from the case where the skin slides in the second direction. The skin easily contacts the recessed portions, but even in this case, since it is difficult to feel the holes, it is not easy to damage mainly from the convex portions. The soft feel of the non-woven fabric obtained.

Thereby, both an excellent soft and hard feeling (excellent softness in the thickness direction of the nonwoven fabric) and an excellent rough feeling in the second direction of the nonwoven fabric (excellent smoothness in the planar direction of the nonwoven fabric) are imparted to the convex portion. , Becomes In order to ensure excellent soft and hard feel and rough feel of the entire non-woven fabric, soft touch can be realized.

Furthermore, the reason for providing the hole portion near the bottom of the recessed portion of the first peripheral surface is to minimize the number of holes by keeping the hole portion as far away as possible from the bottom portion of the convex portion or the groove portion that easily contacts the skin. The skin contact with the skin without feeling uncomfortable or foreign body.

Thereby, the smoothness of the skin when the non-woven fabric slides in a flat direction can be more stably ensured.

In addition, the hole portion 11 is provided with a peripheral edge portion 12. The peripheral edge portion 12 does not need to melt the thermoplastic resin fibers included in the nonwoven fabric 1, but is formed by breaking the thermoplastic resin fibers.

More specifically, as shown in FIGS. 3 and 4, the peripheral edge portion 12 of the hole portion 11 includes a broken end portion 13 a including broken fibers 13. The broken end portion 13 a is a thermoplastic resin fiber in the nonwoven fabric 1. It is formed by fracture. Therefore, the peripheral edge portion 12 of the hole portion 11 is formed without the thermoplastic resin fibers that are hardened by melting, and is formed by the broken fibers 13 having the broken end portion 13a. The broken end portion 13a is a soft thermoplastic resin. A part of the fiber or a thermoplastic resin fiber is formed by breaking. With this, even if the skin of the human body contacts the peripheral edge portion 12 of the hole portion 11, because there is no hardened thermoplastic resin fiber, it is possible to suppress the hardness or thickness of the nonwoven fabric as much as possible.

Here, the broken fiber 13 is a fiber forming a part of the thermoplastic resin fiber of the first peripheral surface 8a and is provided with a broken end portion 13a. The broken end portion 13a is formed by lengthening the thermoplastic resin fiber toward the length. It is formed by stretching or physically cutting in a direction to break it.

Therefore, the broken end portion 13a does not need to melt the end portion of the fiber into a circular shape to increase the fiber diameter, as in the case of melting thermoplastic resin fibers, but it becomes thinner by tearing or almost No change in fiber diameter. With this, even when the skin of the human body contacts the peripheral edge portion 12 of the hole portion 11, it is possible to suppress the uncomfortable feeling caused by the roughness or the hooking of the fiber.

Furthermore, as shown in FIG. 3 and FIG. 4, a part of the fibers 14 of the thermoplastic resin fibers spans the internal space 11 a of the hole portion 11. In addition, for a part of the broken fibers 13, the broken end portion 13 a is in a state of extending to the internal space 11 a of the hole portion 11.

Therefore, the internal space 11a of the hole portion 11 is in a state where the fibers 14 crossing the internal space 11a and a part of the extended fibers are mixed, instead of being a completely open space.

As described above, the structure of a part of the thermoplastic resin fiber that crosses the internal space of the hole is because the thermoplastic resin fiber that crosses the internal space as small as possible even when the skin contacts the hole. The difference between the perimeter or bottom and the pores makes it difficult to feel the discomfort caused by the objects in contact. That is, the thermoplastic resin fibers that cross the inner space of the hole can prevent the skin from completely passing through the hole to the second surface side (lower surface side) of the non-woven fabric. Therefore, the boundary between the peripheral surface or the bottom and the hole is different. The tactile sensation is reduced, whereby the tactile sensation becomes smoother, and it becomes difficult to feel uncomfortable at the contact hole portion.

In addition, even at a part of the broken fiber, the broken end portion extends to the hole In the case of the internal space of the part, the tactile sensation due to the difference between the peripheral surface of the recessed part or the step between the bottom part and the hole part is reduced, so the tactile sensation is still smooth.

At this time, the opening ratio of the internal space of the hole portion is preferably set to 1 to 50%, more preferably 1.5 to 35%, and even more preferably 2.5 to 20%.

If the opening ratio of the internal space of the hole portion is less than 1%, the opening ratio is too low to give the convex portion or the fiber freedom of the convex portion, and the flexibility of the convex portion cannot be sufficiently ensured. Conversely, if it is 50% or more, the strength of the peripheral surface provided with the hole portion (in this embodiment, the first peripheral surface 8a) tends to be low, and the boundary of the peripheral edge portion of the hole portion may be easily felt clearly. .

However, the opening ratio of the internal space of the hole portion can be arbitrarily set outside the aforementioned range depending on the type or application of the absorbent article using a non-woven fabric.

Next, the bottom portion 9 of the concave portion 7 has a higher fiber density than the convex portion 4 and the second surface 3 side is formed into a planar shape.

In this embodiment, the bottom portion 9 has a structure in which both the first surface 2 side and the second surface 3 side are formed into a substantially flat planar shape.

Here, the reason why the fiber density of the bottom portion 9 is higher than the fiber density of the convex portion 4 is that the non-woven fabric 1 is used in an absorbent article by making the bottom portion 9 harder than the convex portion 4 to suppress deformation as much as possible. In this case, the deformation of the non-woven fabric accompanying the deformation of the absorbent article is suppressed as much as possible, and the bottom portion 9 is stably pressed by other members, so as to maintain the shape of the entire non-woven fabric 1 as much as possible. With this, the non-woven fabric can be maintained 1's soft touch.

Specifically, when a non-woven fabric is used on a top sheet or a leak-proof wall of absorbent articles such as sanitary napkins or disposable diapers, or on the surface of a back sheet, the user's During the operation, the non-woven fabric will be bent, twisted, or pressed by the skin. In addition, when the absorbent article is stored in a package such as a bag for sale or transportation, the entire absorbent article is also bent and compressed, and the nonwoven fabric is easily deformed. However, in the present invention, since the fiber density at the bottom portion is made higher and harder than the fiber density at the convex portion, the bottom portion can suppress the deformation of the non-woven fabric as much as possible, and the original shape can be restored even if the deformation does not occur. High sex. Therefore, the shape of the nonwoven fabric can be stably maintained and the soft touch of the nonwoven fabric can be maintained.

In addition, when a nonwoven fabric is used as the top sheet, the absorbent absorbent body abuts against the second surface side of the bottom portion and presses the bottom portion toward the first surface side. Furthermore, after attaching the non-woven fabric to the surface after use, In the case of the outer surface of the back sheet of a disposable diaper, the back sheet abuts against the second surface side of the bottom portion and presses the bottom portion toward the first surface side. Therefore, this bottom portion is supported by the peripheral surface of the recessed portion The nonwoven fabric as a whole maintains the shape of the nonwoven fabric more stably.

Therefore, due to the rigidity of the bottom portion accompanying the high density of the fiber density at the bottom portion of the recessed portion, the shape of the nonwoven fabric is stably maintained, so that the soft touch of the protruding portion can be maintained.

The reason why the second surface 3 side of the bottom portion 9 is formed in a planar shape is that when the nonwoven fabric 1 is used in an absorbent article, The bottom 9 is in contact with other members of the absorbent article, and the bottom 9 is pressed more stably, which helps maintain the shape of the nonwoven fabric 1.

That is, in the case of linearly contacting other members of the absorbent article as before, the contacted parts are easily destroyed and the shape of the non-woven fabric cannot be maintained. However, when the surface contact is formed as in the present invention, the The pressing force is transmitted easily and stably, and the nonwoven fabric is pressed to the first surface side through the peripheral wall of the recessed portion. Therefore, even if the nonwoven fabric is crushed in the thickness direction, the shape of the nonwoven fabric can be restored and maintained.

This makes it possible to maintain the soft touch of the nonwoven fabric more stably.

In the present invention, although the fiber density at the bottom of the recessed portion depends on the absorbent article or application used (top sheet or leak-proof wall, attached to the outer surface of the back sheet, etc.), In a higher range, for example, it is preferably set to 0.005 to 0.3 g / cm ³ , more preferably set to 0.01 to 0.25 g / cm ³ , and still more preferably set to 0.015 to 0.2 g / cm ³ .

If the fiber density at the bottom portion is less than 0.005 g / cm ³ , the fiber density becomes too low, and the bottom portion becomes prone to fluff. Therefore, it is easy to feel uncomfortable or foreign body feeling at the bottom portion. On the contrary, if it exceeds 0.3 g / cm ³ , the fiber density becomes too high and the bottom becomes too stiff, so it is still easy to cause discomfort or foreign body feeling.

Furthermore, in the relationship between the bottom portion and the convex portion, the fiber density at the bottom portion is preferably 1.3 to 15 times the fiber density of the convex portion.

If the fiber density at the bottom is less than 1.3 times the fiber density at the convex portion, the difference between the fiber density at the bottom and the fiber density at the convex portion is too small. Therefore, the unevenness of the nonwoven fabric may not be sufficiently formed. strength Defective and unable to maintain the uneven shape of the nonwoven fabric. Conversely, if it exceeds 15 times, the difference between the fiber density at the bottom and the fiber density at the convex portion is too large. Therefore, excessive pressure may be applied to one of the concave portion or the bottom portion to cause excessive compression, and the other may have insufficient pressure to cause compression. Insufficient formation of the concave portion or the bottom portion results in difficulty in maintaining the uneven shape of the nonwoven fabric.

Here, the fiber density of the bottom part or the convex part can be measured by an arbitrary method.

As a method for measuring the fiber density, for example, the cut surface in the thickness direction of the non-woven fabric may be measured with an electron microscope (for example, a scanning electron microscope such as JCM-5100 manufactured by Japan Electronics Co., Ltd.), and the basis weight may be measured. Calculated by dividing by thickness.

Alternatively, the measurement can be performed by the following method. That is, the cut surface in the thickness direction of the non-woven fabric is magnified and observed using the aforementioned electron microscope (the magnification is adjusted so that the number of cross sections of the fiber that can be measured is 30 to 60 (for example, 150 to 500 times)). The number of faces and the area of the visual field where the number of fiber cross sections was measured, and the fiber density (root / mm ² ) were calculated. The measurement may be performed at several locations (for example, 3 to 5 locations), and the average value may be calculated.

In addition, in this embodiment, the thickness of the bottom portion 9 of the concave portion 7 is formed to be smaller than that of the portion protruding toward the first surface 2 side of the convex portion 4, that is, the thickness of the top portion 4a.

As such, the reason why the thickness of the bottom portion is smaller than that of the portion protruding toward the first surface side of the convex portion is that the fiber density of the bottom portion 9 is increased to guarantee the strength. On the other hand, the convex portion 4 is in contact with the skin. The part thus becomes soft without increasing the fiber density.

The thickness of the bottom is preferably about 3 to 60% of the thickness of the top of the convex portion, and more preferably about 5 to 50%. If the thickness of the bottom is less than 3% of the thickness of the top of the convex portion, the fiber density at the bottom becomes too high and becomes too stiff, which may damage the softness of the entire nonwoven fabric. Conversely, if it exceeds 60%, The fiber density becomes too low to make the bottom sufficiently formed, and the strength of the bottom cannot be ensured.

Hereinafter, the manufacturing method of the nonwoven fabric 1 for absorbent articles which has the said structure is demonstrated.

5 to 8 show an example of a manufacturing apparatus for manufacturing the nonwoven fabric 1. The manufacturing apparatus 50 includes an unwinding device 52, a preheating device 61, and a shaping device 62. The unwinding device 52. The non-woven fabric 51 to be processed to make the non-woven fabric 1 is rolled into a roll shape, and the non-woven fabric 51 to be processed is unwound toward the conveying direction MD. The preheating device 61 The unwinding device 52 unwinds the pre-heated non-woven fabric 51; the forming device 62 is configured to extend the non-woven fabric 51 that is pre-heated to the processed object to form a convex portion and a groove portion (including Recessed part).

The nonwoven fabric to be processed may contain other structural fibers in addition to the thermoplastic resin fibers. Examples of other structural fiber systems include natural fibers (for example, wool, cotton, etc.), regenerated fibers (for example, rhenium, acetate, etc.), and inorganic fibers (for example, glass fiber, carbon fiber, etc.). Examples of the thermoplastic resin fiber system include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, and ionic polymer resin. Polyolefins such as polyester; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polylactic acid; polyamines, such as nylon. Non-woven fabrics can also be mixed with core / sheath fibers, side-by-side fibers, island / sea fibers, etc .; composite fibers; hollow fibers; flat, Y-shaped, C-shaped special-shaped fibers; latent or apparently curled Shrinked three-dimensional crimped fibers; split fibers that are split by physical loads such as water flow, heat, and embossing.

Examples of the manufacturing method of the non-woven fabric include a method of forming a fabric (fleece) and physically / chemically combining the fibers, and examples of the method of forming the fabric include a spinning method and a dry method (comb) Carding method, spinning method, melt-blown method, airlaid method, etc.), wet method, etc. Examples of bonding methods include: spunbond method, Chemical adhesion method, needle rolling method, suture method, water needle method, etc. In addition to the nonwoven fabric manufactured as described above, a water jet nonwoven fabric formed into a sheet shape by a water entanglement method may be used.

In addition, in terms of the concealability of the excretory fluid when used in an absorbent article, fibers of a non-woven fabric used for an object to be processed may be opaque, particularly fibers having high whitening properties. For example, opaque fibers may be used. Light transmitted through the inhibitor. Examples of the light transmission inhibitor system include inorganic fillers. Examples of the inorganic filler system include titanium oxide, calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, aluminum hydroxide, and magnesium hydroxide. , Zinc oxide, calcium oxide, aluminum oxide, mica, glass powder, white sand ball (shirasu balloon), zeolite, and silicate clay. These systems can be used in combination of two or more. In particular, titanium dioxide is preferred in terms of step characteristics and the like in the general fiber manufacturing stage.

In addition, for thermoplastic resin fibers, antioxidants, light stabilizers, ultraviolet absorbers, neutralizers, nucleating agents, epoxy stabilizers, lubricants, antibacterial agents, flame retardants, and antistatic agents can be added as needed. , Pigments, plasticizers and other additives. The thermoplastic resin fiber is preferably hydrophilized by a surfactant, a hydrophilic agent, or the like.

Furthermore, the basis weight of the nonwoven fabric to be processed is usually 10 to 100 g / m ² , preferably 15 to 75 g / m ² , and more preferably 20 to 50 g / m ² . The thickness of the nonwoven fabric is usually 0.1 to 5 mm, preferably 0.5 to 3 mm, and more preferably 0.8 to 2 mm.

In this embodiment, the preheating device 61 can be equipped with a pair of upper and lower heating rollers 61a and 61b, and the non-woven fabric 51 of the object to be processed is wound around the heating roller 61b under the rotation and heated The heating roller 61a is transferred to the upper rotating roller 61a, and the non-woven fabric 51 to be heated is heated again by the heating roller 61a.

In addition, the shaping device 62 is provided with a pair of upper and lower extension rollers 63 and 64. As shown in FIG. 6, the upper extension roller 63 is provided with a ridge 63a and a plurality of rows of concave grooves 63b. The protruding ribs 63a are arranged at a certain interval in the width direction of the roller, and a plurality of rows are provided in parallel with each other along the outer peripheral surface of the extending roller 63 above; the recessed grooves 63b are provided at adjacent protruding Between edges 63a, 63a.

On the other hand, the lower extension roller 64 is provided on the outer peripheral surface with A plurality of pins 64a are provided to be engaged with the recessed grooves 63b of the extension roller 63 above. As shown in FIG. 8, the pins 64 a are arranged in the width direction of the roller so as to avoid contact with the protrusions 63 a of the upper extending roller 63 at a certain interval, and are arranged in the circumferential direction of the roller. It is arranged substantially linearly at regular intervals along the outer peripheral surface. As shown in FIG. 7, the lower extension roller 64 in this embodiment has a structure in which a plurality of pins 64 a are arranged in a staggered grid pattern on the outer peripheral surface of the lower extension roller 64.

When the manufacturing method of the nonwoven fabric 1 for absorbent articles is implemented using the manufacturing apparatus 50 which has the said structure, a preheating step and a shaping step are performed sequentially, and this preheating step is about unwinding from the unwinding device 52 Pre-heating is applied to the non-woven fabric 51 of the subsequent processing object; in this forming step, the non-woven fabric 51 of the object to be processed after the pre-heating step is extended to shape processing.

The preheating step is performed by unwinding the non-woven fabric 51 of the processing object which is unwound from the unwinding device and conveyed along the conveying direction MD, and sequentially contacts the upper and lower pair of heating rollers 61a, The outer peripheral surface of 61b is preheated by heating the nonwoven fabric 51 to be processed.

Although the preheating temperature depends on the type of the thermoplastic resin fibers that constitute the non-woven fabric to be processed, for example, in the case of core-sheath type composite fibers of polyethylene terephthalate (PET) and high-density polyethylene (HDPE) Preferably, the temperature of the outer peripheral surface of the heating roller is set to about 60 to 120 ° C.

The forming step is to feed the non-woven fabric 51 of the processing object that has been transported through the preheating step into one of the forming devices 62 for meshing. Between the upper and lower pair of extension rollers 63 and 64 rotating while rotating, the non-woven fabric 51 of the object to be processed is engaged with the ribs 63a and recessed grooves 63b of the upper extension roller 63 and the extension roller 64 below. The pins 64a are extended and shaped. In addition, when the forming step is performed, it is preferable to perform the forming while heating the stretching rolls 63 and 64 to 60 to 120 ° C. in order to facilitate the forming.

At this time, the upper extension roller 63 presses the portion where the ridge 63a is in contact with the nonwoven fabric 51 to be processed in the direction of the lower extension roller 64, thereby shaping the convex portion 4.

On the other hand, the lower extension roller 64 presses the non-woven fabric 51 of the processing object at the front end of the plurality of pins 64a aligned in a row in the circumferential direction toward the same recessed groove 63b of the upper extension roller 63.

At this time, a portion of the non-woven fabric 51 to be processed, which is drawn into the recessed groove 63 b in a non-contact state with the pin 64 a, becomes the groove portion 5. In addition, the portion in contact with the front end portion of the pin 64a is forcibly pressed into the recessed groove 63b for forming, thereby forming a first portion having a direction extending in a direction in which the convex portion 4 and the groove portion 5 extend. One peripheral surface 8 a, a second peripheral surface 8 b extending in the roll width direction, and a recessed portion 7 of the bottom 9.

In addition, if the formation of the bottom 9 is described more specifically, when the pin 64a presses the non-woven fabric 51 to be processed, the portion of the non-woven 51 of the object to be pressed by the front end of the pin 64a becomes the bottom 9. At this time, when the bottom 9 is formed, since the front end portion of the pin 64 a compresses the non-woven fabric 51 to be processed, the fiber density of the bottom 9 will increase, and finally the fiber density will be higher than that of the convex portion 4. Thus, at the end The portion 9 has a higher fiber density than the convex portion 4 and has a higher rigidity than the convex portion 4. In addition, the bottom 9 is formed by compressing the nonwoven fabric 51 to be processed by the front end portion of the pin 64a. Therefore, the thickness of the nonwoven fabric 51 is smaller than that before processing.

Furthermore, in this step, when the recessed portion 7 is formed, a large pressure is applied to the nonwoven fabric 51 to be processed by the pin 64a of the lower extension roller 64, and on the other hand, the projection 4 is formed. At this time, the non-woven fabric 51 of the processing object is applied with a weaker pressure than the pin 64a by the outer peripheral surface of the rib 63a of the upper extension roller 63. Therefore, during the formation of the concave portions 7 and the convex portions 4, the bottoms of the concave portions 7 are formed to be thinner than the tops of the convex portions 4 due to the difference in applied pressure.

Further, in the nonwoven fabric 51 to be processed, the both ends of the width direction (roller width direction) of the front end portion of the contact pin 64a are fitted to the protruding roller 63a to press the nonwoven fabric 51 to be stretched downward to the extension roller 64. In the tension that occurs in the direction, the pin 64a pulls the thermoplastic resin fiber forming the first peripheral surface 8a away or breaks the fiber to form the broken fiber 13 having the broken end portion 13a.

Thereby, the hole portion 11 including the broken end portion 13 a of the broken fiber 13 is formed in the recessed portion 7. In addition, a part of the thermoplastic resin fibers remains in a state that crosses the internal space 11a of the hole portion 11, and a part of the broken ends 13a of the broken fibers 13 is in a state that extends into the internal space 11a.

Here, since the hole portion 11 is formed in the direction of the conveying direction MD of the nonwoven fabric to be processed, that is, the rotation of the extension rollers 63 and 64 The direction is the direction in which the convex portion 4 and the groove portion 5 are extended. Therefore, the hole portion 11 is also formed on the peripheral surface along the direction in which the convex portion 4 and the groove portion 5 are extended, that is, the first peripheral surface 8a. .

The non-woven fabric after the forming step is formed with a convex portion 4 and a groove portion 5 including a concave portion 7 to complete the non-woven fabric 1 as an absorbent article. This non-woven fabric 1 is then used as a top sheet of disposable absorbent articles such as disposable diapers or sanitary napkins, incontinence pads, sanitary pads, etc., or used as a leak-proof wall, or attached to disposable sheets The outer surface of the back sheet of a paper diaper.

The non-woven fabric 1 for an absorbent article having the aforementioned structure is attached to the groove bottom 6 of the groove portion 5 provided between the convex portions 4 and 4 and has a bottom 9 which is lower than the groove bottom 6 and is provided with A plurality of recesses 7 are provided discontinuously in the first direction X of the non-woven fabric 1, and a hole 11 is provided on the first peripheral surface 8a of the recess 7. The hole 11 is provided without melting thermoplastic resin fibers. Forming the peripheral edge portion 12.

Therefore, since the degree of freedom of movement of the convex portion 4 or the fibers of the convex portion 4 is increased, and the tensile force of the convex portion 4 is relaxed by the hole portion 11, the entire convex portion 4 becomes soft. Softness is felt when the nonwoven fabric 1 is pressed, and smoothness is felt when the skin slides in the plane direction of the nonwoven fabric.

Furthermore, since the fiber density of the bottom portion 9 of the recessed portion 7 is higher than that of the convex portion 4, the rigidity of the bottom portion 9 is less likely to deform significantly than the convex portion 4. Therefore, when the nonwoven fabric 1 is used in an absorbent article, The rigidity of the bottom 9 prevents the non-woven fabric 1 and even the large deformation of the absorbent article. and In addition, since the bottom portion 9 is formed in a planar shape on the second surface 3 side, it can stably contact the ground with other members of the absorbent article and support the nonwoven fabric 1 stably. As a result, since the bottom 9 itself conforms the non-woven fabric, and when it is used in an absorbent article, the bottom 9 of another member that is in surface contact with the absorbent article supports the entire non-woven fabric 1 through the peripheral surface 8, so the non-woven fabric 1 can be made. The overall shape is stably maintained, and the soft touch of the nonwoven fabric 1 can be maintained and secured.

In addition, the hole portion 11 of the recessed portion 7 has a peripheral edge portion 12 that can be formed without melting the fibers. The peripheral edge portion 12 includes the broken end portion 13a of the broken fiber 13 formed by breaking. There is no conventionally hardened portion by melting. Thereby, the excellent soft and hard feeling (softness in the thickness direction) and the excellent rough feeling (smoothness in the plane direction) of the nonwoven fabric 1 can be further improved (soft and smooth), and an extremely soft feeling can be imparted to the skin.

In the foregoing embodiment, the hole portion 11 of the recessed portion 7 is provided on the pair of first peripheral surfaces 8a formed along the first direction X, but the hole portion may be provided on the first peripheral surface 8a along the second direction. The pair of second peripheral surfaces formed by the embodiments may have a structure provided on any one of the peripheral surfaces.

Further, in the foregoing embodiment, the hole portion 11 is disposed near the bottom portion 9 of the peripheral surface of the recessed portion 7, but the position of the hole portion on the peripheral surface does not necessarily need to be close to the bottom portion, so that the non-woven fabric is not damaged. It can be arbitrarily set within the range of flexibility.

In addition, in the aforementioned embodiment, the peripheral edge portion 12 of the hole portion 11 includes the broken end portion 13 a including the broken fiber 13, and the broken end portion 13a is formed by breaking the thermoplastic resin fibers in the nonwoven fabric 1. However, the peripheral edge portion of the hole portion does not necessarily include the broken end portion of the broken fiber as long as the thermoplastic resin fibers forming the peripheral edge portion are not hardened by melting.

Furthermore, in the aforementioned embodiment, although a part of the fibers 14 of the thermoplastic resin fiber straddles the inner space 11a of the hole portion 11, there may be no fiber that straddles the inner space of the hole portion in this way. In addition, as in the aforementioned embodiment, the broken end portion of the broken fiber may not extend into the internal space of the hole portion.

In the foregoing embodiment, the recessed portion 7 is formed in a substantially rectangular parallelepiped shape. However, the shape of the recessed portion may be any shape such as a columnar shape or a corner column shape.

Furthermore, in the aforementioned embodiment, the convex portion 4 extends continuously in the first direction X of the nonwoven fabric 1. However, it is not necessary for the convex portion to extend continuously in the first direction of the nonwoven fabric, and it may be intermittent. However, at this time, it is preferable that the concave portion is provided at the bottom of the groove portion of the groove portion surrounded by the continuous portion of the convex portion. Therefore, since the convex portion easily contacts the skin first, on the contrary, the concave portion is difficult to contact. It is more difficult to feel a foreign body or discomfort due to the recess.

Claims (6)

A non-woven fabric for an absorbent article has a first surface and a second surface opposite to the first surface, and includes a convex portion protruding toward the first surface side and a groove portion recessed toward the second surface side. The non-woven fabric contains thermoplastic resin fibers, wherein the convex portion is extended toward the first direction of the surface of the non-woven fabric, and is separated from the surface of the non-woven fabric in a second direction orthogonal to the first direction. A plurality of rows are provided at predetermined intervals. The groove portion is provided in a space extending between the convex portions adjacent in the second direction toward the first direction. At the bottom of the groove of the groove portion, the groove portion is provided. The groove portion has a bottom portion closer to the second surface side than a groove bottom portion of the groove portion, and is provided with a plurality of recessed portions discontinuously provided in the first direction. At least a part of a peripheral surface of the recessed portion is provided with a through hole. The hole portion of the second surface and the bottom portion of the concave portion have a higher fiber density than the convex portion, and at least the second surface side is formed into a planar shape. The nonwoven fabric for absorbent articles according to item 1 of the scope of patent application, wherein the recessed portion has a first peripheral surface formed as a pair along the first direction, and along the second direction. The pair of second peripheral surfaces are formed in a manner such that the hole portion is provided only on the first peripheral surface, and the second peripheral surface is continuous with the groove bottom of the groove portion. For example, in the non-woven fabric for absorbent articles according to the first or second scope of the patent application, the thickness of the bottom portion of the recessed portion is smaller than the thickness of the most protruding portion of the protruding portion toward the first surface side. The nonwoven fabric for absorbent articles according to item 1 or item 2 of the scope of patent application, wherein the fiber density of the bottom portion of the concave portion is 1.3 to 1.5 times the fiber density of the convex portion. The nonwoven fabric for absorbent articles according to item 1 or 2 of the scope of patent application, wherein the height from the first surface side of the groove bottom portion to the first surface side of the bottom portion of the recess portion The height dimension is 50 to 80% of the dimension from the height of the first surface side of the bottom of the groove to the height of the top of the convex portion. The nonwoven fabric for absorbent articles according to item 1 or 2 of the scope of patent application, wherein the interval between the aforementioned convex portion and other adjacent convex portions is 0.25 to 5 mm.