TW202103664A - Stretchable sheet, absorbent article equipped with said stretchable sheet, and manufacturing method for said stretchable sheet - Google Patents

Abstract

According to the present invention, a first sheet (11) and a second sheet (12) are positioned on an opposite side with an elastic member (13) therebetween and joined by a plurality of fused sections (15) which are formed at intervals in the extending direction of the elastic member (13). The elastic member (13) is fixed by only the friction between both the sheets (11, 12) in a space defined by the fused sections (15), the first sheet (11), and the second sheet (12). The second sheet (12) has, in a region overlapping the elastic member (13) in the thickness direction, a void rate varying region (20) such that a void rate between constituent fibers is relatively higher in a central portion than in both side portions. In the void rate varying region (20), a portion of the constituent fibers is in a state of losing a fibrous shape and being melted and solidified, and the remaining portion of the constituent fibers maintains a fibrous shape.

Description

Stretchable sheet, absorbent article provided with the stretchable sheet, and manufacturing method of the stretchable sheet

The present invention relates to a stretchable sheet, an absorbent article provided with the stretchable sheet, and a method for manufacturing the stretchable sheet.

As a sheet used in absorbent articles such as diapers, there is known a stretchable sheet in which an elastic member such as a rubber thread is joined in an extended state between two sheets. For example, Patent Document 1 describes a stretchable sheet in which a plurality of elastic stretchable members arranged in parallel are sandwiched between non-woven fabrics, and the non-woven fabrics are intermittently welded to each other to fix the elastic stretch member. The elastic elastic member is arranged in a cross-sectional space closed by the welded parts of the non-woven fabrics near both sides in the diameter direction, and is fixed by the friction force between the outer surface of the elastic elastic member and the sheet forming the closed space .

Patent Document 2 describes a stretchable sheet in which an elastic member is attached between a pair of sheet-shaped members. This kind of sheet material can be obtained by the following steps, that is, between a pair of sheet-like members, the end of the stretched elastic member is fixed to each sheet-like member with an adhesive, and the pair of sheet-like members is opposed to each other. After the faces are welded to each other, cut them off. The elastic member expands in the CD (Cross Direction) direction along with the above-mentioned cutting, is clamped by the welded parts on both sides of the elastic member, and is installed between a pair of sheet-like members. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-154998 [Patent Document 2] International Publication No. 2018/122970

The present invention relates to a stretchable sheet having a first sheet including a fiber sheet, a second sheet that is arranged opposite to the first sheet and includes a fiber sheet, and is arranged in an elongated state between two sheets. The elastic member extending in one direction between the sheets has elasticity along the extending direction of the elastic member. The first sheet and the second sheet are preferably joined by a plurality of fusion portions, the fusion portions being located on both sides of the elastic member via the elastic member and spaced apart along the extending direction of the elastic member form. The elastic member is preferably in the space formed by the fusion portion, the first sheet and the second sheet located on both sides of the elastic member via the elastic member, and only by the surface of the elastic member and the second sheet. The first sheet and the second sheet are rubbed and fixed between the two sheets. Preferably, when the stretchable sheet is viewed in a cross-section in a direction orthogonal to the extending direction of the elastic member at the position where the fusion portion is formed, the length of the first sheet and the elastic member in contact is longer than that of the second sheet. The length connected with the elastic member is long. Preferably, when the stretchable sheet is viewed in a cross-section in a direction orthogonal to the extending direction of the elastic member at the position where the fusion portion is formed, the second sheet has a region overlapping with the elastic member in the thickness direction A porosity change area in which the center portion in the above-mentioned orthogonal direction has a relatively higher porosity between the constituent fibers than the two sides across the center portion. Preferably, in the above-mentioned porosity change region, a part of the constituent fibers loses the fiber shape and becomes a melted and solidified state, and the remaining part of the constituent fibers maintains the fiber shape.

In addition, the present invention relates to an absorbent article, which includes an absorbent body and an exterior body located on the non-skin facing side of the absorbent body. It is preferable that the said exterior body contains the said stretchable sheet.

In addition, the present invention relates to a method for manufacturing a stretchable sheet. The stretchable sheet is an elastic member that extends in one direction between two facing sheets and has stretchability in the direction in which the elastic member extends. In one embodiment, it is preferable that the fusion portion of the two sheets is arranged close to the elastic member on both sides of the elastic member in the width direction with the elastic member interposed therebetween to form a fusion portion pair, and the fusion portion pair A plurality of the elastic members are intermittently arranged in the extending direction of the elastic member. In one embodiment, it is preferable that the elastic member is compressed by a plurality of the fusion portions in a state of being stretched at a specific elongation in the extension direction of the elastic member. In one embodiment, it is preferable to have a fusion part forming step in which the elastic member is arranged between two sheets in a state of being stretched in one direction, and the stretched elastic member is interposed in the width direction of the elastic member. A plurality of locations on both sides join the two sheets to each other to form a plurality of fusion-bonded part pairs. In one embodiment, it is preferable to have an elastic member relaxation step, which is to release the stretched state of the elastic member to relax the elastic member, and the elastic member is made elastic by the increase in the width direction length of the elastic member accompanying the relaxation. The adhesion between the part of the member sandwiched between the pair of fusion portions and the pair of fusion portions is improved compared to before relaxation, whereby the fusion portion pair is used to pinch the elastic member in a state of being stretched with a specific elongation. In one embodiment, it is preferable that, regarding the elastic member, the elongation rate in the extended state in the fusion portion forming step is higher than the elongation rate in the natural state of the stretchable sheet as a manufactured product.

In addition, the present invention relates to an absorbent article, which has a longitudinal direction extending from the wearer's abdominal side to the back side through the crotch portion and a transverse direction perpendicular to the longitudinal direction, and is provided with an absorbent body that absorbs and retains excrement. In one embodiment, it is preferable to include a stretchable sheet having stretchability in the above-mentioned lateral direction. In one embodiment, it is preferable that the stretchable sheet includes two facing sheets and an elastic member arranged between the two sheets and extending in the transverse direction. In one embodiment, it is preferable that the fusion portions of the two sheets are arranged on both sides of the elastic member in the width direction via the elastic member in contact with the elastic member to form a pair of fusion portions, and the fusion A plurality of part pairs are intermittently arranged in the above-mentioned lateral direction. In one embodiment, it is preferable that the elastic member is compressed by a plurality of the fusion part pairs in a state of being stretched at a specific elongation in the lateral direction. In one embodiment, it is preferable that an elastic member non-arrangement area where the elastic member is not arranged exists at the end of the transverse direction of the stretchable sheet. In one embodiment, it is preferable that the elastic member non-arrangement area includes a plurality of the fusion portion pairs intermittently arranged in the lateral direction, at least a lateral outermost fusion portion pair located at the outermost side of the lateral direction, and the outermost fusion portion pair in the lateral direction The outer fusion part pair is the closest fusion part pair in the transverse direction. In one embodiment, it is preferable that the lateral ends of the elastic member are located in the pair of fusion portions.

In addition, the present invention relates to a stretchable sheet manufactured by the above-mentioned manufacturing method of the present invention.

When the stretchable sheet is used to form the outer body of the diaper, from the viewpoint of improving the conformability to the wearer’s abdomen, it is ideal to set the direction of extension of the elastic member to be consistent with the wearer’s The state of the same direction of the abdomen and circumference of the person. On the other hand, when a wearer in a standing position wears a diaper, he usually performs an action of passing the leg through the leg opening and then stretching the vicinity of the waist opening of the diaper to the waist side. Regarding the stretchable sheet described in Patent Documents 1 and 2 described above, if the sheet is stretched in a direction orthogonal to the extending direction of the elastic member by the above-mentioned action, the elastic member fixed between the welded parts may fall off. , The stretchability of the stretchable sheet is reduced, which may impair the conformability of the abdominal part of the diaper.

In addition, the stretchable sheet described in Patent Documents 1 and 2 has a structure in which an elastic member is pinched by the joint between the sheets, and the elastic member is fixed by the frictional force between the surface of the elastic member and the sheet. The stretchable sheet for this sheet was previously manufactured as follows. That is, an elongated laminated body formed by arranging an elastic member in an elongated state receiving a tensile force in that direction between two continuous sheets in the conveying direction is produced, and the elasticity of the laminated body being conveyed The two ends of the member in the extending direction are subjected to fusion processing such as embossing with heat, ultrasonic fusion processing, etc., whereby a plurality of fusion portions of the two sheets are formed along the extending direction of the elastic member ( Junction), and then the laminate is cut into a specific product unit length to obtain the above-mentioned stretchable sheet.

In the previous manufacturing method of the stretchable sheet, before the fusion process is performed, the elastic member that should be arranged linearly between the two sheets is meandering. Therefore, the elastic member and the sheet may be combined during the fusion process. The problem of pressing and cutting. In particular, the linear or rope-like elastic members commonly used in stretchable sheets have a smaller tensile force (the lower the elongation rate) during transport, the easier it is to bend. Therefore, the elastic members are manufactured with relatively low elongation In the case of a stretchable sheet with a fixed rate, the problem of the above-mentioned cutting of the elastic member becomes more serious. In Patent Documents 1 and 2, there is no description of an effective solution to this problem.

Therefore, the present invention relates to a stretchable sheet that can eliminate the disadvantages of the above-mentioned prior art, a method for manufacturing the stretchable sheet, and an absorbent article provided with the stretchable sheet.

Hereinafter, the present invention will be described with reference to the drawings according to its preferred embodiments. Fig. 1 shows an embodiment of the stretchable sheet of the present invention. This figure is a top view of a partial fracture when the stretchable sheet 10 is stretched to the maximum elongation state. The so-called maximum elongation state means that the first sheet 11 and the second sheet 12 constituting the stretchable sheet 10 are stretched until the following elastic members are stretched and become the design dimensions (to eliminate all the influence of the elastic members) The state is expanded to the size of a flat surface). In addition, in the broken portion shown in FIG. 1, the following first fusion portions 15a, 15b are omitted.

As described above, the stretchable sheet 10 has the first sheet 11 and the second sheet 12 arranged to face the first sheet. A plurality of linear elastic members 13 such as rubber threads are arranged between the two sheets 11 and 12. Specifically, a plurality of elastic members 13 are intermittently arranged with a certain interval. The plurality of elastic members 13 extend in one direction without intersecting each other. FIG. 1 shows a state where the elastic members 13 extend parallel to each other. Each elastic member 13 is fixed between the two sheets 11 and 12 in an extended state. In the following description, the extension direction of the elastic member 13 is also referred to as the X direction. In addition, the direction orthogonal to the extending direction of the elastic member 13 is also referred to as the Y direction.

The first sheet 11 includes a fiber sheet. The first sheet 11 may be a hydrophilic fiber sheet or a hydrophobic fiber sheet. The hydrophilic fiber sheet is one that is taken from any part of the fiber sheet and the contact angle between the constituent fiber and water is less than 90 degrees. The hydrophobic fiber sheet is one where the contact angle between constituent fibers and water taken from any part of the fiber sheet is 90 degrees or more. The measurement of the contact angle between the fiber and water can be performed according to, for example, the method described in Japanese Patent Laid-Open No. 2015-142721. From the viewpoint of facilitating the formation of the fusion portion described below, the first sheet preferably contains a hydrophilic non-woven fabric containing fibers obtained by imparting hydrophilicity to synthetic fibers containing a heat-fusible resin as constituent fibers. Examples of heat-fusible resins include polyethylene, polypropylene, and the like. The fiber constituting the fiber sheet may be a core-sheath type composite fiber or the like containing a heat-fusible resin only on the surface.

The second sheet 12 also includes a fiber sheet. Like the first sheet 11, the second sheet 12 may be a hydrophilic fiber sheet or may be a hydrophobic fiber sheet. The hydrophobic fibrous sheet is one in which the contact angle between constituent fibers and water taken from any part of the fibrous sheet is 90 degrees or more. From the same viewpoint as the above, the second sheet 12 is preferably a sheet containing the above-mentioned synthetic fiber containing the heat-fusible resin as the constituent fiber. In the first sheet 11 and the second sheet 12, the forming materials may be the same, or may be different.

As shown in FIG. 1, the 1st sheet|seat 11 and the 2nd sheet|seat 12 are joined by a plurality of fusion parts. The two sheets 11, 12 are fused at the fusion part. The so-called "fusion" means that a molten part is generated in the two sheets 11, 12 by heat, and the molten part is mixed with each other and then cooled to integrally join the part. The stretchable sheet 10 of the present embodiment has a pair of first fusion portions 15a, 15b located on both sides of the elastic member 13 via the elastic member 13 and a pair of first fusion portions 15a, 15b located in the Y direction. The second fusion portions 16a and 16b between 15b serve as fusion portions. The respective fusion portions of the first fusion portions 15a, 15b and the second fusion portions 16a, 16b are formed at intervals along the extending direction of the elastic member 13, that is, in the X direction. The 2nd fusion|fusion part 16a, 16b is a pair of 1st fusion|fusion part 15a, 15b in the Y direction, and two are arrange|positioned side by side. The fusion portions 15a, 15b, 16a, and 16b are spaced apart from each other, and are arranged such that they are arranged in a row along the Y direction in sequence. By disposing the fusion part in this way, the following fold structure can be formed on each surface of the stretchable sheet 10.

The aforementioned pair of first fusion portions 15a and 15b are also collectively referred to as the first fusion portion pair 15. A plurality of first fusion portion pairs 15 are intermittently arranged in the extending direction (X direction) of each of the plurality of elastic members 13. The two first fusion portions 15a, 15b constituting a first fusion portion pair 15 are arranged opposite to each other in the Y direction via an elastic member 13, and each fusion portion 15a, 15b is in contact with the elastic member 13, and more Specifically, as shown in FIG. 2, the elastic member 13 is plunged and pressed.

The above-mentioned second fusion portion 16a, 16b arranged side by side with two are also collectively referred to as the second fusion portion pair 16. As shown in FIG. 1, the second fusion portion pair 16 is arranged between a plurality of elastic members 13 intermittently arranged in the Y direction, and is not in contact with the elastic members 13. In addition, a plurality of second fusion portion pairs 16 are intermittently arranged in the X direction, and are arranged at the same position as the first fusion portion pair 15 in the X direction. That is, in the present embodiment, in the stretchable sheet 10, the first fusion portion pairs 15 that are in contact with the elastic member 13 and the second fusion portion pairs 16 that are not in contact with the elastic member 13 are alternately arranged in the Y direction, The two fusion part pairs 15 and 16 are respectively intermittently arranged in the X direction. If the second fusion portion pair 16 that is not related to the fixation of the elastic member 13 is formed in the stretchable sheet 10 in this way, it is easy to form on both sides of the stretchable sheet 10 (the surface on the side of the first sheet 11 and the side of the second sheet 12). The surface) forms the following fold structure. Furthermore, in the present invention, the second fusion portion pair 16 (the fusion portion pair that is not in contact with the elastic member 13) is not essential, and may not exist. The stretchable sheet 10A constituting the disposable diaper 1 (see FIG. 15) described below does not have the second fusion portion pair 16 (second fusion portion 16a, 16b).

The plurality of elastic members 13 in the stretchable sheet 10 are respectively clamped between the two sheets 11 and 12 by the plurality of first fusion portion pairs 15. More specifically, as shown in FIG. 2, each elastic member 13 is formed between a first fusion portion 15a and the other first fusion portion 15b constituting the first fusion portion pair 15, and is separated by the two fusion portions 15a, 15b. Both sides in the Y direction are pressed and plastically deformed, that is, they are pressed by the first fusion portion pair 15.

In more detail, the elastic member 13 is located between the first fusion portions 15a, 15b located on both sides of the elastic member 13 with the elastic member 13 interposed therebetween. It is fixed between the two sheets 11 and 12 by friction. Between the first fusion portions 15a, 15b, a space partitioned by the first fusion portions 15a, 15b, the first sheet 11, and the second sheet 12 is formed in a cross section along the Y direction. In this space, the elastic member 13 is fixed between the two sheets 11 and 12 only by the friction between the surface of the elastic member 13 and the first sheet 11 and the second sheet 12. That is, in the stretchable sheet 10, the elastic member 13 is not fixed to the first sheet 11 and the second sheet 12 by a bonding method such as an adhesive or fusion. In the stretchable sheet 10, the elastic member 13 and the first sheet 11 and the elastic member 13 and the second sheet 12 are not fused to each other. Thereby, the stretchable sheet 10 can be formed by maintaining the good texture or air permeability that the first sheet 11 and the second sheet 12 originally have. In addition, the stretchable sheet 10 becomes highly stretchable.

As described above, the elastic member 13 is located in the space along the Y direction between the pair of first fusion portions 15a, 15b, and is fixed by friction between the surface of the elastic member 13 and the first sheet 11 and the second sheet 12 In two sheets 11,12. As shown in FIG. 2, which is an enlarged view of the main part of FIG. 1, the side edge 151a on the side of the elastic member 13 in one first fusion portion 15a and the side edge 151b on the side of the elastic member 13 in the other first fusion portion 15b The interval between the first fusion portion interval D (hereinafter also referred to as "the interval D between the first fusion portion pair 15") is narrower than the diameter d1 of the elastic member 13 in the maximum elongation state of the stretchable sheet 10, only The elastic member 13 is fixed between the first sheet 11 and the second sheet 12 by friction on the surface of the elastic member 13 generated in the space by the pinching of the pair of first fusion portions 15a, 15b. In detail, after the elastic member 13 is placed in an extended state, the two sheets 11 and 12 are intermittently fused or joined in the extension direction in the vicinity of both ends of the elastic member 13 in the width direction (Y direction). Thereby, after arranging a plurality of first fusion portion pairs 15 including the first fusion portion 15a, 15b along the elastic member 13, the elastic member 13 and the two sheets 11, 12 are cut, etc., and the stretched state of the elastic member 13 is released When the elastic member 13 relaxes and expands in the Y direction, the expansion of the elastic member 13 is restricted by the first fused portions 15a, 15b located on both sides of the elastic member 13 in the Y direction at the arrangement position of the first fused portion pair 15 Therefore, the elastic member 13 is in a state of being pinched by the first fusion portions 15a and 15b (refer to FIG. 2). In addition, in FIG. 2, the elastic member 13 appears to be joined to the pair of first fusion portions 15a and 15b, but in reality, the elastic member 13 is not joined to the pair of first fusion portions 15a and 15b.

From the viewpoint of the above-mentioned space between the pair of first fusion portions 15a and 15b, the elastic member 13 is reliably fixed only by the friction between the surface of the elastic member 13 and the first sheet 11 and the second sheet 12, The first fusion portion interval D is when the diameter of the elastic member 13 in the relaxed state of the stretchable sheet 10 is set to d2 (refer to FIG. 2), the value of d2/D is preferably 1.1 or more, and more preferably 1.2 Above, more preferably 1.3 or more. The higher the value of d2/D, the higher the frictional force between the surface of the elastic member 13 and the first sheet 11 and the second sheet 12, which is better in this respect. The diameter d2 of the elastic member 13 in the relaxed state of the stretchable sheet 10 refers to the diameter of the elastic member 13 at the portion where the elastic member 13 is not pinched in the relaxed state of the stretchable sheet 10.

In the case of expressing the above-mentioned d2 by the fineness, from the viewpoint of ensuring the stretchability of the stretchable sheet 10, the fineness is preferably 155 dtex or more, and more preferably 310 dtex or more. Moreover, it is preferably 1240 dtex or less, and more preferably 940 dtex or less. The fineness of the elastic member 13 is preferably 155 dtex or more and 1240 dtex or less, and more preferably 310 dtex or more and 940 dtex or less.

As shown in FIG. 3, when the stretchable sheet 10 is viewed along the direction orthogonal to the extending direction of the elastic member 13 at the position where the fusion portion 15a, 15b is formed, that is, the Y-direction cross-section in the figure, the first sheet The length of 11 and the elastic member 13 is longer than the length of the second sheet 12 and the elastic member 13. The reason is that in the elastic member 13 viewed in cross-section, the portion on the side of the first sheet 11 is oriented outward in the thickness direction Z of the stretchable sheet 10 compared to the portion on the side of the second sheet 12 of the elastic member 13 The bulge, when the elastic member 13 is divided into two equal parts in the thickness direction Z in the cross-sectional view, becomes an asymmetric shape between the second sheet 12 side and the first sheet 11 side of the elastic member 13 (refer to FIG. 3) . In other words, in the cross-sectional view, the elastic member 13 is located between the pair of fusion portions 15a, 15b, has a substantially flat portion on the second sheet 12 side, and has a portion swelling outward in the thickness direction on the first sheet 11 side . Also, regarding the second sheet 12 side of the elastic member 13, the portion between the first fusion portion 15a, 15b when viewed in cross-section along the Y direction and the portion other than the portion between the first fusion portion 15a, 15b when viewed in the cross-section Ratio becomes a roughly flat part.

Furthermore, as shown in FIG. 3, in the elastic sheet 10, the 2nd sheet|seat 12 has the porosity change area|region 20 in the area|region overlapping with the elastic member 13 in the thickness direction Z. As shown in FIG. The porosity change region 20 is a region in which the center portion M in the Y direction constitutes a region having a relatively higher porosity between the fibers than the side portions S and S that sandwich the center portion M. The central portion M is the central area when the area where the second sheet 12 and the elastic member 13 are overlapped is divided into three equal parts in the Y direction, and the two side portions S and S are located on both sides of the central portion M. area. The porosity change region 20 only needs to have a higher porosity in the central part M than in each of the side parts S and S, and from the outer end in the Y direction toward the inner side, that is, from the side S side toward the central part M side, the gap is The rate can be increased in stages, and the void rate can also gradually increase. When the porosity in the porosity change region 20 changes step by step, the porosity change region 20 has a plurality of regions with different porosity. In the above-mentioned porosity change region 20, the porosity is different from each other, and the interface between two adjacent regions in the Y direction is not clear. The above-mentioned "unclear interface between the two regions" refers to a state where the fiber shape part or the melted and solidified part of the fiber is continuous in the Y direction, and the boundary between the two regions becomes unclear. In the porosity change region 20, the porosity of the central portion M may be as long as the porosity in the entire thickness direction thereof is higher than the porosity in the entire thickness direction of each of the side portions S and S. That is, the central portion M of the porosity change region 20 may have a form in which the porosity is higher than the two side portions S and S throughout its thickness direction, or it may have a portion having a porosity that is locally different in the thickness direction but serves as the thickness. The overall porosity of the direction is higher than the shape of S and S on both sides. The porosity of the central portion M of the porosity change region 20 may be approximately the same as the porosity of other regions. The other area refers to the area other than the porosity change area 20 in the second sheet 12, that is, the area other than the area overlapping the elastic member 13 in the thickness direction Z, and the first sheet 11 and the second sheet 12 Areas that are unjoined and contain fibers. Therefore, the regions where the fibers melt and lose their original fiber state, namely, the first fusion portions 15a and 15b and the second fusion portions 16a and 16b do not match the other regions. On the other hand, the porosity of the side portions S and S of the porosity change region 20 is lower than the porosity of other regions. That is, the void ratio between the constituent fibers in the entire void ratio change region 20 is lower than the void ratio between the constituent fibers in the other regions of the second sheet 12.

The stretchable sheet has a porosity change area 20 in the second sheet 12. The porosity change area 20 is formed on the second sheet 12 located between the pair of first fusion portions 15a and 15b in the Y direction, and opposes the first sheet 11 with the elastic member 13 interposed therebetween. The porosity change area 20 has a lower porosity on both sides S and S than other areas, and the porosity change area 20 and the elastic member 13 are not fused with each other. In the stretchable sheet 10 shown in FIG. 3, the first sheet 11 has a region 21 overlapping the elastic member 13 in the thickness direction Z. The region 21 is composed of a sheet material arranged to face the porosity change region 20 with the elastic member 13 interposed therebetween. This area is also referred to as an elastic member overlap area 21.

When viewed in the cross section shown in FIG. 3, the surface of the second sheet 12 facing the elastic member 13 is in close contact with the above-mentioned substantially flat portion of the elastic member 13. Thereby, at the position where the fusion portion 15a, 15b is formed, the surface of the second sheet 12 facing the elastic member 13 is along the above-mentioned substantially flat portion of the elastic member 13. Therefore, the stretchable sheet of this embodiment is located between the pair of first fusion portions 15a, 15b, the surface on the second sheet side is substantially flat, and on the other hand, the surface on the first sheet side faces the outer side of the thickness direction Z Bulge. That is, in this embodiment, the porosity change area 20 has a shape following the shape of the elastic member 13. Specifically, the porosity change region 20 is in close contact with the surface of the elastic member 13 that faces the porosity change region 20, and has a shape that follows the shape of the surface.

In the porosity change region 20, a part of the constituent fibers, particularly a part of the constituent fibers in the side portions S and S loses the fiber shape and becomes a melted and solidified state, and the remaining portion of the constituent fibers maintains the fiber shape. That is, the porosity change region 20 is a region where fibers having a melt-solidified portion and fibers without a melt-solidified portion are mixed. Compared with the central part M, the two side parts S and S of the porosity change area 20 have more fibers having melted and solidified parts, but the central part M may also contain fibers having melted and solidified parts. In addition, the elastic member overlapping region 21 may also contain fibers having melted and solidified portions. The amount of fibers having melted and solidified parts can be measured by observation with a scanning electron microscope. The amount of fiber or the state of melting and solidification of the fiber (the state of constituting the fiber) can be confirmed by the following method.

The stretchable sheet of the present invention exhibits stretchability by being provided with an elastic member. Therefore, it can be preferably used to form an outer body of the outer surface of an absorbent article, which fits well to the wearer's skin . Furthermore, when the stretchable sheet of the present invention is used for an exterior body, there is an advantage that even if the exterior body is stretched in a direction (Y direction) orthogonal to the extending direction of the elastic member 13 and fixed to The elastic member 13 between the first sheet 11 and the second sheet 12 is also not easy to fall off, and the conformability of the elastic member 13 can be maintained. In view of this advantage, a diaper 1 having waist openings WO and leg openings LO as shown in FIG. 4 will be described as an example. When the diaper 1 is worn, the wearer's legs are passed through the leg openings LO, and then the diaper 1 is pulled up to the wearer's waist side, that is, the outer body is usually stretched to the waist side. At this time, at the position where the first fusion portion 15a, 15b of the stretchable sheet 10 is formed, a tensile load is applied to one side of the Y direction as shown in FIG. The interface between the first fusion portions 15a, 15b is not clear, so for the Y-direction stretching, the void ratio change region 20 and the first fusion portions 15a, 15b are not easily broken. "The interface between the porosity change area 20 and the first fusion portion 15a, 15b is not clear" means that the portion of the side portion S that has lost the fiber shape or the melted and solidified portion of the fiber continues to be closer to Y than the side edge of the elastic member 13 A state where the boundary between the side portion S and the first fusion portion 15a becomes unclear on the outer side of the direction. This state is due to the fact that the porosity of the two sides S and S of the porosity change region 20 is lower than that of the central part M, that is, the amount of fibers with melted and solidified parts in the two sides S and S is more than that of the central part M. cause. On the other hand, the central portion M of the porosity change region 20 has more fibers maintaining the fiber form than the side portions S and S. Therefore, the tensile load in the Y direction can be moved in this direction. Stretch up. By having the above structure, even if the stretchable sheet 10 receives a tensile load on one side of the Y direction, the second sheet is not easily broken between the first fusion portions 15a, 15b (see FIG. 5), so it can be effectively The elastic member 13 is prevented from falling off between the first sheet 11 and the second sheet, and the good conformability of the elastic member 13 can be maintained. On the other hand, as shown in FIG. 6, in the previous stretchable sheet in which all the constituent fibers between the pair of first fusion portions 15a, 15b in the second sheet maintain the fiber form, the second sheet in the second sheet 1 The interface between the fusion portion 15a, 15b and the region overlapping with the elastic member 13 is clear. Therefore, if a tensile load is applied to one side in the Y direction, the second sheet is likely to break at the interface. If the above-mentioned fracture occurs, the elastic member will fall off between the first sheet and the second sheet, and it will be difficult to maintain the conformability of the elastic member.

Moreover, in the stretchable sheet of the present invention, as described above, when the stretchable sheet is viewed along the Y-direction cross section at the formation positions of the first fusion portions 15a and 15b, the first sheet 11 and the elastic member The length of the contact 13 is longer than the length of the contact of the second sheet 12 and the elastic member 13. Therefore, when the stretchable sheet of the present invention is used, for example, as an outer body to form an outer surface of an absorbent article, and the stretchable sheet is arranged so that the second sheet 12 faces the wearer's skin, it can be The porosity change region 20 formed in the second sheet 12 reduces the extent that the elastic member 13 presses the skin of the wearer. Therefore, there is an advantage that it is not easy to produce uncomfortable feeling in the state of wearing the absorbent article. Conversely, when the stretchable sheet is arranged on the absorbent article with the second sheet 12 facing the clothing side, most of the cross-section of the elastic member 13 exists on the wearer's skin side, so there is The stretchable sheet has the advantage of softly contacting the wearer's skin.

The measurement of porosity is carried out by the following method. [Method for measuring porosity] After freezing the stretchable sheet with liquid nitrogen or the like, cut out the elastic member fixed by a pair of first fusion parts from the center of the stretched direction of the elastic member in the stretchable sheet The part. At this time, it was cut in the direction orthogonal to the extension direction of the elastic member, and this was used as a sample. As mentioned above, the elastic member is fixed only by friction with the first sheet and the second sheet, and the elastic member does not fuse with the first sheet and the second sheet. Therefore, when the sample is cut out, there is At this time, the elastic member fell off the sample. When the elastic member remains in the sample, the elastic member is removed from the sample. Then, a scanning electron microscope (for example, JEOL Ltd., JSM-IT100) was used to magnify and observe the cross-section of the sample. The magnification during observation is set to a magnification of 100 to 200 times, so that the first sheet and the second sheet can be observed in the thickness direction of the sample and the two between the pair of first fused parts can be observed in the extension direction of the elastic member. Ends. In this observation field of view, the longer-length sheet in contact with the elastic member is set as the first sheet, and the shorter sheet is set as the second sheet to distinguish, and the second sheet is measured by image analysis. The area occupied by the fibers in the sheet. Specifically, for the image of the observation field, image processing software such as ImageJ is used to set a threshold value for the brightness boundary between the fiber and the part where the fiber is not present, and the brightness is binarized. Generally, when white and black are binarized, the fiber becomes white, and the part where there is no fiber becomes black. Therefore, the white part can be recognized as a fiber and the black part can be recognized as a void. Moreover, when observing only the side surface without observing the cross-section of the fiber, all parts other than the cross-section are recognized as voids. Then, in the observation field of view, the outer edge of the region overlapping the elastic member in the thickness direction of the second sheet is drawn along the outline of the white portion described above, and the outline of the porosity change region is specified. Then, the area surrounded by the specified contour is divided into three equal parts in the Y direction, the center of the three areas is referred to as the central portion, and both sides of the central portion are referred to as side portions. Then, using the above-mentioned image processing software, the area of the central part (A ₁ ) is measured, and the area of the part recognized as a void in the area of the central part is measured, and this is set as the void area (A ₂ ). Then, according to the following formula [1], the porosity (GR) at the center of the porosity change region is calculated. The porosity of the side part is also calculated by the same method as the porosity of the center part. GR(%)=(A ₂ /A ₁ )×100...Equation [1] GR: Porosity A ₁ : Area of the central part A ₂ : Area of the void in the central part It is performed at any 3 locations of the part, and the average value is set as the porosity of the porosity change area.

The porosity of the entire porosity change region and other regions can also be measured in the same manner as the above method. The porosity of the entire porosity change area is performed after identifying the outline of the porosity change area from the first sheet in the image of the observation field. The porosity of the other regions is performed by magnifying observation of any part in the region other than the region overlapping with the elastic member 13 in the thickness direction Z in the second sheet material and the region other than the fusion part.

The state of the constituent fibers in the porosity change area 20 is to observe the sample by the same method as the measurement method of the porosity described above, and confirm whether the second sheet in the area overlapping the elastic member meets the following conditions (1)~ (4) All of. Condition (1): All fibers are not resinized in the area overlapping with the elastic member. Condition (2): At least one fiber has a fusion-solidified portion formed by resinization, and other fibers adjacent to the fiber are integrated through the fusion-solidified portion. Condition (3): There are gaps (voids) between fibers or between the melted and solidified part of the fibers and other fibers. The gap is set in the range of 1 μm to 50 μm. Condition (4): At least one fiber does not have a fusion-solidified portion and maintains the fiber form. In the porosity change region 20, the side portions S and S have a lower porosity than the center portion M, and therefore, there is a tendency that the above condition (2) is satisfied compared to the center portion M.

The amount of fibers with melted and solidified parts is the total number of fibers with melted and solidified parts observed by the same method as the above-mentioned method for measuring the porosity. The area of the melted and solidified portion existing in the contours of the porosity change area 20, the central portion M or the side portion S is larger than the cross-sectional area of the fiber observed in other areas. When the contour of the fiber is not clear, measure _{The area (B 2} ) of the melted and solidified part and the average cross-sectional area per fiber (B ₁ ) observed in other regions are calculated according to the following formula [2] to find the number of fibers in each melted and solidified part (B), increase it to the total number of fibers with melted and solidified parts. The average cross-sectional area (B ₁ ) of each fiber is set to the average value of 3 fibers arbitrarily selected in other regions. B=B ₂ /B ₁ …〔2〕 B: The number of fibers in each fusion and solidification part B ₁ : The average cross-sectional area of each fiber B ₂ : The area of the fusion and solidification part contains fibers with a fusion and solidification part The amount is measured at any three locations where a pair of first fusion portions are formed in the stretchable sheet, and is set as the average value of the same.

In the above-mentioned method for measuring the porosity, the cut surface of the sample is observed in the state of a microscope image as shown in FIG. 8, for example. The cavity in the center of the microscope image shown in FIG. 8 is the part where the elastic member is arranged, and the film-like part at the position interposed between the cavity is the first fusion part. In the microscope image shown in FIG. 8, the void ratio change area is indicated by a frame line. The melted and solidified part of the fiber in the porosity change area is shown in FIG. In addition, in FIG. 8, the portion opposed to the porosity change area with the cavity interposed therebetween is the area where the elastic member overlaps. In this figure, the overlapping region of the elastic member does not have a melted and solidified portion of the fibers, so the fibers are dispersed and not integrated.

As described below, from the viewpoint of forming a fold structure on each surface of the stretchable sheet 10 to improve the touch and air permeability of the skin, the bonding strength of the second fusion portion 16a, 16b is preferably smaller than that of the first fusion portion 15a , 15b. With this configuration, it is possible to suppress the elongation of the stretchable sheet 10 in this direction due to the stretching in the Y direction, and it is possible to suppress the concentration of the tensile load between the pair of first fusion portions 15a and 15b. From the viewpoint of making the above effects more reliable, the bonding strength of the second fusion portion 16a, 16b is preferably 50% or more and 95% or less, and more preferably, the bonding strength of the first fusion portion 15a, 15b It is 60% or more and 90% or less, more preferably 70% or more and 80% or less. The bonding strength of the fusion part is measured by the following method.

＜Measuring method of bonding strength＞ From the stretchable sheet, a measuring piece measuring 20 mm×100 mm is cut out to include the first fusion part or the second fusion part. Then, the fusion part other than the fusion part of the measurement object in the measurement piece is peeled off. Then, the 20 mm side of the first sheet of the measurement piece was fixed to one of the chucks of the TENSILON universal testing device RTG1310 (A&D Co., Ltd.), the second piece of the measurement piece was fixed to the other chuck, and the measurement piece Place between these chucks. The distance between the chucks is set to 20 mm. Then, the chuck was moved along the 180° direction at a speed of 300 mm/min to separate the first sheet from the second sheet. Determine the maximum force observed at this time. The above measurement was repeated 5 times, and the average value thereof was taken as the peel strength.

From the viewpoint of making the bonding strength of the second fusion portions 16a, 16b smaller than the bonding strength of the first fusion portions 15a, 15b, the dimensions of the first fusion portions 15a, 15b and the second fusion portions 16a, 16b are preferably as follows Within range. The length L4 of the second fusion portion 16a, 16b in the Y direction (see FIG. 1) is relative to the length L7 between the outer ends of the first fusion portion 15a, 15b adjacent in the Y direction (see FIG. 1). In other words, it is preferably 2% or more, more preferably 10% or more, more preferably 90% or less, more preferably 80% or less, more preferably 2% or more and 90% or less, more preferably 10% or more Below 80%. The length L7 between the outer ends of the first fusion portions 15a, 15b adjacent in the Y direction is the length of the elastic member 13 in the Y direction and a pair of the first fusion portions 15a, 15b located on both sides of the elastic member 13 The total length of each in the Y direction. The distance P1 between the first fusion portions 15a, 15b adjacent in the X direction (see FIG. 1) is preferably relative to the length L5 (see FIG. 1) of the first fusion portions 15a, 15b along the X direction 30% or more, more preferably 500% or more, more preferably 6000% or less, more preferably 3000% or less, more preferably 30% or more and 6000% or less, more preferably 500% or more and 3000% or less. The distance P1 between the first fusion portions 15a, 15b adjacent in the X direction is synonymous with the distance between the first fusion portion pairs 15 adjacent in the X direction. The distance P1 between the first fusion portions 15a, 15b adjacent in the X direction is the sum of the length between the first fusion portions 15a, 15b adjacent in the X direction and the length of the first fusion portions 15a, 15b in the X direction .

The length L4 of the second fusion portion 16a, 16b along the Y direction (refer to FIG. 1) is preferably 0.2 mm or more, more preferably 0.4 mm or more, more preferably 5.0 mm or less, more preferably 3.0 mm or less, Furthermore, it is preferably 0.2 mm or more and 5.0 mm or less, and more preferably 0.4 mm or more and 3.0 mm or less. The length L5 of the first fusion portion 15a, 15b along the X direction (see FIG. 1) is preferably 0.1 mm or more, more preferably 0.4 mm or more, more preferably 3.0 mm or less, and more preferably 1.0 mm or less, Moreover, it is preferably 0.1 mm or more and 3.0 mm or less, and more preferably 0.4 mm or more and 1.0 mm or less. The length of the second fusion portion 16a, 16b along the X direction is also preferably within the same range as the length L5 of the first fusion portion 15a, 15b along the X direction. The distance P1 between the first fusion portions 15a, 15b adjacent in the X direction (refer to Fig. 1) is preferably 1.0 mm or more, more preferably 2.0 mm or more, more preferably 6.0 mm or less, and more preferably 4.0 mm Hereinafter, it is more preferably 1.0 mm or more and 6.0 mm or less, and more preferably 2.0 mm or more and 4.0 mm or less. The length L7 (refer to Fig. 1) between the outer ends of the first fusion portions 15a, 15b adjacent in the Y direction is preferably 1.0 mm or more, more preferably 1.4 mm or more, and more preferably 10.0 mm or less, It is more preferably 5.0 mm or less, more preferably 1.0 mm or more and 10.0 mm or less, and more preferably 1.4 mm or more and 5.0 mm or less.

From the same viewpoint as the above, the distance P2 (refer to FIG. 1) between adjacent elastic members 13 in the Y direction is preferably 0.5 mm or more, more preferably 3.0 mm or more, and more preferably 10.0 mm or less, It is more preferably 7.0 mm or less, more preferably 0.5 mm or more and 10.0 mm or less, and more preferably 3.0 mm or more and 7.0 mm or less. The distance P2 between the elastic members 13 adjacent in the Y direction (refer to FIG. 1) is the sum of the length Le between the elastic members 13 adjacent in the Y direction (refer to FIG. 1) and the length of the elastic members 13 in the Y direction.

The relaxed state of the stretchable sheet 10 is shown in FIG. 7. As described above, the first sheet 11 and the second sheet 12 are joined by a plurality of fusion portions arranged along the Y direction. In the relaxed state of the stretchable sheet 10, the elastic member 13 shown in FIG. 1 shrinks, and the width of the shrinkable sheet 10 in the X direction becomes narrow. The first sheet 11 lost its place due to the narrowing of the width is a plurality of first fusion portion pairs 15 (first fusion portion 15a, 15b) or second fusion portion pair 16 (second fusion portion pair 16) intermittently arranged in the X direction. The fusion part 16a, 16b) is the starting point of bending, and protrudes away from the elastic member 13 as shown in FIG. 7. That is, in the stretchable sheet 10, the convex part 17 which protrudes in the direction away from the elastic member 13 along the thickness direction Z of the stretchable sheet 10 is formed in the 1st sheet 11. As shown in FIG.

In this embodiment, the first sheet 11 and the second sheet 12 are intermittently arranged in a plurality of first fusion portion pairs 15 (first fusion portion 15a, 15b) or second fusion portion pairs 16 in the X direction (The second fusion portion 16a, 16b) is the starting point of bending, and protrudes so as to be separated from each other in the thickness direction as shown in FIG. 7. That is, in the stretchable sheet 10, the convex part 17 which protrudes so that it may mutually separate in the thickness direction Z is formed in the 1st sheet 11 and the 2nd sheet 12, respectively. The above-mentioned convex portion 17 is a part of the stretchable sheet 10 that forms the following fold structure (fold), and follows the elasticity at the position overlapping the elastic member 13 with the first sheet 11 and the second sheet 12 The part where the shape of the member 13 is partially different. In addition, on both sides of the stretchable sheet 10 (the surface on the side of the first sheet 11 and the surface on the side of the second sheet 12) is formed a plurality of convex portions 17 and a concave portion located between the plurality of convex portions 17 The fold structure. That is, a plurality of folds are formed by the convex portion 17. The plurality of convex portions 17 and the plurality of concave portions described above each extend continuously in the Y direction. The inside of the convex part 17 is hollow. The stretchable sheet 10 in the state shown in FIG. 7 exhibits a soft texture and an excellent appearance due to the above-mentioned fold structure.

When the stretchable sheet 10 having the above-mentioned fold structure is used, for example, as a constituent member of an absorbent article such as a disposable diaper, especially a member that can contact the wearer's skin, the effect of the convex portion 17 is mainly used. The contact area between the sheet 10 and the skin becomes smaller, and the ratio of the sweat diffusion area to the contact area becomes larger. Therefore, the sweat transpiration effect is improved, and the contact area between the sheet 10 and the skin wetted by sweat becomes larger. It is reduced, so the wearing feeling of the absorbent article is improved. In addition, the stretchable sheet 10 having the above-mentioned fold structure exhibits a soft texture and an excellent appearance due to the fold structure. Therefore, an absorbent article including the sheet 10 has a good appearance.

From the viewpoint of making the formation of the above-mentioned fold structure easier, when the interval between two elastic members 13 adjacent in the Y direction is set to Le (refer to FIG. 1), the second fusions adjacent in the Y direction are fused The ratio of the length L16 between the outer ends of the portions 16a and 16b (see FIG. 1) to the interval Le, that is, the value of L16/Le, is preferably 0.25 or more, more preferably 0.50 or more, and more preferably 0.70 or more. In terms of ensuring the bonding strength, the closer the value of L16/Le is to 1, the better. The length L16 between the outer ends of the second fusion portions 16a, 16b adjacent in the Y direction is between the respective lengths of the second fusion portions 16a, 16b adjacent in the Y direction and the second fusion portions 16a, 16b The total length of.

From the viewpoint of making the above-mentioned sweat transpiration effect more surely exhibited, the dimensions and the like of each part of the stretchable sheet 10 are preferably set as follows. The interval Le between two adjacent elastic members 13 along the Y direction is preferably 1 mm or more. In addition, the value of Le is preferably 10 mm or less, more preferably 8 mm or less, and still more preferably 6 mm or less. The value of Le is preferably 1 mm or more and 10 mm or less, more preferably 1 mm or more and 8 mm or less, and still more preferably 1 mm or more and 6 mm or less. The interval P1 (refer to FIG. 1) between the two adjacent fusion portion pairs 15, 15 (16, 16) along the X direction is preferably 6 mm or less, more preferably 5 mm or less, and still more preferably 3 mm or less. The lower limit of P1 is not particularly limited, but the lower limit is as small as possible, and the diffusion area of sweat increases, which is preferable. The length (width) of each of the first fusion portion pair 15 and the second fusion portion pair 16 in the X direction is preferably 3 mm or less, more preferably 2 mm or less, and still more preferably 1 mm or less. The lower limit of the width is not particularly limited, and the smaller the better.

The material constituting the stretchable sheet 10 will be described in detail. As the first sheet 11 and the second sheet 12, for example, hot-air non-woven fabric, hot-rolled non-woven fabric, spunlace non-woven fabric, spunbonded non-woven fabric, melt-blown non-woven fabric and other non-woven fabrics obtained by various manufacturing methods can be used, and the two kinds of The laminated body formed by the integration of the above laminated layers, etc. From the viewpoint of forming beautiful appearance, better tactile and soft folds, the fiber sheet used as two sheets or one sheet is preferably hot-air non-woven fabric, hot-rolled non-woven fabric, spunlace non-woven fabric, spunbonded non-woven fabric, melt Spray non-woven fabrics, etc. From the viewpoint of further improving the bonding strength of the first fusion portion 15a, 15b and the second fusion portion 16a, 16b to further suppress the release of the fixing of the elastic member that occurs when the diaper is worn, the first sheet and the second sheet The material is preferably a laminated non-woven fabric with a spunbonded non-woven fabric layer. As such a laminated nonwoven fabric, a laminated nonwoven fabric of a spunbond nonwoven fabric layer (S) and a meltblown nonwoven fabric layer (M), namely SM (Spunbond Meltblown, spunbond-meltblown) nonwoven fabric or SMS (Spunbond Meltblown Spunbond, spunbond-melt) Spray-spunbond) non-woven fabrics, etc.

As described above, as the first sheet 11 and the second sheet 12, it is preferable to use a non-woven fabric. The basis weight of the non-woven fabric is preferably 5 g/m ² or more and 50 g/m ² or less, particularly ^{preferably 8 g/m 2} or more and 30 g/m ² or less. The buckling strength of the non-woven fabric of this basis weight is preferably 50 cN or less in the direction orthogonal to the machine travel direction (CD), particularly preferably 30 cN or less, and preferably 70 cN in the machine travel direction (MD) Below, it is particularly preferably 50 cN or less. By using a soft sheet, the formation of the above-mentioned folds can be improved. The buckling strength is measured by the following method.

Buckling strength test method: Use a rectangular test piece that is 150 mm in the machine direction (MD) and 30 mm in the direction orthogonal to the machine direction (CD). The test piece was cut out of 5 pieces from the measurement object sheet. Using this test piece, a cylinder with a diameter of 45 mm was made, and the upper and lower ends of the overlapping part were nailed with a stapler or the like, and this was used as a measurement sample. For the measurement sample, the compression test mode of the TENSILON universal testing device is used to measure the maximum strength when compressed to 20 mm under the measurement conditions of a compression speed of 10 mm/min and a measurement distance of 20 mm. The measurement environment is set to 20°C and 65%RH. Under the above-mentioned measurement, the average value of the above-mentioned maximum strength of each measurement sample was obtained, and this was set as the buckling strength in the above-mentioned orthogonal direction (CD). The buckling strength in the machine direction (MD) is a rectangular test piece that is 150 mm in the direction orthogonal to the machine direction (CD) and 30 mm in the machine direction (MD). Except for this aspect, Measured by the same method as above.

The first sheet 11 and the second sheet 12 are not limited to two separate sheets, and one sheet may be bent to form two opposing faces, and the part that constitutes one face is made into one sheet. The part constituting the other side is set as another sheet. When the first sheet 11 and the second sheet 12 are composed of one sheet, the one sheet is preferably a hydrophilic fiber sheet.

As the forming material of the elastic member 13, various known elastic materials used in absorbent articles such as disposable diapers and menstrual napkins can be used without particular limitation. Examples of materials include synthetic rubbers such as styrene-butadiene, butadiene, isoprene, and neoprene, natural rubber, EVA (ethylene vinyl acetate), stretchable polyolefins, and polyolefins. As the form of the urethane, etc., a linear or string-shaped (flat tape, etc.) with a rectangular, square, circular, polygonal cross section, or a multifilament-shaped thread can be used.

Next, a preferred method of manufacturing the stretchable sheet 10 shown in FIG. 1 will be described with reference to FIG. 9. In this figure, a manufacturing apparatus 100 which can be preferably used for manufacturing the stretchable sheet 10 is shown. The manufacturing apparatus 100 includes an ultrasonic processing unit 101. The ultrasonic processing unit 101 includes an ultrasonic processor 30 having an ultrasonic vibration welding head 31 and a receiving roller 40 arranged at a position facing the vibration application surface 31t of the front end of the welding head 31. The ultrasonic processing unit 101 sandwiches the laminated body 14 of the first sheet 11, the second sheet 12, and the elastic member 13 as the processing target between the vibration applying surface 31t of the welding head 31 and the peripheral surface 40t of the receiving roller 40 ( Specifically, ultrasonic vibration is applied between the protruding portion pairs 41, 42 (the front end surfaces) described below, and thereby the first fusion portions 15a, 15b (first fusion portion pair 15) as fusion portions are formed in the laminated body 14. ) And the second fusion portion 16a, 16b (the second fusion portion pair 16) to join the two sheets 11, 12.

The direction of travel (machine travel direction, hereinafter also referred to as "MD") when manufacturing the stretchable sheet 10 is the same as the elasticity in the following laminated body 14 as the product of the stretch sheet 10 or the intermediate for its manufacture The extending direction (X direction) of the member 13 is the same, and the direction orthogonal to the MD (hereinafter also referred to as "CD") is the width direction (Y direction) of the elastic member 13 in the stretchable sheet 10 or laminate 14 ) Consistent. In addition, the rotation axis of the receiving roller 40 is parallel to CD and orthogonal to MD.

The ultrasonic processor 30 includes an ultrasonic oscillator (not shown), a converter (not shown), a booster (not shown), and a welding head 31, and these are connected to each other. The ultrasonic oscillator is electrically connected to the transducer, and a high-voltage electrical signal with a wavelength of about 15-50 kHz generated by the ultrasonic oscillator is input to the transducer. The transducer has a built-in piezoelectric element such as a piezoelectric element, and converts the electrical signal input from the ultrasonic oscillator into mechanical vibration by the piezoelectric element. The horn system adjusts the amplitude of the mechanical vibration emitted from the transducer, preferably amplifies and transmits it to the welding head 31. The welding head 31 is formed of metal such as aluminum alloy or titanium alloy, and is designed to correctly resonate in the frequency band used. The vibration applying surface 31t at the front end of the horn 31 abuts on one surface of the object to be processed (the second sheet 12 in this embodiment). The ultrasonic vibration transmitted from the horn to the welding head 31 is also amplified or attenuated inside the welding head 31 and applied to the processing object. As the ultrasonic processor 30, commercially available welding heads, transducers, horns, and ultrasonic oscillators can be used in combination.

The ultrasonic processor 30 is fixed to a movable table (not shown). By making the position of the movable table advance and retreat in a direction approaching the peripheral surface 40t of the receiving roller 40, the vibration application surface 31t of the welding head 31 and The gap between the peripheral surface 40t of the receiving roller 40 (specifically, the front end surface of the convex portion pair 41, 42 described below) and the pressing force against the object to be processed.

The ultrasonic processing part 101 is equipped with a heating mechanism which heats the processing target object to which ultrasonic vibration is to be applied. In this embodiment, the receiving roller 40 is designed to be able to adjust the temperature of the receiving roller 40, and thereby, the first sheet 11 and the second sheet 12 that are in contact with the receiving roller 40 can be heated. That is, by winding around the receiving roller 40, the first sheet 11 and the second sheet 12 can be heated. The receiving roller 40 can adjust the temperature of the receiving roller 40 by, for example, a heater for heating the receiving roller 40 and a temperature sensor for measuring the temperature of the receiving roller 40 are provided inside the rotating shaft side. The horn 31 described below is pressed against the second sheet 12 to directly apply ultrasonic vibration to the second sheet 12.

The receiving roller 40 has unevenness|corrugation on the peripheral surface 40t which winds up a processing target object. Specifically, as shown in FIG. 10, the peripheral surface 40t of the receiving roller 40 is provided with a plurality of first convex portion pairs 41 for forming the first fusion portion pair 15 and pluralities for forming the second fusion portion pair 16 respectively. A second convex pair 42. The first protrusion pair 41 and the second protrusion pair 42 form protrusions protruding toward the welding head 31 on the peripheral surface of the receiving roller. That is, the first convex portion pair 41 and the second convex portion pair 42 are located on the side close to the horn 31. The two convex portion pairs 41 and 42 are respectively intermittently arranged in the circumferential direction (rotation direction R) of the receiving roller 40 to form a row. That is, in the receiving roller 40, the first protrusion pair 41 is located on the same line in the rotation direction R, and the second protrusion pair 42 is located on the same line in the rotation direction R. In the receiving roller 40 in this embodiment, the first convex portion pair 41 and the second convex portion pair 42 are alternately arranged in the width direction. The row of the first convex portion pair 41 and the row of the second convex portion pair 42 described above are alternately arranged in the rotation axis direction (CD) of the receiving roller 40. The plurality of first convex portion pairs 41 respectively have a pair of first convex portions 41a, 41b arranged at intervals on the CD, and a first concave portion 43 located between the two convex portions 41a, 41b. The plurality of second convex portion pairs 42 respectively have a pair of second convex portions 42a and 42b arranged at intervals on the CD, and a second concave portion 44 located between the two convex portions 42a and 42b. The first concave portion 43 of the first convex portion pair 41 has a shorter width (the length of CD) than the second concave portion 44 of the second convex portion pair 42. In addition, the first recessed portion 43 protrudes outward in the radial direction of the receiving roller 40 compared to the second recessed portion 44, that is, is farther from the center of rotation of the receiving roller 40 (refer to FIG. 12). The elastic member 13 is introduced into the first concave portion 43 of the first convex portion pair 41. The elastic member 13 is not introduced into the second concave portion 44 of the second pair of convex portions 42. In addition, in FIG. 10, the description of the first sheet 11 is omitted for description, and the elastic member 13 is directly introduced into the first recess 43, and the elastic member 13 is in contact with the peripheral surface 40t of the receiving roller 40. In the case of the flexible sheet 10, as shown in FIG. 11, the first sheet 11 is introduced into the first recess 43 before the elastic member 13, and therefore, the elastic member 13 and the receiving roller 40 are not in contact with each other.

In FIG. 12, the main part of the ultrasonic processing unit 101 in FIG. 9 is enlarged and shown. The Y direction shown in FIG. 12 is the width direction (axial direction) of the receiving roller 40, and this direction is consistent with the Y direction in the stretchable sheet 10 to be manufactured. As shown in the figure, on the peripheral surface of the receiving roller 40 in the ultrasonic treatment section 101, a first convex portion pair 41 and a second convex portion pair 42 are arranged along the axial direction. On the other hand, in the welding head 31, the surface which has the part contacting the 1st convex part pair 41 and the 2nd convex part pair 42 becomes a flat surface without unevenness|corrugation.

As shown in FIG. 12 and FIG. 13, in the 1st convex part pair 41, the 1st recessed part 43 is provided in the Y direction, ie, the approximate center part of a roll width direction. The first recess 43 has a substantially rectangular shape when viewed in a cross section along the width direction (CD) of the receiving roller 40. The first recess 43 has a volume for accommodating at least a part of the elastic member 13 in an extended state. In other words, the first concave portion 43 has a volume such that the elastic member 13 can partially protrude from the upper surface of the first convex portion pair 41 in a state where the first concave portion 43 accommodates the elastic member 13. The length of the first concave portion 43 along the Y direction (CD), that is, the opening width of the first convex portion pair 41 along the CD (the length indicated by the symbol c in FIG. 13) is roughly equivalent to the target stretchable sheet The first fusion zone interval D in 10 (refer to Fig. 2).

The manufacturing method of the stretchable sheet 10 using the manufacturing apparatus 100 configured as described above has a fusion part forming step in which the elastic member 13 is arranged between the two sheets 11 and 12 in a state of being stretched in one direction. , The two sheets 11, 12 are joined to each other at multiple locations on both sides of the elastic member 13 in the Y direction (CD) across the elastic member 13 in its stretched state to form a plurality of fused portion pairs 15, 16 . In addition, the method of manufacturing the stretchable sheet 10 using the manufacturing apparatus 100 has an elastic member relaxation step, which releases the stretched state of the elastic member 13 and relaxes the elastic member 13 by the elasticity accompanying the relaxation. The increase in the width direction length (diameter) of the member 13 increases the adhesion between the part of the elastic member 13 sandwiched between the pair of fusion portions 15, 16 and the pair of fusion portions 15, 16 than before the slack, thereby, The fusion portion pair 15 and 16 are used to clamp the elastic member 13 in a state of being stretched at a specific elongation rate.

In the fusion portion forming step, first, the first sheet 11, the second sheet 12, and a plurality of elastic members 13 arranged in an extended state between the two sheets 11, 12 and extending in one direction are formed to have the等的层体14。 Such a laminate 14. In this embodiment, the layered body 14 is formed by the following method. As shown in FIG. 9, the long strip-shaped first sheet 11 is continuously rolled out from the original sheet 11a and introduced onto the peripheral surface 40t of the receiving roller 40, and the long strips are respectively removed from the plurality of winding bodies 13a. The elastic member 13 is continuously rolled out, and is arrange|positioned on the 1st sheet|seat 11 on this peripheral surface part 40t. At the stage where the elastic members 13 have been arranged on the first sheet 11 (for example, the position indicated by the symbol P11 in FIG. 9), each elastic member 13 is in an extended state. Also, at this stage, as shown in FIG. 11, each elastic member 13 is transported in a state where a part of the elastic member 13 is accommodated in the first concave portion 43 of the first convex portion pair 41 provided on the peripheral surface 40t of the receiving roller 40 . In the first recess 43, the first sheet 11 is housed before the elastic member 13, and the elastic member 13 and the receiving roller 40 are not in contact with each other.

When a part of the first recess 43 is accommodated in an extended state, the extent of extension of the elastic member 13 is greater than that of the elastic member 13 in the maximum extension state of the stretchable sheet 10, and the diameter of the elastic member 13 is larger than that of the first The opening width of the recess 43 along the Y direction is small. Thereby, in the obtained stretchable sheet 10, the pinching force of a pair of 1st fusion part 15a, 15b can be increased, and the frictional force of the elastic member 13 and the 1st sheet material 11 and the 2nd sheet material can be fully ensured.

Then, as shown in FIG. 9, the long strip-shaped second sheet 12 is continuously unrolled from the original sheet 12 a and is introduced onto the peripheral surface 40 t of the receiving roller 40. Thereby, the elongated laminated body 14 (the manufacturing intermediate body of the stretchable sheet 10) in which the elastic member 13 in the extended state is arrange|positioned between the 1st sheet material 11 and the 2nd sheet material 12 is formed in the peripheral surface part 40t. The first sheet 11 and the second sheet 12 in the long laminate 14 are preheated by being wound around the receiving roll 40 as described above. In addition, ultrasonic vibration is applied to the laminate 14 by the horn 31 (refer to FIGS. 12 and 13). Specifically, the layered body 14 is transported to the pressing position (ultrasonic processing position) of the welding head 31 on the object to be processed indicated by the symbol P12 in FIG. 9 by the receiving roller 40 rotating in the R direction, and is transported there In the middle, it is preheated by the above-mentioned heating mechanism etc. built in the receiving roller 40.

The ultrasonic processor 30 fuses the first sheet 11 and the second sheet 12 in the laminate 14 at a plurality of positions spaced apart along the Y direction at positions on both sides of the elastic member 13. Thereby, one pair of the first fusion portion 15a, 15b and the second fusion portion 16a, 16b are formed. Specifically, as shown in FIGS. 9 and 12, at the ultrasonic treatment position P12, the laminate 14 is sandwiched between the front end surfaces of the protruding pairs 41, 42 of the receiving roller 40 and the vibration application surface 31t of the welding head 31. Pressure is applied, and ultrasonic vibration is applied to the two sheets 11 and 12 (the above-mentioned fusion portion forming step). As shown in FIG. 12, the first convex portion pair 41 and the second convex portion pair 42 on the peripheral surface of the receiving roller 40 protrude more than the other portions, and are located on the side closer to the welding head 31. The portion overlapping with the front end surfaces of the first convex portion 41a, 41b and the second convex portion 42a, 42b forming the first convex portion pair 41 and the second convex portion pair 42 generates heat, and the first sheet 11 and/or the second sheet The material 12 is melted and solidified again, whereby the first sheet 11 and the second sheet 12 located on the first pair of convex portions 41 and the second pair of convex portions 42 are fused to form a first fusion joining these sheets Parts 15a, 15b and second fusion parts 16a, 16b. That is, the first fused portion pair 15 is formed in the layered body 14 in contact with the first convex portion pair 41, and the second fused portion pair 16 is formed in the layered body 14 in contact with the second convex portion pair 42 section. At this time, the laminate 14 is pressurized by the welding head 31 to be in a state in which a substantially flat portion is formed on the second sheet 12 side of the elastic member 13, and the second sheet 12 is in close contact with the elastic member 13 and extends along Follow the roughly flat part. That is, between the pair of first fusion portions 15a and 15b, the shape of the elastic member 13 on the second sheet 12 side and the shape of the second sheet 12 are maintained substantially flat. In addition, by the above-mentioned fusion, a part of the constituent fibers between one of the second sheet 12 and the first fusion part 15a, 15b is partially melted and solidified due to a decrease in temperature. In this process, a part of the fibers constituting the pair of the first fusion portion 15a, 15b of the second sheet 12 is melted to form the porosity change region 20, and the first fusion portion 15a, 15a of the first sheet 11 is An elastic member overlapping area 21 is formed between 15b. When the first fusion portion pair 15 is formed, the elastic member 13 is partially housed in the first recess 43, and the elastic member 13 is not fused with the first sheet 11 and the second sheet 12, and maintains a non-joined state. In this way, by the fusion by the ultrasonic processor 30, the stretchable sheet 10 of the form shown in FIG. 1 can be obtained.

In the obtained stretchable sheet 10, when the stretched state of the elastic member 13 is released, the length of the elastic member 13 becomes shorter and the diameter thereof becomes larger. In this embodiment, as shown in FIG. 9, the long strip-shaped laminate 14 in which the first fusion portion pair 15 and the second fusion portion pair 16 are formed is cut into pieces by the cutting portion 22 provided in the manufacturing apparatus 100 Specific product unit length (above-mentioned elastic member relaxation step). Thereby, the stretched state of the elastic member 13 is released, and a plurality of single stretchable sheets 10 can be obtained. As shown in Fig. 2, the elastic member 13 with a larger diameter after the extended state is released becomes the distance between the two first fusion portions 15a, 15b, that is, the first fusion portion interval D or more, and preferably exceeds the first fusion portion interval D . Thereby, the elastic member 13 is pinched by the two first fusion portions 15a and 15b, and is fixed only by the friction of the first sheet 11 and the second sheet 12.

The fixing of the elastic member 13 in the stretchable sheet 10 will be described in detail. The state of the elastic member 13 before and after the above-mentioned elastic member relaxation step is shown in FIG. 14. Fig. 14(a) shows the state before the elastic member relaxation step is performed, that is, before the elastic member 13 (layered body 14) is cut (the state of the elastic member 13 in the elongated belt-shaped layered body 14), Fig. 14(b) ) Represents the state after the elastic member relaxation step is performed, that is, the elastic member 13 (layered body 14) is cut to release the stretched state of the elastic member 13 (the state of the elastic member 13 in the single stretchable sheet 10). In addition, in FIG. 14, illustration of the 2nd fusion part pair 16 (2nd fusion part 16a, 16b) is abbreviate|omitted.

In the long belt-shaped laminated body 14 before cutting, a plurality of elastic members 13 are each in an extended state as shown in FIG. 14(a). If the stretched elastic member 13 is cut together with the first sheet 11 and the second sheet 12 as described above to release the stretched state, as shown in FIG. 14(b), the elastic member 13 relaxes and the elastic member The length of the elastic member 13 is shortened, and the width direction length (diameter) of the elastic member 13 is increased. At this time, the diameter of the elastic member 13 is equal to or greater than the interval D between the pair of first fusion portions 15. Therefore, by releasing the stretched state of the elastic member 13, the portion of the elastic member 13 sandwiched between the pair of first fusion portions 15 The adhesiveness with the first fusion portion pair 15 is improved compared to the adhesiveness before relaxation (before the extended state is released). That is, the elastic member 13 and the first fusion portion pair 15 (first fusion portion 15a, 15b) are connected to the elastic member 13 before the extended state of the elastic member 13 is released (before the laminate 14 is cut), as shown in FIG. 14(a). Contact (ie, zero adhesion), or even if they are in contact with each other, the degree of plastic deformation of the elastic member 13 is not substantially generated and the elastic member 13 is released after the elongation state of the elastic member 13 is released (the laminated body 14 is cut). After breaking), due to the relaxation of the elastic member 13, the elastic member 13 is pinched by the first fusion portion 15a, 15b from both sides in the Y direction to produce a high degree of adhesive contact with plastic deformation. That is, in the single stretchable sheet 10 obtained by cutting the laminate 14, each of the plurality of elastic members 13 does not use an adhesive in the first fusion portion pair 15 but only uses the first sheet 11 and the second The two sheets 12 are fixed to the two sheets 11 and 12 by friction.

However, in the conventional manufacturing method of a stretchable sheet, as described above, there is a problem that the elastic member is unintentionally cut by the fusion process of the sheets due to the meandering of the elastic member. This problem also occurs in the above-mentioned manufacturing method of the stretchable sheet 10 using the manufacturing apparatus 100. That is, in the method of manufacturing the stretchable sheet 10, there is a concern that the elastic member 13 is meandering before forming the first fusion portion pair 15 with the horn 31, and when the first fusion portion pair 15 is formed, the elastic member 13 and the sheet 11, 12 is pressed together by the welding head 31 and cut off.

However, in the present invention, regarding the elastic member 13, the "elongation rate in the extended state in the above-mentioned fusion portion forming step", that is, the "elongation rate when the elastic member 13 is conveyed in the extended state" (hereinafter, also referred to as "Transport elongation rate") is higher than "the elongation rate when the stretchable sheet 10 as a manufactured product is in a natural state (non-extended state)" (hereinafter also referred to as "product elongation rate"), thereby eliminating the above concerns . That is, according to the method of manufacturing a stretchable sheet of the present invention, the above-mentioned magnitude relationship (transport elongation> product elongation) is established for the elastic member 13. Furthermore, in the present invention, the transport elongation is not only greater than the product elongation The elongation rate is greater than the conveying elongation rate in the previous manufacturing method of the stretchable sheet, thereby effectively suppressing the cutting of the elastic member 13 during the manufacture of the stretchable sheet. Therefore, regardless of the elongation rate of the product, All stretchable sheets can be manufactured stably. The detailed reason is as follows.

The width direction length of the elastic member 13 (length and diameter in the Y direction) is that the higher the elongation of the elastic member 13, the shorter, the lower the elongation of the elastic member 13 is, the thicker it is, but regarding the elongation of the elastic member 13 When the above-mentioned magnitude relationship (transport elongation> product elongation) is established, after the fusion portion forming step is performed and before the elastic member relaxation step is performed, the state can be as follows, that is, as shown in Figure 14(a) , The width direction length of the elastic member 13 in the extended state is shorter than the interval D between the first fusion portion pair 15 between the elastic member 13 and the first fusion portion 15a, 15b constituting the first fusion portion pair 15 Create a gap. That is, since the above-mentioned magnitude relationship (transport elongation> product elongation) is established, immediately before the fusion portion forming step is performed (immediately before the first fusion portion pair 15 is formed), the elastic member 13 in the extended state is arranged with the first The fusion portion pair 15 (the first fusion portion 15a, 15b) is formed at a predetermined distance from the CD. Therefore, it is possible to effectively suppress the formation of the first fusion portion pair 15 by the welding head 31 according to the schedule. When the predetermined position is pressed, the elastic member 13 is unintentionally pressed and cut off. In addition, the establishment of the above-mentioned magnitude relationship (conveying elongation>product elongation) is related to conveying the elastic member 13 at a high elongation when manufacturing the stretchable sheet 10, and is related to suppressing the meandering of the elastic member 13 during conveyance. In addition, if the meandering of the elastic member 13 during transportation is suppressed, the disadvantage that the elastic member 13 is unintentionally cut during the production of the stretchable sheet 10 is also suppressed.

In the previous method of manufacturing a stretchable sheet, the above-mentioned relationship (transport elongation> product elongation) is not substantially established, and the conveying elongation is substantially the same as the product elongation. In other words, the conveying elongation is less than the product elongation. It is sufficiently large. Therefore, immediately before the above-mentioned fusion portion forming step, the predetermined position of the first fusion portion pair 15 and the elastic member 13 in the extended state are easily overlapped. Therefore, the elastic member 13 is formed when the first fusion portion pair 15 is formed. It is easy to be cut off by being pressed by the welding head 31. As one of the reasons for making the conveying elongation and the product elongation substantially the same in the prior art, it is possible to prevent or minimize the falling off of the so-called elastic member (rubber thread). That is, in the past, it was avoided that the end of the elastic member in the stretchable sheet in the extension direction (stretch direction) is formed as the following elastic member non-arrangement area 13N (refer to FIG. 16). The gap between the elastic member between the fusion part pair and each fusion part in the expansion and contraction direction" (the area where the fusion part pair is used to pinch the elastic member but the elastic member is not arranged) tends to be strong. Therefore, in order to make use of The compression effect of the fusion portion on the obtained elastic member is quickly manifested after the elastic member's extended state is released, and the conveying elongation is set to be substantially the same as the product elongation, so that the stretched elastic member is separated from the elastic member. The length between the fusion parts on both sides of the component is as short as possible. On the other hand, in this embodiment, in order to solve the problem of cutting or meandering of the elastic member during the manufacture of the stretchable sheet, which was previously regarded as a problem, instead of allowing the elastic member to fall off to a certain degree, the above is the same. As mentioned, the conveying elongation> product elongation is adopted for the elastic member, so that the conveying elongation is not only greater than the product elongation, but also larger than the conveying elongation in the previous manufacturing method of the stretchable sheet.

The "elongation rate of the elastic member" mentioned in the present invention is an indicator of the tension of the elastic member, and it indicates how many percent of the elastic member is stretched when the length of the elastic member in its natural state (non-elongated state) is set to 100 By. For example, when the elastic member stretches and its length becomes 120, the elongation rate is 120%.

The ratio of the conveying elongation of the elastic member 13 to the product elongation is based on the establishment of the above-mentioned relationship (transporting elongation> product elongation). As the conveying elongation/product elongation, it is preferably 1.2 or more, more preferably 1.5 Above, and preferably 3.0 or less, more preferably 2.7 or less. The transport elongation of the elastic member 13 is based on the establishment of the above-mentioned relationship (transport elongation>product elongation), and is preferably 200% or more, more preferably 220% or more, and still more preferably 240% or more. The upper limit of the transport elongation of the elastic member 13 is not particularly limited. From the viewpoint of preventing the elastic member 13 from being cut due to high elongation, it is preferably 440% or less, more preferably 420% or less, and more Preferably, it is 400% or less. The product elongation rate of the elastic member 13 is not particularly limited, and can be appropriately set according to the use of the stretchable sheet 10 and the like. For example, when the stretchable sheet 10 is used as a constituent member of absorbent articles such as disposable diapers, the product elongation of the elastic member 13 is preferably 150% or more, more preferably 170% or more, and more preferably 400 % Or less, more preferably 380% or less.

From the viewpoint of ensuring that the above-mentioned magnitude relationship (transport elongation> product elongation) is established reliably and the effect of suppressing the meandering during transportation of the elastic member 13 is more stably exhibited, "constitutes one of the first fusion portion pair 15 The length D between the fusion portion 15a and the other fusion portion 15b (the interval D between the first fusion portion 15) is relative to the width direction length (diameter) of the elastic member 13 in the above-mentioned fusion portion forming step in the extended state "The ratio of ", that is, referring to Figure 14(a) describing the elastic member 13 in the stretched state, "the interval D between the first fusion portion pair 15/the widthwise length of the stretched elastic member 13" is preferably 1.3 or more, It is more preferably 1.5 or more, more preferably 3.5 or less, and more preferably 3.3 or less. The adjustment of the above-mentioned ratio (interval D/width direction length of the elastic member 13 in the stretched state) can be implemented by appropriately adjusting the elongation (stretching force) of the elastic member 13 when the stretchable sheet 10 is manufactured, or by The opening width c (refer to FIG. 13) of the 1st convex part pair 41 of the receiving roller 40 corresponding to the interval D is adjusted and implemented, and it is also possible to implement combining the two.

From the viewpoint of ensuring that the above-mentioned magnitude relationship (conveying elongation> product elongation) is established reliably and the specific effects of the present invention can be more stably exerted, it is preferable to carry out the elongation of the elastic member 13 in the step of forming the fusion portion The ratio is adjusted so that the diameter of the elastic member 13 does not reach 80% of the interval D of the first fusion portion 15 and is particularly preferably adjusted to 75% or less, especially 70% or less. In addition, there is no particular limitation on the lower limit of the ratio of the diameter of the elastic member 13 to the interval D, and it prevents cutting due to excessive elongation of the elastic member 13 in the step of forming the fusion portion, and prevents abrasion of the guide roller. From a viewpoint, it is preferably 30% or more, more preferably 35% or more, and still more preferably 40% or more.

The interval D between the pair of first fusion portions 15 may be appropriately adjusted according to the desired product elongation of the elastic member 13, and is not particularly limited. It is preferably 0.12 mm or more, more preferably 0.2 mm or more, and more preferably 0.7 mm or less, more preferably 0.6 mm or less. When setting the interval D of the first fusion portion pair 15, the following method can be used. That is, a calibration curve showing the relationship between the product elongation of the elastic member 13 and the interval D is prepared in advance, and the desired product elongation is set based on the calibration curve. The rate corresponds to the interval D. In addition, the distance D between the first fusion portion pair 15 relative to the widthwise length a (refer to FIG. 13) in the extended state of the elastic member 13 in the fusion portion forming step is preferably more than 1.0 times and 2.0 times the following.

Furthermore, as described above, the interval D between the pair of first fusion portions 15 is approximately equivalent to the length of the first concave portion 43 along CD, that is, the opening width c of the first convex portion pair 41 along CD (refer to FIG. 13) Therefore, regarding the opening width c, in relation to the diameter a (see FIG. 13) of the elastic member 13 in the stretched state in the above-mentioned fusion part forming step, it is also preferable to set the above-mentioned range. The diameter a of the elastic member 13 in the extended state relative to the depth b of the first recess 43 (see FIG. 13) is preferably 1.1 times or more and 1.5 times or less, more preferably 1.2 times or more and 1.5 times or less, and more preferably 1.3 times 1.5 times the above.

The length in the width direction of the elastic member 13 in the extended state in the above-mentioned fusion portion forming step, that is, the diameter a of the elastic member 13 in the extended state (see FIG. 13) is closely related to the conveying elongation of the elastic member 13. That is, if the transport elongation of the elastic member 13 is high, the width direction length (diameter a) of the elastic member 13 in the extended state becomes shorter, and if the transport elongation of the elastic member 13 is low, the elastic member 13 is in the extended state The lower width direction length (diameter a) becomes longer. According to this tendency, in terms of the establishment of the above-mentioned magnitude relationship (conveying elongation> product elongation) and the viewpoint of preventing the elastic member 13 from being cut due to high elongation, the elastic member in the step of forming the fusion portion The length in the width direction (diameter a) in the extended state of 13 is preferably 0.1 mm or more, more preferably 0.2 mm or more, and preferably 0.5 mm or less, more preferably 0.4 mm or less.

The first sheet 11 and the second sheet 12 and the elastic member 13 constituting the stretchable sheet 10, or the degree of elongation of the elastic member 13 when the stretchable sheet 10 is manufactured, and the opening of the first recess 43 along the Y direction The width can also be appropriately set according to the desired state of elongation in the stretchable sheet 10. The degree of elongation of the elastic member 13 housed in the first recess 43 can also be adjusted in such a way that the stretchable sheet 10 has a desired extensibility (elongation) or a desired fold structure. For example, the degree of elongation of the elastic member 13 can be adjusted by appropriately adjusting the depth or width of the first recess 43 (first fusion portion interval D). Hereinafter, the preferable structure which the manufacturing method of the stretchable sheet 10 can have from the viewpoint of making the formation of the porosity change region 20 easier will be described.

From the viewpoint of easy formation of the porosity change region 20, it is preferable to use the first sheet in the laminated body 14 when the laminated body 14 is supplied to the ultrasonic processing part 101 as the fusion device in the above-mentioned manufacturing method. The depth or width of the first recess 43 is adjusted so that there is no gap between the material 11, the elastic member 13 and the second sheet 12. From the same viewpoint as the above, the size of the first recess 43 is preferably within the following range. The width c of the first recess 43 (refer to FIG. 13) is based on the premise that the elastic member 13 and the first sheet 11 are housed in the first recess 43, and is the diameter a of the elastic member 13 in the extended state (refer to FIG. 13) It is preferably more than 1.0 times and 2.0 times or less. The diameter a (refer to FIG. 13) of the elastic member 13 in the stretched state is the depth b (refer to FIG. 13) of the first recess 43, preferably 1.0 times or more and 1.2 times or less, more preferably 1.05 times or more and 1.2 times or less, and more Preferably, it is 1.1 times or more and 1.2 times or less.

From the viewpoint of easy formation of the porosity change region 20, the line pressure of the welding head 31, that is, the pressure applied to the laminated body by pressing the welding head 31 against the laminated body is preferably 2 N/mm or more, and Preferably it is 2.2 N/mm or more, more preferably 3 N/mm or less, more preferably 2.7 N/mm or less, preferably 2 N/mm or more and 3 N/mm or less, more preferably 2.2 N/mm or more 2.7 N/mm or less.

As described above, in the manufacturing method of this embodiment, after the second sheet 12 is preheated, ultrasonic vibration is applied to the second sheet 12. The inventors of the present invention found that by preheating the second sheet 12 before ultrasonic vibration is applied to the second sheet 12, the void ratio change region 20 formed by ultrasonic vibration and the elastic member 13 are not fused. It is considered that the reason is that the second sheet material obtains heat energy by preheating. Therefore, the weaker ultrasonic vibration can be used for sealing to the extent that the elastic member 13 can be fixed from both sides thereof. Furthermore, it is considered that the reason is that because the ultrasonic vibration is weak, the frictional heat between the fibers caused by the ultrasonic vibration generated inside the second sheet 12 is higher than that generated at the interface between the second sheet 12 and the elastic member 13 The above-mentioned frictional heat is high. On the other hand, if ultrasonic vibration is applied to the second sheet without preheating, the second sheet and the elastic member overlapping the second sheet are fused between the pair of fusion portions 15a and 15b. From the viewpoint of further suppressing the fusion of the second sheet 12 and the elastic member 13, the preheating temperature of the second sheet 12 is preferably lower than the melting point of the constituent fibers of the second sheet 12. From the same viewpoint as above, the preheating temperature of the second sheet 12 is preferably lower than the melting point of the constituent fibers of the second sheet 12 by 90°C to 135°C, and more preferably 95°C to 130°C lower. It is more preferably 100°C to 125°C lower. For example, when the constituent fiber of the second sheet 12 is a single fiber containing polypropylene, especially a homopolymer of propylene (for example, a melting point of 163°C), the preheating temperature of the second sheet 12 is preferably set to 40 ℃ (relative to the melting point-123 ℃) ~ 60 ℃ (melting point-103 ℃) range. From the viewpoint of easier preheating of the second sheet 12, the temperature of the receiving roll 40 is preferably set to a range of 90°C to 135°C lower than the melting point of the constituent fibers of the second sheet 12. The melting point of the constituent fibers of the second sheet 12 refers to the melting point of the resin with the lowest melting point among the constituent resins of the constituent fibers in the second sheet 12. The melting point of the constituent fibers can be measured by thermal analysis using a differential scanning calorimeter (for example, DSC6200 manufactured by Seiko Instruments Inc.). Specifically, thermal analysis is performed on a fiber sample (1 mg) obtained by finely cutting any ten points of the fiber web or non-woven fabric at a heating rate of 10°C/min, and the melting peak temperature of the measured fiber constituents is set It is the melting point of the fiber. When there are multiple melting peak temperatures, the lowest melting peak temperature among them is set as the melting point of the constituent fiber.

The stretchable sheet 10 of this embodiment can be used as a constituent material of absorbent articles such as disposable diapers and menstrual sanitary napkins, and can be particularly used for the purpose of forming stretchable parts of absorbent articles. Absorbent articles are mainly used to absorb and maintain body fluids excreted from the body such as urine and menstrual blood. Absorbent articles include, for example, disposable diapers, menstrual napkins, incontinence pads, sanitary pads, etc., but are not limited to these, and widely include articles for absorbing liquid discharged from the human body. As an absorbent article, for example, an absorbent body provided with an absorbent body having a front sheet, a back sheet, and a liquid-retaining body arranged between the two sheets, and a non-skin facing surface of the absorbent body Those who wear the body outside the side. As described above, the stretchable sheet of the present invention can be preferably used for exterior bodies. The absorbent article may further include various members corresponding to its specific use. Such components are well known to the industry.

Next, the absorbent article of the present invention will be described. The above-mentioned absorbent article has a longitudinal direction corresponding to the front and back direction of the wearer, that is, the direction extending from the abdominal side to the back side through the crotch part (the direction indicated by the symbol "X1" in the figure), and the transverse direction (in the figure) orthogonal to the longitudinal direction. The direction indicated by the number "Y1"). In the following description, unless otherwise mentioned, the longitudinal direction is along the longitudinal direction of the absorbent article or its constituent members (for example, absorbent body), and the lateral direction is along the transverse direction of the absorbent article or its constituent members. In the horizontal direction. In one embodiment of the above-mentioned absorbent article, it is divided into the following three: the lower part of the crotch (the part denoted by the symbol "B" in the figure), which is arranged in the wearer's crotch and includes the wearer's penis and other excretion parts The opposite excretion part (not shown); the ventral part (the part represented by the symbol "A" in the figure), which is arranged on the ventral side (front side) of the wearer than the lower part of the crotch; and the back The side part (the part denoted by the symbol "C" in the figure) is arranged on the wearer's back side (rear side) than the lower part of the crotch. In one embodiment of the above-mentioned absorbent article, an absorber (a member represented by a symbol "5" in the figure) that absorbs and retains excretion fluid such as urine is provided. The disposable diaper 1 which is one embodiment of the absorbent article of this invention is shown in FIG. 15 and FIG. 16, and the diaper 1 has the said structure.

In this specification, the "skin facing surface" refers to the surface of the absorbent article or its constituent members (such as absorbent body) that faces the wearer's skin when the absorbent article is worn, that is, the surface that is relatively close to the wearer's skin. On the side, the "non-skin facing surface" refers to the surface of the absorbent article or its constituent members that faces the side opposite to the skin side when the absorbent article is worn, that is, the side relatively far away from the wearer's skin. Furthermore, the "wearing time" mentioned here refers to the state of maintaining the usual proper wearing position, that is, the correct wearing position of the absorbent article.

The diaper 1 is a so-called underpants-type disposable diaper, and as shown in FIG. 15, it has a pair of side seal parts S, S, a waist opening part WH, and a pair of leg opening parts LH, LH. More specifically, the diaper 1 is provided with an absorbent body 2 including an absorbent body 5, and an outer garment arranged on the side farther from the wearer's skin than the absorbent body 2, that is, on the non-skin facing side of the absorbent body 2. The body 7, the ventral portion A and the back portion C are joined to each other along the longitudinal X1 side edges 7S of the exterior body 7 to form a pair of side seals S, S, a waist opening WH, and a To the leg openings LH, LH. The absorbent body 2 and the exterior body 7 are joined by an adhesive. The absorptive main body 2 has a rectangular shape in plan view so that its longitudinal direction coincides with the longitudinal direction X1 of the diaper 1, and extends from the abdominal part A to the back part C through the crotch part B and extends in the longitudinal direction X1.

Typically, the abdominal part A and the back part C each include a part located at the same position as the side seal part S in the longitudinal direction X1, that is, the abdomen part that is arranged around the wearer's abdomen when the diaper 1 is worn. The abdominal part A is a part of the front body of the diaper 1, and the back part C is a part of the rear body of the diaper 1. The crotch part B exists from the front part of the diaper 1 to the back part. In the present invention, the abdomen part A, the crotch part B, and the back part C may be the regions when the diaper 1 in the unfolded and extended state is divided into three equal parts in the longitudinal direction X1.

The absorbent body 2 includes a liquid-permeable front sheet 3 arranged relatively close to the wearer's skin, and a liquid-impermeable or difficult liquid-permeable or water-repellent ( In short, the back sheet 4 of leak-proofness) and the absorber 5 interposed between the two sheets 3 and 4 are constituted. The members 3, 4, and 5 constituting the absorbent main body 2 are integrally formed by a known joining method such as an adhesive. A pair of leak-proof flanges 6 and 6 are provided on both sides of the absorbent body 2 along the longitudinal direction X1. Each leak-proof cuff 6 includes a liquid-resistant or water-repellent and air-permeable sheet 60 for forming a leak-proof cuff, and an elastic member 61 fixed to the sheet 60 in an extended state. As each of the above-mentioned members 3 to 6, members generally used in such absorbent articles can be used without particular limitation.

In this embodiment, the exterior body 7 each independently includes a ventral exterior body 7A that constitutes the ventral portion A (front body piece) and a back exterior body 7C that constitutes the back portion C (back body piece). The absorbent body 2 is erected and fixed between the two exterior bodies 7A and 7C. Each of the two exterior bodies 7A and 7C has a rectangular shape in the unfolded and extended state of the diaper 1 as shown in FIG. 16. The "unfolded and stretched state" mentioned here means that the diaper 1 is cut at the side seal portion S and set to the unfolded state, and the diaper 1 in the unfolded state is expanded until the elastic members of each part are stretched and become the design size (with Extend the state from which all the effects of the elastic member have been eliminated to the same size as the plane.

The diaper 1 includes a stretchable sheet 10A having stretchability in the transverse direction Y1. The stretchable sheet 10A is configured in the same manner as the above-mentioned stretchable sheet 10 except that it does not have the second fusion portion pair 16 (second fusion portion 16a, 16b), that is, the fusion portion pair that is not in contact with the elastic member 13, and The elastic member 13 is pinched by the first fusion portion pair 15 (first fusion portion 15a, 15b) (hereinafter, also simply referred to as "fusion portion pair 15", "fusion portion 15a", and "fusion portion 15b"). The description about the above-mentioned stretchable sheet 10 can be suitably applied to the structure which is not specifically demonstrated about the stretchable sheet 10A.

In this embodiment, the plurality of elastic members 13 constituting the stretchable sheet 10A are respectively clamped by the plurality of fusion portion pairs 15 in a state of being stretched at a specific elongation in the transverse direction Y1. That is, in the stretchable sheet 10A, the plurality of elastic members 13 are respectively formed between one of the fusion portions 15a and the other fusion portion 15b of the pair of fusion portions 15, and only the first sheet 11 and the second sheet 12 is fixed between the two sheets 11 and 12 by friction, and is not fixed between the two sheets 11 and 12 by bonding methods such as adhesive or fusion.

In the present embodiment, the exterior body 7 (ventral exterior body 7A, back exterior body 7C) includes a stretchable sheet 10A, and more specifically, the exterior body 7 includes a stretchable sheet 10A. In this embodiment, of the two sheets 11 and 12 included in the stretchable sheet 10A constituting the exterior body 7, the first sheet 11 is arranged at a position relatively away from the absorbent body 5 (absorbent body 2). On the outer surface of the diaper 1, the second sheet 12 is disposed relatively close to the absorbent body 5 (absorbent main body 2) to form the inner surface of the diaper 1. Furthermore, contrary to the form shown in the figure, the second sheet 12 may be arranged at a position relatively far away from the absorber 5 and the first sheet 11 may be arranged at a position relatively close to the absorber 5. Compared with the second sheet 12 arranged relatively close to the absorber 5, the first sheet 11 arranged at a position relatively far away from the absorber 5 has a longer length in the longitudinal direction X1, and has a longitudinal direction from the second sheet 12 The extension part 11E from which the end edge of X1 extends is folded back toward the skin-facing surface of the second sheet 12 to cover the end part of the absorptive main body 2 in the longitudinal direction X1.

The diaper 1 is characterized in that there is an elastic member non-arrangement area 13N where the elastic member 13 is not arranged at the end of the stretchable sheet 10A in the transverse direction Y1, in other words, the edge along the longitudinal direction X1.

In the present embodiment, the elastic member non-arrangement area 13N is present at both ends of the lateral Y1 (on both sides along the longitudinal direction X1) of the ventral exterior body 7A and the back exterior body 7C, as shown in FIG.部), and includes the side seal S. The elastic member non-arrangement region 13N exists over the entire length of each of the two exterior bodies 7A and 7C in the longitudinal direction X1.

As shown in FIG. 17, the elastic member non-arrangement area 13N includes a plurality of fusion portion pairs 15 intermittently arranged in the lateral direction Y1, at least the lateral outermost fusion portion pair 15 located at the outermost side of the lateral direction Y1, and the lateral outermost fusion portion The pair 15 is the other fusion part pair 15 closest to the lateral direction Y1. That is, for a plurality of welded portion pairs 15 located on one elastic member 13 extending in the transverse direction Y1 or on the imaginary extension line of the one elastic member 13, the transverse outermost welded portion pair 15 is regarded as the first, from the transverse direction Y1 When numbers are given sequentially from the outside to the inside, the elastic member non-arrangement area 13N includes at least the second fusion portion pair 15 and an area located on the outer side of the lateral direction Y1 than the second fusion portion pair 15, and is used throughout. There is no area where the elastic member 13 is arranged in the entire area. In the form shown in the figure, the elastic member non-arrangement area 13N further includes the second fusion portion pair 15 and the third fusion portion pair 15.

The stretchable sheet 10A is manufactured by the same method as the stretchable sheet 10 described above, and regarding the elastic member 13, the above-mentioned magnitude relationship (transport elongation>product elongation) is established. Typically, the conveying elongation of the elastic member 13 during the manufacture of the stretchable sheet 10A is set to be higher than before. Therefore, when the stretchable sheet 10A is manufactured, the elastic member 13 is cut to release the elasticity when the stretched state is released. The degree of shrinkage of the member 13 is greater than before. Therefore, the position of the cut end of the elastic member 13 in the stretchable sheet 10A as a manufactured product is closer to the inner side of the transverse direction Y1 (closer to the absorbent body 2 than the previous product like the stretchable sheet 10Z). ), as a result, the fusion portion pair 15 generated at both ends of the transverse direction Y1 of the stretchable sheet 10A, specifically, the above-mentioned first and second fusion portion pair 15 is in a state where the elastic member 13 is not arranged, An elastic member non-arrangement area 13N is formed.

The stretchable sheet 10A is the same as the stretchable sheet 10 described above, and the elastic member 13 is fixed to the sheets 11 and 12 by "pressing", and no adhesive is used for this fixing. Therefore, in the elastic member non-arrangement area 13N, no adhesive such as a hot melt adhesive exists at least on the imaginary extension line of the elastic member 13. Typically, no adhesive is present in the entire area of the elastic member non-arrangement area 13N.

As shown in FIG. 17, the ends of the elastic member 13 in the transverse direction Y1 are located in the fusion part pair 15. In other words, the boundary between the elastic member non-arrangement area 13N and the elastic member 13 arrangement area is located in the fusion part pair 15. In the form shown in the figure, the end of the elastic member 13 in the transverse direction Y1 (the boundary between the elastic member non-arrangement area 13N and the elastic member 13 arrangement area) is located in the third fusion portion pair 15. The term "located in a pair of fusion portions" mentioned here includes not only the case where the end of the elastic member 13 in the transverse direction Y1 overlaps the pair of fusion portions 15 (between fusion portions 15a and 15b), but also includes the location near the pair of fusion portions 15 (specifically In other words, the distance from the fusion portion pair 15 is preferably within 5 mm, more preferably within 3 mm).

Fig. 18 shows a diaper 1Z which is a typical example of the conventional shorts-type disposable diaper. The diaper 1Z is configured in the same manner as the diaper 1 except that the exterior body 7 includes the stretchable sheet 10Z. The stretchable sheet 10Z is the previous product of the "stretchable sheet using compression". The main difference from the stretchable sheet 10A of the present invention is the above-mentioned relation between the conveying elongation rate of the elastic member 13 and the product elongation rate ratio. That is, as described above, the stretchable sheet 10A is "transport elongation>product elongation", while the previous stretchable sheet 10Z is roughly "transport elongation=product elongation".

Due to the above-mentioned difference, in the diaper 1Z of the previous product, as shown in FIG. 18, in the exterior body 7 (stretchable sheet 10Z), a plurality of elastic members 13 respectively reach the lateral outermost fusion part pair (first One pair of fusion portions) 15, and further, the end portion (cut end portion) of each elastic member 13 in the lateral direction Y1 extends from the first pair of fusion portion 15 toward the outside of the lateral direction Y1. In FIG. 18, the ends of the elastic members 13 extending from the first fusion portion pair 15 are arranged in a uniformly curved form in a plan view, but in actual diapers, they are arranged in a scattered form. More, leaving a messy impression. In contrast, the outer body 7 (stretchable sheet 10A) of the diaper 1 of the present invention, as shown in FIGS. 16 and 17, the elastic member non-arrangement region 13N is located at both ends of the transverse direction Y1, and the elastic member 13 is in the transverse direction The end of Y1 is located in the fusion part pair 15 and does not extend from the fusion part pair 15 to the outside of the lateral direction Y1 as much as in the diaper 1Z. Therefore, the appearance is better than that of the diaper 1Z. In addition, in the stretchable sheet 10A, the method of fixing the elastic member 13 to the sheets 11 and 12 is not by bonding or fusion with an adhesive, but by using the fusion part pair 15 (fusion part 15a, fusion part 15a, fusion part 15a, 15b). Therefore, even if the end (cut end) of the elastic member 13 in the transverse direction Y1 is within the definition of "located in the fusion part pair" above, it slightly extends from the fusion part pair 15 to the outside of the transverse direction Y1. Since the fusion portion pair 15 functions as a guide for restricting the position of the cut end of the elastic member 13, it is easy to be in a state where the cut ends of the plurality of elastic members 13 are neatly arranged, and the diaper 1 The appearance can be improved.

Furthermore, in this embodiment, as shown in FIG. 15, the surface (skin-facing surface and non-skin-facing surface) of the stretchable sheet 10A constituting the exterior body 7 is formed with the above-mentioned fold structure including the convex portion 17 Therefore, in this respect, the appearance of the diaper 1 is also excellent. The stretchable sheet 10A does not have the second fused portion pair 16 (the second fused portions 16a, 16b), but nevertheless, the fold structure may be formed in the same manner as the stretchable sheet 10. Furthermore, in the diaper 1, of course, the elastic sheet 10 which has the 2nd fusion part pair 16 can be used instead of the elastic sheet 10A, and in this case, the fold structure can be formed more stably.

The length of the elastic member non-arrangement area 13N in the transverse direction Y1, that is, "from the end of the outer casing 7 (stretchable sheet 10A) in the transverse direction Y1 (the side edge along the longitudinal direction X1) throughout the transverse direction Y1 of the elastic member 13 The length of the end portion" (hereinafter, also referred to as "the missing length of the elastic member 13 13NL") is not particularly limited, but from the viewpoint of the balance between the improvement of the appearance of the diaper 1 and the guarantee of the stretch range, it is relative to the stretchable sheet The overall length of the lateral Y1 of the material 10A (exterior body 7) is preferably 5% or more, more preferably 8% or more, and more preferably 15% or less, more preferably 12% or less. The missing length 13NL of the elastic member 13 is preferably 10 mm or more, more preferably 20 mm or more, and preferably 100 mm or less, more preferably 80 mm or less.

The absorbent article of the present invention is not limited to the shorts-type disposable diaper as in the above-mentioned embodiment, and widely includes articles for absorbing body fluids (urine, menstrual blood, soft stools, sweat, etc.) discharged from the human body, and also includes articles with so-called sticky Expansion type disposable diapers with buckles, menstrual sanitary napkins, sanitary underwear, etc.

As mentioned above, the present invention has been described based on its preferred embodiments, but the present invention is not limited to the above-mentioned embodiments and can be changed as appropriate. For example, in the stretchable sheet 10 of the above embodiment, the pair of first fusion portions 15a, 15b and the second fusion portions 16a, 16b are intermittently provided on the same straight line in the Y direction, but these fusion portions 15a , 15b, 16a, 16b can also be continuous on the same straight line in the Y direction. In the above-mentioned embodiment, the first fusion portion 15a, 15b and the second fusion portion 16a, 16b have a rectangular shape, but instead of this, shapes such as an ellipse, a circle, or a rhombus may be adopted.

In addition, in the above-mentioned embodiment, the stretchable sheet 10 has a plurality of elastic members 13, but the stretchable sheet 10 may have one elastic member 13.

Moreover, in the manufacturing method of the above-mentioned embodiment, as the method of forming the fusion portion pair 15, 16 fusion based on ultrasonic processing is used, but fusion based on embossing with heat may also be used. In addition, in the diaper 1 of the above-mentioned embodiment, it is a form in which the exterior body 7 independently has a member constituting the abdominal part A (front body piece) and a member constituting the back part C (back body piece), The absorptive main body 2 is erected and fixed to the two members, and instead of this, it may be a form that continuously extends from the abdominal part A to the dorsal part C.

Regarding the above-mentioned embodiment, the present invention further discloses the following stretchable sheet, an absorbent article provided with the same, and a manufacturing method of the stretchable sheet. ＜1＞ A stretchable sheet having a first sheet including a fiber sheet, a second sheet disposed opposite to the first sheet and including a fiber sheet, and disposed between the two sheets in an extended state and An elastic member extending in one direction, and having elasticity along the extending direction of the elastic member, The first sheet and the second sheet are joined by a plurality of fusion portions which are located on both sides of the elastic member via the elastic member and are formed at intervals along the extending direction of the elastic member, The elastic member is located in a space formed by the fusion part, the first sheet and the second sheet located on both sides of the elastic member via the elastic member, and only by the surface of the elastic member and the first sheet The friction between the second sheet and the second sheet is fixed between the two sheets, When the stretchable sheet is observed in a cross-section in a direction orthogonal to the extension direction of the elastic member at the position where the fusion portion is formed, the length of the contact between the first sheet and the elastic member is longer than that of the second sheet and the elastic member. The connecting length of the components is long, When the stretchable sheet is viewed in a cross-section in a direction orthogonal to the extending direction of the elastic member at the position where the fusion portion is formed, the second sheet has a porosity change in the region overlapping with the elastic member in the thickness direction The void ratio change region is that the central portion in the above-mentioned orthogonal direction has a relatively higher void ratio between the constituent fibers than the two sides across the central portion, and In the above-mentioned porosity change region, a part of the constituent fibers loses the fiber shape and becomes a melted and solidified state, and the remaining part of the constituent fibers maintains the fiber shape.

＜2＞ The stretchable sheet as in the above <1>, wherein when the stretchable sheet is viewed in a cross-section perpendicular to the extending direction of the elastic member at the position where the fusion portion is formed, the first sheet of the elastic member The part on the side bulges toward the outside in the thickness direction of the stretchable sheet compared to the part on the second sheet side of the elastic member, and When the above-mentioned elastic member is halved in the thickness direction in the cross-sectional observation, the second sheet side and the first sheet side of the elastic member have an asymmetrical shape. ＜3＞ As the above-mentioned stretchable sheet of <2>, when viewed in a cross-section in a direction orthogonal to the extending direction of the elastic member, the second sheet side of the elastic member is the above-mentioned fusion located on both sides of the elastic member The part between the parts becomes a substantially flat part compared to the part other than the fusion part. ＜4＞ The stretchable sheet of the above-mentioned <2> or <3>, in which the surface on the second sheet side is substantially flat between the fusion portions, and on the other hand, the surface on the first sheet side bulges toward the outer side in the thickness direction. ＜5＞ The stretchable sheet according to any one of the above <1> to <4>, wherein the porosity change area has a shape following the shape of the elastic member. ＜6＞ The stretchable sheet according to any one of the above <1> to <5>, wherein when the stretchable sheet is viewed in a cross section in a direction orthogonal to the extending direction of the elastic member at the formation position of the fusion portion, The surface facing the elastic member of the second sheet is in close contact with the elastic member. ＜7＞ The stretchable sheet according to any one of the above <1> to <6>, wherein the porosity change area is in close contact with the surface of the elastic member opposite to the porosity change area, and becomes a surface that follows the porosity change area. Shape of shape. ＜8＞ The stretchable sheet according to any one of the above <1> to <7>, wherein the porosity change region and the elastic member are not fused with each other. ＜9＞ The stretchable sheet of any one of the above <1> to <8>, in which the second stretchable sheet is observed in the cross-section of the stretchable sheet along the orthogonal direction at the formation position of the fusion part. When the area where the sheet material overlaps the elastic member is divided into three equal parts in the orthogonal direction, the central area is defined as the central portion, and when the areas located on both sides of the central portion are defined as side portions, The void ratio of the central portion is higher than that of the side portions. ＜10＞ The stretchable sheet of any one of the above <1> to <9>, wherein the porosity change region has a plurality of regions with different porosity, and In the above-mentioned plural areas, the porosity is different from each other, and the interface between the two adjacent areas in the above-mentioned orthogonal direction is not clear.

＜11＞ The stretchable sheet according to any one of the above <1> to <10>, wherein regarding the fusion portion located on both sides of the elastic member, the side edge of the elastic member in one fusion portion is fused with the other The interval between the side edges of the elastic member in the portion is set to D, and when the diameter of the elastic member in the relaxed state of the stretchable sheet is set to d2, the value of d2/D is 1.1 or more, preferably It is 1.2 or more, more preferably 1.3 or more. ＜12＞ The stretchable sheet of any one of the above <1> to <11>, wherein the elastic member in the relaxed state of the stretchable sheet has a fineness of 155 dtex or more and 1240 dtex or less, preferably 310 dtex or more and 940 Below dtex. ＜13＞ The stretchable sheet according to any one of the above <1> to <12>, wherein between the adjacent elastic members and the adjacent fusion portions in the orthogonal direction, there is arranged Other fusion parts where the first sheet and the second sheet are joined. ＜14＞ The stretchable sheet of the above-mentioned <13>, in which the other fusion part has a lower bonding strength than the fusion part. ＜15＞ The stretchable sheet as in the above <13> or <14>, wherein the bonding strength of the other fusion portion is 50% to 95%, preferably 60% to 90%, and more relative to the bonding strength of the fusion portion. Preferably, it is more than 70% and less than 80%. ＜16＞ The stretchable sheet of any one of the above <13> to <15>, wherein the length L4 of the other fusion portion along the orthogonal direction is relative to the fusion portion adjacent in the orthogonal direction The length L7 between the outer ends is 2% or more and 90% or less, preferably 10% or more and 80% or less. ＜17＞ The stretchable sheet of any one of the above <13> to <16>, wherein the length L4 of the other fusion portion along the orthogonal direction is 0.2 mm or more and 5.0 mm or less. ＜18＞ The stretchable sheet of any one of the above <13> to <17>, wherein the length L4 of the other fusion portion along the orthogonal direction is 0.4 mm or more and 3.0 mm or less. ＜19＞ The stretchable sheet according to any one of the above <1> to <18>, wherein the distance P1 between the fusion portions adjacent in the extension direction of the elastic member is relative to the fusion along the extension direction of the elastic member The length L5 of the part is 30% or more and 6000% or less, preferably 500% or more and 3000% or less. ＜20＞ The stretchable sheet according to any one of the above <1> to <19>, wherein the length L5 of the fusion portion along the extending direction of the elastic member is 0.1 mm or more and 3.0 mm or less.

<21> The stretchable sheet of any one of the above <1> to <20>, wherein the length L5 of the fusion portion along the extending direction of the elastic member is 0.4 mm or more and 1.0 mm or less. <22> The stretchable sheet according to any one of the above <1> to <21>, wherein the distance P1 between the fusion portions adjacent in the extending direction of the elastic member is 1.0 mm or more and 6.0 mm or less. <23> The stretchable sheet according to any one of the above <1> to <22>, wherein the distance P1 between the fusion portions adjacent in the extending direction of the elastic member is 2.0 mm or more and 4.0 mm or less. <24> The stretchable sheet of any one of the above <1> to <23>, wherein the length L7 between the outer ends of the fusion portion adjacent in the orthogonal direction is 1.0 mm or more and 10.0 mm the following. <25> The stretchable sheet of any one of the above <1> to <24>, wherein the length L7 between the outer ends of the fusion portion adjacent in the orthogonal direction is 1.4 mm or more and 5.0 mm the following. <26> The stretchable sheet of any one of the above <1> to <25>, wherein the distance P2 between the adjacent elastic members is 0.5 mm or more and 10.0 mm or less. <27> The stretchable sheet of any one of the above <1> to <26>, wherein the distance P2 between adjacent elastic members is 3.0 mm or more and 7.0 mm or less. <28> The stretchable sheet according to any one of the above <1> to <27>, wherein the first sheet and the second sheet are laminated non-woven fabrics having spunbonded non-woven fabric layers. <29> The stretchable sheet of any one of the above <1> to <28>, in which a non-woven fabric is used as the first sheet and the second sheet, and the basis weight of the non-woven fabric is 5 g/m ² or more 50 g/m ² or less, preferably 8 g/m ² or more and 30 g/m ² or less. <30> The stretchable sheet as in the above <29>, wherein the flexural strength of the non-woven fabric in the direction orthogonal to the machine travel direction is 50 cN or less, preferably 30 cN or less, and in the machine travel direction 70 cN or less, preferably 50 cN or less.

＜31＞ The stretchable sheet according to any one of the above <1> to <30>, wherein the first sheet and the second sheet are respectively formed with convex portions protruding in a direction away from the elastic member along the thickness direction. ＜32＞ The stretchable sheet of the above-mentioned <31>, wherein the first sheet and the second sheet are arranged between the adjacent elastic members and the adjacent fusion portions in the orthogonal direction. The other fusion part of the joint, and In the convex portion, the first sheet and the second sheet protrude so as to be separated from each other in the thickness direction, with the other fusion portion as the starting point of bending. ＜33＞ The stretchable sheet of the above <31> or <32>, wherein the convex portion is a part that is different from the portion where the first sheet and the second sheet overlap the elastic member at a position that follows the shape of the elastic member , And extend continuously along the above-mentioned orthogonal direction, and a plurality of folds are formed by the convex portion. ＜34＞ The stretchable sheet according to any one of the above <1> to <33>, wherein the first sheet contains a hydrophilic non-woven fabric composed of fibers obtained by imparting hydrophilicity to synthetic fibers containing a heat-fusible resin as constituent fibers. ＜35＞ The stretchable sheet according to any one of the above <1> to <34>, wherein in the stretchable sheet, the first sheet and the second sheet are two separate sheets. ＜36＞ The stretchable sheet of any one of the above <1> to <34>, wherein in the above stretchable sheet, the first sheet and the second sheet are formed by bending one sheet to face each other In the case of two sides, the part constituting one side is the first sheet, and the part constituting the other side is the second sheet. ＜37＞ An absorbent article comprising an absorbent body and an outer body located on the non-skin facing side of the absorbent body, and The said exterior body contains the stretchable sheet of any one of said <1> to <36>. ＜38＞ The absorbent article of the above-mentioned <37>, wherein the second sheet of the above-mentioned stretchable sheet is arranged so as to face the wearer's skin. ＜39＞ The absorbent article of the above-mentioned <37>, wherein the second sheet of the above-mentioned stretchable sheet is arranged so as to face the clothing side.

＜A1＞ A method for manufacturing a stretchable sheet, which is a method for manufacturing a stretchable sheet as follows. The stretchable sheet is an elastic member extending in one direction between two opposing sheets, and in the extending direction of the elastic member (X) is flexible, The fusion portions (first fusion portions 15a, 15b) of the two sheets are arranged close to the elastic member on both sides of the elastic member in the width direction (Y) via the elastic member to form a pair of fusion portions (the first fusion portion 15a, 15b). 1 fusion part pair 15), the fusion part pair is intermittently arranged in plural in the extending direction of the elastic member, The elastic member is compressed by a plurality of the fusion portions in a state of being stretched at a specific elongation in the extension direction of the elastic member, and The manufacturing method of the stretchable sheet includes: The step of forming a fusion part is to arrange an elastic member in a state of being stretched in one direction between two sheets, and the two sheets are placed at a plurality of positions on both sides of the elastic member in the width direction through the elastic member in the stretched state. The sheets are joined to each other to form a plurality of pairs of fusion portions; and The elastic member relaxation step is to release the stretched state of the elastic member to relax the elastic member, and by increasing the width direction length of the elastic member accompanying the relaxation, the elastic member is sandwiched between the fusion portion pair The adhesion between the part and the fusion part pair is improved compared to before relaxation, whereby the fusion part pair is used to pinch the elastic member in a state of elongation at a specific elongation rate; Regarding the elastic member, the elongation (conveying elongation) in the stretched state in the step of forming the fusion portion is made higher than the elongation (product elongation) of the stretchable sheet as a manufactured product in a natural state.

＜B1＞ A method for manufacturing a stretchable sheet, which is the method for manufacturing a stretchable sheet according to any one of the above <1> to <36>, the stretchable sheet is The fusion portion (first fusion portion 15a, 15b) of the two sheets including the first sheet and the second sheet is opposite to the elastic member on both sides of the elastic member in the width direction (Y) through the elastic member The pair of fusion portions (the first pair of fusion portions 15) are arranged in close proximity, and a plurality of the fusion portion pairs are intermittently arranged in the extending direction of the elastic member, The elastic member is compressed by a plurality of the fusion portions in a state of being stretched at a specific elongation in the extension direction of the elastic member, and The manufacturing method of the stretchable sheet includes: The step of forming a fusion part is to arrange an elastic member in a state of being stretched in one direction between two sheets, and the two sheets are placed at a plurality of positions on both sides of the elastic member in the width direction through the elastic member in the stretched state. The sheets are joined to each other to form a plurality of pairs of fusion portions; and The elastic member relaxation step is to release the stretched state of the elastic member to relax the elastic member, and by increasing the width direction length of the elastic member accompanying the relaxation, the elastic member is sandwiched between the fusion portion pair The adhesion between the part and the fusion part pair is improved compared to before relaxation, whereby the fusion part pair is used to pinch the elastic member in a state of elongation at a specific elongation rate; Regarding the elastic member, the elongation (conveying elongation) in the stretched state in the step of forming the fusion portion is made higher than the elongation (product elongation) of the stretchable sheet as a manufactured product in a natural state. ＜B2＞ The method for manufacturing a stretchable sheet as in the above <A1> or <B1>, wherein the elastic member is fixed to the two sheets only by friction with the two sheets. ＜B3＞ The method for manufacturing a stretchable sheet as in any one of the above <A1>, <B1> and <B2>, wherein the elasticity in the stretched state after the fusion portion forming step is performed and before the elastic member relaxation step is performed A gap is formed between the member and the pair of fusion portions disposed close to the elastic member. ＜B4＞ The method for manufacturing a stretchable sheet as described in any one of the above <A1> and <B1> to <B3>, wherein the length between the fusion part and the other fusion part constituting one of the fusion part pairs is relative to the length between the fusion part and the other fusion part. The ratio of the length in the width direction of the elastic member in the extended state in the fusion portion forming step is 1.3 or more and 3.5 or less. ＜B5＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B4>, wherein the length between the fusion part and the other fusion part constituting one of the fusion part pair The ratio of the length in the width direction of the elastic member in the extended state in the fusion portion forming step is 1.5 or more and 3.3 or less.

＜B6＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B5>, wherein the elongation rate of the elastic member in the elongation state in the step of forming the fusion portion is set to make the elastic The width direction length (diameter) of the member is less than 80% of the length between one of the fusion portions and the other fusion portion constituting the pair of fusion portions. ＜B7＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B6>, wherein the elongation rate of the elastic member in the elongation state in the step of forming the fusion portion is set to make the elastic The widthwise length (diameter) of the member relative to the length between the fusion portion and the other fusion portion constituting one of the fusion portion pairs is preferably 75% or less, more preferably 70% or less, and more preferably 30% or more, more preferably 35% or more, and still more preferably 40% or more. ＜B8＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B7>, wherein the length in the width direction of the elastic member in the extended state in the step of forming the fusion portion is 0.1 mm or more and 0.5 mm or less. ＜B9＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B8>, wherein the length in the width direction of the elastic member in the extended state in the step of forming the fusion portion is 0.2 mm or more and 0.4 mm or less.

＜B10＞ The method for manufacturing a stretchable sheet as in the above-mentioned <A1> and any one of <B1> to <B9>, wherein the length (D) between one of the fusion portions and the other fusion portion constituting the pair of fusion portions is preferred It is 0.12 mm or more, more preferably 0.2 mm or more, and is preferably 0.7 mm or less, and more preferably 0.6 mm or less. ＜B11＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B10>, wherein the widthwise length (diameter) of the elastic member in the relaxed state of the stretchable sheet (d2) The ratio (d2/D) with respect to the length (D) between one fusion portion and the other fusion portion constituting the aforementioned fusion portion pair is preferably 1.1 or more, more preferably 1.2 or more, and still more preferably 1.3 or more. ＜B12＞ The method for manufacturing a stretchable sheet as described in any one of <A1> and <B1> to <B11>, wherein in the step of forming the fusion portion, a plurality of pairs of the fusion portion are provided on the peripheral surface. On the peripheral surface of the roller (receiving roller 40) of the pair of convex portions (the first pair of convex portions 41), a laminate in which the elastic member in an extended state is arranged between the two sheets is formed, and the two sheets One of the sheets and the elastic member are housed in a concave portion (first concave portion 43) between a pair of convex portions (first convex portions 41a, 41b) constituting the pair of convex portions, and the laminated body is in this state. Among them, the two sheets are joined to each other to form a plurality of pairs of the aforementioned fusion portions, and The widthwise length (diameter) (a) of the elastic member in the extended state in the step of forming the fusion portion with respect to the depth (b) of the recessed portion, or between the fusion portion and the other fusion portion constituting the pair of the fusion portion The length (D) is preferably 1.1 times or more and 1.5 times or less, more preferably 1.2 times or more and 1.5 times or less, and still more preferably 1.3 times or more and 1.5 times or less. ＜B13＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B12>, wherein the elongation (conveying elongation) of the elastic member in the elongation state in the step of forming the fusion portion is equal to The ratio of the elongation (product elongation) of the elastic member when the above-mentioned stretchable sheet is in a natural state (non-elongated state) is based on the premise that the former> the latter. As the former/the latter, it is preferably 1.2 or more, more preferably 1.5 Above, and preferably 3.0 or less, more preferably 2.7 or less. ＜B14＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B13>, wherein the elongation (conveying elongation) of the elastic member in the elongation state in the step of forming the fusion portion is relatively It is preferably 200% or more, more preferably 220% or more, and still more preferably 240% or more, and more preferably 440% or less, more preferably 420% or less, and still more preferably 400% or less.

＜B15＞ The method for manufacturing a stretchable sheet as described in any one of <A1> and <B1> to <B14>, wherein the stretchable sheet has a first pair of fusion portions (15) and a second pair of fusion portions (16) As the fusion portion between the two sheets, the first fusion portion pair (15) is arranged close to the elastic member on both sides of the width direction (Y) via the elastic member, and the second fusion portion pair (16 ) Is arranged between a plurality of the elastic members intermittently arranged in the width direction and is not in contact with the elastic member, including a pair of fusion portions (second fusion portions 16a, 16b) arranged oppositely in the width direction And The ratio (L16/Le) of the length (L16) of the pair of the second fusion portion along the width direction to the interval (Le) between the two adjacent elastic members along the width direction (L16/Le) is preferably 0.25 or more , More preferably, it is 0.50 or more, More preferably, it is 0.70 or more. ＜B16＞ As in the method for manufacturing a stretchable sheet of any one of <A1> and <B1> to <B15>, the interval (Le) between the two adjacent elastic members 13 in the width direction is preferably 1 mm or more and 10 mm or less, more preferably 1 mm or more and 8 mm or less, and still more preferably 1 mm or more and 6 mm or less. ＜B17＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B16>, wherein the two adjacent pairs of the fusion portion (the first pair of fusion portions) that are adjacent to each other along the extension direction (X) 15. The interval (P1) between the second fusion portion pair 16) is preferably 6 mm or less, more preferably 5 mm or less, and still more preferably 3 mm or less. ＜B18＞ The method for manufacturing a stretchable sheet as in any one of the above <A1> and <B1> to <B17>, wherein the above-mentioned extending direction of the above-mentioned fusion part pair (the first fusion part pair 15 and the second fusion part pair 16) The length (width) of (X) is preferably 3 mm or less, more preferably 2 mm or less, and still more preferably 1 mm or less. ＜B19＞ The method for manufacturing a stretchable sheet as described in any one of the above <A1> and <B1> to <B18>, wherein in the step of forming the fusion portion, the peripheral surface of the roller (receiving roller 40) is formed on the The laminated body with the above-mentioned elastic member in the stretched state is arranged between the two sheets, and the roller is rotated to transport the laminated body to a specific pressing position. At the pressing position, the laminated body is sandwiched between the peripheral surface and the welding Ultrasonic vibration is applied between the vibration application surface of the front end of the head, thereby forming the above-mentioned fusion part pair, During the transportation of the laminate to the pressing position, the laminate is preheated by the heating mechanism built into the roller. ＜B20＞ A stretchable sheet manufactured by the manufacturing method of any one of the above-mentioned <A1> and <B1> to <B19>.

＜B21＞ An absorbent article having a longitudinal direction extending from the abdominal side of the wearer to the back side through the crotch portion and a transverse direction orthogonal to the longitudinal direction, and an absorbent body that absorbs and retains excrement, and Contains a stretchable sheet having stretchability in the above-mentioned transverse direction, The stretchable sheet includes two facing sheets, and an elastic member arranged between the two sheets and extending in the transverse direction, The fusion portions of the two sheets are arranged on both sides of the elastic member in the width direction via the elastic member in contact with the elastic member to form a fusion portion pair, and the fusion portion pair is intermittently arranged in the transverse direction. , The elastic member is compressed by a plurality of the fusion portions in a state of being stretched at a specific elongation in the lateral direction, There is an elastic member non-arrangement area where the elastic member is not arranged at the end of the transverse direction of the stretchable sheet, and The elastic member non-arrangement area includes a plurality of the fusion portion pairs intermittently arranged in the lateral direction, at least a lateral outermost fusion portion pair located at the outermost side of the lateral direction, and a pair of the lateral outermost fusion portion that is the outermost pair in the lateral direction. The fusion part is close to each other, and The end portions in the lateral direction of the elastic member are located in the pair of fusion portions. ＜B22＞ The absorbent article of the above-mentioned <B21>, wherein the lateral end of the elastic member overlaps with the pair of fusion portions (the first fusion portion pair 15) or is located at a distance of preferably within 5 mm from the pair of fusion portions, and more Preferably, the position is within 3 mm. ＜B23＞ The absorbent article of the above-mentioned <B21> or <B22>, which further includes an exterior body arranged on the non-skin facing surface side of the above-mentioned absorbent body, In each of the front body and the back body of the absorbent article, both side edges along the longitudinal direction of the outer body of the outer body are joined to each other to form a pair of side seals, a waist opening, and a pair of leg openings, and The exterior body includes the stretchable sheet, and the elastic member non-arrangement region includes the side seal portion. ＜B24＞ The absorbent article of the above-mentioned <B23>, wherein the length from the end of the outer body in the transverse direction (the side edge along the longitudinal direction) to the end of the elastic member in the transverse direction (the lack of elastic member 13 The length 13NL) is preferably 5% or more, more preferably 8% or more, and preferably 15% or less, and more preferably 12% or less relative to the full length of the lateral direction of the exterior body. ＜B25＞ The absorbent article of the above-mentioned <B23> or <B24>, wherein the length (elasticity) from the end of the outer body in the transverse direction (the side edge along the longitudinal direction) to the end of the elastic member in the transverse direction The missing length 13NL) of the member 13 is preferably 10 mm or more, more preferably 20 mm or more, and preferably 100 mm or less, more preferably 80 mm or less. ＜B26＞ The absorbent article according to any one of the above <B21> to <B25>, wherein there is no adhesive on the imaginary extension line of the elastic member in the elastic member non-arrangement area. [Industrial availability]

As described in detail above, according to the present invention, there is provided a stretchable sheet and an absorbent article in which the fixing of the elastic member is not easily released by stretching in a direction orthogonal to the extending direction of the elastic member of the stretchable sheet. According to the manufacturing method of the stretchable sheet of the present invention, the stretchable sheet provided with the elastic member arranged at a specific elongation rate can be stably manufactured regardless of the level of the elongation rate. According to the absorbent article of the present invention, the appearance can be improved.

1: diapers 1Z: diapers 2: Absorbent body 3: Front sheet 4: Back sheet 5: Absorber 6: Leak-proof flanging 7: Exterior body 7A: Ventral outer body 7C: dorsal exterior body 7S: Side edge 10: Stretchable sheet 10A: Stretchable sheet 10Z: stretchable sheet 11: The first sheet 11a: Original film 11E: Extension 12: The second sheet 12a: Original film 13: Elastic member 13a: winding body 13N: Non-configuration area of elastic member 14: Laminated body 15: The first fusion part pair 15a: The first fusion part 15b: The first fusion part 16: The second fusion part pair 16a: The second fusion part 16b: The second fusion part 17: Convex 20: Porosity change area 21: area 22: Cutting part 30: Ultrasonic processor 31: Welding head 31t: Vibration application surface 40: Undertake roll 40t: weekly face 41: Convex pair 41a: 1st convex part 41b: 1st convex part 42: Convex pair 42a: 2nd convex part 42b: 2nd convex part 43: The first recess 44: The second recess 60: Sheet for forming leak-proof flanging 61: Elastic member 100: Manufacturing device 101: Ultrasonic Processing Department 151a: Side edge 151b: side edge A: Ventral a: diameter b: depth c: width d2: width direction length B: Lower crotch C: dorsal part CD: direction D: interval L4: length L5: length L7: Length L16: length Le: interval LH: leg opening LO: leg opening M: Central MD: Mechanical travel direction P1: Pitch P2: Pitch P11: Symbol P12: Symbol R: Rotation direction S: side WH: Waist opening WO: Waist opening X: direction X1: portrait Y: direction Y1: horizontal Z: thickness direction

Fig. 1 is a partially broken plan view showing one embodiment of the stretchable sheet of the present invention. Fig. 2 is an enlarged plan view showing the main part of the stretchable sheet shown in Fig. 1. Fig. 3 is a cross-sectional view taken along the Y direction in which the main part of the stretchable sheet shown in Fig. 1 is enlarged and shown. Fig. 4 is a diagram showing the movement of the wearer when wearing a diaper using the stretchable sheet shown in Fig. 1 as an outer body. Fig. 5 is a cross-sectional view along the Y direction when the stretchable sheet shown in Fig. 1 is stretched in the direction. Fig. 6 is a cross-sectional view along the Y direction when the previous stretchable sheet is stretched in the direction. Fig. 7 is a perspective view showing a relaxed state of the stretchable sheet shown in Fig. 1. Fig. 8 is a microscope image of an example of the porosity change area of the present invention. Fig. 9 is a schematic diagram showing an apparatus that can be preferably used for manufacturing the stretchable sheet of the present invention. Fig. 10(a) is a plan view schematically showing a part of the peripheral surface of the receiving roller in the manufacturing apparatus shown in Fig. 9, and Fig. 10(b) is a perspective view of the peripheral surface. FIG. 11 is a cross-sectional view schematically showing a cross section of the first convex pair at the position indicated by the symbol P11 in FIG. 9 along the direction (CD) orthogonal to the traveling direction (MD (Machine Direction)). FIG. 12 is a cross-sectional view schematically showing a cross section along a direction (CD) orthogonal to the traveling direction (MD) at the position (ultrasonic processing position) indicated by the symbol P12 in FIG. 9. Fig. 13 is an enlarged cross-sectional view of a part of Fig. 12 (the first pair of convex portions and the vicinity thereof). 14(a) is a diagram schematically showing the state of the elastic member before the elastic member relaxation step is performed, and FIG. 14(b) is a diagram schematically showing the state of the elastic member after the elastic member relaxation step is performed. Fig. 15 is a perspective view schematically showing the natural state of the shorts-type disposable diaper as one embodiment of the absorbent article of the present invention. Fig. 16 is a schematic plan view of the skin facing surface side (front sheet side) of the diaper shown in Fig. 15 in an unfolded and stretched state. Fig. 17 is a plan view schematically showing an enlarged main part of the diaper shown in Fig. 15. Fig. 18 is a diagram corresponding to Fig. 17 of a disposable diaper outside the scope of the present invention.

11: The first sheet

12: The second sheet

13: Elastic member

15a: The first fusion part

15b: The first fusion part

20: Porosity change area

21: area

M: Central

S: side

Y: direction

Z: thickness direction

Claims (16)

A stretchable sheet having a first sheet including a fiber sheet, a second sheet disposed opposite to the first sheet and including a fiber sheet, and disposed between the two sheets in an extended state and An elastic member extending in one direction, and having elasticity along the extending direction of the elastic member, The first sheet and the second sheet are joined by a plurality of fusion portions which are located on both sides of the elastic member via the elastic member and are formed at intervals along the extending direction of the elastic member, The elastic member is located in a space formed by the fusion part, the first sheet and the second sheet located on both sides of the elastic member via the elastic member, and only by the surface of the elastic member and the first sheet The friction between the second sheet and the second sheet is fixed between the two sheets, When the stretchable sheet is observed in a cross-section in a direction orthogonal to the extension direction of the elastic member at the position where the fusion portion is formed, the length of the contact between the first sheet and the elastic member is longer than that of the second sheet and the elastic member. The connecting length of the components is long, When the stretchable sheet is viewed in a cross-section in a direction orthogonal to the extending direction of the elastic member at the position where the fusion portion is formed, the second sheet has a porosity change in the region overlapping with the elastic member in the thickness direction The void ratio change region is that the central portion in the above-mentioned orthogonal direction has a relatively higher void ratio between the constituent fibers than the two sides across the central portion, and In the above-mentioned porosity change region, a part of the constituent fibers loses the fiber shape and becomes a melted and solidified state, and the remaining part of the constituent fibers maintains the fiber shape. The stretchable sheet according to claim 1, wherein the first sheet and the second sheet are arranged between the adjacent elastic members and the adjacent fusion portions in the orthogonal direction. The other fusion part. The stretchable sheet according to claim 2, wherein the other fusion part has a lower joint strength than the fusion part. The stretchable sheet according to claim 2, wherein the length of the other fusion portion along the orthogonal direction is 0.2 mm or more and 5.0 mm or less. The stretchable sheet according to claim 1, wherein the length of the fusion portion along the extension direction of the elastic member is 0.1 mm or more and 3.0 mm or less. The stretchable sheet according to claim 1, wherein the distance between the fusion portions adjacent to each other in the extending direction of the elastic member is 1.0 mm or more and 6.0 mm or less. The stretchable sheet of claim 1, wherein the length between the outer ends of the fusion portion adjacent in the orthogonal direction is 1.0 mm or more and 10.0 mm or less. Such as the stretchable sheet of claim 1, wherein the distance between adjacent elastic members is 0.5 mm or more and 10.0 mm or less. Such as the stretchable sheet of claim 1, wherein the first sheet and the second sheet are laminated non-woven fabrics with spunbonded non-woven fabric layers. An absorbent article comprising an absorbent body and an outer body located on the non-skin facing side of the absorbent body, and The said exterior body contains the stretchable sheet material of Claim 1. A method for manufacturing a stretchable sheet, which is the method for manufacturing a stretchable sheet according to any one of claims 1 to 9, the stretchable sheet is The fusion portion of the two sheets including the first sheet and the second sheet is arranged close to the elastic member on both sides in the width direction of the elastic member via the elastic member to form a fusion portion pair, the fusion portion A plurality of pieces are intermittently arranged in the extending direction of the elastic member, The elastic member is compressed by a plurality of the fusion portions in a state of being stretched at a specific elongation in the extension direction of the elastic member, and The manufacturing method of the stretchable sheet includes: The step of forming a fusion part is to arrange an elastic member in a state of being stretched in one direction between two sheets, and the two sheets are placed at a plurality of positions on both sides of the elastic member in the width direction through the elastic member in the stretched state. The sheets are joined to each other to form a plurality of pairs of fusion portions; and The elastic member relaxation step is to release the stretched state of the elastic member to relax the elastic member, and by increasing the width direction length of the elastic member accompanying the relaxation, the elastic member is sandwiched between the fusion portion pair The adhesion between the part and the fusion portion pair is improved compared to before relaxation, whereby the fusion portion pair is used to pinch the elastic member in a state of being stretched at a specific elongation; and Regarding the elastic member, the elongation rate in the extended state in the step of forming the fusion portion is made higher than the elongation rate in the natural state of the stretchable sheet as a manufactured product. The method for manufacturing a stretchable sheet according to claim 11, wherein the length between the fusion portion and the other fusion portion constituting one of the fusion portion pairs is relative to the stretched state of the elastic member in the fusion portion forming step The ratio of the length in the width direction is 1.3 or more and 3.5 or less. The method for manufacturing a stretchable sheet according to claim 11, wherein the elongation rate of the elastic member in the extended state in the step of forming the fusion portion is set such that the width direction length of the elastic member is less than that of the pair of the fusion portion 80% of the length between one said fusion part and the other said fusion part. The method for manufacturing a stretchable sheet according to claim 11, wherein the length in the width direction of the elastic member in the extended state in the step of forming the fusion portion is 0.1 mm or more and 0.5 mm or less. A method for manufacturing a stretchable sheet, which is a method for manufacturing a stretchable sheet as follows. The stretchable sheet is an elastic member extending in one direction between two opposing sheets, and in the extending direction of the elastic member Flexible, The fusion portions of the two sheets of each other are arranged close to the elastic member on both sides of the elastic member in the width direction via the elastic member to form a fusion portion pair, and the fusion portion pair is intermittently arranged in the extending direction of the elastic member Plural, The elastic member is compressed by a plurality of the fusion portions in a state of being stretched at a specific elongation in the extension direction of the elastic member, and The manufacturing method of the stretchable sheet includes: The step of forming a fusion part is to arrange an elastic member in a state of being stretched in one direction between two sheets, and the two sheets are placed at a plurality of positions on both sides of the elastic member in the width direction through the elastic member in the stretched state. The sheets are joined to each other to form a plurality of pairs of fusion portions; and The elastic member relaxation step is to release the stretched state of the elastic member to relax the elastic member, and by increasing the width direction length of the elastic member accompanying the relaxation, the elastic member is sandwiched between the fusion portion pair The adhesion between the part and the fusion portion pair is improved compared to before relaxation, whereby the fusion portion pair is used to pinch the elastic member in a state of being stretched at a specific elongation; and Regarding the elastic member, the elongation rate in the extended state in the step of forming the fusion portion is made higher than the elongation rate in the natural state of the stretchable sheet as a manufactured product. An absorbent article having a longitudinal direction extending from the abdominal side of the wearer to the back side through the crotch portion and a transverse direction orthogonal to the longitudinal direction, and an absorbent body that absorbs and retains excrement, and Contains a stretchable sheet having stretchability in the above-mentioned transverse direction, The stretchable sheet includes two facing sheets, and an elastic member arranged between the two sheets and extending in the transverse direction, The fusion portions of the two sheets are arranged on both sides of the elastic member in the width direction via the elastic member in contact with the elastic member to form a fusion portion pair, and the fusion portion pair is intermittently arranged in the transverse direction. , The elastic member is compressed by a plurality of the fusion portions in a state of being stretched at a specific elongation in the lateral direction, There is an elastic member non-arrangement area where the elastic member is not arranged at the end of the transverse direction of the stretchable sheet, and The elastic member non-arrangement area includes a plurality of the fusion portion pairs intermittently arranged in the lateral direction, at least a lateral outermost fusion portion pair located at the outermost side of the lateral direction, and a pair of the lateral outermost fusion portion that is the outermost pair in the lateral direction. The fusion part is close to each other, and The end portions in the lateral direction of the elastic member are located in the pair of fusion portions.

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