TW202103661A - Expandable/contractible sheet, and absorbent article provided with expandable/contractible sheet - Google Patents

Abstract

The present invention has a first sheet (11), a second sheet (12), and a plurality of elastic members (13) that are disposed in a stretched state between the two sheets (11, 12) and that extend in one direction. The first sheet (11) and the second sheet (12) are joined by a plurality of fusion-bonded parts (15) that are positioned so as to sandwich the elastic members (13) on both sides and that are formed with gaps therebetween along the direction in which the elastic members (13) extend. The elastic members (13) are secured only by friction with the two sheets (11, 12) in a space demarcated by the fusion-bonded parts (15), the first sheet (11), and the second sheet (12). The second sheet (12) has a low-porosity region (20) on the thickness-direction inner side along the entirety of the region between the fusion-bonded parts. In the low-porosity region (20), some of constituent fibers are melted and solidified so that the fibrous shape thereof is lost, and the fibrous shape of the remaining constituent fibers is maintained.

Description

Stretchable sheet and absorbent article provided with the stretchable sheet

The present invention relates to a stretchable sheet. In addition, the present invention relates to an absorbent article provided with 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 sheet in which a plurality of elastic elastic members arranged in parallel are sandwiched between an inner sheet and an outer sheet, and the inner sheet and the outer sheet are intermittently welded , Thereby fixing the elastic telescopic member. The elastic elastic member is arranged in a cross-sectional space enclosed by the welded part of the inner sheet and the outer sheet near the two sides in the diameter direction, and the outer surface of the elastic elastic member and the sheet forming the closed space The friction is fixed.

Patent Document 2 describes a composite sheet in which a hydrophobic non-woven fabric and a hydrophilic non-woven fabric are joined with an elastic member interposed therebetween. In the two non-woven fabrics, at least the hydrophilic non-woven fabric forms concavities and convexities. The non-woven fabric includes a protrusion that has a higher fiber density than other parts and protrudes from the hydrophobic non-woven fabric. At the protrusion, the hydrophobic non-woven fabric and the hydrophilic non-woven fabric are directly connected to each other.

In addition to these techniques, the applicant first proposed a sheet material, which includes a hydrophobic sheet material with a plurality of recesses, a hydrophilic sheet material, and a plurality of sheets arranged in an elongated state between the two sheets. The elastic member and the hydrophobic sheet have a fusion part at the top of the recess, and the thickness of the fusion part is within a specific range (Patent Document 3). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-104853 [Patent Document 2] Japanese Patent Laid-Open No. 2017-12319 [Patent Document 3] Japanese Patent Laid-Open No. 2017-113188

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 structure in the thickness direction of the entire area between the fusion portions The void ratio between the fibers is relatively lower than the low void ratio regions in other regions. Preferably, in the above-mentioned low porosity region, a part of the constituent fibers loses the fiber form and becomes a melted and solidified state, and the remaining part of the constituent fibers maintains the fiber form.

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. The exterior body includes the stretchable sheet. It is preferable that the said stretchable sheet is arrange|positioned so that the 1st sheet|seat of this stretchable sheet may become a skin facing surface side.

From the viewpoint of reducing the discomfort caused by sweat or the viewpoint of preventing the generation of eczema, heat rash, rash, etc., the sheet used for the absorbent article desirably has an excellent effect of removing the absorbed sweat from the skin. The stretchable sheet described in Patent Document 1 is formed by joining two sheets to each other without using an adhesive. The stretchable sheet of such a structure may have sweat remaining on the skin contact surface side, and sometimes sweat may remain. The stretchable sheet may contact the skin and cause discomfort. Patent Documents 2 and 3 disclose a stretchable sheet formed by joining two sheets through an adhesive, but they do not disclose a stretchable sheet formed by joining without an adhesive and having the effect of keeping sweat away from the skin .

The present invention is related to providing a stretchable sheet that can eliminate the above-mentioned disadvantages of the prior art, 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. When the first sheet 11 is a hydrophilic sheet, the following various advantages are produced. 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 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 nonwoven 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 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. When the above-mentioned first sheet 11 is a hydrophilic fiber sheet, the second sheet 12 is preferably 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 this 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|melting part 16 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 folds can be formed on each surface of the stretchable sheet 10.

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, and is fixed to the two by friction with the first sheet 11 and the second sheet 12 only. Between sheets 11 and 12. 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. In detail, 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 of the elastic member 13 in the other first fusion portion 15b are made The interval between the side edges 151b, that is, the interval D of the first fusion portion, is narrower than the diameter d1 of the elastic member 13 in the maximum elongation state of the stretchable sheet 10, and is only limited by a pair of first fusion portions 15a, 15b. The friction on the surface of the elastic member 13 generated by the pressure in the above-mentioned space fixes the elastic member 13 between the first and second sheets 11 and 12. 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 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 above. 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, 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 perpendicular to the extension direction of the elastic member 13 at the positions where the fusion portions 15a, 15b are 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 halved in the thickness direction Z in the cross-sectional view, becomes an asymmetrical shape between the second sheet 12 side and the first sheet 11 side of the elastic member 13 (see FIG. 3) . In other words, when viewed in this cross-section, 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 . Regarding the second sheet 12 side of the elastic member 13, the portion between the first fusion portion 15a, 15b when viewed in the 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 Compared to become a roughly flat part.

Furthermore, as shown in FIG. 3, in the stretchable sheet 10, the second sheet 12 has low voids in the thickness direction Z in the entire region between the fusion portions 15a and 15b, which constitutes the inter-fiber void ratio relatively lower than other regions. Rate area 20. The other region refers to a region other than the low porosity region 20 in the second sheet 12, that is, a region other than the region overlapping with the elastic member 13 in the thickness direction Z, and a region composed of fibers. Therefore, the regions where the fibers melt and lose their original fiber state, that is, the first fusion portion 15a, 15b and the second fusion portion 16 do not match the other regions. The low porosity region 20 only needs to have a porosity in the entire thickness direction that is lower than the porosity in the entire thickness direction of other regions. On the other hand, the following morphology is excluded from the low porosity region 20, that is, on the surface side of either side of the thickness direction, the fiber melts and the porosity decreases, but in the thickness direction, the fiber maintains the fiber shape and the porosity decreases high. Inside the thickness direction of the low-porosity region 20, a portion with a lower porosity than the other regions described above may exist continuously in the Y direction, or may exist intermittently in this direction. The stretchable sheet has a low porosity area 20 in the second sheet 12. The low porosity region 20 is formed on the second sheet 12 located between a 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 low-porosity region 20 has a lower porosity than other regions, and the low-porosity region 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 in which the void ratio between the constituent fibers in the thickness direction is lower than that of the regions other than between the fusion portions 15a and 15b. The above-mentioned region 21 only needs to have a porosity in the entire thickness direction that is lower than the porosity in the entire thickness direction of the other regions in the first sheet 11. The so-called other area refers to the area other than the area 21 with the lower porosity in the first sheet 11, that is, the area other than the area overlapping with the elastic member 13 in the thickness direction Z, and the first sheet 11 and the second sheet 11 The sheet 12 is not joined and is an area composed of fibers. Therefore, the regions where the fibers melt and lose their original fiber state, that is, the first fusion portion 15a, 15b and the second fusion portion 16 do not match the other regions. The above-mentioned area 21 may have a porosity lower than other areas in the first sheet 11 throughout its entire thickness direction, or it may have a porosity inside the thickness direction lower than other areas in the first sheet 11 and The porosity on the surface side in the thickness direction is higher than the inside. Hereinafter, a region having the above-mentioned porosity and overlapping with the elastic member 13 in the thickness direction Z, and a region composed of a sheet arranged opposite to the low porosity region 20 with the elastic member 13 interposed therebetween, is also referred to as a second low void. Rate 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 substantially flat portion of the elastic member 13. Thereby, at the positions where the fusion portions 15a and 15b are 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 the present 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 low porosity region 20 has a shape following the shape of the elastic member 13. Specifically, the low-porosity region 20 is in close contact with the surface of the elastic member 13 that faces the low-porosity region 20, and has a shape that follows the shape of the surface.

In the cross-sectional observation of the above-mentioned stretchable sheet 10 along the Y direction, when the low porosity region 20 is viewed along the Y direction, the thickness of the low porosity region 20 is constant. "Fixed thickness" means that the difference between the maximum thickness and the minimum thickness of the low-porosity region 20 is 5 μm or less. The maximum thickness of the low porosity region 20 is measured using image data obtained by magnifying and observing the cross-section of the sample in the following [Method for Measuring Porosity].

In the low porosity region 20, 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. That is, the low porosity region 20 is a region where fibers having a melt-solidified portion and fibers without a melt-solidified portion are mixed. The second low porosity region 21 may also include fibers having melted and solidified portions. The amount of fibers having a melt-solidified portion in the second low-porosity region 21 is preferably 0-20% of the fibers existing in the second low-porosity region 21. The amount of fibers with 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 can be preferably used to form an outer casing of an absorbent article. From the viewpoint of contact with the wearer’s skin and easily absorb sweat, the stretchable sheet 10 shown in Fig. 3 is preferably as shown in Figs. 4(a) to (c), and a hydrophilic sheet is used as the first One sheet 11 is used in a state where the first sheet 11 is on the side facing the skin. In this state of use, at the position where the stretchable sheet 10 overlaps the elastic member 13 in the thickness direction Z, the sweat E in contact with the first hydrophilic sheet 11 is attracted in the thickness direction Z , And move toward the elastic member 13 side of the first sheet 11 [refer to Fig. 4(a)]. Since the elastic member 13 and the first sheet 11 are in close contact with each other, capillary force acts between them. This causes sweat E to reach between the elastic member 13 and the first sheet 11 [see FIG. 4(b)]. As described above, between the pair of first fusion portions 15a, 15b, the elastic member 13 is pinched by the first sheet 11 and the second sheet 12 and closely adhered to each other. Therefore, the sweat E runs along the surface of the elastic member 13 and the first sheet. The interface of 1 sheet 11 spreads well. In particular, the low porosity region 20 of the present embodiment constitutes a lower porosity between the fibers than other regions, and therefore, a larger capillary force acts. Thereby, the diffused sweat E is easily attracted to the low porosity area 20 [refer to FIG. 4(c)].

When the second sheet 12 is used with the skin facing side, the void ratio between the constituent fibers of the low-porosity region 20 is lower than that of the other regions in the second sheet 12, so the second sheet 12 The sweat E absorbed in the plane direction of the sheet 12 moves to the low porosity area 20. Thereby, the sweat E absorbed in a wide range can be concentrated to the low porosity area 20, and the contact area between the part containing the sweat E and the skin S can be reduced. In addition, the capillary force at the interface between the low porosity region and the elastic member 13 is greater than that of the interface between the low porosity region 20 and the skin S. The sweat E reaching the low-porosity region 20 due to the difference in capillary force is held between the low-porosity region 20 and the surface of the elastic member 13 and is not easily returned to the skin side (see FIG. 5). As a result, the absorbed sweat E can be separated from the skin S, and the discomfort caused by the sweat E can be reduced.

As described above, the absorbed sweat E can be separated from the skin S in the thickness direction Z of the stretchable sheet 10, and the absorbed sweat can be prevented from contacting the skin S. As a result, the discomfort caused by sweat can be reduced. In addition, by moving the sweat E away from the skin S, the moisture caused by the sweat E can be prevented from filling the inside of the absorbent article, and the sweat can be effectively evaporated to the outside of the absorbent article.

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 for forming an outer surface of an absorbent article, and the stretchable sheet is arranged such that the second sheet 12 faces the wearer's skin, it can be The low porosity 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 from the center of the stretched direction of the elastic member in the stretchable sheet and fix it by a pair of first fusion parts 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 and second sheets, and the elastic member and the first and second sheets are not fused with each other. Therefore, when the sample is cut out, sometimes The elastic member fell off from 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 peripheral surface side of the fiber without observing the cross section of the fiber, all parts other than the cross section are recognized as voids. Then, the outer edge of the second sheet between the welded parts in the observation field is drawn along the outline of the white part described above, and the outline of the low void content area is specified. The boundary between the low porosity region and the fusion part is sometimes not clear because the melted and solidified part in the fiber is integrated between the fibers. The boundary is specified by the following method. First, the following fibers are identified, that is, the cross-sectional shape of a fiber having a fusion-solidified portion, and more than half of the contour of the contour perimeter of the fiber cross-section can be recognized. Then, a plurality of continuous portions of the above-mentioned fibers are identified along the thickness direction Z of the stretchable sheet, and the outline of the fibers is traced across the plurality of fibers along the thickness direction, thereby identifying the boundary. Using the image processing software described above, measure the area of the specified low porosity area, set it as the area of the low porosity area (A ₁ ), and measure the area of the portion identified as a void in the area enclosed by the above outline , Set it as the void area (A ₂ ) in the low void ratio region. Then, according to the following formula [1], the porosity (GR) of the low porosity region is calculated. GR(%)=(A ₂ /A ₁ )×100...Equation [1] GR: Porosity of low porosity region A ₁ : Area of low porosity region A ₂ : Porosity area of low porosity region The measurement is performed at any three locations where a pair of first fusion portions are formed, and the average value is set as the porosity of the low porosity region.

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 part existing in the contour of the low porosity region 20 is larger than the cross-sectional area of the fiber observed in other regions. When the contour of the melted and solidified part of the fiber is not clear, the area of the molten and solidified part is measured (B2) and the average cross-sectional area per fiber (B1) observed in other regions. According to the following formula [2], calculate the number of fibers per melted and solidified part (B), and increase it to The total number of fibers with melted and solidified parts. The average cross-sectional area (B1) of each fiber is set to the average value of 3 fibers arbitrarily selected in other regions. B=B2/B1...〔2〕 B: The number of fibers in each part of melting and solidification B1: The average cross-sectional area of each fiber B2: The area of the melted and solidified part The amount of fibers having melted and solidified portions is measured at any three locations in the stretchable sheet where a pair of first fusion portions are formed, and set as the average value of the same.

The porosity of the second low porosity region and other regions can also be measured in the same manner as the above method. The porosity of the second low porosity region is performed after identifying the contour of the second low porosity region from the first sheet in the image of the observation field described above. The porosity of the other regions is performed by magnifying and observing 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 in the region other than the fusion part.

The state of the constituent fibers in the low porosity region 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 region overlapping with the elastic member satisfies 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 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. 7, for example. The cavity in the center of the microscope image shown in FIG. 7 is the part where the elastic member is arranged, and the film-like part at the position where the cavity is interposed is the first fusion part. In the microscope image shown in Fig. 7, the low porosity area is represented by a frame line. The melt-solidified part of the fiber in the low porosity region is shown in Fig. 7, which is a part where a part of the fiber is integrated with other fibers. Since the fibers are entangled with each other, the whole part becomes a block. In addition, in FIG. 7, the portion opposed to the low-porosity region via the cavity is the second low-porosity region. In this figure, the second low porosity region has fewer melted and solidified parts, so the fibers are dispersed without being integrated.

The first sheet material 11 preferably has a second low porosity region 21. With this structure, the above-mentioned effect of keeping sweat E away from skin S can be exerted. Specifically, the sweat E absorbed in a wide range can be concentrated in the second low porosity region 21, and the contact area between the part containing the sweat E and the skin S can be reduced. In addition, compared with the interface between the second low porosity region 21 and the skin S, the capillary force at the interface between the second low porosity region and the elastic member 13 is higher, and therefore, the sweat E reaching the second low porosity region It is held between the second low porosity region and the surface of the elastic member 13 and is not easily returned to the skin side. As a result, the absorbed sweat E can be separated from the skin S, and the discomfort caused by the sweat E can be reduced.

From the viewpoint of further enhancing the effect of separating sweat E from the skin between the first fusion portions 15a and 15b of the first sheet material 11, the first sheet material 11 is preferably between the pair of first fusion portions 15a and 15b There are a plurality of regions with different void ratios. The region between the pair of first fusion portions 15a and 15b in the first sheet 11 is preferably a plurality of regions with different porosity, and the region with a relatively low porosity has the following constitutions (c1) to (c3) Any one or a combination of these two or more. Composition (c1): In the area between one pair of first fusion portions 15a and 15b in the first sheet material 11, a portion in contact with the skin is formed. Composition (c2): Located at the center in the Y direction of the region between one pair of first fusion portions 15a, 15b in the first sheet material 11. Composition (c3): The length in the Y direction is the same as or longer than the length in the Y direction of the region with a relatively high porosity among a plurality of regions where the porosity is different from each other. From the viewpoint of further improving the above effect, with respect to the above configuration (c3), the length in the Y direction of the region with relatively low porosity is longer than the length in the Y direction of the region with relatively high porosity. It is preferably 100% or more, more preferably 120% or more, more preferably 200% or less, and more preferably 150% or less.

The above-mentioned relatively high porosity region and the above-mentioned relatively low porosity region between the first fusion portions 15a and 15b of the first sheet 11 are identified by the following method. First, the area where the first sheet 11 and the elastic member 13 overlap is divided into 10 equal parts in the Y direction. For each of these areas, the area of the entire area and the area of the gap are measured using the above-mentioned image processing software. . Then, by dividing the void area by the area of the entire region, the void ratio of each of the 10 regions is calculated. Then, the 10 areas are divided into 2 groups so that the difference in porosity becomes 30% or more. The area belonging to the group with the higher porosity among the two groups is set as the "area with relatively high porosity", and the area belonging to the group with the lower porosity is set as the "area with relatively low porosity".

As described above, the first and second sheets 11 and 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 stretchable sheet 10 in the X direction becomes narrow. The first sheet 11, which has lost its place due to the narrowing of the width, protrudes away from the elastic member 13 with the second fusion part 16 as the starting point of bending as shown in FIG. 6. 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. With the convex portion 17, the contact area between the stretchable sheet and the skin becomes smaller, and the ratio of the sweat diffusion area to the contact area becomes larger, and therefore, the sweat transpiration effect is further improved. The sweat diffusion area is the area of the stretchable sheet that is wetted by sweat, and the sweat moves and spreads between the low porosity region 20 or the low porosity region 20 and the elastic member 13.

In this embodiment, the first and second sheets 11 and 12 are protruded so as to be separated from each other in the thickness direction as shown in FIG. 6 with the second fusion part 16 as the starting point of bending. 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|seat 11 and the 2nd sheet|seat 12, respectively. With this configuration, the above-mentioned transpiration effect is further improved, and the contact area between the stretchable sheet 10 wetted with sweat and the skin is reduced, and therefore, the wearing feeling of the absorbent article using the sheet is further improved. The above-mentioned convex portion 17 is a part of the stretchable sheet 10 that forms the following folds, and follows the shape of the elastic member 13 at the position overlapping the elastic member 13 with the first sheet 11 and the second sheet 12 The part of the different part.

As shown in FIG. 6, the convex portion 17 extends continuously in the Y direction. On each surface of the stretchable sheet 10, a plurality of folds are formed by the above-mentioned convex portion 17. The stretchable sheet 10 in the state shown in FIG. 6 exhibits a soft texture and an excellent appearance due to the above-mentioned folds.

From the viewpoint of further improving the effect of sweat evaporation, when the interval between two elastic members 13 adjacent in the Y direction is set to Le (refer to FIG. 1), the second fusion portion 16 along the Y direction The ratio of the length L16 (refer to 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.

From the same viewpoint as described above, the interval Le between two elastic members 13 adjacent to each other in 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 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 more preferably 1 mm or more and 6 mm or less.

From the same viewpoint as above, when the interval between two fusion portions adjacent in the X direction is Lf (refer to Fig. 1), the value of Lf is preferably 6 mm or less, and more preferably 5 mm or less , More preferably 3 mm or less. The lower limit of Lf is not particularly limited, and the smaller the value, the larger the diffusion area of sweat, which is better.

Furthermore, from the same viewpoint as the above, the width of the first fusion portion 15 and the second fusion portion 16, that is, the length in the X direction is preferably 3 mm or less independently of each other, more preferably 2 mm or less, more preferably It is less than 1 mm. 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 and second sheets 11 and 12, for example, hot-air nonwoven fabrics, hot rolled nonwoven fabrics, spunlace nonwoven fabrics, spunbonded nonwoven fabrics, meltblown nonwoven fabrics and other nonwoven fabrics obtained by various manufacturing methods can be used, and two or more of these can be used. The layered body, etc. formed by the integration of layers. 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.

As described above, as the first and second sheets 11 and 12, it is preferable to use non-woven fabrics. 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 overlapped part were nailed with a stapler or the like, and this was used as a measurement sample. Use the compression test mode of the TENSILON universal testing device for the measurement sample 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 perpendicular 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 and second sheets 11 and 12 are not limited to two separate sheets. One sheet may be bent to form two opposing faces, and the part that constitutes one face is made into one sheet. The part on the other side is set as another sheet. When the first and second sheets 11 and 12 are composed of one sheet, the one sheet is preferably a hydrophilic fiber sheet.

As a forming material of the elastic member 13, various well-known elastic materials used in absorbent articles such as disposable diapers and menstrual sanitary 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 urethane etc., those having a rectangular, square, circular, polygonal or other linear or string-like shape (flat tape etc.) in cross section, or a multifilament-like linear shape, etc. can be used.

Next, a preferred method of manufacturing the stretchable sheet 10 shown in FIGS. 1 to 6 will be described with reference to FIG. 8. In this figure, an apparatus which can be preferably used for manufacturing the stretchable sheet 10 is shown. The device 100 shown in the figure includes an ultrasonic fusion unit 30. The ultrasonic fusion part 30 includes an ultrasonic vibration welding head 31 and a receiving roller 32 arranged at a position facing the front end of the welding head 31. The welding head 31 is made of metal such as aluminum alloy or titanium alloy, and is designed to resonate in the frequency band used. The welding head 31 is connected to an horn (not shown), and the ultrasonic vibration transmitted from the horn to the welding head 31 is amplified or attenuated inside the welding head 31 and applied to the welding object.

The receiving roller 32 is designed to adjust the temperature of the receiving roller 32 so that the first sheet 11 and the second sheet 12 that are in contact with the receiving roller 32 can be heated. That is, by winding around the receiving roller 32, the first sheet 11 and the second sheet 12 can be heated. The receiving roller 32 can adjust the temperature of the receiving roller 32 by, for example, having a heater for heating the receiving roller 32 and a temperature sensor for measuring the temperature of the receiving roller 32 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.

In FIG. 9, the main part of the ultrasonic fusion part 30 in FIG. 8 is enlarged and shown. The ultrasonic fusion part 30 is provided with the receiving roller 32 which forms the contact part 40 and 41 which formed the convex part on the peripheral surface, and the welding head 31 which can abut against the convex part. The Y direction shown in FIG. 9 is the width direction (axial direction) of the receiving roller 32, and this direction coincides 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 32 in the ultrasonic fusion portion 30, a pair of convex portions are arranged along the axial direction. A recess 42 is formed between the pair of convex portions. The pair of convex portions are also collectively referred to as the first contact portion 40. The receiving roller 32 is intermittently provided with the 1st contact part 40 along the rotation direction R (refer FIG. 8) of a roller. In addition, on the peripheral surface of the receiving roller 32, a plurality of second contact portions 41 are intermittently provided along the rotation direction R of the receiving roller 32. The first abutting portion 40 and the second abutting portion 41 form convex portions protruding toward the welding head 31 on the peripheral surface of the receiving roller. That is, the first contact portion 40 and the second contact portion 41 are located on the side close to the horn 31. In the receiving roller 32, the first abutting portions 40 are located on the same line in the rotation direction R, and the second abutting portions 41 are located on the same line in the rotation direction R. In the receiving roller 32 in the present embodiment, the first abutting portions 40 and the two second abutting portions 41 are alternately arranged in the width direction. On the other hand, in the welding head 31, the surface which has the part contact|abutted to the 1st contact part 40 and the 2nd contact part 41 becomes a flat surface without unevenness|corrugation.

As shown in FIG. 9 and FIG. 10, in the first contact portion 40, a recess 42 is provided in the Y direction, that is, at a substantially central portion in the roll width direction. The recess 42 has a rectangular shape when viewed in cross section along the width direction of the receiving roller 32. The recess 42 has a volume for accommodating at least a part of the elastic member 13 in an extended state. In other words, the concave portion 42 has a volume such that the elastic member 13 can partially protrude from the upper surface of the first abutting portion 40 in a state in which the elastic member 13 is housed in the concave portion 42. The opening width of the recessed portion 42 along the Y direction is approximately equivalent to the first fusion portion interval D in the target stretchable sheet 10 (refer to FIG. 2).

In this manufacturing method, the first sheet 11, the second sheet 12, and a plurality of elastic members 13 arranged between the two sheets 11 and 12 in an extended state are used. Returning to FIG. 8, the first sheet 11 wound from the original sheet 11 a of the first sheet 11 is wound on the peripheral surface of the receiving roller 32 and transported. In the state where the first sheet 11 is wound around the peripheral surface of the receiving roller 32, the plurality of elastic members 13 respectively wound out from the winding body 13a are arranged on the surface of the first sheet 11 in an extended state. The elastic member 13 is transported in a state of being partially housed in the recess 42 of the first contact portion 40 provided on the peripheral surface of the receiving roller 32. At this point in time, the first sheet 11 is first stored in the recess 42 (refer to FIG. 9).

When a part of the recess 42 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 recess 42 The width of the opening in 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.

After the elastic member 13 is accommodated in the recess 42, the second sheet 12 rolled out from the original sheet 12 a of the second sheet 12 is supplied to the peripheral surface of the receiving roller 32. In this way, a laminate in which the stretched elastic member 13 is arranged between the first sheet 11 and the second sheet 12 is prepared. That is, the above-mentioned laminated system is supplied so that the elastic member 13 in the laminated body passes through the recessed portion 42 in a state where the convex portions 40 and 41 of the receiving roller 32 and the joining portion of the sheet member face each other. In the laminate, the first sheet 11 and the second sheet 12 are preheated by being wound around the receiving roller 32 as described above. Ultrasonic vibration is applied to the laminate by the welding head 31 (refer to FIGS. 9 and 10). At this time, the laminated body 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 runs along The roughly flat part.

The ultrasonic welding part 30 fuses the first sheet 11 and the second sheet 12 in the laminate 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 16 described above are formed. As shown in FIG. 9, on the peripheral surface of the receiving roller 32, the first abutting portion 40 and the second abutting portion 41 protrude more than the other portions, and are located on the side close to the welding head 31, so they are located at the first abutting portion 40 The first sheet 11 and the second sheet 12 on the second abutting portion 41 are fused to form a first fusion portion 15 and a second fusion portion 16 that join these sheets. At this time, the elastic member 13 is partially housed in the recess 42 and the elastic member 13 is not fused with the first sheet 11 and the second sheet 12, and maintains a non-joined state. By the fusion performed by the ultrasonic fusion portion 30 described above, a part of the fibers constituting the first fusion portion 15a, 15b is melted in one of the second sheets 12 to form the low porosity region 20, and the first sheet 11 A second low porosity region 21 is formed between the pair of first fusion portions 15a and 15b. By applying ultrasonic waves in this way, 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. As shown in FIG. 2, the elastic member 13 having a larger diameter becomes the interval between the two first fusion portions 15a and 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. 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. Thereby, between a pair of 1st fusion|fusion part 15a, 15b, the shape of the 2nd sheet|seat 12 side of the elastic member 13 with an enlarged diameter, and the shape of the 2nd sheet|seat 12 are maintained substantially flat. The extent of elongation of the elastic member 13 and the opening width of the recess 42 along the Y direction at the time of manufacturing the stretchable sheet 10 may be appropriately set according to the desired stretched state of the stretchable sheet 10.

The first and second sheets 11 and 12 and the elastic member 13 constituting the stretchable sheet 10 or the degree of extension of the elastic member 13 when housed in the recess 42 is such that the stretchable sheet 10 has the desired stretchability (stretching Rate) or the desired way of folds. In this manufacturing method, for example, the degree of elongation of the elastic member 13 can be adjusted by appropriately adjusting the depth or width of the recess 42 (first fusion portion interval D), etc. From the viewpoint of easily forming the low porosity region 20, in the present manufacturing method, it is preferable to use the first sheet in the laminated body when the laminated body is supplied to the ultrasonic fusion part 30 as the fusing device. The depth or width of the recess 42 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 recess 42 is preferably within the following range. The width c of the recess 42 (refer to FIG. 10) is based on the premise that the elastic member 13 and the first sheet 11 are housed in the recess 42, and is preferably the diameter a of the elastic member 13 in the extended state (refer to FIG. 10) More than 1.0 times and 2.0 times or less. The diameter a (refer to FIG. 10) of the elastic member 13 in the stretched state is the depth b (refer to FIG. 10) of the recess 42, which 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 More than 1.3 times and less than 1.5 times.

From the viewpoint of easy formation of the low porosity 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 3 N/mm or more, and more Preferably it is 3.2 N/mm or more, more preferably 4 N/mm or less, more preferably 3.8 N/mm or less, preferably 3 N/mm or more and 4 N/mm or less, more preferably 3.2 N/mm or more 3.8 N/mm or less.

As described above, in the present manufacturing method, after the second sheet 12 is preheated, ultrasonic vibration is applied to the second sheet 12. The inventors found that by preheating the second sheet 12 before ultrasonic vibration is applied to the second sheet 12, the low porosity 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, and therefore, it is possible to perform sealing to the extent that the elastic member 13 can be fixed from both sides by weaker ultrasonic vibration. 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 32 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 obtained in this way can be used, for example, 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. In the case where the exterior body contains the stretchable sheet of the present invention, from the viewpoint of making the above-mentioned effect of removing sweat from the skin more surely exerted, the stretchable sheet is preferably one in the stretchable sheet The first sheet 11 is arranged in such a way that it becomes the side facing the skin, and is more preferably arranged at a position that can be in contact with the wearer's skin. The "skin facing surface" refers to the surface of the absorbent article or its constituent members (for example, absorbent body) that faces the wearer's skin when the absorbent article is worn, that is, the side relatively close to the wearer's skin. The absorbent article may further include various members corresponding to its specific use. Such components are well known to the industry.

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

In addition, in the above embodiment, the case where the first sheet 11 is a hydrophilic sheet and the second sheet 12 is a hydrophobic sheet has been mainly described, but the present invention is not limited to this, and may be the first sheet. The material 11 is a hydrophobic sheet, and the second sheet 12 is a hydrophilic sheet. Alternatively, both the first sheet 11 and the second sheet 12 may be hydrophilic sheets, or both may be hydrophobic sheets. 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 above-mentioned embodiment, in the stretchable sheet 10, the first sheet 11 has the second low porosity region 21, but the second low porosity region 21 may not be provided. For example, the first sheet 11 may be a region facing the second sheet 12 with the elastic member 13 interposed therebetween, which has the same porosity as the other regions described above.

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 formation position of the fusion portion, the second sheet has the inter-fiber composition in the entire area between the fusion portions in the thickness direction. The porosity is relatively lower than the low porosity regions of other regions, and In the above-mentioned low porosity region, a part of the constituent fibers loses the fiber form and becomes a melted and solidified state, and the remaining part of the constituent fibers maintains the fiber form.

＜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＞ The stretchable sheet as in the above <2>, wherein 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 fusion portion located on both sides of the elastic member The part between the fusion part becomes a substantially flat part compared with 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 low porosity region 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 of the second sheet facing the elastic member is in close contact with the elastic member. ＜7＞ The stretchable sheet according to any one of the above <1> to <6>, wherein the low porosity region is in close contact with the surface of the elastic member opposite to the low porosity region, and becomes a surface that follows the surface Shape of shape. ＜8＞ The stretchable sheet according to any one of the above <1> to <7>, wherein when the stretchable sheet is viewed in a cross-section in the orthogonal direction, when the low porosity region is viewed in the orthogonal direction , The difference between the maximum thickness and the minimum thickness in the low porosity region is 5 μm or less. ＜9＞ The stretchable sheet according to any one of the above <1> to <8>, wherein the low porosity region and the elastic member are not fused with each other. ＜10＞ The stretchable sheet of any one of the above <1> to <9>, wherein the first sheet is a hydrophilic sheet.

＜11＞ The stretchable sheet according to any one of the above <1> to <10>, wherein the second sheet is a hydrophobic sheet. ＜12＞ The stretchable sheet according to any one of the above <1> to <11>, wherein the fusion part located on both sides of the elastic member is fused with the side edge of the elastic member side in one fusion part and 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. ＜13＞ The stretchable sheet of any one of the above <1> to <12>, wherein the interval Le between adjacent elastic members is 1 mm or more and 10 mm or less, preferably 1 mm or more and 8 mm or less, more preferably Above 1 mm and below 6 mm. ＜14＞ The stretchable sheet according to any one of the above <1> to <13>, wherein the interval Lf between the fusion portions adjacent in the extending direction of the elastic member is 6 mm or less, preferably 5 mm or less, and more Preferably, it is 3 mm or less. ＜15＞ The stretchable sheet of any one of the above <1> to <14>, wherein the length of the fusion portion along the extension direction of the elastic member is 3 mm or less, preferably 2 mm or less, more preferably 1 mm or less. ＜16＞ The stretchable sheet of any one of the above <1> to <15>, 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. ＜17＞ The stretchable sheet according to any one of the above <1> to <16>, wherein between the adjacent elastic members and the adjacent fused parts in the orthogonal direction, there is arranged The other fusion part where the first sheet and the second sheet are joined. ＜18＞ For the stretchable sheet of the above-mentioned <17>, when the interval between the adjacent elastic members is set to Le, and the length of the other fusion portion along the orthogonal direction is set to L16, the value of L16/Le It is 0.25 or more, preferably 0.50 or more, more preferably 0.70 or more. ＜19＞ The stretchable sheet of <17> or <18>, wherein the length of the other fusion portion along the extension direction of the elastic member is 3 mm or less, preferably 2 mm or less, and more preferably 1 mm or less. ＜20＞ The stretchable sheet according to any one of the above <1> to <19>, wherein the first sheet has a plurality of regions with different void ratios between the fusion portions.

<21> The stretchable sheet as in the above <20>, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and the above-mentioned region with a relatively low porosity Forms the part that is in contact with the skin. <22> The stretchable sheet as in the above <20> or <21>, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and the porosity is relatively The lower area is located in the center of the above-mentioned orthogonal direction between the above-mentioned fusion parts. <23> The stretchable sheet of any one of the above <20> to <22>, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and The length in the orthogonal direction of the region with relatively low porosity is the same as or longer than the length in the orthogonal direction of the region with relatively high porosity. <24> The stretchable sheet of any one of the above <20> to <23>, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and The length of the orthogonal direction of the region with relatively low porosity relative to the length of the orthogonal direction of the region with relatively high porosity is 100% or more, preferably 120% or more, and 200 % Or less, preferably 150% or less. <25> The stretchable sheet of any one of the above <20> to <24>, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and The difference in the porosity between the region with a relatively high porosity and the region with a relatively low porosity is 30% or more. <26> The stretchable sheet according to any one of the above <1> to <25>, wherein the first sheet is formed with a protrusion protruding away from the elastic member along the thickness direction of the stretchable sheet unit. <27> The stretchable sheet according to any one of the above <1> to <26>, in which the first sheet and the second sheet are respectively formed with convex portions protruding so as to be separated from each other in the thickness direction. <28> The stretchable sheet of the above <26> or <27>, wherein the convex portion is the part that follows the shape of the elastic member at the position where the first sheet and the second sheet overlap the elastic member Different parts extend continuously along the above-mentioned orthogonal direction, and a plurality of folds are formed by the convex part. <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 in the stretchable sheet, the first sheet and the second sheet are two separate sheets. ＜32＞ The stretchable sheet according to any one of the above <1> to <30>, 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. ＜33＞ 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 <32>. ＜34＞ The absorbent article of the above-mentioned <33>, wherein the second sheet of the above-mentioned stretchable sheet is arranged so as to face the wearer's skin. ＜35＞ The absorbent article of the above-mentioned <33>, wherein the second sheet of the above-mentioned stretchable sheet is arranged so as to face the clothing side. [Industrial availability]

As described in detail above, according to the present invention, there is provided a stretchable sheet and absorbent article excellent in the effect of removing sweat from the skin.

10: Stretchable sheet 11: The first sheet 11a: Original film 12: The second sheet 12a: Original film 13: Elastic member 13a: winding body 15: The first fusion part 15a: The first fusion part 15b: The first fusion part 16: The second fusion part 16a: The second fusion part 16b: The second fusion part 17: Convex 20: Low porosity area 21: area 30: Ultrasonic fusion part 31: Welding head 32: Undertake roll 40: Buttress 41: Buttress 42: recess 100: device 151a: Side edge 151b: side edge a: diameter b: depth c: width D: Interval of the first fusion part d2: diameter E: Khan L16: length Le: interval Lf: interval R: Rotation direction S: skin X: direction Y: direction Z: 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. Figs. 4(a) to (c) are diagrams for explaining the effect of the stretchable sheet shown in Fig. 1. Fig. 5 is a diagram explaining the effect of the stretchable sheet shown in Fig. 1 (corresponding to the diagram of Fig. 4). Fig. 6 is a perspective view showing a relaxed state of the stretchable sheet shown in Fig. 1. Fig. 7 is a microscope image of an example of the low-porosity region of the present invention. Fig. 8 is a schematic diagram showing an apparatus that can be preferably used for manufacturing the stretchable sheet of the present invention. Fig. 9 is an enlarged view of the main part of the device shown in Fig. 8. Fig. 10 is an enlarged view of the first contact portion shown in Fig. 9.

10: Stretchable sheet

11: The first sheet

12: The second sheet

13: Elastic member

15: The first fusion part

15a: The first fusion part

15b: The first fusion part

16: The second fusion part

16a: The second fusion part

16b: The second fusion part

L16: length

Le: interval

Lf: interval

X: direction

Y: direction

Claims (35)

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 formation position of the fusion portion, the second sheet has the inter-fiber composition in the entire area between the fusion portions in the thickness direction. The porosity is relatively lower than the low porosity regions of other regions, and In the above-mentioned low porosity region, a part of the constituent fibers loses the fiber form and becomes a melted and solidified state, and the remaining part of the constituent fibers maintains the fiber form. The stretchable sheet according to claim 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 side of the elastic member Compared with the portion on the second sheet side of the elastic member, the portion swells toward the outside in the thickness direction of the stretchable sheet, 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. The stretchable sheet of claim 2, wherein the second sheet side of the elastic member is the fusion portion located on both sides of the elastic member when viewed in a cross-section in a direction orthogonal to the extending direction of the elastic member The part between the fusion part becomes a substantially flat part compared with the part other than the fusion part. The stretchable sheet according to claim 2, wherein between the fusion portions, the surface on the second sheet side is substantially flat, and on the other hand, the surface on the first sheet side bulges toward the outer side in the thickness direction. The stretchable sheet according to claim 1, wherein the low porosity area has a shape following the shape of the elastic member. The stretchable sheet according to claim 1, 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 position where the fusion portion is formed, the second sheet and the elastic member The opposite surface is in close contact with the elastic member. The stretchable sheet according to claim 1, wherein the low-porosity region is in close contact with the surface of the elastic member opposite to the low-porosity region, and has a shape that follows the shape of the surface. The stretchable sheet of claim 1, wherein when the stretchable sheet is viewed in a cross section along the orthogonal direction, when the low porosity area is viewed along the orthogonal direction, the largest of the low porosity area The difference between the thickness and the minimum thickness is 5 μm or less. The stretchable sheet according to claim 1, wherein the low porosity region and the elastic member are not fused with each other. The stretchable sheet according to claim 1, wherein the first sheet is a hydrophilic sheet. The stretchable sheet according to claim 1, wherein the second sheet is a hydrophobic sheet. The stretchable sheet according to claim 1, wherein with regard to the fusion portion located on both sides of the elastic member, the side edge of the elastic member side in one fusion portion and the side edge of the elastic member side in the other fusion portion When the interval between the edges is set to D, and 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. The stretchable sheet of claim 1, wherein the interval Le between adjacent elastic members is 1 mm or more and 10 mm or less. The stretchable sheet according to claim 1, wherein the interval Lf between the fusion portions adjacent in the extending direction of the elastic member is 6 mm or less. The stretchable sheet according to claim 1, wherein the length of the fusion portion along the extending direction of the elastic member is 3 mm or less. The stretchable sheet according to claim 1, 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. 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 of the joint. For example, the stretchable sheet of claim 17, in which the interval between adjacent elastic members is set to Le, and the length of the other fusion portion along the orthogonal direction is set to L16, the value of L16/Le is Above 0.25. The stretchable sheet according to claim 17, wherein the length of the other fusion portion along the extending direction of the elastic member is 3 mm or less. The stretchable sheet according to claim 1, wherein the first sheet has a plurality of regions with different void ratios between the fusion portions. The stretchable sheet of claim 20, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and The area with relatively low porosity forms the part in contact with the skin. The stretchable sheet of claim 20, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and The region with the relatively low porosity is located at the center of the orthogonal direction between the fusion portions. The stretchable sheet of claim 20, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and The length in the orthogonal direction of the region with relatively low porosity is the same as or longer than the length in the orthogonal direction of the region with relatively high porosity. The stretchable sheet of claim 20, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and The length in the orthogonal direction of the region with relatively low porosity relative to the length of the orthogonal direction in the region with relatively high porosity is 100% or more and 200% or less. The stretchable sheet of claim 20, wherein the first sheet has a region with a relatively high porosity and a region with a relatively low porosity among the plurality of regions, and The region with relatively high porosity and the region with relatively low porosity have a void ratio difference of 30% or more. The stretchable sheet according to claim 1, wherein the first sheet is formed with a convex portion protruding in a direction away from the elastic member along the thickness direction of the stretchable sheet. The stretchable sheet according to claim 1, wherein the first sheet and the second sheet are respectively formed with convex portions protruding so as to be separated from each other in the thickness direction. Such as the stretchable sheet of claim 26 or 27, wherein the convex portion is a part different from the portion of the first sheet and the second sheet that follows the shape of the elastic member at a position overlapping with the elastic member, and along It extends continuously in the above-mentioned orthogonal direction, and a plurality of folds are formed by the convex portion. Such as the stretchable sheet of claim 1, wherein 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 and 50 g/m ² or less. The stretchable sheet of claim 29, wherein the flexural strength of the non-woven fabric is 50 cN or less in the direction orthogonal to the machine travel direction, and 70 cN or less in the machine travel direction. The stretchable sheet according to claim 1, wherein among the stretchable sheets described above, the first sheet and the second sheet are two separate sheets. The stretchable sheet of claim 1, wherein among the stretchable sheets described above, the first sheet and the second sheet are formed by bending one sheet to form two opposing sides, and the part constituting one side is The part of the first sheet that constitutes the other side is the second sheet. 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. The absorbent article according to claim 33, wherein the second sheet of the above-mentioned stretchable sheet is arranged so as to face the skin of the wearer. The absorbent article according to claim 33, wherein the second sheet of the above-mentioned stretchable sheet is arranged so as to face the clothing side.

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