Stretchable sheet and stretchable sheet production method

Abstract

A stretchable sheet (5) comprises an elastic sheet (6) and an air-permeable sheet (7, 8) which is fused to the elastic sheet (6), in a state in which the elastic sheet (6) is stretched in a prescribed direction (D1), by a plurality of fused parts (M) that are intermittently formed in the prescribed direction (D1) and in an orthogonal direction (D2) orthogonal to the prescribed direction (D1). The fused parts (M) include a plurality of long fused parts (M1) which each have a planar shape having a lengthwise dimension (L1) in the orthogonal direction (D2) that is longer than the width dimension (W1) thereof in the prescribed direction, and which are disposed such that the gap (G1) in the orthogonal direction (D2) between two adjacent long fused parts (M1) in the orthogonal direction (D2) is greater than whichever of the respective lengthwise dimensions (L1) of the two long fused parts (M1) is longer. The elastic sheet (6) has a plurality of penetration parts (6c) which are formed on both sides of the long fused parts (M1) in the prescribed direction (D1) and which pass through between the front and back of the elastic sheet (6).

Description

Stretchable sheet and method for manufacturing the same

[0001] The present invention relates to a stretchable sheet having an elastic sheet having elasticity and an air-permeable sheet having air permeability and intermittently welded to the elastic sheet in a predetermined direction while the elastic sheet is stretched in the predetermined direction, and to a method for manufacturing the stretchable sheet.

[0002] One example of a conventional stretchable sheet is the stretchable composite sheet described in Patent Document 1. This stretchable composite sheet includes a first nonwoven fabric, a second nonwoven fabric, and an elastic member sandwiched between the first nonwoven fabric and the second nonwoven fabric and welded to the first nonwoven fabric and the second nonwoven fabric.

[0003] The elastic member is fixed to the first and second nonwoven fabrics by welded joints formed intermittently in the predetermined direction while stretched in the predetermined direction. Therefore, when the elastic member is released from tension, the elastic member contracts, causing the multiple welded joints to move toward each other, resulting in the first and second nonwoven fabrics sagging so that an uneven shape appears on their surfaces. Conversely, when tension is applied in the predetermined direction to the elastic member in this contracted state, the first and second nonwoven fabrics unfold as described above, and the elastic member stretches.

[0004] Furthermore, Patent Document 1 describes the use of an olefin-based elastomer having thermoplastic properties and a styrene-based elastomer having thermoplastic properties as materials for the elastic member.

[0005] Furthermore, Patent Document 1 also discloses a manufacturing apparatus for manufacturing the stretchable sheet from the material of the elastic member in a continuous process. Specifically, this manufacturing apparatus is configured to heat and melt the material of the elastic member to form a film-like intermediate, cool this intermediate to a temperature range where it can be elastically deformed to form the elastic member, and then weld the elastic member to both nonwoven fabrics in a stretched state.

[0006] Patent document 2 also discloses that by forming a joint for joining the elastic film sandwiched between the first sheet layer and the second sheet layer while the elastic film is stretched, through holes are formed on both sides of the stretching direction of the elastic film relative to the joint, thereby improving breathability.

[0007] However, when a stretchable sheet is produced in a continuous process from elastic material, as in the manufacturing apparatus described in Patent Document 1, there are restrictions on the material of the elastic material. Specifically, when an olefin-based elastomer is used, the required elasticity cannot be obtained simply by cooling the film-like intermediate product; the intermediate product must be left to stand for a predetermined period of time after cooling.

[0008] On the other hand, when a styrene-based elastomer is used, a stretchable sheet can be produced in a single process from the material of the elastic member. However, when the stretchable sheet is used in a baby diaper, if the elastic member is kept stretched for a long period of time under relatively high temperature conditions (e.g., 40°C), the elastic member may break in a direction perpendicular to the stretching direction, so that the joints join together.

[0009] Therefore, it is necessary to prevent the above-mentioned breakage, but it is also necessary to form through holes adjacent to the joints to ensure breathability, as described in Patent Document 2.

[0010] International Publication No. 2019 / 150801 Patent No. 6709550

[0011] An object of the present invention is to provide a stretchable sheet made of a styrene-based elastomer that can prevent breakage while ensuring breathability of the elastic sheet, and a method for producing the same.

[0012] In order to solve the above-mentioned problems, the present invention provides a stretchable sheet comprising: an elastic sheet made of a thermoplastic resin whose main component is a styrene-based elastomer; and a breathable sheet which is welded to the elastic sheet with a plurality of welds intermittently formed in a predetermined direction and an orthogonal direction perpendicular to the predetermined direction when the elastic sheet is stretched in the predetermined direction, wherein the plurality of welds are long welds having a planar shape whose longitudinal dimension in the orthogonal direction is longer than its width dimension in the predetermined direction, and which are arranged so that the orthogonal distance between two adjacent long welds is wider than the longer of the longitudinal dimensions of the two long welds; and the elastic sheet has a plurality of through-holes which are formed on both sides of the plurality of long welds in the predetermined direction and which penetrate the elastic sheet from front to back.

[0013] The present invention also provides a manufacturing method for manufacturing the stretchable sheet, which includes melting a thermoplastic resin containing a styrene-based elastomer as a main component, forming a sheet-like intermediate using the melted thermoplastic resin, cooling the intermediate to a temperature range where the intermediate obtains a predetermined elasticity, thereby forming the elastic sheet, applying a predetermined tension to the elastic sheet in the predetermined direction, and forming a plurality of welded portions intermittently in the predetermined direction and the perpendicular direction on the elastic sheet stretched by the tension. and welding the breathable sheet to a sheet, wherein the plurality of welds are a plurality of long welds having a planar shape whose longitudinal dimension in the orthogonal direction is longer than the width dimension in the specified direction, and the plurality of long welds are arranged so that the orthogonal distance between two adjacent long welds in the orthogonal direction is wider than the longer of the longitudinal dimensions of the two long welds, and when forming the plurality of welds on the elastic sheet, a plurality of through holes that penetrate the elastic sheet from front to back are formed on both sides of the specified direction of the plurality of long welds.

[0014] According to the present invention, it is possible to prevent breakage of an elastic sheet made of a styrene-based elastomer while ensuring the breathability of the elastic sheet.

[0015] 9 is a front view schematically showing a manufacturing apparatus for manufacturing a stretch sheet according to the present invention. FIG. 10 is a plan view showing a stretch sheet according to a first embodiment of the present invention, with both ends in a predetermined direction and the center in the orthogonal direction omitted. FIG. 11 is an enlarged view of section III in FIG. 2. FIG. 12 is a cross-sectional view taken along line IV-IV in FIG. 2. FIG. 13 shows the stretch sheet shown in FIG. 4 in a state released from tension. FIG. 14 is an enlarged plan view of one long welded portion in the stretch sheet shown in FIG. 4. FIG. 15 is a plan view corresponding to FIG. 6, showing another long welded portion. FIG. 16 is a plan view corresponding to FIG. 6, showing a comparative example of a welded portion. FIG. 16 is a plan view showing a stretch sheet according to a second embodiment of the present invention, with both ends in a predetermined direction and the center in the orthogonal direction omitted. FIG. 17 is an enlarged view of section X in FIG. FIG. 18 is a plan view showing an example of a worn article using a stretch sheet according to the present invention.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are examples that embody the present invention and are not intended to limit the technical scope of the present invention.

[0017] 1 is a front view showing a schematic diagram of a manufacturing apparatus 1 for manufacturing a stretchable sheet 5 according to the present invention. The manufacturing apparatus 1 is configured to mold a sheet-like elastic sheet 6 from a thermoplastic resin containing a styrene-based elastomer as a main component, and to produce the stretchable sheet 5 by sandwiching the elastic sheet 6 in a stretched state between a first breathable sheet 7 and a second breathable sheet 8 and welding the elastic sheet 6 to both breathable sheets 7, 8.

[0018] Referring to Figure 1, the manufacturing apparatus 1 includes a sheet forming mechanism 2 for forming an elastic sheet 6, and a stretch welding mechanism 3 for sandwiching the elastic sheet 6 between a first breathable sheet 7 and a second breathable sheet 8 in a stretched state and welding the elastic sheet 6 to both breathable sheets 7 and 8.

[0019] The sheet forming mechanism 2 has a molding section 2a that melts a thermoplastic resin and molds the molten thermoplastic resin into a sheet-shaped intermediate 6a, a cooling section 2b that cools the intermediate 6a molded by the molding section 2a to form an elastic sheet 6, and a relay roll 2c that relays the elastic sheet 6 from the cooling section 2b to the stretch welding mechanism 3.

[0020] The molding section 2a has a heater (not shown) that melts the thermoplastic resin, a storage section 2a1 that stores the thermoplastic resin melted by the heater, and a discharge section 2a2 that forms the thermoplastic resin stored in the storage section 2a1 into a sheet and discharges it.

[0021] The cooling unit 2b cools the intermediate 6a discharged from the discharge unit 2a2 to a temperature at which a predetermined elasticity is obtained, and conveys the elastic sheet 6 formed by this cooling to the relay roll 2c. Specifically, the cooling unit 2b includes a transport roll 2b1 having an outer circumferential surface for holding the intermediate 6a, and a cooling mechanism (not shown) for cooling the outer circumferential surface of the transport roll 2b1. The transport roll 2b1 is driven to rotate counterclockwise in FIG. 1 around a predetermined axis (an axis extending perpendicular to the plane of FIG. 1) by a motor (not shown). The transport roll 2b1 is provided below the discharge unit 2a2, and the intermediate 6a discharged from the discharge unit 2a2 is placed on the outer circumferential surface of the transport roll 2b1. Therefore, the intermediate 6a is cooled in a range E1 within the rotation range of the transport roll 2b1 where the intermediate 6a is placed on the outer circumferential surface, and the elastic sheet 6 is formed. Furthermore, the rotation speed of the transport roll 2b1 is higher than the speed at which the intermediate material 6a is discharged from the discharge portion 2a2 and reaches the transport roll 2b1. Therefore, the intermediate material 6a is stretched in a range E2 from the discharge portion 2a2 to the transport roll 2b1. The cooling mechanism has a refrigerant passage (not shown) provided in the transport roll 2b1 and a refrigerant (not shown) flowing through the refrigerant passage.

[0022] The relay roll 2c conveys the elastic sheet 6 formed by the cooling unit 2b to the stretch welding mechanism 3 while changing the conveying direction of the elastic sheet 6. Specifically, the relay roll 2c is configured to be rotatable about an axis parallel to the rotation axis of the conveying roll 2b1. Note that if the cooling unit 2b does not have enough cooling capacity for the intermediate product 6a, the relay roll 2c may have the function of cooling the intermediate product 6a (the relay roll 2c may constitute part of the cooling unit 2b). On the other hand, if the cooling unit 2b has sufficient cooling capacity and the elastic sheet 6 can be conveyed directly from the cooling unit 2b to the stretch welding mechanism 3, the relay roll 2c may be omitted.

[0023] The stretch welding mechanism 3 includes a pair of nip rolls 3a, 3b that sandwich the elastic sheet 6 and transport the elastic sheet 6, an anvil roll 3c having an outer surface that can adsorb the elastic sheet 6, a first supply roll 3d that supplies a first breathable sheet 7 between the outer surface of the anvil roll 3c and the elastic sheet 6, a pair of guide rolls 3e, 3f that supply a second breathable sheet 8 to the outside of the elastic sheet 6 on the outer surface of the anvil roll 3c, and an ultrasonic welding unit 3g that ultrasonically welds the first breathable sheet 7 and the second breathable sheet 8 to the elastic sheet 6 between the outer surface of the anvil roll 3c.

[0024] Nip rolls 3a and 3b transport elastic sheet 6 at the same speed as the transport speed of intermediate material 6a or elastic sheet 6 by transport roll 2b1 and relay roll 2c. Specifically, nip rolls 3a and 3b are driven to rotate about an axis parallel to the rotation axis of transport roll 2b1 by a motor (not shown). Nip roll 3a is driven to rotate clockwise in Fig. 1, and nip roll 3b is driven to rotate counterclockwise in Fig. 1.

[0025] The anvil roll 3c conveys the elastic sheet 6 and both breathable sheets 7 and 8 at a speed higher than the speed at which the nip rolls 3a and 3b convey the elastic sheet 6. As a result, the elastic sheet 6 is subjected to a predetermined tension between the nip rolls 3a and 3b and the anvil roll 3c, and is stretched in the conveyance direction. Specifically, the anvil roll 3c is driven by a motor (not shown) to rotate counterclockwise in FIG. 1 around an axis parallel to the rotation axis of the conveyance roll 2b1.

[0026] The anvil roll 3c also has a suction mechanism (not shown) for adsorbing the elastic sheet 6 and both breathable sheets 7 and 8 to the outer circumferential surface of the anvil roll 3c in order to suppress shrinkage of the elastic sheet 6 in the width direction (axial direction of the anvil roll 3c). The suction mechanism has a suction chamber (not shown) formed in the anvil roll 3c and connected to a suction source (not shown), and a plurality of suction holes (not shown) opening in the outer circumferential surface of the anvil roll 3c for connecting the suction chamber to the outside in the radial direction of the anvil roll 3c.

[0027] The outer peripheral surface of the anvil roll 3c has an adsorption area 3c1 provided with the above-mentioned plurality of suction holes and a later-described welding area 3c2 provided with a welding pattern for forming a plurality of welds M (see FIG. 2) between the adsorption area 3c1 and the later-described ultrasonic welds 3g. The adsorption area 3c1 and the welding area 3c2 are provided in different positions (for example, different positions in a direction perpendicular to the plane of the paper in FIG. 1). If adsorption of the elastic sheet 6 and the breathable sheets 7 and 8 to the outer peripheral surface of the anvil roll 3 is not necessary, the adsorption mechanism can be omitted.

[0028] The first supply roll 3d is disposed relative to the anvil roll 3c so that the first breathable sheet 7 is supplied to a position upstream in the circumferential direction of the anvil roll 3c of the introduction position P1 at which the elastic sheet 6 is introduced. The first supply roll 3d is configured to be rotatable about an axis parallel to the rotation axis of the transport roll 2b1.

[0029] The guide roll 3e is disposed relative to the anvil roll 3c so that the second breathable sheet 8 is supplied to a position downstream in the rotation direction of the anvil roll 3c of the introduction position P1 of the elastic sheet 6 in the circumferential direction of the anvil roll 3c. The guide roll 3f is for guiding the second breathable sheet 8 to the guide roll 3e. Both guide rolls 3e, 3f are configured to be rotatable about an axis parallel to the rotation axis of the transport roll 2b1. Note that the guide roll 3f may be omitted depending on the transport path of the second breathable sheet 8.

[0030] The ultrasonic welding section 3g applies ultrasonic energy to the elastic sheet 6, the first breathable sheet 7, and the second breathable sheet 8 held on the outer peripheral surface of the anvil roll 3c, thereby melting at least the elastic sheet 6 among these sheets 6, 7, and 8, and welding both breathable sheets 7 and 8 to the elastic sheet 6 (forming a plurality of welded sections M shown in FIG. 2). By welding the elastic sheet 6 at the welded sections M, a plurality of penetration sections 6c (see FIG. 4) are formed on both sides of the plurality of welded sections M1 in the predetermined direction D1, penetrating the elastic sheet 6 from front to back.

[0031] Specifically, as shown in FIG. 1, the ultrasonic welding portion 3g has an ultrasonic horn 3g1 arranged to face the outer peripheral surface of the anvil roll 3c, and an ultrasonic generator 3g2 that transmits ultrasonic vibrations to the ultrasonic horn 3g1.

[0032] The ultrasonic horn 3g1 has an opposing surface 3g11 that faces the welding region 3c2 provided on the outer circumferential surface of the anvil roll 3c. Meanwhile, the welding region 3c2 of the anvil roll 3c is configured to form a plurality of welding portions M (see FIG. 2) on the elastic sheet 6 that are intermittently arranged in a predetermined direction D1 (the conveying direction of the elastic sheet 6; see FIG. 2) and an orthogonal direction D2 (a direction orthogonal to the plane of the paper in FIG. 1; see FIG. 2) in response to the relative rotation of the welding region 3c2 with respect to the opposing surface 3g11. Specifically, the welding region 3c2 has a base surface 3c21 that is relatively distant from the opposing surface 3g11 and a plurality of protrusions 3c22 that protrude from the base surface radially outward of the anvil roll 3c and form a welding pattern. The protrusions 3c22 are spaced apart from one another on the base surface 3c21 in the circumferential and axial directions of the anvil roll 3c. The plurality of protrusions 3c22 include elongated protrusions 3c22 extending in the axial direction of the anvil roll 3c. As the anvil roll 3c rotates, the protrusions 3c22 sequentially face the opposing surface 3g11, thereby forming welded portions M (see FIG. 2).

[0033] In this embodiment, the manufacturing apparatus 1 having the ultrasonic welding unit 3g has been described, but instead of the ultrasonic welding unit 3g, a heater, infrared rays, etc. may be used to form the welding unit M. In other words, instead of welding by applying ultrasonic vibrations, welding using a heat source, infrared rays, etc. may also be employed.

[0034] Furthermore, the number, positions, and ranges of the molding section 2a, cooling section 2b, relay roll 2c, transport roll 2b1, etc., can be appropriately changed as needed in the sheet forming mechanism 2. Furthermore, although an example of forming the elastic sheet 6 from a thermoplastic resin has been described, the stretchable sheet 5 may also be produced by joining an already formed elastic sheet 6 to the breathable sheets 7 and 8 in a stretched state.

[0035] The structure of the stretchable sheet 5 manufactured by the above-described manufacturing apparatus 1 will be described below with reference to Figs. 2 to 4. Fig. 2 is a plan view showing both ends in a predetermined direction and the center in the orthogonal direction of the stretchable sheet according to the first embodiment of the present invention, with the latter omitted. Fig. 3 is an enlarged view of part III in Fig. 2. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2.

[0036] The stretchable sheet 5 includes an elastic sheet 6, and a first breathable sheet 7 and a second breathable sheet 8 welded to the elastic sheet 6 at a plurality of welded portions M while the elastic sheet 6 is stretched in a predetermined direction D1. In this embodiment, two breathable sheets 7 and 8 are used, but one of these sheets may be omitted.

[0037] The elastic sheet 6 is made of a thermoplastic resin containing a styrene-based elastomer as a main component. For example, "Quintac (registered trademark)" manufactured by Zeon Corporation can be used as the elastic sheet 6.

[0038] The first breathable sheet 7 and the second breathable sheet 8 each have breathability. As the first breathable sheet 7 and the second breathable sheet 8, for example, a nonwoven fabric can be used.

[0039] The multiple welded portions M have solidified portions formed by melting and then solidifying a portion of the elastic sheet 6, and fixed portions of the first breathable sheet 7 and the second breathable sheet 8 fixed to the solidified portions.

[0040] Specifically, the multiple welds M include multiple long welds M1 having a planar shape in which the longitudinal dimension L1 in the orthogonal direction D2 is longer than the width dimension W1 in the predetermined direction D1, and multiple circular welds M2 having a circular planar shape with a diameter W2. The diameter W2 of the circular welds M2 is smaller than the longitudinal dimension L1 of the long welds M1. Note that although circular welds M2 are shown as an example of welds other than the long welds M1, welds having a planar shape in which the dimension in the orthogonal direction D2 is equal to or smaller than the dimension in the predetermined direction can also be used as welds other than the long welds M1.

[0041] The plurality of welded portions M are arranged side by side along a plurality of reference lines MR that extend in the orthogonal direction D2 and are arranged intermittently in the predetermined direction D1.

[0042] A plurality of welds M are arranged in a row along each reference line MR, with one long weld M1 and at least one (two in the example of FIG. 3 ) circular weld M2 alternating. A distance G2 between adjacent long welds M1 and circular welds M2 in the orthogonal direction D2 along each reference line MR is longer than the longitudinal dimension L1 of the long weld M1. From the perspective of breathability alone, the distance G2 may be equal to or shorter than the longitudinal dimension L1; however, from the perspective of preventing breakage of the elastic sheet 6, the distance G2 is preferably longer than the longitudinal dimension L1.

[0043] Furthermore, the multiple welds M are arranged on two adjacent reference lines MR so that the long welds M1 and the two circular welds M2 are aligned in the predetermined direction D1. Specifically, one edge in the orthogonal direction D2 of the circular welds M2 on one reference line MR that is located on one side of the orthogonal direction D2 is aligned with one edge in the orthogonal direction D2 of the long welds M1 on the other reference line MR. Furthermore, the other edge in the orthogonal direction D2 of the circular welds M2 on one reference line MR that is located on the other side of the orthogonal direction D2 is aligned with the other edge in the orthogonal direction D2 of the long welds M1 on the other reference line MR. That is, the longitudinal dimension L1 of the long welded portion M1 is the same as the distance O1 between the edges of the two circular welded portions M2 that are adjacent to each other in the orthogonal direction D2. Note that the longitudinal dimension L1 of the long welded portion M1 may be set to a dimension different from the distance O1.

[0044] Furthermore, at two reference lines MR adjacent to each other in the predetermined direction D1, the long welds M1 and the circular welds M2 (an example of another weld) are arranged so that the distance MI1 between the long welds M1 and the circular welds M2 (an example of another weld) that are closest to each other in the predetermined direction D1 is greater than the longitudinal dimension L1 of the long welds M1. Note that the distance MI1 may be equal to or smaller than the longitudinal dimension L1.

[0045] All of the long welds M1 have the same longitudinal dimension L1 and the same width dimension W1. Note that at least one of the multiple long welds M1 may have a longitudinal dimension or width dimension different from the other long welds M1.

[0046] All long welded portions M1 have rounded portions at both ends in the orthogonal direction D2. The radius R1 of the rounded portion is half the width W1 of the long welded portion M1. Note that at least one long welded portion M1 does not necessarily have a rounded portion. Furthermore, the radius R1 of the rounded portion may be set to a dimension other than half the width W1 of the long welded portion M1.

[0047] All of the circular welds M2 have the same diameter W2. However, at least one of the multiple circular welds M2 may have a diameter different from the other circular welds M2.

[0048] Furthermore, the width W1 of the long welded portion M1 is the same as the diameter W2 of the circular welded portion W2, although the width W1 of the long welded portion M1 may be set to a dimension different from the diameter W2 of the circular welded portion M2.

[0049] On each reference line MR, two long welds M1 are arranged so that the distance G1 in the orthogonal direction D2 between two adjacent long welds M1 in the orthogonal direction D2 is wider than the longest of the longitudinal dimensions L1 of the two long welds M1. Furthermore, multiple welds M are arranged so that the distance G1 is wider than the longest of the longitudinal dimensions L1 of all the long welds M1. In this embodiment, all long welds M1 have the same longitudinal dimension L1, so all distances G1 are wider than the long dimension L1. Furthermore, the same distance G1 is set for all reference lines MR. It is also possible to set multiple different distances G1 on a specific reference line MR. Alternatively or in addition, a different distance G1 can be set for each reference line MR.

[0050] 2, the multiple long welds M1 include an edge-side long weld M11 adjacent to the edge 6b of the elastic sheet 6 in the orthogonal direction D2. The edge-side long weld M11 is arranged so that the distance G4 from the edge-side long weld M11 to the edge 6b of the elastic sheet 6 is greater than the longitudinal dimension of the edge-side long weld M11 (the longer of the longitudinal dimensions of the two long welds M1). Note that the distance G4 may be equal to or shorter than the longitudinal dimension L1 of the edge-side long weld M11.

[0051] Furthermore, as shown in Figure 4, the elastic sheet 6 has a plurality of through-holes 6c formed on both sides of the plurality of long welds M1 in the predetermined direction D1 and penetrating the elastic sheet 6 from front to back. The solidified portions of the elastic sheet 6 at the long welds M1 lose their elasticity due to thermal welding. Therefore, as shown in Figures 4 and 6, when tension is applied to the stretchable sheet 5 in the predetermined direction D1, the shape of the solidified portions of the long welds M1 is maintained while the portions of the elastic sheet 6 adjacent to the solidified portions in the predetermined direction D1 (hereinafter referred to as "adjacent portions") move away from the solidified portions, thereby expanding the opening area of ​​the through-holes 6c in the predetermined direction D1. Here, the solidified portions of the elastic sheet 6 at the long welds M1 have a longitudinal dimension L1 in the orthogonal direction D2 that is greater than their width dimension W1 in the predetermined direction D1. 8, for example, compared to a circular welded portion M12 having a radius WE equal to the longitudinal dimension L1 of the long welded portion M1, the distance by which adjacent portions of the solidified portion of the elastic sheet 6 are separated from the solidified portion when tension is applied in the predetermined direction D1 can be made larger. As a result, a large opening area can be ensured at the through-hole 6c. Although not shown, the circular welded portion M2 also has a solidified portion of the elastic sheet 6, and through-holes that penetrate the elastic sheet 6 from front to back are formed on both sides of the solidified portion of the elastic sheet 6 in the predetermined direction D1.

[0052] Although the long weld M1 having rounded ends in the orthogonal direction D2 is shown as an example in order to obtain a large opening area in the through-hole 6c, the shape of the long weld M1 is not limited to this. For example, as shown in Fig. 7, an elliptical long weld M11 having a major axis aligned along the orthogonal direction D2 may be formed.

[0053] Furthermore, when the stretchable sheet 5 is released from the tension in the predetermined direction D1, the elastic sheet 6 contracts in the predetermined direction D1 so that the multiple welded portions M move closer to the predetermined direction D1 while maintaining the size of the solidified portions of the welded portions M, as shown in Fig. 5. The contraction of the elastic sheet 6 in the predetermined direction D1 causes the portions of the elastic sheet 6 adjacent to the welded portions M in the predetermined direction D1 to move closer to the welded portions M, thereby reducing the opening area of ​​the through-holes 6c. Furthermore, as the multiple welded portions M move closer to each other in the predetermined direction D1 due to the contraction of the elastic sheet 6, both breathable sheets 7, 8 slacken so that uneven shapes appear in both breathable sheets 7, 8, as shown in Fig. 5.

[0054] On the other hand, when tension is applied in the predetermined direction D1 to the elastic sheet 6 in this contracted state, the breathable sheets 7 and 8 are unfolded as described above, and the elastic sheet 6 stretches. As the elastic sheet 6 stretches, the opening area of ​​the through-hole 6c increases as described above.

[0055] Here, the method for manufacturing the stretchable sheet 5 executed by the manufacturing apparatus 1 will be summarized with reference to FIG.

[0056] The manufacturing method of the stretchable sheet 5 includes a melting process for melting a thermoplastic resin, an intermediate formation process for forming a sheet-like intermediate 6a, a stretching process for stretching the intermediate 6a, an elastic sheet formation process for forming an elastic sheet 6, a tensioning process for applying tension to the elastic sheet 6, a lamination process for laminating breathable sheets 7 and 8 onto the elastic sheet 6, and a welding process for welding the breathable sheets 7 and 8 to the elastic sheet 6.

[0057] In the melting step, the thermoplastic resin containing a styrene-based elastomer as a main component is melted. The melting step is carried out by the molding unit 2a of the manufacturing apparatus 1.

[0058] In the intermediate forming step, a sheet-like intermediate 6a is formed using molten thermoplastic resin. The intermediate forming step is performed by the molding unit 2a of the manufacturing apparatus 1.

[0059] The stretching step is carried out between the forming section 2a and the cooling section 2b in the manufacturing apparatus 1.

[0060] In the elastic sheet forming step, the intermediate 6a is cooled to a temperature range where the intermediate 6a has a predetermined elasticity, thereby forming the elastic sheet 6. The elastic sheet forming step is performed by the cooling unit 2b.

[0061] In the tension applying step, a preset tension is applied to the elastic sheet 6 in a predetermined direction D1 (the conveying direction of the elastic sheet 6). The tension applying step is performed between the nip rolls 3a, 3b and the anvil roll 3c.

[0062] In the lamination step, the first breathable sheet 7 and the second breathable sheet 8 are laminated onto the elastic sheet 6 so that the elastic sheet 6 is sandwiched between the first breathable sheet 7 and the second breathable sheet 8. The lamination step is performed by an anvil roll 3c, a first supply roll 3d, and a pair of guide rolls 3e, 3f. Note that in the lamination step, lamination of the first breathable sheet 7 or the second breathable sheet 8 onto the elastic sheet 6 may be omitted.

[0063] In the welding step, a plurality of welds M are intermittently formed in the predetermined direction D1 and the orthogonal direction D2 on the elastic sheet 6 that has been stretched by the tension applied in the tension application step, thereby welding both breathable sheets 7, 8 to the elastic sheet 6. If one of the breathable sheets 7, 8 is omitted in the lamination step, the other of the breathable sheets 7, 8 is welded to the elastic sheet 6 in the welding step.

[0064] The plurality of welds M formed in the welding process include a plurality of long welds M1 each having a planar shape in which the longitudinal dimension L1 in the orthogonal direction D2 is longer than the width dimension W1 in the predetermined direction D1. The plurality of long welds M1 are arranged such that the distance in the orthogonal direction D2 between two adjacent long welds M1 among the plurality of long welds M1 is wider than the longer of the longitudinal dimensions L1 of the two long welds M1.

[0065] Furthermore, in the welding process, a plurality of penetrations (penetrations 6c for the long welded portions M1: see Figure 4) are formed on both sides of the plurality of welded portions M (especially the long welded portions M1) in the predetermined direction D1, penetrating the elastic sheet 6 from front to back.

[0066] The welding process is carried out by an anvil roll 3c and an ultrasonic welding unit 3g.

[0067] The method for manufacturing the stretchable sheet 5 is not limited to the method carried out by the manufacturing apparatus 1 .

[0068] As described above, according to the first embodiment, the through-holes 6c are formed on both sides of the long weld M1 in the predetermined direction D1, and the elasticity of the long weld M1 itself (the solidified portion of the elastic sheet 6) is lost due to melting during welding. Therefore, when tension is applied in the predetermined direction D1, the shape of the long weld M1 is maintained, and a portion of the elastic sheet 6 adjacent to the long weld M1 in the predetermined direction D1 via the through-holes 6c separates from the long weld M1. Here, in the first embodiment, because the longitudinal dimension L1 of the long weld M1 is longer than the width dimension W1, the distance that the portion of the elastic sheet 6 moves away from the long weld M1 due to tension is longer than when the width dimension W1 is equal to or greater than the longitudinal dimension L1. Therefore, a relatively large opening area of ​​the through-holes 6c can be ensured when tension is applied.

[0069] On the other hand, when the longitudinal dimension L1 of the long welded portion M1 is longer than the width dimension W1, tension applied in the predetermined direction D1 concentrates stress in a portion of the elastic sheet 6 adjacent to the end of the long welded portion M1 in the orthogonal direction D2, making the elastic sheet 6 more susceptible to fracture. Furthermore, if a similar fracture occurs in another long welded portion M1 adjacent to the long welded portion M1 in the orthogonal direction D2, the elastic sheet 6 fractures so as to connect the two adjacent long welded portions M1. In contrast, in the first embodiment, the gap G1 in the orthogonal direction D2 between two adjacent long welded portions M1 in the orthogonal direction D2 is wider than the longer of the longitudinal dimensions L1 of the two long welded portions M1. This prevents the two adjacent long welded portions M1 from fractured so as to connect, compared to when the gap G1 is equal to or narrower than the longitudinal dimension L1 of the long welded portions M1.

[0070] Therefore, according to the first embodiment, it is possible to prevent the elastic sheet 6 made of the styrene elastomer from breaking while also ensuring the breathability of the elastic sheet 6 .

[0071] In the first embodiment, the distance G1 between two adjacent long welded portions M1 in the perpendicular direction D2 is set wider than the longest of the longitudinal dimensions L1 of all the long welded portions M1 (longitudinal dimension L1, since all longitudinal dimensions L1 are the same in the first embodiment), making it easier to manage whether the dimension of the distance G1 is appropriate in the elastic sheet 5.

[0072] According to the first embodiment, the distance MI1 between the long weld M1 (first long weld) and the circular weld M2 (another weld) in the predetermined direction D1 is greater than the longitudinal dimension L1 of the long weld M1, which allows the area of ​​the elastic sheet 6 between the long weld M1 and the circular weld M2 to be relatively large (the stretchable area to be increased). This reduces the tension applied to the long weld M1, thereby easing stress concentration at both ends of the long weld M1 in the orthogonal direction and more effectively preventing breakage of the elastic sheet 6.

[0073] According to the first embodiment, the dimension (diameter W2) of the circular weld M2 (another weld) in the orthogonal direction D2 is smaller than the longitudinal dimension L1 of the long weld M1 (first long weld). Therefore, the region of the elastic sheet 6 adjacent to the long weld M1 in the predetermined direction D1 (the stretchable region) can be relatively expanded in the predetermined direction D1 compared to when the dimension of the circular weld M2 in the orthogonal direction D2 is equal to or greater than the longitudinal dimension L1 of the long weld M1. This reduces stress concentration at both ends of the long weld M1 in the orthogonal direction D2, effectively preventing breakage of the elastic sheet 6.

[0074] According to the first embodiment, the distance G4 from the end edge side long welded portion M11 to the end edge 6b of the elastic sheet 6 is longer than the longitudinal dimension L1 of the end edge side long welded portion M11 (the longer of the longitudinal dimensions L1 of the two long welded portions M1), so breakage from the end edge side long welded portion M11 to the end edge 6b can also be effectively suppressed.

[0075] Furthermore, according to the manufacturing method of the first embodiment, it is possible to manufacture a stretchable sheet 5 that can simultaneously prevent breakage of the elastic sheet 6 and ensure the breathability of the elastic sheet 6, as described above. Furthermore, the manufacturing method uses a thermoplastic resin whose main component is a styrene-based elastomer. Therefore, unlike when using a thermoplastic resin whose main component is an olefin-based elastomer, it is not necessary to leave the cooled intermediate product for a predetermined period of time, and the stretchable sheet 5 can be manufactured from the thermoplastic resin in a continuous process.

[0076] The configuration of a stretchable sheet 5A according to a second embodiment of the present invention will be described below with reference to Figures 9 and 10. Figure 9 is a plan view of a stretchable sheet 5A according to a second embodiment of the present invention, with both ends in a predetermined direction and the center in the orthogonal direction omitted. Figure 10 is an enlarged view of the X portion in Figure 9.

[0077] Unlike the stretchable sheet 5 according to the first embodiment, the stretchable sheet 5A has only a plurality of long welded portions M1A. Specifically, the long welded portions M1A have a planar shape in which the longitudinal dimension L2 in the orthogonal direction D2 is longer than the width dimension W3 in the predetermined direction D1.

[0078] The plurality of long welded portions M1A are arranged side by side along a plurality of reference lines MRA that extend in the orthogonal direction D2 and are arranged intermittently in the predetermined direction D1.

[0079] A plurality of long welded portions M1A are arranged in a line on each reference line MRA.

[0080] Furthermore, on two adjacent reference lines MRA, multiple long welds M1A are arranged so that two long welds M1A are aligned in the predetermined direction D1. Specifically, both end edges in the orthogonal direction D2 of two long welds M1A aligned in the predetermined direction D1 are arranged at the same position in the orthogonal direction D2. Note that on two adjacent reference lines MRA, both end edges in the orthogonal direction D2 of two long welds M1A may be arranged at different positions in the orthogonal direction D2. Furthermore, long welds M1A can be arranged on one reference line MRA and on a reference line MRA adjacent to the predetermined direction D1 so as to be aligned in the predetermined direction D1 with respect to a region between two long welds M1A adjacent in the orthogonal direction D2 on one reference line MRA.

[0081] Furthermore, on two reference lines MRA adjacent to each other in the predetermined direction D1, the long welds M1A are arranged so that the distance MI2 between the long welds M1A that are closest to each other in the predetermined direction D1 is wider than the longitudinal dimension L2 of the long welds M1A. Note that the distance MI2 may be equal to or smaller than the longitudinal dimension L2.

[0082] All of the long welds M1A have the same longitudinal dimension L2 and the same width dimension W3. Note that at least one of the multiple long welds M1A may have a different longitudinal dimension or width dimension from the other long welds M1A.

[0083] All of the long welds M1A have rounded portions at both ends in the orthogonal direction D2. The radius R2 of the rounded portions is half the width W3 of the long welds M1A. Note that at least one long weld M1A does not necessarily have a rounded portion. Furthermore, the radius R2 of the rounded portion may be set to a dimension other than half the width W3 of the long welds M1A.

[0084] On each reference line MRA, two long welds M1A are arranged so that the distance G5 in the orthogonal direction D2 between two adjacent long welds M1A is greater than the longest of the longitudinal dimensions L2 of the two long welds M1A. Furthermore, multiple long welds M1A are arranged so that the distance G5 is greater than the longest of the longitudinal dimensions L2 of all the long welds M1A. In this embodiment, all long welds M1A have the same longitudinal dimension L2, so all distances G5 are greater than the longest dimension L2. Furthermore, the distance G5 is set to be the same for all reference lines MRA. It is also possible to set multiple different distances G5 on a specific reference line MRA. Alternatively or additionally, different distances G5 can be set for each reference line MRA.

[0085] 9, the multiple long welds M1A include an edge-side long weld M1A1 adjacent to the edge 6b of the elastic sheet 6 in the orthogonal direction D2. The edge-side long weld M1A1 is arranged so that the distance G6 from the edge-side long weld M1A1 to the edge 6b of the elastic sheet 6 is greater than the longitudinal dimension of the edge-side long weld M1A1 (the longer of the longitudinal dimensions of the two long welds M1A). Note that the distance G6 may be equal to or shorter than the longitudinal dimension L2 of the edge-side long weld M1A1.

[0086] Furthermore, as in the first embodiment, the elastic sheet 6 has a plurality of through-holes 6c, which are not shown in the figure, formed on both sides of the plurality of long welded portions M1A in the specified direction D1 and which penetrate the front and back of the elastic sheet 6.

[0087] Next, the configuration of a worn article 10 to which the stretchable sheet 5 according to the first or second embodiment is applied will be described with reference to Fig. 11. Fig. 11 is a plan view showing an example of a worn article using the stretchable sheet according to the present invention.

[0088] The wearable article 10 comprises a main body 11 to be worn around the waist of the wearer, an absorbent body 12 provided in the main body 11 to absorb the wearer's excrement, etc., a pair of tapes 13 for maintaining the shape of the main body 11 when worn around the waist of the wearer, and a pair of stretchable sheets 5 for imparting stretchability to the main body 11.

[0089] The main body 11 has a front abdominal portion 11a for covering the wearer's abdomen, a back portion 11b for covering the wearer's buttocks, and a crotch portion 11c extending from the front abdominal portion 11a to the back portion 11b for covering the wearer's crotch portion.

[0090] One of the pair of stretchable sheets 5 is provided in the front abdominal portion 11a, and the other of the pair of stretchable sheets 5 is provided in the back portion 11b. The stretchable sheets 5 are arranged relative to the main body 11 so that the stretch direction of both stretchable sheets 5 (the direction corresponding to the predetermined direction D1 in FIG. 2 ) follows the waist circumference of the wearer. Both stretchable sheets 5 are sandwiched between the multiple sheets that make up the main body 11. The pair of stretchable sheets 5 may be provided on the inner surface of the main body 11 (the surface facing the wearer's skin) or on the outer surface of the main body 11 (the surface facing away from the wearer's skin).

[0091] The absorbent body 12 is provided on the main body 11 so as to cover the crotch region 11c from the inside (the side facing the wearer's skin). Specifically, the absorbent body 12 has a crotch region 12a that covers the crotch region 11c, a front end region 12b that extends from the crotch region 12a toward the front abdominal region 11a to cover a portion of the front abdominal region 11a, and a rear end region 12c that extends from the crotch region 12a toward the rear region 11b to cover a portion of the rear region 11b. At least a portion of the front end region 12b overlaps a portion of one of the stretchable sheets 5 (hatched portion in FIG. 11 ) from the inside. Here, a weakened portion in which the elasticity of the elastic sheet 6 is weakened is formed in the area of ​​one of the stretchable sheets 5 where the front end region 12b overlaps. The weakened portion is formed by melting the elastic sheet 6. Similarly, at least a portion of the rear end region 12c overlaps a portion of the other of the stretchable sheets 5 (hatched portion in FIG. 11 ) from the inside. A weakened portion is formed in the area overlapping the rear end portion 12c of the other stretchable sheet 5. In this way, the front end portion 12b and the rear end portion 12c of the absorber 12 ensure a wide area for receiving excrement and the like, while suppressing deformation of the absorber 12 due to the elasticity of the stretchable sheet 5.

[0092] The pair of tapes 13 are intended to hold the shape of the main body 11 in a state in which the crotch portion 11c is passed between the wearer's legs, the front abdominal portion 11a covers the wearer's abdomen, and the back portion 11b covers the wearer's buttocks. Specifically, the pair of tapes 13 extend in directions away from both ends of the back portion 11b in the width direction (the direction along the wearer's waist). Each tape 13 is configured to be releasably attached to the outer surface of the front abdominal portion 11a (the surface facing away from the wearer's skin). For example, each tape 13 has a hook portion of a mechanical fastener, and the outer surface of the front abdominal portion 11a has a loop portion of a mechanical fastener.

[0093] 11 illustrates the wearing article 10 to which the stretchable sheet 5 is applied, but the wearing article 10 may also be applied with a stretchable sheet 5A. For example, the stretchable sheet 5A may be applied to the tape 13 of the wearing article 10.

[0094] The stretchable sheets 5, 5A may be applied to a pants-type wearing article 10 other than the tape-type wearing article 10 shown in Fig. 11. For example, the stretchable sheets 5, 5A may be applied to the waist portion of a pants-type wearing article 10.

[0095] In the first and second embodiments, the reference lines MR and MRA are parallel to the orthogonal direction D2, but at least one of the reference lines MR and MRA may be inclined with respect to the orthogonal direction.

[0096] The above-described specific embodiments mainly include inventions having the following configurations.

[0097] In order to solve the above-mentioned problems, the present invention provides a stretchable sheet comprising: an elastic sheet made of a thermoplastic resin whose main component is a styrene-based elastomer; and a breathable sheet which is welded to the elastic sheet with a plurality of welds intermittently formed in a predetermined direction and an orthogonal direction perpendicular to the predetermined direction when the elastic sheet is stretched in the predetermined direction, wherein the plurality of welds are long welds having a planar shape whose longitudinal dimension in the orthogonal direction is longer than its width dimension in the predetermined direction, and which are arranged so that the orthogonal distance between two adjacent long welds is wider than the longer of the longitudinal dimensions of the two long welds; and the elastic sheet has a plurality of through-holes which are formed on both sides of the plurality of long welds in the predetermined direction and which penetrate the elastic sheet from front to back.

[0098] According to the present invention, through-holes are formed on both sides of the long weld in a predetermined direction, and the elasticity of the long weld itself is lost by melting during welding. Therefore, when tension is applied in a predetermined direction, a portion of the elastic sheet adjacent to the long weld in the predetermined direction via the through-hole separates from the long weld while maintaining its shape. Here, in this invention, because the longitudinal dimension of the long weld is longer than the width dimension, the distance that the portion of the elastic sheet moves away from the long weld due to tension is longer than when the width dimension is equal to or greater than the longitudinal dimension. Therefore, a relatively large opening area of ​​the through-hole can be ensured when tension is applied.

[0099] On the other hand, when the longitudinal dimension of a long weld is longer than the width dimension, applying tension in a predetermined direction causes stress to concentrate in a portion of the elastic sheet adjacent to the orthogonal end of the long weld, making the elastic sheet more susceptible to tearing at this portion. Furthermore, if a similar tear occurs in another long weld adjacent to the long weld in the orthogonal direction, the elastic sheet will tear so as to connect the two adjacent long welds. In contrast, in the present invention, the orthogonal distance between two orthogonally adjacent long welds is wider than the longer of the longitudinal dimensions of the two long welds, so tearing so as to connect the two adjacent long welds can be suppressed compared to when the distance is equal to or narrower than the longitudinal dimension of the long welds.

[0100] Therefore, according to the present invention, it is possible to prevent the elastic sheet made of a styrene-based elastomer from breaking while also ensuring the breathability of the elastic sheet.

[0101] The longitudinal dimensions of the multiple long welds can all be set to the same, or at least one long weld can be set to a dimension different from the longitudinal dimensions of the other long welds. When different dimensions are set in this way, the set dimension differs for each interval, making it difficult to manage the intervals.

[0102] Therefore, in the elastic sheet, it is preferable that the multiple welds are arranged so that the perpendicular distance between two adjacent long welds in the perpendicular direction is wider than the longest longitudinal dimension of the multiple welds.

[0103] According to the above configuration, the distance between two adjacent long welded portions in the orthogonal direction is set wider than the longest longitudinal dimension of all the long welded portions, making it easier to manage whether the distance dimension is appropriate in the elastic sheet.

[0104] In the stretchable sheet, it is preferable that the multiple welds further include a first long weld, which is one of the two long welds, and another weld adjacent to the specified direction, and that the first long weld and the other weld are arranged so that the distance in the specified direction between the first long weld and the other weld is wider than the longitudinal dimension of the first long weld.

[0105] According to this configuration, the distance in a predetermined direction between the first long welded portion and the other welded portion is wider than the longitudinal dimension of the first long welded portion, so that the area of ​​the elastic sheet between the first long welded portion and the other welded portion can be made relatively large (the stretchable area can be made larger), which reduces the tension applied to the first long welded portion and alleviates stress concentration at both ends of the first long welded portion in the orthogonal direction, thereby more effectively preventing breakage of the elastic sheet.

[0106] In the stretchable sheet, it is preferable that the dimension of the other welded portion in the orthogonal direction is smaller than the longitudinal dimension of the first long welded portion.

[0107] According to this configuration, because the orthogonal dimension of the other welded portion is smaller than the longitudinal dimension of the first long welded portion, the region of the elastic sheet adjacent to the first long welded portion in a predetermined direction (the stretchable region) can be relatively expanded in the predetermined direction compared to when the orthogonal dimension of the other welded portion is equal to or larger than the longitudinal dimension of the first long welded portion, thereby mitigating stress concentration at both ends of the first long welded portion in the orthogonal direction and effectively preventing breakage of the elastic sheet.

[0108] In the elastic sheet, it is preferable that the two long welds include an edge side long weld adjacent to the orthogonal edge of the elastic sheet, and that the edge side long weld is arranged so that the distance from the edge side long weld to the edge of the elastic sheet is greater than the longer of the longitudinal dimensions of the two long welds.

[0109] According to the above configuration, since the distance from the end edge side long welded portion to the end edge of the elastic sheet is longer than the longer of the longitudinal dimensions of the two long welded portions, breakage from the end edge side long welded portion to the end edge can also be effectively suppressed.

[0110] The present invention also provides a manufacturing method for manufacturing the stretchable sheet, which includes melting a thermoplastic resin containing a styrene-based elastomer as a main component, forming a sheet-like intermediate using the melted thermoplastic resin, cooling the intermediate to a temperature range where the intermediate obtains a predetermined elasticity, thereby forming the elastic sheet, applying a predetermined tension to the elastic sheet in the predetermined direction, and forming a plurality of welded portions intermittently in the predetermined direction and the perpendicular direction on the elastic sheet stretched by the tension. and welding the breathable sheet to a sheet, wherein the plurality of welds are a plurality of long welds having a planar shape whose longitudinal dimension in the orthogonal direction is longer than the width dimension in the specified direction, and the plurality of long welds are arranged so that the orthogonal distance between two adjacent long welds in the orthogonal direction is wider than the longer of the longitudinal dimensions of the two long welds, and when forming the plurality of welds on the elastic sheet, a plurality of through holes that penetrate the elastic sheet from front to back are formed on both sides of the specified direction of the plurality of long welds.

[0111] According to the present invention, it is possible to produce a stretchable sheet that can simultaneously prevent breakage of the elastic sheet and ensure breathability of the elastic sheet, as described above. Furthermore, the present invention uses a thermoplastic resin whose main component is a styrene-based elastomer. Therefore, unlike when using a thermoplastic resin whose main component is an olefin-based elastomer, there is no need to leave the cooled intermediate for a predetermined period of time, and the stretchable sheet can be produced from the thermoplastic resin in a continuous process.

Claims

1. A stretchable sheet comprising: an elastic sheet made of a thermoplastic resin whose main component is a styrene-based elastomer; and a breathable sheet which is welded to the elastic sheet with a plurality of welds intermittently formed in a predetermined direction and an orthogonal direction perpendicular to the predetermined direction while the elastic sheet is stretched in the predetermined direction, the breathable sheet having breathability; the plurality of welds are long welds having a planar shape whose longitudinal dimension in the orthogonal direction is longer than its width dimension in the predetermined direction, and which are arranged so that the orthogonal distance between two adjacent long welds is wider than the longer of the longitudinal dimensions of the two long welds; and the elastic sheet has a plurality of through-holes formed on both sides of the plurality of long welds in the predetermined direction and which penetrate the elastic sheet from front to back.

2. The stretchable sheet according to claim 1, wherein the plurality of welded portions are arranged so that the distance in the perpendicular direction between two adjacent long welded portions in the perpendicular direction is wider than the longest longitudinal dimension of the plurality of welded portions.

3. A stretchable sheet according to claim 1 or 2, wherein the plurality of welded portions further includes another welded portion adjacent to one of the two long welded portions in the predetermined direction, and the first long welded portion and the other welded portion are arranged so that the distance in the predetermined direction between the first long welded portion and the other welded portion is wider than the longitudinal dimension of the first long welded portion.

4. The stretchable sheet according to claim 3, wherein the dimension of the other welded portion in the orthogonal direction is smaller than the longitudinal dimension of the first long welded portion.

5. A stretchable sheet as claimed in any one of claims 1 to 4, wherein the two long welded portions include an edge-side long welded portion adjacent to the orthogonal edge of the elastic sheet, and the edge-side long welded portion is positioned so that the distance from the edge-side long welded portion to the edge of the elastic sheet is greater than the longer of the longitudinal dimensions of the two long welded portions.

6. A manufacturing method for producing the stretchable sheet according to any one of claims 1 to 5, comprising: melting a thermoplastic resin containing a styrene-based elastomer as a main component; forming a sheet-like intermediate using the melted thermoplastic resin; cooling the intermediate to a temperature range at which the intermediate achieves a predetermined elasticity, thereby forming the elastic sheet; applying a predetermined tension to the elastic sheet in the predetermined direction; and forming a plurality of welds intermittently in the predetermined direction and the orthogonal direction on the elastic sheet stretched by the tension, thereby welding the breathable sheet to the elastic sheet, wherein the plurality of welds are a plurality of long welds having a planar shape whose longitudinal dimension in the orthogonal direction is longer than its width dimension in the predetermined direction, and the plurality of long welds are arranged so that the distance in the orthogonal direction between two long welds adjacent to each other in the orthogonal direction is wider than the longer of the longitudinal dimensions of the two long welds. A method for manufacturing an elastic sheet, wherein when forming the multiple welded portions in the elastic sheet, multiple through-holes that penetrate the elastic sheet from front to back are formed on both sides of the multiple long welded portions in the specified direction.

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