Underpants-type absorbent article
Patent Information
- Application Number
- PCT/JP2026/004369
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-28
- Filing Date
- 2026-02-06
- Publication Date
- 2026-10-01
Smart Images
Figure JP2026004369_01102026_PF_FP_ABST
Abstract
Description
Pants-type absorbent article
[0001] The present disclosure relates to a pants-type absorbent article.
[0002] Conventionally, pants-type absorbent articles in which side seal regions on both widthwise sides of a front body and a back body are joined are known (see, for example, Patent Document 1 and Patent Document 2). The side seal regions are generally joined by ultrasonic welding, heat welding, or the like. In this process, the pants-type absorbent article is inserted between an anvil having convex portions shaped to form a seal pattern and a horn movable forward and backward relative to the anvil. As the anvil rotates, the convex portions come into contact with the side seal regions, and the side seal regions are sandwiched between the convex portions and the horn to form the seal pattern.
[0003] Here, the pants-type absorbent article disclosed in Patent Document 1 has a plurality of seal patterns each formed in a rectangular shape elongated in the width direction. The plurality of seal patterns are intermittently arranged along the longitudinal direction to form a row, and are arranged side by side along the width direction. At this time, in each of the left and right seal rows, the end positions of the respective seal patterns in the width direction are aligned.
[0004] Further, the pants-type absorbent article disclosed in Patent Document 2 has a plurality of seal patterns formed in a triangular shape or a semicircular shape that gradually becomes longer in the longitudinal direction toward the center in the width direction. Each seal pattern has one side extending in the longitudinal direction. Furthermore, the plurality of seal patterns are intermittently arranged along the longitudinal direction to form a row. A line segment connecting the longitudinally extending sides of the respective seal patterns at the shortest distance forms a single straight line. Furthermore, the rows of seal patterns exist on both left and right sides of the straight line.
[0005] Japanese Patent Application Laid-Open No. 2013-146549 Japanese Patent Application Laid-Open No. 2013-42861
[0006] Incidentally, the seal pattern formed in the side seal region is formed gradually along the width direction of the product. If, for example, a linear pressure exceeding a predetermined value acts on the horn during the formation of the seal pattern, or if the linear pressure acting on the horn suddenly increases, the load on the horn will increase, which may cause the welding device to malfunction. Therefore, if the welding device determines that the load on the horn is high, it controls the horn to retract relative to the anvil to reduce the linear pressure.
[0007] In contrast, the seal pattern disclosed in Patent Document 1 has the widthwise end positions of multiple seal patterns aligned in each seal row. Furthermore, the vertical length of each seal pattern is constant along its entire width. Therefore, the linear pressure acting on the horn when forming the seal pattern does not fluctuate from the start to the end of seal pattern formation, reaching its maximum linear pressure. In other words, the linear pressure increases rapidly from zero (no linear pressure) to the maximum linear pressure at the start of seal pattern formation. As a result, the welding device may determine that the load on the horn is high immediately after seal pattern formation begins and may retract the horn relative to the anvil. This may result in the seal pattern not being properly formed and the side seal region not being stably welded.
[0008] Furthermore, in the seal pattern disclosed in Patent Document 2, the left and right rows of seal patterns lie on a straight line formed by the shortest distance between the vertically extending sides of each seal pattern. In other words, in the side seal region, the straight portion that forms the boundary between the left and right rows of seal patterns is the part that is welded with the maximum linear pressure. However, because the part that is welded with the maximum linear pressure is a straight line, the area in the width direction is small, which presents a problem in that it is difficult to ensure the welding strength of the side seal region.
[0009] This disclosure addresses the above-mentioned problems and aims to provide a pant-type absorbent article that can stably weld the side seal region while ensuring welding strength.
[0010] To achieve the above objective, the absorbent pants of the present disclosure are formed by connecting the ventral portion, crotch portion, and dorsal portion in this order in a continuous manner, and have a side seal region in which the sides of the ventral portion and the sides of the dorsal portion overlap and are joined, and a waist opening and a pair of leg openings are formed. The side seal region has a plurality of seal patterns that have a predetermined length in the width direction and are intermittently arranged along a longitudinal direction perpendicular to the width direction, and when a virtual straight line is set in the side seal region along the longitudinal direction, the virtual straight line overlaps with at least one of the seal patterns, and all seal patterns are present in at least a part of the central region located in the middle of the width direction of the side seal region and having a predetermined length in the width direction, and the total area of the seal patterns in the central region is larger than the total area of the seal patterns in the inner region in the width direction inward from the central region, and the total area of the seal patterns in the outer region in the width direction outward from the central region.
[0011] As a result, the pant-type absorbent article of this disclosure can stably weld the side seal area and ensure welding strength.
[0012] This is a schematic diagram showing a disposable diaper being worn by a wearer. This is an enlarged schematic diagram showing a portion of the left side seal area of the disposable diaper of this embodiment. This diagram shows the relationship between each region in the side seal area of this embodiment and the total area of the seal pattern present in each region. This is an explanatory diagram showing the method of joining the side seal areas. This diagram shows the relationship between the widthwise position and linear pressure of the side seal area in the disposable diaper of this embodiment. This is an enlarged schematic diagram showing a portion of the left side seal area of the disposable diaper of Example 1. This diagram shows the relationship between the widthwise position and linear pressure of the side seal area in the disposable diaper of Example 1. This is an enlarged schematic diagram showing a portion of the left side seal area of the disposable diaper of Example 2. This diagram shows the relationship between the widthwise position and linear pressure of the side seal area in the disposable diaper of Example 2. This is an enlarged schematic diagram showing a portion of the left side seal area of the disposable diaper of Example 3. This diagram shows the relationship between the widthwise position and linear pressure of the side seal area in the disposable diaper of Example 3. This is an enlarged schematic diagram showing a portion of the left side seal area of the disposable diaper of Example 4.
[0013] The embodiments for implementing the pant-type absorbent article described herein are explained below based on the drawings. In the following explanation, the direction corresponding to the front-to-back direction of the wearer M is referred to as the "front-to-back direction N," and the direction perpendicular to the front-to-back direction N and corresponding to the width direction of the wearer M is referred to as the "width direction W." Furthermore, the front-to-back direction N, the left-to-right direction of the width direction W, and the up-to-down direction of the vertical direction H (described later) are all based on the direction as seen from the wearer M.
[0014] The disposable diaper 1 shown in Figure 1 is an example of a pant-type absorbent article according to the present disclosure. The disposable diaper 1 has an abdominal portion 10, a crotch portion 20, and a back portion 30 that are continuously connected in this order along the front-to-back direction N. The disposable diaper 1 has a left side seal region 40 on the left side in the width direction W, where the left side portion 11 of the abdominal portion 10 in the width direction W and the left side portion 31 of the back portion 30 in the width direction W are joined together. The disposable diaper 1 also has a right side seal region 40 on the right side in the width direction W, where the right side portion 12 of the abdominal portion 10 in the width direction W and the right side portion 32 of the back portion 30 in the width direction W are joined together.
[0015] The ventral portion 10 and the dorsal portion 30 are connected in the circumferential direction R by the left and right side seal regions 40, forming a cylindrical waist portion 2. The waist portion 2 has a waist opening P1 at its upper end that surrounds the torso of the wearer M. The waist opening P1 is formed by the edges of the ventral portion 10 and the dorsal portion 30. Furthermore, with the formation of the waist portion 2, a pair of leg openings P2 are formed on both sides of the crotch portion 20 in the width direction W. As a result, the disposable diaper 1 as a whole has a pant-like shape.
[0016] The waist opening P1 is an opening through which the wearer M passes over the torso when the wearer M is wearing the disposable diaper 1. The pair of leg openings P2 are openings through which the wearer M passes over the legs when the wearer M is wearing the disposable diaper 1. When the wearer M is wearing the disposable diaper 1, the abdominal portion 10 covers the lower abdomen of the wearer M, the dorsal portion 30 covers the buttocks of the wearer M, and the crotch portion 20 covers the crotch of the wearer M. An absorbent material is provided on the inside of the crotch portion 20 to absorb bodily fluids such as urine.
[0017] Furthermore, the left and right side seal regions 40 are joined together by ultrasonic welding using an ultrasonic welding device, forming multiple seal patterns 50. The seal pattern 50 formed in the left side seal region 40 and the seal pattern 50 formed in the right side seal region 40 are formed symmetrically in the width direction W. Therefore, the seal pattern 50 formed in the left side seal region 40 will be described below, and the seal pattern 50 formed in the right side seal region 40 will not be described.
[0018] As shown in Figure 2, each of the multiple seal patterns 50 is formed in a rectangular shape having a predetermined length in the width direction W. Each seal pattern 50 is the same size. The multiple seal patterns 50 are arranged side by side with a certain gap between them, along the direction in which the side seal region 40 extends, i.e., along the vertical direction H.
[0019] The widthwise length W of each seal pattern 50 (hereinafter referred to as "width dimension W1") is shorter than the widthwise length W2 of the side seal region 40. Furthermore, the multiple seal patterns 50 are arranged along the entire length of the vertical direction H of the side seal region 40 (see Figure 1). Additionally, the spacing between the multiple seal patterns 50 in the vertical direction H does not necessarily have to be constant. Moreover, the seal patterns 50 may be arranged without any spacing in the vertical direction H.
[0020] The length W2 in the width direction W of the side seal region 40 refers to the distance along the width direction W from the innermost end of the seal pattern 50 in the width direction W (hereinafter referred to as "innermost end 50a") to the outermost end of the seal pattern 50 in the width direction W (hereinafter referred to as "outermost end 50b"). The "innermost end 50a" of the seal pattern 50 in the width direction is the position of a virtual straight line that passes through the inner edge in the width direction W of the seal pattern 50 formed on the innermost side (towards the center of the width direction W) among the multiple seal patterns 50 formed in the side seal region 40, and extends in the vertical direction H. The "outermost end 50b" of the seal pattern 50 in the width direction is the position of a virtual straight line that passes through the outer edge in the width direction W of the seal pattern 50 formed on the outermost side (outside the width direction W) among the multiple seal patterns 50 formed in the side seal region 40, and extends in the vertical direction H.
[0021] Furthermore, when a single linear virtual line K is set in the side seal region 40 along the vertical direction H, this virtual line K coincides with at least one seal pattern 50 at any position in the width direction W of the side seal region 40. In other words, when the side seal region 40 is viewed along the vertical direction H, a seal pattern 50 exists in at least a portion of the vertical direction H.
[0022] Furthermore, the side seal region 40 is virtually divided into a central region 41, an inner region 42, and an outer region 43. The central region 41 is the middle region of the side seal region 40 in the width direction W. The inner region 42 is the region of the side seal region 40 that is inward in the width direction from the central region 41, that is, the region from the innermost end 50a in the width direction of the seal pattern 50 to the central region 41. The outer region 43 is the region of the side seal region 40 that is outward in the width direction from the central region 41, that is, the region from the outermost end 50b in the width direction of the seal pattern 50 to the central region 41. Note that the central region 41, the inner region 42, and the outer region 43 all extend along the entire length H of the side seal region 40.
[0023] The central region 41, the inner region 42, and the outer region 43 each have a predetermined length in the width direction W. Here, the length W21 of the central region 41, the length W22 of the inner region 42, and the length W23 of the outer region 43 are set to the same length. Note that the lengths W21, W22, and W23 of the central region 41, inner region 42, and outer region 43 in the width direction W do not necessarily have to be the same length and can be set arbitrarily.
[0024] In contrast, the multiple seal patterns 50 include a first pattern 51 and a second pattern 52, each having a different position in the width direction W.
[0025] The first pattern 51 is a seal pattern 50 formed across the inner region 42 and the central region 41. Here, the first pattern 51 extends continuously from the inner end in the width direction of the inner region 42, i.e., the innermost end 50a in the width direction of the seal pattern 50, to the outer end 41b in the width direction of the central region 41. Therefore, the length of the first pattern 51 in the width direction W (width direction length W1) is the sum of the length W21 of the central region 41 in the width direction W and the length W22 of the inner region 42 in the width direction W.
[0026] Furthermore, the second pattern 52 is a seal pattern 50 formed across the outer region 43 and the central region 41. Here, the second pattern 52 extends continuously from the inner end 41a in the width direction of the central region 41 to the outer end in the width direction of the outer region 43, that is, to the outermost end 50b in the width direction of the seal pattern 50. Therefore, the length of the second pattern 52 in the width direction W (width direction length W1) is the sum of the length W21 in the width direction of the central region 41 and the length W23 in the width direction of the outer region 43.
[0027] The first pattern 51 and the second pattern 52 are arranged alternately along the vertical direction H. As a result, both the first pattern 51 and the second pattern 52 are present in the central region 41. In other words, all the seal patterns 50 formed in the side seal region 40 are present in the central region 41.
[0028] Furthermore, in the first pattern 51, half (part) of the seal pattern 50 is present in the inner region 42, but not in the outer region 43. On the other hand, in the second pattern 52, half (part) of the seal pattern 50 is present in the outer region 43, but not in the inner region 42. In other words, half of the seal pattern 50 formed in the side seal region 40 (first pattern 51) is present in the inner region 42. Similarly, half of the seal pattern 50 formed in the side seal region 40 (second pattern 52) is present in the outer region 43. Since the first pattern 51 and the second pattern 52 are arranged alternately along the vertical direction H, when viewed along the vertical direction H, blank areas 44 where no seal pattern 50 is present are generated at regular intervals in the inner region 42 and the outer region 43.
[0029] Furthermore, as shown in Figure 3, the total area of the seal pattern 50 in the central region 41 is larger than the total area of the seal pattern 50 in the inner region 42 and the total area of the seal pattern 50 in the outer region 43. Here, since the lengths W21, W22, and W23 in the width direction W of the central region 41, inner region 42, and outer region 43 are the same length, and the first pattern 51 and the second pattern 52 are the same size, the total area of the seal pattern 50 in the inner region 42 and the total area of the seal pattern 50 in the outer region 43 is half the total area of the seal pattern 50 in the central region 41.
[0030] The function of the disposable diaper 1 of this embodiment is described below.
[0031] The ultrasonic welding device for joining the side seal area 40 of the disposable diaper 1, as shown in Figure 4, comprises a block-shaped horn 101 and a cylindrical anvil 102. An ultrasonic vibrator 103 is attached to the horn 101. The anvil 102 has a convex portion 102a formed on its circumferential surface 102b that is shaped like a seal pattern 50. The convex portion 102a is shaped so that the width direction W of the disposable diaper 1 coincides with the circumferential direction of the anvil 102. The horn 101 and the anvil 102 are positioned with the pressing surface 101a of the horn 101 and the circumferential surface 102b of the anvil 102 facing each other, and the circumferential surface 102b rotates relative to the pressing surface 101a. The horn 101 also moves closer to and away from the anvil 102.
[0032] Then, in order to join the side seal region 40 using the ultrasonic welding device, first, the disposable diaper 1 is folded in the middle in the front-to-back direction N, and the ventral portion 10 and the dorsal portion 30 are overlapped. At this time, the disposable diaper 1 is in a continuous (connected) state with other disposable diapers 1 along the width direction W. Next, the disposable diaper 1 is fed between the horn 101 and the anvil 102. The feeding direction of the disposable diaper 1 by the ultrasonic welding device coincides with the width direction W of the disposable diaper.
[0033] Then, the portion of the disposable diaper 1 corresponding to the side seal region 40 is pressurized between the protrusion 102a and the horn 101, and heated by ultrasonic vibration energy transmitted from the horn 101. As a result, the portion of the disposable diaper 1 in contact with the protrusion 102a melts, forming a seal pattern 50 in the side seal region 40, and the side seal region 40 is joined. After the side seal region 40 is joined, the disposable diapers 1 are separated one by one.
[0034] Here, since the feeding direction of the disposable diaper 1 by the ultrasonic welding device coincides with the width direction W of the disposable diaper 1, the seal pattern 50 is formed along the width direction W. Also, since the disposable diaper 1 is fed to the ultrasonic welding device in a continuous state, the seal pattern 50 may be formed gradually from the innermost end 50a in the width direction toward the outermost end 50b, or it may be formed gradually from the outermost end 50b in the width direction toward the innermost end 50a.
[0035] When the seal pattern 50 is formed from the innermost end 50a in the width direction toward the outermost end 50b in the width direction, the protrusions 102a make contact in the order of the inner region 42, the central region 41, and the outer region 43. Therefore, in this case, the first pattern 51 is formed first. Also, when the seal pattern 50 is formed from the outermost end 50b in the width direction toward the innermost end 50a in the width direction, the protrusions 102a make contact in the order of the outer region 43, the central region 41, and the inner region 42. Therefore, in this case, the second pattern 52 is formed first.
[0036] Furthermore, when the side seal region 40 is joined, a linear pressure acts on the horn 101 during the period from the start to the end of the formation of the seal pattern 50. The "linear pressure" is indicated by the joining ratio of the side seal region 40 when viewed along the longitudinal direction H. In other words, the linear pressure is indicated by the total length (area) of the portion where the virtual straight line K shown in Figure 2 overlaps with the seal pattern 50.
[0037] When the side seal region 40 is viewed along the vertical direction H, the more of the side seal region 40 that is joined, that is, the more seal patterns 50 that exist, the larger the total length (area) of the portion where the virtual straight line K overlaps with the seal pattern 50. In this case, the joining rate of the side seal region 40 is high, and the linear pressure is high.
[0038] Furthermore, when the side seal region 40 is viewed along the vertical direction H, the less of the side seal region 40 is joined, that is, the less of the seal pattern 50 that exists, the shorter (smaller) the total length (area) of the portion where the virtual straight line K overlaps with the seal pattern 50. In this case, the joining rate of the side seal region 40 is low, and the linear pressure is low. Note that if the side seal region 40 is not joined, the joining rate becomes zero, and the linear pressure also becomes zero.
[0039] In contrast, all of the sealing patterns 50 are present in the central region 41, while half of the sealing patterns 50 are present in the inner region 42 and the outer region 43. The total area of the sealing patterns 50 in the central region 41 is larger than the total area of the sealing patterns 50 in the inner region 42 and the total area of the sealing patterns 50 in the outer region 43 (see Figure 3).
[0040] Therefore, when joining the side seal region 40, as shown in Figure 5, the linear pressure acting on the horn 101 is higher (maximum linear pressure) during the period when the anvil 102 is in contact with the central region 41 compared to the period when the anvil 102 is in contact with the inner region 42. Also, during the period when the anvil 102 is in contact with the central region 41, the linear pressure acting on the horn 101 is higher (maximum linear pressure) compared to the period when the anvil 102 is in contact with the outer region 43.
[0041] Therefore, in the disposable diaper 1 of this embodiment, the linear pressure acting on the horn 101 does not reach its maximum linear pressure at the timing of the start of formation of the seal pattern 50, and a rapid increase in linear pressure immediately after the start of formation of the seal pattern 50 can be suppressed.
[0042] Furthermore, when the virtual straight line K is set in the side seal region 40, the virtual straight line K overlaps at least one seal pattern 50 at any position in the width direction W of the side seal region 40. That is, when the side seal region 40 is viewed along the longitudinal direction H, the seal pattern 50 is present in at least a portion thereof. Therefore, in the side seal region 40, no region where the line pressure becomes zero can occur when viewed along the longitudinal direction H. Further, the line pressure acting on the horn 101 increases stepwise without interruption from the inner region 42 toward the central region 41 to reach the maximum line pressure. Furthermore, the line pressure acting on the horn 101 increases stepwise without interruption from the outer region 43 toward the central region 41 to reach the maximum line pressure. That is, the disposable diaper 1 can suppress the amount of change when the line pressure acting on the horn 101 increases during the formation of the seal pattern 50.
[0043] This prevents the ultrasonic welding device from determining that the load applied to the horn 101 is high immediately after the start of formation of the seal pattern 50 or during the formation of the seal pattern 50. Therefore, in the disposable diaper 1, it is possible to suppress the control that causes the horn 101 to retract relative to the anvil 102. As a result, with the disposable diaper 1, an appropriate seal pattern 50 can be formed, and the side seal region 40 can be stably welded.
[0044] Further, in the disposable diaper 1, all the seal patterns 50 are present, and the central region 41 where the line pressure acting on the horn 101 reaches the maximum line pressure has a predetermined length W21 in the width direction W. In other words, in the side seal region 40, the portion welded at the maximum line pressure (the central region 41) has the predetermined length W21 in the width direction W. Therefore, compared to the case where the central region 41 is linear, the disposable diaper 1 can improve the welding strength of the side seal region 40 and ensure the welding strength of the side seal region 40.
[0045] Therefore, the disposable diaper 1 can stably weld the side seal region 40 by the seal pattern 50 formed along the product width direction, and ensure the welding strength.
[0046] Further, the disposable diaper 1 of the present embodiment has a first pattern 51 formed across an inner region 42 and a central region 41, and a second pattern 52 formed across an outer region 43 and the central region 41. In contrast, the lengths W21, W22, and W23 in the width direction W of the central region 41, the inner region 42, and the outer region 43 are the same, and the first pattern 51 and the second pattern 52 have the same size.
[0047] Therefore, for example, one first pattern 51 and one second pattern 52 constitute a pattern group 53 that is point-symmetrical about a symmetry point X set on the center line O (see Fig. 2). The "center line O" is a virtual straight line set at the center position in the width direction W of the side seal region 40 and extending in the longitudinal direction H. Further, the "symmetry point X" is set at the center position in the longitudinal direction H of the first pattern 51 and the second pattern 52 that constitute the pattern group 53.
[0048] Accordingly, in the disposable diaper 1, the amount of change in linear pressure from the start of forming the seal pattern 50 to reaching the maximum linear pressure, and the amount of change in linear pressure from the maximum linear pressure to the end of forming the seal pattern 50 can be made the same. For this reason, fluctuations in the linear pressure applied to the horn 101 when forming the seal pattern 50 can be suppressed, and the load on the horn 101 can be reduced. Further, since the seal patterns 50 are arranged point-symmetrically, even when the side seal regions 40 are joined in a state where the disposable diapers 1 are continuous, the change in linear pressure when joining the side seal regions 40 between adjacent products can be made the same. In addition, the appearance of the side seal region 40 can be made the same between adjacent products.
[0049] Furthermore, in the disposable diaper 1, the plurality of seal patterns 50 can be made to appear meandering in the longitudinal direction H about the center line O. Therefore, the appearance of the side seal region 40 can be improved.
[0050] (Example 1) In the disposable diaper 1A according to Example 1 shown in Fig. 6, a side seal region 40A is virtually partitioned into a central region 61, a first inner region 62A, a second inner region 62B, a first outer region 63A, and a second outer region 63B.
[0051] The central region 61 is the middle region in the width direction W of the side seal region 40A. The first inner region 62A is the innermost region in the width direction of the side seal region 40A. The second inner region 62B is the region of the side seal region 40A between the central region 61 and the first inner region 62A. The first outer region 63A is the outermost region in the width direction of the side seal region 40A. The second outer region 63B is the region of the side seal region 40A between the central region 61 and the first outer region 63A. The length in the width direction W of the central region 61, the first inner region 62A, the second inner region 62B, the first outer region 63A, and the second outer region 63B are the same in this case. Note that the length in the width direction W of each region 61 to 63B does not necessarily have to be the same and can be set arbitrarily.
[0052] In contrast, the multiple seal patterns 50A are all the same size and consist of a first pattern 65, a second pattern 66, and a third pattern 67, which are formed in different positions.
[0053] The first pattern 65 is a seal pattern 50A formed spanning from the first inner region 62A to the central region 61. Here, the first pattern 65 extends continuously from the inner end in the width direction of the first inner region 62A (the innermost end 50a in the width direction of the seal pattern 50A) to the outer end 61b in the width direction of the central region 61.
[0054] The second pattern 66 is a seal pattern 50A formed spanning from the second inner region 62B to the second outer region 63B. Here, the second pattern 66 extends continuously from the widthwise inner end 62x of the second inner region 62B to the widthwise outer end 63x of the second outer region 63B.
[0055] The third pattern 67 is a seal pattern 50A formed spanning from the central region 61 to the first outer region 63A. Here, the third pattern 67 extends continuously from the inner end 61a in the width direction of the central region 61 to the outer end in the width direction of the first outer region 63A (the outermost end 50b in the width direction of the seal pattern 50A).
[0056] The seal pattern 50A is composed of multiple pattern groups 69 arranged in the vertical direction H, with four seal patterns 50A arranged from top to bottom in the order of first pattern 65, second pattern 66, third pattern 67, and second pattern 66.
[0057] As a result, in the disposable diaper 1A of Example 1, when viewed along the vertical direction H, the number of patterns present in each region, when counted per pattern group 69, is "4" in the central region 61, "1" in the first inner region 62A and the first outer region 63A, and "3" in the second inner region 62B and the second outer region 63B.
[0058] As a result, as shown in Figure 7, the linear pressure acting on the horn 101 when joining the side seal region 40A increases in two stages along the width direction W from one side to the other, reaching a maximum linear pressure in the central region 61. Then, the linear pressure decreases in two stages along the width direction W toward the other side. Therefore, the disposable diaper 1A can increase the linear pressure more gradually compared to the example shown in Figure 5, for example. This allows the disposable diaper 1A to suppress the load on the horn 101 and to form the seal pattern 50A more appropriately.
[0059] (Example 2) In the disposable diaper 1B of Example 2 shown in Figure 8, the side seal area 40B is virtually divided into a central area 71, a first inner area 72A, a second inner area 72B, a first outer area 73A, and a second outer area 73B.
[0060] The central region 71 is the middle region of the side seal region 40B in the width direction W. The first inner region 72A is the innermost region of the side seal region 40B in the width direction. The second inner region 72B is the region of the side seal region 40B between the central region 71 and the first inner region 72A. The first outer region 73A is the outermost region of the side seal region 40B in the width direction. The second outer region 73B is the region of the side seal region 40B between the central region 71 and the first outer region 73A. Note that the lengths in the width direction W of the central region 71, the second inner region 72B, and the second outer region 73B are the same in this case. Also, the length in the width direction W of the first inner region 72A and the first outer region 73A is shorter than that of the central region 71, etc. However, the lengths in the width direction W of the central region 71, the second inner region 72B, and the second outer region 73B do not necessarily have to be the same. Furthermore, the widthwise length W of the first inner region 72A and the first outer region 73A does not necessarily have to be shorter than that of the central region 71, etc. In other words, the widthwise length W of each region 71 to 73B can be set arbitrarily.
[0061] In contrast, the multiple seal patterns 50B are all the same size and consist of a first pattern 75 and a second pattern 76, which are formed in different positions.
[0062] The first pattern 75 is a seal pattern 50B formed spanning from the first inner region 72A to the central region 71. Here, the first pattern 75 extends continuously from the inner end in the width direction of the first inner region 72A (the innermost end 50a in the width direction of the seal pattern 50B) to the outer end 71b in the width direction of the central region 71. Furthermore, the first pattern 75 gradually curves in an arc towards the end of the innermost end 50a in the width direction. As a result, the area of the first pattern 75 along the vertical direction H gradually decreases from the central region 71 towards the innermost end 50a in the width direction, which is the innermost end in the width direction.
[0063] The second pattern 76 is a seal pattern 50B formed spanning from the central region 71 to the first outer region 73A. Here, the second pattern 76 extends continuously from the inner end 71a in the width direction of the central region 71 to the outer end in the width direction of the first outer region 73A (the outermost end 50b in the width direction of the seal pattern 50B). Furthermore, the second pattern 76 gradually curves in an arc towards the outermost end 50b in the width direction. As a result, the area of the second pattern 76 along the vertical direction H gradually decreases from the central region 71 towards the outermost end 50b in the width direction, which is the outermost end in the width direction.
[0064] Furthermore, the first pattern 75 and the second pattern 76 are arranged alternately along the vertical direction H.
[0065] As a result, in the disposable diaper 1B of Example 2, the total area of the seal pattern 50B increases as it approaches the central region 71 in the first inner region 72A and the second inner region 72B. Similarly, in the first outer region 73A and the second outer region 73B, the total area of the seal pattern 50B increases as it approaches the central region 71. Therefore, as shown in Figure 9, the linear pressure acting on the horn 101 in the first inner region 72A, the second inner region 72B, the first outer region 73A, and the second outer region 73B gradually increases as it approaches the central region 71.
[0066] As a result, the disposable diaper 1B of Example 2 can gradually increase the linear pressure acting on the horn 101 from the timing of the start of formation of the seal pattern 50B. Furthermore, the disposable diaper 1B can stably form the seal pattern 50B by slowing down the increase in load on the horn 101.
[0067] (Example 3) In the disposable diaper 1C of Example 3 shown in Figure 10, the side seal region 40C is virtually divided into a central region 81, a first inner region 82A, a second inner region 82B, a first outer region 83A, and a second outer region 83B.
[0068] The central region 81 is the middle region of the side seal region 40C in the width direction W. The first inner region 82A is the innermost region of the side seal region 40C in the width direction. The second inner region 82B is the region of the side seal region 40C between the central region 81 and the first inner region 82A. The first outer region 83A is the outermost region of the side seal region 40C in the width direction. The second outer region 83B is the region of the side seal region 40C between the central region 81 and the first outer region 83A. The length in the width direction W of the central region 81, the first inner region 82A, the second inner region 82B, the first outer region 83A, and the second outer region 83B are the same in this case. Note that the length in the width direction W of each region 81 to 83B does not necessarily have to be the same and can be set arbitrarily.
[0069] In contrast, the multiple seal patterns 50C include a first pattern 85, a second pattern 86, a third pattern 87, and a fourth pattern 88, each having a different length in the width direction W and being formed at a different location.
[0070] The first pattern 85 is a seal pattern 50C formed spanning from the first inner region 82A to the central region 81. Here, the first pattern 85 extends continuously from the inner end in the width direction of the first inner region 82A (the innermost end 50a in the width direction of the seal pattern 50C) to the outer end 81b in the width direction of the central region 81. Therefore, the widthwise length W85 of the first pattern 85 is the sum of the widthwise lengths of the first inner region 82A, the second inner region 82B, and the central region 81.
[0071] The second pattern 86 is a seal pattern 50C formed spanning from the second inner region 82B to the first outer region 83A. Here, the second pattern 86 extends continuously from the widthwise inner end 82x of the second inner region 82B to the widthwise outer end of the first outer region 83A (the widthwise outermost end 50b of the seal pattern 50C). Therefore, the widthwise length W86 of the second pattern 86 is the sum of the widthwise lengths of the second inner region 82B, the central region 81, the second outer region 83B, and the first outer region 83A. In other words, the widthwise length W86 of the second pattern 86 is longer than the widthwise length W85 of the first pattern 85.
[0072] The third pattern 87 is a seal pattern 50C formed spanning from the first inner region 82A to the second outer region 83B. Here, the third pattern 87 extends continuously from the widthwise inner end of the first inner region 82A (the widthwise innermost end 50a of the seal pattern 50C) to the widthwise outer end 83x of the second outer region 83B. Therefore, the widthwise length W87 of the third pattern 87 is the sum of the widthwise lengths of the first inner region 82A, the second inner region 82B, the central region 81, and the second outer region 83B. In other words, the widthwise length W87 of the third pattern 87 is longer than the widthwise length W85 of the first pattern 85 and the same as the widthwise length W86 of the second pattern 86.
[0073] The fourth pattern 88 is a seal pattern 50C formed spanning from the central region 81 to the first outer region 83A. Here, the fourth pattern 88 extends continuously from the widthwise inner end 81a of the central region 81 to the widthwise outer end of the first outer region 83A (the widthwise outermost end 50b of the seal pattern 50C). Therefore, the widthwise length W88 of the fourth pattern 88 is the sum of the widthwise lengths of the central region 81, the second outer region 83B, and the first outer region 83A. In other words, the widthwise length W88 of the fourth pattern 88 is the same as the widthwise length W85 of the first pattern 85.
[0074] The seal pattern 50C is composed of multiple pattern groups 89 arranged in the vertical direction H, with four seal patterns 50C arranged from top to bottom in the order of first pattern 85, second pattern 86, third pattern 87, and fourth pattern 88.
[0075] As a result, in the disposable diaper 1C of Example 3, when viewed along the vertical direction H, the number of patterns present in each region, when counted per pattern group 89, is "4" in the central region 81, "2" in the first inner region 82A and the first outer region 83A, and "3" in the second inner region 82B and the second outer region 83B.
[0076] As a result, as shown in Figure 11, the linear pressure acting on the horn 101 when joining the side seal region 40C increases more gradually compared to the example shown in Figure 5. This allows the disposable diaper 1C to suppress the load on the horn 101 and to form the seal pattern 50C more appropriately.
[0077] (Example 4) In the disposable diaper 1D of Example 4 shown in Figure 12, the side seal region 40D is virtually divided into a central region 91, a first inner region 92A, a second inner region 92B, a first outer region 93A, and a second outer region 93B.
[0078] The central region 91 is the middle region of the side seal region 40D in the width direction W. The first inner region 92A is the innermost region of the side seal region 40D in the width direction. The second inner region 92B is the region of the side seal region 40D between the central region 91 and the first inner region 92A. The first outer region 93A is the outermost region of the side seal region 40D in the width direction. The second outer region 93B is the region of the side seal region 40D between the central region 91 and the first outer region 93A. In this case, the length of the width direction W of each region is longest for the central region 91, and shortest for the second inner region 92B and the second outer region 93B. In this case, the length of the width direction W of the first inner region 92A and the first outer region 93A is shorter than that of the central region 91, and longer than that of the second inner region 92B and the second outer region 93B. However, the length W in the width direction of each region 91-93B is not limited to this and can be set arbitrarily.
[0079] In contrast, the multiple seal patterns 50D include a first pattern 95, a second pattern 96, a third pattern 97, and a fourth pattern 98, each having a different length in the width direction W and being formed at a different location.
[0080] The first pattern 95 is a seal pattern 50D formed spanning from the first inner region 92A to the central region 91. Here, the first pattern 95 is composed of two elliptical patterns aligned in the width direction W. In other words, the first pattern 95 is interrupted at an intermediate position in the width direction W and is divided into two along the width direction W.
[0081] The second pattern 96 is an elliptical seal pattern 50D formed across the second inner region 92B and the central region 91.
[0082] The third pattern 97 is a seal pattern 50D formed spanning from the central region 91 to the first outer region 93A. Here, the third pattern 97 is composed of two elliptical patterns aligned in the width direction W. In other words, the third pattern 97 is interrupted at an intermediate position in the width direction W and is divided into two along the width direction W.
[0083] The fourth pattern 98 is an elliptical seal pattern 50D formed across the central region 91 and the second outer region 93B.
[0084] The seal pattern 50D is composed of multiple pattern groups 99 arranged in the vertical direction H, with four seal patterns 50D arranged from top to bottom in the order of the first pattern 95, the second pattern 96, the third pattern 97, and the fourth pattern 98.
[0085] Thus, in the disposable diaper 1D of Example 4, the first pattern 95 and the third pattern 97 of the sealing pattern 50D are divided in the width direction W. As a result, the disposable diaper 1D can have weaker adhesive strength due to the first pattern 95 and the third pattern 97 compared to, for example, the rectangular pattern shown in Figure 2 and Figure 10.
[0086] Therefore, when removing the disposable diaper 1D, the side seal area 40D can be easily torn along the vertical direction H.
[0087] In disposable diaper 1D, the first pattern 95 is divided, so a second pattern 96 is provided in the region where the seal pattern 50D does not exist when viewed along the vertical direction H. Also, the third pattern 97 is divided, so a fourth pattern 98 is provided in the region where the seal pattern 50D does not exist when viewed along the vertical direction H. As a result, in disposable diaper 1D as well, when viewed along the vertical direction H, there can be no region in the side seal region 40D where the linear pressure is zero. The linear pressure acting on the horn 101 increases stepwise without interruption from the first inner region 92A and the second inner region 92B to the central region 91, or from the first outer region 93A and the second outer region 93B to the central region 91.
[0088] As a result, in the disposable diaper 1D of Example 4, the ultrasonic welding device prevents the load on the horn 101 from being judged as high immediately after the start of formation of the seal pattern 50D or during the formation of the seal pattern 50D. Consequently, the disposable diaper 1D can properly form the seal pattern 50D and stably weld the side seal region 40D.
[0089] While the disposable diapers of this disclosure are described above, their specific configuration is not limited to those described above. Modifications and additions to the design of the disposable diapers of this disclosure are permitted, as long as they do not deviate from the gist of the invention as described in each claim.
[0090] In the above-described embodiment, an example was shown in which the first pattern 51 extends continuously from the innermost end 50a in the width direction of the seal pattern 50 to the outermost end 41b in the width direction of the central region 41, and the second pattern 52 extends continuously from the inner end 41a in the width direction of the central region 41 to the outermost end 50b in the width direction of the seal pattern 50. In other words, an example was shown in which all of the seal patterns 50 are present throughout the entire central region 41.
[0091] However, it is sufficient that all the seal patterns 50 formed in the side seal region 40 are present in at least a portion of the central region 41. In other words, it is sufficient that the central region 41 has at least a portion of an area where all the seal patterns 50 are present, and that when the central region 41 is viewed along the vertical direction H, all the seal patterns 50 overlap in at least a portion of the area. For example, the first pattern 51 may be formed between the innermost end 50a in the width direction and the midpoint of the width direction W of the central region 41, and the second pattern 52 may be formed between the midpoint of the width direction W of the central region 41 and the outermost end 50b in the width direction.
[0092] Furthermore, in the above-described embodiment 3, first patterns 85 to fourth patterns 88 with different lengths in the width direction W were disclosed. However, each of the patterns 85 to 88 may also be set to a different length in the vertical direction H.
[0093] Furthermore, in the disposable diaper 1D of the above-described embodiment 4, the first pattern 95 and the third pattern 97 are divided in the width direction W, while the second pattern 96 and the fourth pattern 98 are not divided. However, when a virtual straight line K extending along the vertical direction H is set in the side seal region 40D, it is sufficient that the virtual straight line K overlaps with at least one seal pattern 50D at any position in the width direction W of the side seal region 40. For this reason, the second pattern 96 and the fourth pattern 98 may also be divided. In addition, the first pattern 95, etc., may be divided into three or more.
[0094] In the above-described embodiment, an example was shown in which the seal patterns 50 formed on the left and right side seal regions 40 of the disposable diaper 1 are symmetrical. However, the seal pattern 50 formed on the left side seal region 40 and the seal pattern 50 formed on the right side seal region 40 do not have to be symmetrical. Cross-reference of related applications
[0095] This application claims priority over Japanese Patent Application No. 2025-055617, filed with the Japan Patent Office on 28 March 2025, all of which disclosures are incorporated herein by reference in their entirety.
Claims
1. A pant-type absorbent article having a side seal region formed by the continuous connection of an abdominal portion, a crotch portion, and a dorsal portion in this order, and the side portion of the abdominal portion and the side portion of the dorsal portion overlapping and joining, and having a waist opening and a pair of leg openings, wherein the side seal region has a plurality of seal patterns having a predetermined length in the width direction and being intermittently arranged along a longitudinal direction perpendicular to the width direction, when a virtual straight line extending along the longitudinal direction is set in the side seal region, the virtual straight line overlaps with at least one of the seal patterns, all the seal patterns are present in at least a part of a central region located in the middle of the width direction of the side seal region and having a predetermined length in the width direction, and the total area of the seal patterns present in the central region is greater than the total area of the seal patterns present in an inner region in the width direction inward of the central region, and the total area of the seal patterns present in an outer region in the width direction outward of the central region.
2. The absorbent pant-type article according to claim 1, characterized in that the plurality of seal patterns constitute a group of patterns that are point-symmetric with respect to a point of symmetry arbitrarily set on a center line extending in the vertical direction and set at the widthwise center position of the side seal area.
3. The absorbent pant-type article according to claim 1, characterized in that the area of the seal pattern gradually decreases from the central region toward the inner edge in the width direction or from the central region toward the outer edge in the width direction.
4. A pant-type absorbent article according to claim 1 or claim 2, characterized in that the seal pattern is divided along the width direction.