CN113226234B

CN113226234B - Composite sheet, absorbent article, and method for producing composite sheet

Info

Publication number: CN113226234B
Application number: CN201980086688.0A
Authority: CN
Inventors: 桥野夕贵; 安田翠; 石川慎一; 三好博行; 工藤悦子
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 2018-12-28
Filing date: 2019-12-25
Publication date: 2022-07-08
Anticipated expiration: 2039-12-25
Also published as: JP7285073B2; WO2020138131A1; CN113226234A; JP2020108422A

Abstract

The composite sheet having the pleats further improves the tactile sensation to the skin. The composite sheet (70) is a composite sheet for an absorbent article, and is provided with: a stretchable member (73); a first sheet (71) that is arranged so as to overlap the stretchable member and that has a first welded part (78) formed by welding fibers; and a second sheet (72) which is arranged between the first sheet and the stretchable member and has a second welded part (79) formed by welding fibers. The first welding portion and the second welding portion are respectively arranged in a plurality at intervals in the expansion and contraction direction of the expandable member. The pitch (P78) of the first welding portion in the expansion and contraction direction is different from the pitch (P79) of the second welding portion in the expansion and contraction direction.

Description

Composite sheet, absorbent article, and method for producing composite sheet

Technical Field

The present invention relates to a composite sheet used for an absorbent article or the like, an absorbent article having the composite sheet, and a method for producing the composite sheet.

Background

Patent document 1 discloses a composite sheet constituting a waist belt of an absorbent article. The composite sheet of patent document 1 has: an inner layer sheet; an outer layer sheet laminated with the inner layer sheet; a linear stretchable member disposed between the inner layer sheet and the outer layer sheet; and a joint portion joining the inner layer sheet and the outer layer sheet. The stretchable member extends in the width direction, and is arranged in a plurality of spaced-apart positions in the front-rear direction. The plurality of joining portions are arranged at intervals in the width direction and the front-rear direction.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2015-192862

Disclosure of Invention

The joint portion of the composite sheet of patent document 1 joins the inner layer sheet and the outer layer sheet by thermal welding. The sheet between the adjacent joint portions is deformed so as to bulge in the thickness direction by contraction of the stretchable member, and a fold formed by the sheet is formed between the adjacent joint portions. The skin touch of the composite sheet is improved by the pleats. However, in recent years, there has been an increasing demand for absorbent articles to have a good tactile sensation to the skin. Therefore, an object of the present invention is to further improve the skin feel of a composite sheet having wrinkles.

A composite sheet according to an aspect is a composite sheet for an absorbent article, the composite sheet including: a stretchable member; a first sheet that is disposed so as to overlap the stretchable member and that has a first welded portion formed by welding fibers; and a second sheet that is disposed between the first sheet and the stretchable member, and that has a second welded part formed by fiber welding, wherein the first welded part and the second welded part are disposed in plurality at intervals in a stretching direction of the stretchable member, and a pitch in the stretching direction of the first welded part is different from a pitch in the stretching direction of the second welded part.

An absorbent article according to one aspect has: a front-rear direction and a width direction orthogonal to the front-rear direction; a front waistline region; a rear waist region; a crotch region disposed between the front waistline region and the rear waistline region; an absorbent main body disposed across the crotch region, the front waistline region, and the rear waistline region; a front waist belt overlapping the absorbent main body in a thickness direction in the front waistline region; a rear waist band overlapping the absorbent main body in the thickness direction in the rear waist region; and a composite sheet disposed on a skin surface side surface of the front waist belt and a skin surface side surface of the rear waist belt, wherein the composite sheet comprises: the stretchable member being stretchable at least in the width direction; a first sheet that is disposed on the skin surface side of the stretchable member and has a first welded part formed by welding fibers; and a second sheet that is disposed between the first sheet and the stretchable member, and that has a second welded portion formed by fiber welding, wherein the first welded portion and the second welded portion are disposed in plurality at intervals in the width direction, and wherein a pitch in the width direction of the first welded portion is different from a pitch in the width direction of the second welded portion.

The method for manufacturing the composite sheet according to the first aspect comprises: a first sheet welding step of forming a first welded portion on a first sheet at intervals in a conveying direction; a second sheet welding step of forming a second welded portion on the second sheet at intervals in the conveying direction; and a laminating step of, after the first sheet welding step and the second sheet welding step, disposing the second sheet between a stretchable member that stretches in the conveying direction and the first sheet, wherein the second sheet welding step forms the second welded part at a pitch in the conveying direction that is different from a pitch in the conveying direction of the first welded part.

Drawings

Fig. 1 is a front view of an absorbent article of an embodiment.

Fig. 2 is a plan view of the absorbent article of the embodiment.

Fig. 3 is a sectional view taken along the line a-a of the absorbent article shown in fig. 2.

Fig. 4 is a schematic cross-sectional view of a first composite sheet as the composite sheet.

Fig. 5 is a photograph of a cross-section of a first composite sheet.

Fig. 6 is a schematic cross-sectional view of a second composite sheet as the composite sheet.

Fig. 7 is a photograph of a cross-section of a second composite sheet.

Detailed Description

(1) Brief description of the embodiments

At least the following matters will be made clear from the description of the present specification and the drawings.

A composite sheet according to an aspect is a composite sheet for an absorbent article, the composite sheet including: a stretchable member; a first sheet that is disposed so as to overlap the stretchable member and that has a first welded portion formed by welding fibers; and a second sheet that is disposed between the first sheet and the stretchable member, and that has a second welded part formed by fiber welding, wherein the first welded part and the second welded part are disposed in plurality at intervals in a stretching direction of the stretchable member, and a pitch in the stretching direction of the first welded part is different from a pitch in the stretching direction of the second welded part. The first sheet is deformed so that the first welded portions each bulge in the thickness direction due to contraction of the stretchable member. Therefore, in the first sheet, the pleats are formed between the adjacent first welded portions. Further, the second sheet is deformed so that the second welded portions each bulge in the thickness direction due to contraction of the stretchable member. Therefore, in the second sheet, a pleat is formed between the adjacent second welded portions. Since the pitch of the first welding portion is different from the pitch of the second welding portion, the first welding portion and the second welding portion are arranged to be shifted in the contraction direction. Therefore, compared with the mode that the first welding part and the second welding part are all overlapped, the hardness of the composite sheet caused by the welding part can be reduced, and the skin touch feeling can be improved.

According to a preferable mode, the pitch of the first weld may be longer than the pitch of the second weld. According to this aspect, the pitch of the second welded parts is short, and the area between the second welded parts is increased. The region between the second welded parts is a portion where the sheet is stretched and thinned and has low rigidity. On the other hand, the pitch of the first welded parts is long, and the area between the first welded parts in the first sheet is small. The first sheet has fewer regions with lower rigidity than the second sheet, and the rigidity as a whole is improved. The second sheet having low rigidity as a whole is arranged in the vicinity of the stretchable member, and fine wrinkles are easily formed in the second sheet. Further, since the first sheet is spaced apart from the stretchable member than the second sheet and the pitch of the first welded portion is relatively long, the first sheet is less likely to follow fine gathers of the second sheet, and relatively large gathers are formed in the first sheet so as to bulge in the thickness direction from the second sheet. The space is formed between the first sheet and the second sheet, so that the cushioning property of the composite sheet is improved, and the skin touch feeling can be improved.

According to another aspect, the pitch of the first weld may be shorter than the pitch of the second weld. According to this aspect, the second sheet is sandwiched between the first sheet and the stretchable member, and therefore, it is easy to follow the small gathers of the first sheet. Therefore, in the second sheet, not only large pleats by the second welded portion but also pleats that follow the small pleats by the first welded portion are easily formed. As a result, the pleats of the composite sheet are easily made uniform, local contact of the pleats with the skin can be suppressed, and the skin feel can be improved. Further, since the pitch of the first welded parts is short, the area between the first welded parts increases. The region between the first welded parts is a portion where the sheet is stretched and thinned and has low rigidity. On the other hand, the pitch of the second welded parts is long, and the area between the second welded parts is small. The first sheet has a lower rigidity in a larger area than the second sheet, and the rigidity as a whole is lowered. The first sheet having a relatively low rigidity tends to follow the second sheet, and the pleats of the composite sheet tend to become uniform.

An absorbent article according to one aspect has: a front-rear direction and a width direction orthogonal to the front-rear direction; a front waistline region; a rear waist region; a crotch region disposed between the front waistline region and the rear waistline region; an absorbent body disposed across the crotch region, the front waistline region, and the rear waistline region; a front waist belt overlapping the absorbent main body in a thickness direction in the front waist region; a rear waist band overlapping the absorbent main body in the thickness direction in the rear waist region; and a composite sheet disposed on a skin surface side surface of the front waist belt and a skin surface side surface of the rear waist belt, wherein the composite sheet comprises: the stretchable member being stretchable at least in the width direction; a first sheet that is disposed on the skin surface side of the stretchable member and has a first welded part formed by welding fibers; and a second sheet that is disposed between the first sheet and the stretchable member, and that has a second welded portion formed by fiber welding, wherein the first welded portion and the second welded portion are disposed in plurality at intervals in the width direction, and wherein a pitch in the width direction of the first welded portion is different from a pitch in the width direction of the second welded portion. According to this aspect, the skin-contact feeling with respect to the waist can be improved by forming the gathers on the skin-contact surface of the waist band. Further, since the stretchable member is stretchable in the width direction and the first welded part and the second welded part are arranged in plurality at intervals in the width direction, the composite sheet is formed with pleats extending in the front-rear direction. The gathers of the waist belt can be used to suppress the waist belt from wrinkling in the front-rear direction. The local increase in contact with the skin due to wrinkles can be suppressed, and the skin feel can be improved. Further, since at least 2 layers of the first sheet and the second sheet are disposed on the skin surface side of the stretchable member, contact of the stretchable member with the skin can be suppressed, and generation of marks of the stretchable member and marks of wrinkles on the skin can be suppressed.

Preferably, the first weld of the composite sheet disposed in the front waist belt and the second weld of the composite sheet disposed in the rear waist belt are spaced apart from each other by a distance longer than the distance between the first welds, and the first weld of the composite sheet disposed in the front waist belt and the second weld of the composite sheet disposed in the rear waist belt are spaced apart from each other by a distance shorter than the distance between the second welds. According to this aspect, the pleats of the front waist band can be made different from the pleats of the rear waist band, and the waist band can be appropriately brought into contact with the abdomen and the back, respectively, thereby improving the skin touch.

According to a preferred aspect, the composite sheet may include a first composite sheet in which the pitch of the first weld is longer than the pitch of the second weld, and the first composite sheet may be disposed in the front waist belt. In general, the abdomen is soft in skin compared with the back, and marks due to folds are easily generated. However, since the first composite sheet has high cushioning properties, contact with the skin can be alleviated, and the occurrence of marks due to wrinkles can be suppressed.

According to a preferred aspect, the stretchable member of the first composite sheet may be sheet-shaped. According to this aspect, the first sheet and the second sheet can be contracted in plane by the sheet-like stretchable member. Therefore, the pleats by the second welded portion and the pleats by the first welded portion are easily formed, the first sheet is easily lifted relative to the second sheet, and the cushioning property is easily improved.

According to a preferred aspect, the composite sheet may have a second composite sheet in which the pitch of the first weld is shorter than the pitch of the second weld, and the second composite sheet may be disposed in the rear waist belt. The back is easily pressed by body pressure in a lying posture or the like. Since the second composite sheet is likely to have uniform pleats, it is possible to disperse force by the uniform pleats when subjected to body pressure, and it is possible to suppress local contact of the pleats with the skin, and to improve the skin feel.

According to a preferred aspect, the stretchable member of the second composite sheet may be linear, and a plurality of the stretchable members may be arranged at intervals in the width direction. According to this aspect, the first sheet and the second sheet can be contracted at a point by the linear stretchable member. By locally shrinking the first and second sheets together, the pleats of the composite sheet tend to become more uniform.

The method for manufacturing the composite sheet according to the first aspect comprises: a first sheet welding step of forming a first welded portion on a first sheet at intervals in a conveying direction; a second sheet welding step of forming a second welded portion on the second sheet at intervals in the conveying direction; and a laminating step of, after the first sheet welding step and the second sheet welding step, disposing the second sheet between a stretchable member that stretches in the conveying direction and the first sheet, wherein the second sheet welding step forms the second welded part at a pitch in the conveying direction that is different from a pitch in the conveying direction of the first welded part. According to this aspect, the first sheet, the second sheet, and the stretchable member are laminated after the first welded portion of the first sheet and the second welded portion of the second sheet are formed, respectively, and therefore, the pitch of the first welded portion can be made different from the pitch of the second welded portion. Since the pitch of the first welding portion is different from the pitch of the second welding portion, the first welding portion and the second welding portion are arranged to be shifted in the contraction direction. Therefore, a composite sheet having improved tactile sensation to the skin can be obtained as compared with the case where the first welding portion and the second welding portion are all overlapped.

(2) General structure of absorbent article

Hereinafter, an absorbent article according to an embodiment will be described with reference to the drawings. In the following description of the drawings, the same or similar reference numerals are given to the same or similar parts. However, the drawings are schematic, and it should be noted that the scale of each dimension and the like are different from those in reality. Therefore, specific dimensions and the like should be determined with reference to the following description. In addition, the drawings may include portions having different dimensional relationships and ratios from each other. The absorbent article may be of a belt type or a pants type. The absorbent article may be a disposable diaper or a pants-type sanitary napkin. The absorbent article of the embodiment is a pants-type disposable diaper. Fig. 1 is a schematic front view of an absorbent article 10 of the present embodiment. Fig. 2 is a schematic plan view of the disposable diaper 10 of the present embodiment. Fig. 3 is a sectional view taken along the line a-a shown in fig. 2. Fig. 2 and 3 show an extended state in which the absorbent article 10 is extended in a state in which side joint sections 60 described later are unfolded and the gathers are not formed. In the cross-sectional view shown in fig. 3, the members are shown separately in the thickness direction T for the convenience of explanation, but in an actual product, they are in contact with each other in the thickness direction T.

The absorbent article 10 has a front-back direction L and a width direction W that are orthogonal to each other. The front-back direction L is defined by a direction extending to the front side and the back side of the body. In other words, the front-rear direction L is a direction extending front-rear in the unfolded absorbent article 10. The absorbent article 10 has a thickness direction orthogonal to both the front-back direction L and the width direction W. The absorbent article 10 has a front waistline region S1, a rear waistline region S2, and a crotch region S3. The front waistline region S1 is a region that faces the front waistline (abdomen) of the wearer. The back waistline region S2 is a region that faces the back waistline (back) of the wearer. The crotch region S3 is a region located in the crotch of the wearer and disposed between the front waistline region S1 and the rear waistline region S2. The crotch region S3 is a region in which the leg hole openings 66 (see fig. 1) described later are formed. The boundary on the crotch region side of the front waistline region S1 is the front end edge of the leg hole openings 66, and the boundary on the crotch region side of the rear waistline region S2 is the rear end edge of the leg hole openings 66.

The absorbent article 10 may have an absorbent main body 40 and a waist belt 15. The waist belt 15 overlaps the absorbent main body 40 in the thickness direction. The waist belt 15 may have a front waist belt 20 and a rear waist belt 30. The front waist belt 20 is disposed in the front waistline region S1 in a region overlapping with the absorbent main body 40 and in a region not overlapping with the absorbent main body 40. The rear waist belt 30 is separated from the front waist belt 20 in the front-rear direction L. The rear waist belt 30 is disposed in the rear waistline region S2 in a region overlapping the absorbent main body 40 and in a region not overlapping the absorbent main body 40. In another embodiment, the waist belt 15 may be configured to span from the front waistline region S1 to the rear waistline region S2 by integrating the front waist belt 20 and the rear waist belt 30.

As shown in fig. 3, the front waist belt 20 may have: a front cover sheet 27 disposed on the skin surface side T1 of the absorbent main body 40; a front first outer sheet 25 disposed on the non-skin surface side T2 of the absorbent main body 40; a front second outer sheet 26 positioned on the non-skin surface side T2 of the front first outer sheet 25; and an outer stretchable sheet 28 disposed between the front first outer sheet 25 and the front second outer sheet 26. In the region not overlapping the absorbent main body 40, the front cover sheet 27, the front first outer sheet 25, the outer stretchable sheet 28, and the front second outer sheet 26 are laminated in this order from the skin surface side T1 toward the non-skin surface side T2, and are joined to each other. The front cover sheet 27, the front first exterior sheet 25, and the front second exterior sheet 26 may be formed of different sheets or may be formed of the same sheet that is folded back. The front cover sheet 27, the front first exterior sheet 25, and the exterior stretchable sheet 28 may constitute a first composite sheet 70A (composite sheet 70) of the present invention. The front cover sheet 27 may constitute the first sheet 71 in the first composite sheet 70A of the present invention, the front first outer sheet 25 may constitute the second sheet 72 in the first composite sheet 70A of the present invention, and the outer stretchable sheet 28 may constitute the stretchable member 73 in the first composite sheet 70A of the present invention. The composite sheet 70 will be described in detail later.

As shown in fig. 3, the rear waist belt 30 may have: a back cover sheet 37 disposed on the skin surface side T1 of the absorbent body 40; a rear first outer sheet 35 disposed on the non-skin surface side T2 of the absorbent main body 40; a rear second outer sheet 36 positioned on the non-skin surface side T2 of the rear first outer sheet 35; and a rear rubber thread 38 disposed between the rear first exterior sheet 35 and the rear second exterior sheet 36. In the region not overlapping the absorbent main body 40, the rear cover sheet 37, the rear first exterior sheet 35, the rear rubber thread 38, and the rear second exterior sheet 36 may be laminated in order from the skin-surface side T1 toward the non-skin-surface side T2 and joined to each other. Further, the rear third outer sheet 39 may be disposed on the skin surface side of the rear first outer sheet 35. In the region where the rear third outer sheet 39 is disposed, the rear cover sheet 37, the rear third outer sheet 39, the rear first outer sheet 35, the rear rubber thread 38, and the rear second outer sheet 36 may be laminated in order from the skin surface side T1 toward the non-skin surface side T2, and joined to each other. The rear cover sheet 37, the rear first exterior sheet 35, the rear second exterior sheet 36, and the rear third exterior sheet 39 may be formed of different sheets or may be formed of the same sheet that is folded back. In the present embodiment, the second exterior sheet 36 and the third exterior sheet 39 are formed of the same sheet folded back at the waist opening 62.

The rear first exterior sheet 35, the rear third exterior sheet 39, and the rear side rubber thread 38 may constitute a second composite sheet 70B (composite sheet 70) of the present invention. The rear first outer sheet 35 may constitute the second sheet 72 in the second composite sheet 70B of the present invention, the rear third outer sheet 39 may constitute the first sheet 71 in the second composite sheet 70B of the present invention, and the rear rubber thread 38 may constitute the stretchable member 73 in the second composite sheet 70B of the present invention.

As shown in fig. 1, a side joining unit 60 may be provided in which the outer side portion of the front waistline region S1 and the outer side portion of the rear waistline region S2 are joined. The side joint portions 60 are defined by portions that lock the outer portions of the front waistline region S1 and the outer portions of the rear waistline region S2 in the width direction W to each other. The outer portion in the present invention means a portion that occupies a certain range in the width direction W including the outer edge in the width direction W, and the outer edge means the outer edge in the width direction W. The inner side portion in the present invention means a portion that occupies a certain range in the width direction W including an inner edge in the width direction W, and the inner edge means an inner edge in the width direction W. The front end portion and the rear end portion in the present invention are portions that occupy a certain range in the front-rear direction L including edges in the front-rear direction L, and the front end edge and the rear end edge are edges in the front-rear direction L. The outer end portion includes a front end portion and a rear end portion, and the outer end edge includes a front end edge and a rear end edge.

As shown in fig. 1, in the absorbent article 10, a waist opening 62 through which the waist of the wearer passes and a pair of leg openings 66 into which the legs of the wearer are inserted are formed in a state in which the side joint sections 60 are formed. The waist opening 62 may be defined by the front end edge S1F of the front waist region S1 and the rear end edge S2R of the rear waist region S2. Here, fig. 2 shows a state in which the engagement at the side joint portions 60 is released and the absorbent article 10 is unfolded. The side joint portions 60 may extend in the front-rear direction L in the front waist belt 20 and the rear waist belt 30, respectively. In the pants-type absorbent article, the boundary between the front waistline region S1 and the crotch region S3 may be defined by the rear end edge of the side joint portion 60 provided in the front waist band 20. Similarly, the boundary between the rear waistline region S2 and the crotch region S3 may be defined by the front end edge of the side joining portion 60 provided in the rear waist belt 30.

As shown in fig. 3, a stretchable member stretchable in the width direction W may be disposed in the front waistline region S1. The stretchable member may be constituted by at least one of the front rubber thread 22 stretchable in the width direction W and the outer stretchable sheet 28 stretchable in the width direction W. Alternatively, the stretchable member may be constituted by the front waist belt 20 itself made of, for example, a stretchable sheet. The rear waist region S2 may be provided with a stretchable member stretchable in the width direction W. The stretchable member may be formed of at least one of the rear rubber thread 38 stretchable in the width direction W and an outer stretchable sheet stretchable in the width direction W. Alternatively, the stretchable member may be constituted by the rear waist belt 30 itself, which is constituted by a stretchable sheet, for example.

The absorbent main body 40 is disposed across the front waist belt 20 and the rear waist belt 30. That is, the absorbent main body 40 extends over the front waistline region S1, the rear waistline region S2, and the crotch region S3. The absorbent main body 40 may be configured separately from the front waist belt 20 and the rear waist belt 30. In this case, the absorbent main body 40 may be joined to the front waist belt 20 and the rear waist belt 30 in the front waistline region S1 and the rear waistline region S2, respectively. The absorbent main body 40 includes at least an absorbent core 50. The absorbent core 50 may comprise, for example, comminuted pulp or a Super Absorbent Polymer (SAP), or mixtures thereof. The absorbent core 50 is disposed at least in the crotch region S3. Preferably, the absorbent core 50 may extend in the front-back direction L from the front waistline region S1 to the back waistline region S2. The absorbent core 50 may be covered by a core cladding. Also, as shown in fig. 3, the absorbent main body 40 may have: a skin surface sheet 42A disposed on the skin surface side of the absorbent core; a liquid-impermeable sheet 41 disposed on the non-skin surface side of the absorbent core 50; and a main body sheet 42B disposed on the non-skin surface side T2 with respect to the liquid-impermeable sheet 41.

(3) Structure of composite sheet

Next, the structure of the composite sheet 70 will be described in detail with reference to fig. 4 to 7. The composite sheet is a sheet for an absorbent article. Fig. 4 is a schematic cross-sectional view of a first composite sheet 70A as the composite sheet 70, fig. 4(a) being an extended state, and fig. 4(b) showing a contracted state after contraction of the stretchable member. Fig. 5 is a cross-sectional photograph of the first composite sheet 70A. Fig. 6 is a schematic cross-sectional view of a second composite sheet 70B as the composite sheet 70, fig. 6(a) being an extended state, and fig. 6(B) showing a contracted state after contraction of the stretchable member. For convenience of explanation, in fig. 6, the rear first exterior sheet 35 composed of the laminated body 76 is illustrated in one layer. Fig. 4 and 6 are schematic views showing the composite sheet, and the shape of the entire composite sheet such as the shape of the welded portion is not limited to the drawings. Fig. 7 is a cross-sectional photograph of the second composite sheet 70B. In fig. 4 and 5, only the first composite sheet 70A is shown, and the front second outer sheet 26 and the front rubber string 22 among the members constituting the front waist belt 20 are omitted. In fig. 6 and 7, only the second composite sheet 70B is shown, and the rear second outer sheet 36 and the rear cover sheet 37 among the members constituting the rear waist belt 30 are omitted. In the following description, the configuration in which the first composite sheet 70A is disposed in the front waist belt 20 and the second composite sheet 70B is disposed in the rear waist belt 30 will be described, but in a modified example, the second composite sheet 70B may be disposed in the front waist belt 20 or the first composite sheet 70A may be disposed in the rear waist belt 30.

The composite sheet 70 includes: a stretchable member 73; a first sheet 71 arranged to overlap the stretchable member 73 and having a first welded part 78 formed by thermally welding fibers; and a second sheet 72 disposed between the first sheet 71 and the stretchable member 73 and having a second welded part 79 formed by fiber heat welding. The first sheet 71 and the second sheet 72 may be made of, for example, nonwoven fabric as long as they have fibers. The first sheet 71 and the second sheet 72 may be one or more layers, and may be a laminate 76 as in the first exterior sheet 35 described later.

The first welded portion 78 welds fibers of the sheet constituting the first sheet 71. The first welded portion 78 is a welded portion formed in the first sheet 71, and is not formed in the second sheet 72. The second welded portion 79 welds the fibers of the sheets constituting the second sheet 72. The second welded portion 79 is a welded portion formed in the second sheet 72, and is not formed in the first sheet 71. That is, first weld 78 and second weld 79 are provided separately. The first welded part 78 and the second welded part 79 may be formed by any one of heat welding, ultrasonic welding, and embossing. The first welding portion 78 and the second welding portion 79 are disposed at intervals in the expansion and contraction direction D1 of the expandable member 73. The pitch P78 in the expansion and contraction direction of the first welding portion 78 is different from the pitch P79 in the expansion and contraction direction of the second welding portion 79.

As shown in fig. 4(b) and 6(b), the composite sheet 70 is contracted in the expansion and contraction direction D1 by contraction of the stretchable member 73, thereby contracting the first sheet 71 and the second sheet 72. At this time, the first sheet 71 is deformed so that the first welded portions 78 each bulge in the thickness direction T due to contraction of the stretchable member 73. In the first sheet 71, pleats are formed between the adjacent first welded portions 78. Further, the second sheet 72 is deformed so that the second welded portions 79 each bulge in the thickness direction T by contraction of the stretchable member 73. In the second sheet 72, a pleat is formed between the adjacent second welded parts 79. Since the pitch P78 of the first weld 78 is different from the pitch P79 of the second weld 79, the first weld 78 and the second weld 79 are arranged offset in the contraction direction. Therefore, compared to the mode in which the first welded portion 78 and the second welded portion 79 are all overlapped, the hardness of the composite sheet 70 due to the welded portion can be reduced, and the skin feel can be improved. Further, since at least 2 layers of the first sheet 71 and the second sheet 72 are disposed on the skin surface side T1 with respect to the stretchable member 73, contact of the stretchable member 73 with the skin can be suppressed, and generation of marks of the stretchable member 73 and marks of wrinkles on the skin can be suppressed. Note that, the pitch P78 in the expansion and contraction direction of the first welding portion 78 and the pitch P79 in the expansion and contraction direction of the second welding portion 79 may be different from each other in all or part of the composite sheet. That is, the pitch of the first welded part 78 and the pitch of the second welded part are all included in the concept except that the pitches of the composite sheet 70 are identical as a whole.

As shown in fig. 4 and 5, the pitch P78 of the first welding portion 78 may be longer than the pitch P79 of the second welding portion 79. Pitch P79 of second welded parts 79 is short, and the area between second welded parts 79 is increased. The region between the second welded parts 79 is a portion where the sheet is stretched to be thin and low in rigidity. On the other hand, pitch P78 of first weld 78 is long, and the area between first weld 78 is small. The first sheet 71 has fewer regions with lower rigidity than the second sheet 72, and the rigidity as a whole is improved. The second sheet 72 having low rigidity as a whole is disposed in the vicinity of the stretchable member 73, and fine wrinkles are easily formed in the second sheet 72. Further, since the first sheet 71 is farther from the stretchable member 73 than the second sheet 72 and the pitch of the first welded parts 78 is relatively long, it is difficult to form relatively large wrinkles in the first sheet 71 so as to bulge in the thickness direction from the second sheet 72 along the fine wrinkles of the second sheet 72. The space S is formed between the first sheet 71 and the second sheet 72, so that the composite sheet 70 has improved cushioning properties and improved tactile sensation to the skin. In the present embodiment, in the first composite sheet 70A disposed in the front waist belt 20, the pitch P78 of the first weld 78 is longer than the pitch P79 of the second weld 79.

As shown in fig. 6 and 7, pitch P78 of first weld 78 may be shorter than pitch P79 of second weld 79. The second sheet 72 is sandwiched between the first sheet 71 and the stretchable member 73, and therefore easily follows the small pleats of the first sheet 71. In the second sheet 72, not only large pleats by the second welded portion 79 but also pleats that follow small pleats by the first welded portion 78 are easily formed. As a result, the pleats of the composite sheet 70 are easily made uniform, local contact of the pleats with the skin can be suppressed, and the skin feel can be improved. Further, since pitch P78 of first welded parts 78 is short, the area between first welded parts 78 increases. The region between first welded parts 78 becomes a portion with low rigidity. On the other hand, the pitch of the second welded parts is long, and the area between the second welded parts is small. The first sheet has a lower rigidity in a larger area than the second sheet, and the rigidity as a whole is lowered. The first sheet 71 having relatively low rigidity tends to follow the second sheet 72, and the pleats of the composite sheet tend to be uniform. In the present embodiment, in the second composite sheet 70B disposed in the rear waist belt 30, the pitch P78 of the first weld 78 is shorter than the pitch P79 of the second weld 79.

(4) Structure of absorbent article having composite sheet

Next, the structure of the absorbent article 10 having the composite sheet 70 will be described. The composite sheet 70 has cushioning properties, and is particularly preferably disposed in an area intended to improve the tactile sensation of the skin. The composite sheet 70 is disposed on the skin surface side surface of the front waist belt 20 and the skin surface side surface of the rear waist belt 30. A front cover sheet 27 is disposed on the skin surface side surface of the front waist belt 20, and a rear cover sheet 37 is disposed on the skin surface side surface of the rear waist belt 30. The skin-contact surface of the waist band is provided with pleats to improve the skin-contact feeling with respect to the waist. As a modification, the composite sheet 70 may be disposed on leg flaps disposed along the leg circumferences of the wearer. According to the modification, the feeling of the wearer's leg circumference can be improved.

The stretchable direction D1 of the stretchable member in the composite sheet 70 is along the width direction W, and a plurality of first welded parts 78 and second welded parts 79 are arranged at intervals in the width direction W. Therefore, the composite sheet 70 is formed with pleats extending in the front-rear direction L. The gathers of the waist belt 15 can be used to suppress the gathers of the waist belt 15 in the front-rear direction L. The local increase in contact with the skin due to wrinkles can be suppressed, and the skin feel can be improved.

The pitch P78 of the first weld 78 of one of the composite sheet 70 disposed in the front waist belt 20 and the composite sheet 70 disposed in the rear waist belt 30 may be longer than the pitch of the second weld 79, and the pitch P78 of the first weld 78 of the other of the composite sheet disposed in the front waist belt 20 and the composite sheet disposed in the rear waist belt 30 may be shorter than the pitch P79 of the second weld 79. In the present embodiment, the pitch P78 of the first weld 78 of the composite sheet disposed in the front waist belt 20 is longer than the pitch of the second weld 79, and the pitch P78 of the first weld 78 of the composite sheet disposed in the rear waist belt 30 is shorter than the pitch P79 of the second weld 79. With this configuration, the pleats of the front waist band 20 can be made different from the pleats of the rear waist band 30, and the waist band 15 can be appropriately brought into contact with the abdomen and the back, respectively, thereby improving the tactile sensation of the skin.

The first composite sheet 70A is configured such that the pitch P78 of the first weld 78 is longer than the pitch P79 of the second weld 79. The first composite sheet 70A may be disposed at the front waist belt 20. In general, the abdomen is soft in skin compared with the back, and marks due to folds are easily generated. However, since the first composite sheet 70A has high cushioning properties, contact with the skin can be alleviated, and the occurrence of marks due to wrinkles can be suppressed.

The stretchable member 73 of the first composite sheet 70A may be sheet-shaped. The stretchable member 73 of the first composite sheet 70A of the present embodiment is an outer stretchable sheet 28. The first sheet 71 and the second sheet 72 can be contracted in plane by the sheet-like stretchable member 73. Therefore, the pleats by the second welded part 79 and the pleats by the first welded part 78 are easily formed, the first sheet 71 is easily lifted relative to the second sheet 72, and the cushioning property is easily improved.

The second composite sheet 70B is configured such that the pitch P78 of the first weld zone 78 is shorter than the pitch P79 of the second weld zone 79. The second composite sheet 70B may be disposed at the rear waist belt 30. The back is easily subjected to body pressure in a lying posture or the like. Since the second composite sheet is likely to have uniform pleats, it is possible to disperse force by the uniform pleats when subjected to body pressure, and it is possible to suppress local contact of the pleats with the skin, and to improve the skin feel.

The stretchable members 73 of the second composite sheet 70B may be linear and arranged in plural at intervals in the width direction W. The stretchable member 73 of the second composite sheet 70B of the present embodiment is the rear rubber thread 38, and a plurality of the stretchable members are arranged at intervals in the width direction W. The first sheet and the second sheet can be contracted at a point by the linear stretchable member. By locally shrinking the first and second sheets together, the pleats of the composite sheet tend to become more uniform.

(5) Method for manufacturing composite sheet

Next, a method for manufacturing the composite sheet configured as described above will be described. The method for manufacturing the composite sheet includes a first sheet welding step, a second sheet welding step, and a laminating step. The first sheet welding step forms first welded portions on the first sheet 71 at intervals in the conveying direction. In the first sheet welding step, the first welded portion may be formed in a first continuous sheet body in which the first sheet 71 is continuous in the conveying direction. The second sheet welding step forms second welded portions on the second sheet at intervals in the conveying direction. In this case, the second sheet welding step forms the second welded parts at a pitch in the conveying direction different from a pitch in the conveying direction of the first welded parts. In the second sheet welding step, the second welded portion may be formed in a second sheet continuous body in which the second sheet 72 is continuous in the conveying direction. The laminating step is performed after the first sheet welding step and the second sheet welding step. In the laminating step, the second sheet is disposed between the stretchable member 73 stretched in the conveying direction and the first sheet. In the laminating step, the first sheet 71, the second sheet 72, and the stretchable member 73 are bonded to each other by an adhesive member such as an adhesive.

According to the method of manufacturing the composite sheet, since the first sheet, the second sheet, and the stretchable member are laminated after the first welded portion of the first sheet and the second welded portion of the second sheet are formed, respectively, the pitch of the first welded portion 78 can be made different from the pitch P79 of the second welded portion 79. Since the pitch of the first welding portion is different from the pitch of the second welding portion, the first welding portion and the second welding portion are arranged to be shifted in the contraction direction. Therefore, compared with the mode that the first welding part and the second welding part are all overlapped, the composite sheet with improved skin touch feeling can be obtained.

While the present invention has been described in detail with reference to the above embodiments, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described in the present specification. The present invention may be embodied with modifications and variations without departing from the spirit or scope of the present invention defined by the claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

In addition, the entire contents of patent application No. 2018-248611, filed in japan on 12/28/2018, are incorporated by reference into the present specification.

Industrial applicability

The composite sheet having the gathers can further improve the tactile sensation to the skin.

Description of the reference numerals

10: absorbent article, 20: front waist band, 25: front first exterior sheet (second sheet), 26: front second exterior sheet, 27: front cover sheet (first sheet), 28: outer stretchable sheet (stretchable member), 30: rear waist band, 35: rear first exterior sheet (second sheet), 36: rear second exterior sheet, 37: rear cover sheet, 38: rear rubber wire (stretchable member), 39: rear third exterior sheet (first sheet), 40: absorbent body, 41: liquid-impermeable sheet, 42A: skin sheet, 42B: body sheet, 50: absorbent core, 60: side joint, 70: composite sheet, 71: first sheet, 72: second sheet, 73: stretchable member, D1: expansion and contraction direction, S1: front waistline region, S2: rear waist region, S3: crotch region, L: front-rear direction, T: thickness direction, T1: skin surface side, T2: non-skin surface side, W: the width direction.

Claims

1. A composite sheet used in an absorbent article and disposed on a surface of a waist belt on a skin surface side, the absorbent article comprising: a front waistline region; a rear waist region; a crotch region disposed between the front waistline region and the rear waistline region; an absorbent main body disposed across the crotch region, the front waistline region, and the rear waistline region; and the waist belt overlapping the absorbent main body in a thickness direction in the front waistline region or the back waistline region,

wherein the composite sheet comprises:

a stretchable member;

a first sheet that is disposed on a skin surface side of the stretchable member and has a first welded part formed by welding fibers; and

a second sheet disposed between the first sheet and the stretchable member and having a second welded portion formed by welding fibers,

a plurality of first welding parts and a plurality of second welding parts are arranged at intervals in the expansion and contraction direction of the stretchable member,

the pitch in the expansion/contraction direction of the first welding part is different from the pitch in the expansion/contraction direction of the second welding part.

2. The composite sheet of claim 1,

the pitch of the first weld is longer than the pitch of the second weld.

3. The composite sheet of claim 1,

the pitch of the first welding part is shorter than the pitch of the second welding part.

4. An absorbent article having:

a front-rear direction and a width direction orthogonal to the front-rear direction;

a front waistline region;

a rear waist region;

a crotch region disposed between the front waistline region and the rear waistline region;

an absorbent main body disposed across the crotch region, the front waistline region, and the rear waistline region;

a front waist belt overlapping the absorbent main body in a thickness direction in the front waist region;

a rear waist band overlapping the absorbent main body in the thickness direction in the rear waist region; and

a composite sheet disposed on a surface on the skin surface side of the front waist belt and a surface on the skin surface side of the rear waist belt,

wherein the content of the first and second substances,

the composite sheet is provided with:

a stretchable member that stretches and contracts at least in the width direction;

a first sheet that is disposed on the skin surface side of the stretchable member and has a first welded part formed by welding fibers; and

a plurality of first welding parts and a plurality of second welding parts are arranged at intervals in the width direction,

the pitch in the width direction of the first welded part is different from the pitch in the width direction of the second welded part.

5. The absorbent article of claim 4,

the first weld portion of the composite sheet disposed on one of the front waist belt and the rear waist belt has a longer pitch than the second weld portion,

the first weld portion of the other of the composite sheet disposed in the front waist belt and the composite sheet disposed in the rear waist belt has a pitch shorter than a pitch of the second weld portion.

6. The absorbent article of claim 4 or 5,

the composite sheet has a first composite sheet in which the pitch of the first weld is longer than the pitch of the second weld,

the first composite sheet is disposed at the front waist belt.

7. The absorbent article of claim 6,

the stretchable member of the first composite sheet is sheet-shaped.

8. The absorbent article of claim 4 or 5,

the composite sheet has a second composite sheet in which the pitch of the first weld is shorter than the pitch of the second weld,

the second composite sheet is arranged on the rear waist belt.

9. The absorbent article of claim 8,

the second composite sheet has a plurality of linear stretchable members arranged at intervals in the width direction.

10. A method for manufacturing a composite sheet used for an absorbent article and disposed on a surface of a waist belt on a skin surface side, the absorbent article comprising: a front waistline region; a rear waist region; a crotch region disposed between the front waistline region and the rear waistline region; an absorbent main body disposed across the crotch region, the front waistline region, and the rear waistline region; and the waist belt overlapping the absorbent main body in a thickness direction in the front waistline region or the back waistline region,

wherein the manufacturing method of the composite sheet comprises the following steps:

a first sheet welding step of forming a first welded portion on a first sheet at intervals in a conveying direction;

a second sheet welding step of forming a second welded portion on the second sheet at intervals in the conveying direction; and

a laminating step of laminating the first sheet, the second sheet, and the stretchable member by disposing the second sheet between a stretchable member stretched in the conveyance direction and the first sheet disposed on a skin surface side of the stretchable member after the first sheet welding step and the second sheet welding step,

the second sheet welding step forms the second welded parts at a pitch in the conveying direction different from a pitch in the conveying direction of the first welded parts.