JP7448436B2 - absorbent articles - Google Patents

Description

The present invention relates to absorbent articles.

Absorbent articles generally include a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between them, and absorb body fluids such as urine that have passed through the top sheet. It is designed to be absorbed and retained by the body. There are various types of absorbent articles depending on the purpose, such as tape-type disposable diapers, pants-type disposable diapers, urine absorbing pads, and light incontinence pads, regardless of whether they are for adults or infants.

Conventionally, it has been common to use fluff pulp and a super absorbent polymer (hereinafter also referred to as "SAP") in combination as an absorbent material. Fluff pulp absorbent materials containing fluff pulp and SAP have good absorption performance, texture, and feel when worn, but in recent years, it has become easier to wear absorbent articles because it is not noticeable and does not feel strange when worn. There is a demand for thin absorbent articles that do not give a feeling of feeling. Further, for care recipients, thin absorbent articles with good fit are comfortable and easy to change the direction of the body, which is desirable.

In making absorbent articles thinner, a major challenge is to make the absorbent body, which makes up the majority of the absorbent article, thinner. As such a thin absorbent body, for example, a superabsorbent sheet (hereinafter also referred to as "SAP sheet") comprising two nonwoven fabrics and SAP particles fixedly supported between them by a hot melt adhesive; Absorbent articles using SAP sheets as absorbers have been proposed.

Patent Document 1 discloses a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-permeable back sheet disposed between them, with the aim of preventing an increase in the thickness of the absorbent core and improving the amount of body fluid absorbed. The absorbent body includes a lower absorbent body located on the non-skin side of the wearer, and a central part in the longitudinal and width directions of the skin side of the lower absorbent body located on the skin side of the wearer. The upper absorbent layer is an SAP sheet including a first nonwoven fabric, a second nonwoven fabric, and SAP particles held between them, and the lower absorbent layer is an It is a fluff pulp absorbent core, and is provided at both ends of the upper absorbent core in the width direction, and has two joints where the upper absorbent core and the lower absorbent core are joined, and a joint between these joints in the longitudinal direction of the upper absorbent core. An absorbent article is disclosed that includes a non-joined portion that extends from one end to the other end and does not join an upper absorbent layer and a lower absorbent layer.

JP 2018-164633 Publication

Patent Document 1 attempts to improve the amount of body fluid absorbed by combining a thin SAP sheet as an upper layer absorber and a fluff pulp absorber as a lower layer absorber. However, since fluff pulp absorbers and SAP sheets are completely different in structure, strength, density, and properties after absorbing body fluids, the absorbent body as a whole deforms while absorbing body fluids multiple times, resulting in leakage of body fluids. , problems such as a decrease in absorption performance such as absorption speed and amount, and a decrease in wearing comfort and fit are likely to occur. In Patent Document 1, the above-described bonded portion and non-bonded portion are provided between the upper layer absorbent core and the lower layer absorbent core, but such a structure may encourage deformation of the absorbent core.

Furthermore, when an absorbent body is constructed by laminating a plurality of SAP sheets, the absorbent body becomes thinner than a conventional fluff pulp absorbent body, but the rigidity of the absorbent body tends to be relatively high, making it impossible to maintain good fit. When absorbent articles are expected to be worn for long periods of time, it is particularly desirable to suppress deterioration in fit due to swelling of SAP after absorption of body fluids.

An object of the present invention is to provide an absorbent article that is thin, has excellent absorption performance such as repeated absorption rate and amount of body fluid absorbed, prevents liquid return, and has good fit even after absorbing body fluid.

As a result of extensive research in order to solve the above problems, the present inventor has developed a three-layer laminate in which three layers of superabsorbent sheets are superimposed in the thickness direction, and each superabsorbent sheet is placed on the side of the wearer's skin. A pair of rigid buffer sections, each of which has a predetermined shape and dimensions and has a lower basis weight of superabsorbent polymer than the other areas, and which gradually widens toward the non-skin side, and has a predetermined shape and dimensions at a predetermined position on each superabsorbent sheet. The present invention has been completed based on the discovery that a thin absorbent article having desired properties can be obtained by using an absorbent body in which predetermined rigid buffer sections partially overlap in the thickness direction. reached. That is, the present invention relates to the following absorbent article.

(1) An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between them,
The absorber is
A first sheet, a second sheet wider than the first sheet, and a third sheet wider than the second sheet are stacked in this order from the wearer's skin side to the non-skin side. A three-layer laminate is included, and the first sheet, the second sheet, and the third sheet are all superabsorbent sheets in which a superabsorbent polymer is firmly supported between two sheets of hydrophilic nonwoven fabric. can be,
The first sheet, the second sheet, and the third sheet each face each other in the width direction, extend in an arc shape in the length direction, and have a higher area weight of the superabsorbent polymer than other areas. a pair of first stiffness buffering parts, a pair of second stiffness buffering parts, and a pair of third stiffness buffering parts, each of which has a low stiffness,
The first rigid buffer section and the second rigid buffer section have a region X that overlaps in the thickness direction, and the second rigid buffer section and the third rigid buffer section have a region Y that overlaps in the thickness direction. and the absorbent body further includes a fold-shaped buffer line extending linearly from one end in the length direction to the other end in the length direction, and the buffer line is connected to the first sheet, the second sheet, and An absorbent article characterized in that at least one of the third sheets has a central buffer line provided at the center in the width direction and/or an end buffer line provided near the ends in the width direction.
(2) The first rigid buffer section, the second rigid buffer section, and the third rigid buffer section each have a basis weight of the superabsorbent polymer of 60 g/m ² or less, a radius of curvature of 360 mm or more and 830 mm or less, and a length of 150 mm. The absorbent article according to (1) above, which has a width of 10 mm or more and 45 mm or less, and a width of 10 mm or more and 45 mm or less.
(3) The area of the region The absorbent article according to (1) or (2) above, which is 30% or more and 65% or less.
(4) The length and width of the second rigid buffer section are respectively greater than the length and width of the first rigid buffer section, and the length and width of the third rigid buffer section are respectively greater than the length and width of the second rigid buffer section. The absorbent article according to any one of (1) to (3) above, which has a length and width greater than the length and width of the absorbent article.
(5) The outer edge in the width direction of the second rigid buffer part is located on the outer side in the width direction than the outer edge in the width direction of the first rigid buffer part, and the outer edge in the width direction of the third rigid buffer part The absorbent article according to any one of (1) to (4) above, wherein the edge is located on the outer side in the width direction than the edge on the outer side in the width direction of the second rigid buffer section.
(6) The absorbent article according to any one of (1) to (5) above, wherein the hydrophilic nonwoven fabric is an air-through nonwoven fabric.

According to the present invention, an absorbent article is provided that is thin, has excellent absorption performance such as repeated absorption rate and amount of body fluid absorbed, prevents liquid return, and has good fit even after absorption of body fluid.

1 is a schematic plan view showing the configuration of an absorbent article according to a first embodiment of the present invention. 2 is a schematic cross-sectional view in the width direction taken along the line X ₁ -X ₁ shown in FIG. 1. FIG. FIG. 2 is a schematic plan view showing the structure of the absorbent core in the absorbent article shown in FIG. 1. FIG. FIG. 2 is a schematic development view of the absorbent core in the absorbent article shown in FIG. 1. FIG. FIG. 2 is a schematic plan view showing the overlap in the thickness direction of the rigid buffer portions of the superabsorbent sheets of the absorbent core in the absorbent article shown in FIG. 1. FIG. (a) to (c) are all schematic plan views. FIG. 3 is a schematic plan view showing the configuration of a center buffer line and an end buffer line provided on a first sheet, a second sheet, and a third sheet. (a) is the first sheet, (b) is the second sheet, and (c) is the third sheet. FIG. 4 is a schematic cross-sectional view in the width direction taken along the line X ₂ -X ₂ in FIG. 3 for explaining the effects of the absorber of the present embodiment. (a) is a schematic cross-sectional view. (b) is a schematic cross-sectional view showing deformation of the absorber.

In this specification, wearing an absorbent article refers to a state in which the absorbent article is worn on the body, regardless of whether before or after absorbing body fluids. In an absorbent article, the length direction (or longitudinal direction) is the direction indicated by Y in the figure that extends from the front and back of the wearer's crotch area when the absorbent article is worn on the body, and the width direction is the direction indicated by X in the figure, which is orthogonal to the length direction, and the thickness direction is the direction indicated by Z in the figure, in which each component is laminated. The skin side refers to the surface that contacts or faces the wearer's skin when the absorbent article is worn, and the non-skin side refers to the surface that contacts or faces the wearer's clothing. be. Body fluids refer to fluids discharged from the body, such as urine, blood, and water in loose stools.

<Absorbent article (first embodiment)>
The absorbent article 50 of this embodiment will be described below with reference to the drawings. 1 and 2 show an absorbent article 50 according to a first embodiment. 3 to 6 show the absorbent body 20. FIG. These drawings do not specify the shape, size, size relationship, etc. of each component in the absorbent article 50.

The absorbent article 50 of this embodiment can be used as a variety of absorbent articles regardless of whether it is for babies or adults, but typical examples include light incontinence pads, urine absorbing pads, pants-type disposable diapers, and tape-fastened disposable diapers. Can be mentioned. Various paper diapers as an outer and the absorbent article 50 as an inner may be combined. The absorbent article 50 is suitably used, for example, by a care recipient who is not bedridden but can be guided to the bathroom with assistance, a bedridden caregiver who is mainly used in a supine position, etc.; It can also be used by people who do not want to require nursing care. The length (lengthwise dimension, the same hereinafter) and width (widthwise dimension, the same hereinafter) of the absorbent article 50 are not particularly limited, but are, for example, in the range of 100 mm or more and 800 mm or less, and 50 mm or more and 500 mm or less. is within the range of By adjusting the dimensions of the absorbent article 50 within the above range, absorbent articles for various uses can be easily obtained.

As shown in FIGS. 1 and 2, the absorbent article 50 includes a liquid-permeable top sheet 10 that is located relatively on the skin side when the absorbent article 50 is worn, and a top sheet that faces the top sheet 10. a liquid-impermeable backsheet 30 that is placed on the non-skin side when the absorbent article 50 is worn; an absorbent body 20 that is placed between the topsheet 10 and the backsheet 30; A pair of three-dimensional gathers 40 are provided on the skin side surface of the top sheet 10. The absorbent body 20 is sandwiched between the top sheet 10 and the back sheet 30, and body fluids such as urine are absorbed and retained in the absorbent body 20 through the top sheet 10. Depending on the use and type of the absorbent article 50, leg gathers, waist gathers, side flaps, etc. can be provided as appropriate.

Hereinafter, each of the sheet-like constituent members will be explained in more detail in the order of the top sheet 10, the absorbent core 20, the back sheet 30, and the three-dimensional gathers 40. Note that these constituent members may have a three-dimensional structure other than sheet-like.

(Top sheet)
The top sheet 10 is a liquid-permeable sheet-like member that allows body fluids to quickly pass through toward the absorbent body 20, and is disposed opposite to the back sheet 30 with the absorbent body 20 in between. Since the top sheet 10 may come into contact with the wearer's skin, it is preferable to use a base material that is soft to the touch and does not irritate the skin. Examples of the base material include hydrophilic sheets, composite nonwoven fabrics that are laminates of the same or different types of hydrophilic sheets, open films such as open polyethylene films, and foamed films such as polyethylene foam and urethane foam. Examples of hydrophilic sheets include air-through nonwoven fabrics made using one or more of synthetic fibers made of synthetic resins such as polypropylene, polyethylene, and polyester, recycled fibers such as rayon, and natural fibers such as cotton. , thermal bond nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, etc.

From the viewpoint of improving liquid permeability, the top sheet 10 may be subjected to embossing or perforation on the surface according to a known method. In addition, from the viewpoint of reducing skin irritation, the top sheet 10 may contain one or more of a lotion, an antioxidant, an anti-inflammatory ingredient, a pH adjuster, an antibacterial agent, a moisturizer, etc. good. The basis weight of the top sheet 10 is, for example, in the range of 15 g/m ² or more and 40 g/m ^{2 or} less from the viewpoint of strength, workability, and liquid return amount. The shape of the top sheet 10 is not particularly limited, and may be any shape that covers part or all of the absorbent body 20 as required to guide body fluids to the absorbent body 20 to prevent leakage.

(Absorber)
The absorber 20 has a length of, for example, 100 mm or more and 800 mm or less, 150 mm or more and 500 mm or less, or 270 mm or more and 500 mm or less, and a width of 50 mm or more and 500 mm or less, 60 mm or more and 400 mm or less, Or it is in the range of 90 mm or more and 190 mm or less. In addition, when the shape of the absorbent body 20 in plan view is an hourglass shape, the length is in the range of 180 mm or more and 480 mm or less, and the width of the ventral part and the dorsal part that contact the wearer's abdomen and back are both 60 mm or more. The width is in the range of 160 mm or less, and the width of the crotch that contacts the wearer's crotch is in the range of 50 mm or more and 140 mm or less. Moreover, the thickness of the absorber 20 can be made thin, for example, in the range of 2.1 mm or more and 5.4 mm or less, by adopting the configuration described below. The entire surface or part of the absorbent body 20 may be embossed. Examples of the shape of the absorbent body 20 in plan view include an hourglass shape, an I-shape, a rectangle, a rounded quadrilateral with four rounded corners, an ellipse, and the like.

(1st sheet, 2nd sheet, and 3rd sheet)
As shown in FIGS. 3 to 5, in the absorbent body 20 of this embodiment, when the absorbent article 50 is worn on the body, the first sheet 60, the second sheet 60, A three-layer laminate (hereinafter also simply referred to as a "three-sheet laminate") in which a second sheet 70 wider than the first sheet 60 and a third sheet 80 wider than the second sheet 70 are laminated in this order in the thickness direction. include. That is, the first sheet 60 is located closest to the wearer's skin, the third sheet 80 is located closest to the wearer's skin, and the second sheet 70 is located between the first sheet 60 and the third sheet 80. The width of each layer gradually increases from the skin side to the non-skin side. When the width of the three-sheet laminate increases from the wearer's skin side to the non-skin side, it fits around the wearer's crotch area (crotch area) and works with the rigid buffer section and buffer line described below to absorb body fluids. Regardless of whether before or after absorption, mobility is improved, fit is improved, and body fluid diffusion is also improved, so the absorption capacity of the three-sheet laminate can be fully utilized. Moreover, the first sheet 60, the second sheet 70, and the third sheet 80 all have skin-side exposed surfaces that directly receive body fluids supplied through the top sheet 10, and the absorbent body 20 as a whole can improve body fluid diffusivity.

The first sheet 60, the second sheet 70, and the third sheet 80 each have a skin-side hydrophilic nonwoven fabric (not shown) located on the skin side, and a skin-side hydrophilic nonwoven fabric (not shown) located on the non-skin side of the skin-side hydrophilic nonwoven fabric. A non-skin-side hydrophilic non-woven fabric (not shown) disposed opposite to the non-woven fabric, and SAP intermediate layers 63, 73, 83 provided between them that firmly support a superabsorbent polymer, and containing fluff pulp. It is not a super absorbent sheet. Note that in FIGS. 5 and 7, illustrations of the skin-side hydrophilic nonwoven fabric and the non-skin side hydrophilic nonwoven fabric are omitted. By making the absorbent body 20 of this embodiment a three-layer laminate of superabsorbent sheets, it is possible to make the absorbent body 20 and the absorbent article 50 thinner. Details of the skin-side and non-skin-side hydrophilic nonwoven fabrics and the SAP intermediate layers 63, 73, and 83 will be described later.

The plan view shapes of the first sheet 60, the second sheet 70, and the third sheet 80 are all rectangular, but are not limited to this embodiment. Examples include rounded rectangles and ellipses. Although the first sheet 60, the second sheet 70, and the third sheet 80 have the same shape in plan view, they are not limited to this embodiment, and may have different shapes in plan view. The first sheet 60, second sheet 70, and third sheet 80 of this embodiment are laminated so that each width direction center line and each length direction center line overlap in the thickness direction, but the present invention is not limited to this. First, the layers may be stacked such that at least one of the center lines in the width direction and the center lines in the length direction do not overlap in the thickness direction. Furthermore, the first sheet 60, the second sheet 70, and the third sheet 80 of this embodiment are configured so that the length increases stepwise from the skin side to the non-skin side. may have the same length.

(rigid buffer)
As shown in FIG. 3, the first sheet 60 is provided with a pair of first rigid buffer sections 61 and 62. The first rigid buffer sections 61 and 62 are partially circular in plan view, in which the basis weight of the superabsorbent polymer is set to be lower than the surrounding area (hereinafter also referred to as "normal distribution area") in the SAP intermediate layer 63 of the first sheet 60. This is an arc-shaped area. By making the first rigid buffer parts 61 and 62 have a lower basis weight than the normal dispersion area, the degree of freedom of deformation of the absorbent body 20 due to the first rigid buffer parts 61 and 62 is increased. The first rigid buffer portions 61 and 62 are located approximately in the center of the first sheet 60 in the length direction, and are provided in partial circles at approximately symmetrical positions on both sides in the width direction with the longitudinal center line as the axis of symmetry. The arch wires are provided so as to face each other in a convex manner in the width direction. Further, the first rigid buffer sections 61 and 62 are configured to have substantially the same planar shape, radius of curvature, length, and width, but may be configured to have different shapes. The first rigid buffer portions 61 and 62 may have a crescent shape or the like in plan view. Further, instead of the first rigid buffer parts 61 and 62 having a partially arcuate linear shape, first rigid buffer parts 61 and 62 having a figure shape may be provided which are convex and facing each other from both sides in the width direction at the central part in the length direction. , gourd shape, hourglass shape, etc.

The pair of second rigid buffer sections 71 and 72 of the second sheet 70 have the same configuration and modification as the first rigid buffer sections 61 and 62. In a preferred embodiment, the length (the length obtained by extending the partially arcuate line into a straight line) and width are larger than those of the first rigid buffer sections 61 and 62. According to this embodiment, the degree of freedom of deformation of the absorber 20 due to the first rigid buffer sections 61 and 62 is improved. The pair of third rigid buffer sections 81 and 82 of the third sheet 80 have the same configuration and modification as the first rigid buffer sections 61 and 62. In a preferred embodiment, the length (the length obtained by extending the partially arcuate line into a straight line) and width are larger than the second rigid buffer parts 71 and 72. According to this embodiment, the degree of freedom of deformation of the absorber 20 due to the second rigid buffer sections 71 and 72 is improved.

By providing the first rigid buffer parts 61, 62, the second rigid buffer parts 71, 72, and the third rigid buffer parts 81, 82 (hereinafter also collectively referred to as "three-sheet rigid buffer parts"), it is possible to wear the When a wearer wears the absorbent article 50, the wearer's crotch area is affected in both width directions, mainly due to the difference in the basis weight of the superabsorbent polymer between the three-sheet rigid cushioning section and the surrounding normal dispersion area. Since the absorbent body 20 deforms appropriately along the edge to correspond to the wearer's crotch region, the fit of the absorbent body 20 and, by extension, the absorbent article 50 is improved.

In another preferred embodiment, as shown in FIG. 3, when the three-sheet laminate is seen through in the thickness direction, the outer edges in the width direction of the second rigid buffer parts 71 and 72 are the same as those of the first rigid buffer part 61. , 62 in the width direction, and the outer edges in the width direction of the third rigid buffer parts 81 and 82 are located further in the width direction than the outer edges in the width direction of the second rigid buffer parts 71 and 72. Located on the outside in the width direction. According to this embodiment, the range of motion of the three-sheet rigid buffer section is increased without impairing the strength of the absorbent body 20, and deformation according to the body shape of the wearer is facilitated.

The first rigid buffer parts 61, 62, the second rigid buffer parts 71, 72, and the third rigid buffer parts 81, 82 each have a basis weight of the superabsorbent polymer in a range of 60 g/ ^m2 or less or 10 g/ ^m2 or more. The range is 40g/ ^m2 or less, the radius of curvature is selected from the range of 360mm to 830mm, or the range of 440mm to 780mm, and the length when the partial arc wire is stretched linearly is 150mm to 450mm, or The width is selected from the range of 210 mm or more and 390 mm or less, and the width is selected from the range of 10 mm or more and 45 mm or less, or 12 mm or more and 20 mm or less. When the basis weight of the superabsorbent polymer is within the above-mentioned range, the range of motion of the three-sheet rigid buffer section becomes relatively large even after absorbing body fluids, and the absorbent body 20 becomes easy to deform to match the wearer's body shape. When the radius of curvature is within the above-mentioned range, the three-sheet rigid cushioning section can easily follow both widthwise edges of the wearer's crotch region. When the length and width are within the above ranges, the absorbent body 20 can be appropriately deformed without sacrificing the strength of the absorbent body 20.

(Lamination area ratio)
The first rigid buffer section 61 has a region X that overlaps with the second rigid buffer section 71 in the thickness direction, and similarly, the first rigid buffer section 62 has a region X that overlaps with the second rigid buffer section 72 in the thickness direction. It has an X. That is, the region X is a part of the first rigid buffer section 61 or the first rigid buffer section 62. The second rigid buffer section 71 has a region Y that overlaps with the third rigid buffer section 81 in the thickness direction, and similarly, the second rigid buffer section 72 has a region Y that overlaps with the third rigid buffer section 82 in the thickness direction. It has Y. That is, the region Y is a part of the second rigid buffer section 71 or the second rigid buffer section 72.

In the present embodiment, the region It is a band-shaped area that extends in a partially arcuate line. Similarly, in this embodiment, in the region Y, each widthwise outer edge of the second rigid buffer sections 71 and 72 overlaps each widthwise inner edge of the third stiffness buffer section 81 and 82 in the thickness direction, This is a band-shaped region extending in a partially arcuate shape in the length direction. In this way, the first rigid buffer parts 61 and 62 and the second rigid buffer parts 71 and 72 partially overlap each other on both widthwise outer sides of the first rigid buffer parts 61 and 62, and the second rigid buffer parts 71 and , 72 and the third rigid buffer parts 81, 82 partially overlap on both widthwise outer sides of the second rigid buffer parts 71, 72, so that when the absorbent body 20 deforms, these deform in conjunction with each other. Therefore, the fit can be improved without causing discomfort.

In this specification, the area of region X (planar view area, the same applies hereinafter) is a ratio to the area of the first rigid buffer sections 61 and 62, and is expressed as the lamination area ratio by the following formula. Here, the first rigid buffer area is the area of the first rigid buffer part 61 or the area of the first rigid buffer part 62, and these areas are also referred to as "one unit area."
Lamination area ratio (%) = (area of region X/area of first rigid buffer part) x 100
Further, the area of the region Y is a ratio to the area of the second rigid buffer portions 71 and 72, and is expressed as the lamination area ratio by the following formula. Here, the second rigid buffer area is the area of the second rigid buffer part 71 or the area of the second rigid buffer part 72, and these areas are also referred to as "one unit area."
Lamination area ratio (%) = (area of region Y/area of second rigid buffer part) x 100
Here, the area of region ) can be used to find it.

In this embodiment, the lamination area ratios of region X and region Y are each 30% or more and 65% or less. When the lamination area ratio of the region X and the region Y is within the above-mentioned range, the interlocking properties when the three-sheet rigid buffer section deforms are enhanced, and a good fit without discomfort can be obtained. If the lamination area ratio of region X and/or region Y is less than 30%, the degree of freedom of deformation decreases and there is a tendency that good fit cannot be obtained. If the area of region There is a tendency that a good fit cannot be obtained.

(buffer line)
In this embodiment, as shown in FIG. 6, the absorbent body 20 includes a fold-shaped buffer line extending linearly from one end in the length direction to the other end in the length direction. The buffer line is a central buffer line A (hereinafter also simply referred to as "buffer line A") extending in the length direction from the center in the width direction in at least one of the first sheet 60, the second sheet 70, and the third sheet 80. ), one end buffer line B extending in the length direction from near one end in the width direction (hereinafter simply referred to as "buffer line B"), and the other end buffer line B extending in the length direction from near the other end in the width direction (hereinafter simply referred to as "buffer line B"). (also referred to as "buffer line C"). Here, the buffer line B and the buffer line C may each be one or more. Moreover, one or more buffer lines B and/or buffer lines C may be provided at different distances in the width direction from the center line in the width direction at the same position as the buffer line A.

FIG. 6 is a schematic plan view showing the absorbent body 20 in which at least one of the buffer line A, the buffer line B, and the buffer line C is provided on the first sheet 60, the second sheet 70, and the third sheet 80. It is. As shown in FIG. 6(a), the first sheet 60 has one buffer line A. As shown in FIG. As shown in FIG. 6(b), the second sheet 70 has one buffer line A, one buffer line B, and one buffer line C. The buffer line B and the buffer line C are provided at symmetrical positions in the width direction with the buffer line A (or the center line in the width direction) as an axis of symmetry. As shown in FIG. 6(c), the third sheet 80 has one buffer line A, two buffer lines B, and two buffer lines C. The buffer lines B include an outer buffer line B located on the outer side in the width direction and an inner buffer line B located on the inner side in the width direction. Similarly, the buffer lines C include an outer buffer line C located on the outer side in the width direction and an inner buffer line C located on the inner side in the width direction. The outer buffer line B and the outer buffer line C are provided at symmetrical positions in the width direction with the buffer line A (or the center line in the width direction) as the axis of symmetry, and the inner buffer line B and the inner buffer line C are They are provided at symmetrical positions in the width direction with the buffer line A (or the center line in the width direction) as the axis of symmetry.

In a preferred embodiment, as shown in FIG. 7(a), in a three-sheet stack, the first sheet 60 is provided with a buffer line A, the second sheet 70 is provided with a buffer line A, and the second sheet 70 is provided with a buffer line A. A buffer line B and a buffer line C are provided along the edges on both sides in the width direction of the first sheet 60, and a buffer line A is provided on the third sheet 80, and when the three-sheet laminate is seen through, An inner buffer line B and an inner buffer line C are provided so as to overlap in the thickness direction with the edges on both sides in the width direction of the first sheet 60, and outer buffer lines B and C are provided along the edges on both sides in the width direction of the second sheet 70. An outer buffer line C is provided.

A modification of the absorber 20 shown in FIG. 7(a) is shown in FIG. 7(b). In FIG. 7, illustration of the hydrophilic nonwoven fabrics on the skin side and the non-skin side included in the first sheet 60, the second sheet 70, and the third sheet 80 is omitted. As described above, the first sheet 60 constituting the absorber 20 has the buffer line A together with the first rigid buffer sections 61 and 62, and the second sheet 70 has the buffer line A along with the second rigid buffer sections 71 and 72. The third sheet 80 has one buffer line B and one buffer line C, and the third sheet 80 has a buffer line A, two buffer lines B, and two buffer lines C together with the third rigid buffer parts 81 and 82. There is.

As shown in FIG. 7(b), when the absorbent article 50 is worn on the body, the absorbent core 20 faces the wearer's crotch area via the top sheet 10 and deforms to match the shape of the crotch area. At this time, the first rigid buffer parts 61, 62, the second rigid buffer parts 71, 72, and the third rigid buffer parts 81, 82 each have a width starting from the vicinity of the non-skin side surface of the skin-side hydrophilic nonwoven fabric (not shown). spread in the direction. Although this also sufficiently improves the fit of the absorber 20 to the wearer's crotch area, here, the buffer line A provided on the first sheet 60, the second sheet 70, and the third sheet 80, the buffer line B and buffer line C in a zigzag manner to deform the absorbent body 20 to match the shape of the wearer's crotch area. As a result, the absorbent article 50 equipped with the absorbent body 20 can closely fit the wearer's crotch region, and can achieve a very good fit as if it were not worn.

(Hydrophilic nonwoven fabric)
As the hydrophilic nonwoven fabric used for the skin side and non-skin side of the first sheet 60, second sheet 70, and third sheet 80, any one commonly used in this field can be used, such as thermal bond nonwoven fabric, Examples include spunbond nonwoven fabrics, airlaid nonwoven fabrics, air-through nonwoven fabrics, pulp-containing nonwoven fabrics, and the like. The basis weight of the hydrophilic nonwoven fabric is in the range of 20 g/m ² or more and 80 g/m ² or less. Among these hydrophilic nonwoven fabrics, air-through nonwoven fabrics are preferred from the viewpoint of body fluid diffusivity and strength. The thickness of the fibers constituting the air-through nonwoven fabric is, for example, in the range of 1.6 dtex or more and 14 dtex or less, 1.8 dtex or more and 9.0 dtex or less, or 2.0 dtex or more and 6.0 dtex or less.

(SAP middle layer)
The SAP intermediate layer 63 includes first rigid buffer sections 61 and 62 and a normal dispersion area (not shown) provided around the first rigid buffer sections 61 and 62. The SAP intermediate layer 73 includes second rigid buffer sections 71 and 72 and a normal dispersion area (not shown) provided around the second rigid buffer sections 71 and 72. The SAP intermediate layer 83 includes first rigid buffer sections 81 and 82 and a normal dispersion area (not shown) provided around the first rigid buffer sections 81 and 82. The superabsorbent polymer contained in the SAP intermediate layer 63, 73, 83 is not particularly limited as long as it can absorb body fluids such as urine and prevent backflow of body fluids, and polyacrylates, polyasparagine, etc. Examples include acid salts, (starch/acrylic acid) graft copolymers, (acrylic acid/vinyl alcohol) copolymers, (isobutylene/maleic anhydride) copolymers, and saponified products thereof. Among these, from the viewpoint of absorption per weight, polyacrylates are preferred, and sodium polyacrylate is more preferred. The basis weight of the superabsorbent polymer in the normal spraying area is, for example, in the range of 150 g/m ² or more and 800 g/m ² or less. The rigid buffer portions 81 and 82 have a lower basis weight than that.

In addition, by avoiding the use of finely powdered superabsorbent polymers that have poor fluidity as powder, the basic performance regarding absorption is improved, and the roughness that occurs when the superabsorbent sheets 60, 70, and 80 become hard can be improved. From the viewpoint of reducing the tactile sensation, it is preferable to use a particulate superabsorbent polymer having a medium particle size as the superabsorbent polymer. The median particle diameter is, for example, in the range of 50 μm or more and 600 μm or less, or in the range of 100 μm or more and 500 μm or less.

The superabsorbent polymer is firmly supported on the SAP intermediate layer 63, 73, 83 using a hot melt adhesive. In addition, from the viewpoint of not inhibiting the absorbency of the superabsorbent polymer and not impairing the feel when worn, the content of the hot melt adhesive is, for example, in a range of 10 g/m ² or less. As hot melt adhesives, those having a melting point of 100°C or higher and 180°C or lower can be used without particular limitation.For example, synthetic rubber hot adhesives such as styrene-butadiene-styrene copolymers, styrene-isoprene-styrene copolymers, etc. Examples include melt adhesives and olefin hot melt adhesives such as ethylene-vinyl acetate copolymers. As a method for applying the hot melt adhesive, known methods such as a curtain coating method or a spiral method in which a molten hot melt adhesive is applied from a nozzle in a non-contact manner, and a slot method in which a molten hot melt adhesive is applied in a contact manner can be used.

In this embodiment, a carrier sheet (not shown) that wraps the entire absorbent body 20 may be used from the viewpoint of preventing the superabsorbent polymer from falling off and stabilizing the shape of the absorbent body 20. The base material of the carrier sheet may be any material as long as it has hydrophilic properties, and examples thereof include tissue, absorbent paper, hydrophilic nonwoven fabrics such as air-laid nonwoven fabrics, and the like. When a plurality of carrier sheets are provided, the base materials of the plurality of carrier sheets may be the same or different.

(back seat)
The backsheet 30 may be formed using a liquid-impermeable base material that prevents body fluids held by the absorbent core 20 from wetting clothing, and examples of the base material include, for example, a resin film, Examples include composite sheets that are laminates of resin films and nonwoven fabrics. The manufacturing method of the nonwoven fabric used in the composite sheet is not particularly limited, and examples include spunbond nonwoven fabric, meltblown nonwoven fabric, composite nonwoven fabric that is a laminate of spunbond nonwoven fabric/meltblown nonwoven fabric, and spunbond nonwoven fabric/meltblown nonwoven fabric/spunbond nonwoven fabric. Examples include a composite nonwoven fabric that is a laminate, a composite material that is a laminate of two or more of these, and the like. Further, examples of the resin film include films of polyester, polyvinyl alcohol, polyethylene, polypropylene, etc., and composite films of polyethylene and polypropylene.

The basis weight of the back sheet 30 is, for example, in the range of 15 g/m ² or more and 40 g/m ^{2 or} less from the viewpoint of strength and workability. Further, from the viewpoint of preventing stuffiness when worn, the back sheet 30 is preferably breathable. To impart air permeability to the backsheet 30, for example, a method of adding a filler to a resin film, a method of embossing the backsheet 30 for perforation, etc. can be used. Here, the filler includes calcium carbonate, and the filler can be blended according to a known method.

(3D gathers)
As shown in FIG. 1, the absorbent article 50 is provided at both ends of the skin side of the top sheet 10 along the longitudinal direction of the absorbent article 50, for example, in order to prevent side leakage of bodily fluids excreted by the user. A pair of three-dimensional gathers 40 is provided nearby. In the three-dimensional gathers 40 of this embodiment, one end in the width direction is fixed near both ends of the skin side of the back sheet 30, a middle part in the width direction is fixed near both ends of the skin side of the top sheet 10, and the width thereof The other end in the direction is a free end 40a that is not fixed to the top sheet 10. When an elastic stretchable member (not shown) is disposed near the free end 40a along the longitudinal direction, the free end 40a is given erectability and can be deformed to suit the body shape of the wearer.

The fixing position of one end in the width direction of the three-dimensional gathers 40 is not limited to this embodiment. For example, the position where the three-dimensional gathers 40 are fixed at one end in the width direction is not limited to the present embodiment. Examples include the vicinity of both ends in the width direction of the bag that is joined as a whole and stores the absorbent body 20 therein, and the vicinity of both ends in the width direction of the skin side of the top sheet 10. Note that the absorbent article 50 of this embodiment also includes an embodiment that does not include the three-dimensional gathers 40.

As the sheet member constituting the three-dimensional gathers 40, water-repellent and/or liquid-impermeable nonwoven fabrics made of hydrophobic fibers can be used without particular limitation.For example, spunbond nonwoven fabrics, melt-blown nonwoven fabrics, spunbond nonwoven fabrics/ Examples include composite nonwoven fabrics that are laminates of melt-blown nonwoven fabrics/spunbond nonwoven fabrics. As the elastic stretchable member, common products in this field can be used without particular limitation, and examples thereof include polyurethane thread, band-shaped polyurethane film, thread-shaped or band-shaped natural rubber, and the like.

<Method for manufacturing absorbent articles>
The absorbent article 50 can be manufactured by a known manufacturing method, but for example, a step of arranging the absorber 20 between the top sheet 10 and the back sheet 30, and a step of disposing the top sheet 10 and the back sheet 30 partially or completely. Manufacturing including a process of fixing using hot melt adhesive, heat embossing, ultrasonic embossing, high frequency embossing, etc. over the circumference, and a process of installing three-dimensional gathers 40 at predetermined positions of the back sheet 30 and top sheet 10. There are several methods. When the absorbent article 50 is a urine absorbing pad or a light incontinence pad, it may be individually wrapped in a package and then folded into three in the longitudinal direction. Further, leg gathers, waist gathers, side flaps, etc. can be provided as necessary.

Although the present invention has been described above using the embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope of the invention described in the above embodiments. It will be obvious to those skilled in the art that modifications may be made. Furthermore, it is clear from the claims that forms with such changes or improvements may also be included within the technical scope of the present invention.

Hereinafter, this embodiment will be described in detail by giving Examples and Comparative Examples. Note that this embodiment is not limited to the examples shown below.

(Example 1 and Comparative Examples 1 to 5)
An air-through nonwoven fabric (basis weight 25 g/m ² ) was used as the top sheet, an absorbent body having the configuration shown in Tables 1, 2, and 3 was used as the top sheet, and a breathable polyethylene sheet (basis weight 30 g /m ² ), and a composite nonwoven fabric (basis weight 15 g/m ² ), which is a laminate of spunbond nonwoven fabric/melt blown nonwoven fabric/spunbond nonwoven fabric, was used as the three-dimensional gather. An absorbent article that is a pad type disposable diaper was produced. In Comparative Example 1, as shown in Tables 1 and 2, a fluff pulp absorbent body in which two layers of fluff pulp and a superabsorbent polymer were laminated was used as the absorbent body.

The following evaluations were performed on the pad type disposable diapers of Example 1 and Comparative Examples 1 to 5. The results are shown in Table 4.
[Thickness under load])
The thickness at the center of the absorber under a load of 35 gf/cm ² was measured.
[Monitor fit evaluation]
Regarding the pad-type disposable diapers of Example 1 and Comparative Examples 1 to 5, responses were obtained from monitors from care recipients and caregivers, and the fit and presence or absence of leakage were evaluated.
At a certain facility, with the cooperation of eight care recipient monitors who had a relatively large amount of urine, they were asked to wear the pad type disposable diapers of Example 1 and Comparative Examples 1 to 5, and the fit was evaluated when worn overnight. , continued use for one week, and evaluated based on the following criteria.
When 6 or more people and 8 or less people rated "It doesn't feel strange" as "○", and when 3 or more and 5 or less people rated "It doesn't feel strange" as "△", and "It doesn't feel too strange" is rated as "△". When one or two people rated the test as "less uncomfortable," it was rated "x."
In addition, regarding the presence or absence of leakage, the caregiver monitor checks the leakage status of the cared person monitor, and when 6 or more people and 8 or less people rate ``Leakage is small'', it is rated ``〇'', and ``Leakage is small''. If 3 or more people and 5 or less people rated it as "△", if 1 or 2 people rated it as ``less leakage'', or if no one rated it as ``least uncomfortable'', it would be rated as ``x''. did.

[Absorption rate (repeated absorption rate)]
The pad type disposable diapers of Example 1 and Comparative Examples 1 to 5 were stretched flat and fixed in an expanded state, and a cylindrical absorption speed jig with an inner diameter of 30 mm was installed at the center of the skin side in the width direction and length direction. Then, 150 ml of 0.9% physiological saline was injected each time, and the time until the liquid level was absorbed by the surface of the paper diaper was measured. Three minutes after absorption, the next 150 ml was injected, and the time until absorption was measured in the same manner. This operation was repeated, and the total time required for absorption of 150 ml x 3 times was defined as the absorption rate (seconds). The measurement was performed under a pressure of 35 g/cm ² using the weight of the absorption rate jig.

[Reverse amount]
The pad-type disposable diapers of Example 1 and Comparative Examples 1 to 5 were stretched flat and fixed in an expanded state, and 150 ml of 0.9% physiological saline was added to the widthwise and lengthwise center of the skin side of the pad-type disposable diaper. Water was poured 8 times at 3 minute intervals, and left to stand for 10 minutes after the water injection was completed. A filter paper was placed at the center of the skin side of the pad type diaper in the width direction and length direction, and a weight with a load of 35 g/m ² was placed on top of the filter paper, and the filter paper was allowed to stand for 1 minute. Thereafter, the weight was removed, and the weight of 0.9% physiological saline absorbed by the filter paper was determined from the difference in weight before and after absorption, and was determined as the amount of return (wet back, g).

More specifically, each of the absorbers of Example 1 and Comparative Examples 1 to 6 had the following results.
(Example 1) The absorbent body has a three-sheet laminated structure in which the width of the superabsorbent sheet increases from the skin side to the non-skin side, and a first rigid buffer section, a second rigid buffer section, and a third rigid buffer section. As a result, the absorbent material's comfort and fit have improved.
(Comparative Example 1) The absorber, which is a two-layer laminate of fluff pulp absorbers, is thick and uncomfortable when worn, and after absorption, the first rigid buffer section deforms and collapses under the load of wearing, and leaks. reached.
(Comparative Example 2) An absorbent body with a three-sheet laminated structure in which the width of the superabsorbent sheet is narrowed from the skin side to the non-skin side has poor fit, feels uncomfortable, and cannot be worn properly. The first rigid buffer section could not promote the diffusion of urine, and leakage was observed.
(Comparative Example 3) An absorber in which the first, second, and third rigid cushioning parts do not overlap in the thickness direction has good fit, but wrinkles caused by the first rigid cushioning part appear in the width direction when worn. This occurred, leading to leakage.
(Comparative Example 4) An absorbent body in which the first, second, and third rigid buffer sections completely overlap in the thickness direction causes twisting in the vicinity of the wearer's crotch area after absorption, making the wearer feel even wetter. Absorption was unevenly observed near the center of the crotch of the absorbent material facing the body.
(Comparative Example 5) An absorbent body in which the first, second, and third sheets do not have a central buffer line and an end buffer line swells to the ends in the width direction after absorption, increases rigidity in the working area, and causes discomfort. I became stronger.
(Comparative example 6)
In an absorbent body in which the basis weight of the superabsorbent polymer in the first rigid buffer section is 100 g/ ^m2 , the deformability of the first rigid buffer section is insufficient, resulting in a feeling of discomfort, and body fluid diffusion after repeated absorption is poor, resulting in leakage. reached.

10 Top sheet 20 Absorbent body 30 Back sheet 40 Three-dimensional gathers 40a Free end 50 Absorbent article 60 First sheet 61, 62 First rigid buffer section 63 SAP intermediate layer 70 Second sheet 71, 72 Second rigid buffer section 73 SAP intermediate layer Layer 80 Third sheet 81, 82 Third rigid buffer section 83 SAP middle layer

Claims (6)

An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between them,
The absorber is
A first sheet, a second sheet wider than the first sheet, and a third sheet wider than the second sheet are stacked in this order from the wearer's skin side to the non-skin side. A three-layer laminate is included, and the first sheet, the second sheet, and the third sheet are all superabsorbent sheets in which a superabsorbent polymer is firmly supported between two sheets of hydrophilic nonwoven fabric. can be,
The first sheet, the second sheet, and the third sheet each face each other in the width direction, extend in an arc shape in the length direction, and have a higher area weight of the superabsorbent polymer than other areas. a pair of first rigidity buffering parts, a pair of second rigidity buffering parts, and a pair of third rigidity buffering parts, each of which has a low stiffness,
The first rigid buffer section and the second rigid buffer section have a region X that overlaps in the thickness direction, and the second rigid buffer section and the third rigid buffer section have a region Y that overlaps in the thickness direction. and the absorbent body further includes a fold-shaped buffer line extending linearly from one end in the length direction to the other end in the length direction, and the buffer line is connected to the first sheet, the second sheet, and An absorbent article characterized in that at least one of the third sheets has a central buffer line provided at the center in the width direction and/or an end buffer line provided near the ends in the width direction. The first rigid buffer section, the second rigid buffer section, and the third rigid buffer section each have a basis weight of the superabsorbent polymer of 60 g/m ² or less, a radius of curvature of 360 mm or more and 830 mm or less, and a length of 150 mm or more and 450 mm or less. , and a width of 10 mm or more and 45 mm or less. The area in plan view of the region The absorbent article according to claim 1 or 2, which has a content of 65% or less. The length and width of the second rigid buffer section are respectively greater than the length and width of the first rigid buffer section, and the length and width of the third rigid buffer section are respectively equal to the length of the second rigid buffer section. and the width of the absorbent article according to any one of claims 1 to 3. The outer edge in the width direction of the second rigid buffer part is located on the outer side in the width direction than the outer edge in the width direction of the first rigid buffer part, and the outer edge in the width direction of the third rigid buffer part is The absorbent article according to any one of claims 1 to 4, wherein the absorbent article is located on the outer side in the width direction than the outer edge in the width direction of the second rigid buffer portion. The absorbent article according to any one of claims 1 to 5, wherein the hydrophilic nonwoven fabric is an air-through nonwoven fabric.

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