JP7372854B2 - absorbent articles - Google Patents

Description

The present invention relates to absorbent articles.

Generally, an absorbent article includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between them. Body fluids such as urine are absorbed into the absorbent body through the top sheet. 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.

As an absorbent material in an absorbent article, fluff pulp and a super absorbent polymer (hereinafter also referred to as "SAP") are generally used in combination. On the other hand, with the aim of further improving wearing comfort, appearance, feel, and urine backflow prevention properties, a superabsorbent sheet (hereinafter referred to as "SAP Various types of sheets (also referred to as "sheets") have been proposed.

Patent Document 1 describes first and second sheets each having one surface coated with an adhesive, and sheets extending in the longitudinal direction and arranged in a stripe shape between the adhesive coated surfaces of the first and second sheets. a plurality of SAP layers, the adhesive is intermittently applied on the adhesive-coated surface of the second sheet in the area facing the SAP layer, and the adhesive is applied directly on both sides of the SAP layer in the width direction without intervening the SAP layer. A superabsorbent sheet is disclosed in which an adhesive is continuously applied in the longitudinal direction on each adhesive-applied surface of the first and second sheets that face each other.

Patent Document 2 discloses a first absorbent body and a second absorbent body disposed on one side and the other side in the width direction between a top sheet and a back sheet, respectively, and containing SAP, and the first and second absorbent bodies are two sheets. and SAP disposed therebetween, the first and second absorbent bodies each have first and second folds extending in the longitudinal direction, and the first and second folds are opposed to each other. A superabsorbent sheet is disclosed.

Japanese Patent Application Publication No. 2006-158676 JP2013-042882A

However, in Patent Document 1 and many other superabsorbent sheets, the base nonwoven fabric and the superabsorbent polymer are fixed using a hot melt adhesive, which makes them hard to the touch and reduces the feeling of wearing. There was a problem in that it caused a sense of discomfort because it was not possible to have sex. In addition, compared to conventional absorbents made of fluff pulp and superabsorbent polymers, many superabsorbent sheets have superabsorbent polymers fixed to the base nonwoven fabric by adhesive means, resulting in superabsorbent properties. Since the polymer is present in a high density, it takes a long time to absorb the urine and has poor urine diffusivity, so it is not fully satisfactory from the viewpoint of absorbency.

Since the superabsorbent sheet of Patent Document 2 has the above-mentioned predetermined structure, the fit to the crotch is improved, but the hard feel characteristic of superabsorbent sheets is not improved, and the feeling of wearing is poor. It wasn't quite satisfying. Further, the superabsorbent sheet of Patent Document 2, like the superabsorbent sheet of Patent Document 1, did not have sufficiently satisfactory absorbency.

The present invention has been made in view of the above circumstances, and aims to provide an absorbent body that does not contain fluff pulp and has good absorbency and wear comfort, and an absorbent article including the absorbent body.

The inventor of the present invention conducted extensive research in view of the above problems. As a result, we discovered that the above problems could be solved by devising the form of the nonwoven fabric that serves as the base and the method of supporting the superabsorbent polymer, and by appropriately folding and arranging the superabsorbent sheet, and completed the present invention. reached. Specifically, the present invention provides, for example, the following embodiments.

(1) A first aspect of the present invention provides a liquid-permeable top sheet, a liquid-impermeable back sheet disposed opposite to the top sheet, and a space between the top sheet and the back sheet. An absorbent article comprising: an absorbent body arranged in the absorbent body, the absorbent body comprising a superabsorbent sheet and a hydrophilic sheet, the superabsorbent sheet having a raised surface and a non-raised surface. The hydrophilic sheet includes a base nonwoven fabric, a cover nonwoven fabric that covers a part of the raised surface of the base nonwoven fabric, and a superabsorbent polymer fixedly supported between the raised fibers of the base nonwoven fabric, and the hydrophilic sheet includes a base nonwoven fabric. The cover nonwoven fabric covers the entire raised surface and the non-skin side surface of the cover nonwoven fabric, and the cover nonwoven fabric is disposed at the center in the width direction of the base nonwoven fabric, and the cover nonwoven fabric has a widthwise dimension of the base nonwoven fabric. A non-existence area of the superabsorbent polymer is provided on the raised surface of the superabsorbent sheet that overlaps with the cover nonwoven fabric in the thickness direction, and has a ratio of 5% to 50% of the size of the absorbent sheet. is an inner three-fold shape with the non-raised surface of the base nonwoven fabric facing inside, with an opening between both end faces in the width direction of the superabsorbent sheet, and the non-raised surface of the base nonwoven fabric facing the top sheet. The hydrophilic sheet has a groove portion having a bottom surface, and is stretched in the width direction so that both ends of the hydrophilic sheet in the width direction cover the opening of the groove portion and overlap in the thickness direction, and the overlapping width dimension is: 5% or more and 50% or less of the width dimension of the absorbent body folded in thirds, and the thickness of the absorbent body measured under a load of 35 g/cm ² in a flat state before folded in thirds is 1 0 mm or more and 4.0 mm or less, and the thickness measured under a load of 35 g/cm ² is 30% or more and 70% or less of the thickness measured under no load. It is an article.

(2) A second aspect of the present invention is the absorbent article according to (1), wherein the cover nonwoven fabric is an air-through nonwoven fabric, has a thickness of 0.1 mm or more and 3.0 mm or less, and has a basis weight is 10 g/m ² or more and 60 g/m ² or less.

(3) A third aspect of the present invention is the absorbent article according to (1) or (2), in which the abundance ratio of the superabsorbent polymer in the folded portion of the absorbent body is higher than that in the non-folded portion. It is characterized by being smaller than the abundance ratio of the superabsorbent polymer.

(4) A fourth aspect of the present invention is the absorbent article according to any one of (1) to (3), wherein the base nonwoven fabric is an air-through nonwoven fabric, and has a basis weight of 20 g/m ² or more and 120 g /m ² or less, the thickness is 0.3 mm or more and 8.0 mm or less, and the thickness of the fibers constituting the base nonwoven fabric is 1.8 dtex or more and 9.0 dtex or less. be.

(5) A fifth aspect of the present invention is the absorbent article according to any one of (1) to (4), wherein the superabsorbent polymer has a basis weight of 150 g/m ² or more and 1000 g/m ² It is characterized by the following.

(6) A sixth aspect of the present invention is the absorbent article according to any one of (1) to (5), wherein the hydrophilic sheet has a basis weight of 10 g/m ² or more and 60 g/m ² It is characterized by being the following hydrophilic nonwoven fabric or tissue paper.

Therefore, according to the present invention, it is possible to provide an absorbent body that does not contain fluff pulp and has good absorbency and wearability, and an absorbent article including the absorbent body.

1 is a plan view schematically showing the structure of an absorbent article according to a first embodiment of the present invention. FIG. 2 is a schematic perspective view of a base nonwoven fabric and a cover nonwoven fabric in the absorbent body of the present embodiment. FIG. 2 is a cross-sectional view in the width direction of a superabsorbent sheet in the absorbent body of the present embodiment. FIG. 2 is a schematic cross-sectional view in the width direction of the absorber of this embodiment. FIG. 7 is a schematic cross-sectional view in the width direction of an absorber according to another embodiment.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings, but these are provided for the purpose of illustration and the present invention is not limited thereto. Note that throughout the description of the embodiments, the same elements are denoted by the same reference numerals, and the description given for the first time is used. Further, in this specification, it is defined as follows. The longitudinal direction of the absorbent body 1 or the absorbent article 50 is the direction indicated by the symbol Y in the figure, which extends from the front and back of the wearer when the absorbent article 50 including the absorbent body 1 is worn. The width direction of the absorbent body 1 and the absorbent article 50 is a direction indicated by the symbol X in the figure, which is substantially orthogonal to the longitudinal direction. The thickness direction of the absorbent core 1 and the absorbent article 50 is the direction indicated by the symbol Z in the figure, in which the respective constituent members are laminated. The skin side of the absorbent body 1 and the absorbent article 50 refers to the surface that contacts or faces the skin of the wearer of the absorbent article 50, and the non-skin side refers to the surface that contacts the skin of the wearer of the absorbent article 50. This is the surface that comes into contact with clothing or the surface that faces clothing. Body fluids refer to fluids discharged from the body, such as urine, blood, and water in loose stools.

<Absorbent article>
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 longitudinal and widthwise dimensions 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 in the range of 50 mm or more and 500 mm or less, respectively. By adjusting the dimensions of the absorbent article 50 within the above range, absorbent articles for various uses and sizes can be obtained.

More specifically, the absorbent article 50 of this embodiment is an absorbent article including the absorbent core 1 of this embodiment. FIG. 1 is a plan view of the absorbent article 50 of this embodiment as viewed from the top sheet 25 side. As shown in FIG. 1, the absorbent article 50 includes a liquid-permeable top sheet 25 disposed on the body side, a liquid-impermeable back sheet 30 disposed opposite to the top sheet 25, and a top sheet 25 and an absorbent body 1 disposed between the backsheet 30 and the backsheet 30. As a result, the absorbent body 1 has a structure in which it is sandwiched between the top sheet 25 and the back sheet 30, and body fluids such as urine are absorbed into the absorbent body 1 through the top sheet 25. In addition, leg gathers, waist gathers, side flaps, etc. can be provided as appropriate depending on the use and type of the absorbent article 50.

In the absorbent article 50 of the present embodiment, the absorbent core 1 does not contain fluff pulp, suppresses the return of body fluids such as urine, maintains a smooth and comfortable touch, and has excellent absorbency of body fluids and wearability. It also includes embodiments that have a good fit and do not feel uncomfortable while being worn. In particular, when the absorbent body 1 does not contain fluff pulp and contains a predetermined superabsorbent sheet 10, the softness of the absorbent body 1 is maintained, and the fit and wearing feeling are significantly improved.

Hereinafter, each of the sheet-like or plate-like constituent members will be explained in more detail in the order of the top sheet 25, the absorbent core 1, the back sheet 30, and the three-dimensional gathers 40. Note that these constituent members may have a three-dimensional shape other than sheet-like or plate-like.

(Top sheet)
The top sheet 25 is a liquid-permeable sheet-like member that allows body fluids to pass quickly toward the absorbent core 1, and is disposed opposite to the backsheet 30 with the absorbent core 1 in between. Since the top sheet 25 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 a hydrophilic nonwoven fabric, a composite nonwoven fabric that is a laminate of hydrophilic nonwoven fabrics of the same type or different types, an open film such as an open polyethylene film, and a foamed film such as urethane foam. Hydrophilic nonwoven fabrics are produced using, for example, synthetic fibers made of synthetic resins such as polypropylene and polyethylene, recycled fibers such as rayon, and natural fibers such as cotton. It can be obtained by processing using a known method.

Further, the top sheet 25 may be embossed or perforated on the surface in order to improve liquid permeability. As a method for performing these embossing and perforation processes, known methods can be used without any restriction. Further, in order to reduce irritation to the skin, the top sheet 25 may contain a lotion, an antioxidant, an anti-inflammatory component, a pH adjuster, an antibacterial agent, a humectant, and the like. From the viewpoints of strength, workability, and liquid return amount, the basis weight of the top sheet 25 is, for example, in the range of 15 g/m ² or more and 40 g/m ² or less. The shape of the top sheet 25 is not particularly limited, and may be any shape that covers the absorbent body 1 and is required to guide body fluids to the absorbent body 1 without leakage.

(Absorber)
The absorbent body 1 of the present embodiment can be used for various purposes, such as tape-type absorbent articles, pants-type absorbent articles, urine absorbing pads, light incontinence pads, etc., regardless of whether it is for adults or infants. It can be used in various absorbent articles.

As shown in FIGS. 2 to 5, the absorbent body 1 of this embodiment includes a superabsorbent sheet 10, the raised surface of the superabsorbent sheet 10 (or the base nonwoven fabric 11), and the entire non-skin side surface of the cover nonwoven fabric 15. and a hydrophilic sheet 20 that covers and adheres to these. The absorbent body 1 in FIG. 4 is made by folding a superabsorbent sheet 10 in thirds with the non-raised surface of the base nonwoven fabric 11 facing inside, with both widthwise ends facing the center, and the folded corners have a smooth cross-sectional view. The superabsorbent sheet 10 has a curved shape, and both ends are folded back toward the center so that the cross section of the superabsorbent sheet 10 is approximately C-shaped (however, the C-shaped is rotated 90 degrees to the left). It is arranged. In addition, the absorbent body 1 in FIG. 5 is constructed by folding the superabsorbent sheet 10 in thirds with the non-raised surface of the base nonwoven fabric 11 facing inside, with both widthwise ends facing the center, and then cross-sectional view of the folded corner. has a substantially right-angled shape, and in the cross section of the superabsorbent sheet 10, one end in the width direction of a substantially U-shape and the other end in the width direction of a substantially inverted U-shape (a substantially U-shape reversed in the left-right direction) are widthwise. They are arranged in such a way that both ends are folded back toward the center so that they face each other in the same direction. The absorbent bodies 1 shown in FIGS. 4 and 5 are equivalent in terms of body fluid absorbency, body fluid retention, flexibility, texture, and the like.

The absorbent body 1 of this embodiment has a groove portion 21 formed by folding the groove inward. More specifically, the groove part 21 has an opening between both ends of the superabsorbent sheet 10 in the width direction, a bottom part of the non-raised surface of the base nonwoven fabric 11 facing the top sheet 25, and an opening in the width direction of the superabsorbent sheet 10. It extends in the longitudinal direction approximately at the center. The grooves 21 function, for example, like slits, and cooperate with the skin-side top sheet 25 and the hydrophilic sheet 20 to form a body fluid diffusion layer, further increasing the absorption rate, and dispersing body fluids from the top sheet 25. Reduces the return to the side. Therefore, according to the absorbent body 1 of this embodiment, even if it does not contain fluff pulp, there is very little rough feeling derived from the superabsorbent polymer 12, and the overall flexibility is good, so that urine This prevents the skin from returning, making it easier to maintain a smooth texture.

The ratio of the distance C between both ends of the superabsorbent sheet 10 to the widthwise dimension D of the absorbent body 1 after folding in three (FIGS. 4 and 5) is, for example, in the range of 10% or more and 50% or less. Or in the range of 13% or more and 47% or less. By setting the distance C between both ends of the superabsorbent sheet 10 to the widthwise dimension D of the absorbent body 1 within the above range, the absorption speed of the absorbent body 1 is further improved.

Further, in the absorbent body 1, both widthwise ends of the hydrophilic sheet 20 folded in three are further stretched in the widthwise direction so that both widthwise ends overlap in the thickness direction on the top sheet 25 side of the opening of the groove 21. It is configured. As a result, the openings of the grooves 21 are covered with the overlapping portions of the hydrophilic sheets 20 (hereinafter also referred to as "overlapping regions") (FIGS. 4 and 5). Due to the presence of this overlapping region, the absorbent body 1 has the advantage that the diffusion rate and absorption rate of body fluids are further increased. The width dimension E of the overlapping region in the absorbent core 1 is, for example, in a range of 5% or more and 50% or less of the width dimension D of the absorbent core 1. If it is less than 5%, even if an overlapping region is provided, the effect of improving the diffusion rate and absorption rate of body fluids tends to be insufficient. If it exceeds 50%, the diffusion rate and absorption rate of bodily fluids will not improve, while the hardness of the absorbent body will increase and the fit will tend to deteriorate.

The longitudinal dimension of the absorber 1 is, for example, in the range of 100 mm or more and 800 mm or less, or in the range of 150 mm or more and 500 mm or less. Further, the widthwise dimension D of the absorbent core 1 when folded in three is, for example, in the range of 50 mm or more and 500 mm or less, or in the range of 66 mm or more and 400 mm or less.

The thickness of the absorbent body 1 in a flat state before folding in three, measured under a load of 35 g/cm ² , is, for example, in the range of 1.0 mm or more and 4.0 mm or less, or 1.5 mm or more and 3.8 mm or less. is within the range of By setting the thickness of the absorbent body 1 under a load of 35 g/m ² to be within the above numerical range, the feeling of wearing the absorbent article 50 including the absorbent body 1 can be made even better. Note that the thickness of the absorbent body 1 at this time refers to the thickness of the base nonwoven fabric 11 with the superabsorbent polymer 12 firmly supported on the raised surface and the raised surface of the base nonwoven fabric 11 bonded together in the flat state before folding in three. This means the total thickness of the hydrophilic sheet 20.

In addition, the thickness of the absorbent body 1 measured under a load of 35 g/cm ² in a flat state before folding in thirds is, for example, 30% or more and 70% of the thickness measured in an unloaded state. It is preferably in the following range or in the range of 40% or more and 60% or less. By setting the thickness ratio within the above numerical range, the feeling of wearing the absorbent article 50 including the absorber 1 can be made even better. The thickness may be determined by, for example, the thickness and material of the base nonwoven fabric 11, the cover nonwoven fabric 15, and the hydrophilic sheet 20, the degree of napping on the raised surface of the base nonwoven fabric 11, the average particle size of the superabsorbent polymer 12, etc. Adjustment can be made by appropriately selecting two or more.
Each member constituting the superabsorbent sheet 10 will be explained below.

(Base nonwoven fabric)
FIG. 2 is a schematic perspective view of the base nonwoven fabric 11 and the cover nonwoven fabric 15 used in the absorber 1 of this embodiment. As shown in FIG. 2, one surface of the base nonwoven fabric 11 is in a raised state, and the other surface is in a non-raised state. Therefore, in addition to the inherent bulkiness of the nonwoven fabric, the superabsorbent sheet 10 is given appropriate thickness and softness, providing appropriate cushioning properties and improving the fit when worn. Further, by raising the base nonwoven fabric 11 as described above, the superabsorbent polymer 12 can be dispersed and fixedly supported between the fibers of the raised portion of the base nonwoven fabric 11. Sufficient space is formed around the superabsorbent polymer 12 firmly supported between the nap fibers for the polymer 12 to absorb body fluids and swell, and body fluids are quickly absorbed, so body fluids can be repeatedly absorbed. Even when absorbed, the absorption rate does not easily decrease. Examples of methods for raising one surface of the base nonwoven fabric 11 include a rotary saw blade and a needle punch, and from the viewpoint of in-line productivity and cost, it is preferable to use a method of raising the fluff with a rotary saw blade.

The state of the napping in this embodiment is not particularly limited, and it is sufficient if the napping state can be visually confirmed, but more specifically, the napping rate of the base nonwoven fabric 11 is, for example, in the range of 5% or more and 90% or less, or 8% or less. % or more and 80% or less. Note that the napping rate means the rate of increase in the thickness of the base nonwoven fabric 11 due to the napping process. For example, when the thickness of the base nonwoven fabric 11 before raising is T1, and the thickness of the base nonwoven fabric 11 after raising is T2, the raising rate (%) can be expressed as [(T2-T1)/T1]×100. Can be done. The above thickness is determined by measuring the thickness under no load using a height gauge (manufactured by Mitutoyo Co., Ltd.). Although the other surface of the base nonwoven fabric 11 is a non-raised surface in this embodiment, the present invention is not limited to this, and the fibers may be raised.

The base nonwoven fabric 11 may be, for example, a nonwoven fabric such as an air-through nonwoven fabric, a point bond nonwoven fabric, a spunbond nonwoven fabric, or a meltblown nonwoven fabric, or a laminate of multiple nonwoven fabrics such as a spunbond nonwoven fabric/meltblown nonwoven fabric, a spunbond nonwoven fabric/meltblown nonwoven fabric/spunbond nonwoven fabric, etc. Composite nonwoven fabrics, etc., which are bodies, can be mentioned. Among these, air-through nonwoven fabrics are preferred because they are easy to obtain bulk.

The longitudinal dimension of the base nonwoven fabric 11 is, for example, in the range of 100 mm or more and 800 mm or less, or in the range of 150 mm or more and 700 mm or less. The width direction dimension B of the base nonwoven fabric 11 is, for example, in a range of 75 mm or more and 900 mm or less, or in a range of 105 mm or more and 380 mm or less.

The thickness of the base nonwoven fabric 11 is, for example, in the range of 0.3 mm or more and 8.0 mm or less, or in the range of 2.0 mm or more and 6.0 mm or less, from the viewpoint of the balance between wearing comfort and absorption performance. Further, the basis weight of the base nonwoven fabric 11 is, for example, in the range of 20 g/m ² or more and 120 g/m ² or less, or in the range of 30 g/m ² or more and 110 g/m ² or less.

The thickness of the fibers constituting the base nonwoven fabric 11 is, for example, in a range of 1.8 dtex or more and 9.0 dtex or less, or in a range of 2.0 dtex or more and 6.0 dtex or less. By adjusting the thickness of the fibers constituting the base nonwoven fabric 11 within the above numerical range, the superabsorbent polymer 12 is dispersed between the fibers in the raised portion of the base nonwoven fabric 11, making it easier to fix and support the superabsorbent polymer 12. be able to.

(Cover non-woven fabric)
As shown in FIG. 2, a cover nonwoven fabric 15 is arranged on the raised surface of the base nonwoven fabric 11 so as to cover a part of the raised surface of the base nonwoven fabric 11, and the raised surface of the base nonwoven fabric 11 facing the cover nonwoven fabric 15 is A region 14 where no superabsorbent polymer 12 exists (FIGS. 3 to 5). By configuring the superabsorbent sheet 10 having the cover nonwoven fabric 15, when the superabsorbent polymer 12 is firmly supported in the production of the superabsorbent sheet 10 described later, the superabsorbent sheet 10 overlaps with the cover nonwoven fabric 15 in the thickness direction. A region 14 in which the superabsorbent polymer 12 is absent is provided on the raised surface of the flexible sheet 10. Since the superabsorbent polymer 12 is not present in the non-existing area 14, the non-existing area 14 plays the role of a pseudo slit, improving the diffusibility of body fluids into the absorbent body 1, and enabling quick absorption. . The base material of the cover nonwoven fabric 15 may be any material as long as it has a high diffusion rate and can quickly diffuse body fluids, and for example, a hydrophilic nonwoven fabric, particularly an air-through nonwoven fabric, is preferable.

The longitudinal dimension of the cover nonwoven fabric 15 is, for example, in the range of 100 mm or more and 800 mm or less, or in the range of 150 mm or more and 500 mm or less. Furthermore, the width direction dimension A (FIG. 3) of the cover nonwoven fabric 15 is, for example, in the range of 4 mm or more and 475 mm or less, or in the range of 5 mm or more and 190 mm or less.

The thickness of the cover nonwoven fabric 15 is, for example, in the range of 0.1 mm or more and 3.0 mm or less, and the basis weight thereof is, for example, in the range of 10 g/m ² or more and 60 g/m ² or less, or 15 g/m ² or more and 40 g/m 2 or less. m ² or less. If the thickness is less than 0.1 mm or the basis weight is less than 10 g/m ² or greater than 60 g/m ² , body fluids will not be sufficiently diffused throughout the superabsorbent polymer 12 firmly supported on the base nonwoven fabric 11. Tend. When the thickness is thicker than 3.0 mm, the product tends to be hard and uncomfortable when worn. It is preferable that the cover nonwoven fabric 15 is adhered to the raised surface of the base nonwoven fabric 11 with a hot melt adhesive.

As shown in FIG. 2, the cover nonwoven fabric 15 is arranged along the longitudinal direction. Further, as shown in FIG. 3, the cover nonwoven fabric 15 is arranged at the center of the base nonwoven fabric 11 in the width direction, and the ratio of the widthwise dimension A of the cover nonwoven fabric 15 to the widthwise dimension B of the base nonwoven fabric 11 is, for example, , in the range of 5% or more and 50% or less, or in the range of 8% or more and 47% or less. When the ratio exceeds 50%, the thickness of the absorbent core 1 tends to increase due to the thickness of the cover nonwoven fabric 15. If the ratio is less than 5%, the superabsorbent polymer 12 at the position that receives body fluids swells after absorbing the fluid, gel blocking occurs, and the absorption performance of the absorbent body 1 tends to decrease. Arranging at the center in the width direction means that the center in the width direction of the base nonwoven fabric 11 and the center in the width direction of the cover nonwoven fabric 15 are arranged at substantially the same position in the thickness direction.

(Super absorbent polymer)
The superabsorbent polymer 12 is not particularly limited as long as it can absorb and retain body fluids and prevent backflow, such as polyacrylates, polyaspartates, (starch/acrylic acid) graft copolymers, etc. , (acrylic acid/vinyl alcohol) copolymer, (isobutylene/maleic anhydride) copolymer, and saponified products thereof. The superabsorbent polymer 12 can be used alone or in combination of two or more. Among these, from the viewpoint of absorption per weight, polyacrylates are preferred, and sodium polyacrylate is more preferred. Further, the basis weight of the superabsorbent polymer 12 is, for example, in the range of 150 g/m ² or more and 1000 g/m ² or less in order to ensure the absorption performance required for various absorbent articles. Further, from the viewpoint of further improving absorption performance, texture after absorption, and ease of movement of the wearer, the basis weight of the superabsorbent polymer 12 is, for example, in the range of 300 g/m ² or more and 900 g/m ² or less.

In addition, by avoiding fine powders that have poor fluidity as powder, the basic performance regarding absorption can be improved, and from the viewpoint of reducing the rough texture that occurs due to the hardness of the superabsorbent sheet 10, the superabsorbent The median particle diameter of the polymer 12 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.

It is preferable that the superabsorbent polymer 12 is firmly supported between the fibers of the raised portion of the base nonwoven fabric 11 using a hot melt adhesive. When the basis weight of the base nonwoven fabric 11 is relatively low, the hot melt adhesive functions particularly effectively in order to reinforce the adhesion and support of the superabsorbent polymer 12. In addition, the content of the hot melt adhesive is, for example, in a range of 10 g/m ² or less so as not to inhibit the absorbency of the superabsorbent polymer 12 and not to impair the feel when worn. Hot melt adhesives include synthetic rubbers such as styrene-butadiene-styrene copolymers and styrene-isoprene-styrene copolymers, or ethylene-vinyl acetate copolymers with a melting point of 100°C or higher and 180°C or lower. Olefin-based hot melt adhesives such as the following can be used. 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.

(Highly absorbent sheet)
FIG. 3 is a cross-sectional view in the width direction of the superabsorbent sheet 10 used in the absorbent body 1 of this embodiment. As shown in FIG. 3, the superabsorbent sheet 10 used in the absorbent body 1 includes a base nonwoven fabric 11 whose one side surface is raised, a cover nonwoven fabric 15 that covers a part of the raised surface of the base nonwoven fabric 11, and a raised base nonwoven fabric 11. The superabsorbent polymer 12 is firmly supported between the fibers of the portion. By dispersing and firmly supporting the superabsorbent polymer 12 between the fibers of the raised portion of the base nonwoven fabric 11, body fluids are appropriately diffused or retained in the base nonwoven fabric 11 around the superabsorbent polymer 12, and are absorbed. Performance is improved, and sufficient absorption performance can be ensured even without fluff pulp. Further, as described above, the presence of the cover nonwoven fabric 15 provides the non-existence area 14 of the superabsorbent polymer 12 on the raised surface of the superabsorbent sheet 10 that overlaps the cover nonwoven fabric 15 in the thickness direction. The existence region 14 plays the role of a pseudo slit, and the absorption performance of the superabsorbent sheet 10 and the absorbent body 1 is improved.

(hydrophilic sheet)
As shown in FIGS. 4 and 5, the absorbent body 1 of this embodiment is a hydrophilic sheet that adheres to the raised surface of the superabsorbent sheet 10 (or the base nonwoven fabric 11) and the entire non-skin side surface of the cover nonwoven fabric 15. It has 20. By adhering the raised surface of the superabsorbent sheet 10 to the hydrophilic sheet 20, the superabsorbent polymer 12 is prevented from leaking to the outside of the absorbent body 1, and the feel when worn is further improved. Examples of the hydrophilic sheet 20 include tissue paper, absorbent paper, and hydrophilic nonwoven fabrics such as spunbond nonwoven fabrics and airlaid nonwoven fabrics. Among these, hydrophilic nonwoven fabrics, tissue paper, etc. are preferred from the viewpoint of availability and cost. Further, the basis weight of the hydrophilic sheet 20 is, for example, in the range of 10 g/m ² or more and 60 g/m ² or less, or in the range of 13 g/m ² or more and 50 g/m ^{2 or} less. When adhering the raised surface of the superabsorbent sheet 10 to the hydrophilic sheet 20, it is preferable to fix the superabsorbent sheet 10 and the hydrophilic sheet 20 using a hot melt adhesive or heat embossing.

<Manufacturing method of absorber>
Although the method for manufacturing the absorbent body 1 is not particularly limited, the following method may be mentioned as an example. First, one surface of the base nonwoven fabric 11 is raised using a rotary saw blade or a needle punch. Thereafter, the cover nonwoven fabric 15 is adhered to the raised surface of the base nonwoven fabric 11 using a hot melt adhesive or the like. Next, the superabsorbent polymer 12 is fixedly supported between predetermined fibers of the raised portion of the base nonwoven fabric 11 using a hot melt adhesive or the like. The cover nonwoven fabric 15 provides a region 14 in which the superabsorbent polymer 12 is not present under the cover nonwoven fabric 15, which functions like a slit in the absorbent body 1. Thereafter, the raised side of the base nonwoven fabric 11 and the hydrophilic sheet 20 are adhered with hot melt adhesive or the like, and the base nonwoven fabric 11 is folded in thirds with the non-raised side facing inside and both widthwise ends facing the center. The absorbent body 1 is obtained by stretching the hydrophilic sheet 20 in the width direction so that both ends thereof overlap each other on the top sheet 25 side of the opening of the groove 21.

At this time, in the absorbent body 1 , the surface with the groove 21 opened in the center of the inner third fold of the superabsorbent sheet is the top sheet 25 side of the absorbent article 50 . The folds of the inner three-fold draw a smooth arc as shown in FIG. 4, but they may also draw an angular U-shape as shown in FIG. As described above, the groove portion 21 is formed at the center of the absorbent body 1 by a distance C, and this portion serves as a slit in the absorbent body 1 . Further, it is preferable that the abundance ratio of the superabsorbent polymer 12 in the folded portion 13 of the absorbent core 1 is smaller than the abundance ratio of the superabsorbent polymer 12 in the non-folded portion. At this time, each abundance ratio indicates the ratio of the amount of superabsorbent polymer 12 present in the folded portion 13 or the non-folded portion to the total amount of superabsorbent polymer 12 contained in the absorber 1. The ratio of the abundance ratio of the superabsorbent polymer 12 in the non-folded portion 13 of the absorbent body 1 to the abundance ratio of the superabsorbent polymer 12 in the folded portion is, for example, in the range of 1/99 to 49/51, or 5/99 to 49/51. The range is 95 or more and 40/60 or less. By having more of the superabsorbent polymer 12 in the non-folded portion, the absorption performance of the absorbent body 1 is further improved.

(back seat)
The back sheet 30 may be formed using a liquid-impermeable base material that prevents body fluids held by the absorbent core 1 from wetting clothing, and may be formed using a resin film or a laminated layer of a resin film and a nonwoven fabric. formed from materials such as composite sheets. The manufacturing method of the nonwoven fabric used in the composite sheet is not particularly limited, and examples thereof include spunbond nonwoven fabric, meltblown nonwoven fabric, spunbond nonwoven fabric/meltblown nonwoven fabric, composite nonwoven fabrics in which spunbond nonwoven fabric/meltblown nonwoven fabric/spunbond nonwoven fabric are laminated, and these. Examples include composite materials. Examples of the resin film include polyester, polyvinyl alcohol, polyethylene, polypropylene, and a composite film of polyethylene and polypropylene.

In terms of strength and workability, the basis weight of the backsheet 30 is, for example, in the range of 15 g/m ² or more and 40 g/m ² or less. Further, in order to prevent stuffiness when worn, it is preferable that the back sheet 30 has breathability. In order to provide the backsheet 30 with air permeability, for example, a filler may be added to the base resin film, or the backsheet 30 may be embossed for perforation. In addition, calcium carbonate can be mentioned as a filler, and its compounding method can be carried out by any known method without restriction.

(3D gathers)
In addition, as shown in FIG. 1, the absorbent article 50 is provided with three-dimensional gathers on the top sheet 25 along the longitudinal direction of the absorbent article 50 in order to prevent body fluids excreted by the user from leaking sideways. A pair of three-dimensional gathers 40 having elastic members may be provided. The outer end of the three-dimensional gathers 40 in the width direction of the absorbent article 50 is fixed to the backsheet 30, the inner end is fixed to the topsheet 25, and the center is a free end that is not fixed to the topsheet 25. Three-dimensional gathered sheets are arranged. By providing the elastic member for three-dimensional gathers along the longitudinal direction, the three-dimensional gathers 40 have erectability and can be deformed to match the wearer's body shape.
As the elastic member for the three-dimensional gathers, for example, polyurethane thread, band-shaped polyurethane film, thread-like or band-like natural rubber, etc. are used, and as the three-dimensional gather sheet, a water-repellent or liquid-impermeable material made of hydrophobic fibers is used. Nonwoven fabrics such as spunbond nonwoven fabrics, meltblown nonwoven fabrics, and three-layer laminated composite nonwoven fabrics of spunbond/meltblown/spunbond are used.

<Method for manufacturing absorbent articles>
The method for manufacturing the absorbent article 50 includes sandwiching the absorbent core 1 obtained as described above between the top sheet 25 and the back sheet 30, installing the three-dimensional gathers 40 on the top sheet 25, and It can be manufactured by fixing the sheet 25 and the back sheet 30 partially or over the entire circumference using a hot melt adhesive, heat embossing, ultrasonic embossing, high frequency embossing, or the like. 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, the present invention will be described in detail by giving examples. Note that the present invention is not limited to the examples shown below.

<Production of absorbent body and absorbent article>
First, an air-through nonwoven fabric (basis weight 40 g/m ² , width dimension 100 mm, longitudinal dimension 400 mm) was prepared as a base nonwoven fabric, and one surface of the base nonwoven fabric was physically raised with a rotary saw blade to create a cover nonwoven fabric. (Basic weight: 15 g/m ² , Width dimension: 30 mm, Longitudinal dimension: 400 mm) was adhered to the center of the base nonwoven fabric in the width direction at a distance of 35 mm from both ends of the base nonwoven fabric in the width direction using a hot melt adhesive. Thereafter, a superabsorbent polymer (basis weight 380 g/m ² ) was dispersed on the raised surface of the base nonwoven fabric, and was fixedly supported between the fibers of the raised portion of the base nonwoven fabric using a hot melt adhesive.

Furthermore, a spunbond nonwoven fabric (basis weight 10 g/m ² , width direction dimension 123 mm, longitudinal direction dimension 400 mm) was prepared as a hydrophilic sheet, and the raised side of the base nonwoven fabric and the hydrophilic sheet coated with hot melt adhesive were prepared. A superabsorbent sheet was obtained by adhering the sheets. Next, the superabsorbent sheet is placed so that the non-raised surface of the base nonwoven fabric is on the inside (the raised surface is placed on the bottom side of the base nonwoven fabric), leaving 60 mm in the center, and 20 mm on each side facing the center. The absorbent body of Example 1 was produced by folding the sheets in three directions and fixing the overlapping hydrophilic sheets in the center with a hot melt adhesive.

In Example 2, an air-through nonwoven fabric with widthwise dimensions of 114 mm and longitudinal dimensions of 400mm was used as the base nonwoven fabric, an airthrough nonwoven fabric with widthwise dimensions of 11.4mm and longitudinal dimensions of 400mm was used as the cover nonwoven fabric, and a hydrophilic sheet was used as the hydrophilic sheet. Using spunbond nonwoven fabrics with a width direction dimension of 126 mm and a longitudinal direction dimension of 400 mm, the superabsorbent sheet was fabricated with the exception of leaving 60 mm in the center and folding 27 mm on each side toward the center using an inward trifold. An absorbent body of Example 2 was produced in the same manner as Example 1.

In Example 3, an air-through nonwoven fabric with a width direction dimension of 90 mm and a longitudinal dimension of 400 mm was used as the base nonwoven fabric, an air through nonwoven fabric with a width direction dimension of 45 mm and a longitudinal dimension of 400 mm was used as the cover nonwoven fabric, and a hydrophilic sheet was used in the width direction. Example 1 was performed using spunbond nonwoven fabrics each having a dimension of 140 mm in the longitudinal direction and a dimension in the longitudinal direction of 400 mm, leaving 60 mm in the center of the produced superabsorbent sheet, and folding the left and right 15 mm inward in three toward the center. In the same manner as above, the absorbent body of Example 3 was produced.

In Comparative Example 1, a superabsorbent sheet was produced using a base nonwoven fabric and a hydrophilic sheet having a widthwise dimension of 60 mm and a longitudinal dimension of 400 mm, and was arranged in the same manner as in Example 1, except that it was arranged without being folded. , an absorber of Comparative Example 1 was produced.

In Comparative Example 2, air-through nonwoven fabric (basis weight 20 g/m ² )/super absorbent polymer (basis weight 280 g/m ² )/air through nonwoven fabric (basis weight 20 g/m ² )/super absorbent polymer (basis weight 100 g/m 2 ) The absorbent body of Comparative Example ² was a sheet (all dimensions in the width direction were 60 mm and all dimensions in the longitudinal direction were 400 mm) in which a spunlace nonwoven fabric (basis weight: 20 g/m ² ) was laminated. Note that each of the air-through nonwoven fabrics used in Comparative Example 2 was not subjected to the raising treatment like the base nonwoven fabric used in Example 1.

In Comparative Example 3, a mixture of super absorbent polymer (basis weight 380 g/m ² ) and fluff pulp (basis weight 400 g/m ² ) was covered with tissue paper (16 g/m ² ), and The absorbent body of Comparative Example 3 was made into a substantially rectangular shape with a dimension of 60 mm and a longitudinal dimension of 400 mm.

In Comparative Example 4, a base nonwoven fabric and a hydrophilic sheet each having a widthwise dimension of 60 mm and a longitudinal dimension of 400 mm were used, and a superabsorbent polymer was dispersed with a basis weight of 135 g/m ² to produce a superabsorbent material. An absorbent body of Comparative Example 4 was produced in the same manner as in Example 1, except that a flexible sheet was produced and placed without being folded.

<Measurement items>
Using absorbent articles comprising the absorbent bodies of Examples 1 to 3 and Comparative Examples 1 to 4 obtained above, the following absorption rate, amount of reversion, and thickness of the absorbent body were measured. In addition, the following sensory evaluation was performed. The results are shown in Table 1. The top sheet is made of air-through nonwoven fabric with a basis weight of 25 g/m ² and dimensions of 80 mm x 400 mm x 0.2 mm, and the back sheet is a polyethylene film with a basis weight of 17 g/m ² and dimensions of 80 mm x 400 mm x 0.1 mm. was used.

(absorption rate)
40 ml of 0.9% by mass physiological saline (37°C) was poured into the absorber of each Example and each Comparative Example from a cylinder with an inner diameter of 30 mm while applying a pressure of 46 g/cm ² . The time (seconds) until water was absorbed onto the absorber surface was measured as the first absorption rate. After 3 minutes, 40 ml of 0.9% by mass physiological saline (37°C) was poured again, and the time (seconds) until the physiological saline was absorbed into the absorber surface was measured as the second absorption rate. The smaller the value, the better the absorbency.

(reverse amount)
200 ml of physiological saline was poured into the absorbers of Example 1 and each comparative example, and 10 minutes after the water was poured, a filter paper was pressed onto the surface of the absorber under a load of 35 gf/ ^cm2 , and the filter paper was returned to the surface in 1 minute. The moisture content was measured. The smaller the amount of reversion, the drier the absorber is.

(Thickness of absorber)
The thickness of each of the absorbers of Examples and Comparative Examples was measured when no pressure was applied and when a predetermined pressure (35 g/cm ² in this case) was applied. In addition, the thickness under a load of 35 g/cm ² is determined as the value obtained by subtracting the height of the weight itself at the same predetermined position from the height of the weight at the predetermined position when the weight is placed on the absorbent article. .

(sensory evaluation)
With the cooperation of eight panelists, we evaluated the wearing comfort (fit, softness) and absorbency (absorption A sensory evaluation was conducted with two options: "good" or "bad" regarding the non-leakage of the product and the dryness of the product. The wearer used it for 8 hours and evaluated it in daily activities, and the results are shown in Table 1.
○: When the number of wearers who selected "Good" is 6 or more and 8 or less △: When the number of wearers who selected "Good" is 3 or more and 5 or less ×: The number of wearers who selected "Good" is 1 When there are one or two wearers, or when there is no wearer who selected "Good"

Examples 1 to 3, in which the base nonwoven fabric was folded in thirds with the non-raised side facing inside, had good softness, fit, no leakage to the outside of the absorbent article, and smooth feel. On the other hand, Comparative Example 1, which used only one superabsorbent sheet without a cover nonwoven fabric, was inferior in fit and dryness. Comparative Example 2, in which the base nonwoven fabric and the superabsorbent polymer were laminated, was significantly inferior in softness and fit, and leakage to the outside of the absorbent article also occurred. Comparative Example 3 using fluff pulp was significantly inferior in dry feel. In addition, Comparative Example 4 using a superabsorbent polymer with a small basis weight had poor fit and leakage to the outside of the absorbent article.
As described above, according to the absorbent article of the present invention, it is possible to provide an absorbent body that does not contain fluff pulp and has good absorbency and wear comfort, and an absorbent article that includes the absorbent body.

1 Absorbent body 10 Super absorbent sheet 11 Base nonwoven fabric 12 Super absorbent polymer 13 Folded portion 14 Non-existent area 15 Cover nonwoven fabric 20 Hydrophilic sheet 21 Groove 25 Top sheet 30 Back sheet 40 Three-dimensional gathers 50 Absorbent article

Claims (6)

An absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable backsheet disposed opposite to the topsheet, and an absorbent body disposed between the topsheet and the backsheet. And,
The absorbent body includes a superabsorbent sheet and a hydrophilic sheet,
The superabsorbent sheet is
a base nonwoven fabric having a raised surface and a non-raised surface;
a cover nonwoven fabric that covers a portion of the raised surface of the base nonwoven fabric;
a superabsorbent polymer fixedly supported between the raised fibers of the base nonwoven fabric,
The hydrophilic sheet covers the entire raised surface of the base nonwoven fabric and the non-skin side surface of the cover nonwoven fabric,
The cover nonwoven fabric is
disposed at the center in the width direction of the base nonwoven fabric,
The ratio of the dimension in the width direction to the dimension in the width direction of the base nonwoven fabric is 5% or more and 50% or less,
A region where the superabsorbent polymer is not present is provided on the raised surface of the superabsorbent sheet that overlaps the cover nonwoven fabric in the thickness direction,
The absorber is
It has an inner three-fold shape with the non-raised surface of the base nonwoven fabric facing inside,
a groove having an opening between both end faces in the width direction of the superabsorbent sheet and a bottom surface of the non-raised surface of the base nonwoven fabric facing the top sheet;
Both ends of the hydrophilic sheet in the width direction cover the opening of the groove and overlap in the thickness direction, and the overlapping width is equal to the width of the absorbent body folded in thirds. 5% or more and 50% or less,
The absorber is
In a flat state before folding in three, the thickness measured under a load of 35 g / cm ² is 1.0 mm or more and 4.0 mm or less, and the thickness measured under a load of 35 g / cm ² is An absorbent article having a thickness of 30% or more and 70% or less of the thickness measured under no load. The cover nonwoven fabric is an air-through nonwoven fabric, has a thickness of 0.1 mm or more and 3.0 mm or less, and has a basis weight of 10 g/m ² or more and 60 g/m ² or less. Absorbent articles. The absorbent article according to claim 1 or 2, wherein the abundance ratio of the superabsorbent polymer in the folded portion of the absorbent body is smaller than the abundance ratio of the superabsorbent polymer in the non-folded portion. The base nonwoven fabric is an air-through nonwoven fabric, the basis weight is 20 g/m ² or more and 120 g/m ² or less, the thickness is 0.3 mm or more and 8.0 mm or less, and the thickness of the fibers constituting the base nonwoven fabric is The absorbent article according to any one of claims 1 to 3, wherein the absorbent article is 1.8 dtex or more and 9.0 dtex or less. The absorbent article according to any one of claims 1 to 4, wherein the superabsorbent polymer has a basis weight of 150 g/m ² or more and 1000 g/m ² or less. The absorbent article according to any one of claims 1 to 5, wherein the hydrophilic sheet is a hydrophilic nonwoven fabric or tissue paper with a basis weight of 10 g/m ² or more and 60 g/m ² or less. .