JP7293064B2 - absorbent article - Google Patents

Description

The present invention relates to absorbent articles.

Conventionally, absorbent articles have a problem of permeation performance of loose stools and the like. Specifically, part of loose feces, etc., is not absorbed by the absorbent article and remains on the top sheet, or is not completely permeated through the second sheet interposed between the top sheet and the absorbent body, and is It remains inside to cause clogging, or returns to the top sheet and leaks to the outside, causing skin rashes and complicated wiping operations. In addition, loose stools and the like refer to viscous excrements that contain solids or do not contain solids, such as menstrual blood, vaginal discharge, loose stools, watery stools, diarrheal stools, and the like.

In order to solve such problems, a first layer (fiber layer) containing synthetic fibers containing a water-repellent fiber treatment agent and a second layer (fiber layer) containing fibers having a low degree of water repellency are provided. Sheets for absorbent articles containing such a material have been proposed (see Patent Documents 1 and 2, for example).

This patent document 1 describes that the sheet can transfer excretory fluid such as menstrual blood or urine to the absorbent body. However, loose stools and the like, which are particularly viscous, are absorbed by the sheet, but remain inside the sheet, specifically inside the first nonwoven fabric and the second nonwoven fabric, and may cause clogging.

Japanese Patent No. 6366892 Japanese Patent No. 5112677

Therefore, the main object of the present invention is to improve the permeability of loose feces and the like from the surface to the inside.

The absorbent article that solves the above problems is as follows.
<First Aspect>
A top sheet that permeates loose feces, etc., a second sheet that is adjacent to the outside of the top sheet and permeates loose feces, etc., and an absorbent element arranged on the outside of the second sheet,
The second sheet is a laminated nonwoven fabric composed of an inner layer, an outer layer, and an intermediate layer interposed therebetween,
where r1 is the degree of water repellency of the inner layer, r2 is the degree of water repellency of the intermediate layer, and r3 is the degree of water repellency of the outer layer, satisfying the relationship r2>r1≧r3,
When the gap between fibers in the inner layer is s1, the gap between fibers in the intermediate layer is s2, and the gap between fibers in the outer layer is s3, the relationship s3 < s2 ≤ s1 is satisfied.
An absorbent article characterized by:

(Effect)
In the present absorbent article, excreted loose stools and the like permeate the top sheet and reach the second sheet, and then the loose stools and the like are rapidly transferred from the inner surface layer to the intermediate layer. This is probably because the intermediate layer has a higher degree of water repellency than the inner layer and has lower adhesion to fibers such as loose stools, so loose stools can easily permeate through the fiber layer in the intermediate layer than in the inner layer. It is presumed that this is because of the increased elasticity (they can easily pass through the fibers without adhering to the fibers).

Loose stools and the like transferred to the intermediate layer are then rapidly transferred to the outer surface layer and further transferred to the absorbent element. This is probably because the space between fibers is smaller in the outer layer than in the middle layer, so the density between fibers is higher in the outer layer than in the middle layer, and the migration force is caused by capillary action (fiber density gradient). It is presumed that this is due to the fact that loose stools and the like are easily transferred to the outer layer.

Therefore, in the present absorbent article, the gradient of water repellency promotes the permeation of loose feces from the inner layer to the intermediate layer, and the density gradient of the fibers promotes the permeation of loose feces from the intermediate layer to the outer layer. Loose stools and the like are less likely to stay on the second sheet, and easily permeate from the surface to the inside. For the same reason, loose feces and the like that have passed through the second sheet are less likely to return to the top sheet side.

<Second Aspect>
The outer layer has a fiber fineness of 5 to 6 dtex,
The fiber fineness of the inner layer is within the range of 4 to 6 dtex and is greater than the fineness of the fibers of the outer layer and the intermediate layer,
The fiber fineness of the intermediate layer is within the range of 4 to 6 dtex and is smaller than the fineness of the inner layer fiber,
An absorbent article according to the first aspect.

(Effect)
Since the fineness between the fibers decreases from the inner layer to the outer layer, the density between the fibers increases toward the outer layer. That is, there is a density gradient between fibers. Therefore, loose stools and the like easily move to the outer surface layer side.

In general, when drying a laminated nonwoven fabric consisting of an inner layer, an intermediate layer, and an outer layer with hot air in a drying process in manufacturing, hot air is blown from the inner layer side to the outer layer side with the outer layer facing the conveying surface. When applied, the outer layers become more entangled with each other and have the highest density.

<Third Aspect>
The contact angle of the inner surface layer is 30° to 70°,
The contact angle of the intermediate layer is 1.3 to 2.5 times the contact angle of the inner layer,
The contact angle of the outer surface layer is 0.3 to 1 times the contact angle of the inner surface layer,
An absorbent article according to the first or second aspect.

(Effect)
Since the intermediate layer has the largest contact angle in the laminated nonwoven fabric, the intermediate layer has the strongest water repellency. As a result, loose stools and the like are smoothly transferred from the outer surface layer to the intermediate layer.

<Fourth Aspect>
The laminated nonwoven fabric is obtained by laminating short fibers coated with a water repellent agent in the order of an outer layer, an intermediate layer and an inner layer, and then passing hot air from the inner surface side to the outer surface side to fuse the fibers. An air-through nonwoven fabric with a total basis weight of 15 to 60 g / m ² ,
An absorbent article according to the third aspect.

(Effect)
In such an air-through nonwoven fabric, due to the blowing of hot air and the self-weight of the fibers, the voids between the fibers continuously decrease from the inner surface side to the outer surface side (a density gradient of the fibers is formed), so even in the same layer Capillary action facilitates movement of loose stools outward.

<Fifth Aspect>
The top sheet is provided with a plurality of rows of permeable holes arranged in the front-rear direction at predetermined intervals in the width direction,
an effective opening area of each of the through holes is 10,000 to 50,000 mm ² ;
The permeation hole group is formed in an excretion region including at least a portion of the top sheet facing an excretion portion such as loose stool and its surroundings,
The opening area ratio of the transmission hole group with respect to the top sheet is 20 to 50%,
An absorbent article according to the first aspect.

(Effect)
If loose feces or the like remains on the top sheet, it may cause a skin rash, or the loose feces or the like adheres to the skin, requiring a complicated wiping operation. Therefore, it is important to quickly transfer loose stools and the like to the second sheet through the top sheet. Since the top sheet of the above aspect has permeable hole groups and does not block loose stools, etc., it is possible to quickly permeate loose stools, etc., and transfer them to the second sheet. In addition, when loose stools and the like are transferred to the second seat, it becomes difficult for them to return later.

<Sixth Aspect>
The second sheet has a thickness of 3 to 20 mm,
the intermediate layer is thicker than the inner layer and the outer layer;
An absorbent article according to the first aspect.

(Effect)
In the middle layer imparted with water repellency, loose stools and the like are less likely to adhere to the fibers, so that they are easily transferred from the middle layer to the outer surface layer. If the thickness of the intermediate layer is relatively thin, the ratio of at least one of the thickness of the inner layer and the thickness of the outer layer increases accordingly. Since the inner layer and the outer layer have lower water repellency than the intermediate layer, loose stools and the like adhere to at least one of the inner layer and the outer layer more easily. If it does so, the permeability|transmittance of loose feces etc. in a second sheet will become dull.

However, in this aspect, the thickness of the intermediate layer in the thickness of the second sheet is sufficiently ensured, and the thickness of at least one of the inner layer and the outer layer is relatively thin, so loose stools and the like are prevented from occurring in the inner layer. Alternatively, it becomes difficult to stay in the outer surface layer and easily permeates the second sheet.

As described above, according to the present invention, it is possible to provide an absorbent article sheet through which loose stools and the like can easily pass.

Fig. 2 is a plan view (skin-contacting surface) of the absorbent article in an unfolded state; Fig. 2 is a plan view (non-skin-contacting surface) of the absorbent article in an unfolded state; FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; FIG. 4 is an explanatory diagram of a portion where an absorbent article is fixed; It is explanatory drawing of a contact angle. FIG. 10 is a plan view (skin-contacting surface) of an absorbent article in another form in an unfolded state; FIG. 4 is a view of the fibers forming the inner surface layer and the droplets; FIG. 4 is a drawing of fibers and droplets forming an intermediate layer; FIG. 4 is a view of the fibers and droplets forming the outer surface layer; FIG. 4 is an explanatory diagram showing an operation for measuring the retention amount of pseudo-stool;

Hereinafter, embodiments of the present invention will be described in detail with reference to the use side of pants-type diapers for adults, taking examples of disposable absorbent articles. Needless to say, it can be applied to various absorbent articles such as pants-type diapers and tape-type diapers.

The absorbent article 200 illustrated in FIGS. 1 to 3 includes a top sheet 22 that permeates loose feces and the like and faces the skin, an absorbent element 23 that retains loose feces and the like, and a space between the top sheet 22 and the absorbent element 23. A second sheet 26 intervening between the second sheet 26 that permeates loose feces and the like and covers the inner surface of the absorbent element 23, and an impermeable sheet 21 that is on the non-skin contact side of the absorbent element 23 and covers the outer surface of the absorbent element 23. A back sheet 25 is provided to cover the outer side of the impermeable sheet 21 such as loose stools and serve as a non-skin-contacting surface (outer surface) of the absorbent article 200 . Further, the product has gathered sheets 24, 24 standing on the wearer's side on both sides in the left-right direction. Note that the top sheet 22 may or may not be provided. The dimensions of the absorbent article 200 can be 100-850 mm in the longitudinal direction LD and 50-600 mm in the width direction WD.

(top sheet)
When the top sheet 22 is provided, a known sheet can be used without particular limitation as long as it is a sheet that allows loose feces to pass through. . The top sheet 22 is formed with a large number of through holes H, H, . Here, the excretion area varies depending on the nature of loose stools, etc., but for example, it has a length of 2/3 of the length L of the longitudinal direction LD of the absorbent article 200 and the width of the absorbent element 23. It can also be a region that includes a part that opposes the excretory part such as loose stool.

Although there is no particular limitation on the form of arrangement of the transmission holes in the top sheet 22, it can be arranged as follows. For example, a plurality of rows of transmission holes arranged in the front-rear direction at predetermined intervals may be provided in the width direction (which may be oblique or width directions). Regarding the arrangement of the transmission holes, specifically, the transmission holes are arranged in a grid point pattern, an orthorhombic lattice pattern, a honeycomb structure (a structure in which hexagons are arranged without gaps), and a structure in which triangles are arranged without gaps. It can be arranged in the shape of each intersection.

As for the group of through holes H, H..., the effective opening area of each through hole is 10,000 to 50,000 mm ² , more preferably 15,000 to 45,000 mm ² , and the opening area ratio is 20 to 50. %, more preferably 25-45% are preferably used. If the opening area and the opening area ratio are smaller than this range, viscous loose stools and the like will have poor permeability. It becomes difficult to feel the texture and good tactile sensation of If the open area ratio is excessively large, the strength of the top sheet 22 is unfavorably low.

When the top sheet 22 is provided, the top sheet 22 may or may not be fixed to the gather sheet 24, the impermeable sheet 21 for loose feces, etc., and the back sheet 25. The topsheet 22 may be secured in some form to the member of the product. In the embodiment, the top sheet 22 is fixed to the second sheet 26. As shown in FIG. For this fixation, the top sheet 22 is usually fixed to the second sheet 26 by spirally applying a hot-melt adhesive. However, the top sheet 22 in this embodiment is a perforated sheet with large openings. As a result, the hot-melt adhesive protrudes from the permeation holes to the side of the skin contacting side, and the presence of the hot-melt adhesive inhibits the permeation of loose stools and the like through the permeation holes H. No (if the fixing points are widely dispersed, the top sheet 22 may become loose, and the separation between the two may cause loose stools, etc., to not be smoothly transferred to the second sheet 26). ) range, in order to reduce the total fixing area as much as possible and to prevent the hot melt adhesive from protruding from the transmission hole to the skin contact side, heat sealing or ultrasonic sealing is partially applied. It is desirable to fix the top sheet 22 to the second sheet 26 immediately.

The material of the top sheet 22 is desirably a non-woven fabric in order to improve the feeling on the skin, but a plastic sheet may also be used. The topsheet 22 is permeable to loose feces and the like, and may be perforated or non-perforated. In the case of perforations, the shape of the opening of the transmission hole H may be circular as shown in the drawing, or may be an elliptical, round, triangular, quadrangular, rhomboidal, hexagonal, or other shape having a major axis along the longitudinal direction. They can be arranged in multiples, either regularly or irregularly, over part or all of the topsheet 22 . The raw material fibers of the nonwoven top sheet 22 are not particularly limited. Examples include synthetic fibers such as olefins such as polyethylene and polypropylene, polyesters and polyamides, regenerated fibers such as rayon and cupra, and mixed fibers and composite fibers in which two or more of these are used. can. Further, the nonwoven topsheet 22 may be manufactured by any process. Examples of processing methods include known methods such as spunlace, spunbond, thermal bond, meltblown, needle punch, air through, and point bond methods. For example, if flexibility and drapeability are desired, the spunlace method is preferable, and if bulkiness and softness are desired, the thermal bond method is the preferable processing method. When a non-woven fabric is used for the top sheet 22, the fineness of the fibers constituting the non-woven fabric is preferably 4.0 to 6.0 dtex from the viewpoint of maintaining a space for absorbing loose stools and increasing permeability. Moreover, the basis weight is preferably 30 to 60 g/m ² . Furthermore, the topsheet 22 preferably uses water-repellent or hydrophobic fibers to suppress diffusion on the topsheet 22 .

(second seat)
The second sheet 26 functions to diffuse excreted loose stools, etc., guide them to the absorbent element 23, and prevent loose stools, etc. reaching the absorbent element 23 from returning to the skin side. Characteristically, the second sheet 26 consists of an inner layer, an outer layer, and an intermediate layer interposed between these nonwoven fabrics, and is composed of three layers of nonwoven fabrics. The second sheet 26 is arranged in the absorbent article 200 such that the inner layer of the three-layer laminated nonwoven fabric constituting the second sheet 26 is on the skin-contacting side and the outer layer is on the non-skin-contacting side. . That is, the outer surface layer forming the outer surface of the second sheet 26 covers the absorbent element 23 .

Excreted loose feces and the like are first absorbed by the inner surface layer of the second sheet 26 , pass through the intermediate layer and the outer surface layer in order, and are absorbed by the absorbent element 23 .

The voids between the fibers of the laminated nonwoven fabric have a relationship of s3 < s2 ≤ s1, where s1 is the void between the fibers in the inner layer, s2 is the void between the fibers in the intermediate layer, and s3 is the void between the fibers in the outer layer. A form that satisfies is preferred. Furthermore, when s2<s1, the moving force of loose feces and the like due to capillary action increases from the outer surface to the inner surface. It is preferable that the space between the fibers is shorter, for example, in the outer layer than in the inner layer and the intermediate layer, and it is particularly preferable that the intermediate layer is shorter than the inner layer. Further, for example, the inner layer should be 800 μm or more and 1000 μm or less, the intermediate layer should be 600 μm or more and 800 μm or less, and the outer layer should be 200 μm or more and 600 μm or less. If the inner layer and the intermediate layer are smaller than this range, the shape of the nonwoven fabric tends to collapse due to movement of the wearer or the like. If the inner layer and intermediate layer are larger than this range, the difference in density from the outer layer will be negligible. In this case, not only loose stools and the like do not smoothly move from the inner surface layer to the outer surface layer, but also loose stools and the like may return. If the outer surface layer is larger than this range, the difference in density between the inner surface layer and the intermediate layer becomes very small, causing the above problems. If it is smaller than this range, a large amount of loose stool or the like is retained by the outer surface layer, and is difficult to transfer to the absorbent element 23 .

In order to impart water repellency to the non-woven fabric constituting the second sheet 26, there is no particular limitation, and any suitable known technique can be employed. For example, a method of adhering a water repellent that imparts water repellency to the surface of the fibers of the nonwoven fabric or dispersing it between the fibers is preferable. Methods of attachment include coating on fibers, spraying onto fibers, and spinning of resin containing a water repellent agent.

Examples of the water repellent include known chemical compounds. For example, drugs containing metal salts of alkyl phosphates having an alkyl group of 14 or more carbon atoms or their ammonium salts, drugs containing perfluoroalkyl carboxylates, perfluoroalkyltrimethylammonium salts, perfluoroalkyl-containing oligomers, fluorine-containing vinyl A drug containing a monomer polymer, a drug containing polydimethylcycloxane, an amino-modified silicone, a silicone surfactant, and a drug containing an alkylketene dimer are preferred.

In the present embodiment, the inner layer and the outer layer have lower water repellency than the intermediate layer, and the concept of low water repellency may include hydrophilicity.

In order to impart hydrophilicity to the non-woven fabric, there are no particular restrictions, and known methods can be used as appropriate. For example, a method of attaching a hydrophilicity-imparting agent that imparts hydrophilicity to the fiber surface of the nonwoven fabric or dispersing it between fibers is preferable. Methods of adhesion include coating on fibers, spraying onto fibers, and spinning of resin containing a hydrophilicity-imparting agent.

Hydrophilicity-imparting agents include known chemical compounds, particularly surfactants. For example, surfactants having an alkyl group having 6 or more carbon atoms are preferred, and alkyl ester phosphate salts, dialkyl sulfosuccinate salts, and alkyl sulfonate salts can be exemplified as anionic surfactants. The salt is not particularly limited, and alkali metal salts and alkaline earth metal salts are suitable.

In addition, hydrophilicity imparting agents including dialkyldimethylammonium halides, alkenyldimethylammonium halides, alkylpyridinium halides, and alkenylpyridinium halides may be used. In this case, the number of carbon atoms is desirably 6 or more. The halide may be chlorine, bromine, or the like. Furthermore, betaine-type amphoteric surfactants, amino acid-type amphoteric surfactants, polyhydric alcohol fatty acid esters represented by glycerin fatty acid esters, and hydrophilicity-imparting agents including amino-modified silicones can be mentioned.

The degree of water repellency can be determined by water droplets adhering to the fibers forming the laminated nonwoven fabric. Specifically, the contact angle can be used as an index of water repellency. The contact angle can be measured by the method described in paragraphs [0017] to [0020] of Patent Document 1. That is, the contact angle is the angle formed between the water surface and the fiber surface (the angle within the water) at the point where the free surface of the water contacts the fiber. If the contact angle of the fibers is too small, the liquid backflow prevention property of the nonwoven fabric is lowered. A contact angle can be measured by the following method. For example, a known microscope is fixed in a state in which a measurement section with a lens attached is tilted horizontally. A microscope VHX-1000 manufactured by KEYENCE CORPORATION can be used as a microscope, and a zoom lens VH-Z100R manufactured by KEYENCE CORPORATION can be used as a lens. The nonwoven fabric is cut into a size of 50 mm in the LD direction and 10 mm in the WD direction, and this is used as a measurement sample. As the measurement samples, the inner surface layer portion, the intermediate layer portion, and the outer surface layer portion of the second sheet 26 were cut out. However, for example, measurement samples may be cut from each of the inner surface layer, the intermediate layer, and the outer surface layer at a stage before manufacturing the second sheet 26 . The measurement surface of the measurement sample faces upward and is fixed on a laboratory table, and the measuring instrument is installed so that the WD direction of the measurement sample is perpendicular to the lens surface. Here, the measuring part of the measuring machine is fixed horizontally. By doing so, the observation direction and the WD direction match. Also, most of the fibers are oriented in a direction perpendicular to the observation direction. However, depending on the type of fibers forming the nonwoven fabric, the angle formed by the observation direction and the WD direction may be adjusted to an acute angle or an obtuse angle.

Spray water on the measurement sample. At this time, it is preferable to spray the water in the form of droplets that are as uniform as possible. For uniform droplets, for example, a spray or atomizer can be used. Well-known water such as pure water and ion-exchanged water can be appropriately used as water. Immediately after spraying, an image of the droplet adhering to the fiber is taken with a measuring device. The imaging is repeated in this procedure, and 20 or more images in which the fibers are horizontally oriented are selected from the captured images. Select 10 of the selected images that clearly show fibers and droplets. The measurement of the contact angle α is performed as follows when explained with reference to FIG. One of the points where the air-liquid boundary surface of the droplet 60 and the fiber 70 intersect is set as a reference point α ₀ , and the straight line passing through the reference point α ₀ which is a tangent to the air-liquid interface is the most fiber 70 The angle formed by the orientation direction Q of the fibers 70 and the angle P having a large upward angle with respect to the contact angle α is defined as α. The contact angle α was obtained by selecting a point where the droplet contacts the fiber, drawing a tangent line to the droplet, and determining the angle between the tangent line and the fiber. This contact angle α is measured with a protractor or other known goniometer (image analysis software, etc.).

The contact angle may be measured by taking out fibers constituting the inner surface layer, fibers constituting the intermediate layer, and fibers constituting the outer surface layer from the second sheet, or measuring the inner surface side, the outer surface side, and the intermediate portion of the second sheet. may be measured. In order to measure the contact angle of the middle part, ie the middle layer, the following should be done.

For example, the second seat 26 is ground from the outer surface side with a file or the like. The outer surface side of the second sheet 26 is composed of an outer surface layer, and the intermediate layer is exposed by scraping the outer surface layer. Since the outer layer and the intermediate layer have different densities, it is easy to tell whether the intermediate layer is exposed or not.

Moreover, as a method of not scraping with a file or the like, a method of peeling off the inner surface layer or the outer surface layer of the second sheet 26 may be used. Since the fineness of the inner or outer layer differs from that of the intermediate layer, the degree of entanglement between fibers differs between the inner or outer layer and the intermediate layer. Peeling off the outer layer easily exposes the intermediate layer.

Particular attention should be paid to the following when measuring contact angles: First, the contact angle of a droplet resting on top of the fiber is measured. The contact angle is not measured for droplets that hang down along the fiber and for droplets that span two or more fibers. Secondly, for fibers with fine crimps such as spirals, the measurement is performed at locations where there are few crimps or by stretching the fibers. Thirdly, the measurement result of the contact angle is obtained by changing the measurement point or the measurement sample, selecting 20 or more images in which the fiber is horizontal, and averaging the measurement values. If the fiber is highly hydrophilized, the droplet may move on the fiber when measuring the contact angle. In this case, the measurement is performed after confirming that the droplet has stopped. 30 of the total number of measurements (the total number of measurement points where the droplet was attempted to be photographed, the total number of cases where the droplet moved and did not move during photographing) until the contact angle was measured at 20 points. %, select 10 or more images in which the fiber is horizontal and simply average the measured values to determine the contact angle. If the droplet moves 70% or more of the total number of measurements before the contact angle is measured at 10 points, the contact angle shall be 10° or less.

7 to 9 are images of fibers and droplets, and each figure shows a large number of fibers and droplets, of which representative fibers 70 and droplets 60 are depicted by solid lines.

The images chosen for measuring contact angles are droplets deposited on horizontally oriented fibers (ie, preferably vertically). If the droplet is not on the fiber, such as when the fiber is not oriented horizontally, for example, on the side or below the fiber, the shape of the droplet will be different. If it does so, there exists a possibility that a contact angle may not be able to be measured appropriately.

A preferred embodiment satisfies the relationship r2>r1≧r3, where r1 is the degree of water repellency of the inner layer, r2 is the degree of water repellency of the intermediate layer, and r3 is the degree of water repellency of the outer layer. In particular, the form in which r1>r3 is preferable, and the liquid droplets in the intermediate layer easily move to the inner surface layer, and are less likely to return.

It is preferable that the intermediate layer contains fibers imparted with water repellency, and that each of the inner layer and the outer layer has lower water repellency than the intermediate layer. Water repellency can be evaluated, for example, by a contact angle. For example, the contact angle of the inner layer is 30° to 70°, the contact angle of the intermediate layer is 1.3 to 2.5 times the contact angle of the inner layer, and the contact angle of the outer layer is that of the inner layer. It can be in the form of a layer with a contact angle of 0.3 to 1 times. Moreover, the following form may be sufficient. That is, the contact angle α described above is desirably 70° to 170°, more preferably 100° to 150°, for the fibers forming the intermediate layer. The larger the contact angle α, the higher the water repellency, which is preferable. However, it is difficult to produce a fiber having a contact angle exceeding this range. If it is less than this range, the difference in water repellency between the intermediate layer and the inner and outer layers is small. be.

The contact angle α is preferably 30° to 70° for the fibers forming the inner layer, and 10° to 40° for the fibers forming the outer layer. If the thickness is larger than this range, the difference in water repellency between the inner and outer layers and the intermediate layer is too small, as described above. If it is less than this range, the nonwoven fabric can be said to be hydrophilic, and particularly viscous loose stools and the like may stay in the inner layer and outer layer and may not reach the absorbent element.

Examples of the second sheet 26 include materials similar to those of the top sheet 22 , spunlace nonwoven fabrics, spunbond nonwoven fabrics, SMS nonwoven fabrics, pulp nonwoven fabrics, mixed sheets of pulp and rayon, point bond nonwoven fabrics, and crepe paper. In particular, an air-through nonwoven fabric is preferred because it is bulky.

Synthetic fibers can be used as fibers of the nonwoven fabric forming the second sheet 26 . Synthetic fibers used are not particularly limited, but polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate, polypropylene, polyethylene, polybutene, propylene copolymer, ethylene-vinyl acetate copolymer. Examples include polymers, nylon 6, nylon 12, nylon 66, acrylic resins, polycarbonate, polyacetal, polystyrene, and engineering plastics.

A single fiber made of one or more resins selected from the above can be used as the synthetic fiber. The use of single fibers is less prone to fibrillation and fines due to interfacial delamination between components.

Moreover, the synthetic fiber may be a composite fiber composed of a plurality of components. In the synthetic fiber, each component may consist of one resin, or may consist of a mixture of a plurality of resins. As the conjugate fiber, for example, a core-sheath type, a sea-island type, a split type, or a side-by-side type conjugate fiber can be used.

It is preferable that the fibers forming the inner layer, the fibers forming the intermediate layer, and the fibers forming the outer layer have the same composition. For example, a form in which a nonwoven fabric is formed from one or a plurality of fibers selected from the above can be mentioned. Specifically, as the composition of the fibers forming each of the inner layer, the intermediate layer, and the outer layer, a core-sheath type composite resin in which the resin used for the core is polypropylene, or a mixture of polypropylene resin and polyethylene terephthalate resin is used. It is also possible to use a resin such as However, it is not limited to this specific example.

The total basis weight of the second sheet 26 should be 15-60 g/m ² , preferably 30-50 g/m ² . Below this range, there is a risk that loose stools and the like may return, and above this range, it becomes difficult for loose stools and the like to move smoothly on the second seat 26 . In addition, with regard to the basis weight of each layer, it is preferable that the outer layer is larger than the inner layer and the intermediate layer, and it is particularly preferable that the intermediate layer is larger than the inner layer. Further, it is preferable that the basis weight of the outer layer is 10 to 15 g/m ² , the intermediate layer is 5 to 10 g/m ² , and the inner layer is 15 to 25 g/m ² . If the weight per unit area is less than this range, loose stool held in the absorbent element 23 may move back toward the skin when the body pressure of the wearer is applied to the absorbent article 200 . On the other hand, if the basis weight exceeds this range, loose stools and the like may not be smoothly absorbed into the absorbent element 23 .

As for the fineness of the fibers of the second sheet 26, the outer surface layer is preferably made larger than the inner surface layer and the intermediate layer. Further, it is preferable that the intermediate layer has a smaller fiber fineness than the inner layer. Specifically, the outer layer should be 5.0 to 6.0 dtex, more preferably 5.5 to 6.0 dtex. Further, it is desirable that the inner layer has a thickness of 4.0 to 6.0 dtex, more preferably 4.5 to 5.0 dtex, and the intermediate layer has a thickness of 4 to 6 dtex, more preferably 5.0 to 5.5 dtex. It is preferable that the outer layer has a relatively small fineness so that the absorbent element 23 can quickly absorb loose feces and the like transferred from the inner layer. If the fineness is smaller than this range, the strength of the second sheet 26 is too weak.

The thickness of the second sheet 26 is preferably 3-20 mm, preferably 5-15 mm. Moreover, it is preferable that the intermediate layer is thicker than the inner layer and the outer layer. For example, it is preferable that the ratio of the thickness of the nonwoven fabric is intermediate layer thickness:inner layer thickness:outer layer thickness=1:6:3 to 1:8:1. If the thickness is within this range, reversion such as loose stools is less likely to occur. Note that the thickness can be determined by setting the manufacturing apparatus at the time of manufacture.

In the illustrated example, the absorbent element 23 is protruded in the LD direction and the MD direction and covered with the second sheet 26 . However, the configuration is not limited to this configuration, and a configuration in which the second sheet 26 covers an area smaller than the absorbent element 23 may be employed. For example, the second sheet 26 covers 80% of the absorbent element 23 in the LD direction and 90% of the absorbent element 23 in the MD direction, and the central portion of the second sheet 26 is arranged to face the excretion position for loose stools and the like. can be shaped. In addition, although the excretion position of loose stools is not particularly limited, for example, it can be the middle region of the regions obtained by dividing the absorbent element 23 into three equal parts in the LD direction. Also, the central portion of the second sheet 26 is not particularly limited, but can be, for example, the central area of the areas obtained by dividing the second sheet 26 into three equal parts in the LD direction.

The second sheet 26 having a characteristic structure as in the present invention, that is, the second sheet 26 made of three layers of nonwoven fabric can be produced, for example, by the following method.

First, raw cotton (raw material and The same applies hereinafter).

In addition, through the processes of raw material input, heating, melting, and extrusion, raw cotton (inner layer), which is the raw material of the layer located on the skin contact side, and raw material of the layer (outer layer) located on the non-skin contact side. to produce raw cotton. At this time, when imparting water repellency or hydrophilicity lower than the water repellency imparted to the intermediate layer, a step of imparting water repellency or imparting hydrophilicity is inserted after the raw material is extruded and cooled. It is good to manufacture the raw cotton. Low water repellency can be imparted to fibers by applying a low-concentration water repellent agent, spraying for a short period of time, or the like.

Then, a plurality of lines of the nonwoven fabric manufacturing apparatus (for example, when manufacturing the second sheet 26 with a three-layer structure, a line for manufacturing the inner layer, a line for manufacturing the intermediate layer, and a line for manufacturing the outer layer). There are three lines.), the raw cotton that is the raw material of the inner layer, the raw cotton that is the raw material of the intermediate layer, and the raw cotton that is the raw material of the outer layer are supplied separately. After that, each line separately performs primary defibration, weighing and blending, secondary defibration, tuft formation (the secondary defibrated raw cotton is evenly stored in a box), and web forming (using a card machine). , forming the raw cotton stored in the box into a sheet). Then, each sheet produced by web forming is superimposed and laminated into a plurality of layers, for example, hot air is passed through from the inner surface to the outer surface to bond the fibers, and then foreign matter is mixed. Manufactured through the process of inspection and winding.

Although the above description exemplifies a method of manufacturing a multi-layered nonwoven fabric using the air-through manufacturing method, it is possible to manufacture in the same manner using other manufacturing methods in which the method of fusing the nonwoven fabric is different. Other manufacturing methods include the spunlace method, spunbond method, thermal bond method, meltblown method, needle punch method, point bond method, and the like.

(absorbing element)
The absorbent element 23 is a portion that absorbs and retains loose feces and the like. The absorbent element 23 that directly faces the second sheet 26 and holds loose stools may be an absorbent body, or may be in a form in which the entire absorbent body is wrapped with a packaging sheet.

The absorber can be formed by an aggregate of fibers. The filament assembly may be a filament assembly obtained by laminating short fibers such as cotton pulp or synthetic fibers, or by opening tows (fiber bundles) of synthetic fibers such as cellulose acetate as necessary. can also be used. The fiber basis weight of the absorbent body can be, for example, about 50 to 400 g/m ² when piling up cotton pulp or short fibers, and about 10 to 100 g/m ² for filament aggregates. can be The fineness of synthetic fibers is, for example, 1.0 to 6.0 dtex, preferably 1.2 to 6.0 dtex, more preferably 2.2 to 5.6 dtex. In the case of a filament assembly, the filaments may be non-crimped fibers, but crimped fibers are preferred. The degree of crimping of the crimped fibers can be, for example, about 3 to 30, preferably 5 to 25, more preferably 10 to 20 per 2.54 cm. Further, uniformly crimped crimped fibers can be used.

(superabsorbent polymer particles)
The absorbent body may contain superabsorbent polymer particles in part or in its entirety. Superabsorbent polymer particles include "powder" in addition to "particles". As the superabsorbent polymer particles, those used in this type of absorbent article can be used as they are. Although the particle size of the superabsorbent polymer particles is not particularly limited, for example, sieving using a 500 μm standard sieve (JIS Z8801-1: 2006) (shaking for 5 minutes), and particles falling under the sieve in this sieving When sieving (shaking for 5 minutes) using a 180 μm standard sieve (JIS Z8801-1: 2006), the percentage of particles remaining on the 500 μm standard sieve is 30% by weight or less, and the 180 μm standard sieve It is desirable that the proportion of particles remaining on the top is 60% by weight or more.

Materials for the superabsorbent polymer particles are not particularly limited, but those having a water absorption of 42 g/g or more are suitable. Superabsorbent polymer particles include starch-based, cellulose-based, and synthetic polymer-based particles. and acrylic acid (salt) polymers can be used. As for the shape of the superabsorbent polymer particles, the powder particles that are commonly used are suitable, but other shapes can also be used.

As the superabsorbent polymer particles, those having a water absorption rate of 70 seconds or less, particularly 50 seconds or less are preferably used. If the water absorption rate is too slow, so-called reversion, in which the liquid supplied into the absorbent body returns to the outside of the absorbent body, tends to occur.

As the superabsorbent polymer particles, those having a gel strength of 5 Pa or more are preferably used. As a result, even when the absorbent body is bulky, it is possible to effectively suppress the feeling of stickiness after liquid absorption.

The basis weight of the superabsorbent polymer particles can be appropriately determined according to the absorption amount required for the use of the absorbent. Therefore, although it cannot be generalized, it can be 50 to 500 g/m ² . If the basis weight of the polymer is less than 30 g/m ² , it becomes difficult to secure the absorption capacity. If it exceeds 600 g/m ² , not only the effect is saturated, but also the excessive amount of superabsorbent polymer particles gives a gritty feeling of discomfort.

(packaging sheet)
In order to prevent the superabsorbent polymer particles from slipping out or to enhance the shape retention of the absorbent body, the absorbent body can be incorporated as an absorbent element 23 wrapped in a wrapping sheet. As the packaging sheet, tissue paper, particularly crepe paper, nonwoven fabric, poly-laminated nonwoven fabric, perforated sheet, and the like can be used. However, it is desirable that the sheet is such that the superabsorbent polymer particles do not escape. When non-woven fabric is used instead of crepe paper, hydrophilic SMMS (spunbond/meltblown/meltblown/spunbond) nonwoven fabric is particularly suitable, and polypropylene, polyethylene/polypropylene, etc. can be used as the material. Needless to say, the packaging sheet is made of a material that allows soft stools and the like to permeate.

This packaging sheet may have a structure in which a single sheet wraps the entire absorbent body, or a plurality of sheets, such as two upper and lower sheets, may wrap the entire absorbent body. The wrapping sheet can also be omitted.

The basis weight of the packaging sheet is preferably 11.0 g/m ² or more, more preferably 13.5 g/m ² or more. By setting it to this range, it is possible to prevent loose stools and the like held by the absorbent body from returning and adhering to the wearer's skin, thereby causing a burden on the skin.

The loose stool impermeable sheet 21 arranged on the outer surface of the absorbent element 23 is made of , for example, a plastic sheet. The backsheet may be breathable. The backsheet extends laterally outwardly from the side edges of the absorbent element 23 .

(liquid-impermeable sheet)
The sheet 21 impermeable to loose feces, etc. arranged on the outer surface of the absorbent element 23 is not particularly limited, but preferably has air permeability and moisture permeability. As the impermeable sheet 21 for loose stools, for example, an inorganic filler is kneaded in an olefin resin such as polyethylene or polypropylene, the sheet is molded, and then the sheet is stretched in a uniaxial or biaxial direction. A flexible sheet can be preferably used. As the impermeable sheet 21 for soft stools, etc., a non-woven fabric as a base material with improved waterproofness can also be used.

It is desirable that the sheet 21 impermeable to loose feces and the like extends in the same or wider range than the absorbent element 23 in the front-rear direction LD and the width direction WD. , it is also possible to adopt a structure in which the end portions of the absorbing element 23 are not covered in the front-rear direction LD and the width direction WD.

(back seat)
The back sheet 25 covers the entire back side of the impermeable sheet 21 for soft feces, etc., and gives the outer surface of the product a cloth-like appearance. The back sheet 25 is not particularly limited, and the material fibers include, for example, olefin-based, polyester-based, and polyamide-based synthetic fibers such as polyethylene or polypropylene, regenerated fibers such as rayon and cupra, and natural fibers such as cotton. A spunlace method, a spunbond method, a thermal bond method, an air through method, a needle punch method, or the like can be used as a processing method. However, spunbond nonwoven fabrics, SMS nonwoven fabrics, SMMS nonwoven fabrics, and other long-fiber nonwoven fabrics are suitable because they can achieve both good texture and strength. The non-woven fabric can be used singly or in multiple layers. In the latter case, it is preferable to bond the nonwoven fabrics together with a hot-melt adhesive or the like. When non-woven fabric is used, its fiber basis weight is preferably 9-18 g/m ² , particularly 11-15 g/m ² . The back sheet 25 may not be provided, and in this case, the outer surface of the product is covered with the impermeable sheet 21 for loose stools and the like.

The absorbent article 200 is assumed to be used by being spread or attached to a portion 90 facing the excretory part on the inner surface of the outer 100 such as a disposable diaper or cloth underwear. A non-slip portion 30 is provided on the outer surface of the back sheet 25, ie, the outer surface of the product, so that the absorbent article 200 does not slip or come off from this portion 90 when worn. The anti-slip portion 30 can be formed of, for example, an adhesive layer or hook tape. The hook tape has a large number of hook-shaped projections, and is preferably attached to the anti-slip portion 30 with a hot-melt adhesive or the like. The shapes of the hook-shaped projections include mushroom-shaped, hook-shaped, L-shaped, J-shaped, T-shaped, and double J-shaped (a shape in which J-shaped ones are joined back to back or an anchor-shaped one). etc. can be used.

In the embodiment, the anti-slip portion 30 is provided in a rectangular shape at each of the front end portion FR and the rear end portion BA of the outer surface of the backsheet in the front-rear direction LD . It may be provided continuously over the portion BA . However, as long as the absorbent article 200 does not shift or come off, it is not limited to these.

In the absorbent article 200 without the back sheet 25, the anti-slip portion 30 is preferably provided on the outer surface of the impermeable sheet 21 for loose feces and the like. As for the position to be provided, as in the case of the outer surface of the back sheet, the anti-slip portion 30 is provided in a rectangular shape at each of the front end portion FR and the rear end portion BA in the front-rear direction LD of the outer surface of the impermeable sheet such as loose feces. It may be provided continuously from the front end portion FR to the rear end portion BA of the outer surface of the permeable sheet in the front-rear direction LD.

At both ends of the absorbent article 200 in the front-rear direction, the sheet 21 impermeable to soft feces and the like and the second sheet 26 are attached so as to extend to both front and rear sides from the front and back ends of the absorbent element 23, forming end flaps where the absorbent element 23 does not exist. Part EF is formed.

On both sides of the pad-type absorbent article 200, the sheets 21 impermeable to loose feces and the like extend outside the side edges of the absorbent element 23, and the inner surface of the portion from this extension to the side of the second sheet 26 A widthwise outer portion 24x of the gather sheet 24 is attached to the side flap portion SF along the entire front-rear direction to form a side flap portion SF in which the absorbent element 23 does not exist. The parts where the materials are attached together, including these, can be formed by hot-melt adhesive, heat sealing, or ultrasonic sealing, and are indicated by a hatched pattern in the plan view and a dot pattern in the cross-sectional view. The absorbent element- interposed portion other than the end flap portion EF and the side flap portion SF constitutes the main body portion BD that retains excrement. As the material of the gather sheet 24, a plastic sheet or a meltblown nonwoven fabric can be used, but nonwoven fabric treated with water-repellent silicone or the like is preferably used in terms of feel to the skin.

A widthwise central portion 24c of the gather sheet 24 extends onto the second sheet 26, and an elongated elastic member 24G is attached to the end portion of the widthwise central side in a stretched state along the front-rear direction. It is fixed with a melt adhesive or the like. The elongated elastic member 24G may be made of thread-like, cord-like, belt-like, or the like styrene-based rubber, olefin-based rubber, urethane-based rubber, ester-based rubber, polyurethane, polyethylene, polystyrene, styrene-butadiene, silicon, polyester, or the like. , commonly used materials can be used.

Both gather sheets 24, 24 are fixed by being bonded to the inner surface of the article (the surface of the second sheet 26 and the inner surface of the impermeable sheet 21 such as soft feces in the illustrated embodiment) over the entire front-rear direction at the widthwise outer portion 24x, and the widthwise direction The central portion 24c is bonded and fixed to the inner surface of the article (the surface of the second sheet 26 in the illustrated embodiment) at both ends in the front-rear direction, and is fixed to the inner surface of the article (i.e., the central portion) between the ends in the front-rear direction (i.e., the central portion). In the form, it is not fixed to the second seat 26 surface). This non-fixed portion is a portion that forms a three-dimensional gather that can stand up against the inner surface of the article (the surface of the top sheet 22 in the illustrated embodiment). is located on the boundary with the portion 24c of the .

<Measurement of contact angle>
The contact angles of the fibers forming the inner surface layer, the fibers forming the intermediate layer, and the fibers forming the outer surface layer were measured by the measurement method described above. Of the second sheet 26, the fibers on the inner surface are "fibers forming the inner layer", the fibers on the outer surface are "fibers forming the outer layer", and the fibers in the intermediate portion exposed by peeling off the outer layer are "forming the intermediate layer". fiber. In principle, the contact angle was measured by the method described in paragraphs [0017] to [0020] of Patent Document 1.
(1) Images of the fibers forming the inner surface layer were taken, and five clear images were selected as Test Examples 1 to 5.
(2) Images of the fibers forming the intermediate layer were taken in the same manner as in (1) above, and 5 clear images were selected as test examples 6 to 10. Also, the fibers forming the outer surface layer were imaged, and five clear images were selected as Test Examples 11 to 15.
(3) Table 1 shows the contact angle results for the fibers forming the inner layer, Table 2 shows the contact angle results for the intermediate layer forming fibers, and Table 2 shows the contact angle results for the outer layer forming fibers. Table 3 shows.

<Measurement of retention amount of pseudostool>
(Preparation of pseudo-feces)
In the measurement of the amount of simulated feces retained, the mass of simulated feces retained on the second sheet 26 was measured by the following method. The simulated stool used for the measurement was prepared as follows. Since artificial urine is used when preparing pseudo-stool, the preparation method for artificial urine will be described first.

Artificial urine was prepared as follows. 1418 g of ion-exchanged water was placed in a 3000 ml beaker, and 400 g of urea, 160 g of sodium chloride, 6 g of calcium chloride and 16 g of magnesium sulfate were added while being dissolved to homogenize the concentration to obtain artificial urine.

(1) 270 g of glycerin and 30 g of sodium carboxymethylcellulose (CMC) were placed in a 1000 ml glass beaker and stirred for 10 minutes. At this time, stirring was started after the CMC was sufficiently submerged in the glycerin.
(2) 1540 g of artificial urine was placed in a 3000 ml glass beaker.
(3) To the above (2), 2 g of a surfactant (Neupor) and 260 g of the stirred solution of the above (1) were added and stirred for 1 hour or longer.
(4) 100 g of buckwheat flour and 100 g of this powder were added to the solution after the stirring in (3) above, and the mixture was stirred for 1 hour or more to homogenize the concentration to obtain pseudo feces.

(measurement operation)
(1) Two laminated hard flat plates (first laminated hard flat plate 81, second laminated hard flat plate 81) in which five hard flat plates (80 mm long × 200 mm wide × 5 mm thick) are stacked in the thickness direction are placed in the vertical direction LD. They were arranged with an interval J (150 mm).
(2) A second sheet was cut into a rectangle (length 200 mm×width 100 mm) to obtain a test piece 80 . The physical properties of the second sheet were as follows. The fineness was 4.0 dtex for the inner layer, 5.0 dtex for the intermediate layer, and 6.0 dtex for the outer layer. The contact angles (average of 5 points) were 55° for the inner layer, 110° for the intermediate layer, and 42° for the outer layer. The voids between the fibers were 900 μm in the inner layer, 700 μm in the intermediate layer, and 400 μm in the outer layer. The basis weight was 5 g/m ² for the inner layer, 30 g/m ² for the intermediate layer, and 10 g/m ² for the outer layer. The thickness of the inner layer was 1.5 mm, the intermediate layer was 4.0 mm, and the outer layer was 1.5 mm. Synthetic fibers used for the inner layer, intermediate layer, and outer layer were PET/PE bico resin. The mass of the test piece was 2.2 g.
(3) The test piece 80 was expanded in a developed state so that the test piece 80 straddles the first laminated hard flat plate 81 and the second laminated hard flat plate 81 in the horizontal direction. A weight 82 of 100 g (20 mm long x 100 mm wide) is placed on each side of the test piece 80 in the horizontal direction, and the weight 82 and the laminated hard flat plate 81 sandwich both ends of the test piece 80 to spread the test piece 80. to prevent wrinkles from forming.
(4) Using a syringe containing 2 mL of simulated stool, the simulated stool 83 was dropped onto the center of the test piece 80 at 0.4 mL/sec. The syringe used was a 10 ml Renault chip type (manufactured by HENKESASSWOLF) with an extraction aperture of 2 mm.
(5) The mass of the test piece 80 was measured after the test piece 80 was allowed to stand for 5 minutes after dripping of pseudo feces stopped occurring.
(6) Cut out a blank test piece using PE/PP bico durable hydrophilic 5.6dt 40g/m ² instead of the second sheet in (2) above, and perform the above test procedures (2) to (5) in the same manner. gone. Here, "test piece 80" shall be read as "blank test piece". The physical properties of the blank test piece were 5.6 dtex fineness, 1000 μm inter-fiber gap, 5 mm thickness, and 1.9 g mass.
The above test operation was performed five times on the test piece 80, and test examples 16 to 20 were obtained. In addition, the blank test piece was repeated 5 times, and Test Examples 21 to 25 were obtained. Tables 4 and 5 show the test results. The values in the table (pseudo-stool retained amount) are numerical values obtained by the following formula.
(Amount of pseudo feces retained (g)) = (mass of test piece measured by operation (5) above) - (mass of test piece measured by operation (2) above) Equation (1)
(Amount of pseudo feces retained (g)) = (mass of blank test piece measured in operation (5) to replace in (6) above) - (blank test piece measured in operation (2) to replace in (6) above) mass)...Equation (2)

When comparing the average values, the test piece 80 holds less pseudo feces than the blank test piece. From this, it can be seen that loose stools and the like easily permeate the second sheet of the present embodiment.

<Description of terms in the specification>
When the following terms are used in the specification, they shall have the following meanings, unless stated otherwise in the specification.
- "Front-back (longitudinal) direction" means a direction connecting the ventral side (front side) and the dorsal side (rear side), and "width direction" means a direction (horizontal direction) perpendicular to the front-back direction.

- "Inside" means the side closer to the wearer's skin, and is also called the skin-contacting side. "Outer side" means the side farther from the wearer's skin and is also referred to as the non-skin contacting side. "Inner surface" means the surface of the member closer to the wearer's skin, and "outer surface" means the surface farther from the wearer's skin.

・"LD direction" and "WD direction" mean the flow direction (LD direction) and the transverse direction (WD direction) perpendicular to this in the manufacturing equipment, one of which is the front-back direction of the product. , and the other is the width direction of the product. The LD direction of the nonwoven fabric is the direction of fiber orientation of the nonwoven fabric. The fiber orientation is the direction along which the fibers of the nonwoven fabric are aligned. It can be determined by a simple measurement method for determining the orientation direction.

- "Unfolded state" means a flat unfolded state without contraction or slack.

- "Gel strength" is measured as follows. Artificial urine (urea: 2 wt%, sodium chloride: 0.8 wt%, calcium chloride dihydrate: 0.03 wt%, magnesium sulfate heptahydrate: 0.08 wt%, and deionized water: 97.09 wt%) 1.0 g of superabsorbent polymer is added to 49.0 g and stirred with a stirrer. The resulting gel is left in a thermo-hygrostat at 40° C. and 60% RH for 3 hours, then returned to room temperature, and the gel strength is measured with a card meter (Curdmeter-MAX ME-500 manufactured by I. techno Engineering).

- "Matsuke" is measured as follows. After pre-drying the sample or test piece, it is left in a test room or apparatus under standard conditions (test location: temperature 23±1° C., relative humidity 50±2%) to a constant weight. Pre-drying refers to making a sample or test piece constant weight in an environment at a temperature of 100°C. Fibers with an official moisture content of 0.0% do not need to be pre-dried. Using a sampling template (100 mm x 100 mm), a sample with dimensions of 100 mm x 100 mm is cut from the constant weight specimen. The weight of the sample is measured, multiplied by 100 to calculate the weight per square meter, and used as basis weight.

- "Thickness" is automatically measured using an automatic thickness gauge (KES-G5 handy compression tester) under the conditions of a load of 0.098 N/cm ² and a pressurized area of 2 cm ² .

・The “water absorption” is measured according to JIS K7223-1996 “Testing method for water absorption of super absorbent polymer”.

・"Water absorption rate" is "Time to end point" when JIS K7224-1996 "Test method for water absorption rate of superabsorbent polymer" is performed using 2g of superabsorbent polymer and 50g of physiological saline. and

- "The space between fibers" can be determined by measuring the shortest distance between fibers. For example, the distance from a specific point (first point) on the first fiber to the nearest point (second point) from the first point on another fiber closest to the same fiber is obtained by measuring be able to. This distance is similarly measured between other fibers. This measurement is repeated 10 times, and the range between the minimum value and the maximum value of the obtained measurement values is defined as the range of voids between fibers. Alternatively, an average value may be obtained from numerical values of the results of repeated measurements.

ここで、Ｄ：繊維径（μｍ）、ｐ：繊維密度（ｇ／ｃｍ³）、ｔ：厚み（ｍｍ）、ｗ：目付け（ｇ／ｍ²）である。繊維密度ｐは、密度勾配管を使用して、ＪＩＳ Ｌ１０１５化学繊維ステープル試験方法に記載の密度勾配管法の測定方法に準じて測定する。繊維径Ｄ（μｍ）は走査型電子顕微鏡を用いて、カットした繊維の繊維断面を１０本測定し、その平均値を繊維径とする。 - Also, the average inter-fiber distance may be measured instead of the inter-fiber gap. The "average inter-fiber distance" is obtained by the following equation (3) based on Wrotnowski's assumption. Wrotnowski's assumption is that the fibers are cylindrical and regularly oriented without intersecting each other.

Here, D: fiber diameter (μm), p: fiber density (g/cm ³ ), t: thickness (mm), w: basis weight (g/m ² ). The fiber density p is measured using a density gradient tube according to the density gradient tube method described in JIS L1015 Chemical Fiber Staple Test Method. The fiber diameter D (μm) is obtained by measuring 10 fiber cross sections of cut fibers using a scanning electron microscope, and taking the average value as the fiber diameter.

・If there is no description of environmental conditions for testing or measurement, the test or measurement shall be performed in a laboratory or equipment under standard conditions (test location: temperature 23±1°C, relative humidity 50±2%). do.

・Unless otherwise specified, the dimensions of each part mean the dimensions in the unfolded state, not in the natural length state.

22... Top sheet, 21... Impermeable sheet such as loose stools, 23... Absorbent element, 24... Gather sheet, 25... Back sheet, 26... Second sheet, H... Permeation hole of top sheet , LD... Longitudinal direction (flow direction and The front and rear directions are also the same in the illustrated example, so the same reference numerals are used .

Claims (5)

A top sheet that permeates diarrheal stool, a second sheet that is adjacent to the outside of the top sheet and that permeates the diarrheal stool , and an absorbent element arranged outside the second sheet,
The second sheet is a laminated nonwoven fabric composed of an inner layer, an outer layer, and an intermediate layer interposed therebetween,
where r1 is the degree of water repellency of the inner layer, r2 is the degree of water repellency of the intermediate layer, and r3 is the degree of water repellency of the outer layer, satisfying the relationship r2>r1>r3;
When the gap between fibers in the inner layer is s1, the gap between fibers in the intermediate layer is s2, and the gap between fibers in the outer layer is s3, the relationship s3 < s2 ≤ s1 is satisfied,
The contact angle of the inner surface layer is 30° to 70°, the contact angle of the intermediate layer is in the range of 70° to 170° and is 1.3 to 2.5 times the contact angle of the inner surface layer,
The second sheet has a thickness of 3 to 20 mm,
the intermediate layer is thicker than the inner layer and the outer layer;
An absorbent article characterized by: The size of voids between fibers in the inner layer is 800 μm or more and 1000 μm or less, the size of voids between fibers in the intermediate layer is more than 600 μm to 800 μm or less, and the size of voids between fibers in the outer layer is 200 μm. not less than 600 μm or less,
The absorbent article according to claim 1. The laminated nonwoven fabric is obtained by laminating short fibers coated with a water repellent agent in the order of an outer layer, an intermediate layer and an inner layer, and then passing hot air from the inner surface side to the outer surface side to fuse the fibers. An air-through nonwoven fabric with a total basis weight of 15 to 60 g / m ² ,
The absorbent article according to claim 1 or 2. The top sheet is provided with a plurality of rows of permeable holes arranged in the front-rear direction at predetermined intervals in the width direction,
The effective opening area of each of the transmission holes is 10,000 to 50,000 mm ² ,
the group of permeation holes is formed in an excretion area including at least a part of the top sheet where the diarrhea is excreted and its surroundings;
The opening area ratio of the transmission hole group with respect to the top sheet is 20 to 50%,
The absorbent article according to claim 1. The top sheet is a nonwoven fabric made of water-repellent or hydrophobic fibers, and the fineness of the fibers is 4.0 to 6.0 dtex.
The absorbent article according to claim 4.

Images