JP7342513B2 - absorbent articles - Google Patents

Description

The present invention relates to absorbent articles such as paper diapers and sanitary napkins.

BACKGROUND ART Conventionally, absorbent articles are provided with an absorbent body extending in a longitudinal direction connecting the abdomen side and the back side of the wearer, for example, as disclosed in Patent Document 1. This absorber absorbs excreted liquids such as urine and menstrual blood. By placing this absorbent body between a liquid-permeable top sheet and a liquid-impermeable back sheet, the absorbent article absorbs urine excreted into the top sheet, and the absorbent body absorbs urine. The back sheet prevents urine from leaking out.

International Publication No. 2016/114209

By the way, as a liquid-permeable material constituting the top sheet, for example, a nonwoven fabric is used. Nonwoven fabrics can provide a soft touch, and are therefore suitable as a material for top sheets that come into contact with the wearer's skin. However, in addition to urine and menstrual blood, the wearer excretes stool and watery stool. Stool is mostly solid matter, and watery stool is a mixture of solid matter and liquid. The absorbent body of the absorbent article is not capable of absorbing solid matter. Thus, if a wearer of an absorbent article excretes stool or watery stool, the absorbent article is replaced.

When replacing the absorbent article, it is necessary to perform the replacement work so as not to remove excrement remaining on the top sheet from the absorbent article. However, in the case of watery stool, since the liquid is mixed with solid matter, it is difficult to absorb into an absorbent body compared to urine. Therefore, watery stool, when compared to urine and feces, can back up and leak out of the absorbent body when the absorbent article is removed from the wearer.

Therefore, an object of the present invention is to provide an absorbent article that can suppress the return of watery stool from the absorbent body.

In order to solve the above problems, in the present invention, a plurality of liquid-permeable sheets covering the wearer-side surface of the absorbent body are provided with a plurality of liquid-permeable sheets each having an airflow resistance within the range of 0.0058 to 0.0289 kPa・sec/m. At least one of the plurality of liquid-permeable sheets had a ventilation resistance within the range of 0.0183 to 0.0289 kPa·sec/m.

Specifically, the present invention relates to an absorbent article that is attached to the crotch of a wearer, and includes an absorbent core and a plurality of liquid-permeable sheets that cover a surface of the absorbent core on the wearer's side. All of the liquid-permeable sheets have ventilation resistance within the range of 0.0058 to 0.0289 kPa·sec/m, and at least one of the liquid-permeable sheets has ventilation resistance of 0.0183. It is within the range of ~0.0289 kPa·sec/m.

In addition, among the plurality of liquid permeable sheets, the ventilation resistance of the sheet closest to the absorber is within the range of 0.0183 to 0.0289 kPa・sec/m, and the ventilation resistance of the other sheets is 0.
．． It may be within the range of 0.0058 to 0.0289 kPa·sec/m.

Further, among the plurality of liquid-permeable sheets, the static friction coefficient of the sheet closest to the wearer may be in a range exceeding 0.34.

Further, the absorbent body may have at least two or more layers, and the layer on the wearer side may contain particles of SAP, which is a superabsorbent polymer, in a larger amount than the other layers.

The absorbent article described above can improve the absorbency of watery stool.

FIG. 1 is a perspective view of a diaper according to an embodiment. FIG. 2 is an exploded perspective view of the diaper. FIG. 3 is a cross-sectional view of the diaper in a non-wearing state, taken along the width direction at the center in the longitudinal direction. FIG. 4 is a diagram explaining the test method for verifying the reversion of watery stool. FIG. 5 is a diagram showing the types of core wrap sheets of test samples prepared for verification. FIG. 6 is a diagram showing the test results. FIG. 7 is a diagram showing the measurement results of ventilation resistance. FIG. 8 is a diagram showing the measurement results of the friction coefficient.

EMBODIMENT OF THE INVENTION Below, the absorbent article based on embodiment of this invention is demonstrated with reference to drawings. Note that the configurations of the following embodiments are illustrative, and the present invention is not limited to the configurations of these embodiments.

<Embodiment>
In this embodiment, a tape-type disposable diaper (which is an example of an "absorbent article" in the present application, and hereinafter simply referred to as a "diaper") will be described with the front body and the back facing the wearer's abdomen. The longitudinal direction is the direction that connects the back body which is arranged as a front body. Between the front body (on one side in the longitudinal direction) and the back body (on the other side in the longitudinal direction) (at the center in the longitudinal direction) is an inseam that is placed at the wearer's crotch (located opposite the crotch). Department is located. In addition, when the disposable diaper is worn on the wearer (hereinafter referred to as the "wearing state"), the side facing the wearer's skin (inner side when worn) is the skin side, and the side opposite to the skin side. (outside when worn) is the non-skin side. Further, the direction connecting the skin side and the non-skin side is defined as the thickness direction, and the direction perpendicular to both the longitudinal direction and the thickness direction is defined as the width direction. In addition, viewing from the thickness direction is considered to be a planar view.

FIG. 1 is a perspective view of a diaper according to this embodiment. The diaper 1 has a crotch area 1B that corresponds to the crotch area that covers the genitals of the wearer when worn, and a front body area 1F that is located in front of the crotch area 1B and corresponds to the front body of the wearer. and a back body region 1R, which is located behind the crotch region 1B and corresponds to the wearer's back body. Tapes 2L and 2R that can be attached to the front patch 2F provided on the non-skin side surface of the front body region 1F are provided on both left and right edges of the back body region 1R. Therefore, in the diaper 1, when the tapes 2L and 2R are attached to the front patch 2F with the front body region 1F disposed on the ventral side of the wearer and the back body region 1R disposed on the wearer's dorsal side, , is fixed to the wearer's body in a state surrounding the wearer's waist and thighs. Since the diaper 1 is fixed to the wearer's body in this manner, the wearer can stand and walk while wearing the diaper 1. Examples of wearers include elderly people and adults who excrete about 150 ml of urine.

In the diaper 1, a mat 6 capable of absorbing and retaining liquid is arranged mainly around the crotch region 1B. The diaper 1 also includes three-dimensional gathers 3BL and 3BR in areas surrounding the wearer's thighs in order to suppress the formation of gaps that serve as liquid outflow paths between the diaper 1 and the wearer's skin. is provided, and waist gathers 3R are provided in a region surrounding the wearer's abdominal circumference. The three-dimensional gathers 3BL, 3BR and the waist gathers 3R adhere to the wearer's skin due to the elasticity of the rubber thread. Therefore, liquid excreted from the wearer's genitals is absorbed into the mat 6 of the diaper 1 without leaking from the diaper 1.

FIG. 2 is an exploded perspective view of the diaper 1. Further, FIG. 3 is a cross-sectional view of the diaper 1 in a non-wearing state, taken along the width direction at the center in the longitudinal direction. The diaper 1 has a cover sheet 4 that forms an outer surface in the worn state. The cover sheet 4 is a sheet-like member having a substantially rectangular appearance with constrictions 4KL and 4KR on the long sides, and forms the exterior surface of the diaper 1. The constrictions 4KL and 4KR are provided at locations where the wearer's thighs are located. The cover sheet 4 is provided to reinforce the back sheet 5 and improve its feel. For example, in order to suppress the leakage of excrement, a nonwoven fabric made of a liquid-impermeable thermoplastic resin may be used as its material. can. Examples of liquid-impermeable thermoplastic resins include polyethylene (PE) and polypropylene (PP). The cover sheet 4 is not limited to a single layer structure, but may have a multilayer structure including an inner cover sheet and an outer cover sheet.

The diaper 1 includes a back sheet 5, a mat 6, and a top sheet 7, which are laminated in this order on the skin-side surface of the cover sheet 4. The back sheet 5, mat 6, and top sheet 7 are all sheet-like members having a substantially rectangular appearance, and are laminated in order on the cover sheet 4 with their longitudinal directions coinciding with the longitudinal direction of the cover sheet 4. . Like the cover sheet 4, the back sheet 5 is a sheet made of liquid-impermeable thermoplastic resin in order to suppress leakage of excrement. Further, the top sheet 7 is a sheet-like member that is placed on the wearer's skin side so as to cover the water-absorbing surface of the mat 6. This top sheet 7 has liquid permeability in part or in whole. Therefore, when the diaper 1 is worn, liquid excreted by the wearer enters the mat 6 through the top sheet 7 that can come into contact with the wearer's skin, and is absorbed there. For example, woven fabric, non-woven fabric, and porous film can be used as the material for the top sheet 7. The top sheet 7 may have hydrophilic properties.

The backsheet 5, mat 6, and topsheet 7 all extend from the front body region 1F to the back body region 1R. Therefore, when the wearer's private parts are covered with the cover sheet 4 in which the back sheet 5, the mat 6, and the top sheet 7 are laminated, both longitudinal ends of the back sheet 5, the mat 6, and the top sheet 7 are covered by the wearer's genitals. It is located on the ventral and dorsal sides of the body. That is, the wearer's genitals are covered with the mat 6 from the ventral side to the back side of the wearer. Therefore, even if the wearer excretes liquid from the body in either a posture with the belly facing downward or a posture with the back facing downward, the excreted liquid will come into contact with the mat 6 via the top sheet 7. It turns out.

Moreover, the diaper 1 has elongated strip-shaped side sheets 8L and 8R for forming the three-dimensional gathers 3BL and 3BR described above. The side sheets 8L and 8R are liquid-impermeable sheets provided on the long sides of the top sheet 7. Similar to the three-dimensional gathers 3BL and 3BR of the diaper 1, the side sheets 8L and 8R are provided with constrictions 8KL and 8KR at locations where the wearer's thighs are located. Rubber threads 8EL and 8ER are woven into the side sheets 8L and 8R along the longitudinal direction. Therefore, when the diaper 1 is put on, that is, when the diaper 1 is U-shaped in side view, the side sheets 8L and 8R are pulled in the longitudinal direction by the contraction force of the rubber threads 8EL and 8ER, and the top sheet 7 It rises up and becomes a three-dimensional gather that prevents liquid from flowing out.

Further, the rubber thread 9ER for forming the above-mentioned waist gathers 3R is provided between the back sheet 5 and the top sheet 7 at a position further back than the end of the mat 6. The rubber thread 9ER is provided between the backsheet 5 and the topsheet 7 such that the longitudinal direction, which is the stretching direction, is the left-right direction of the diaper 1. Therefore, when the tapes 2L and 2R provided on both the left and right sides of the rubber thread 9ER are attached to the front patch 2F on the ventral side of the wearer, the rubber thread 9ER exerts a contractile force to attach the diaper 1 to the wearer. This prevents a gap from being formed between the diaper 1 and the wearer's abdominal circumference. Note that the cover sheet 4 is also provided with rubber threads 4SL and 4SR along the longitudinal direction to prevent a gap from being formed between the diaper 1 and the wearer's abdominal circumference. The rubber threads 4SL and 4SR are provided at appropriate positions in an appropriate number determined according to the elastic force (shrinkage force) required in the design of the diaper 1.

Mat 6 applies water to the gaps between short fibers of cellulose fibers such as pulp fibers, rayon fibers, or cotton fibers, and short fibers made of synthetic fibers such as polyethylene, polypropylene, or polyethylene terephthalate that have been subjected to hydrophilic treatment. It has a structure that holds particulate absorbent resin such as SAP (Super Absorbent Polymer), which is a hydrophilic polymer with a crosslinked structure that can absorb and retain it. Therefore, in the mat 6, the volume change of the absorbent resin before and after absorbing liquid basically occurs within the short fibers that hold the absorbent resin in the gaps. Therefore, when looking down on the entire mat 6, it can be said that the expansion rate of the thickness of the mat 6 that has absorbed liquid is not as large as the expansion rate of the absorbent resin itself.

The SAP particles of this embodiment refer to particles of a resin composition containing SAP. The "resin composition containing SAP" as used herein refers to both compositions consisting only of SAP and compositions containing SAP as a main component and containing other substances to the extent that they do not adversely affect water absorption. It is a concept that encompasses Examples of "other substances" include additives (such as a surface modifier added for the purpose of making the particle surface hydrophobic), unreacted monomers remaining during the synthesis of SAP, and the like.

By the way, as shown in FIG. 3, the mat 6 of the above embodiment includes a core 6C (an example of an "absorbent material" in the present application) in which SAP is mixed with pulverized pulp (so-called "fluff pulp"). It is wrapped with core wrap sheet 6W. In the diaper 1, the skin-side surface of the core 6C (corresponding to the "wearer-side surface" in the present application) is a part of the core wrap sheet 6W that wraps around the core 6C, and a part of the core wrap sheet 6W that wraps the core 6C. The core 6C is covered with a laminated portion that overlaps the top sheet 7 covering the core 6C. Since both the core wrap sheet 6W and the top sheet 7 are liquid permeable sheets, the laminated portion has liquid permeability.

In the diaper 1 of this embodiment, the core wrap sheet 6W that covers the skin side surface of the core 6C and the top sheet 7 both have ventilation resistance within the range of 0.0058 to 0.0289 kPa·sec/m. For any one of them, the ventilation resistance is within the range of 0.0183 to 0.0289 kPa·sec/m. This ventilation resistance is a value measured by an air permeability tester (KES-FB-AP1) manufactured by Kato Tech Co., Ltd. Therefore, the diaper 1 of the present embodiment has an excellent ability to suppress the return of watery stool from the absorbent body, as described below, compared to the diaper of the comparative example whose ventilation resistance or coefficient of static friction is outside this range. ing. Reversion means that moisture absorbed by pulp or SAP oozes out again due to pressurization or the like.

<Verification of reversal>
FIG. 4 is a diagram explaining the test method for verifying the reversion of watery stool. In this verification, a mat with a width of 280 mm and a length of 560 mm was used as a test sample corresponding to Mat 6. The reagent was dropped in the second area from the back of the absorber divided into five equal parts in the longitudinal direction. Drop 200 ml of reagent and allow the test sample to absorb the reagent. Then, 10 minutes after dropping the reagent, as shown in FIG. 4(B), a square filter paper is placed on the test sample, a 100 mm square acrylic plate is placed on top of the test sample, and a weight of 20 kg is placed on the test sample. Then, as shown in FIG. 4(C), the pressurized state with a weight is maintained for 5 minutes. Thereafter, as shown in FIG. 4(D), the square filter paper is weighed using an electronic balance, and the amount of change in the weight of the square filter paper before and after the main verification is measured. In this verification, a test sample with a relatively small amount of change is considered to be an excellent sample with a small amount of reversion.

In this verification, eight types of test samples were prepared and the amount of reversion of each was compared. The eight types of test samples were made by alternating the types of core wrap sheets surrounding the core and sheets stacked on the core wrap sheets, but all had the same core. The core was made of pulp (width: 280 mm, length: 560 mm) with a basis weight of 260 g/cm ² and containing no SAP. FIG. 5 is a diagram showing the types of core wrap sheets of test samples prepared in this verification.

In FIG. 5, among the eight types of test samples, those corresponding to the combination of the mat 6 and top sheet 7 of the above embodiment are designated as "Examples 1 to 5", and those corresponding to the comparative examples are designated as "Comparative Examples 1 to 5". 3".

In Examples 1 to 3, a nonwoven fabric made by an air-through method was used for the core wrap sheet and the sheet stacked on the core wrap sheet. Air-through type nonwoven fabrics are formed by carding (spreading) raw material fibers and then thermally fusing them with hot air treatment. The basis weight of the core wrap sheet is 20.0 g/m ² in Examples 1 and 3, and 22.0 g/m ² in Example 2.

Further, in Examples 4 and 5, a nonwoven fabric made by a spunbond method is used for the core wrap sheet and the sheet stacked on the core wrap sheet. The basis weight of the core wrap sheet is 18.0 g/m ² in Example 4 and 17.5 g/m ² in Example 5. Spunbond nonwoven fabric is formed by carding raw material fibers, entangling the fibers with high-pressure water to form a sheet, and drying it.

Furthermore, in Comparative Examples 1 to 3, pulp was used for the core wrap sheet and the sheet stacked on the core wrap sheet. The basis weight of the pulp is 19.5 g/m ² in Comparative Example 1, 16.0 g/m ² in Comparative Example 2, and 14.0 g/m ² in Comparative Example 3.

In addition, the reagent used in this verification was prepared by adding bentonite to ion-exchanged water and stirring it, and the reagent prepared within 3 days was used as a simulant of watery stool. The reagent has a water content of 94% by weight (for example, 1 kg of reagent is prepared by mixing 940 g of water and 60 g of bentonite).

When the amount of watery stool returned was verified for these eight types of test samples, all of Examples 1 to 5 had better results than Comparative Examples 1 to 3. FIG. 6 is a diagram showing the test results.

As can be seen from FIG. 6, in Comparative Examples 1 to 3, the amount of reagent returned was at least 14.3 g on average. On the other hand, in all of Examples 1 to 5, the amount of reagent returned was 9.9 g or less on average. In particular, in Examples 4 and 5, in which a nonwoven fabric made by the spunbond method was used for the core wrap sheet, the amount of reagent returned was 5.7 g at the maximum on average, and compared to Comparative Examples 1 to 3, it was watery. It was confirmed that the amount of relapse was significantly small.

The physical properties of each material used as the core wrap sheet and the sheet stacked on the core wrap sheet were confirmed using the above test samples, and the confirmation results are shown below. Whether watery feces remains on the mat without returning to the surface of the core wrap sheet is thought to be largely influenced by the size of the fine openings formed by the material covering the surface of the core. Therefore, in this confirmation, we confirmed the air permeability (airflow resistance), which is thought to have a direct correlation with the size of the opening.

<Air permeability>
In this verification, the air permeability resistance of the core wrap sheet was measured using an air permeability tester (KES-F8-AP1) manufactured by Kato Tech Co., Ltd. FIG. 7 is a diagram showing the measurement results of ventilation resistance.

As can be seen from FIG. 7, in Examples 1 to 5, it was confirmed that the airflow resistance of the top sheet and core wrap sheet was within the range of 0.0058 to 0.0289 kPa·sec/m. Ta. Furthermore, in Examples 1 to 5, it was confirmed that the ventilation resistance of the core wrap sheet was higher than that of the top sheet, and that the ventilation resistance was within the range of 0.0183 to 0.0289 kPa·sec/m. . On the other hand, in Comparative Examples 1 to 3, the ventilation resistance was outside this range. From this, it can be seen that the ventilation resistance of the liquid-permeable sheet covering the skin-side surface of the core is within the range of 0.0058 to 0.0289 kPa・sec/m, and that any sheet has ventilation resistance. It can be seen that within the range of 0.0183 to 0.0289 kPa·sec/m, watery stool remains on the mat without returning to the surface of the core wrap sheet. Therefore, from this confirmation result, like the diaper 1 of the above embodiment, the ventilation resistance of the sheet covering the skin side surface of the absorber is within the range of 0.0058 to 0.0289 kPa・sec/m, and , for any sheet, absorbent articles with air permeability within the range of 0.0183 to 0.0289 kPa・sec/m are less likely to cause backflow of watery stool from the absorbent body than absorbent articles outside this range. It is recognized that it is possible to suppress the

<Static friction coefficient>
Next, the results of checking the coefficient of static friction on the surface of the top sheet will be explained. The static friction coefficient was measured using a surface property measuring device (Tribogear TYPE: 14DR) manufactured by Shinto Kagaku Co., Ltd. The measurement method was based on JISK7125. In this confirmation, we verified the liquid flow on the top sheet surface. In the verification of liquid flow, a mat with a width of 280 mm and a length of 560 mm was used, and the mat was placed on a slope with an inclination angle of 30 degrees so that its longitudinal direction coincided with the vertical direction of the slope. 50 g of a reagent simulating stool was dropped onto the mat at a position 450 mm from the bottom edge of the mat. In this verification, the distance that a reagent simulating watery stool flows on the mat surface (diffusion length: average value of 5 times) and the amount absorbed by the mat were confirmed. In this verification, all 50 g of the reagent was absorbed by the mat, and further, the one with the shorter diffusion length was superior. FIG. 8 is a diagram showing the measurement results of the coefficient of static friction.

As can be seen from FIG. 8, in all cases where the static friction coefficient of the top sheet surface was 0.59 or more, the reagent diffusion range remained within 450 mm, and the reagent did not flow out to the outside of the mat. On the other hand, in the case where the static friction coefficient of the top sheet surface was 0.34 or less, the reagent flowed over a distance longer than 450 mm, and the reagent flowed out to the outside of the mat. From this, if the top sheet surface has a coefficient of static friction in the range exceeding 0.34 (larger than 0.34), it is easier to absorb water than absorbent articles with a coefficient of static friction of 0.34 or less. It is recognized that the absorbability of feces is excellent when excreted. Further, if the coefficient of static friction is 0.59 or more, it is recognized that the absorbency when watery stool is excreted is better. Furthermore, if the coefficient of static friction is in a range exceeding 0.74, it is recognized that the absorbency when watery stool is excreted is even better. Further, if the coefficient of static friction is 0.98 or more, it is recognized that the absorbency when watery stool is excreted is even better.

In addition, in the diaper 1, among the plurality of liquid-permeable sheets that cover the wearer side surface of the core 6C, the sheet closest to the core 6C has a ventilation resistance that is lower than that of the other liquid-permeable sheets among the plurality of liquid-permeable sheets. The ventilation resistance may be higher than that of the According to this, the liquid that has passed through the sheet and been absorbed by the core 6C remains in the core 6C, and the possibility of the sheet returning back can be further suppressed. For example, between the core wrap sheet 6W and the top sheet 7 that cover the skin side surface of the core 6C, if the ventilation resistance of the core wrap sheet 6W is made higher than that of the top sheet 7, the top sheet 7 and the core The liquid that has passed through the wrap sheet 6W and been absorbed into the core 6C remains within the core wrap sheet 6W, reducing the possibility that the liquid in the core 6C will flow back through the core wrap sheet 6W.

Further, in the diaper 1, the core 6C has at least two or more layers, and the layer on the skin side may contain a larger amount of SAP particles than the other layers. If the layer on the skin side of the core 6C, which has two or more layers, contains more SAP particles than the other layers, the moisture absorption in the skin side part of the core 6C will be higher, resulting in a matte finish. It becomes possible to further suppress the return of watery stool from 6.

Further, in the above embodiment, a tape-type disposable diaper is exemplified, but the present invention is also applicable to other forms of absorbent articles. Examples of such absorbent articles include various types of absorbent articles with gathers, such as pants-type disposable diapers, urine pads, and light incontinence pads, and flat absorbent articles without gathers.

1...Diaper 1B...Inseam area 1F...Front body area 1R...Back body area 2F...Front patch 2L, 2R...Tape 3BL, 3BR...3D gathers 3R...Waist gathers 4...Cover sheet 4KL , 4KR...Bound 5...Back sheet 6...Mat 6C...Core 6W...Core wrap sheet 7...Top sheet 8...Side sheet 8KL, 8KR...Bound 4SL, 4SR, 8EL, 8ER, 9ER...・Thread rubber

Claims (3)

An absorbent article worn under the crotch of a wearer,
absorber and
a plurality of liquid-permeable sheets covering the wearer side surface of the absorbent body,
Each of the plurality of liquid permeable sheets has an airflow resistance within a range of 0.0058 to 0.0289 kPa·sec/m,
At least one of the plurality of liquid-permeable sheets has an airflow resistance within the range of 0.0183 to 0.0289 kPa·sec/m,
Among the plurality of liquid-permeable sheets, the sheet closest to the wearer has a coefficient of static friction of 0.98 or more.
Absorbent articles. Among the plurality of liquid-permeable sheets, the sheet closest to the absorbent body has a ventilation resistance higher than the other sheets, and the sheet closest to the absorbent body has a ventilation resistance of 0.0183 to 0.0. 0289kPa・sec/m, and the ventilation resistance of the other sheet is within the range of 0.0058 to 0.0289kPa・sec/m.
The absorbent article according to claim 1. The absorbent body has at least two or more layers, and the layer on the wearer side contains particles of SAP, which is a superabsorbent polymer, in a larger amount than the other layers.
The absorbent article according to claim 1 or 2 .

Images