JP7777914B2 - napkin set - Google Patents

Description

The present invention relates to a napkin set .

Sanitary napkins containing absorbents have traditionally been widely used as feminine hygiene products for absorbing bodily fluids. A method has been proposed for efficiently using sanitary napkins by layering an auxiliary napkin on the skin-facing side of the sanitary napkin to improve its ability to absorb bodily fluids, etc. For example, Patent Document 1 discloses an absorbent article for attaching an auxiliary pad, in which an auxiliary pad 2 that fits closely to the labia is attached to the body-facing (skin-facing) side of a sanitary napkin 1 for attaching the auxiliary pad.

Japanese Patent Application Laid-Open No. 2003-38564

When using such auxiliary napkins, there is a growing demand to extend the life of sanitary napkins by replacing only the auxiliary napkin that has absorbed bodily fluids and reducing the frequency of replacing the sanitary napkin itself. In such a usage method, the ease of replacing the auxiliary napkin is important. For example, whether a user wants to replace only the auxiliary napkin without replacing the sanitary napkin, or whether a user wants to replace the sanitary napkin and auxiliary napkin together, it is desirable for the user to be able to perform the replacement process easily and without stress. However, while Patent Document 1 discloses that the absorbent article is equipped with a guide element that guides the attachment position when attaching the auxiliary pad (auxiliary napkin), it does not take into consideration the ease of replacing the auxiliary napkin or sanitary napkin.

The present invention was made in consideration of the above-mentioned problems with the conventional technology, and its purpose is to provide an auxiliary napkin that makes it easy to change sanitary napkins and auxiliary napkins.

The main invention to achieve the above object is:
A napkin set comprising a sanitary napkin and an auxiliary napkin attached to the skin side of the sanitary napkin,
The auxiliary napkin has an absorbent body and a liquid-impermeable backsheet disposed closer to the skin than the absorbent body,
the backsheet has an attachment portion on its non-skin side for attaching the auxiliary napkin to the skin side of the sanitary napkin;
The non-skin side of the sanitary napkin is provided with an adhesive portion for fixing the sanitary napkin to a user's underwear,
The entire area of the attachment portion in an unused state is attached to the skin side of a second auxiliary napkin having the same structure as the auxiliary napkin, and then the average magnitude of the force applied when peeling the auxiliary napkin from the second auxiliary napkin along the longitudinal direction of the auxiliary napkin is:
the adhesive portion in an unused state is attached to the skin-side surface of the second auxiliary napkin over the entire width direction and over a 50 mm area in the longitudinal direction, and then the force required to peel the sanitary napkin from the second auxiliary napkin along the longitudinal direction of the sanitary napkin is equal to or greater than the average force required;
The back sheet is configured to prevent menstrual blood from moving from the skin side to the non-skin side,
This napkin set is configured so that the auxiliary napkin can be removed from the sanitary napkin by pulling the auxiliary napkin while holding down the sanitary napkin, and so that the sanitary napkin can be removed together with the auxiliary napkin by pulling the auxiliary napkin without holding down the sanitary napkin .
Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

The present invention provides an auxiliary napkin that makes it easy to change sanitary napkins and auxiliary napkins.

1A and 1B are schematic plan views showing the auxiliary napkin 1 as viewed from the skin side and the non-skin side. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. 1A and 1B are schematic plan views showing the sanitary napkin 2 as viewed from the skin side and the non-skin side. FIG. 4 is a schematic cross-sectional view taken along line BB in FIG. 3. FIG. 2 is a schematic plan view showing the state in which an auxiliary napkin 1 is attached to the skin side of a sanitary napkin 2. 6A to 6C are perspective views illustrating how the auxiliary napkin 1 is attached and detached. 10 is a diagram illustrating a method for evaluating the peel strength of the attachment portion 31 of the auxiliary napkin 1. FIG. 1 is a table showing data obtained by measuring the peel strength of a first auxiliary napkin 1A relative to a second auxiliary napkin 1B. 10 is a diagram illustrating a method for evaluating the peel strength of the adhesive portion 41 of the sanitary napkin 2 relative to the second auxiliary napkin 1B. FIG. 10 is a table showing data measured regarding the peel strength of the sanitary napkin 2 relative to the second auxiliary napkin 1B. 10 is a table showing the results of verifying the change in peel strength when the attachment part 31 of the auxiliary napkin 1 is repeatedly attached and detached. 10 is a diagram illustrating a method for evaluating the peel strength of the adhesive portion 41 of the sanitary napkin 2. FIG. 10 is a table showing the results of measuring the peel strength of the adhesive portion 41 for several types of sanitary napkins 2.

At least the following matters will become clear from the description of this specification and the accompanying drawings.
An auxiliary napkin having longitudinal and width directions that intersect with each other and that is attached to the skin-side surface of a sanitary napkin, wherein the non-skin-side surface of the auxiliary napkin has an attachment portion for attaching the auxiliary napkin to the skin-side surface of the sanitary napkin, and the non-skin-side surface of the sanitary napkin has an adhesive portion for securing the sanitary napkin to a user's underwear, and the average magnitude of force required when attaching the entire area of the attachment portion in an unused state to the skin-side surface of a second auxiliary napkin having the same configuration as the auxiliary napkin and then peeling the auxiliary napkin from the second auxiliary napkin along the longitudinal direction is greater than or equal to the average magnitude of force required when adhering the entire width direction and a 50 mm area of the adhesive portion in an unused state to the skin-side surface of the second auxiliary napkin and then peeling the sanitary napkin from the second auxiliary napkin along the longitudinal direction of the sanitary napkin.

With this type of auxiliary napkin, it is possible to remove just the auxiliary napkin from the sanitary napkin by pulling the auxiliary napkin lengthwise while holding down the sanitary napkin. On the other hand, it is possible to remove the sanitary napkin together with the auxiliary napkin by pulling the auxiliary napkin lengthwise without holding down the sanitary napkin. This allows the user to easily change the auxiliary napkin and the sanitary napkin.

It is desirable that, in such an auxiliary napkin, the average magnitude of the force required when attaching the entire area of the attachment portion in an unused state to the skin-side surface of the second auxiliary napkin and then peeling the auxiliary napkin from the second auxiliary napkin along the width direction is equal to or greater than the average magnitude of the force required when attaching the entire width direction and a 50 mm area in the longitudinal direction of the adhesive portion in an unused state to the skin-side surface of the second auxiliary napkin and then peeling the sanitary napkin from the second auxiliary napkin along the width direction of the sanitary napkin.

With this type of auxiliary napkin, it is possible to remove just the auxiliary napkin from the sanitary napkin by pulling the auxiliary napkin widthwise while holding down the sanitary napkin. On the other hand, it is possible to remove the sanitary napkin together with the auxiliary napkin by pulling the auxiliary napkin widthwise without holding down the sanitary napkin. This allows the user to easily change the auxiliary napkin and the sanitary napkin.

It is desirable that the length of such an auxiliary napkin in the longitudinal direction be shorter than the length of the sanitary napkin in the longitudinal direction.

With such an auxiliary napkin, even if liquid leaks outside the auxiliary napkin, it is absorbed by the sanitary napkin's absorbent body, making it less likely to stain the user's (wearer's) underwear. Furthermore, when attaching the auxiliary napkin, strict longitudinal positioning is not required, and when removing the auxiliary napkin, the auxiliary napkin that has absorbed menstrual blood is less likely to come into contact with the wearer's underwear. This makes it easier to put on and take off the auxiliary napkin.

It is desirable that such an auxiliary napkin has a first fold and a second fold, which are to be used when packing the sanitary napkin, at different positions in the longitudinal direction of the sanitary napkin, and that the length of the auxiliary napkin in the longitudinal direction is longer than the distance between the first fold and the second fold in the longitudinal direction of the sanitary napkin.

With this type of auxiliary napkin, when placing the auxiliary napkin on the skin side of the sanitary napkin, the position of the auxiliary napkin can be adjusted using the folds F1 and F2 as reference points. This makes the process of attaching the auxiliary napkin 1 easier.

In such an auxiliary napkin, it is desirable that the color of the sanitary napkin and the color of the auxiliary napkin are different.

With such an auxiliary napkin, the outline of the auxiliary napkin is easily visible even when it is placed over the sanitary napkin. This makes it easier for the user to determine whether the auxiliary napkin is properly attached to the sanitary napkin. It also makes it easier to know where to grab the auxiliary napkin when removing it.

It is desirable that the color of such an auxiliary napkin be within the range of hue numbers 4 to 9 on the Ostwald color wheel.

This type of auxiliary napkin has a red-based absorbent body, which has the effect of concealing absorbed menstrual blood. This allows the user to dispose of the used auxiliary napkin without worrying about being seen by others, making it easier to change auxiliary napkins without worrying about being seen by others.

In such an auxiliary napkin, it is desirable that the attachment portion be detachable from the skin side of the sanitary napkin.

This type of auxiliary napkin allows the auxiliary napkin to be attached and removed from the skin side of the sanitary napkin multiple times. This makes it easy to change or adjust the position of the auxiliary napkin after it has been attached, making the process of attaching the auxiliary napkin even easier.

In such a supplemental napkin, it is desirable that the attachment portion includes a hook-and-loop fastener.

With this type of auxiliary napkin, the engagement force of the hook-and-loop fastener is unlikely to decrease even when the attachment part is attached to the skin-side surface of the sanitary napkin and then removed. This means that the attachment part can be repeatedly attached and detached from the sanitary napkin, making the process of attaching the auxiliary napkin easier.

It is desirable that such an auxiliary napkin have a predetermined gap in the longitudinal direction between one end of the attachment portion and the other end of the auxiliary napkin.

With this type of auxiliary napkin, when removing it from the skin side of the sanitary napkin, the user can easily grasp the gap and pull the auxiliary napkin. This makes it easy to put on and take off the auxiliary napkin.

It is desirable that such an auxiliary napkin have no gap in the longitudinal direction between one end of the attachment portion and the other end of the auxiliary napkin.

With this type of auxiliary napkin, the attachment part provides a stronger engagement force, making it easier to more firmly secure the auxiliary napkin to the skin-side of the sanitary napkin. Therefore, even when the user walks or exercises while wearing the auxiliary napkin and sanitary napkin, the auxiliary napkin is less likely to shift out of position.

It is desirable that such an auxiliary napkin does not have the attachment portion in the center of the width direction.

With this type of auxiliary napkin, the stiffness in the widthwise center section is lower than the stiffness on both sides. As a result, when worn, the auxiliary napkin is prone to bending and deformation at the widthwise center section, which tends to deform into a roughly mountain-shaped shape that is convex in the thickness direction. This makes it easier for the auxiliary napkin to come into contact with the wearer's body, improving the fit and absorbing menstrual and other excretions more easily.

It is desirable that such a supplementary napkin have a folding guide line extending in the longitudinal direction at the center in the width direction.

With this type of auxiliary napkin, the folding guide lines create a crease in the auxiliary napkin, making it easier for it to bend convexly when worn, and the auxiliary napkin can be folded in half widthwise for compact packaging.

The auxiliary napkin comprises a liquid-absorbent body, a liquid-impermeable back sheet provided on the non-skin side of the absorbent body,
It is desirable that the

When using such an auxiliary napkin by placing it on top of a sanitary napkin, menstrual blood absorbed by the absorbent body of the auxiliary napkin is prevented from transferring to the absorbent body of the sanitary napkin. This makes it less likely for the absorbent body of the sanitary napkin to become soiled, allowing the sanitary napkin to last longer.

It is desirable that such an auxiliary napkin be attached by adhering the adhesive portion of the entire width of the unused sanitary napkin and a 50 mm area in the longitudinal direction of the sanitary napkin to a test cotton attachment conforming to JIS L 0803, and then attaching it to the skin-side of the sanitary napkin such that the average force required to peel the sanitary napkin from the test cotton attachment along the longitudinal direction of the sanitary napkin is 2.02 N or more and 4.53 N or less.

This type of auxiliary napkin makes it possible to create an auxiliary napkin that is easy to put on and take off compared to the multiple types of sanitary napkins available on the market.

Also, there is a napkin set comprising a sanitary napkin and an auxiliary napkin that is attached to the skin side of the sanitary napkin, wherein the non-skin side of the auxiliary napkin has an attachment section for attaching the auxiliary napkin to the skin side of the sanitary napkin, and the non-skin side of the sanitary napkin has an adhesive section for fixing the sanitary napkin to the user's underwear, and the entire area of the attachment section in an unused state is attached to the skin side of a second auxiliary napkin that has the same configuration as the auxiliary napkin. A napkin set is revealed in which the average magnitude of force required when peeling the auxiliary napkin from the second auxiliary napkin along the longitudinal direction of the auxiliary napkin after attaching it to the side is equal to or greater than the average magnitude of force required when peeling the sanitary napkin from the second auxiliary napkin along the longitudinal direction of the sanitary napkin after adhering the entire widthwise and a 50 mm longitudinal area of the adhesive portion of the unused second auxiliary napkin to the skin-side surface of the second auxiliary napkin.

With this type of napkin set, the auxiliary napkin can be removed from the sanitary napkin by pulling the auxiliary napkin while holding down the sanitary napkin. On the other hand, the sanitary napkin can be removed together with the auxiliary napkin by pulling the auxiliary napkin without holding down the sanitary napkin. This allows the user to easily change the auxiliary napkin and sanitary napkin.

====Embodiment====
<Basic configuration of auxiliary napkin 1>
This paper describes an auxiliary napkin 1, which is used as a feminine hygiene product by placing it on top of a sanitary napkin. Figure 1 is a schematic plan view showing the auxiliary napkin 1 as viewed from the skin side and the non-skin side. Figure 2 is a schematic cross-sectional view taken along line A-A in Figure 1.

The auxiliary napkin 1 is a so-called flat-type napkin that is roughly oval in plan view and has a longitudinal direction, width direction, and thickness direction that are perpendicular to one another. The longitudinal direction is the direction along the longitudinal direction of the auxiliary napkin 1, and the width direction is the direction along the lateral direction of the auxiliary napkin 1. In addition, in the thickness direction, the side that comes into contact with the wearer's body is called the skin side, and the opposite side is called the non-skin side.

As shown in Figure 2, the auxiliary napkin 1 comprises an absorbent body 10, a top sheet 11 arranged on the skin side of the absorbent body 10, an intermediate sheet 12 arranged between the absorbent body 10 and the top sheet 11, side sheets 13 arranged on the non-skin side of the absorbent body 10 so as to extend outward on both sides in the width direction, and a back sheet 14 arranged on the non-skin side of the absorbent body 10 and the side sheets 13. Adjacent materials in the thickness direction are joined to each other with an adhesive such as a hot melt adhesive.

The absorbent body 10 contains a polymeric absorbent (super absorbent polymer, also known as "SAP") and liquid-absorbent fibers such as pulp fibers. In this embodiment, it is formed in a generally oval shape elongated in the longitudinal direction, as indicated by the dashed line in Figure 1. The liquid-absorbent fibers (absorbent core) containing SAP may be covered with a liquid-permeable core wrap sheet (not shown). The configuration of the absorbent body 10 is not limited to the above, and examples include an SAP sheet in which an SAP layer is attached to a hydrophilic sheet, and an airlaid sheet in which liquid-absorbent fibers are formed into a sheet using an airlaid method.

The top sheet 11 is a liquid-permeable sheet member that is positioned closest to the wearer's skin in the thickness direction of the auxiliary napkin 1, and is the member that comes into direct contact with the wearer's skin when the auxiliary napkin 1 is in use. Therefore, it is desirable that the top sheet 11 be as flexible as possible and soft against the wearer's skin. Examples of sheet members that make up the top sheet 11 of this embodiment include air-through nonwoven fabrics. Furthermore, as shown in Figure 2, the top sheet 11 of this embodiment is positioned so as to cover the absorbent body 10 from the skin side, with both widthwise edge portions folded into the non-skin side of the absorbent body 10.

The intermediate sheet 12 is a liquid-permeable sheet member disposed between the absorbent body 10 and the top sheet 11 in the thickness direction of the auxiliary napkin 1. Examples of sheet members constituting the intermediate sheet 12 include spunbond nonwoven fabric, airlaid nonwoven fabric, tissue, and air-through nonwoven fabric. Note that the intermediate sheet 12 does not necessarily have to be provided.

The side sheets 13 are components that make up both widthwise ends of the skin-facing side of the auxiliary napkin 1. Because the side sheets 13 are likely to come into direct contact with the wearer's skin when the auxiliary napkin 1 is worn, it is desirable that they be as flexible as possible, similar to the top sheet 11. Examples of sheet components that make up the side sheets 13 in this embodiment include air-through nonwoven fabrics.

The backsheet 14 is a liquid-impermeable, breathable sheet member that is positioned on the non-skin side of the absorbent body 10 in the thickness direction of the auxiliary napkin 1. The provision of this backsheet 14 prevents liquids such as menstrual blood absorbed by the absorbent body 10 from penetrating from the skin side to the non-skin side. Therefore, when the auxiliary napkin 1 is used by placing it on the skin side of a sanitary napkin, menstrual blood absorbed by the auxiliary napkin 1 can be prevented from penetrating into the non-skin side of the sanitary napkin. Examples of sheet members that make up the backsheet 14 in this embodiment include resin films such as polyethylene and polypropylene.

The backsheet 14 also has an attachment section 31 on its non-skin side for attaching the auxiliary napkin 1 to the skin side of the sanitary napkin. In this embodiment, as shown in FIG. 1, the attachment section 31 is a pair of strip-shaped regions arranged side by side on the left and right sides of a widthwise center position CI along the longitudinal direction, and the non-skin side of the auxiliary napkin 1 is removably fixed to the skin side of the sanitary napkin via the attachment section 31. The structure and function of the attachment section 31 will be described in detail later.

<Basic structure of sanitary napkin 2>
Next, a sanitary napkin 2 will be described as an example of a sanitary napkin to which the auxiliary napkin 1 can be attached. The auxiliary napkin 1 of this embodiment can be attached to any commercially available sanitary napkin (including the sanitary napkin 2) that meets the specified conditions described herein.

Figure 3 is a schematic plan view showing the sanitary napkin 2 as viewed from the skin side and the non-skin side. Figure 4 is a schematic cross-sectional view taken along line B-B in Figure 3. In Figure 3, the sanitary napkin 2 has a longitudinal direction, a width direction, and a thickness direction, which are perpendicular to one another. The longitudinal direction is the direction along the longitudinal direction of the sanitary napkin 2, and the width direction is the direction along the lateral direction of the sanitary napkin 2. In this embodiment, the longitudinal direction of the sanitary napkin 2 (see Figure 3) and the longitudinal direction of the auxiliary napkin 1 (see Figure 1) correspond to each other. Therefore, hereinafter, both directions will be simply referred to as the "longitudinal direction," and will be distinguished as necessary by referring to them as the "longitudinal direction of the sanitary napkin 2." The same applies to the "thickness direction" and "width direction."

The sanitary napkin 2 comprises an absorbent body 20, a top sheet 21, the top sheet 21 positioned on the skin side of the absorbent body 20, a second sheet 22 positioned between the absorbent body 20 and the top sheet 21, side flaps 23 positioned on the skin side of the absorbent body 20 so as to extend outward in the width direction, and a back sheet 24 positioned on the non-skin side of the absorbent body 20 and the side flaps 23. Adjacent materials in the thickness direction are joined to each other with an adhesive such as a hot melt adhesive. The sanitary napkin 2 also comprises a napkin body 2C provided with the absorbent body 20, and a pair of wing portions 2W extending outward in the width direction from the longitudinal central region of the napkin body 2C (see Figure 3). However, the sanitary napkin 2 does not necessarily have to comprise the wing portions 2W.

The absorbent body 20, top sheet 21, second sheet 22, side flaps 23, and back sheet 24 of the sanitary napkin 2 have substantially the same functions and structures as the absorbent body 10, top sheet 11, intermediate sheet 12, side sheets 13, and back sheet 14 of the auxiliary napkin 1, respectively, and therefore detailed description will be omitted here.

The non-skin side of the napkin body 2C in the thickness direction (the non-skin side of the backsheet 24) is provided with adhesive sections 41 formed by applying a suitable adhesive, such as a hot melt adhesive, to multiple strip-shaped areas along the longitudinal direction. When the sanitary napkin 2 is in use, the adhesive sections 41 are attached to the wearer's underwear, etc., thereby securing the sanitary napkin 2 to the underwear, etc.

Similarly, wing adhesive portions 42 are provided on the non-skin side of the wing portions 2W in the thickness direction (the non-skin side of the backsheet 24). When the sanitary napkin 2 is worn, the wing portions 2W are folded toward the non-skin side, and the wing adhesive portions 42 are attached to the non-skin side in the crotch area of underwear, etc., thereby preventing the sanitary napkin 2 from shifting position. Note that the shape, number, size, etc. of the adhesive portions 41 and wing adhesive portions 42 are not limited to those shown in Figure 3.

When individually packaged for distribution to the market as a product, the sanitary napkin 2 is folded longitudinally in thirds at a first fold F1 and a second fold F2 set at predetermined longitudinal positions. As shown in FIG. 3, the first fold F1 is formed along the width direction at the front longitudinal side (forward of the wing portions 2W). Similarly, the second fold F2 is formed along the width direction at the rear longitudinal side (backward of the wing portions 2W). The sanitary napkin 2 may have folds other than the first fold F1 and the second fold F2 (for example, a third fold).

<Usage of auxiliary napkin 1>
A specific usage mode when the auxiliary napkin 1 is attached to a sanitary napkin 2 will now be described. Fig. 5 is a schematic plan view showing the state in which the auxiliary napkin 1 is attached to the skin side of the sanitary napkin 2. Figs. 6A to 6C are perspective views illustrating how to put on and take off the auxiliary napkin 1. Note that when actually using the auxiliary napkin 1, it is often put on and taken off from a sanitary napkin 2 that has already been secured to the wearer's underwear. That is, the auxiliary napkin 1 is put on and taken off from a sanitary napkin 2 that has been deformed into a curved shape to fit the wearer's body shape, but for convenience of explanation, Figs. 5 and 6 show the auxiliary napkin 1 being put on and taken off from a sanitary napkin 2 in a flat state.

When using the auxiliary napkin 1, first align the longitudinal direction of the auxiliary napkin 1 with the longitudinal direction of the sanitary napkin 2, and place the non-skin side of the auxiliary napkin 1 over the skin side of the sanitary napkin 2. Then, press the attachment part 31 on the non-skin side of the auxiliary napkin 1 against the top sheet 21 of the sanitary napkin 2, applying pressure from the skin side to the non-skin side and securing them together. At this time, it is recommended to adjust the position of the auxiliary napkin 1 so that the longitudinal center position CL of the auxiliary napkin 1 is approximately the longitudinal center of the wing portions 2W of the sanitary napkin 2. Because the wing portions 2W of the sanitary napkin 2 are located longitudinally in the crotch area of the wearer, positioning the auxiliary napkin 1 based on the position of the wing portions 2W makes it easier for the auxiliary napkin 1 to abut against the wearer's excretory opening when worn, making it easier to absorb menstrual blood, etc.

In this embodiment, the attachment section 31 is configured with an adhesive surface formed by applying an adhesive to a predetermined area, or a combination of a hook-and-loop fastener with multiple locking projections (hooks) on the non-skin-side surface and an adhesive surface. When the attachment section 31 includes a hook-and-loop fastener, the locking projections on the non-skin-side surface are hooked onto the nonwoven fibers of the top sheet 21 on the skin-side surface of the sanitary napkin 2, thereby securing the non-skin-side surface of the auxiliary napkin 1 to the skin-side surface of the sanitary napkin 2. This allows the auxiliary napkin 1 to be easily attached and detached from the sanitary napkin 2. Furthermore, the hook-and-loop fastener's adhesive strength is not easily weakened even with repeated attachment and detachment, making it easy to adjust the position of the auxiliary napkin 1 when attaching it.

When the auxiliary napkin 1 is attached to the sanitary napkin 2 as shown in Figure 6A, the auxiliary napkin 1 mainly absorbs menstrual blood and other fluids excreted from the wearer's body, making the sanitary napkin 2 less likely to become soiled. After the auxiliary napkin 1 has absorbed a predetermined amount of menstrual blood, the auxiliary napkin 1 is removed from the sanitary napkin 2 and replaced with a new auxiliary napkin 1.

When removing the auxiliary napkin 1 from the sanitary napkin 2, for example, hold the front longitudinal edge of the sanitary napkin 2 with one hand, grab the front longitudinal edge of the auxiliary napkin 1 with the other hand, and pull it toward the rear as shown in Figure 6B to peel the attachment portion 31 from the top sheet 21 of the sanitary napkin 2. The auxiliary napkin 1 may also be removed by pulling it from one side to the other in the width direction. After removing the used auxiliary napkin 1, prepare a new auxiliary napkin 1 and attach it again to the skin-side surface of the sanitary napkin 2 as shown in Figure 6A.

Furthermore, in this embodiment, when changing the sanitary napkin 2 along with the auxiliary napkin 1, the auxiliary napkin 1 and the sanitary napkin 2 can be simultaneously peeled off, as shown in Figure 6C, by grasping only the auxiliary napkin 1 and pulling it longitudinally (widthwise) without holding down the sanitary napkin 2. In other words, it is possible to peel off the adhesive portion 41 of the sanitary napkin 2 from the underwear without peeling off the attachment portion 31 of the auxiliary napkin 1 from the top sheet 21 of the sanitary napkin 2. Below, we will explain the features of the attachment portion 31 of the auxiliary napkin 1 that enable this operation.

<Regarding peel strength of attachment portion 31>
In this embodiment, the peel strength of the attachment portion 31 is adjusted so that the force required to attach and peel the attachment portion 31 of the auxiliary napkin 1 from a predetermined cloth is equal to or greater than the force required to attach and peel the adhesive portion 41 of the sanitary napkin 2 from a predetermined cloth. In other words, by making the peel strength of the attachment portion 31 of the auxiliary napkin 1 equal to or greater than the peel strength of the adhesive portion 41 of the sanitary napkin 2, the sanitary napkin 2 and the auxiliary napkin 1 can be easily replaced.

Figure 7 is a diagram illustrating a method for evaluating the peel strength of the attachment portion 31 of the auxiliary napkin 1. Peel strength is evaluated using an airbag-type pressure machine 70 and a tensile tester (not shown).

The evaluation procedure involves first preparing a common attachment member S to compare the peel strength between the attachment portion 31 of the auxiliary napkin 1 and the adhesive portion 41 of the sanitary napkin 2. Next, the magnitude of the force required when attaching and peeling off the attachment portion 31 of the auxiliary napkin 1 to this attachment member S is measured and used as the peel strength of the attachment portion 31. Similarly, the magnitude of the force required when attaching and peeling off the adhesive portion 41 of the sanitary napkin 2 to the attachment member S is measured and used as the peel strength of the adhesive portion 41. The peel strength of the attachment portion 31 and the peel strength of the adhesive portion 41 are then compared.

A napkin (auxiliary napkin 1) having a similar configuration to auxiliary napkin 1 is used as the attachment member S. In the following description, the auxiliary napkin 1 used as the sample for measuring the peel strength of the attachment portion 31 will be referred to as the first auxiliary napkin 1A. The auxiliary napkin 1 used as the attachment member S will be referred to as the second auxiliary napkin 1B.

When measuring the peel strength of the attachment portion 31 of the auxiliary napkin 1, as shown in Figure 7, the first auxiliary napkin 1A is placed on a horizontal table with the side on which the attachment portion 31 is provided (the non-skin side in Figure 2) facing upward, to prevent wrinkles from forming on the surface. The attachment portion 31 of the first auxiliary napkin 1A must be unused, and the attachment portion 31 must not be touched throughout the measurement. Next, the second auxiliary napkin 1B is placed on top of the first auxiliary napkin 1A in the thickness direction, with the side on which the attachment portion 31 is provided (the non-skin side) facing upward. When the two are placed on top of each other, the longitudinal direction of the first auxiliary napkin 1A and the longitudinal direction of the second auxiliary napkin 1B are aligned. In other words, the first auxiliary napkin 1A is placed so that the entire non-skin side overlaps the entire skin side of the second auxiliary napkin 1B. As a result, the entire area of the attachment portion 31 of the first auxiliary napkin 1A abuts against the top sheet 11 of the second auxiliary napkin 1B, and the two are lightly engaged (attached) together.

Next, the air bag 72 is placed on the upper thickness side of the second auxiliary napkin 1B. At this time, it is recommended to place a spacer sheet P, such as release paper, between the attachment part 31 of the second auxiliary napkin 1B and the air bag 72. This spacer sheet P prevents the attachment part 31 of the second auxiliary napkin 1B from engaging (affixing) with the air bag 72. The air bag 72 is a rubber bag-shaped member measuring 120 mm x 230 mm, and by supplying compressed air inside, it is possible to apply a pressure of 20 mm to 300 mmHg to the sample.

Next, a fixing plate 71 is placed on top of the air bag 72 and fixed in place. In this state, compressed air is supplied to the air bag 72 and pressurized at a pressure of 300 mmHg for one minute. This applies a uniform compressive force in the thickness direction to the first auxiliary napkin 1A and second auxiliary napkin 1B between the fixing plate 71 (and air bag 72) and the base, firmly attaching the entire area of the attachment portion 31 of the first auxiliary napkin 1A (sample) to the top sheet 11 of the second auxiliary napkin 1B (attachment target S).

After the attachment portion 31 is attached to the attachment member S, the fixing plate 71 and airbag 72 are removed. Then, cloth tape is attached to the first auxiliary napkin 1A and the second auxiliary napkin 1B in predetermined positions, and gripping portions are formed for pulling using a tensile tester. After the gripping portions are formed, one side of the tensile tester's grip (not shown) grips the gripping portion of the second auxiliary napkin 1B (attachment member S), and the other side of the tensile tester's grip (not shown) grips the gripping portion of the first auxiliary napkin 1A (sample). At this time, the distance between the grips of the tensile tester (the distance between one side and the other) is 20 mm.

The first auxiliary napkin 1A and the second auxiliary napkin 1B are then pulled along the longitudinal direction of the first auxiliary napkin 1A at a speed of 300 m/min, and the average load (N) applied until the entire area of the attachment portion 31 of the first auxiliary napkin 1A peels off from the second auxiliary napkin 1B is measured. This measurement is performed on multiple different first auxiliary napkins 1A (e.g., five), and the average value is calculated to determine the peel strength of the attachment portion 31 in the longitudinal direction.

It is assumed that the auxiliary napkins 1 of this embodiment will be distributed on the market in a state where multiple napkins are packed in one package. Therefore, it is advisable to select a predetermined number (e.g., five) of auxiliary napkins 1 from the multiple auxiliary napkins 1, 1... packed in the same package as samples (specimens) to be evaluated, and perform the above-mentioned measurements on each sample. However, it is not necessary to select samples from the same package; for example, it is also possible to randomly select a predetermined number (e.g., five) of auxiliary napkins 1 from those contained in a cardboard box that packs multiple packages as samples.

Similarly, the average load (N) is measured when the first auxiliary napkin 1A and the second auxiliary napkin 1B are pulled along the width direction of the first auxiliary napkin 1A at a speed of 300 m/min, and the peel strength in the width direction of the attachment portion 31 is measured. This measurement is performed on multiple different first auxiliary napkins 1A (e.g., five), and the average value is calculated to be the peel strength in the width direction of the attachment portion 31.

Figure 8 is a table showing data measured on the peel strength of the first auxiliary napkin 1A relative to the second auxiliary napkin 1B. The peel strength of the first auxiliary napkin 1A was measured using 10 types of samples S1 to S10, each with a different attachment portion 31 structure.

Samples S1 to S5 use a commercially available hook-and-loop fastener (hook tape) in combination with an adhesive surface as the attachment portion 31. The hook tape has multiple hooks, each consisting of a post and a bulk, attached to a base film. The length of the umbrella portion in the longitudinal direction (MD cap diameter) is 240 μm, the length of the umbrella portion in the width direction (CD cap diameter) is 300 μm, the height of the post portion (pin height) is 100 μm, the base film thickness is 55 μm, the CD hook diameter is 150 μm, the hook basis weight is 60 g/m2, and the number of hook pins is 3500/25.4 mm square.

The adhesive surface is formed by applying a pressure-sensitive adhesive such as a hot melt adhesive (HMA) at different basis weights to different areas. The pressure-sensitive adhesive used to form the adhesive surface is a block copolymer SBS (styrene-butadiene-styrene copolymer) with physical properties of viscosity at 140°C, 2800 MPa·s at 160°C, and 1450 MPa·s at 180°C, and a softening point of 85°C.

For samples S1 to S5, the hook tape was placed 11 mm wide on each side, spaced 30 mm apart, over a 100 mm long area, and two 10 mm wide adhesive strips (total width 20 mm) were placed between the hook tapes while varying the adhesive basis weight, forming the attachment portion 31 (see Figure 8 for detailed conditions).

Samples S6 to S10 have an adhesive surface formed by applying a hot melt adhesive (HMA) or other adhesive to different areas at different basis weights as the attachment portion 31. The adhesive used to form the adhesive surface is the same as that used in samples S1 to S5. In samples S6 to S10, the attachment portion 31 is formed by applying the adhesive to two 10 mm wide adhesive surfaces (total width of 20 mm) over a 100 mm long range, with the adhesive basis weight varied (see Figure 8 for detailed conditions).

Samples S1 to S10 all share the same structure except for the attachment portion 31. Therefore, the configuration of the skin-facing side (top sheet 11) of the second auxiliary napkin 1B, to which the attachment portion 31 of the first auxiliary napkin 1A is attached, is also the same.

The top sheet 11 of the second auxiliary napkin 1B is a 0.4 mm thick air-through nonwoven fabric. Tensile tests showed that the tensile strength was 4.0 N/mm2 when stretched 5% in the machine direction (MD), with a maximum tensile strength of 17.2 N/mm2. When stretched 5% in the cross direction (CD), the tensile strength was 0.3 N/mm2, with a maximum tensile strength of 4.1 N/mm2. Tear tests showed that the maximum tear strength in the machine direction (MD) was 3.3 N/mm2, and the maximum tear strength in the cross direction (CD) was 2.7 N/mm2. The absorbent core used was made of softwood pulp, which was pulverized and laminated to a basis weight of 200 g/m2 and a thickness of 3 mm. The backing film was a non-breathable film with a basis weight of 25 g/m2.

The measurement results showed that the peel strength in the longitudinal direction of the first auxiliary napkin 1A (samples S1 to S10) was 2.95 N (sample S10) to 6.02 N (sample S1), and the peel strength in the width direction was 10.03 N (sample S5) to 17.19 N (sample S6).

Figure 9 is a diagram illustrating a method for evaluating the peel strength of the adhesive portion 41 of the sanitary napkin 2 relative to the second auxiliary napkin 1B. The peel strength of the adhesive portion 41 of the sanitary napkin 2 can be measured in substantially the same manner as the peel strength of the attachment portion 31 of the first auxiliary napkin 1A. When measuring the peel strength of the adhesive portion 41 of the sanitary napkin 2, a sample is first prepared by cutting the sanitary napkin 2 to a predetermined length in the longitudinal direction. As shown in Figure 5, the longitudinal length of the sanitary napkin 2 is longer than the longitudinal length of the second auxiliary napkin 1B (auxiliary napkin 1), so the peel strength is measured assuming both lengths are equal. In this embodiment, the sanitary napkin 2 is cut at a position 90 mm from one longitudinal end of the sanitary napkin 2. The wing portion 2W is also cut. Furthermore, if the sanitary napkin 2 being evaluated has so-called upright gathers or equivalent parts, measurements are performed after the elastic members of the upright gathers have been cut or otherwise removed to eliminate stress.

Then, the sanitary napkin 2 (sample) cut to a predetermined length is placed on a horizontal table with the side with the adhesive portion 41 (the side opposite to the skin in Figure 4) facing upward, as shown in Figure 9, to prevent wrinkles from forming on the surface. The adhesive portion 41 of the sanitary napkin 2 is unused, and is not touched throughout the measurement. Next, the second auxiliary napkin 1B is placed on top of the sanitary napkin 2 in the thickness direction, with the side with the attachment portion 31 (the side opposite to the skin) facing upward. When the two are placed on top of each other, the longitudinal direction of the sanitary napkin 2 and the second auxiliary napkin 1B are aligned. This brings the entire width of the adhesive portion 41 of the sanitary napkin 2, as well as a predetermined area in the longitudinal direction, into contact with the top sheet 11 of the second auxiliary napkin 1B, lightly engaging (affixing) them.

Then, an airbag 72 is placed on the upper side of the second auxiliary napkin 1B in the thickness direction, and a fixing plate 71 is placed on top of the airbag 72 to secure it in place. In this state, compressed air is supplied to the airbag 72, and it is pressurized at a pressure of 300 mmHg for one minute. This applies a uniform compressive force in the thickness direction to the sanitary napkin 2 and second auxiliary napkin 1B between the fixing plate 71 (and airbag 72) and the base, and the adhesive portion 41 of the sanitary napkin 2 (sample) is firmly attached to the top sheet 11 of the second auxiliary napkin 1B (attachment member S).

After the adhesive portion 41 is attached to the attachment member S, the fixing plate 71 and airbag 72 are removed, and cloth tape is attached to the sanitary napkin 2 and second auxiliary napkin 1B in the specified positions, forming gripping portions for pulling using a tensile tester. One gripping portion (not shown) of the tensile tester is then used to grip the gripping portion of the second auxiliary napkin 1B (attachment member S), and the other gripping portion (not shown) of the tensile tester is used to grip the gripping portion of the sanitary napkin 2 (sample). At this time, the distance between the gripping portions of the tensile tester (the distance between one side and the other) is 20 mm.

The sanitary napkin 2 and the second auxiliary napkin 1B are then pulled along the longitudinal direction of the sanitary napkin 2 at a speed of 300 m/min, and the average load (N) applied until a region of the adhesive portion 41 of the sanitary napkin 2 having a length of 50 mm in the longitudinal direction peels off from the second auxiliary napkin 1B is measured. This measurement is performed on multiple different sanitary napkins 2 (e.g., five), and the average load is calculated to determine the peel strength of the adhesive portion 41 in the longitudinal direction.

Similarly, the average load (N) is measured when the sanitary napkin 2 and the second auxiliary napkin 1B are pulled at a speed of 300 m/min along the width direction of the sanitary napkin 2B. This measurement is performed on multiple different sanitary napkins 2 (e.g., five), and the average load is calculated to determine the peel strength of the adhesive portion 41 in the width direction.

Figure 10 is a table showing data measured for the peel strength of sanitary napkin 2 relative to second auxiliary napkin 1B. Measurements were conducted using ten types of commercially available sanitary napkins, X1 to X10, described below, as samples of sanitary napkin 2. As a result, the peel strength in the longitudinal direction of sanitary napkin 2 (samples X1 to X10) was 1.04 N (sample X7) to 2.04 N (sample X3), and the peel strength in the width direction was 2.85 N (sample X7) to 6.20 N (sample X3).

From the results in Figures 8 and 10, it was confirmed that the peel strength in the longitudinal direction of the attachment portion 31 of the first auxiliary napkin 1A (2.95 N to 6.02 N) is equal to or greater than the peel strength in the longitudinal direction of the adhesive portion 41 of the sanitary napkin 2 (1.04 N to 2.04 N). Thus, in the auxiliary napkin 1 of this embodiment, the peel strength of the attachment portion 31 is adjusted so that the peel strength in the longitudinal direction of the attachment portion 31 is equal to or greater than the peel strength in the longitudinal direction of the adhesive portion 41. In other words, the average magnitude of force required when attaching the entire area of the attachment portion 31 of an unused first auxiliary napkin 1A to the skin-side surface of the second auxiliary napkin 1B and then peeling the first auxiliary napkin 1A from the second auxiliary napkin 1B along the longitudinal direction is equal to or greater than the average magnitude of force required when adhering the entire widthwise and a 50 mm longitudinal area of the adhesive portion 41 of an unused sanitary napkin 2 to the skin-side surface of the second auxiliary napkin 1B and then peeling the sanitary napkin 2 from the second auxiliary napkin 1B along the longitudinal direction of the sanitary napkin 2.

Therefore, after attaching the auxiliary napkin 1 to the skin side of the sanitary napkin 2, the sanitary napkin 2 can be removed from the underwear together with the auxiliary napkin 1 by pulling the auxiliary napkin 1 along its length.

With this configuration, if you want to change only the auxiliary napkin 1, you can remove just the auxiliary napkin 1 from the sanitary napkin 2 by pulling the auxiliary napkin 1 while holding down the sanitary napkin 2 (see Figure 6B). On the other hand, if you want to change the sanitary napkin 2 as well, you can remove the sanitary napkin 2 from the underwear together with the auxiliary napkin 1 by pulling the auxiliary napkin 1 without holding down the sanitary napkin 2 (see Figure 6C). This allows the user to easily change the auxiliary napkin 1 and the sanitary napkin 2.

In addition, because the peel strength of the attachment portion 31 of the auxiliary napkin 1 is equal to or greater than the peel strength of the adhesive portion 41 of the sanitary napkin 2, the auxiliary napkin 1 can be more firmly fixed to the sanitary napkin 2 compared to when the peel strength of the attachment portion 31 is weaker than the peel strength of the adhesive portion 41. Therefore, even if the user (wearer) moves their body significantly while wearing the auxiliary napkin 1 and sanitary napkin 2, the auxiliary napkin 1 is less likely to shift position relative to the sanitary napkin 2, making it easier to prevent leakage of menstrual blood, etc.

Similarly, the results of Figures 8 and 10 confirmed that the peel strength in the width direction of the attachment portion 31 of the first auxiliary napkin 1A (10.03 N to 17.19 N) was equal to or greater than the peel strength in the width direction of the adhesive portion 41 of the sanitary napkin 2 (2.85 N to 6.20 N). Thus, in the auxiliary napkin 1 of this embodiment, the peel strength of the attachment portion 31 is adjusted so that the peel strength in the width direction of the attachment portion 31 is equal to or greater than the peel strength in the width direction of the adhesive portion 41. In other words, the average force required to attach the entire attachment portion 31 of an unused first auxiliary napkin 1A to the skin-side surface of a second auxiliary napkin 1B and then peel the first auxiliary napkin 1A from the second auxiliary napkin 1B along the widthwise direction is equal to or greater than the average force required to attach the entire widthwise and a 50 mm longitudinal area of the adhesive portion 41 of an unused sanitary napkin 2 to the skin-side surface of the second auxiliary napkin 1B and then peel the sanitary napkin 2 from the second auxiliary napkin 1B along the widthwise direction of the sanitary napkin 2. Therefore, as described above, the auxiliary napkin 1 and sanitary napkin 2 can be easily replaced.

Furthermore, in this embodiment, the longitudinal length of the auxiliary napkin 1 is shorter than the longitudinal length of the sanitary napkin 2. Therefore, when the auxiliary napkin 1 is attached to the sanitary napkin 2 as shown in FIG. 5, the absorbent body 20 of the sanitary napkin 2 is positioned longitudinally outboard of the auxiliary napkin 1. Therefore, even if leakage occurs outside the auxiliary napkin 1 due to reasons such as the auxiliary napkin 1 being unable to absorb all of the menstrual blood, the leaked liquid is absorbed by the absorbent body 20 of the sanitary napkin 2, making it less likely to soil the wearer's underwear. Furthermore, because the sanitary napkin 2 to which the auxiliary napkin 1 is attached is larger (longer in the longitudinal direction), the process of putting on and taking off the auxiliary napkin 1 is easier, as described in FIG. 6. For example, when attaching the auxiliary napkin 1, the auxiliary napkin 1 can be prevented from protruding from the sanitary napkin 2 without precise longitudinal positioning. Furthermore, when removing the auxiliary napkin 1, the auxiliary napkin 1 that has absorbed menstrual blood is unlikely to come into contact with the wearer's underwear, so the user can easily remove it without having to exercise excessive caution. In this way, the auxiliary napkin 1 can be easily replaced.

Furthermore, the longitudinal length of the auxiliary napkin 1 is longer than the longitudinal distance between the first fold F1 and the second fold F2, which are the folds that form the sanitary napkins 2 when they are packaged (see Figure 5). With this configuration, when attaching the auxiliary napkin 1 to the sanitary napkin 2, the user can adjust the position of the auxiliary napkin 1 using the folds F1 and F2 as reference points. Specifically, the front longitudinal edge of the auxiliary napkin 1 is positioned forward of the first fold F1, and the rear longitudinal edge of the auxiliary napkin 1 is positioned behind the second fold F2. In other words, the auxiliary napkin 1 is positioned so that it straddles the first fold F1 and the second fold F2 in the longitudinal direction. This allows the auxiliary napkin 1 to be positioned appropriately on the skin-side surface of the sanitary napkin 2. This makes the attachment of the auxiliary napkin 1 easier.

It is also desirable that the color of the auxiliary napkin 1 is different from that of the sanitary napkin 2. At the very least, it is desirable that the color of the outer edge of the auxiliary napkin 1 (i.e., the outline of the auxiliary napkin 1) is different from the color of the skin-side surface of the sanitary napkin 2. When the auxiliary napkin 1 is attached to the sanitary napkin 2 as shown in Figure 5, if the color of the outer edge of the auxiliary napkin 1 is different from the color of the skin-side surface of the sanitary napkin 2, the outline of the auxiliary napkin 1 becomes easier to see. This makes it easier for the user to determine whether the attachment position of the auxiliary napkin 1 relative to the sanitary napkin 2 is correct. It also makes it easier to determine where to grab the auxiliary napkin 1 when removing it. This makes the attachment of the auxiliary napkin 1 easier. Note that "different" colors refer to a difference of three or more hues on the Ostwald color wheel.

Furthermore, it is desirable that the color of the absorbent body 10 of the auxiliary napkin 1 be a reddish color. Specifically, it is desirable that the color be within the range of hue numbers 4 to 9 on the Ostwald color wheel (the "orange" or "red" range). Because the absorbent body 10 of the auxiliary napkin 1 is primarily intended to absorb menstrual blood, making the color of the absorbent body 10 a reddish color has the effect of concealing the absorbed menstrual blood. This allows the user to dispose of the used auxiliary napkin 1 without worrying about being seen by others when replacing it.

It is also desirable that the attachment portion 31 of the auxiliary napkin 1 be detachable from the sanitary napkin 2. In other words, it is desirable that the attachment portion 31 be able to maintain sufficient adhesive strength even when the auxiliary napkin 1 is repeatedly attached and detached from the skin-side surface of the sanitary napkin 2. This configuration makes it easy to adjust the position of the auxiliary napkin 1 relative to the sanitary napkin 2. For example, if you want to change the attachment position after attaching the auxiliary napkin 1 to the skin-side surface of the sanitary napkin 2, you can remove the auxiliary napkin 1 from the sanitary napkin 2, change its position, and then reattach it, and the auxiliary napkin 1 will still be firmly fixed in place. This makes the process of attaching the auxiliary napkin 1 easier.

In this embodiment, the attachment portion 31 of the auxiliary napkin 1 may be configured to include a hook-and-loop fastener, making it easier to attach and detach from the sanitary napkin 2. If the attachment portion 31 were configured solely with an adhesive surface using an adhesive or the like, when the attachment portion 31 was attached to the sanitary napkin 2 and then peeled off, fibers of the nonwoven fabric or the like would adhere to the attachment portion 31 (adhesive surface), reducing the adhesive strength. In this case, it is often difficult to attach the attachment portion 31 to the sanitary napkin 2 multiple times. In particular, in this embodiment, it becomes difficult to remove the sanitary napkin 2 together with the auxiliary napkin 1. In contrast, if at least a portion of the attachment portion 31 is configured with a hook-and-loop fastener, the engagement strength (adhesion strength) of the hook-and-loop fastener portion is less likely to decrease, even after the attachment portion 31 is engaged with the skin-side surface of the sanitary napkin 2 and then peeled off. Therefore, the attachment portion 31 can be repeatedly attached and detached to and from the sanitary napkin 2 while satisfying the above-mentioned relationship (peel strength of the attachment portion 31 of the first auxiliary napkin 1A ≥ peel strength of the adhesive portion 41 of the sanitary napkin 2). This makes it easy to adjust the attachment position of the auxiliary napkin 1 relative to the sanitary napkin 2.

Figure 11 is a table showing the results of an investigation into changes in peel strength when the attachment part 31 of the auxiliary napkin 1 is repeatedly attached and detached. The repeated peel strength investigation was carried out as follows. First, sample S1 (hook tape + adhesive surface 40 g/m2) described in Figure 8 was prepared as the auxiliary napkin 1 for which repeated peel strength was to be measured. Then, a first peel strength measurement was carried out for sample S1 using the method described in Figure 7. Next, using sample S1 used for the first peel strength measurement, the peel strength was measured again (second measurement) using the method described in Figure 7. This operation was carried out multiple times (three times in this embodiment) to investigate how the peel strength changes when the attachment part 31 is repeatedly attached and detached.

As shown in Figure 11, when peel strength measurements were repeated three times using an auxiliary napkin 1 whose attachment portion 31 was constructed by combining hook tape (hook and loop fastener) and an adhesive surface, it was found that the peel strength gradually decreased due to the presence of the adhesive surface. However, even after three repeated attachment and detachment cycles, it was confirmed that the peel strength of the auxiliary napkin 1 (sample S1) remained stronger than the longitudinal peel strength (1.04 N to 2.04 N) and width peel strength (2.85 N to 6.20 N) of the adhesive portion 41 of the sanitary napkin 2. In other words, it was confirmed that at least the engagement force (bonding force) of the hook and loop fastener portion was maintained. Therefore, it is possible to repeatedly attach and detach the attachment portion 31 while maintaining the relationship "peel strength of the attachment portion 31 of the first auxiliary napkin 1A ≥ peel strength of the adhesive portion 41 of the sanitary napkin 2."

Since auxiliary napkins 1 are consumables, it is sufficient if the attachment part 31 can be attached and detached several times. Therefore, as long as the relationship "peel strength of the attachment part 31 of the first auxiliary napkin 1A (sample S1) ≥ peel strength of the adhesive part 41 of the sanitary napkin 2" is maintained over approximately three attachment and detachment operations, as in sample S1 in Figure 11, there will be no practical problem.

1, the attachment portion 31 is provided at a predetermined distance from the outer edge of the auxiliary napkin 1 in the longitudinal direction. In other words, a predetermined gap (distance) is provided between one end (e.g., the front) of the attachment portion 31 and one end (e.g., the front) of the auxiliary napkin 1 in the longitudinal direction. Because no adhesive force is applied by the attachment portion 31 in this gap, the non-skin side of the auxiliary napkin 1 and the skin side of the sanitary napkin 2 are not joined. In other words, even when the auxiliary napkin 1 is attached to the sanitary napkin 2, the non-skin side of the auxiliary napkin 1 floats in the thickness direction above the skin side of the sanitary napkin 2 in this gap. Therefore, when removing the auxiliary napkin 1 from the sanitary napkin 2, this gap serves as a "grip portion" of the auxiliary napkin 1, allowing the user to easily grasp this grip portion and pull the auxiliary napkin 1. This makes it easy to put on and take off the auxiliary napkin 1.

However, there does not need to be any gap between the attachment portion 31 and the outer edge of the auxiliary napkin 1 in the longitudinal direction. With this configuration, the engagement force of the attachment portion 31 is greater, making it easier to more firmly secure the auxiliary napkin 1 when attaching it to the skin-side surface of the sanitary napkin 2. This makes it less likely for the auxiliary napkin 1 to shift position even when the user walks or exercises while wearing the auxiliary napkin 1 and sanitary napkin 2.

Furthermore, as shown in FIG. 1, the auxiliary napkin 1 has a pair of attachment portions 31, 31 on both sides of the central position CI in the width direction. In other words, the attachment portion 31 is not provided in the central portion in the width direction. Therefore, in the auxiliary napkin 1 of this embodiment, the rigidity of the central portion in the width direction is lower than the rigidity of both side portions (portions where the attachment portions 31 are provided).

When a user (wearer) puts on the auxiliary napkin 1, the auxiliary napkin 1 typically undergoes three-dimensional deformation in accordance with the unevenness of the wearer's body shape. In the auxiliary napkin 1 of this embodiment, as described above, the stiffness of the widthwise center is lower than the stiffness of the opposite sides, so the auxiliary napkin 1 is prone to bending and deforming in the widthwise direction along the widthwise center position CI. Specifically, when put on, the auxiliary napkin 1 is prone to deforming at the widthwise center position CI into a roughly mountain-shaped shape that convexes toward the skin in the thickness direction. In this way, the widthwise center deforms convexly toward the skin, making it easier for the auxiliary napkin 1 to come into contact with the wearer's vagina, etc., improving the fit when put on and facilitating the absorption of excrement such as menstrual blood.

The auxiliary napkin 1 may be pre-creased by folding it widthwise at the widthwise center position CI. That is, the auxiliary napkin 1 may have a folding guide line extending longitudinally along the widthwise center position CI. Providing such a folding guide line (fold) makes it easier for the auxiliary napkin 1 to naturally deform convexly as described above when worn. Furthermore, by folding the auxiliary napkin 1 in half widthwise along the folding guide line and packaging it, the individual package of the auxiliary napkin 1 can be formed compactly. This makes it easier for the user to carry the auxiliary napkin 1 in a bag or the like, facilitating tasks such as changing just the auxiliary napkin 1 when using a restroom while out and about.

The auxiliary napkin 1 also has a liquid-impermeable back sheet 14 on the non-skin side of the absorbent body 10 in the thickness direction. Therefore, even when the absorbent body 10 absorbs menstrual blood, the back sheet 14 prevents the menstrual blood from migrating from the skin side to the non-skin side in the thickness direction. As a result, when the auxiliary napkin 1 is used overlapping the skin side of the sanitary napkin 2, menstrual blood absorbed by the absorbent body 10 of the auxiliary napkin 1 is prevented from migrating to the absorbent body 20 of the sanitary napkin 2. This makes it less likely for the absorbent body 20 of the sanitary napkin 2 to become soiled, allowing the sanitary napkin 2 to last longer.

<About the target sanitary napkin 2>
Here, we will explain the sanitary napkin 2 to which the auxiliary napkin 1 of this embodiment is attached. The auxiliary napkin 1 of this embodiment can be used with sanitary napkins 2 that have an adhesive portion 41 with a predetermined peel strength. Specifically, the entire width and a 50 mm longitudinal area of the unused adhesive portion 41 are attached to a test cotton attachment (Kanakin No. 3) conforming to JIS L 0803, and the sanitary napkin 2 can be peeled off from the test cotton attachment along the longitudinal direction of the sanitary napkin 2 with an average force of 2.02 N or more and 4.53 N or less.

Figure 12 is a diagram explaining the method for evaluating the peel strength of the adhesive portion 41 of the sanitary napkin 2. Figure 13 is a table showing the results of measuring the peel strength of the adhesive portion 41 for several types of sanitary napkins 2.

The peel strength of the adhesive portion 41 of the sanitary napkin 2 can be measured in a manner similar to the peel strength measurement method described in Figure 9. First, several types of commercially available sanitary napkins are prepared, and each is cut to a predetermined length (e.g., 90 mm) in the longitudinal direction to create a sample. In this embodiment, ten samples X1 to X10 of different types and sizes (lengths in the longitudinal direction) of the sanitary napkin 2 intended for use are prepared, and the peel strength of each is measured. The following describes the measurement of sample X1 as an example.

Cut a sanitary napkin 2 sample X1 to a specified length and place it on a horizontal table with the adhesive portion 41 facing upwards, taking care not to create wrinkles on the surface. The adhesive portion 41 of sample X1 should be unused, and should not be touched throughout the measurement.

Next, the attachment member S is placed on top of the thickness of sample X1. For the attachment member S, a cotton test cloth (also known as "Kanakin No. 3") conforming to JIS L 0803 is used. Details of Kanakin No. 3 are publicly known, so a detailed explanation will be omitted here.

Then, the airbag 72 is placed above the attachment member S (Kanakin No. 3) in the thickness direction, and the fixing plate 71 is placed on top of the airbag 72 and fixed in place. In this state, compressed air is supplied to the airbag 72 and pressurized at a pressure of 300 mmHg for one minute. This applies a uniform compressive force in the thickness direction to the sample X1 and attachment member S between the fixing plate 71 (and airbag 72) and the base, firmly adhering the adhesive portion 41 of the sample X1 to the attachment member S.

After the adhesive portion 41 is attached to the workpiece S, the fixing plate 71 and airbag 72 are removed, and cloth tape is attached to the sample X1 and workpiece S at predetermined positions to form gripping portions for pulling using a tensile tester. The gripping portion of the workpiece S is then gripped with a grip on one side of the tensile tester (not shown), and the gripping portion of the sample X1 is gripped with a grip on the other side of the tensile tester (not shown). At this time, the distance between the gripping portions of the tensile tester (the distance between one side and the other side) is 20 mm.

Then, the two are pulled along the longitudinal direction of sample X1 (sanitary napkin 2) at a speed of 300 m/min, and the average load (N) applied until a 50 mm long region of the adhesive portion 41 of sample X1 in the longitudinal direction peels off from the attachment member S is measured. Similar measurements are performed multiple times (for example, five times), and the average load is calculated to determine the peel strength of the adhesive portion 41 in the longitudinal direction.

The peel strength of the adhesive portion 41 was measured in this manner for each of samples X1 to X10, yielding the data shown in Figure 13. In Figure 13, the length (mm) represents the longitudinal length of each sanitary napkin 2 before cutting (napkin size), and the average load (N) represents the peel strength of each sanitary napkin 2 obtained by the above measurement. As a result, the maximum peel strength of the adhesive portion 41 was 2.02 N (sample X4), and the minimum was 4.53 N (sample X3).

For each of the sanitary napkins 2 corresponding to samples X1 to X10, the peel strength of the adhesive portion 41 described in Figures 7 to 10 was compared with the peel strength of the attachment portion 31 of the auxiliary napkin 1, and the peel strength of the attachment portion 31 was adjusted so that in each case the peel strength of the attachment portion 31 was equal to or greater than the peel strength of the adhesive portion 41. As a result, when the auxiliary napkin 1 is attached to and used with a sanitary napkin 2 having a peel strength of at least 2.02 N or more and 4.53 N or less, the relationship between the peel strength of the adhesive portion 41 and the peel strength of the attachment portion 31 described above can be satisfied. In other words, an auxiliary napkin 1 that allows for easy replacement of the sanitary napkin 2 and the auxiliary napkin 1 can be realized.
===Other Embodiments===

The above describes an embodiment of the present invention. However, the above embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. Furthermore, the present invention may be modified or improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof.

1 supplementary napkin,
1A First auxiliary napkin, 1B Second auxiliary napkin (attached member),
2. Sanitary napkins,
2C napkin body, 2W wing,
10 absorbent body,
11 top sheet, 12 intermediate sheet, 13 side sheet, 14 back sheet,
20 absorbent body,
21 Top sheet, 22 Second sheet, 23 Side flap,
24 back seat,
31 mounting portion,
41 adhesive portion, 42 wing adhesive portion,
70 Air bag type pressurizer, 71 Fixing plate, 72 Air bag,
F1: First fold, F2: Second fold,
S Attached member

Claims (13)

A napkin set comprising a sanitary napkin and an auxiliary napkin attached to the skin side of the sanitary napkin,
The auxiliary napkin has an absorbent body and a liquid-impermeable backsheet disposed closer to the skin than the absorbent body,
the backsheet has an attachment portion on its non-skin side for attaching the auxiliary napkin to the skin side of the sanitary napkin;
The non-skin side of the sanitary napkin is provided with an adhesive portion for fixing the sanitary napkin to a user's underwear,
The entire area of the attachment portion in an unused state is attached to the skin side of a second auxiliary napkin having the same structure as the auxiliary napkin, and then the average magnitude of the force applied when peeling the auxiliary napkin from the second auxiliary napkin along the longitudinal direction of the auxiliary napkin is:
the adhesive portion in an unused state is attached to the skin-side surface of the second auxiliary napkin over the entire width direction and over a 50 mm area in the longitudinal direction, and then the force required to peel the sanitary napkin from the second auxiliary napkin along the longitudinal direction of the sanitary napkin is equal to or greater than the average force required;
The back sheet is configured to prevent menstrual blood from moving from the skin side to the non-skin side,
The napkin set is configured so that the auxiliary napkin can be removed from the sanitary napkin by pulling the auxiliary napkin while holding down the sanitary napkin, and so that the sanitary napkin can be removed together with the auxiliary napkin by pulling the auxiliary napkin without holding down the sanitary napkin. 2. The napkin set according to claim 1,
The average magnitude of the force applied when attaching the entire area of the attachment portion in an unused state to the skin side of the second auxiliary napkin and then peeling the auxiliary napkin from the second auxiliary napkin along the width direction is:
A napkin set characterized in that the adhesive portion in an unused state, the entire width and a 50 mm area in the longitudinal direction, is attached to the skin side of the second auxiliary napkin, and then the force applied when peeling the sanitary napkin from the second auxiliary napkin along the width direction of the sanitary napkin is greater than the average value. The napkin set according to claim 1 or 2,
The length of the auxiliary napkin in the longitudinal direction is
The napkin set is characterized in that the length in the longitudinal direction is shorter than that of the sanitary napkin. The napkin set according to any one of claims 1 to 3,
The sanitary napkin has a first fold and a second fold, which are to be folded when the sanitary napkin is packed, and which are provided at different positions in the longitudinal direction of the sanitary napkin,
The length of the auxiliary napkin in the longitudinal direction is
The napkin set is characterized in that the distance between the first fold and the second fold is longer than the distance in the longitudinal direction of the sanitary napkin. The napkin set according to any one of claims 1 to 4,
The napkin set is characterized in that the sanitary napkin and the auxiliary napkin are different in color. The napkin set according to any one of claims 1 to 5,
The napkin set is characterized in that the color of the auxiliary napkins is a color included in the range of hue numbers 4 to 9 on the Ostwald color wheel. The napkin set according to any one of claims 1 to 6,
The napkin set is characterized in that the attachment portion is detachable from the skin side of the sanitary napkin. The napkin set according to claim 7,
The napkin set is characterized in that the attachment portion is configured to include a hook-and-loop fastener. The napkin set according to any one of claims 1 to 8,
The napkin set is characterized in that a predetermined gap is provided between one end of the attachment portion and one end of the auxiliary napkin in the longitudinal direction. The napkin set according to any one of claims 1 to 8,
The napkin set is characterized in that no gap is provided between one end of the attachment portion and one end of the auxiliary napkin in the longitudinal direction. The napkin set according to any one of claims 1 to 10,
The napkin set is characterized in that the attachment portion is not provided in the central portion in the width direction. The napkin set according to claim 11,
A napkin set characterized in that a folding guide line extending in the longitudinal direction is provided in the central portion in the width direction. The napkin set according to any one of claims 1 to 12,
A napkin set characterized in that the adhesive portion of an unused sanitary napkin is attached to a test cotton attachment conforming to JIS L 0803 over the entire width of the sanitary napkin and over a 50 mm area in the longitudinal direction of the sanitary napkin, and then attached to the skin side of the sanitary napkin such that the average force applied when peeling the sanitary napkin from the test cotton attachment along the longitudinal direction of the sanitary napkin is 2.02 N or more and 4.53 N or less.