JP2008168079A - Sanitary napkin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sanitary napkin effectively suppressing the leak of menstrual blood even when the menstrual blood is repetitively discharged to a center part. <P>SOLUTION: An absorbent body 13 is formed to allow the density of a polymer absorber in the center part R1 to be smaller than the density of the polymer absorber in a peripheral part R2. Consequently, the leak of the menstrual blood is effectively suppressed even when the menstrual blood is repetitively discharged. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sanitary napkin in which an absorbent body has a central portion and a peripheral portion surrounding the central portion, and the thickness of the central portion of the absorbent body is larger than the thickness of the peripheral portion.

Conventionally, the thickness of the absorbent body at the center where the menstrual blood discharge site abuts is larger than the thickness of the absorber at the peripheral portion, thereby improving the fit to the menstrual blood discharge site and increasing the height in the central portion. A sanitary napkin is known in which the amount of menstrual blood absorbable in the central part is increased by increasing the ratio of the molecular absorbent (ratio of the polymeric absorbent in the absorbent) to the ratio of the polymeric absorbent in the periphery. (See Patent Documents 1 and 2).
Japanese Utility Model Publication No. 64-925 Japanese Patent Publication No. 6-93903

  In general, menstrual blood absorbed by the absorbent body is instantaneously absorbed by the voids of the hydrophilic fiber and then gradually absorbed by the polymer absorbent body. As a result, the volume of the polymer absorbent body expands. However, in the conventional sanitary napkin, the ratio of the polymer absorbent in the central part is higher than the ratio of the polymer absorbent in the peripheral part, so that menstrual blood absorbed in the central part cannot diffuse to the peripheral part. . Furthermore, the higher the ratio of the polymer absorbent in the central part is higher than the ratio of the polymer absorbent in the peripheral part, the voids of the hydrophilic fibers disappear when the polymer absorbent expands by absorbing menstrual blood. There is no space to absorb blood. Therefore, according to the conventional sanitary napkin, when menstrual blood is repeatedly discharged to the central part, the liquid permeability in the central part is significantly reduced due to blocking of menstrual blood in the central part or swelling of the polymer absorber. As a result, menstrual blood can no longer be absorbed in the central portion, and there is a risk that menstrual blood leaks due to overflowing menstrual blood passing through the body or flowing on the product surface.

  The present invention has been made to solve the above-described problems, and its purpose is to provide a physiological use that can effectively suppress the occurrence of menstrual leakage even when menstrual blood is repeatedly discharged to the central portion. To provide a napkin.

  The inventors of the present invention have conducted extensive research and, as a result, formed the absorber so that the density of the polymer absorber in the central portion is smaller than the density of the polymer absorber in the peripheral portion. It has been found that the occurrence of menstrual leakage can be effectively suppressed even when blood is repeatedly discharged to the center.

  Hereinafter, a configuration of a sanitary napkin according to an embodiment of the present invention will be described with reference to the drawings. In addition, this invention is not limited to a sanitary napkin, It can apply to absorbent articles for women, such as a panty liner and an incontinence pad.

[Configuration of sanitary napkin]
A sanitary napkin 1 according to an embodiment of the present invention is used by a woman during menstruation wearing the inner surface of an undergarment. As shown in FIG. 1, the planar shape of the sanitary napkin 1 has a front edge portion 2 and a rear edge portion 3 that are substantially arc-shaped, and is wider in the width direction (X on the rear edge portion 3 side than the front edge portion 2 side). (Direction) is longer. The left edge portion 4 and the right edge portion 5 have a curved shape, and the distance between the left edge portion 4 and the right edge portion 5, that is, the width dimension of the sanitary napkin 1 abuts mainly on the crotch portion of the wearer. The rear edge 3 side that mainly abuts on the collar is larger than the front edge 2 side. The left edge 4 and the right edge 5 protrude in the width direction at a position that is biased toward the front edge 2 relative to the center line that bisects the sanitary napkin 1 in the front-rear direction. 7 is formed. As shown in FIG. 2, the sanitary napkin 1 is provided with a back sheet 11 that comes into contact with the inner surface of the undergarment and a top sheet 12 that comes into contact with the wearer's skin. Both the back sheet 11 and the top sheet 12 have the same shape as that of the sanitary napkin 1, that is, the front edge 2, the rear edge 3, the left edge 4, and the right edge 5, and the wings 6, 7 It is the shape which forms.

  An absorber 13 is provided on the back sheet 11. In this sanitary napkin 1, the absorbent body 13 has a vertically long central portion R1 extending in the front-rear direction as shown in FIG. 3 and a peripheral portion R2 surrounding the central portion R1, and as shown in FIG. The portion R1 has a shape that protrudes to the top sheet 12 side than the peripheral portion R2. Moreover, the pressing groove 8 (refer FIG. 1) is formed in the surface of the top sheet 12 corresponding to center part R1 so that center part R1 may be enclosed. In this pressing groove 8, the top sheet 12 and the absorber 13 are heat-pressed, the absorber 13 is crushed, and the top sheet 12 is concave on the surface of the crushed portion. According to this pressing groove 8, menstrual blood is collected in the pressing groove 8 directly surrounding the central portion R1, and the collected menstrual blood is transmitted to the surrounding pressing groove 8, thereby more efficiently absorbing menstrual blood. Occurrence of menstrual leakage can be suppressed. An intermediate (second) sheet such as a sheet in which grooves are formed in the width direction or the length direction is interposed between the top sheet 12 and the absorber 13, and the menstrual blood in the width direction and the length direction is provided by the intermediate sheet. Menstrual blood may be absorbed more efficiently by promoting the diffusion of blood. Moreover, in the area | region of the outer side of the absorber 13, the back sheet 11 and the top sheet 12 are adhere | attached with the hot-melt-adhesive.

  The back sheet 11 is liquid-blocking and is made of, for example, low density polyethylene (LDPE). The top sheet 12 is liquid permeable, and is formed of any combination of a liquid permeable nonwoven fabric, a nonwoven fabric having a large number of liquid permeable holes, and a resin film having a large number of liquid permeable holes. . The absorbent body 13 has a configuration in which a mixture of hydrophilic pulp fibers and superabsorbent resin (hereinafter referred to as SAP) is wrapped with tissue, and the back sheet 11 side surface (back surface) is as shown in FIG. A mesh-like embossing 21 is applied. As will be described in detail later, the absorber 13 is formed such that the density of the polymer absorber in the central portion R1 is smaller than the density of the polymer absorber in the peripheral portion R2.

[Method for producing sanitary napkin]
The sanitary napkin 1 is manufactured by using a manufacturing system as shown in FIG. In the manufacturing system shown in FIG. 4, first, a strip-shaped tissue 33 is supplied from the tissue roll 31 to the pattern plate drum 32. As shown in FIG. 5, concave portions 51 and 52 having the same shape as the central portion R1 and the peripheral portion R2 of the absorber 13 are periodically formed in the circumferential direction on the outer peripheral portion of the pattern plate drum 32. The pulp fiber and SAP are respectively supplied to 51 and 52 from the pulp fiber supply device 35 and the SAP feeder 36, and the pattern plate drum 32 is rotated in accordance with the supply speed of the tissue 32, whereby the absorber 13 is formed on the tissue 32. The mixture of pulp fiber and SAP to be patterned is patterned.

  Next, the mixed body patterned by winding the width direction side edge part of the tissue 33 inside by the tissue winding roller 40 is wrapped with the tissue 33 to form an absorbent body. Next, embossing is performed on both the front surface (top sheet 12 side surface) and the back surface (back sheet 11 side surface) of the absorbent body 13 using the absorbent body embossing apparatus 41. A mesh pattern 61 as shown in FIG. 6 is patterned on the outer peripheral portion of the upper roller 41a of the absorber embossing device 41, and the lower roller 41b is the same as the central portion R1 of the absorber 13 as shown in FIG. Shaped concave portions 62 are periodically formed. Thereby, the convex part and mesh-like embossing 21 which correspond to center part R1 are formed in the surface and the back surface of the absorber 13, respectively.

  Next, after separating the continuous absorber individually by cutting the front and back of the absorber using the absorber front / rear cutter 42, each of the top sheets 12 supplied from the top sheet roll 43 is replaced with a hot melt adhesive. Adhere to the surface of the absorber. Next, the top sheet 12 and the absorber 13 are heated and pressure-bonded using the hinge device 45 to form the compressed groove 8, and then the back sheet 11 supplied from the back sheet roll 46 is absorbed by the hot melt adhesive. Adhere to the back of the body. Finally, a series of manufacturing steps of the sanitary napkin 1 is completed by cutting the back sheet 11 and the top sheet 12 into the shape shown in FIG.

〔Example〕
Hereinafter, the absorber which concerns on this invention is demonstrated in detail based on an Example. In the absorbers shown in Examples 1 to 7 below, the density of the superabsorbent resin (SAP) in the central portion R1 (hereinafter referred to as SAP density) is smaller than the SAP density in the peripheral portion R2. In the absorbers shown in Comparative Examples 1 to 3, the SAP density in the central portion R1 is greater than or equal to the SAP density in the peripheral portion R2, as in the conventional absorber. In addition, in this specification, SAP density means the weight of SAP contained per unit volume of the absorber which consists of a pulp fiber, SAP, and tissue.

[Example 1]
In Example 1, as shown in Table 1 below, SAP density at the central portion R1 and the peripheral portion R2 is respectively formed an absorber so as to 0.042 g / cm ₃ and 0.167 g / cm _3.

[Example 2]
In Example 2, as shown in Table 1 below, the absorber was formed so that the SAP densities in the central portion R1 and the peripheral portion R2 were 0.017 g / cm ₃ and 0.067 g / cm ₃ , respectively.

Example 3
In Example 3, as shown in Table 1 below, the absorber was formed so that the SAP densities in the central portion R1 and the peripheral portion R2 were 0.033 g / cm ₃ and 0.133 g / cm ₃ , respectively.

Example 4
In Example 4, as shown in Table 1 below, the absorber was formed so that the SAP densities in the central portion R1 and the peripheral portion R2 were 0.067 g / cm ₃ and 0.267 g / cm ₃ , respectively.

Example 5
In Example 5, as shown in Table 1 below, the absorber was formed so that the SAP densities in the central portion R1 and the peripheral portion R2 were 0.100 g / cm ₃ and 0.400 g / cm ₃ , respectively.

Example 6
In Example 6, as shown in Table 1 below, the absorber was formed so that the SAP densities in the central portion R1 and the peripheral portion R2 were 0.133 g / cm ₃ and 0.533 g / cm ₃ , respectively.

Example 7
In Example 7, as shown in Table 1 below, SAP density at the central portion R1 and the peripheral portion R2 is respectively formed an absorber so as to 0.167 g / cm ₃ and 0.667 g / cm _3.

[Comparative Example 1]
In Comparative Example 1, as shown in Table 1 below, SAP density at the central portion R1 and the peripheral portion R2 is respectively formed an absorber so as to 0.167 g / cm ₃ and 0.043 g / cm _3.

[Comparative Example 2]
In Comparative Example 2, as shown in Table 1 below, the absorber was formed so that the SAP densities in the central portion R1 and the peripheral portion R2 were 0.042 g / cm ₃ and 0.043 g / cm ₃ , respectively.

[Comparative Example 3]
In Comparative Example 3, as shown in Table 1 below, the absorber was formed so that the SAP density in the central portion R1 and the peripheral portion R2 were both 0.167 g / cm ₃ .

[Penetration time]
For the absorbers of Examples 1 to 7 and Comparative Examples 1 to 3, the permeation time (seconds) of artificial menstrual blood when quantitative artificial menstrual blood was injected by the following method was measured. First, an acrylic plate with holes is placed on the sample with the nonwoven fabric on the surface of the absorbent, and artificial menstrual blood is applied to the sample through the holes in the acrylic plate using an autoburette (injection rate 96 ml / min). 7 ml was injected. The acrylic plate was overlaid on the sample so that the hole was positioned at the central portion R1. Then, the time from the start of injecting artificial menstrual blood to the completion of infiltration of artificial menstrual blood was measured as the first infiltration time (second). The time when the penetration of artificial menstrual blood was completed was the time when artificial menstrual blood disappeared from the nonwoven fabric and around the hole in the acrylic plate.

  Next, after the permeation of artificial menstrual blood was completed, the sample was left for 3 minutes, and then 7 ml of artificial menstrual blood was injected into the sample through the hole of the acrylic plate again using an autoburette (injection speed 96 ml / min). Then, the time from the start of injecting artificial menstrual blood to the completion of infiltration of artificial menstrual blood was measured as the second infiltration time (second).

  Furthermore, after the permeation of artificial menstrual blood was completed, it was left for 3 minutes, and then 7 ml of artificial menstrual blood was injected into the sample through a hole in the acrylic plate using an autoburette (injection speed 96 ml / min). The time from the start of injecting artificial menstrual blood to the completion of the penetration of artificial menstrual blood was measured as the third infiltration time (seconds). The measurement results are shown in FIG.

[Rewet evaluation]
About the absorber of Examples 1-7 and Comparative Examples 1-3, the rewet (reverse performance) of center part R1 and peripheral part R2 after artificial menstrual blood absorption was evaluated with the following method. First, a sample in which a nonwoven fabric is stacked on the surface of an absorbent body is placed on a flat acrylic plate, and then an acrylic plate (thickness 5 mm) having a hole is stacked on the sample, and an autoburette (injection speed 10 g / min) is placed. ) Was used to drop 10 g (1 minute) of artificial menstrual blood to the sample through the hole in the acrylic plate. In addition, the acrylic board was piled up on the sample so that the position of a hole might be located in a rewet evaluation object site | part (central part R1 or peripheral part R2).

Next, after the dropping of the artificial menstrual blood was completed, it was left for 3 minutes, and then the acrylic plate with holes was removed, and 10 filter papers with a weight A determined in advance were placed on the sample. Next, after placing an acrylic plate on the filter paper, a weight with a load on the sample of 100 g / cm ₂ was placed on the acrylic plate. Then, the weight B of the filter paper after 3 minutes from the placement of the weight was measured, and the rewetting was evaluated by substituting the weights A and B into the following Equation 1. The evaluation results are shown in FIG.

[Diffusion performance evaluation]
About the absorber of Examples 1-7 and Comparative Examples 1-3, the diffusion area and maximum diffusion length of the surface and back surface after artificial menstrual blood absorption were evaluated with the following method. First, after a sample in which a nonwoven fabric is stacked on the surface of the absorbent body is placed on a flat acrylic plate, an autoburette (injection speed: 7 ml / min) is used to center the central portion R1 and 5 mm above the nonwoven fabric. 7 ml (1 minute) of artificial menstrual blood was dropped onto the sample from the height position. And after leaving the artificial menstrual blood dripping for 3 minutes, see the diffusion area (length in the length direction × diffusion length in the width direction) of the absorber surface seen through the nonwoven fabric and the acrylic plate. The visible diffusion area of the back surface of the absorber was measured as the first absorber surface diffusion area and the absorber back surface diffusion area, respectively.

  Next, 7 ml (1 minute) of artificial menstrual blood was dropped onto the sample from the center of the central portion R1 and a height of 5 mm above the nonwoven using an autoburette (injection speed 7 ml / min) again. After completion of dropping of artificial menstrual blood, it was left for 3 minutes. And the diffusion area of the absorber surface seen through from a nonwoven fabric and the diffusion area of the absorber back surface seen through from an acrylic board were measured as the 2nd absorber surface diffusion area and absorber back surface diffusion area, respectively.

  Next, 7 ml (1 minute) of artificial menstrual blood was dropped onto the sample from the center of the central portion R1 and a height of 5 mm above the nonwoven using an autoburette (injection speed 7 ml / min) again. After completion of dropping of artificial menstrual blood, it was left for 3 minutes. And the diffusion area of the absorber surface seen through from a nonwoven fabric and the diffusion area of the absorber back surface seen through from an acrylic board were measured as a 3rd absorber surface diffusion area and absorber back surface diffusion area, respectively.

  Finally, after the third dripping of artificial menstrual blood is completed, the length of the absorbent back surface seen through the acrylic plate and the diffusion length in the length direction of the absorbent body surface seen through the nonwoven fabric are allowed to stand for 30 minutes. The longitudinal diffusion length was measured as the maximum absorber surface diffusion length and the maximum absorber back surface diffusion length, respectively. The measurement results of the first, second, and third absorber surface diffusion areas and the absorber back surface diffusion area are shown in FIGS. 10, 11, and 12, respectively. The maximum absorber surface diffusion length and the maximum The measurement result of the absorber back surface diffusion length is shown in FIG.

[Discussion]
When comparing the penetration time of artificial menstrual blood for the absorbents of Example 7, Comparative Example 1, and Comparative Example 3 having the same SAP density in the center, as shown in FIG. 8, Example 7, Comparative Example 3, and Comparative Example The penetration time of artificial menstrual blood became clear in the order of Example 1. In the absorbers of Example 7, Comparative Example 3, and Comparative Example 1, the SAP density in the central part is smaller than the SAP density in the peripheral part, the SAP density in the central part is equal to the SAP density in the peripheral part, and the central part, respectively. Therefore, it was found that artificial menstrual blood can be effectively absorbed by making the SAP density in the central part smaller than the SAP density in the peripheral part.

When the rewet was compared for the absorbers of Examples 1 to 7, as shown in FIG. 9, it was revealed that the rewet of the absorber other than the absorber of Example 2 was 40% or less. Since the SAP density (0.017 g / cm ₃ ) in the absorbent body of Example 2 is smaller than the SAP density in the absorbent bodies of the other examples, the SAP density in the central portion is therefore the SAP density in the absorbent body of Example 3. It is presumed that a density (0.033 g / cm ₃ ) or higher is desirable. Moreover, since the rewet of the peripheral part of the absorbers of Examples other than Example 2 is better than that of the absorber of a comparative example, according to the absorber of an Example, there is little feeling of the skin remaining of the diffuse menstrual blood. It became clear that we could do it.

When comparing the diffusion areas on the front and back sides of the absorbers of Examples 1 to 7, as shown in FIG. 11, the diffusion areas on the back side decreased in the order of the absorbers of Examples 1 to 7, and Example 6 7, the diffusion area on the back side of the absorber is almost the same. The SAP density at the center of the absorbent body of Example 7 is larger than the SAP density at the central part of the absorbent body of Example 6, and the diffusion area on the surface side of the absorbent body of Example 7 is the surface side of the absorbent body of Example 6. Since it is larger than the diffusion area, menstrual blood is not effectively absorbed from the front surface side to the back surface side of the absorber due to occurrence of blocking of menstrual blood by SAP in the absorber of Example 7, and absorption It is presumed that menstrual blood spread to the surface side of the body. From this, it was inferred that the SAP density in the central part of the absorber is preferably equal to or less than the SAP density (0.133 g / cm ₃ ) in the absorber of Example 6.

Further, when comparing the maximum diffusion lengths on the front and back sides of the absorbers of Examples 1 to 7, as shown in FIG. 13, the maximum diffusion lengths on the surface side of the absorbers of Examples 6 and 7 are different. It was found to be shorter than that of the example. From this, in order to realize a more preferable diffusion area, it was inferred that the SAP density in the central part is more preferably equal to or less than the SAP density (0.100 g / cm ₃ ) in the absorber of Example 5. In addition, according to the absorber of Examples 1-7, when the SAP density of the center part was in the said numerical range, the SAP density of the peripheral part was 0.133 g / cm < ₃ > or more.

  Moreover, when the absorber surface diffusion area and absorber back surface diffusion area of the 1st time, the 2nd time, and the 3rd time were compared about the absorber of Examples 1-7, as shown to FIGS. 10-12, as shown to FIGS. The same tendency was observed for each of the examples even after the second and third times and the SAP had expanded over time. From this, in the absorbers of Examples 1 to 7, it is difficult to cause menstrual blood blocking due to SAP expansion, and even when menstrual blood is repeatedly discharged, the occurrence of menstrual blood leakage can be effectively suppressed. Was inferred.

  As mentioned above, although the embodiment to which the invention made by the present inventors was applied has been described, the present invention is not limited by the description and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it should be added that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above embodiments are all included in the scope of the present invention.

It is a top view which shows the whole structure of the sanitary napkin used as embodiment of this invention. It is sectional drawing which shows the cross-section of the sanitary napkin in line segment AA shown in FIG. It is a top view which shows the whole structure of the absorber used as embodiment of this invention. It is a schematic diagram which shows the manufacturing system for manufacturing the sanitary napkin shown in FIG. It is a schematic diagram which shows the structure of the pattern plate drum shown in FIG. It is a schematic diagram which shows the structure of the upper stage roller of the absorber embossing apparatus shown in FIG. It is a schematic diagram which shows the structure of the lower stage roller of the absorber embossing apparatus shown in FIG. It is a graph which shows the result of having evaluated the penetration rate of artificial menstrual blood about the absorber of Examples 1-7 and Comparative Examples 1-3. It is a graph which shows the result of having evaluated rewet (returning performance) about the absorber of Examples 1-7 and Comparative Examples 1-3. It is a graph which shows the result of having evaluated the diffusion area of the 1st surface side and back surface side about the absorber of Examples 1-7 and Comparative Examples 1-3. It is a graph which shows the result of having evaluated the diffusion area of the 2nd surface side and back surface side about the absorber of Examples 1-7 and Comparative Examples 1-3. It is a graph which shows the result of having evaluated the diffusion area of the 3rd surface side and back surface side about the absorber of Examples 1-7 and Comparative Examples 1-3. It is a graph which shows the result of having evaluated the maximum spreading | diffusion length of the surface side and the back surface side about the absorber of Examples 1-7 and Comparative Examples 1-3.

Explanation of symbols

1: Sanitary napkin 11: Back sheet 12: Top sheet 13: Absorbent body R1: Center part R2: Peripheral part

Claims (4)

  A liquid permeable top sheet provided on the skin side surface, a liquid impermeable back sheet provided on the clothing side surface, and interposed between the top sheet and the back sheet, at least hydrophilic fibers and polymers. In the sanitary napkin, the absorbent body includes an absorbent body, the absorbent body has a central portion and a peripheral portion surrounding the central portion, and the thickness of the central portion of the absorbent body is larger than the thickness of the peripheral portion. The sanitary napkin is characterized in that the absorbent body is formed so that the density of the polymer absorbent body in the central part is smaller than the density of the polymer absorbent body in the peripheral part. The sanitary napkin according to claim 1, wherein the density of the polymer absorbent in the central portion is 0.033 g / cm ₃ or more. In the sanitary napkin according to claim 2, the sanitary napkin that lies in the range density of 0.033 g / cm ₃ or more 0.100 g / cm ₃ or less of the polymer absorber within the central portion. The sanitary napkin according to claim 2 or 3, wherein the density of the polymer absorbent in the peripheral portion is 0.133 g / cm ₃ or more.

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