JP2004337384A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article which facilitates the recognition of visual changes from outside including discoloring due to urination. <P>SOLUTION: The absorbent article 1 has an absorbing core 41 and paste boards 42a and 42b and a liquid-impermeable rear sheet 3 on the side opposite to the contact surface side with the user's skin of the absorbing core 41. The absorbing article 1 contains a hydrophilic composition 10 visually changeable when contacting the moisture at the specified part between the paste boards 42a and 42b and the rear sheet 3. The paste boards 42a and 42b are overlapped in several layers at the specified part across the thickness of the absorbent article 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to an absorbent article having a function of making a visual change before and after urination easy for an observer to understand, and for surely notifying a replacement time.
[0002]
Problems to be solved by the prior art and the invention
Until now, various types of disposable diapers having a function of notifying a replacement time when they become wet due to urination or the like have been proposed. For example, diapers containing a pH indicator that changes color when urine reaches the surface of the absorbent core opposite to the wearer contact surface are known (see Patent Documents 1 to 3). Also, a diaper containing an agent that changes color when wetted with water (Patent Document 4) is known.
[0003]
However, any of the techniques has a problem that the degree of discoloration is difficult to clearly recognize from outside. The reason for this is that since the agent that changes color is hydrophilic, when urine is sensed, the agent dissolves in the urine, causing bleeding and blurring of the color. Moreover, in order to sense urine, it is preferable to arrange a discoloring agent as close as possible to the absorbent core, so that when the agent is absorbed and diffused into the absorbent core, the color is more difficult to be recognized from the outside. . Also, since various patterns and the like are usually arranged on the diaper, the discolored portion is often arranged small so as not to impair the appearance of the entire diaper, and in such a case, the above phenomenon occurs. Then, the discoloration becomes more difficult to be recognized from the outside.
[0004]
[Patent Document 1]
JP-A-55-36326 [Patent Document 2]
JP-A-56-43402 [Patent Document 3]
JP-A-11-4852 [Patent Document 4]
JP-A-58-174601 [0005]
Therefore, an object of the present invention is to provide an absorbent article in which visual changes such as discoloration caused by urination are easily recognized from the outside.
[0006]
[Means for Solving the Problems]
The present invention is an absorbent article comprising an absorbent core and a backing sheet and a liquid-impermeable backing sheet on the side opposite to the wearer's skin contact side of the absorbent core, wherein the absorbent article is A predetermined portion between the backing sheet and the back sheet, contains a hydrophilic composition that changes visually when in contact with moisture, with respect to the thickness direction of the absorbent article, the mounting sheet in the predetermined portion is The object has been achieved by providing a plurality of overlapping absorbent articles.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. FIG. 1 shows a partially cutaway plan view of a disposable diaper as one embodiment of the present invention as viewed from a back sheet side. FIG. 2 is a sectional view taken along line II-II in FIG. In FIG. 2, the side of the back sheet 3 is drawn on the upper side. The diaper 1 has a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and an absorber 4 interposed between these two sheets 2, 3, and is formed substantially vertically. The absorber 4 is configured such that the periphery of the absorbent core 41 is covered with a mount 42 made of thin paper such as hydrophilic tissue paper. The mount 42 is used for the purpose of maintaining the shape retention of the absorbent core 41. An outer cover sheet 7 made of a nonwoven fabric is arranged on the outer surface (the side opposite to the absorber side) of the back sheet 3. The outer cover sheet 7 forms the outer edge of the diaper 1. The diaper 1 includes a crotch portion B, and a ventral portion C and a back portion A extending forward and backward from the crotch portion B. The back part A is a part located on the back side of the wearer when using the diaper. The abdominal part C is a part located on the abdomen of the wearer when using the diaper. Fastening tapes 8, 8 are provided on both left and right side edges of the back part A. The fastening tape 8 is fixed to a landing tape 9 provided on the exterior cover sheet 7 in the abdominal side C when the diaper is worn.
[0008]
The absorber 4 is sandwiched and fixed between the top sheet 2 and the back sheet 3. The waist portions 5 and 5 extending in the front-rear direction from the front and rear end edges of the absorber 4 and the leg portions 6 and 6 extending in the lateral direction from the left and right side edges are used to fit the diaper wearer to the wearer. The waist elastic member 51 and the leg elastic member 61 are provided. A three-dimensional guard is formed on each of the left and right sides in the longitudinal direction on the top sheet side of the diaper 1 (not shown). A solid guard elastic member is disposed at a free end of the solid guard to form a gather.
[0009]
As each of the members constituting the diaper 1 described above, those conventionally known in the art can be used without any particular limitation. For example, as the top sheet 2, a hydrophilic nonwoven fabric or an apertured film can be used. As the back sheet 3, a liquid impermeable film or the like can be used. As the absorbent core 41, a pile of fluff pulp and particles of a superabsorbent polymer can be used. Various elastomer materials can be used for the elastic members 61 and 71.
[0010]
As shown in FIGS. 1 and 2, the disposable diaper 1 of the present embodiment has a hydrophilic composition (hereinafter, referred to as a hydrophilic composition) between the back sheet 3 and the backing sheet 42, which visually changes when it comes into contact with moisture. 10). In the present embodiment, the changing agent 10 is provided on the surface of the backing sheet 42 provided on the back sheet 3 side, and the changing agent 10 faces the back sheet 3. More specifically, a modifier 10 composed of a hot melt composition in which a pH indicator (for example, bromophenol blue) or the like is mixed with an adhesive component is applied to the absorber-facing surface of the back sheet 3 by a method described later. On the opposing surface, the absorber 4 in which the absorbent core 41 is covered with the mount 42 is placed. In the present invention, "visually changing" is a concept including a case where a color changes before and after contact with moisture, a case where a color disappears upon contact with moisture, and a case where a color appears upon contact with moisture. It is. The changing agent 10 of the present embodiment corresponds to the case where the color changes before and after contact with moisture.
[0011]
In the present embodiment, the changing agent 10 is provided linearly across the back part A, the crotch part B, and the abdomen part C of the diaper at the center in the diaper width direction. More specifically, three elongated lines are provided in parallel in the diaper width direction. As in the disposable diaper 1 of the present embodiment, the presence of the changing agent 10 in the crotch portion B allows the changing agent 10 to visually change when urine is absorbed by the absorber 4 and reaches the back sheet 3. Then, it is possible to notify the time of replacement of the diaper 1.
[0012]
The greatest feature of the disposable diaper 1 of the present invention is that, in the thickness direction, a plurality of mounts 42 are overlapped at a portion where the changing agent 10 exists. More specifically, in the disposable diaper 1 of the present embodiment, as shown in FIG. 2, the absorbent core 41 is covered with a single mount 42, and the mount 42 has left and right side portions 42a and 42b, The absorbent core 41 overlaps with a predetermined width on the side facing the back sheet 3 to form a double. The changing agent 10 is provided so as to be in contact with the doubly-mounted mount 42. By adopting such a configuration, it is possible to enhance the recognizability of a visual change for notifying the time of replacing the diaper 1.
[0013]
In the disposable diaper of the present invention, the mechanism for enhancing the recognizability of a visual change is presumed as (1) to (3) below.
(1) The urine reaches the place where the changing agent 10 is present, and the changing agent 10 is discolored. At the same time, the changing agent 10 elutes or disperses in the urine and moves into the first-layer backing sheet 42a in contact with the back sheet 3. The amount of the change agent 10 tends to slightly shift to the second-layer backing sheet 42b, which is closer to the absorbent core 41 than the first-layer backing sheet 42a. Is fixed on the first-layer backing sheet 42a, and hardly transfers to the second-layer backing sheet 42b.
(2) The backing sheet 42b of the second layer is already wet when urine is transferred to the back sheet 3. Therefore, it is in a state where it is difficult to absorb the liquid more positively. This is also considered to be one reason that the change agent 10 hardly migrates to the second-layer backing sheet 42b.
(3) The presence of the second-layer backing sheet 42b prevents the first-layer backing sheet 42a in contact with the changing agent 10 from directly contacting the absorbent core 41. This prevents the change agent 10 from being diffused in the plane direction by the absorbent core 41 and lightening the color of the change agent 10.
[0014]
As described above, in the present invention, not only the bleeding of the changing agent 10 in the mount 42 but also (a) the fixing of the changing agent 10 to the first-layer mount 42a, and (b) the mount 42 and The second mount 42 b prevents the change agent 10 from being diffused and lightened by the absorbent core 41, thereby improving the visual recognition of the change by the change agent 10. Conceivable.
[0015]
In order to achieve the above-mentioned effects more reliably, it is preferable that the backing sheet 42 is hydrophilic. Further, it is preferable that the basis weight per mount sheet is 5 to 30 g / m ² . In particular, in consideration of ensuring that the changing agent 10 is fixed to the first layer of the backing sheet 42a and that the urine reaches the back sheet 3 at an appropriate speed, the basis weight per one backing sheet is considered. Is more preferably 10 to ²⁰ g / m ² . In the present embodiment, since the first-layer backing sheet 42a and the second-layer backing sheet 42b are made of one sheet 42, the first-layer backing sheet 42a and the second-layer backing sheet 42b have the same floor space. Volume and have the same thickness.
[0016]
The first-layer backing sheet 42a and the second-layer backing sheet 42b do not have to be formed of one sheet. In this case, the first-layer backing sheet 42a and the second-layer backing sheet 42b may be made of the same material or different materials. In the case of different kinds of materials, if a material having a density higher than that of the first-layer backing sheet 42a is used as the second-layer backing sheet 42b, the transfer of the changing agent 10 to the second-layer backing sheet 42b is further prevented. It is possible to further enhance the recognizability of the visual change. In this case, the basis weight per sheet of the backing sheet 42 is set in the above range, and the difference in density between the backing sheet 42a of the first layer and the backing sheet 42b of the second layer is 0.01 to 0.5 g / cm. ^{A value of 3} is preferable from the viewpoint that a decrease in the speed at which moisture such as urine reaches the change agent 10 can be prevented. Regarding the thickness of the backing sheet 42, both the backing sheets 42a and 42b have a thickness of about 0.02 to 1 mm, so that the amount of the changing agent 10 can be held in such an amount that a visual change can be easily recognized, and the transfer is carried out by moisture. It is preferable because the changing agent 10 can be sufficiently fixed.
[0017]
In order that the visual change of the change agent 10 can be clearly recognized from the outside of the diaper, it is preferable that the mount 42 has low transparency and high whiteness. The transparency is preferably 20% or less. The whiteness is preferably such that the b * value of the color coordinate index of the L * a * b * color system (CIE1976) is 3 to a minus value, particularly 1 to -5, particularly 0 to -5. The mount 42 having such transparency and whiteness can be obtained, for example, by using bleached pulp or by adding a filler to the mount. The absorbent core 41 preferably has a high degree of whiteness, but in the present invention, since the mounts 42a and 42b are overlapped, the color of the absorbent core 41 (particularly, yellowish color) is less likely to appear. There is an advantage that the visual change of the changing agent 10 is easily recognized from the outside of the diaper even if it has a tint.
[0018]
The b * value is measured by a color difference meter. In the present invention, using a handheld spectral color difference meter NF777 (trade name) manufactured by Nippon Denshoku Industries Co., Ltd., measurement of illumination condition C, viewing angle condition 2 °, front light receiving condition = 0/45 °, and light beam diameter φ10 mm was performed. Under the conditions, the measurement is performed by measuring the reflected light in a state where a plurality of mounts are stacked on the back side of the measurement sample so as to have a thickness of 5 mm or more.
[0019]
The first-layer backing sheet 42a and the second-layer backing sheet 42b, which overlap each other, have a hydrophobic adhesive property in at least a part of an overlapping portion of the diaper 1 with a region where the changing agent 10 is present. It is preferable that they are adhered to each other with an agent (for example, a hot melt adhesive). This prevents urine from being diffused in the diaper width direction on the first-layer backing sheet 42a, thereby further suppressing color bleeding due to the diffusion of the changing agent 10. The position where the hydrophobic pressure-sensitive adhesive is provided is preferably located outside the center in the diaper width direction in the region where the changing agent 10 is present.
[0020]
In the present embodiment, by providing the changing agent 10 from the abdominal part C to the dorsal part A along the diaper longitudinal direction, the visual change of the changing agent 10 in the crotch part B can be changed. It is possible to clearly recognize by comparing with the back part A and the abdominal part C, which are relatively difficult to occur. Moreover, since a plurality of the changing agents 10 are arranged in a narrow band shape in the width direction of the diaper (three in the present embodiment), the visual change is more easily recognized.
[0021]
Next, the changing agent 10 used in the present invention will be described. The change agent is a hydrophilic composition containing a substance that changes visually upon contact with moisture (hereinafter, referred to as a discoloration substance). Examples of the color changing substance include a pH indicator and the like. For example, known inks or indicators can be used. When the absorbent article is a disposable diaper as in the present embodiment, it is preferable to use a pH indicator whose color changes before and after contact with urine. For example, bromophenol blue, methyl orange, Alizan S, bromocresol green, methyl red, bromocresol purple, resazurin, and the like that changes color at a pH of 3 to 7 are preferable.
[0022]
The change agent 10 needs to be stably immobilized on the surface of the back sheet 3 and / or the backing sheet 42 until it comes into contact with moisture. As a method of realizing such fixation, a method of applying the changing agent 10 as a hydrophilic composition obtained by mixing a color changing substance and an adhesive substance on the surface of the back sheet 3 or the backing sheet 42 is simple and reliable. is there. As the tacky substance, a substance having hydrophilicity is preferable from the viewpoint of compatibility with the discoloration substance. Such a substance includes, for example, a hydrophilic polymer that functions as an adhesive between the backing sheet 42 and the back sheet 3 before coming into contact with moisture. Examples of the hydrophilic polymer include polyethylene glycol (PEG), polypropylene glycol (PPG), polyvinyl alcohol (PVA), polyamide, and vinylpyrrolidone homopolymer. The number average molecular weight of these hydrophilic polymers is preferably from 1,000 to 50,000, particularly preferably from 2,000 to 20,000, from the viewpoint of providing reliable immobilization.
[0023]
The changing agent 10 is recognized from the outside of the diaper through the back sheet 3. Therefore, it is preferable to use a material having high transparency as the back sheet 3 in order to improve visibility. However, if the transparency is too high, excrement may be seen through from the outside of the diaper. From such a viewpoint, the light transmittance of the back sheet 3 is preferably 30 to 80%, particularly preferably 35 to 80%.
[0024]
The light transmittance of the back sheet 3 is measured as follows.
<Measurement method of light transmittance>
The value of the total light transmittance Tt is measured using a measurement light source A light source under the trade name “HR-100” manufactured by Murakami Color Research Laboratory. Any 10 points on the back sheet are measured, and the average value is used as the light transmittance value.
[0025]
In addition to having the above light transmittance, the back sheet 3 is preferably liquid-impermeable and moisture-permeable. According to JIS Z0208, the moisture permeability of the back sheet 3 is 0.5 to 4.0 g / (100 cm ² · hr), which is a value of the sample after storage at 32 ° C. for 1 hour, and is suitable for the inside of the diaper. It is preferable from the point that comfortable wear can be obtained by proper humidity adjustment, and that leakage of body fluid is prevented.
[0026]
As a material used for the back sheet 3 having such liquid impermeability and moisture permeability, for example, a porous film may be mentioned. For example, a porous film is formed by melting and kneading a hydrophobic thermoplastic resin and a fine inorganic filler such as calcium carbonate or an organic polymer incompatible with the resin to form a film. Or it is obtained by biaxial stretching. Examples of the thermoplastic resin include polyolefin. Examples of the polyolefin include high- to low-density polyethylene, linear low-density polyethylene, polypropylene, polybutene, and the like, and these can be used alone or as a mixture.
[0027]
It is preferable to use a porous film having a basis weight of 10 to 40 g / m ² as a material of the back sheet 3 because the visual change of the changing agent 10 can be easily recognized from the outside of the diaper and a soft touch can be obtained.
[0028]
The exterior cover sheet 7 preferably has a predetermined light transmittance so that a visual change of the change agent 10 can be easily recognized. The light transmittance of the exterior cover sheet 7 is preferably 50% or more, more preferably 55% or more, and particularly preferably 60% or more. The method for measuring the light transmittance is as described above.
[0029]
It is preferable to use a nonwoven fabric having a basis weight and / or a thickness that allows the light transmittance to be obtained, so that the changing agent 10 can be seen through the outside of the diaper. When the nonwoven fabric has a basis weight of 5 to 45 g / m ² , particularly 10 to 40 g / m ² , both the recognizability of the visual change of the changing agent 10 and the sensual performance such as texture and feel are compatible. Preferred from the point.
[0030]
As the nonwoven fabric used for the exterior cover sheet 7, for example, fibers of a thermoplastic resin alone made of a polyolefin such as polyethylene or polypropylene, or polyester such as polyethylene terephthalate, or a core-sheath type or side-by-side made of two or more of these resins Non-woven fabrics composed of conjugate fibers having a mold structure are exemplified.
[0031]
As the nonwoven fabric used for the exterior cover sheet 7, it is preferable to use a nonwoven fabric having a high ground color transparency and a high whiteness because the visual change of the change agent 10 is enhanced. However, the exterior cover sheet 7 may be configured such that, in the diaper thickness direction, in the overlapping portion with the region where the changing agent 10 is arranged, most of the overlapping portion is white, and in the region other than the overlapping portion, the changing agent 10 Printing may be performed within a range that does not hinder the recognizability of the visual change.
[0032]
In the present embodiment, three changing agents 10 are arranged side by side in the diaper width direction in a narrow band shape, but the present invention is not limited to this, and the number of changing agents may be one or four or more. . In addition, it is also possible to provide a pattern that does not visually change even when it comes into contact with moisture on the back sheet 3 or the outer cover sheet 7 so as not to overlap the changing agent 10. In the case where such a pattern is provided, for example, when the changing agent 10 changes color before and after contact with moisture, a pattern having substantially the same color as the color of the changing agent 10 before or after the change. Is preferable because it is easier to recognize a change in color.
[0033]
The absorbent article of the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the fastening tapes 8 and 8 are provided on the left and right side edges of the back side portion A. Instead, a pair of waist bands extending laterally are provided on the left and right side edges of the back side portion A. May be provided. Then, a band fastening portion may be provided at the tip of one of the waistbands, and the left and right waistbands may be fastened to the abdomen or the back of the wearer by the fastening portion.
[0034]
Although the above embodiment relates to the unfoldable disposable diaper, the present invention is similarly applicable to other absorbent articles, for example, pants-type disposable diapers, sanitary napkins, sanitary shorts, and the like. .
[0035]
【The invention's effect】
In the absorbent article of the present invention, a visual change indicating the replacement time due to urination is very easy to recognize from the outside of the diaper.
[Brief description of the drawings]
FIG. 1 is a partially broken plan view of a disposable diaper as one embodiment of the present invention as viewed from a back sheet side.
FIG. 2 is a sectional view taken along line II-II in FIG.
[Explanation of symbols]
1 disposable diapers (absorbent articles)
2 Top sheet 3 Back sheet 4 Absorber 41 Absorbent core 42 Mount 42a First layer mount 42b Second layer mount 5 Waist section 6 Leg section 7 Exterior cover sheet 8 Fastening tape 9 Landing tape 10 Hydrophilic composition Object (change agent)

Claims (5)

An absorbent article comprising an absorbent core and a backing sheet and a liquid-impermeable backing sheet on the side opposite to the wearer's skin contact surface side of the absorbent core,
The absorbent article includes a hydrophilic composition that visually changes when contacted with moisture at a predetermined portion between the mount and the back sheet.
An absorbent article in which a plurality of the mounts are overlapped at the predetermined portion in the thickness direction of the absorbent article. The absorbent article of claim 1 wherein the basis weight per sheet of the mount is a 5 to 30 g / ^{m 2.} The absorbent article according to claim 1, wherein the hydrophilic composition contains a component that functions as an adhesive between the backing sheet and the back sheet before coming into contact with moisture. Each of the overlapping mounts is adhered to each other with a hydrophobic adhesive in a part of an overlapping portion with a region where the hydrophilic composition exists in a thickness direction of the absorbent article. The absorbent article according to any one of claims 1 to 3. The absorbent article is substantially vertically elongated and includes a crotch portion and a ventral portion and a dorsal portion extending back and forth from the crotch portion, wherein the hydrophilic composition extends from the abdominal portion to the dorsal portion. The absorbent article according to any one of claims 1 to 4, wherein the absorbent article is present along a longitudinal direction.

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