JP2009254596A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article wherein a changed color of an indicator resulting from contact with fluid in urine or the like is visually recognizable and its moisture permeability can be maintained preferable. <P>SOLUTION: An absorbent article 10 has an absorber 3 and a back sheet 1 placed outside of the absorber, an indicator 13 the color of which changes resulting from contact with a fluid is placed between the absorber 3 and the back sheet 1, the back sheet 1 is equipped with a moisture-permeable sheet 11 on the side of the absorber and an exterior nonwoven fabric 12 outside of the absorber, a color difference between a color of the indicator 13 and a color of a part on which the indicator is placed as well as a color of the exterior nonwoven fabric 12 at least in its surrounding area w is less than 1.5 before the change of the color of the indicator and is 1.5 or more after the change of the color, and light transmission rates of the exterior nonwoven fabric 12 in the part on which the indicator is placed and at least its surrounding area w are 50% or higher. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an absorbent article for visually informing that urination has occurred.

  Various proposals have been made that have a function of visually informing the wearer and / or its guardian that the absorbent body absorbs and retains urine, menstrual blood, etc., when the absorbent article is worn. . For example, a disposable napkin having a black appearance and a white absorber or the like partially visible has been proposed (see Patent Document 1). Thereby, when it wears in combination with black underwear, the napkin is not conspicuous. On the other hand, if there is excretion of menstrual blood or the like, the absorber or the like is discolored, and the wearer can visually know that.

  Unlike the above, there are some that use a specific agent or a pH indicator that changes color when contacted with moisture by urination or the like as an indicator. Among them, a combination of a character design that does not change color and a design that changes color has been proposed as a method that focuses on visual effects, and is said to be effective for children's excretion training (see Patent Document 2). In addition, for the purpose of improving visibility, there is one in which the light transmittance of the back sheet disposed outside the indicator that makes it possible to visually recognize that the absorber is in a wet state is in a predetermined range (see Patent Document 3). . Further, there is proposed a printing method in which a colored layer that does not change color is formed on the front surface or the back surface of a back sheet (each sheet in the case of a plurality of sheets) arranged outside the color change indicator (Patent Document 4). ~ 8).

Japanese translation of PCT publication No. 2004-520856 Special table 2003-501209 gazette Special table 2007-117649 Japanese Utility Model Publication No.59-24704 JP 2004-337385 A Japanese Utility Model Publication No. 60-20509 JP 2004-057640 A JP 2004-089614 A

  In the absorbent article using the variable color indicator described above, the indicator is usually disposed at a position in contact with the absorber, and the back sheet is disposed on the outside thereof. Therefore, from the outside of the absorbent article, the color change of the indicator must be seen through the back sheet, and is difficult to visually recognize. Further, when the agent for changing color used for the indicator comes into contact with urine or the like, blurring may occur or the color or outline may be blurred. Further, if the visibility is emphasized and the indicator is made to have a conspicuous color, the cleanliness of the absorbent article that is usually used with the skin may be impaired. In this way, the wearer or guardian accurately confirms that there was urination visually even when the color is clean and visible through the back sheet, and in some cases bleeds. Notifying is not easy. On the other hand, if urination is left unattended for a long time, not only will it cause discomfort, but it may cause rough skin and rash in infants, for example, and parents will know that urination has occurred correctly as quickly as possible. There is a need.

  Also, if a pattern or design that does not change color in combination with an indicator is inadvertently printed and formed on the back sheet, the original function required for the back sheet may be affected. In particular, in the portion where the indicator is disposed, the absorber absorbs moisture and gets wet, so that it has high moisture permeability and is required to prevent the moisture inside the absorber as much as possible. For this reason, a back sheet having high moisture permeability has been developed and suitably used. However, when a coating film is formed on the surface of the back sheet, micropores in the sheet exhibiting moisture permeability are blocked. It also reduces the good moisture permeability.

  An object of the present invention is to provide an absorbent article that can easily visually recognize discoloration of an indicator due to contact with moisture contained in urine or the like and that can maintain good moisture permeability. Especially for the visibility of the indicator, it is intended to provide an absorbent article that makes the indicator noticeable and clean at the beginning of wearing, and makes it clearly visible after discoloration, and accurately informs that there was urination, etc. .

  An object of the present invention is to provide an absorptivity having an absorber and a back sheet disposed outside the absorber, and an indicator that changes color by contact with moisture between the absorber and the back sheet. The back sheet comprises the moisture-permeable sheet on the absorber side and an exterior nonwoven fabric on the outside thereof, and the color of the indicator, the portion where the indicator is disposed, and the color of the exterior nonwoven fabric in at least the peripheral region thereof The color difference is less than 1.5 before the indicator is discolored, is 1.5 or more after the indicator is discolored, and the light transmittance of the exterior nonwoven fabric is 50% or more in the portion where the indicator is disposed and at least the peripheral region thereof. Solved by an absorbent article.

  The absorbent article of the present invention easily recognizes the discoloration of the indicator due to contact with moisture contained in urine and the like, and in spite of having a colored region, impairs the good moisture permeability of the absorbent article. There is an excellent effect that it can be maintained without being damaged. In particular, regarding the visibility of the indicator of the absorbent article of the present invention, the appearance of the indicator is conspicuous and clean at the initial stage of wearing, and after this color changes, it is clearly recognized visually, for example, the clothing covering the absorbent article is slightly opened. It is possible to accurately notify that there was urination or the like even in the situation of looking through.

The present invention will be described in detail based on preferred embodiments with reference to the drawings.
FIG. 1 is a perspective view schematically showing a shape when a pants-type disposable diaper as a preferred embodiment of the absorbent article of the present invention is mounted. In the diaper 10 of the present embodiment, a waist opening t and a pair of left and right leg openings s are provided. The waist opening t is passed through the waist and waist of the wearer, and the leg opening s is passed through the thigh. Is done. A plurality of elastic members 6 forming waist gathers are disposed in the vicinity of the waist opening t, so that the waist circumference and waist circumference of the wearer are appropriately tightened to fit. Also, a plurality of elastic members 8 forming leg gathers are provided in the vicinity of the leg opening s, and a good fit is realized by appropriately tightening the thigh.

  In the diaper 10 of this embodiment, the side seal | sticker part 4 is provided and the front body side f and the back body side r of a diaper are joined here. However, in this invention, it is good also as a tape-type diaper which joins with a fastening tape at the time of wear, without providing the side seal part 4. FIG. Moreover, although the diaper 10 of this embodiment is illustrated as a diaper for infants, an diaper for adults may be used, and it can be set as the absorbent article made into a required form according to needs.

  What is necessary is just to use what is normally used for this kind of article | item as said each member which comprises the diaper 10 of this embodiment. For example, as the top sheet 2, a hydrophilic nonwoven fabric or an apertured film can be used. As the absorbent body 3, pulp, a highly water-absorbing polymer, or the like can be used. Various elastic materials can be used as the elastic members 6 and 8. The member which comprises the back seat | sheet 1, and its manufacturing method are demonstrated in detail later. Moreover, the method of assembling each of the above materials into a diaper is not particularly limited, and may be a normal manufacturing method applied to this type of disposable diaper.

2 is an enlarged cross-sectional view taken along the line II-II in FIG. As shown in FIG. 1 and FIG. 1, the disposable diaper 10 of this embodiment is provided with an indicator 13 that changes color when it comes into contact with moisture between the backsheet 1 and the absorber 3 (in the present invention). The discoloration is a concept in which the color changes before and after contact with moisture as described above, and includes the disappearance of the color upon contact with moisture and the appearance of the color upon contact with moisture. ). In the absorbent article of the present invention, the discoloration of the indicator may be changed to such an extent that a change in color (which may be any of hue, saturation, and brightness) can be recognized by visual observation, and the color difference is 1.5 or more. It is preferable that it is, and it is more preferable that it is 3.0 or more. In the present invention, “color difference” means a color difference in the L ^* a ^* b ^* color system (ΔE ^* ab = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ¹ unless otherwise specified. ^{/ 2} ).

  In the present embodiment, an indicator 13 is disposed on the inner side (skin contact surface side) of the moisture-permeable sheet 11 of the back sheet 1 (see FIG. 2). Here, the indicator applies, for example, a hot melt composition in which a pH indicator (for example, bromophenol blue) or the like is mixed with an adhesive component to the absorbent facing surface of the moisture permeable sheet 11, and the absorbent body 3 is placed on the absorbent facing surface. It can be arranged and formed. At this time, a mount or the like may be disposed between the absorber 3 and the indicator 13. Further, another functional sheet or the like may be provided between the moisture permeable sheet 11 and the indicator 13, between the moisture permeable sheet 11 and the exterior nonwoven fabric 12, or outside the exterior nonwoven fabric 12. These sheets or nonwoven fabric layers may have a structure composed of a plurality of layers.

  In the present embodiment, the indicator 13 is linearly provided from the diaper bottom c to the front body f at the central portion in the diaper width direction. And it is provided so that three elongate lines may be juxtaposed in the diaper width direction. Thus, the discoloration of the indicator 13 at the bottom of the diaper (the crotch part of the wearer) c or the front body side (the abdomen side of the wearer) f where urination is particularly concentrated can be recognized. Further, since a plurality of indicators 13 (three in this embodiment) are juxtaposed in the diaper width direction in the form of narrow strips, visual changes are more easily recognized.

  In the disposable diaper of the present invention, a colored region (hereinafter referred to as an invariant colored region) that does not substantially change color even when it comes into contact with moisture in the portion of the backsheet 1 on which the indicator is disposed and at least the region indicated by the peripheral region w. .) Is arranged. Here, the phrase “substantially no discoloration even when contacted with moisture in the back sheet” means a state where it is recognized that the color has not changed visually even if there is some color change. For example, a color change that occurs when moisture is absorbed by a sheet (typically a change that appears to be slightly darker when the sheet gets wet) is included in the meaning that the color does not change substantially.

  In the diaper 10 of the present embodiment, the color of the portion of the backsheet 1 on which the indicator is provided and the color of at least the peripheral region w is formed by coloring the exterior nonwoven fabric 12. That is, the moisture-permeable sheet 11 is not colored and is translucent milky white on the entire surface, and the region w of the exterior nonwoven fabric 12 (the invariant color region 12a of the exterior nonwoven fabric) is colored.

In the diaper 10 of the present embodiment, the color difference (ΔE ^* _i ) between the color before the discoloration of the indicator 13 and the exterior nonwoven fabric (that is, the invariant colored region 12a of the exterior nonwoven fabric) in the peripheral region w including the portion is present. It is less than 1.5, that is, a similar color. Therefore, before the water | moisture content by excretion reaches | attains the indicator 13, it is set as the appearance which the indicator 13 is not conspicuous and there is no sense of incongruity in appearance. Here, in the present invention, the color before the color change of the indicator 13 and the color of the invariant color region 12a of the exterior nonwoven fabric need not be the same color as long as they are similar colors, and the initial color difference (ΔE ^* _i ) is preferably 1.0 or less, particularly preferably 0.5 or less. There is no particular lower limit to the initial color difference (ΔE ^* _i ), but it is practical that the initial color difference (ΔE ^* _i ) is 0.1. More specifically, in this embodiment, the color of the indicator 13 is yellow before the color change, and contact with moisture. The color changes to blue-green. On the other hand, it is preferable that the invariant colored region 12a of the exterior nonwoven fabric is colored yellow and the non-colored region 12b in the peripheral region is white. The size of the peripheral area w of the indicator in the present embodiment is not particularly limited, but may be determined functionally in consideration of the influence on the viewer's visual recognition with respect to the change in the color of the indicator. It is good also as a range of 5-50 mm seeing from the distance. However, as will be described later, the color of the outer nonwoven fabric and the like may be constant beyond this region w in consideration of the production efficiency and the like.

When the indicator 13 comes into contact with moisture and turns blue-green, this blue-green line appears in the yellow area w, and the wearer or guardian (observer) clearly sees the color change. Can be recognized. In the absorbent article of the present invention, the color of the indicator after discoloration is not particularly limited, but from the viewpoint of visibility, the color of the indicator after discoloration and the color of the exterior nonwoven fabric (invariant color region 12a) in the peripheral region w thereof Terminal color difference (ΔE ^* _f ) is 1.5 or more, preferably 3.0 or more.

  Further, the visibility in the above color change will be described in detail. The change in which a figure (three lines in this embodiment) emerges from a region of the same color system as if there is nothing as described above is intriguing to the viewer. There is an effect that draws attention. That is, the color change can be strongly impressed by giving some surprise as if a foreign object appeared in a place where there is nothing at all or is not so conspicuous at all.

  By the way, as described above, in a normal absorbent article, the indicator is disposed at least on the inner side of the back sheet (the back side of the back sheet as viewed from the viewer), and the indicator sees the sheet through the sheet. . Therefore, the indicator inevitably has a blurred color. For example, even if the color changes from yellow to turquoise, if the backsheet is white, the indicator remains white and the impression given to the viewer is weakened. In some cases, it may not be remembered whether the initial color of the indicator was yellow or turquoise. After all, whether the color is the one before the color change (before urination, etc.), or after the color change (after urination, etc.) ).

  On the other hand, according to the diaper 10 of the present embodiment, the color of the indicator and the outline of the indicator as described above are visually recognized, and the viewer is strongly aware of the discoloration of the indicator 13 that cannot be achieved normally. Can be made. In addition, since the indicator 13 is raised only when there is a color change, even if a guardian or the like forgets the color before and after the color change, it can be determined that there was urination without misidentification. In this embodiment, the exterior nonwoven fabric is provided with the invariant color coloring region 12a so as to overlap the indicator 13. However, the coloring form in the present invention is not limited to this, and the exterior nonwoven fabric is not formed in the peripheral region w of the indicator 13. The discoloration coloring area | region 12a should just be provided. For example, an invariant colored region 12a of the exterior nonwoven fabric may be provided at a position slightly separated from the indicator 13 within a range where the above-described visual effect can be obtained.

  Moreover, you may make the invariant color coloring area | region 12a of an exterior nonwoven fabric into a gradation, a design pattern, etc., and the visual effect mentioned above further increases by these. Furthermore, in the aspect made into a pattern, either or both of the indicator 13 and the invariant color coloring region 12a of the exterior nonwoven fabric may be made into a graphic form, and these may be combined to form, for example, a human face or an animal. Thereby, the visual effect that the above-mentioned indicator appears can be further enhanced. Furthermore, if the above-mentioned pattern is made into a popular character, etc., when the wearer is an infant, a special impression is given to the wearer, and not only the skin feel but also the visual impression that there is urination Can be effective in diaper training.

  Next, the indicator will be described. As described above, the indicator is discolored by contact with moisture. Examples of the color changing substance contained therein include a pH indicator. When the absorbent article is a diaper as in this embodiment, it is preferable to use a pH indicator that changes color before and after contact with moisture such as urine. For example, bromophenol blue, methyl orange, arizan S, bromocresol green, methyl red, bromocresol purple, resazurin and the like that change color at pH 3-7 are preferred. In the present invention, the term “moisture” includes not only a liquid component composed solely of water but also an aqueous composition in which an acid, a base, a salt, an organic compound or the like is dissolved in water.

  As a method for immobilizing the indicator 13 on a predetermined sheet or the like, a method of applying to the surface as a hydrophilic composition in which a discoloring substance and an adhesive substance are mixed is simple and reliable. As the adhesive substance, a hydrophilic substance is preferable from the viewpoint of compatibility with the discoloring substance. Examples of such a substance include a hydrophilic polymer that functions as an adhesive. Examples of the hydrophilic polymer include polyethylene glycol (PEG), polypropylene glycol (PPG), polyvinyl alcohol (PVA), polyamide, vinyl pyrrolidone homopolymer, and the like. These hydrophilic polymers preferably have a number average molecular weight of 1,000 to 50,000, more preferably 2,000 to 20,000 from the viewpoint of providing reliable fixation. In addition, the material used for an indicator, the method of fixing to a sheet | seat, etc. can refer to Unexamined-Japanese-Patent No. 2004-337385, for example.

Next, the moisture permeable sheet will be described. Since the indicator 13 is recognized from the outside of the diaper through the moisture permeable sheet 11 as described above, it is preferable to use a moisture permeable sheet having high transparency so as to improve the visibility of the indicator. From such a viewpoint, the light transmittance of the moisture-permeable sheet 11 is preferably 20 to 100%, and more preferably 30 to 100%. The light transmittance is measured as follows.
[Light transmittance]
In the present invention, the light transmittance is a haze meter manufactured by Nippon Denshoku Industries Co., Ltd., trade name “NDH5000”, and the value of total light transmittance Tt is measured based on JISK7361-1. Arbitrary 10 points on the sheet to be measured are measured under these measurement conditions, and the average value is used as the light transmittance value in the present invention.

  Further, in the present embodiment, the color of the moisture permeable sheet 11 is not particularly limited, but for the purpose of making the indicator after discoloration easy to visually recognize, it is preferable that the color is white or the same color as the exterior nonwoven fabric 12. When a similar color is selected, the color difference between the exterior nonwoven fabric 12 and the moisture permeable sheet 11 is preferably less than 1.5, more preferably 1.0 or less, and particularly preferably 0.5 or less. preferable. If white is selected, use the moisture permeable sheet 11 with L * a * b * values of L * = 70 or more, a * = 0 ± 3, b * = 0 ± 3 In particular, it is more preferable to use L * = 85 or more, a * = 0 ± 2, and b * = 0 ± 2.

Moreover, it is preferable that the moisture permeable sheet 11 is liquid-impermeable and rich in moisture permeability. The moisture permeability of the moisture permeable sheet 11 is 0.5 to 4.0 g / (100 cm ² · hr) according to JIS Z0208, which is a value for a sample after storage for 1 hour at 30 ° C. and 90% humidity. It is preferably 1.0 to 4.0 g / (100 cm ² · hr).

  Examples of the material used for the moisture permeable sheet 11 include a porous film. For example, the porous film is formed by melt-kneading a resin composition comprising a hydrophobic thermoplastic resin and a fine inorganic filler made of calcium carbonate or the like, or an organic polymer incompatible with the resin, to form a film. The film is obtained by uniaxial or biaxial stretching. Examples of the thermoplastic resin include polyolefin. Examples of the polyolefin include high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, and polybutene, and these can be used alone or in combination. Although content of the thermoplastic resin in the said resin composition is not specifically limited, For example, it is preferable that it is 30-60 mass%.

  Although what is used as said filler is not specifically limited, For example, an inorganic filler is mentioned, It is preferable that a moisture-permeable sheet can be made porous and can fully provide moisture permeability. Examples of inorganic fillers include calcium carbonate, gypsum, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium phosphate, aluminum hydroxide, zinc oxide, titanium oxide, alumina, mica , Zeolite, carbon black, aluminum powder, iron powder and the like. These can be used alone or in combination of two or more. These inorganic fillers preferably have an average particle size of 0.3 to 8 μm and a maximum particle size of 20 μm or less from the viewpoint of ensuring the strength of the moisture-permeable sheet obtained and preventing sheet breakage during production. More preferably, the particle size is 0.5-5 μm and the maximum particle size is 15 μm or less.

Of the various inorganic fillers described above, calcium carbonate or barium sulfate is preferably used, and calcium carbonate is particularly preferably used. When using calcium carbonate, preferably it has a specific surface area of 16000~24000cm ² / g, more preferably 18000~22000cm ² / g. By using such a sheet, it is possible to obtain a sheet having high moisture permeability and high water resistance, that is, a sheet having a large number of dense holes and being hard to bleed and having sufficient strength. The inorganic filler in the resin composition is preferably 40 to 70 parts by mass with respect to 100 parts by mass of the thermoplastic resin. As a result, a moisture-permeable sheet having high moisture permeability can be obtained, the water resistance of the sheet can be maintained to make the liquid difficult to bleed, and sufficient strength and formability can be maintained.

  In the resin composition used as the moisture permeable sheet, in addition to the thermoplastic resin and the filler, a third component can be added in order to improve the supple texture and the handleability during production.

  In the diaper 10 of the present embodiment, the exterior nonwoven fabric 12 has a high light transmittance so that the indicator 13 can be sufficiently seen through, and the light transmittance of the invariant color region 12a of the exterior nonwoven fabric is 50% or more, preferably 70%. Above, especially preferably 80% or more. The upper limit is preferably 100%, but is practically 95% or less, and more practically about 90%.

Moreover, as the exterior nonwoven fabric 12, it is preferable to use a material with a soft touch that does not decrease the moisture permeability of the moisture permeable sheet and that can provide a good touch to the wearer and the guardian. Specifically, it is preferable to use a soft texture nonwoven fabric having the above properties. The basis weight of the nonwoven fabric is preferably 5 to 45 g / m ² and more preferably 10 to 40 g / m ² in consideration of the above properties.

  As a nonwoven fabric used for the exterior nonwoven fabric 12, for example, a single fiber of a thermoplastic resin made of a polyolefin such as polyethylene or polypropylene, or a polyester such as polyethylene terephthalate, or a core-sheath type or a side-by-side type using two or more of these resins. Nonwoven fabric composed of a composite fiber having the following structure.

  In the present embodiment, as described above, a part of the exterior nonwoven fabric 12 is colored with the same color as that of the indicator 13 before the color change. More specifically, it is preferable that the invariant colored region 12a of the exterior nonwoven fabric is colored yellow so that the yellow indicator 13 does not stand out before the discoloration. Coloring of the invariant colored region 12a of the exterior nonwoven fabric may be performed by a normal coloring method applied to the nonwoven fabric, and is not particularly limited. However, coloring by printing, coloring by fiber coloring (raw material coloring), or a combination of these two Examples include faded coloring. However, the coloration of the exterior nonwoven fabric in the present invention is preferably a coloration that “maintains the moisture permeability of the moisture permeable sheet” disposed on the inside thereof. It is preferable that the colored portion of the exterior has an area ratio that is twice or more the area of the indicator portion.

  Here, “the moisture permeability of the moisture permeable sheet can be maintained” means that the moisture permeability of the moisture permeable sheet is maintained without being reduced when used as a back sheet in combination with an exterior nonwoven fabric or the like. Even if it is destroyed, it means that the moisture permeability is maintained to the extent that it essentially does not affect the wearer's function to prevent stuffiness. Hot melt may be used when bonding the exterior nonwoven fabric and the moisture permeable sheet, but if the hot melt is applied too thickly on the entire surface of the moisture permeable sheet, the fine pores of the moisture permeable sheet are blocked and the moisture permeability is maintained. There is something difficult. Therefore, it is preferable to reduce the covering area by applying a hot melt in a pattern so as to maintain the moisture permeability of the moisture permeable sheet. Specifically, the moisture permeability ratio when the exterior nonwoven fabric or the like is disposed on the moisture permeability defined above of the moisture permeable sheet and used as a back sheet ({[moisture permeability of the back sheet] / [permeability] Moisture permeability of the wet sheet]} × 100) is preferably 30 to 100%, and more preferably 50 to 100%. However, considering that the moisture-permeable sheet and the exterior nonwoven fabric are well bonded so as not to peel off during wearing, it is practical that the upper limit of the ratio is 90%, preferably 85%.

Usually, when coloring a back sheet, a colored coating film is printed and formed on the surface of the moisture-permeable sheet. However, as described above, this will block fine holes formed in the moisture-permeable sheet. Even when a moisture permeable sheet having a high moisture permeability is produced, the good moisture permeability is greatly reduced or lost in the printed portion. In particular, the portion where the indicator is disposed is a region that mainly receives excretion of urine water, and it is desired to maintain high moisture permeability.
On the other hand, in the present invention, since the exterior nonwoven fabric is colored, moisture permeability can be maintained without inadvertently closing fine holes of the moisture permeable sheet. As a result, according to the present invention, it is difficult to achieve by simply forming a colored coating film on the surface of the moisture-permeable sheet and printing it, and it is possible to achieve both improved visibility of the indicator and maintenance of good moisture permeability. sell. However, the moisture-permeable sheet may be subjected to print printing or the like within a necessary range in the present invention.

  When the invariant color region 12a is colored by printing, coloring, a pattern, a pattern, or the like can be given even if the area is small or large. In particular, when the nonwoven fabric is a web-like structure formed by entanglement of thin fibers, the surface of the fibers can be colored by printing, and the amount of voids secured between the fibers can be substantially maintained, so that moisture permeability can be maintained. It is preferable in that it can be colored without substantially impairing the color.

  Here, printing on the non-woven fabric may be performed on the surface of the non-woven fabric (surface opposite to the wearer) or on the back surface (surface on the wearer side and on the moisture-permeable sheet side). By printing on the surface side of the exterior nonwoven fabric, the coloration is exposed to the outside of the exterior nonwoven fabric, and the printed color, pattern, pattern, etc. can be clearly seen by the wearer or guardian. For example, when it is desired to impress a baby or the like for diaper training or educational purposes, it is preferable to print on the surface side of the exterior nonwoven fabric in this way. On the other hand, by printing on the back side of the nonwoven fabric, it is difficult for the color to fade.For example, a stable coloring state is maintained even if the infant moves around and rubs or when the sheet including the outer nonwoven fabric is pulled up strongly when putting on a diaper. This is preferable.

Apart from the above, the invariant colored region 12a of the exterior nonwoven fabric can be colored by fiber coloring (raw material coloring). Specifically, the fiber coloring includes a method in which a fiber material in which a pigment is mixed and melted is spun and fiberized, a fiber is colored with a dye, and the color is left to change at high temperature. Thereby, a fiber colored in a desired color can be obtained, and the nonwoven fabric colored in that color can be obtained by processing the fiber by a predetermined method.
According to the coloring by fiber coloring, it is possible to suitably cope with the entire coloring of the diaper. In addition, an absorbent article colored in a desired color can be manufactured efficiently without requiring a separate printing process and the cost can be reduced. Maintaining productivity and keeping costs low in this way is extremely important when considering the use mode in which disposable articles are discarded once used. Furthermore, since the fibers themselves are colored, it is not necessary to form a coating film or the like with a colorant or the like on the surface after forming the nonwoven fabric. This is preferable in view of maintaining the soft texture of the nonwoven fabric itself, especially when considering that the outer nonwoven fabric is usually the outermost layer that directly touches the hand of the wearer or guardian.

As described above, the invariant color coloring region 12a of the exterior nonwoven fabric in the present embodiment has the same color as the color of the indicator 13 before the discoloration. Specifically, the b * value of the exterior nonwoven fabric and the indicator before discoloration is preferably 4 to 30, and the difference in b ^* between the exterior nonwoven fabric and the indicator before discoloration ([b ^* value of the indicator before discoloration] − [B ^* value of exterior nonwoven fabric] is preferably in the range of 0 to 0.5. In particular, the b ^* value of the L ^* a ^* b ^* color system is preferably 4 to 20 and more preferably 4 to 15 in the invariant color coloring region 12a of the exterior nonwoven fabric. By setting it as such a hue, it can respond | correspond to the color of what is practical as an indicator, and can maintain the clean external appearance of an absorbent article.

[L ^* a ^* b ^* L ^* value, a ^* value, b ^* value in the color system]
In the present ^{invention, L * a * b * L} * values in a color system, ^{a *} value, ^{b *} value, unless otherwise indicated, Nippon Denshoku Industries Co., Ltd. handy spectroscopic color difference meter NF777 (product Name), and the value obtained under the measurement conditions of illumination condition C, viewing angle condition 2 °, front light receiving condition = 0/45 °, and beam diameter φ10 mm. Specifically, when the measurement sample is a sheet-like material (exterior nonwoven fabric, moisture-permeable sheet, etc.), a plurality of sheets are mounted on the back side so that the thickness is 5 mm or more with 10 sheets of the sheet-like material stacked. Reflected light is measured in a stacked state, and in the case of an indicator, a value obtained by measuring in a state where a sufficient area of the indicator is provided on the mount and a plurality of white mounts are stacked on the back surface so as to have a thickness of 5 mm or more. Say. The mount used is L ^* = 95 or more, a ^* = 0 ± 2.0, and b ^* = 0 ± 4.0 with the number of sheets used for measurement being stacked. Specifically, examples of the white mount include L ^* = 96, a ^* = − 1.1, and b ^* = 3.7.

In addition, the moisture permeability of the exterior non-colored colored region 12a of the exterior nonwoven fabric is not particularly limited, but the moisture permeability is preferably higher than that of the moisture permeable sheet 11, and specifically 1.0 g / 100 cm ² · h or more. preferable. In order to obtain such a moisture-permeable exterior nonwoven fabric, there are a method of obtaining a nonwoven fabric using previously colored fibers, a method of aging under a certain environment, and the like. In the non-colored region 12b of the exterior nonwoven fabric, the light transmittance and moisture permeability are not particularly limited, but are preferably in the same range as the above-described invariant colored region 12a.

  The exterior nonwoven fabric 12 has a pattern or a pattern regardless of any of the invariant colored region 12a and the non-colored region 12b in order to enhance the visibility of the visual change of the indicator or improve the aesthetic appearance given by the appearance of the diaper. You may give it. The same applies to the moisture permeable sheet 11. For example, drawing a pattern such as an animal is preferable in terms of improving the appearance image of the entire article. However, it is preferable that the moisture permeable sheet 11 is not colored by printing or the like in the peripheral region w of the indicator 13. By doing in this way, as mentioned above, it is possible to more effectively realize both the provision of the colored region and the good moisture permeability in the backsheet 1 in which the moisture permeability is maintained by the interaction with the coloring of the exterior nonwoven fabric. .

  The exterior nonwoven fabric 12 and the moisture-permeable sheet 11 may be bonded in part or may be bonded over the entire surface. It is preferable to join the entire surface in consideration of the strength when the back sheet 1 is used. For example, as described above, the hot melt is partially applied to the nonwoven fabric in a specific pattern and then bonded to the moisture permeable sheet. Thus, the exterior nonwoven fabric 12 and the moisture permeable sheet 11 can be joined.

  The absorbent article of the present invention is not particularly limited as long as it absorbs and holds liquid excreted or leached from the wearer's body, and is preferably an article used in contact with or close to the wearer's skin. . Specifically, it is preferably a disposable absorbent article. For example, it is preferably used as a sanitary napkin, a panty liner or the like in addition to a disposable diaper.

FIG. 1 is a perspective view schematically showing a pants-type disposable diaper as a preferred embodiment of the absorbent article of the present invention. 2 is an enlarged cross-sectional view taken along the line II-II in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Back sheet 2 Top sheet 3 Absorbent body 4 Side seal part 6 Elastic member for waist gathers 8 Elastic member for leg gathers 10 Absorbent article (pants-type diaper)
DESCRIPTION OF SYMBOLS 11 Moisture permeable sheet 12 Exterior nonwoven fabric 12a Unchangeable color coloring area | region of exterior nonwoven fabric 12b Non-colored area | region 13 of exterior nonwoven fabric Indicator

Claims (3)

  An absorbent article having an absorbent body and a backsheet disposed outside the absorbent body, wherein an indicator that changes color by contact with moisture is disposed between the absorbent body and the backsheet, the backsheet Comprises a moisture permeable sheet on the absorber side and an exterior nonwoven fabric on the outside thereof, and the color difference between the color of the indicator and the color of the exterior nonwoven fabric in a portion where the indicator is disposed and at least the peripheral region thereof is before the indicator discoloration. The absorbent article which is less than 1.5, is 1.5 or more after indicator discoloration, and has a light transmittance of 50% or more in the portion where the indicator is disposed and at least the peripheral region thereof.   The exterior nonwoven fabric and the moisture permeable sheet are bonded together to form the back sheet, and the moisture permeability of the entire back sheet is the moisture permeability of the moisture permeable sheet in the portion where the indicator is disposed and at least the peripheral region thereof. The absorbent article according to claim 1, wherein the percentage of the divided value is 30 to 100%.   The b * value of the exterior nonwoven fabric and the b * value of the indicator before discoloration in the portion where the indicator is disposed and at least the peripheral region thereof are both 4 to 30, and the difference in b * obtained by subtracting the former from the latter is 0. The absorptive article according to claim 1 or 2 which is the range of -0.5.

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