JP2023085129A - Absorbent article and indicator composition - Google Patents

Abstract

To provide an absorbent article equipped with an indicator which has increased visibility and responsiveness and can detect a change in urine specific gravity.SOLUTION: An absorbent article includes a top sheet layer, an absorber layer, an indicator layer, and a leak prevention layer in this order. The absorber layer includes a core wrap layer for covering the absorbent core layer and at least a side of the leak prevention layer of the absorbent core layer. The indicator layer is adjusted to an appearance color of an alkali side in an initial state before making contact with urine, changes into a color corresponding to urine specific gravity in making contact with the urine, and is arranged between the core wrap layer and the leak prevention layer by directly bonding to the core wrap layer and the leak prevention layer at least partially.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to absorbent articles and indicator compositions.

Among absorbent articles such as disposable diapers, there is known an absorbent article having an indicator capable of detecting the presence or absence of urination and changes in the health condition of the wearer by means of a change in color.

Indicators applied to absorbent articles can qualitatively indicate the specific gravity of the wearer's urine, as disclosed, for example, in US Pat.

In recent years, a urine detection indicator made of a thermoplastic solid material has also been put to practical use. For example, Patent Document 2 discloses a thermoplastic indicator composition. According to the same document, such an indicator composition can hold the wetness indicator in a desired position within the product, and the formation of intermolecular bonding forces may also contribute to the reduction of colorant leaching. can.

JP 2009-18183 A Japanese translation of PCT publication No. 2015-529151

In an absorbent article equipped with an indicator that can detect changes in urine specific gravity, it is easy to identify the difference in color according to the urine specific gravity, that is, high visibility, and it takes from the wearer's urination to the change in color of the indicator. Speed of time, that is, high responsiveness is required.

SUMMARY OF THE INVENTION An object of the present invention is to provide an absorbent article having an indicator capable of detecting changes in urine specific gravity with improved visibility and responsiveness.

One aspect (aspect 1) of the present invention is
It has a top sheet layer, an absorbent layer, an indicator layer, and a leak-proof layer in this order,
The absorbent layer has an absorbent core layer and a core wrap layer covering at least the leakproof layer side of the absorbent core layer,
The indicator layer is
In the initial state before contact with urine, the appearance color is adjusted to the alkaline side, and when it comes into contact with urine, the color can be changed according to the specific gravity of urine, and at least partially, the core wrap layer and the leak-proof layer are formed. directly joined and positioned between them,
It is an absorbent article.

In the absorbent article according to aspect 1, the indicator layer can change color depending on the urine specific gravity. More specifically, unlike the color change for detecting the presence or absence of urination (i.e., the color change from acidic color to alkaline color), it depends on urine specific gravity (i.e., urine sodium ion (Na ⁺ ), potassium ions (K ⁺ ), calcium ions (Ca ²⁺ ), magnesium ions (Mg ²⁺ ), etc.). When this happens, the wearer of the absorbent article or its assistant can easily recognize the change in the urine specific gravity.

An absorbent article using such an indicator layer is required to have high visibility from the viewpoint of more accurately confirming discoloration. In addition, the color change according to the urine specific gravity is useful for grasping the state of the wearer's body, such as the degree of growth and the presence or absence of dehydration. , should be done more quickly.

In the absorbent article according to aspect 1, the indicator layer is directly bonded to the core wrap layer and the leak-proof layer and arranged therebetween.

If the indicator layer is directly joined to the core wrap layer, the urine retained by the core wrap layer easily flows into the indicator layer through the joint. Therefore, the indicator layer discolors more quickly than when the indicator layer is not directly bonded to the core wrap layer. Therefore, responsiveness can be improved.

Also, when the indicator layer is directly bonded to the leak-proof layer, the indicator layer is easier to visually recognize from the leak-proof layer side than when the indicator layer is not directly bonded to the leak-proof layer.

That is, the absorbent article according to aspect 1 has high visibility and responsiveness.

Another aspect (aspect 2) of the present invention is the absorbent article according to aspect 1, wherein the indicator layer contains a thermoplastic component having a melting point or softening point within the range of 40°C to 120°C. .

In the absorbent article according to aspect 2, the indicator layer contains a thermoplastic component having a melting point or softening point within the range of 40°C to 120°C. When the indicator layer contains a thermoplastic component having a melting point or softening point within such a range, for example, when the absorbent article is manufactured, the indicator layer is applied to the leak-proof layer at the melting point or softening point. The absorbent article of aspect 1 can be readily formed by placing and optionally pressing a core wrap layer over the indicator layer before the indicator layer solidifies.

Furthermore, absorbent articles are typically used at temperatures below 40°C, for example around 36°C, which is the typical body temperature of the wearer. Therefore, the indicator layer is less likely to be deformed by temperature during use, and, for example, the bonding between the indicator layer and the core wrap layer and the leak-proof layer is less likely to be destroyed by the action of the wearer.

That is, the absorbent article according to aspect 2 has high productivity and durability while achieving high visibility and responsiveness.

Still another aspect (aspect 3) of the present invention is the absorbent article according to aspect 1 or 2, wherein the indicator layer further contains at least one of a hydrophilic polymer and an amine cationic surfactant. contains.

In the absorbent article according to aspect 3, the indicator layer further contains at least one of a hydrophilic polymer and an amine cationic surfactant. Therefore, the color change is highly responsive to changes in the urine specific gravity when the indicator layer comes into contact with urine, and the color can be clearly changed even when the amount of change in the urine specific gravity is small.

That is, the absorbent article according to aspect 3 has high responsiveness.

Still another aspect (aspect 4) of the present invention is the absorbent article according to any one of aspects 1 to 3, wherein the indicator layer changes color to blue or green when coming into contact with low specific gravity urine, It turns yellow or orange on contact with specific gravity urine.

In the absorbent article according to aspect 4, the indicator layer has a low specific gravity, unlike the color change for detecting the presence or absence of urination (that is, the color change of the pH indicator in the indicator from the acidic color to the alkaline color). It turns blue or green when it comes into contact with urine of high specific gravity, and turns yellow or orange when it comes into contact with urine of high specific gravity. The assistant can easily recognize the change in urine specific gravity, and in particular, the color change from the initial color before contact with urine to yellow or orange when contact with high specific gravity urine is easier to visually recognize.

That is, the absorbent article according to aspect 4 can more accurately and easily detect changes in urine specific gravity.

Still another aspect (aspect 5) of the present invention is the absorbent article according to any one of aspects 1 to 4, wherein the indicator layer contains a liquid component that is liquid at 36° C., and When the absorbent article is viewed from the stacking direction, the liquid component impregnates the leak-preventing layer in at least a portion of the portion of the leak-preventing layer that overlaps with the indicator layer.

When the leak-proof layer is impregnated with the liquid component, the gap between the indicator layer and the leak-proof layer and the fine space inside the leak-proof layer are filled with the liquid component. Therefore, irregular reflection of the part concerned is suppressed, and the visible light transmittance becomes higher than that of other parts of the anti-leakage layer.

As a result, in the absorbent article according to aspect 5, when the absorbent article is viewed from the stacking direction, the visible light transmittance of at least a portion of the portion overlapping the indicator layer in the leak-proof layer is high, and the leak-proof layer side has a high visible light transmittance. It is easier to visually recognize the discoloration of the indicator layer.

Still another aspect (aspect 6) of the present invention is the absorbent article according to any one of aspects 1 to 5, wherein the leak-proof layer is a hydrophobic nonwoven fabric layer, and the indicator layer is It has a leak-proof layer-impregnated portion that is embedded in the leak-proof layer.

When the leak-proof layer is a hydrophobic non-woven fabric layer, it is possible to release volatile components in urine, such as water vapor, while suppressing leakage of liquid in urine to the opposite side of the leak-proof layer. However, such layers typically tend to have lower visible light transmission than non-porous layers due to the difference in refractive index between the air in the voids of the nonwoven and the material forming the leakproof layer. .

The absorbent article according to aspect 6 has a leak-proof layer-impregnated portion in which the indicator layer is embedded in the leak-proof layer.

If the indicator layer enters the leak-proof layer, the thickness of only the leak-proof layer where the indicator layer does not enter in the portion overlapping the leak-proof layer-impregnated portion when viewed from the lamination direction of the absorbent article is thinner than the thickness of only the leak-proof layer in which the indicator layer does not enter. Therefore, when viewed from the lamination direction of the absorbent article, the portion overlapping the leak-proof layer-impregnated portion has higher visibility of the indicator layer when viewed from the leak-proof layer side.

That is, in the absorbent article according to aspect 6, when the absorbent article is viewed from the stacking direction, the visible light transmittance of at least a portion of the portion of the leak-proof layer that overlaps with the indicator layer is high, and the visible light transmittance is high from the leak-proof layer side. It is easier to visually recognize the discoloration of the indicator layer.

Still another aspect (aspect 7) of the present invention is the absorbent article according to any one of aspects 1 to 6, wherein a back It further has a sheet layer, and when the absorbent article is viewed from the stacking direction, the basis weight of at least a portion of a region of the backsheet layer that overlaps with the indicator layer is the same as that of the other part of the backsheet layer. smaller than the portion.

In the absorbent article according to Aspect 7, the basis weight of at least a portion of the region of the backsheet layer that overlaps with the indicator layer is smaller than that of the other portion of the backsheet layer when viewed from the stacking direction.

As a result, in the absorbent article according to aspect 7, discoloration of the indicator layer is more easily visible from the back sheet layer side.

Still another aspect (aspect 8) of the present invention is the absorbent article according to any one of aspects 1 to 7, wherein when the absorbent article is viewed from the lamination direction, the indicator layer is closer to the protective layer than the indicator layer. The layer on the leakage layer side has a visible light transmittance of 30.0% or more and 90.0% or less in the visible spectral range at least in a region overlapping with the indicator layer.

In the absorbent article according to aspect 8, in the region where the layer closer to the leak-preventing layer than the indicator layer overlaps at least the indicator layer, the total of all the layers is 30.0% or more and 90.0% in the visible spectrum region. It has the following visible light transmittance.

In the absorbent article according to aspect 8, the layer on the anti-leakage layer side has a predetermined visible light transmittance. Therefore, the change in color of the indicator layer can be detected through the layer closer to the leak-proof layer than the indicator layer, while feces and urine cannot be visually recognized through those layers.

In addition, "the layer closer to the anti-leakage layer than the indicator layer" means all the layers disposed on the opposite side of the indicator layer to the side on which the absorber layer is disposed when viewed from the stacking direction. be. Therefore, for example, when the absorbent article is arranged in the order of top sheet layer/absorbent layer/indicator layer/leak-proof layer/... other layers... "Layer" means the leakproof layer and the above "other layers".

Still another aspect (aspect 9) of the present invention is the absorbent article according to any one of aspects 1 to 8, wherein the indicator layer has a core wrap layer impregnated portion that is embedded in the core wrap layer. ing.

In the absorbent article according to Aspect 9, the indicator layer has a core wrap layer impregnated portion that is embedded in the core wrap layer. In the core wrap layer, urine tends to move through the core wrap layer-impregnated portion to the entire indicator layer. That is, the core wrap layer-impregnated portion functions as a path for urine flowing from the absorbent core layer to the core wrap layer to reach the entire indicator layer through the core wrap layer when the wearer urinates.

As a result, the absorbent article according to aspect 9 can achieve even higher responsiveness.

Still another aspect (aspect 10) of the present invention is the absorbent article according to aspect 9, wherein the area of the core wrap layer-impregnated portion is equal to the area of the indicator layer when the absorbent article is viewed from the stacking direction. of 20.0% or more.

In the absorbent article according to Aspect 10, on the premise of the structure of the absorbent article according to Aspect 9, when the absorbent article is viewed from the stacking direction, the area of the core wrap layer impregnated portion is larger than a predetermined ratio of the area of the indicator layer. is large, urine is particularly likely to move throughout the indicator layer along the core wrap layer-impregnated portion within the core wrap layer.

This makes it possible to achieve even higher responsiveness.

Still another aspect (Aspect 11) of the present invention is the absorbent article according to Aspect 9 or 10, wherein the core wrap layer-impregnated portion partially reaches the surface of the core wrap layer on the absorbent core layer side. , and is in contact with the absorbent core layer.

In the absorbent article according to aspect 11, such a configuration allows urine absorbed by the absorbent core layer to come into direct contact with the indicator layer.

As a result, the absorbent article according to aspect 11 can achieve even higher responsiveness.

In still another aspect (aspect 12) of the present invention, in the absorbent article according to aspect 11, when the absorbent article is viewed from the stacking direction, the surface of the core wrap layer-impregnated portion on the absorbent core layer side is The area of the portion reaching up to is 50.0% or less of the area of the indicator layer.

In the absorbent article according to aspect 12, with the above configuration, urine that reaches the indicator layer from the absorbent core layer side of the core wrap layer through the core wrap layer impregnated portion passes through the core wrap near the portion of the indicator layer on the core wrap layer side. It is easy to diffuse in the surface direction by the layer, and it is particularly easy to move the urine to the entire indicator layer. This makes it possible to achieve even higher responsiveness.

Still another aspect (Aspect 13) of the present invention is the absorbent article according to any one of Aspects 1 to 12, wherein when the absorbent article is viewed from the stacking direction, the absorbent core layer has the At least a portion of the area overlapping the indicator layer has a greater density than other areas of the absorbent core layer.

In a portion of the absorbent core layer having a higher density than other regions, such as around an embossed portion, urine moves faster in the thickness direction than in other portions. This is because urine tends to move along the high-density portion.

In the absorbent article according to aspect 13, when the absorbent article is viewed from the stacking direction, the portion of the absorbent core layer having a higher density than other regions overlaps at least a portion of the region overlapping the indicator layer. there is Therefore, when the wearer urinates, it is easier for the urine to move to the indicator layer more quickly.

As a result, the absorbent article according to aspect 13 can achieve even higher responsiveness.

Still another aspect (aspect 14) of the present invention is the absorbent article according to any one of aspects 1 to 13, wherein the indicator layer impregnates both the core wrap layer and the leak-proof layer. It has no non-impregnated parts.

The non-impregnated portion of the indicator layer has a higher density of components constituting the indicator layer than the portion impregnated with the core wrap layer and the leak-proof layer. Therefore, the non-impregnated portion is more discolored by urine than the portion impregnated with the core wrap layer and the leak-proof layer.

As a result, the absorbent article according to aspect 14 can achieve higher visibility.

In still another aspect (aspect 15) of the present invention, the absorbent article according to any one of aspects 1-14 is for toilet training.

In order to start potty training, it is necessary to reach a certain level of mental and physical development in infants, such as brain function and urinary function. .

In the absorbent article according to aspect 15, the indicator layer responds to urine, and the response of the toilet training indicator to urine differs depending on the growth state of the infant. can grasp.

Still another aspect (aspect 16) of the present invention is that the appearance color is adjusted to an alkaline side in the initial state before contact with urine, the color can be changed to a color according to the urine specific gravity when in contact with urine, and the temperature is 40 ° C. An indicator composition containing a thermoplastic component having a melting or softening point within the range of -120°C.

The indicator composition according to aspect 16 is adjusted to have an alkaline appearance color in the initial state before contact with urine, and can change color depending on urine specific gravity upon contact with urine. More specifically, unlike the color change for detecting the presence or absence of urination (i.e., the color change of the pH indicator in the indicator from the acidic color to the alkaline color), depending on the urine specific gravity (i.e., urine Depending on the concentration of ions such as sodium ions (Na ⁺ ), potassium ions (K ⁺ ), calcium ions (Ca ²⁺ ), magnesium ions (Mg ²⁺ ), etc.), the appearance color changes from the alkaline side, so disposable diapers, etc. When applied to the absorbent article, the wearer of the absorbent article or its assistant can easily recognize the change in the urine specific gravity.

And the indicator composition according to aspect 16 contains a thermoplastic component having a melting point or softening point within the range of 40°C to 120°C. Therefore, for example, when the absorbent article is manufactured, the indicator composition is applied to the leak-proof layer at the melting point or softening point, and the core wrap layer is placed on the indicator composition before the indicator composition solidifies. Thus, for example, absorbent articles according to aspects 1 to 15 can be easily formed.

According to the present disclosure, it is possible to provide an absorbent article having an indicator capable of detecting changes in urine specific gravity with improved visibility and responsiveness.

FIG. 1 is a schematic diagram of a disposable diaper 1 according to a first embodiment of the invention. FIG. 2 is an enlarged end view of a section of the disposable diaper 1 in FIG. 1 taken along line II-II. FIG. 3 is an enlarged view of region X in FIG. FIG. 4 is an enlarged view of a region similar to region X in FIG. 2 of the disposable diaper 1 according to the second embodiment of the invention. FIG. 5 is an enlarged view of a region similar to region X in FIG. 2 of the disposable diaper 1 according to the third embodiment of the invention. FIG. 6 is an enlarged view of a region similar to region X in FIG. 2 of the disposable diaper 1 according to the fourth embodiment of the invention. FIG. 7 is an enlarged view of a region similar to region X in FIG. 2 of the disposable diaper 1 according to the fifth embodiment of the invention.

Hereinafter, embodiments of the present disclosure will be described in detail. It should be noted that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the disclosure. Hereinafter, the absorbent article of the present invention will be described in detail using an embodiment applied to a disposable diaper, which is an example of the absorbent article. In this specification, unless otherwise specified, in the thickness direction of the absorbent article, "when the absorbent article is worn, the relatively proximal side with respect to the wearer's skin surface" is defined as the "skin-facing surface." The "non-skin facing side" refers to the "distal side relative to the wearer's skin surface when the absorbent article is worn". In the present invention, the lamination direction of the absorbent article means the direction in which the layers constituting the absorbent article are laminated in the unfolded state of the absorbent article.

《Absorbent article》
The absorbent article of the present invention has a top sheet layer, an absorbent layer, an indicator layer, and a leak-proof layer in this order, and the absorbent layer comprises an absorbent core layer and at least the leak-proof layer side of the absorbent core layer. It has an overlying core wrap layer. The indicator layer is adjusted to an alkaline appearance color in an initial state before contact with urine, is capable of changing color to a color corresponding to the specific gravity of urine upon contact with urine, and is at least partially composed of a core wrap layer and a leak-proof layer. and are positioned between them.

Here, "directly bonded" means that the indicator layer and the leakproof layer, and the indicator layer and the core wrap layer are in direct physical contact without intervening another layer, such as an adhesive layer. means connected.

Further, the expression that the indicator layer is "disposed between" the leak-proof layer and the core wrap layer means that the core wrap layer, the indicator layer, and the leak-proof layer are arranged in this order when the absorbent article is viewed from the stacking direction. means a configuration having a portion that is Accordingly, a portion of the indicator layer may penetrate the core wrap layer and/or the leak barrier layer. Here, part of the portion of the indicator layer that has entered the core wrap layer and/or the leak-proof layer is located on the opposite side of the core wrap layer and/or the leak-proof layer (the skin-facing side of the core wrap layer and/or the leak-proof layer (Non-skin-facing surface side), it is understood that the indicator layer is arranged between the core wrap layer and the leak-proof layer.

In the absorbent article of the present invention, the indicator layer can change color depending on urine specific gravity. More specifically, unlike the color change for detecting the presence or absence of urination (i.e., the color change of the pH indicator in the indicator from the acidic color to the alkaline color), depending on the urine specific gravity (i.e., urine Depending on the concentration of ions such as sodium ions (Na ⁺ ), potassium ions (K ⁺ ), calcium ions (Ca ²⁺ ), magnesium ions (Mg ²⁺ ), etc.), the appearance color changes from the alkaline side, so disposable diapers, etc. When applied to the absorbent article, the wearer of the absorbent article or its assistant can easily recognize the change in the urine specific gravity.

An absorbent article using such an indicator layer is required to have high visibility from the viewpoint of more accurately confirming discoloration. In addition, the color change according to the urine specific gravity is useful for grasping the state of the wearer's body, such as the degree of growth and the presence or absence of dehydration. , should be done more quickly.

In the absorbent article of the present invention, the indicator layer is directly bonded to and disposed between the core wrap layer and the leakproof layer.

If the indicator layer is directly joined to the core wrap layer, the urine retained by the core wrap layer easily flows into the indicator layer through the joint. Therefore, the indicator layer discolors more quickly than when the indicator layer is not directly bonded to the core wrap layer. Therefore, responsiveness can be improved.

Also, when the indicator layer is directly bonded to the leak-proof layer, the indicator layer is easier to visually recognize from the leak-proof layer side than when the indicator layer is not directly bonded to the leak-proof layer.

That is, the absorbent article of the present invention has high visibility and responsiveness.

FIG. 1 is a schematic diagram of a disposable diaper 1 according to a first embodiment of the invention. 2 is an enlarged cross-sectional view of the disposable diaper 1 of FIG. 1 taken along the line II--II. In addition, FIG.1 and FIG.2 is not the meaning which limits the absorbent article of this invention.

As shown in FIG. 1 , the disposable diaper 1 has a front portion located on the lower abdomen of the wearer when worn, a rear portion located on the buttocks of the wearer when worn, and a front portion positioned between the front portion and the rear portion. a middle portion positioned at the crotch portion of the wearer when worn. The disposable diaper 1 is formed by the upper end portion of the front portion and the upper end portion of the rear portion by joining both the left and right ends of the front portion and the left and right ends of the rear portion. It has a pants-type external shape with a waist opening and a pair of leg openings formed on both sides in the left-right direction of the intermediate portion. That is, the disposable diaper 1 is a so-called pants-type disposable diaper.

As shown in FIG. 2, the disposable diaper 1 comprises a top sheet layer 2, an absorbent layer 4, an indicator layer 5, and a top sheet layer 2, an absorbent layer 4, an indicator layer 5, in this order from the skin-facing side to the non-skin-facing side, as in a conventional disposable diaper. and a leak-proof layer 3 in this order. The absorbent layer 4 has an absorbent core layer 4a and a core wrap layer 4b covering at least the leakproof layer 3 side of the absorbent core layer 4a (in FIG. 2, the entirety is covered). The indicator layer 5 is adjusted to an alkaline appearance color in the initial state before coming into contact with urine, is capable of changing color to a color corresponding to urine specific gravity when coming into contact with urine, and is at least partially separated from the core wrap layer 4b. It is directly joined to the leakage layer 3 and arranged between them.

The absorbent article of the present invention is not particularly limited as long as it is an absorbent article that absorbs at least urine, and in addition to pants-type disposable diapers, for example, various absorbents such as tape-type disposable diapers and incontinence pads. It can be applied to goods.

For example, when the indicator of the present invention is applied to disposable diapers for toilet training of infants, by appropriately visualizing changes in the specific gravity of urine excreted from the infant, the infant's body is ready for potty training. It has the advantage of being able to estimate whether or not That is, the absorbent article of the present invention is preferably for toilet training.

In addition, when the indicator of the present invention is applied to disposable diapers for adults, by appropriately visualizing changes in the specific gravity of urine excreted from adult wearers such as care recipients, it is possible to predict dehydration symptoms. has the advantage of being able to detect

In addition, the absorbent article of the present invention may have a colored portion serving as a color sample of color change of urine specific gravity from the viewpoint of facilitating determination of color change of the indicator layer according to urine specific gravity.

The colored portion is preferably arranged on the non-skin-facing side of the leak-proof layer, that is, on the opposite side of the indicator layer with respect to the leak-proof layer when the absorbent article is viewed from the stacking direction. As a result, the color of the colored portion and the discoloration of the indicator layer can be approximated, and the discoloration of the indicator layer according to the urine specific gravity can be observed more accurately.

In addition, it is preferable that the colored portion is spaced apart from the indicator layer with respect to the surface direction of the absorbent article in the unfolded state. As a result, the discoloration of the indicator layer and the colored portion can be clearly distinguished.

The degree of discoloration of the indicator layer may be determined by the naked eye, or may be determined by optically measured reflectance or the like. When determining the degree of discoloration with the naked eye, for example, the color tone of the indicator can be determined by comparing the color tone of a standard color tone table (that is, a color sample) created in advance with the naked eye. In addition, when determining the degree of discoloration by optical measurement, for example, an image of the indicator taken by a photographing means such as a digital camera or a smartphone may be processed with an image processing program installed on any computer or smartphone. can be determined by

<Top sheet layer>
The top sheet layer is arranged on the skin-facing surface side in the thickness direction of the absorbent article and forms a contact surface that can come into contact with the wearer's skin, that is, the surface of the absorbent article on the skin-facing side. and is formed of a liquid-permeable sheet-like member such as a nonwoven fabric. The outer shape, various dimensions, basis weight, etc. of the top sheet layer are not particularly limited as long as they can be used as the top sheet layer of the absorbent article, and are selected according to the desired liquid permeability, touch, flexibility, strength, etc. Any external shape, various dimensions, basis weight, etc. can be adopted.

<Absorber layer>
The absorbent layer has an absorbent core layer and a core wrap layer covering at least the leakproof layer side of the absorbent core layer.

The outer shape, various dimensions, basis weight, etc. of the absorbent layer are not particularly limited as long as it can be used as the absorbent layer of the absorbent article, and any outer shape according to the desired water absorption, flexibility, strength, etc. A shape, various dimensions, basis weight, etc. can be adopted.

(Absorptive core layer)
The absorbent core layer may consist of an absorbent material including at least one of water-absorbent fibers and superabsorbent polymers. Here, as the water-absorbing fibers, for example, pulp fibers (for example, pulverized pulp), cotton, rayon, cellulosic fibers such as acetate, and the like can be used. Further, as the superabsorbent polymer, for example, starch-based superabsorbent polymers; granular materials such as synthetic polymer-based superabsorbent polymers (so-called “SAP”) such as sodium acrylate copolymers can be used.

When the absorbent article is viewed from the stacking direction, the absorbent core layer preferably has a higher density in at least a portion of the region overlapping the indicator layer than in other regions of the absorbent core layer.

A portion of the absorbent core layer having a higher density than other regions of the absorbent core layer may be, for example, an embossment applied to the absorbent core layer.

In the vicinity of the high-density region of the absorbent core layer, urine easily moves along the high-density portion, so urine moves faster in the thickness direction than in the other portions of the absorbent core layer. Therefore, when the absorbent core layer has a high-density region, when the wearer urinates, urine tends to move to the indicator layer more quickly than when the absorbent core layer does not have a high-density region.

FIG. 3 is an enlarged view of region X in FIG. In addition, FIG. 3 is not intended to limit the absorbent article of the present invention.

As shown in FIG. 3, the absorbent core layer 4a of the disposable diaper 1 according to the first embodiment of the present invention has a portion having a higher density than other regions of the absorbent core layer 4a, i.e., a high density region 41. ing. The high density region 41 overlaps at least a portion of the region overlapping the indicator layer 5 when viewed in the stacking direction.

(core wrap layer)
The core wrap layer is a hydrophilic layer covering at least the leak-proof layer side of the absorbent core layer. The core wrap layer can be formed of, for example, an SMS nonwoven fabric, an SB nonwoven fabric, a spunlaced nonwoven fabric, or a tissue sheet (pulp fiber). The core wrap layer may cover at least the leak-proof layer side of the absorbent core layer, but may cover the entire surface of the absorbent core layer, for example.

<Indicator layer>
The indicator layer is adjusted to an alkaline appearance color in an initial state before contact with urine, is capable of changing color to a color corresponding to the specific gravity of urine upon contact with urine, and is at least partially combined with the core wrap layer and the leakproof layer. directly bonded to and positioned between the layers.

The indicator layer may contain a thermoplastic component with a melting point or softening point within the range of 40°C to 120°C. Here, the "softening point" and the "melting point" respectively refer to the "endothermic onset temperature" when measuring the endothermic behavior of changing from a solid state to a liquid state with a differential scanning calorimeter at a heating rate of 10°C/min. ” and “peak top temperature”. Specific components will be described in <Indicator composition> below.

When the indicator layer contains a thermoplastic component having a melting point or softening point within such a range, for example, when the absorbent article is manufactured, the indicator layer is applied to the leak-proof layer at the melting point or softening point. The absorbent article of aspect 1 can be readily formed by placing and optionally pressing a core wrap layer over the indicator layer before the indicator layer solidifies.

Furthermore, absorbent articles are typically used at temperatures below 40°C, for example around 36°C, which is the typical body temperature of the wearer. Therefore, the indicator layer is less likely to be deformed by temperature during use, and, for example, the bonding between the indicator layer and the core wrap layer and the leak-proof layer is less likely to be destroyed by the action of the wearer.

Thereby, high productivity and durability can be obtained while realizing high visibility and responsiveness.

Also, the indicator layer may further contain at least one of a hydrophilic polymer and an amine cationic surfactant. Specific hydrophilic polymers and amine-based cationic surfactants will be described in <Indicator composition> below.

When the indicator layer further contains at least one of a hydrophilic polymer and an amine-based cationic surfactant, the indicator layer is highly responsive to changes in urine specific gravity when the indicator layer comes into contact with urine, Even when the amount of change in urine specific gravity is small, the color can be clearly changed.

The indicator layer can also contain liquid components that are liquid at 36°C. Specific components are described in <<Indicator composition>> below.

Also, the indicator layer can turn blue or green when in contact with low specific gravity urine and turn yellow or orange when in contact with high specific gravity urine. A configuration for exhibiting such a color change will also be described in the following «Indicator composition».

Unlike the color change for detecting the presence or absence of urination (that is, the color change from acidic color to alkaline color), the indicator layer changes color to blue or green when it comes into contact with low-specific-gravity urine. If it changes color to yellow or orange when it comes into contact with urine, when it is applied to an absorbent article such as a disposable diaper, the wearer of the absorbent article or an assistant can easily recognize the change in urine specific gravity. The color change from the initial color before contact with urine to yellow or orange when it comes into contact with high specific gravity urine is easier to see. As a result, changes in urine specific gravity can be detected more accurately and easily.

Note that the description of <<indicator composition>> below merely exemplifies materials that can be formed in the indicator layer of the absorbent article of the present invention, and the indicator layer of the absorbent article of the present invention is Materials to be formed are not limited to these.

(core wrap layer impregnated part)
Preferably, the indicator layer has a core wrap layer impregnated portion that is recessed into the core wrap layer.

When the indicator layer has the core wrap layer-impregnated portion, urine tends to move throughout the indicator layer along the core wrap layer-impregnated portion within the core wrap layer. That is, the core wrap layer-impregnated portion functions as a path for urine flowing from the absorbent core layer to the core wrap layer to reach the entire indicator layer through the core wrap layer when the wearer urinates. As a result, in the core wrap layer, urine can easily move through the core wrap layer-impregnated portion to the entire indicator layer.

Here, the expression that the indicator layer is "incorporated" into the core wrap layer means that, of the indicator composition that constitutes the indicator layer, a solid component, for example, a thermoplastic component described in <<Indicator Composition>> below, is included in the core wrap. Denotes the state that exists within a layer. Note that the core wrap layer impregnated portion is continuous with other portions of the indicator layer.

The presence or absence of the core wrap layer-impregnated portion can be known, for example, by observing a cross section of the absorbent article in the stacking direction with an electron microscope or the like.

The area of the core wrap layer-impregnated portion is preferably 20.0% or more of the area of the indicator layer when the absorbent article is viewed from the stacking direction.

When the area of the core wrap layer-impregnated portion is 20.0% or more of the area of the indicator layer, urine particularly easily moves through the core wrap layer-impregnated portion to the entire indicator layer in the core wrap layer. This makes it possible to achieve even higher responsiveness.

Further, when the absorbent article is viewed from the stacking direction, the area of the core wrap layer-impregnated portion may be 30.0% or more and 95.0% or less of the area of the indicator layer. This percentage may be 20.0% or more, 30.0% or more, 40.0% or more, or 50.0% or more, and 95.0% or less, 75.0% or less, or 65.0% may be:

FIG. 4 is an enlarged view of a region similar to region X in FIG. 2 of the disposable diaper 1 according to the second embodiment of the invention. In addition, FIG. 4 is not intended to limit the absorbent article of the present invention.

As shown in FIG. 4, in the disposable diaper 1 according to the second embodiment of the present invention, the indicator layer 5 has a core wrap layer impregnated portion 52 that is embedded in the core wrap layer 4b.

Moreover, it is preferable that the core wrap layer-impregnated portion partially reaches the surface of the core wrap layer facing the absorbent core layer and is in contact with the absorbent core layer.

Such a configuration allows urine absorbed by the absorbent core layer to come into direct contact with the indicator layer. Therefore, the urine absorbed by the absorbent core layer can be diffused over the entire indicator layer more quickly, and a higher responsiveness can be achieved.

The ratio of the area of the core wrap layer-impregnated portion when viewed from the stacking direction of the absorbent article to the area of the indicator layer can be measured, for example, by the following methods (1) to (5):
(1) A sample in which the core wrap layer, the indicator layer, and the leakproof layer are integrated is taken out from the absorbent article, and the area where the indicator layer exists is specified (for example, the indicator layer is applied with a width of 6 mm × length of 100 mm a 6 mm wide by 50 mm long area in the longitudinal central portion of the sample). Let this area be a measurement target area.
(2) Peel off the core wrap layer from the absorbent article. The peeled core wrap layer is also peeled from both the absorbent core layer and the indicator layer.
(3) With the indicator layer side of the core wrap layer facing upward, the core wrap layer is placed on a standard white plate, and an image including the measurement target area is photographed with a digital camera. * Shoot under normal indoor lighting conditions, and be careful not to include shadows or reflected light.
(4) For the photographed image, adjust the white balance in the photographing area, and set the value of H (hue) in the HSV color space of the material constituting the core wrap layer (the area that does not overlap with the indicator layer) to a range of 40 to 70. within
(5) Next, in the measurement target area, the area of the part where the value of H (color layer) is 100 or more is measured, and the value obtained by dividing by the area of the entire measurement target area is the absorbent article with respect to the area of the indicator layer. is the ratio of the area of the impregnated portion of the core wrap layer viewed from the stacking direction.

Here, when the absorbent article is viewed from the stacking direction, the area of the portion of the core wrap layer-impregnated portion that reaches the absorbent core layer side is 50.0% or less of the area of the indicator layer. preferable.

When the area of the portion of the core wrap layer-impregnated portion that reaches the absorbent core layer side surface is within the above range, the urine that reaches the indicator layer from the core wrap layer-impregnated portion along the absorbent core layer side of the core wrap layer reaches the indicator layer. However, the urine is easily diffused in the surface direction by the core wrap layer in the vicinity of the portion of the indicator layer on the core wrap layer side, and the urine is particularly likely to move to the entire indicator layer.

This makes it possible to achieve even higher responsiveness.

When the absorbent article is viewed from the stacking direction, the area of the portion of the core wrap layer impregnated portion that reaches the absorbent core layer side is 50.0% or less and 0.2% or more of the area of the indicator layer. is particularly preferred.

When the area of the portion of the core wrap layer-impregnated portion that reaches the absorbent core layer side surface is 50% or less, the urine that reaches the indicator layer from the core wrap layer-impregnated portion along the absorbent core layer side, The width diffused in the plane direction by the core wrap layer is particularly large in the vicinity of the portion of the indicator layer on the core wrap layer side. On the other hand, when the area of the portion of the core wrap layer-impregnated portion that reaches the absorbent core layer side surface is 0.2% or more, urine flows from the absorbent core layer side of the core wrap layer through the core wrap layer-impregnated portion and into the indicator layer. A path is sufficiently formed to reach the

The area of the portion of the core wrap layer impregnated portion that reaches the absorbent core layer side may be 50.0% or less, 20.0% or less, or 5.0% or less of the area of the indicator layer, and 0 0.2% or more, 0.5% or more, or 1.0% or more.

The ratio of the area of the portion of the core wrap layer impregnated portion that reaches the absorbent core layer side to the area of the indicator layer can be measured, for example, by the methods shown in (1) to (5) below. can:
(1) A sample in which the core wrap layer, the indicator layer, and the leakproof layer are integrated is taken out from the absorbent article, and the area where the indicator layer exists is specified (for example, the indicator layer is applied with a width of 6 mm × length of 100 mm a 6 mm wide by 50 mm long area in the longitudinal central portion of the sample). Let this area be a measurement target area.
(2) Peel off the core wrap layer from the absorbent article. The peeled core wrap layer is also peeled from both the absorbent core layer and the indicator layer.
(3) With the absorbent core layer side of the core wrap layer facing upward, place the core wrap layer on the standard white plate, and take an image including the measurement target area with a digital camera. * Shoot under normal indoor lighting conditions, and be careful not to include shadows or reflected light.
(4) For the photographed image, adjust the white balance in the photographing area, and set the value of H (hue) in the HSV color space of the material constituting the core wrap layer (the area that does not overlap with the indicator layer) to a range of 40 to 70. within
(5) Next, in the measurement target area, the area of the part where the value of H (color layer) is 100 or more is measured, and the value obtained by dividing by the area of the entire measurement target area is the absorbent article with respect to the area of the indicator layer. is the ratio of the area of the impregnated portion of the core wrap layer viewed from the stacking direction.

FIG. 5 is an enlarged view of a region similar to region X in FIG. 2 of the disposable diaper 1 according to the third embodiment of the invention. In addition, FIG. 5 is not intended to limit the absorbent article of the present invention.

As shown in FIG. 5, in the disposable diaper 1 according to the third embodiment of the present invention, the core wrap layer-impregnated portion 52 partially reaches the surface of the core wrap layer 4b on the side of the absorbent core layer 4a, and It is in contact with layer 4a.

(leakproof layer impregnated part)
If the leak-proof layer is a layer of hydrophobic non-woven fabric, the indicator layer preferably has a leak-proof layer-impregnated portion that is embedded in the leak-proof layer.

When the leak-proof layer is a hydrophobic non-woven fabric layer, it is possible to release volatile components in urine, such as water vapor, while suppressing leakage of liquid in urine to the opposite side of the leak-proof layer. However, hydrophobic nonwoven layers typically tend to have lower visible light transmission than non-porous layers due to the difference in refractive index between the air in the voids of the nonwoven and the material forming the leakproof layer. It is in. When the indicator layer enters the leak-proof layer, the thickness of only the leak-proof layer that does not enter the indicator layer is reduced when viewed from the non-skin facing side of the absorbent article, thereby reducing the thickness of the indicator layer. High visibility.

Here, the expression that the indicator layer is "incorporated" into the leak-proof layer means that the indicator composition constituting the indicator layer contains a solid component, for example, a thermoplastic component described in <<Indicator Composition>> below. It means the state existing within the leakproof layer. The leak-proof layer-impregnated portion is continuous with other portions of the indicator layer.

The presence or absence of the leak-proof layer-impregnated portion can be known, for example, by observing a cross section of the absorbent article in the stacking direction with an electron microscope or the like.

FIG. 6 is an enlarged view of a region similar to region X in FIG. 2 of the disposable diaper 1 according to the fourth embodiment of the invention. In addition, FIG. 6 is not intended to limit the absorbent article of the present invention.

As shown in FIG. 6 , in the disposable diaper 1 according to the fourth embodiment of the present invention, the indicator layer 5 has a leak-barrier layer-impregnated portion 53 that enters the leak-barrier layer 3 .

(Non-impregnated part)
The indicator layer preferably has a non-impregnated portion that is impregnated in neither the core wrap layer nor the leak-proof layer.

As described above, the non-impregnated portion of the indicator layer has a high density of components constituting the indicator layer. Therefore, the non-impregnated portion is more discolored by urine than the portion impregnated with the core wrap layer and the leak-proof layer.

The non-impregnated portion does not presuppose the presence of a portion where the indicator layer impregnates the core wrap layer and the leakproof layer, that is, the corewrap layer impregnated portion and/or the leakproof layer impregnated portion. That is, the indicator layer may be composed only of the non-impregnated portion. When the indicator layer has a core wrap layer impregnated portion and/or a leakproof layer impregnated portion, the non-impregnated portion is continuous with these portions.

From the viewpoint of improving reactivity, when the indicator layer has a core wrap layer-impregnated portion and/or a leak-proof layer-impregnated portion, the non-impregnated portion is preferably thicker than these layers with respect to the lamination direction of the absorbent article.

The presence or absence of non-impregnated portions can be known, for example, by observing a cross-section of the absorbent article in the stacking direction with an electron microscope or the like. The thicknesses of the non-impregnated portion, the core wrap layer impregnated portion, and the leakproof layer impregnated portion can also be compared, for example, by observing a cross section of the absorbent article in the stacking direction with an electron microscope or the like.

The non-impregnated portion is arranged between the core wrap layer and the leakproof layer, for example, in the manner shown in FIGS. 3-7.

<Leak-proof layer>
The leak-proof layer is arranged on the non-skin facing side in the thickness direction of the absorbent article, and forms the surface of the absorbent article on the non-skin facing side. It is formed of a liquid-impermeable sheet-like member such as a resin film or a hydrophobic nonwoven fabric that can prevent leakage of excrement such as urine excreted by the wearer of the absorbent article to the outside of the absorbent article. .

In the absorbent article of the present invention, when the indicator layer contains a liquid component that is liquid at 36°C, when the absorbent article is viewed from the stacking direction, the portion of the leak-proof layer that overlaps the indicator layer At least a portion of the liquid component preferably impregnates the leak-proof layer.

When the leak-proof layer is impregnated with the liquid component, the gap between the indicator layer and the leak-proof layer and the fine space inside the leak-proof layer are filled with the liquid component. Therefore, the visible light transmittance is higher than that of other portions of the anti-leakage layer by suppressing irregular reflection in the portion. Therefore, the discoloration of the indicator layer is more easily visible from the leak-proof layer side, that is, from the non-skin facing side of the absorbent article.

The mode of impregnation of the liquid component into the leak-proof layer is not particularly limited. The leak-proof layer can be impregnated by filling the pores of the nonwoven fabric or the voids of the nonwoven fabric. Moreover, when the leak-proof layer is a film having no pores, the liquid component can be impregnated by permeating the film.

FIG. 7 is an enlarged view of a region similar to region X in FIG. 2 of the disposable diaper 1 according to the fifth embodiment of the invention.

As shown in FIG. 7, in the disposable diaper 1 according to the fifth embodiment of the present invention, the leak-proof layer 3 is impregnated with the liquid component 51 in at least part of the portion of the leak-proof layer 3 that overlaps the indicator layer 5. are doing.

In addition, from the viewpoint of suppressing the visibility of feces and urine from the same side while improving the visibility of the discoloration of the indicator layer according to the urine specific gravity from the non-skin facing side of the absorbent article, the absorbent article is used. When viewed from the stacking direction, the layers on the leak-preventing layer side of the indicator layer have a total of 30.0% or more and 90.0% or less in the visible spectrum region at least in the region overlapping with the indicator layer. of visible light transmittance.

In addition, "a layer closer to the anti-leakage layer than the indicator layer" is synonymous with a layer closer to the non-skin-facing surface than the indicator layer of the absorbent article, and means, for example, a leakage-prevention layer. When the absorbent article of the present invention has other layers in addition to the leak-proof layer on the non-skin-facing side of the indicator layer, the "layer closer to the leak-proof layer than the indicator layer" is , means the leakproof layer and said layer together.

In addition, the visible light transmittance in the visible spectrum region is measured by peeling the layer closer to the anti-leakage layer than the indicator layer from the absorbent article and measuring the visible light transmittance in the thickness direction using a transmittance measuring instrument (Nippon Denshoku Industries Co., Ltd.). It can be obtained by measuring with a company's illumination side light color difference meter A300/ZE-2000 type).

<Back sheet layer>
The absorbent article of the present invention can further have a back sheet layer on the opposite side of the leak-proof layer to the indicator layer, that is, on the non-skin facing side. In this case, the back sheet layer forms the non-skin-facing surface of the absorbent article instead of the leak-proof layer. The back sheet layer has such a visible light transmittance that the discoloration of the indicator layer can be visually recognized when the absorbent article is viewed from the non-skin facing side.

From the viewpoint of improving the visibility of the indicator layer, when the absorbent article is viewed from the stacking direction, the basis weight of at least a portion of the region overlapping the indicator layer of the backsheet layer is higher than that of the other portions of the backsheet layer. Small is preferred.

<<Indicator composition>>
The indicator composition of the present invention is adjusted to an alkaline appearance color in the initial state before contact with urine, is capable of changing to a color corresponding to urine specific gravity upon contact with urine, and has a temperature range of 40°C to 120°C. An indicator composition containing a thermoplastic component having a melting or softening point within the range of .

As noted above, the indicator compositions of the present invention can be used to readily form absorbent articles of the present invention.

The indicator composition of the present disclosure is adjusted to an alkaline appearance color in the initial state before contact with urine, and can change color depending on urine specific gravity upon contact with urine. The indicator composition of the present invention comprises, for example, a pH indicator, 20% by mass or more of an aliphatic alcohol that is solid at room temperature, 10% by mass or more of a hydrophilic polymer, and 10% by mass or more of an amine cationic interface. and at least one component of the active agent.

The indicator composition is adjusted to an alkaline appearance color in the initial state before contact with urine, but changes to an acidic appearance color upon contact with urine excreted from the wearer of the absorbent article. At this time, the indicator composition changes color to a different color according to the value of the specific gravity of the urine.

Regarding the color tone of the indicator composition, the appearance colors on the alkaline side and the acidic side are determined by the relative pH relationship before and after coloration due to contact with urine. It depends on the type of pH indicator used. For example, when bromothymol blue is used as the pH indicator, the appearance color on the alkaline side is purple, blue or bluish green, and the appearance color on the acidic side is yellowish green, yellow or orange. Unlike the conventional color change for detecting the presence or absence of urination (that is, the color change of the pH indicator in the indicator composition from the acidic color to the alkaline color), the indicator composition of the present invention is different from the urine specific gravity. Therefore, when applied to absorbent articles such as disposable diapers, the wearer of the absorbent article or its assistant can easily recognize the change in urine specific gravity. Become.

The indicator composition of the present invention preferably turns blue or green when it comes into contact with urine of low specific gravity, and turns yellow or orange when it comes into contact with urine of high specific gravity. Such an indicator composition, unlike the color change for detecting the presence or absence of urination, that is, the color change of the pH indicator in the indicator composition from the acidic color to the alkaline color, when it comes into contact with low specific gravity urine. It changes color to blue or green, and changes to yellow or orange when it comes into contact with urine having a high specific gravity. In particular, the color change from the initial color before contact with urine to yellow or orange upon contact with urine having a high specific gravity becomes more visible. Accordingly, such an indicator composition can more accurately and easily detect changes in urine specific gravity.

Here, the means for adjusting the appearance color of the indicator composition in the initial state before coming into contact with urine to an alkaline appearance color is not particularly limited. alkalinizing agent (for example, some pH adjusting agents such as bases, salts, buffering agents, etc.).

<pH indicator>
The indicator composition of the invention can contain a pH indicator. The pH indicator is not particularly limited as long as it can be used in indicator compositions for absorbent articles, but a pH indicator whose dissociation is promoted by an increase in ionic strength is preferred. Specific examples of such pH indicators include bromothymol blue (BTB), gentian violet, bromocresol purple, malachite green, thymol blue, methyl yellow, bromophenol blue, congo red, methyl orange, litmus, phenol red. , chlorophenol red, neutral red, bromocresol green, methyl red, naphtholphthalein, cresol red, cresolphthalein, phenolphthalein, thymolphthalein, and alizarin yellow R. One pH indicator may be used alone, or two or more pH indicators may be used in combination.

Preferred pH indicators include bromothymol blue (BTB), bromocresol purple, thymol blue, phenol red, chlorophenol red, bromocresol green and methyl red. These pH indicators are preferred because increased ionic strength promotes dissociation.

The indicator composition of the present invention preferably contains two or more pH indicators as pH indicators. By using a combination of two or more types of pH indicators, even urine with a smaller specific gravity difference can be clearly discolored, so changes in urine specific gravity can be detected more accurately and reliably. In addition, by combining two or more types of pH indicators with different color change ranges, it is possible to widen the detection range of urine specific gravity, increase the degree of color change due to changes in urine specific gravity, and make it easier to see.

When two or more types of pH indicators are used in combination as pH indicators, a combination of bromothymol blue and other pH indicators is preferred. When such a combination is used as a pH indicator, there is an advantage that the change in color tone can be increased and the color change range can be expanded. Other pH indicators that can be used in combination with bromothymol blue include, for example, thymol blue, phenol red and methyl red. Among these pH indicators, it is preferable to use methyl red. A combination of bromothymol blue and methyl red can realize a stable and wide-ranging color change (color reaction).

The content of the pH indicator contained in the indicator composition is not particularly limited, and can be appropriately set in consideration of the responsiveness of the color reaction, visibility, and the like. Such a content is, for example, from 0.01% by mass to 10.0% by mass, preferably from 0.01% by mass to the total mass (100% by mass) of the indicator composition composition. 5.0% by mass, more preferably 0.05% to 4.0% by mass. When the content of the pH indicator is within such a range, good visibility of the response (coloration) of the indicator composition can be ensured.

<Thermoplastic component>
The indicator composition of the present invention contains a thermoplastic component with a melting point or softening point within the range of 40°C to 120°C. The thermoplastic component may be, for example, a fatty alcohol.

(fatty alcohol)
The indicator composition of the present invention can contain an aliphatic alcohol that is solid at room temperature (20° C.) in a content of 20% by mass or more relative to the total mass (100% by mass) of the indicator composition. Containing such a specific aliphatic alcohol makes the indicator composition less soluble in water such as urine and humidity.

The aliphatic alcohol that can be used in the indicator composition of the present invention is not particularly limited as long as it is solid at room temperature and can be used in the indicator composition for absorbent articles. C8 to C34) aliphatic alcohols, and the like. As for the fatty alcohol, one type of fatty alcohol may be used alone, or two or more types of fatty alcohol may be used in combination.

Preferred fatty alcohols include fatty alcohols having a melting point or softening point above 40° C. and below 120° C. Specific examples include 1-hexadecanol, 1-octadecanol, 1-eicosanol. , 1-docosanol, 1-tetracosanol, 1-hexacosanol, 1-octacosanol and the like. When the aliphatic alcohol contained in the indicator composition has such a specific melting point or softening point, the indicator composition composition is applied in a molten state to a substrate such as a nonwoven fabric or a film, and then cooled. Solidification proceeds and the indicator composition can be uniformly formed in precise locations on the substrate. As a result, when the indicator composition containing the above-mentioned specific aliphatic alcohol comes into contact with sodium ions (Na ⁺ ), potassium ions (K ⁺ ), calcium ions (Ca ²⁺ ), and magnesium ions (Mg ²⁺ ) in urine, In addition, even if the color change is small, the color change can be easily visually recognized, so that the change in urine specific gravity can be detected more accurately and reliably.

The content of the aliphatic alcohol contained in the indicator composition is not particularly limited as long as it is 20% by mass or more with respect to the total mass (100% by mass) of the indicator composition, and it does not dissolve in moisture such as urine and moisture. It can be appropriately set in consideration of the difficulty of doing so, visibility, and the like. Such a content is, for example, 20% by mass to 80% by mass, preferably 30% by mass to 60% by mass, relative to the total mass (100% by mass) of the indicator composition composition.

<Hydrophilic polymer>
The indicator composition of the present invention can contain at least one component of 10% by mass or more of a hydrophilic polymer and 10% by mass or more of an amine-based cationic surfactant. By containing a predetermined amount of such a component, the indicator composition has a high responsiveness of color change to changes in urine specific gravity when it comes into contact with urine, and even when the amount of change in urine specific gravity is small, the indicator composition clearly changes color. be able to.

The hydrophilic polymer that can be used in the indicator composition of the present invention is not particularly limited as long as it is a polymer having hydrophilicity. (e.g., polyacrylic acid, polyacrylamide, maleic anhydride polymer, etc.), polyol (e.g., polyethylene glycol, etc.), polyvinylpyrrolidone, polyvinyl alcohol, polyallylamine, polyethyleneimine, oxazoline-based polymer (e.g., poly(2-oxazoline) , poly(2-ethyl-2-oxazoline), poly(2-methyl-2-oxazoline), etc.). As the hydrophilic polymer, one kind of hydrophilic polymer may be used alone, or two or more kinds of hydrophilic polymers may be used in combination.

In this specification, in order to distinguish between the hydrophilic polymer and the sugar alcohol polymer of the sugar alcohol component described later, the hydrophilic polymer excludes the sugar alcohol polymer.

The indicator composition of the present invention preferably contains polyamide as the hydrophilic polymer. When the indicator composition contains a polyamide as a hydrophilic polymer, it acts on the shape change of the pH indicator, widens the color change range of the urine specific gravity, has a strong dissolving action, and increases the response speed. As a result, an indicator composition containing a polyamide as a hydrophilic polymer can accurately detect a wide range of changes in urine specific gravity. The polyamide preferably has a softening point of 140° C. or lower.

The content of the hydrophilic polymer contained in the indicator composition is not particularly limited as long as it is 10% by mass or more with respect to the total mass (100% by mass) of the indicator composition, and the responsiveness of the color reaction and visual recognition It can be appropriately set in consideration of the nature and the like. Such a content is, for example, 10% by mass to 40% by mass, preferably 15% by mass to 30% by mass, relative to the total mass (100% by mass) of the indicator composition composition.

<Amine cationic surfactant>
The amine-based cationic surfactant that can be used in the indicator composition of the present invention is not particularly limited as long as it is an amine-based surfactant having a cationic hydrophilic group. cationic surfactants, alkylamine salt-type surfactants, and cationic surfactants having a pyridine ring.

Specific examples of quaternary ammonium salt-type cationic surfactants include tetramethylammonium chloride, tetramethylammonium hydroxide, tetrabutylammonium chloride, dodecyldimethylbenzylammonium chloride, alkyltrimethylammonium chloride, and octyltrimethyl chloride. ammonium, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, alkyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, benzyltrimethylammonium chloride, benzyltriethylammonium chloride , benzalkonium chloride, benzalkonium bromide, benzethonium chloride, dialkyldimethylammonium chloride, didecyldimethylammonium chloride and distearyldimethylammonium chloride.

Specific examples of alkylamine salt-type cationic surfactants include monomethylamine hydrochloride, dimethylamine hydrochloride and trimethylamine hydrochloride.

Specific examples of cationic surfactants having a pyridine ring include butylpyridinium chloride, dodecylpyridinium chloride and cetylpyridinium chloride.

As for the above cationic surfactants, one type of cationic surfactant may be used alone, or two or more types of cationic surfactants may be used in combination.

The indicator composition of the present invention preferably contains a quaternary ammonium salt as an amine cationic surfactant. When the amine-based cationic surfactant contains a quaternary ammonium salt, it has a high surfactant activity, and the color change speed becomes faster when the indicator composition comes into contact with urine. As a result, the indicator composition containing a quaternary ammonium salt as a cationic surfactant can more accurately detect changes in urine specific gravity.

The content of the cationic surfactant contained in the indicator composition is not particularly limited as long as it is 10% by mass or more with respect to the total mass (100% by mass) of the indicator composition. It can be appropriately set in consideration of visibility and the like. Such a content is, for example, 10% by mass to 40% by mass, preferably 15% by mass to 30% by mass, relative to the total mass (100% by mass) of the indicator composition composition.

<Sugar alcohol component>
The indicator composition of the present invention may further optionally contain a sugar alcohol component. Preferably, the indicator composition of the present invention further contains at least one of sugar alcohols and sugar alcohol polymers at a blending ratio of 2.5% by mass or more as the sugar alcohol component. The sugar alcohol component in the indicator composition of the present invention can increase the hydrophilicity of the indicator composition when it contains such a sugar alcohol component, and can increase the rate of discoloration upon contact with urine.

Sugar alcohol components that can be used in the indicator composition of the present invention include sugar alcohols and polymers thereof. Specifically, glycerin, erythritol, D-threitol, L-threitol, D-arabinitol, L- Examples thereof include sugar alcohols such as arabinitol, xylitol, ribitol, D-iditol, galactitol, mannitol, boremitol and perseitol, and polymers of these sugar alcohols. Preferred sugar alcohol components include, for example, glycerin. In addition, these sugar-alcohol components may be used individually by one type of sugar-alcohol component, and may use two or more types of sugar-alcohol components together.

The content of the sugar alcohol component contained in the indicator composition is not particularly limited as long as it is 2.5% by mass or more relative to the total mass (100% by mass) of the indicator composition. It can be appropriately set in consideration of visibility and the like. Such a content is, for example, 2.5% by mass to 20% by mass, preferably 3.0% by mass to 15.0% by mass, relative to the total mass (100% by mass) of the indicator composition composition. It is 0% by mass.

<Liquid component>
The indicator composition of the present invention can contain liquid components that are liquid at 36°C. Examples of such liquid components include liquid components such as waxes and oils. A liquid component can be included in the indicator composition as a plasticizer or tackifier. The indicator composition of the present invention preferably further contains at least one of wax and oil as a liquid component. In the indicator composition of the present invention, if the indicator composition contains such a liquid component, when the indicator composition composition is applied to a substrate such as a nonwoven fabric or a film, the fixability to the substrate is poor. This allows the indicator composition to be precisely formed in place on the substrate. As a result, the indicator composition containing such a hydrophobic component can more accurately and reliably detect changes in urine specific gravity. The liquid component may be a hydrophobic liquid component. Also, the liquid component may be a hydrophilic liquid component.

The wax that can be used in the indicator composition of the present invention is not particularly limited as long as it can act as a plasticizer, and examples thereof include known natural waxes and synthetic waxes. Specific examples of natural waxes include petroleum-derived waxes such as paraffin and microcrystalline wax (microcrystalline wax); animal-derived waxes such as beeswax and spermaceti; plant-derived waxes such as carnauba wax; and waxes derived from minerals. Specific examples of synthetic waxes include polyethylene waxes, Fischer-Tropsch waxes, fatty acid amides, and the like. Preferred waxes include petroleum-derived waxes such as paraffin and microcrystalline waxes.

The oil that can be used in the indicator composition of the present invention is not particularly limited as long as it can act as a plasticizer, and examples thereof include known paraffinic oils, naphthenic oils, and aromatic oils. Preferred oils include naphthenic oils.

As for the above liquid components, one type of liquid component may be used alone, or two or more types of liquid components may be used in combination.

The content of the liquid component contained in the indicator composition is not particularly limited as long as it does not inhibit the effects of the present invention. 30.0% by mass, preferably 1.0% to 20.0% by mass.

<Tackifying resin>
The indicator composition of the invention may contain a tackifying resin. The tackifier resin is not particularly limited as long as it can act as a tackifier, and examples thereof include known natural resins and petroleum-based resins. Specific examples of natural resins include plant-derived resins such as rosin and rosin derivatives, terpenes and modified terpenes. Specific examples of petroleum-based resins include C5-C9 aliphatic or aromatic resins, C5-C9 aliphatic and aromatic copolymer resins, and the like.

<Alkalizing agent>
The indicator composition of the invention can further comprise an alkalinizing agent. By containing such an alkalizing agent, the indicator composition is less likely to cause unevenness in color tone before and after coloration due to contact with urine, and the change in color is more easily visible.

In the indicator composition, the alkalinizing agent is also used as a means for adjusting the appearance color of the indicator composition in the initial state before contact with urine to the alkaline side.

The alkalinizing agent that can be used in the indicator composition of the present invention is not particularly limited, but for example, known sodium carbonate (Na ₂ CO ₃ ), sodium hydroxide (NaOH), potassium carbonate (K ₂ CO ₃ ), etc. mentioned.

The indicator composition of the present invention preferably further contains sodium carbonate as an alkalinizing agent. Compared to other alkalinizing agents such as sodium hydroxide and potassium carbonate, sodium carbonate mixes more uniformly with other components in the indicator composition. Even when the change in is small, the discoloration is easily visible. As a result, the indicator composition containing sodium carbonate as an alkalinizing agent can more accurately and reliably detect changes in urine specific gravity.

<Other additive ingredients>
The indicator composition of the present invention may further comprise any additive component that can be used in indicator compositions for absorbent articles. Examples of such additive components include, but are not particularly limited to, antioxidants, light stabilizers, antibacterial agents, fragrances, and the like.

The indicator composition composed of the above components is not particularly limited, but can be produced by mixing using any heating and melting means.

<<Examples 1 to 6 and Comparative Example 1>>
<Example 1>
1-docosanol as a thermoplastic component, a quaternary ammonium salt as an amine-based cationic surfactant, a polyamide having a softening point of about 120°C as a hydrophilic polymer, methyl red as a pH indicator and BTB, sodium carbonate as an alkalizing agent, glycerin as a sugar alcohol component, and naphthenic oil as a liquid component were mixed to obtain an indicator composition.

This indicator composition was then melted at 90° C. and applied to the surface of a polyethylene film as a leak-proof layer of a disposable diaper. Thereafter, before the indicator composition is cooled, an absorbent layer of a disposable diaper (absorbent core layer: superabsorbent polymer and pulp fibers, core wrap layer: SMS non-woven fabric with hydrophilic treatment) is placed on top of the indicator composition. It was laminated and pressed with a predetermined press pressure. Finally, the indicator composition is allowed to cool and solidify to produce the disposable diaper of Example 1, in which the indicator layer is positioned between the leakproof layer and the core wrap layer and directly bonded thereto. bottom.

<Examples 2 to 6>
Disposable diapers of Examples 1 to 6 were produced in the same manner as in Example 1, except that the melting temperature of the indicator composition was varied and the pressing pressure was varied. The melting temperature and pressing pressure of the indicator composition are as shown in Table 1.

<Comparative Example 1>
A disposable diaper of Comparative Example 1 was prepared in the same manner as in Example 1, except that the indicator composition was allowed to cool and solidify before laminating the absorbent layer over the indicator composition and no pressing was performed. manufactured. In the disposable diaper of Comparative Example 1, after the indicator composition was cooled and solidified to form the indicator layer, the core wrap layer was laminated on the indicator layer, so the indicator layer and the absorbent layer were not joined. rice field. The melting temperatures of the indicator compositions are shown in Table 1.

<Discoloration evaluation>
Urine having a urine specific gravity in the range of 1.000 to 1.040 is prepared, and after bringing the urine of each specific gravity into contact with the indicator composition used in the production of each example, whether or not the color change of the indicator can be identified is checked using a color sample. evaluated by comparison. Color change according to urine specific gravity was confirmed in urine of all urine specific gravities.

<Observation of transmittance of anti-leakage layer>
In the disposable diapers of Examples 1 to 6, the transparency of the portion of the leak-proof layer overlapping the indicator layer was higher than that of the disposable diaper of Comparative Example 1 when viewed from the stacking direction. This is because the naphthenic oil as the liquid component contained in the indicator layer impregnated the polyethylene film as the leak-proof layer.

<Discoloration speed evaluation>
Urine is dropped from the absorbent layer side of the disposable diaper and brought into contact with the indicator layer to be evaluated, and the color of the indicator layer after 3 minutes (color after discoloration due to urine) and the color of the indicator after 5 minutes. The color and the color of the indicator after 10 minutes had passed were compared from the leak-proof layer side using a color sample, and the identity of both colors was evaluated.

"◎" indicates that the color of the entire indicator layer has changed to the same color as the color sample, and "○" indicates that the indicator layer has partially changed color to the same color as the color sample. When the color was changed to the same color, it was rated as "Δ", and when the color change could not be confirmed, or the color was changed but it was difficult to determine whether it was the same color as the color sample, it was rated as "x".

The results are shown in Table 1 below.

<Area ratio measurement>
For the disposable diapers of each example, the area of the colored portion of the material constituting the indicator layer on the non-skin facing side and the skin facing side of the core wrap layer was measured by the following method.
(1) A sample in which the core wrap layer, the indicator layer, and the leakproof layer are integrated is taken out from the absorbent article, and the area where the indicator layer exists is specified (for example, the indicator layer is applied with a width of 6 mm × length of 100 mm a 6 mm wide by 50 mm long area in the longitudinal central portion of the sample). Let this area be a measurement target area.
(2) Peel off the core wrap layer from the absorbent article. The peeled core wrap layer is also peeled from both the absorbent core layer and the indicator layer.
(3) With the absorbent core layer side of the core wrap layer facing upward, place the core wrap layer on the standard white plate, and take an image including the measurement target area with a digital camera. Similarly, the indicator layer side of the core wrap layer is turned up, placed on the standard white plate, and an image including the measurement target area is photographed with a digital camera. * Shoot under normal indoor lighting conditions, and be careful not to include shadows or reflected light.
(4) For the photographed image, adjust the white balance in the photographing area, and set the value of H (hue) in the HSV color space of the material constituting the core wrap layer (the area that does not overlap with the indicator layer) to a range of 40 to 70. within
(5) Next, in the measurement target area, the area of the part where the value of H (color layer) is 100 or more is measured, and the value obtained by dividing by the area of the entire measurement target area is the absorbent article with respect to the area of the indicator layer. is the ratio of the area of the impregnated portion of the core wrap layer viewed from the stacking direction.

The value obtained by dividing the area of the color portion of the material constituting the indicator layer on the non-skin facing side of the core wrap layer by the area of the indicator layer is the core wrap layer impregnated portion of the absorbent article viewed from the lamination direction with respect to the area of the indicator layer. The ratio of the area of Similarly, the value obtained by dividing the area of the color portion of the material constituting the indicator layer on the skin facing side of the core wrap layer by the area of the indicator layer is It is defined as the ratio of the area of the part that reaches the surface.

The results are shown in Table 1 below.

REFERENCE SIGNS LIST 1 disposable diaper 2 top sheet layer 3 leakproof layer 31 low basis weight region 4 absorbent layer 4a absorbent core layer 4b core wrap layer 41 high density region 5 indicator layer 51 liquid component 52 core wrap impregnated portion 53 leakproof layer impregnated portion

Claims (16)

It has a top sheet layer, an absorbent layer, an indicator layer, and a leak-proof layer in this order,
The absorbent layer has an absorbent core layer and a core wrap layer covering at least the leakproof layer side of the absorbent core layer,
The indicator layer is
In the initial state before contact with urine, the appearance color is adjusted to the alkaline side, and when it comes into contact with urine, the color can be changed according to the specific gravity of urine, and at least partially, the core wrap layer and the leak-proof layer are formed. directly joined and positioned between them,
absorbent article. An absorbent article according to claim 1, wherein said indicator layer comprises a thermoplastic component having a melting point or softening point within the range of 40°C to 120°C. 3. The absorbent article according to claim 1, wherein the indicator layer further contains at least one of a hydrophilic polymer and an amine cationic surfactant. The absorbent article according to any one of claims 1 to 3, wherein the indicator layer changes color to blue or green when in contact with urine having a low specific gravity, and changes color to yellow or orange when in contact with urine having a high specific gravity. The indicator layer contains a liquid component that is liquid at 36° C.,
When the absorbent article is viewed from the stacking direction, the liquid component impregnates the leak-preventing layer in at least part of a portion of the leak-preventing layer that overlaps with the indicator layer.
The absorbent article according to any one of claims 1-4. The anti-leakage layer is a layer of hydrophobic non-woven fabric,
The indicator layer has a leak-proof layer-impregnated portion that is embedded in the leak-proof layer.
The absorbent article according to any one of claims 1-5. further comprising a backsheet layer on the opposite side of the leak-proof layer to the side on which the indicator layer is arranged;
Claims 1 to 1, wherein when the absorbent article is viewed from the stacking direction, at least a portion of the area of the backsheet layer that overlaps with the indicator layer has a basis weight smaller than that of other portions of the backsheet layer. 7. The absorbent article according to any one of 6. When the absorbent article is viewed from the stacking direction, the layers closer to the leak-proof layer than the indicator layer, in the region overlapping at least the indicator layer, have a total of 30.5 mm in the visible spectrum region. The absorbent article according to any one of claims 1 to 7, having a visible light transmittance of 0% or more and 90.0% or less. The absorbent article according to any one of Claims 1 to 8, wherein the indicator layer has a core wrap layer impregnated portion that extends into the core wrap layer. 10. The absorbent article according to claim 9, wherein the area of the core wrap layer-impregnated portion is 20.0% or more of the area of the indicator layer when the absorbent article is viewed from the stacking direction. The core wrap layer impregnated portion partially reaches the surface of the core wrap layer on the absorbent core layer side and is in contact with the absorbent core layer,
The absorbent article according to claim 9 or 10. When the absorbent article is viewed from the stacking direction, the area of the portion of the core wrap layer impregnated portion that reaches the absorbent core layer side is 50.0% or less of the area of the indicator layer.
12. The absorbent article according to claim 11. The absorbent core layer of any one of claims 1 to 12, wherein when the absorbent article is viewed from the lamination direction, at least a portion of the region overlapping the indicator layer of the absorbent core layer has a higher density than other regions of the absorbent core layer. An absorbent article according to any one of the preceding claims. The absorbent article according to any one of claims 1 to 13, wherein the indicator layer has a non-impregnated portion impregnated with neither the core wrap layer nor the leak-proof layer. The absorbent article according to any one of claims 1 to 14, which is for toilet training. In the initial state before contact with urine, the appearance color is adjusted to the alkaline side, and when it comes into contact with urine, it can change color according to the specific gravity of urine, and has a melting point or softening point within the range of 40°C to 120°C. containing a thermoplastic component,
indicator composition.

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