JP2012100945A - Absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorbent article that reduces heat and humidity during wear and has a smooth and dry skin contact surface of the top sheet even after absorption of excreta.SOLUTION: The absorbent article includes: the liquid-permeable top sheet; a liquid-impermeable back sheet; and an absorber between the liquid-permeable top sheet and the liquid-impermeable back sheet. The absorbent article has a heat retention of no greater than 45% and a rewetting rate of no greater than 10 mass%.

Description

  The present invention relates to an absorbent article having a heat retention rate of 45% or less and a rewetting rate of 10% by mass or less.

  Absorbent articles such as sanitary napkins, disposable diapers, etc. have improved their basic performance due to many years of technological development, and after having absorbed menstrual blood, urine and other excreta, Etc. have been reduced, and at present, further enhancement of functionality, for example, having a feeling of wearing close to underwear, for example, being hard to feel stuffiness when worn, and even after absorbing excrement, the top sheet is There is a demand for smoothness. In addition, the said stuffiness tends to occur when a wearer feels heat at the time of wearing and sweats.

For example, Patent Document 1 describes a surface sheet (top sheet) for absorbent articles, characterized in that the air permeability in the horizontal direction under a pressure of 10 cN / cm ² is 10 mL / cm ² · sec or more. As an effect, it is mentioned that it is hard to feel stuffiness when worn.
However, since the surface sheet described in Patent Document 1 is designed to ensure horizontal air permeability by providing irregularities that are not easily crushed even when a load is applied in the thickness direction, it is inevitable. The thickness becomes thicker.

JP 2003-126147 A

When the inventor of the present application confirmed, the absorbent article including the surface sheet described in Patent Document 1 has high heat retention due to its thickness, and the wearer feels heat when worn, leading to sweating. It has been found that the stuffiness when worn cannot be completely eliminated. In addition, in patent document 1, in order to make it hard to feel the stuffiness at the time of wear, it is not described at all about how to design components other than the surface sheet, for example, the absorber.
Therefore, an object of the present invention is to provide an absorbent article that is not easily stuffy when worn and that has a smooth skin contact surface of a top sheet even after absorbing excrement.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a liquid-permeable top sheet, a liquid-impermeable back sheet, the liquid-permeable top sheet, and a liquid-impermeable back sheet An absorbent article comprising an absorbent body between the absorbent article, wherein the absorbent article has a heat retention of 45% or less and a rewetting rate of 10% by mass or less, The present inventors have found that the above problems can be solved and have completed the present invention.

Specifically, the present invention relates to the following aspects.
[Aspect 1]
An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body between the liquid-permeable top sheet and the liquid-impermeable back sheet,
The absorbent article has a heat retention of 45% or less and a rewetting rate of 10% by mass or less;
An absorbent article as described above.

[Aspect 2]
The absorbent article according to aspect 1, wherein the moisture content of the skin contact surface of the liquid-permeable top sheet is 20% by mass or less.
[Aspect 3]
The thickness in the excretion opening | mouth contact area | region of the said absorbent article is 7 mm or less, and the density in the excretion opening | mouth contact area of the said absorbent article is 0.07 g / cm < ³ > or more, or aspect 1 or 2 Absorbent articles.

[Aspect 4]
Of the absorber, the basis weight at the excretory opening contact region is in the range of 250~500g / m ^2, the absorbent article according to any of aspects 1-3.
[Aspect 5]
The absorbent article according to any one of aspects 1 to 4, wherein the basis weight of the absorbent body in a region other than the excretion opening contact area is less than the basis weight of the excretion opening contact area.

[Aspect 6]
The absorbent article according to any one of aspects 1 to 5, wherein the absorbent body has a plurality of compressed parts formed by squeezing a part of the absorbent body in the thickness direction. .
[Aspect 7]
The liquid permeable top sheet has irregularities on the skin contact surface, which have a plurality of convex portions and a plurality of concave portions extending in the longitudinal direction of the absorbent article alternately in a direction perpendicular to the longitudinal direction. The absorbent article according to aspect 6, wherein the absorbent article is a non-woven fabric.

[Aspect 8]
The liquid-permeable top sheet is a non-woven fabric having irregularities and holes, having holes in which the non-woven fabric does not exist, in a part of the plurality of recesses,
The absorptivity according to aspect 7, wherein in the absorbent article, the hole of the liquid-permeable top sheet and the compressed portion of the absorbent body are at least partially overlapped in the thickness direction of the absorbent article. Goods.

[Aspect 9]
The absorbent article further includes a second sheet between the liquid-permeable top sheet and the absorber,
The said absorbent article has a plurality of pressing parts formed by pressing together the said liquid-permeable top sheet and second sheet in those lamination directions, The aspect 1 any one of aspects 1-8. Absorbent article.

[Aspect 10]
Any of Aspects 1-9, wherein the absorbent article has a plurality of pressing parts formed by pressing the liquid-permeable top sheet, the desired second sheet, and the absorbent body together in the laminating direction. The absorbent article as described in any one.

  The absorbent article of the present invention is less stuffy when worn, and the skin contact surface of the top sheet is smooth even after excrement is absorbed.

FIG. 1 is a view showing a moisture content measuring apparatus capable of measuring the moisture content of the skin contact surface of the top sheet. FIG. 2 is a diagram illustrating an example of the positional relationship between the sensor 2 and the sample 4 when the moisture content is measured using the moisture content measuring apparatus shown in FIG. FIG. 3 is a diagram showing one embodiment of an absorber used in the present invention. FIG. 4 is a diagram illustrating an example of a nonwoven fabric having unevenness. Drawing 5 is a figure for explaining the process of manufacturing the nonwoven fabric which has unevenness. FIG. 6 is a schematic diagram of one embodiment of a nonwoven fabric having irregularities and holes. Drawing 7 is a figure for explaining the state where the hole and the pressing part of an absorber have overlapped at least partially in the thickness direction of an absorptive article. FIG. 8 is a view showing one embodiment of the absorbent article of the present invention. FIG. 9 is a graph showing the relationship between the voltage and the moisture content obtained in Example 1. FIG. 10 is a diagram showing the relationship between the thickness in the excretory opening contact area and the heat retention rate obtained in Example 2. FIG. 11 is a diagram showing the relationship between the density in the excretory opening contact area and the heat retention rate obtained in Example 2. FIG. 12 is a diagram showing the relationship between the density in the excretory opening contact area and the rewet obtained in Example 2.

The absorbent article of the present invention will be described in detail below.
The absorbent article of the present invention is characterized by having a heat retention rate of about 45% or less and a rewetting rate of about 10% by mass or less, and the heat retention rate of the absorbent article is about 45% or less and the rewetting rate. It was found by the inventors of the present invention that the amount of the water content is about 10% by mass or less, and it is hard to be stuffy at the time of wearing and is smooth even after absorbing the excrement.

The said heat retention rate can be measured as follows.
(1) KES-F7 precision rapid thermophysical property measuring device manufactured by Kato Tech Co., Ltd. Thermolab II is prepared, and the room temperature is adjusted to 20 ° C. and the humidity is adjusted to 60% RH.
(2) When measuring the heat retention rate of the disposable diaper, centering on the center of the excretory opening contact area, the direction perpendicular to the longitudinal direction (hereinafter referred to as the direction perpendicular to the longitudinal direction) is simply “ Cut a 12 cm sample (sometimes referred to as “orthogonal direction”).
When measuring a sanitary napkin, it is generally difficult to secure a 12 cm × 12 cm sample. Therefore, an 8 cm sample in the longitudinal direction and an 8 cm sample in the orthogonal direction are centered on the center of the excretory opening contact area. Cut.

(3) The sample is attached to the sample frame attached to Thermolab II with double-sided tape. In the case of disposable diapers, the sample is attached to the sample frame according to the normal procedure of the above measuring device, and in the case of sanitary napkins, commercially available shorts cut into 12 cm × 12 cm, for example, cotton The manufactured shorts are affixed to the sample frame with double-sided tape, and then the sample is affixed to the shorts with double-sided tape so that the sample is in the center of the sample frame.
(4) In Thermolab II, the wind speed of the wind tunnel is set to 30 cm / second, and the temperature of BT-Box is set to 30 ° C.

(5) measuring the heat quantity Q _d required to hold the temperature of the pasted sample frame the sample to 30 ° C..
(6) Measure the amount of heat Q ₀ required to keep the temperature of the sample frame at 30 ° C. in the absence of a sample. In the case of disposable diapers, the amount of heat Q ₀ is measured with only the sample frame placed on the BT-Box. In the case of a sanitary napkin, the sample frame with shorts attached is placed on the BT-Box. The amount of heat Q ₀ is measured under the condition.
(7) The heat retention rate is calculated according to the following equation (1).
Thermal insulation rate (%) = 100 × (Q ₀ −Q _d ) / Q ₀ formula (1)

In the absorbent article of the present invention, the heat retention rate is about 45% or less, preferably about 43% or less, and more preferably about 42% or less. This is because the higher the heat retention rate, the more the wearer feels heat when wearing, sweating, and more likely to cause stuffiness. In addition, the minimum of the said heat retention is about 0%. By bringing the heat retention rate close to about 0%, the heat can be brought close to a state where no absorbent article is attached.
The heat retention rate can be lowered, for example, by reducing the thickness of the absorbent article, in particular, by reducing the thickness of the absorbent article in the excretory opening contact area. It is considered that by reducing the thickness of the absorbent article, the amount of air having high heat retention existing inside the absorbent article is reduced, and the heat retention rate of the absorbent article is lowered.

  Since the above heat retention rate also changes depending on the density of the absorbent article described later, it is difficult to discuss the heat retention only by the thickness of the absorbent article, but in order to achieve a heat retention rate of about 45% or less, absorption The thickness of the absorbent article, in particular, the thickness of the absorbent article in the excretory opening contact area can be, for example, about 7 mm or less, about 6 mm or less, about 5 mm or less. In addition, it is preferable that the thickness of the absorbent article, in particular, the thickness of the absorbent article in the excretory opening contact area is about 0.1 mm or more. This is because if the thickness of the absorbent article is less than 1 mm, the total amount of excreta absorbed tends to be insufficient.

  The thickness of the absorbent article is, for example, using TM600-L manufactured by Kumagai Riki Kogyo under the conditions of a probe tip diameter: 50 mm, a probe descending speed: 7.5 mm / second, and a measurement load: 50 gf. Can be measured.

  The heat retention rate can also be lowered by increasing the density of the absorbent article, in particular by increasing the density of the absorbent article in the excretory opening contact area. It is considered that by increasing the density of the absorbent article, the amount of air having high heat retention existing inside the absorbent article is reduced, and the heat retention rate of the absorbent article is lowered.

As described above, since the heat retention rate also changes depending on the thickness of the absorbent article, it is difficult to discuss the heat retention only by the density of the absorbent article, but in order to achieve a heat retention rate of about 45% or less. , the density of the absorbent article, in particular, the density of the absorbent article at the excretory opening contact region, for example, from about 0.04 g / cm ³ or more, about 0.05 g / cm ³ or more, about 0.06 g / cm ³ or more , About 0.07 g / cm ³ or more.
In addition, the density of the absorbent article of the present invention, particularly the density of the absorbent article in the excretory opening contact area is preferably about 0.5 g / cm ³ or less, and more preferably about 0.3 g / cm ^3. It is as follows. This is because as the density of the absorbent article increases, the rigidity of the absorbent article tends to increase.

  In the present specification, the “excretion opening contact area” generally means an area in contact with the wearer's excretion opening, and in a disposable diaper, it generally means an area in contact with the urination part, and a sanitary napkin In general, this means a region in contact with the vaginal opening. Moreover, in order to absorb excretion, when the area | region with much basic weight exists in an absorber, the said area with much basic weight can be handled as an excretion opening | mouth contact | abutting area for convenience.

Moreover, in this specification, when the absorbent article has a flap, the “center of the excretory opening contact area” means the center of the flap in the longitudinal direction of the absorbent article and the center of the absorbent article in the orthogonal direction. When the absorbent article does not have a flap, it means the center of the portion having the depression in the longitudinal direction of the absorbent body and the center in the orthogonal direction of the absorbent article.
Further, in the present specification, the density is measured by measuring the mass m (g) of an absorbent article by cutting a sample 2 cm in the longitudinal direction and 2 cm in the orthogonal direction centering on the center of the excretory opening contact area. To calculate. In addition, the value measured by TM600-L made from the above-mentioned Kumagai Riki industry can be used for thickness h (mm) of an absorbent article.
The density D (g / cm ³ ) is obtained by the following equation (2).
D = m / (2 × 2 × 0.1 × h) Formula (2)

The rewetting rate can be measured as follows.
(1) An acrylic plate having a hole of about 40 mm × about 10 mm in the center on the liquid-permeable top sheet of the absorbent article, and the center of the hole of the acrylic plate and the excretory opening contact area of the absorbent article Place it so that the center approximately overlaps.
(2) Put artificial menstrual blood into the autoburette, and drop 4 g of artificial menstrual blood from about 10 mm to about 15 mm in height toward the center of the hole in the acrylic plate. The rate at which artificial menstrual blood is dripped is about 95 mL / min.

(3) After confirming that the artificial menstrual blood has been absorbed by the absorbent article, remove the acrylic plate, and after 1 minute from the start of dripping of the artificial menstrual blood, the excretory opening contact area is centered on the top sheet. As described above, 10 sheets of filter paper (Advantech Toyo No. 2, size: 50 mm × 35 mm) whose mass (A) has been measured in advance are placed, and a weight is placed thereon so that a pressure of 30 g / cm ² is applied to the filter paper.
(4) One minute after placing the weight, after removing the weight and the filter paper from the absorbent article, the weight (B) of the filter paper is measured.

(5) The rewet rate is calculated according to the following equation (3).
Rewetting rate (mass%) = 100 × {mass (B) −mass (A)} / 4 Formula (3)
Artificial blood is not particularly limited as long as the viscosity is generally within the range of about 22 to about 26 mPa · s. For example, 80 g of glycerin, 8 g of sodium salt of CMC for 1000 cc of water, It can be prepared by mixing 10 g of NaCl, 4 g of NaHCO3, 8 g of red dye 102, 2 g of red dye 2, and 2 g of yellow dye 5.

  In the absorbent article of the present invention, the rewetting rate is about 10% by mass or less, preferably about 8% by mass or less, and more preferably about 7% by mass or less. This is because the higher the rewetting rate, the more likely that the absorbent article will feel sticky when pressure is applied to the absorbent article, for example, by sitting on a chair after absorbing the excrement. In addition, the minimum of the said rewet rate is about 0 mass%. By making the rewetting rate close to about 0% by mass, the absorbent article of the present invention can easily maintain a smooth state after absorbing excrement.

The rewetting rate can be lowered, for example, by increasing the density of the absorbent article, in particular, by increasing the density of the excretory opening contact area of the absorbent article. In particular, by increasing the density of the absorbent article in the excretory opening contact area, the distance between the fibers of the nonwoven fabric in the absorbent article and the pulp inside the absorbent body is reduced, so the excrement is absorbed by the capillary phenomenon. It is considered that the rewetting rate is lowered because the material is easily drawn into and held in the article.
In order to achieve a rewetting rate of 10% by weight or less, the density of the absorbent article in the excretory opening contact area is preferably about 0.07 g / cm ³ or more, more preferably about 0.08 g / cm ³ or more, and More preferably, it is about 0.09 g / cm ³ or more.

In addition, as described above, the density of the absorbent article in the excretory opening contact area is preferably about 0.5 g / cm ³ or less, and more preferably about 0.3 g / cm ³ or less. This is because as the density of the absorbent article increases, the rigidity of the absorbent article tends to increase.

In the absorbent article of the present invention, the moisture content of the skin contact surface of the top sheet is preferably about 20% by mass or less, more preferably about 18% by mass or less, and about 17% by mass or less. More preferably. By reducing the moisture content of the skin contact surface of the top sheet, the moisture content of the top surface of the skin contact surface of the top sheet is reduced, and the skin contact surface of the top sheet becomes smooth even after excretion is absorbed. Can keep the state. The moisture content is preferably about 0.3% by mass or more, and more preferably about 1.0% by mass or more. This is because if the moisture content is too low, static electricity is likely to occur during wearing depending on the climate.
The moisture content of the skin contact surface of the top sheet can be measured as follows.

(1) A moisture content measuring apparatus as shown in FIG. 1 is prepared, and the room temperature is adjusted to 20 ° C. and the humidity is adjusted to 60% RH. The details of the moisture content measuring apparatus will be described later.
(2) Prepare a plurality of samples with known moisture percentages, measure the voltage (V) applied between the pair of electrodes in these samples, and create a calibration curve.
(3) Put artificial menstrual blood into the autoburette, and drop 4 g of artificial menstrual blood toward the center of the excretory opening contact area of the liquid-permeable top sheet.
(1) After 1 minute has elapsed, centering on the center of the excretory opening contact area, in the 12 mm longitudinal direction of the absorbent article and 30 mm in the orthogonal direction, the voltage at 15 locations is measured at random, from the average value Based on the calibration curve, the moisture content is converted.

  A moisture amount measuring apparatus 1 shown in FIG. 1 is a sample stage on which a sensor 2 that is a capacitance-type moisture sensor and a sample to be measured are placed, and the sample is placed thereon. Controlling the sample stage 3 having a convex surface, a support mechanism 5 for supporting the sensor so that the contact pressure of the sensor with respect to the sample is substantially constant, a moving mechanism 6 for moving the sample, and the moving mechanism Thus, while the sensor is moved relative to the sample, the sensor includes a measurement mechanism 9 that measures the moisture content of the sample at a plurality of locations and thereby measures the moisture content distribution of the sample.

  In the moisture content measuring apparatus 1 shown in FIG. 1, the sample stage 3 has a semi-circular cylinder shape formed by cutting a regular cylinder along a plane passing through the central axis. Further, in the moisture content measuring apparatus 1 shown in FIG. 1, the support mechanism 5 is a balance that can adjust the load applied to the sample 4 by the position of the weight 8, and the vertical direction ( Hereinafter, a certain load may be applied to the “direction B”.

  In the moisture content measuring apparatus 1 shown in FIG. 1, the moving mechanism 6 rotates the sample stage 3 along the direction A around the central axis of the regular cylinder, and the sample stage 3 is aligned with the central axis of the regular cylinder. In parallel, that is, in FIG. 1, it can be reciprocated from the front to the back. The moving mechanism 6 rotates the sample table 3 in the direction A, and further reciprocates the sample table 3 from the front to the back, thereby evaluating the moisture content distribution of the sample.

In the moisture content measuring apparatus 1 shown in FIG. 1, the sensor 2 is connected to the measuring mechanism 9 via the support mechanism 5 and the moving mechanism 6 is directly connected to the measuring mechanism 9.
In the moisture content measuring apparatus 1 of FIG. 1, a sample 4 is set on a sample table 3, and an insulating film 7 is disposed between the sensor 2 and the sample 4 and covers the sample 4.

  In the moisture content measuring apparatus 1 shown in FIG. 1, the procedure for measuring the moisture content distribution of the sample 4 is as follows. First, the moisture content measuring apparatus 1 shown in FIG. 1 is prepared. Next, the sample 4 is placed on the convex surface of the sample stage 3, the insulating film 7 is placed on the sample 4, and the sensor 2 is placed on the sample 4 with the insulating film 7 interposed therebetween. Next, the measuring mechanism 9 is operated to control the moving mechanism 6 to rotate the sample stage 3 in the A direction around the center axis of the regular cylinder of the sample stage 3 and to move the sample stage 3 from the near side to the far side. Move. Accordingly, the sensor 2 is caused to measure the moisture content of the sample 4 at a plurality of locations. By combining them, the moisture content distribution of the sample 4 can be measured.

A commercially available capacitive moisture sensor can be arbitrarily employed as the sensor, but the capacitive moisture sensor can have a cross-sectional shape as shown in FIG.
The sensor 2 shown in FIG. 2 has a pair of electrodes 10a and 10b arranged in parallel at a predetermined interval. The capacitance between the pair of electrodes 10a and 10b is measured via a metal wire. The sensor 2 shown in FIG. 2 also includes an electrode support portion 11 for supporting the pair of electrodes 10a and 10b. In the sensor 2 shown in FIG. 2, a pair of electrodes 10 a and 10 b are attached to the measurement-side surface of the electrode support 11.

  The electrode support part preferably has a non-dielectric constant, a water content, and a water permeability equivalent to those of an insulating film described later so as not to affect the moisture content measurement. As an example of the material of the electrode support part, for example, a phenol resin known by a trade name such as bakelite can be cited.

  In the sensor 2 shown in FIG. 2, nothing exists between the pair of electrodes 10a and 10b. However, in another embodiment of the moisture content measuring apparatus, between the pair of electrodes 10a and 10b, The electrode support part may be further arranged. By disposing the electrode support portion between the pair of electrodes 10a and 10b, the distance between the electrode and the sample can be kept more constant.

  The sensor 2 shown in FIG. 2 is in contact with the sample 4 with an insulating film 7 interposed therebetween. Since a constant vertical load is applied to the sensor 2, the sensor 2 can measure the capacitance while keeping the distance between the pair of electrodes 10a and 10b and the sample 4 constant. .

The reason why the moisture measuring device includes an insulating film disposed between the sensor and the sample and covering the sample is as follows.
An absorbent article that is a sample to be measured, for example, an absorbent surface of a disposable diaper, may reach a moisture content close to 100% after urination. In such a high moisture content situation, when trying to measure the moisture content using a moisture sensor, a part of the moisture remains attached to the sensor, particularly near the electrodes, and the measurement results are likely to contain errors. . Therefore, it is possible to prevent moisture from adhering to the sensor by disposing an insulating film separate from the sensor between the sensor and the sample.

  In the moisture content measuring apparatus, as shown in FIG. 2, the sensor itself does not need to have an insulating portion for maintaining the properties of the electrode as a capacitor on the surface in contact with the sample. Further, like a known or commercially available capacitance type moisture sensor, the sensor may have an insulating portion for retaining the properties of the electrode as a capacitor on the surface in contact with the sample.

  Due to the nature of measuring the moisture content of the insulating film, the ratio to the dielectric constant of the vacuum (hereinafter simply referred to as “relative dielectric constant”) is preferably about 30 or less, and about 20 or less. Is more preferably about 10 or less, and most preferably about 5 or less. This is because a high non-dielectric constant can cause measurement errors.

The insulating film is preferably thin and uniform in order to reduce measurement errors.
The film thickness is preferably about 300 μm or less, more preferably about 200 μm or less, further preferably about 100 μm or less, further preferably about 50 μm or less, and about 30 μm or less. Most preferably it is.
As the uniformity, the coefficient of variation of the film thickness measured arbitrarily at 30 points is preferably about 20% or less, more preferably about 10% or less, and further about 5% or less. preferable.
The coefficient of variation is expressed by the following equation (4):
Coefficient of variation (%) = 100 × standard deviation / arithmetic mean equation (4)
Is a value calculated by.

In addition, the insulating film preferably has a low moisture content in order to reduce measurement errors. This is because if the moisture content is high, the non-dielectric constant of the insulating film increases and the measurement error may increase.
As a measure of the moisture content, the moisture content after being immersed in water at 25 ° C. for 24 hours is preferably less than about 3% by mass, more preferably less than about 1% by mass, and about 0 More preferably, it is less than 5 mass%.
Furthermore, the insulating film preferably has low water permeability. As a measure of the low water permeability, it is sufficient if the sensor, particularly the electrode, does not get wet with water during the measurement. This is because the capacitance cannot be measured when the electrode gets wet with water.

The material for the insulating film is not particularly limited as long as it satisfies the above performance, and examples thereof include polyamide, melamine, epoxy, polyethylene, polypropylene, polyvinylidene chloride, polyvinyl chloride, and polymethylpentene.
By including the insulating film, the moisture content measuring device is preferably about 0% by mass to about 100% by mass, more preferably about 1% by mass to about 90% by mass, and further preferably about 5% by mass to about 80% by mass. Samples with a very wide range of moisture percentages by mass% can be measured.

  In addition, although the moisture content of the skin contact surface of the top sheet can be measured easily and with good reproducibility by using the above moisture content measuring apparatus, a commercially available capacitance type moisture sensor can be used. It would also be possible to measure the moisture content of the skin contact surface of the top sheet.

In order to achieve the effect of the present invention, the thickness of the absorbent article in the excretory opening contact area is about 7 mm or less, and the density of the absorbent article in the excretion opening contact area is about 0.07 g / cm ³ or more. Preferably, the thickness of the absorbent article in the excretory opening contact area is about 6 mm or less, and the density of the absorbent article in the excretion opening contact area is more preferably about 0.07 g / cm ³ or more. More preferably, the thickness of the absorbent article in the excretory opening contact area is about 5 mm or less and the density of the absorbent article in the excretion opening contact area is about 0.07 g / cm ³ or more. Most preferably, the thickness of the absorbent article in the contact area is about 5 mm or less and the density of the absorbent article in the excretion opening contact area is about 0.075 g / cm ³ or more.

As described above, the thickness of the absorbent article in the excretory opening contact area is preferably about 0.1 mm or more. This is because if the thickness is less than 1 mm, the total amount of excreta absorbed tends to be insufficient. Also, the density of the absorbent article in the excretory opening contact area is preferably about 0.5 g / cm ³ or less, and more preferably about 0.3 g / cm ³ or less. This is because as the density increases, the rigidity of the absorbent article tends to increase.

The basis weight of the absorbent body used in the absorbent article of the present invention in the excretory opening contact area is such that the absorbent article of the present invention has a heat retention rate of about 45% or less and a rewetting rate of about 10% by mass or less. Although it will not be restrict | limited especially if it is the range which has, For example, about 250-about 500 g / m < ² >, about 250-about 400 g / m < ² >, about 250-about 350 g / m < ² > etc. can be mentioned. When the basis weight of the absorber in the excretory opening contact area decreases, the rewet rate tends to increase, and when the basis weight of the absorbent in the excretion opening contact area increases, the wearing feeling tends to be hard.

The basis weight in the region other than the excretion opening contact area of the absorbent body used in the absorbent article of the present invention is preferably smaller than the basis weight in the excretion opening contact area, for example, about 300 g / m ² or less, It can be about 200 g / m ² or less, about 100 g / m ² or less. When the basis weight of the absorbent in areas other than the excretory opening contact area increases, the rewetting rate tends to decrease, but the heat retention rate tends to increase due to its thickness, and the thickness is reduced by pressing. In some cases, the feeling of wearing tends to be hard.

  In the absorbent body used in the absorbent article of the present invention, it is preferable that a plurality of squeezed portions formed by squeezing a part of the absorbent body in the thickness direction are present on the entire surface of the absorbent body. By compressing the entire surface of the absorbent body, the density of the absorbent body, and consequently the density of the absorbent article of the present invention, can be increased, and the heat retention rate and rewetting ratio of the absorbent article of the present invention can be lowered.

  FIG. 3 is a diagram showing one embodiment of an absorber used in the present invention. In the absorbent body 21 shown in FIG. 3, the left side is the direction that becomes the front of the wearer when worn, and the right side is the direction that becomes the rear of the wearer when worn. In the absorbent body 21 of FIG. 3, a plurality of compressed parts 23 are present on the entire surface, and in the absorbent body 21, the excretory opening contact area 22 is indicated by a dotted line.

The shape, area, number, etc. of the compressed parts are not particularly limited, but as shown in FIG. 3, it is preferable that the compressed parts having a small area are arranged almost uniformly. It is because the whole absorptive article can be made thin, reducing the area ratio of the pressing part with little excretion absorption ability by making the pressing part scattered almost uniformly.
Moreover, in the absorbent body used in the present invention, the plurality of compressed parts can be arranged so that the absorbent article is easily deformed to some extent along the shape of the wearer's body. For example, over the entire surface of the absorbent body, by arranging a substantially rectangular squeezed portion with a certain interval in the orthogonal direction of the absorbent body so that the longitudinal direction of the compressed part coincides with the orthogonal direction of the absorbent body, The absorbent article can be easily deformed along the shape of the wearer's buttocks.

Furthermore, as FIG. 3 shows, in the area | region which contacts a wearer's groin part among absorbers, as for the compression part 23, the longitudinal direction of the compression part 23 corresponds with the longitudinal direction of the absorber 21, By arranging the absorbent body at a certain interval in the longitudinal direction, the absorbent article can be easily followed when the wearer closes the leg.
Furthermore, as shown in FIG. 3, in the excretion opening contact area 22 of the absorbent body 21, the excretion opening contact area 22 can be easily expanded by reducing the number of pressing parts 23, and a larger amount of excrement can be obtained. Can be easily absorbed. In addition, in order to make it easier to absorb a large amount of excrement, the area of the pressing part per one in the excretion opening contact area may be reduced.

  In the substantially rectangular compressed portion in the absorbent body, the major axis is preferably about 1.0 to about 3.0 mm, more preferably about 1.5 to about 2.5 mm, and the minor axis is About 0.2 to about 2 mm, and more preferably about 0.3 to about 1.0 mm. When the shape of the compressed portion is reduced, the compression tends to be insufficient, and when the shape is increased, the rigidity of the absorbent article of the present invention is increased, and the wearing feeling tends to be impaired.

In the absorbent body, the area ratio of the compressed portion to the compressed surface of the absorbent body is preferably about 1 to about 10%, and more preferably about 2 to about 5%. When the area ratio is small, pressing becomes insufficient.As a result, the thickness of the absorbent body and the absorbent article is increased, the density of the absorbent article tends to be low, and when the area ratio is high, Absorbent articles tend to be more rigid and less absorbent.
In addition, the said area ratio can be calculated by multiplying the number of the pressing parts of an absorber by the area per pressing part, and dividing by the area of the pressing surface of an absorber.

Moreover, it is preferable that the said pressing part is arrange | positioned in a staggered type, for example, a square staggered type, a 60 degree zigzag type, etc. in an absorber. This is because the distribution is unlikely to occur in the thickness, density, etc. of the absorber.
As for the said pressing part, it is preferable that adjacent pressing parts are in the space | interval of about 1 mm-about 10 mm, and it is more preferable that it exists in the space | interval of about 2-about 6 mm. This is because the distribution is unlikely to occur in the thickness, density, etc. of the absorber.

  The structure of the absorbent body is not particularly limited, and for example, an absorbent core formed from absorbent fibers, such as pulp, and an optional absorbent material, such as SAP, is covered with a liquid-permeable tissue or the like. Can be formed.

The liquid-permeable top sheet used for the absorbent article of the present invention is not particularly limited as long as the absorbent article of the present invention has a heat retention rate of 45% or less and a rewetting rate of 10% by mass or less. For example, a general through-air nonwoven fabric is mentioned.
Moreover, in order to produce the effect of the present invention, the liquid-permeable top sheet has a plurality of convex portions and a plurality of concave portions extending in the longitudinal direction of the absorbent article alternately in the orthogonal direction of the absorbent article. It is preferably a non-woven fabric having unevenness (hereinafter simply referred to as “non-woven fabric having unevenness”).

  FIG. 4 is a diagram illustrating an example of a nonwoven fabric having unevenness. 4 absorbs a plurality of convex portions 25 and a plurality of concave portions 26 (only one is shown in FIG. 4) extending in the longitudinal direction of the absorbent article. Alternately in the orthogonal direction of the article.

  The nonwoven fabric having the unevenness can be produced according to a conventionally known method, for example, a method described in JP-A-2008-25081, JP-A-2008-25082, or the like. Specifically, for example, as shown in FIG. 5, the fiber web 30 is placed on a roll having a support member 29 such as a mesh, and the fluid ejected from the fluid nozzle 31 is applied to the fiber web 30. Thus, the nonwoven fabric 24 having irregularities can be formed. In the nonwoven fabric 24 having irregularities, in the region immediately below the nozzle from which the fluid is ejected, the fibers are sorted in the orthogonal direction CD orthogonal to the conveyance direction MD, and a recess along the conveyance direction MD is formed. And in the area | region between each nozzle, a fiber gathers and the convex part along the conveyance direction MD is formed.

Examples of the fluid include steam. For example, an ejection amount of about 5 to about 15 (nL / m ² ) can be used. Further, since the concave portion of the nonwoven fabric is formed immediately below the fluid nozzle for spraying the fluid, and further, the convex portion is formed adjacent to the concave portion, the fluid nozzle interval is the height of the desired convex portion, the pitch of the concave and convex portions, etc. Can be defined.

The fiber in the nonwoven fabric which has the unevenness | corrugation formed from the said fiber web and the said fiber web is not restrict | limited in particular, For example, a polyethylene fiber, a polyethylene terephthalate fiber, and these combination are mentioned.
The basis weight of the fibrous web, and the average basis weight of the nonwoven fabric having irregularities formed from the fibrous web is preferably from about 10 to about 50 g / m ² and from about 20 to about 50 g / m ² . It is more preferable. When the basis weight decreases, the top sheet may be broken during use. When the said basic weight increases, the thickness of a top sheet will become thick and there exists a tendency for the heat retention of an absorbent article to rise.

In the nonwoven fabric having irregularities, the height of the convex portion is preferably about 0.5 to about 2.0 mm, and more preferably about 0.7 to about 1.5 mm. The height of the recess is preferably about 0.3 to about 0.7 mm, and more preferably about 0.5 to about 0.6 mm.
In the nonwoven fabric having irregularities, the pitch of the irregularities is preferably about 2 to about 6 mm, and preferably about 3 to about 5 mm.
In the present specification, the height of the projections, as indicated by h ₁ in FIG. 4, means a height from the bottom portion of the nonwoven fabric to the top of the convex portion, and the height of the recess 4 in as indicated by h _2, it means the height to the bottom of the recess from the bottom of the nonwoven fabric. Further, the pitch of the unevenness means a distance from a certain convex portion to an adjacent convex portion, as indicated by p in FIG.

  In the absorbent article of the present invention, the liquid-permeable top sheet has a plurality of convex portions and a plurality of concave portions extending in the longitudinal direction of the absorbent article on the skin contact surface in a direction perpendicular to the longitudinal direction. It is a non-woven fabric having irregularities and holes, which are alternately present and have holes in which the non-woven fabric does not exist in some of the plurality of recesses (hereinafter sometimes referred to as “non-woven fabric having irregularities and holes”). Is more preferable. When the liquid-permeable top sheet has holes, excretion is easily drawn into the absorber from the top sheet.

FIG. 6 is a schematic diagram of one embodiment of a nonwoven fabric having irregularities and holes. The nonwoven fabric 32 having unevenness and holes shown in FIG. 6 has a hole 33 in the recess 26 where no nonwoven fabric is present.
The hole preferably has a longitudinal diameter of the absorbent article of about 2.0 to about 2.5 mm, and the absorbent article has an orthogonal diameter of about 0.5 to about 1.5 mm. Preferably, the spacing between adjacent holes in the same recess is preferably about 2.0 to about 2.5 mm.
In addition, the height of the said convex part, the height of a recessed part, the pitch of an unevenness | corrugation, and the diameter of a hole can be measured from an electron micrograph.

  For example, in the manufacturing process of the nonwoven fabric having unevenness shown in FIG. 5, the holes are formed by projecting the support member 29 from the mesh or the like in the orthogonal direction perpendicular to the transport direction, and in the transport direction. It can manufacture simply by changing to the support body which has alternately. The hole may be formed at a portion where the fluid ejected from the fluid nozzle 31 intersects with the protruding portion of the support.

In the absorbent article of the present invention, when the absorbent body has a pressing part and the liquid-permeable top sheet is a nonwoven fabric having irregularities and holes, as shown in FIG. Are preferably overlapped at least partially in the thickness direction of the absorbent article.
Drawing 7 is a figure for explaining the state where the hole and the pressing part of an absorber have overlapped at least partially in the thickness direction of an absorptive article. FIG. 7 is a view of the absorbent article of the present invention as seen from the skin contact surface side of the liquid-permeable top sheet, and a part of the absorbent article is extracted. In FIG. 7, the pressing part 23 which an absorber has is shown with the dotted line for description. In FIG. 7, a region where the hole and the compressed portion overlap is indicated by reference numeral 34.
Since the absorbent article of the present invention has a plurality of regions 34 where the holes and the compressed parts overlap, the absorbed excrement passes through the regions 34 where the holes and the compressed parts overlap, and is quickly absorbed by the absorbent body. Can be done.

The absorbent article of the present invention can include a second sheet, if desired, between the liquid-permeable top sheet and the absorbent body.
Examples of the second sheet include nonwoven fabrics such as through-air nonwoven fabrics and biodegradable resins such as polylactic acid nonwoven fabrics.
Examples of the back sheet include those manufactured from polyester, polyacrylonitrile, polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyvinyl alcohol, or the like. Examples of the back sheet include a breathable film made of high-density polyethylene / low-density polyethylene, a non-breathable film, and an apertured film.

  In addition, when the absorbent article of the present invention includes a second sheet, the absorbent article of the present invention includes a plurality of squeezes formed by squeezing together a liquid-permeable top sheet and a second sheet in the laminating direction. It is preferable to have a part. By squeezing both the top sheet and the second sheet, excrement can be easily drawn into the absorbent body from the top sheet. Since the fiber density is high and the fibers tend to rise in the thickness direction of the absorbent article at the periphery of the compressed portion, excrement is easily drawn into the absorbent body from the top sheet.

  The absorbent article of the present invention can also have a plurality of pressing portions formed by pressing together a liquid-permeable top sheet, an optional second sheet, and an absorbent body in the stacking direction. By squeezing together the liquid-permeable top sheet, the desired second sheet, and the absorber, excreta can be easily drawn into the absorber from the top sheet. This is because the fiber density tends to rise in the thickness direction of the absorbent article at the periphery of the compressed portion.

  FIG. 8 is a view showing one embodiment of the absorbent article of the present invention. The absorbent article 35 shown in FIG. 8 includes a liquid-permeable top sheet 36, a second sheet (not shown), an absorbent body 21, a back sheet (not shown), and a side flap 37. The absorbent article 35 shown in FIG. 8 includes a pressing part 38 formed by pressing the top sheet and the second sheet, and a pressing part 39 formed by pressing the top sheet, the second sheet, and the absorbent body. Have.

Then, the manufacturing method of the absorbent article of this invention is demonstrated.
The absorbent article of the present invention can be produced by a method usually used in the art without any particular limitation.
As an example, the absorbent body used in the present invention is made of an absorbent fiber (for example, SAP) with a desired basis weight, and a desired absorbent (for example, SAP) is sprayed on the absorbent body with a liquid-permeable tissue. It can be formed by covering. You may squeeze an absorber in order to adjust the density of the absorbent article formed, thickness, etc. For example, as described in JP 2009-273722 A, any means known in the art can be used for the pressing.

Next, a liquid-permeable top sheet, an optional second sheet, and an absorber are laminated using an adhesive or the like. If desired, after the liquid-permeable top sheet and the second sheet are squeezed together, an absorber can be laminated thereon.
Then, if desired, the top sheet, the optional second sheet, and the absorber can be squeezed.
Next, after a back sheet is laminated on the absorbent body using an adhesive or the like, it is cut into a desired shape to produce the absorbent article of the present invention.

  Examples of the absorbent article of the present invention include items that absorb a certain amount of excreta, such as sanitary napkins and disposable diapers.

Hereinafter, although an example is given and the present invention is explained, the present invention is not limited to these examples.
[Example 1]
A standard sample of indices 1 to 6 having a different moisture content was prepared by including a certain amount of moisture in Silcot (trademark) (manufactured by Unicharm Corporation). Next, the standard sample was left in a sealed state at 20 ° C. for 1 day.

The water content measuring apparatus shown in FIG. 1 was prepared, the standard samples of indices 1 to 6 were placed on the sample stage of the water content measuring apparatus, and their water content was measured. The contact pressure of the sensor with respect to the sample was 8 g / cm ² .
The results are shown in Table 1 and FIG.

From the above data, a calibration curve passing through the origin was created by the method of least squares. Between the moisture content y and the voltage x, the following equation (5)
y = 32.7x + Formula (5)
was gotten.

[Example 2]
An absorbent article having a shape as shown in FIG. 8 was produced from the top sheet shown in Table 2, the optional second sheet and absorber, and the back sheet.

In Table 2, the nonwoven fabric 1 as the top sheet is a fiber web made of core-sheath fibers (fiber diameter: 3 dtx, fiber length: 45 mm) whose core / sheath is polyethylene terephthalate / high-density polyethylene. Non-woven fabric having irregularities and holes formed by processing according to the method described in the book (basis weight: 35 g / m ² , convex height: 1.1 mm, concave height: 0.5 mm, irregular Pitch: 1.0 mm, hole diameter: 2.5 mm (longitudinal direction of absorbent article) × 1 mm (perpendicular direction of absorbent article), spacing between adjacent holes: 2.5 mm).

The nonwoven fabric 2 is a through-air nonwoven fabric (basis weight: 35 g / weight) formed by through-air processing a fiber web composed of core-sheath fibers (fiber diameter: 3 dtx, fiber length: 45 mm) whose core / sheath is polyethylene terephthalate / high-density polyethylene. m ² , thickness: 1.1 mm).
The perforated film was obtained by perforating a polyethylene film containing 3% by mass of titanium oxide (basis weight: 23 g / m ² ) using a process as shown in US Pat. No. 5,733,628 (thickness: 1.1 mm). Pore diameter: 0.80 mm (MD) × 0.57 mm (CD), open area ratio: 23%.

In Table 2, the second sheet is a through-air nonwoven fabric (basis weight: 20 g / weight) formed by through-air processing a fiber web composed of polyethylene terephthalate / high-density polyethylene core-sheath fibers (fiber diameter: 3 dtx, fiber length: 45 mm). m ² , thickness: 0.19 mm).
In Table 2, the absorbent is placed on a liquid-permeable tissue with the basis weight pulp shown in Table 2, sprayed with a small amount of SAP, covered with the tissue, and then pressed (No. 6). Other than the above).
In Table 2, the back sheet is a polyethylene film (basis weight: 24 g / m ² ).

Laminate the top sheet and the second sheet using an adhesive, squeeze the top sheet and the second sheet, then laminate the absorbent body to the second sheet using an adhesive, and squeeze the top sheet, the second sheet, and the absorbent body Then, an absorbent article was manufactured by laminating a back sheet on the absorbent body using an adhesive and cutting it into the shape of the absorbent article.
The absorbent article No. In 8, after squeezing the top sheet, the absorbent body is laminated on the top sheet using an adhesive, the top sheet and the absorbent body are squeezed, and then the back sheet is laminated on the absorbent body using an adhesive. Absorbent articles were produced by cutting into the shape of the article.
Absorbent article no. Table 2 shows the configurations of 1 to 10, the thickness, and the density.

  Absorbent article no. 1-10, Unicharm Co., Ltd., Sophie Body Fit with wings (21 cm) (hereinafter referred to as “BFR”), Unicharm Co., Ltd. Sophie Body Fit Fuwapita Slim, for everyday use with wings 21 cm (hereinafter, "Fuwapita") and Unicharm Co., Ltd. Sophie has a heat retention rate, rewetting rate, and moisture content for many days to normal daily wings (hereinafter referred to as "Hadaomoi"). Table 3 shows the thickness and density of the absorbent article in the mouth contact area. In addition, the heat retention rate, the rewet rate, and the moisture content were measured according to the method described in this specification.

  Also, the absorbent article No. FIG. 10 shows the relationship between the thickness of the absorbent article and the heat retention rate in the excretory opening contact area in a commercially available absorbent article consisting of 1 to 10 and BFR, Fuwapita and Hadamoi, and the excretion opening contact area FIG. 11 shows the relationship between the density of the absorbent article and the heat retention rate. Absorbent article no. 1 to 10 show the relationship between the density of the absorbent article and the rewet rate in the excretory opening contact area.

  10 and 11, it can be seen that the heat retention rate decreases as the thickness of the absorbent article in the excretory opening contact area decreases and as the density of the absorbent article in the excretion opening contact area increases. In addition, it can be seen from FIG. 12 that the rewetting rate decreases as the density of the absorbent article in the excretory opening contact area increases.

  Absorbent article no. 1-No. 10 and BFR, Fuwapita and Hadaomoimo were used by multiple subjects. As the heat retention rate and rewet rate decreased, it became harder to stuffy and was still smooth after absorbing excrement. Got an answer. And absorbent articles No. 1, 3, 7, 8, and 10 having a heat retention of 45% or less and a rewetting rate of 10% by mass or less, and In No. 2, it was remarkably difficult to stuffy and the smooth feeling was remarkable.

DESCRIPTION OF SYMBOLS 1 Moisture content measuring apparatus 2 Sensor 3 Sample stand 4 Sample 5 Support mechanism 6 Movement mechanism 7 Insulating film 8 Weight 9 Measurement mechanism 10a, 10b Electrode 11 Electrode support part 21 Absorber 22 Excretion port contact area 23 Squeeze part 24 It has unevenness Nonwoven fabric 25 Convex portion 26 Concave portion 27 Central portion 28 Side portion 29 Support member 30 Fiber web 31 Fluid nozzle 32 Nonwoven fabric having irregularities and holes 33 Hole 34 Region where hole and pressing portion overlap 35 Absorbent article 36 Top sheet 37 Side flap 38 Squeezed part formed by squeezing top sheet and second sheet 39 Squeezed part formed by squeezing top sheet, second sheet and absorber

Claims (10)

An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body between the liquid-permeable top sheet and the liquid-impermeable back sheet,
The absorbent article has a heat retention rate of 45% or less and a rewetting rate of 10% by mass or less;
The said absorbent article characterized by these.   The absorptive article according to claim 1 whose moisture content of the skin contact side of said liquid permeability top sheet is 20 mass% or less. The thickness of the absorbent article in the excretion opening contact area is 7 mm or less, and the density of the absorbent article in the excretion opening contact area is 0.07 g / cm ³ or more. The absorbent article as described. Wherein the absorber, the basis weight at the excretory opening contact region is in the range of 250~500g / m ^2, the absorbent article according to any one of claims 1 to 3.   The absorptive article according to any one of claims 1 to 4 whose basic weight in fields other than an excretion mouth contact area of said absorber is smaller than the basic weight in said excretion mouth contact area.   The absorptivity as described in any one of Claims 1-5 in which the said absorber has the some pressing part formed by pressing a part of absorber in the thickness direction on the whole surface of an absorber. Goods.   The liquid-permeable top sheet has a plurality of protrusions and a plurality of recesses extending in the longitudinal direction of the absorbent article on the skin contact surface, and having irregularities alternately in a direction perpendicular to the longitudinal direction. The absorptive article according to claim 6 which is a nonwoven fabric which has. The liquid-permeable top sheet is a non-woven fabric having irregularities and holes, having holes in which the non-woven fabric does not exist, in a part of the plurality of recesses,
The said absorbent article WHEREIN: The absorption of Claim 7 in which the hole of the said liquid-permeable top sheet and the pressing part of the said absorber have overlapped at least partially in the thickness direction of the said absorbent article. Sex goods. The absorbent article further includes a second sheet between the liquid-permeable top sheet and the absorber,
The said absorbent article has a some pressing part formed by pressing together the said liquid-permeable top sheet and a 2nd sheet | seat in those lamination directions, It is any one of Claims 1-8. Absorbent articles.   The absorbent article according to claim 1, wherein the absorbent article has a plurality of pressing portions formed by pressing the liquid-permeable top sheet, an optional second sheet, and an absorbent body together in the stacking direction thereof. The absorbent article as described in any one.

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