JP2009178411A - Disposable diaper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disposable diaper having a skin contact surface with dry touch. <P>SOLUTION: Artificial urine of 40g is collectively poured into a central area of the skin contact surface of the disposable diaper, after a lapse of 20 seconds from starting the pouring, the BT-Box (Bottom Temperature Box) is mounted on an artificial urine injection part in the skin contact surface of the diaper, the amount of heat transfer from the BT-Box to the diaper under a load of 1.0 kPa is measured with time, and the maximum value of the measured amount of heat transfer is 3 W or less. The artificial urine of 80g is collectively poured into the central area, and after 10 minutes from starting the pouring, the maximum value of the amount of heat transfer measured under a load of 3.5 kPa is preferably 2 W or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a disposable diaper.

  A method for evaluating the cold / warm feeling of cloth by measuring heat absorption of the cloth has been established in the technical field of fibers and clothing (see Non-Patent Document 1). In this method, one side of a copper plate having a certain amount of heat is brought into contact with the fabric, the heat transfer from the copper plate to the fabric occurring within a short time immediately after that is measured, and the peak value q-max of the heat flow at that time is determined. Ask. It is evaluated that the measured object feels colder as the measured value of q-max is larger.

As an application of the above-described evaluation method, there is known a method for selecting and evaluating a top sheet of an absorbent article having a good smooth feeling (see Patent Document 1). In this method, a T-Box (Temperature Detection Box) provided in a THERMO LABO II (KES-F7), which is a precise rapid thermophysical property measuring apparatus manufactured by Kato Tech, is used. T-Box is a sensor dedicated to q-max measurement. In patent document 1, this T-Box is used, and the contact cold / warm feeling at the time of measuring the maximum heat transfer amount (q-max value) is 1.1 kw / m ² or less on the side contacting the skin of the wearer of the top sheet. And the q-max value on the side in contact with the absorber is larger than the q-max value on the side in contact with the wearer's skin, and the difference is 0.5 kw / m ² or more. A top sheet of an absorbent article having a good feeling is selected and evaluated.

  Moreover, in nonpatent literature 2, it is reported that q-max of a disposable diaper is measured in the state which absorbed the dry state and the physiological saline, and q-max increases by water absorption. And it has been concluded that an increase in q-max increases the cold feel when the diaper touches the skin.

K. Kawabata, Journal of the Textile Machinery Society, Vol. 37, no. 8 (1984), T130-T141 Hiroko Sasakura and Masako Niwa, Journal of Textile Machinery Society, Vol. 57, no. 9 (2004), T89-T94 JP 2004-57254 A

  However, when the present inventors examined in detail, it turned out that the information of the cool feeling obtained from the measurement of q-max reflects only the state of the very shallow area | region from the surface of a measuring object. Therefore, for example, in the absorbent article in which a certain amount of time has elapsed from the liquid absorption and the topsheet is dry, but the absorbent body is wet, the above-mentioned experience is not affected by the above-mentioned feeling. In the evaluation based on the measurement of q-max, it is determined that there is a feeling of lightness, and the evaluation result may deviate from the experience. Therefore, the conventional absorbent article developed using q-max as an index of the light feeling cannot be said to be sufficiently satisfactory.

  An object of the present invention is to provide a disposable diaper having a further improved surface feeling compared to conventional diapers.

  The present invention collectively injects 40 g of artificial urine into the central area of the skin facing surface of the disposable diaper, and after 20 seconds from the start of the injection, BT-Box (Bottom Temperature Box) is placed on the skin facing surface of the diaper. The amount of heat that is placed on the artificial urine injection part and moves from the BT-Box to the diaper under a load of 1.0 kPa is measured over time, and the maximum value of the measured heat transfer amount is 3 W or less. A disposable diaper is provided.

  The disposable diaper of the present invention has a high feeling of smoothness on the skin facing surface even when the liquid is absorbed.

  Hereinafter, the present invention will be described based on preferred embodiments thereof. The disposable diaper of the present invention widely includes what are called so-called unfolded diapers and pants-type diapers. The unfolded diaper includes a fastening tape on both left and right edges in one end region in the longitudinal direction of the diaper. The fastening tape is detachable from the outer surface in the other end region in the longitudinal direction of the diaper. The pants-type diaper has a crotch part and front and back body parts respectively extending forward and backward from the crotch part, and the left and right side regions of the front body and the left and right side regions of the back body are joined to each other. The pants-type structure has a waist opening and a pair of leg openings.

  The diaper of the present invention is disposed as a basic constituent member of a liquid-retaining absorbent, a surface sheet disposed on the skin facing surface side of the absorbent body, and a side opposite to the skin facing surface side of the absorbent body. And a back sheet. The diaper of this invention may be provided with members other than these members. For example, a leak-proof cuff extending in the longitudinal direction can be disposed on both sides of the diaper skin facing surface. In addition, an elastic member can be formed around the waist and / or around the legs in an extended state to fit the diaper to the wearer's body. Furthermore, an intermediate layer is provided between the top sheet and the absorbent for smoothly guiding the excreted liquid from the top sheet to the absorbent, and preventing the liquid absorbed by the absorbent from returning to the top sheet. Can be arranged.

  The diaper of the present invention is characterized by a high sensation of the skin facing surface even when the liquid is absorbed. As a result of the study by the present inventors, it was found that the smoothness of the skin facing surface can be evaluated by measuring the amount of heat transfer using BT-Box. The evaluation by this measurement is excellent in that a result closer to the bodily sensation can be obtained as compared with the above-described evaluation by q-max measurement.

BT-Box is well known in the art as a sensor used for measuring thermophysical properties. The BT-Box includes a hot plate that is a part that contacts the measurement object. The BT-Box includes means for supplying heat to the hot plate, for example, a heater, and a sensor for detecting the temperature of the hot plate so that the hot plate can always be kept at a set temperature. ing. In the present invention, as BT-Box, the one provided in THERMO LABO II (KES-F7), which is a precise rapid thermophysical property measuring apparatus manufactured by Kato Tech, is used. BT-Box is not a sensor for measuring q-max, but a sensor for measuring steady-state thermal conductivity. The area of the hot plate in this BT-Box is 25 cm ² .

FIG. 1 schematically shows the structure of the BT-Box in the KES-F7. The BT-Box 10 includes a hot plate 11 made of a metal such as aluminum. The surface of the hot plate 11 is exposed to the outside. The back surface of the hot plate 11 is held and fixed by a heat insulating material 12. A temperature sensor 13 is disposed between the back surface of the hot plate 11 and the heat insulating material 12. The temperature sensor 13 is a means for measuring the temperature of the hot platen 11. Further, a main heater 14 is embedded in the heat insulating material 12. The main heater 14 is a heating means for keeping the hot platen 11 at a set temperature. The heat insulating material 12 including the heat plate 11 is surrounded by the heat guard plate 15. The heat guard plate 15 is a member for preventing heat leakage through the heat insulating material 12. The entire heat guard 15 including the heat plate 11 and the heat insulating material 12 is held by the second heat insulating material 16. A sub-heater 17 and a second temperature sensor 18 are embedded in the second heat insulating material 16. The sub heater 17 is used to assist heating by the main heater 14 described above. The second temperature sensor 18 is for measuring the temperature of the sub heater 17. The main heater 14, the sub heater 17, the temperature sensor 13, and the second temperature sensor 18 are electrically connected to a control device (not shown), respectively.

In a control device (not shown), the temperature of the hot plate 11 of the BT-Box 10 is set. When the temperature of the hot platen 11 measured by the temperature sensor 13 falls below the set temperature, a command to heat the main heater 14 and the sub heater 17 is issued, and the temperature of the hot platen 11 is always kept at the set temperature. I am doing so. In the control device, the amount of heat required to keep the heat plate 11 at the set temperature is differentiated with time. By this differentiation operation, the amount of heat (W) required to keep the hot plate 11 at the set temperature is obtained as a function of time. The maximum value of the change in the amount of heat over time is the amount of heat focused in the present invention. For the purpose of normalizing the measurement result, a value (W / m ² ) obtained by dividing the heat quantity by the area (25 cm ² ) of the hot plate 11 may be expressed as heat quantity.

  The specific procedure for measuring the amount of heat of the diaper using the BT-Box having the above-described configuration will be described. First, the disposable diaper that is a measurement object is placed on the measuring table so that the skin facing surface faces upward. Place on top. As the measurement table, for example, a heat insulating material such as polystyrene foam can be used. Alternatively, a thermostatic device using gas or liquid as a heat medium can be used. When using a thermostatic device, the temperature is kept the same as the temperature of the measurement environment. There is no difference in the measurement results regardless of which measurement table is used. The measurement environment is a temperature of 23 ° C. and a relative humidity of 50%.

  In the above-described measurement environment, the disposable diaper that is a measurement object is acclimatized, and the hot plate 11 of the BT-Box 10 is heated to a set temperature and stabilized at that temperature. The set temperature is set to the temperature of the measurement environment plus 10 degrees, that is, 33 ° C. The reason for setting the temperature of the measurement environment plus 10 degrees is that a reproducible result can be obtained.

  Disposable diapers often have a stretchable gather that includes an elastic member for the purpose of realizing the functions required for it. The diaper is prone to wrinkles due to gather formation. The presence of soot may cause a decrease in accuracy in the measurement of heat using the BT-Box 10. In such a case, the diaper is placed on a flat base having a size slightly larger than that of the hot plate 11 of the BT-Box 10 so that the entire surface of the hot plate 11 of the BT-Box 10 is in contact with the diaper. It is preferable that the measurement is performed in a state where the ridges placed on the diaper are stretched on the pedestal. By adopting such a method, the accuracy of measurement is improved. If only wrinkles that do not hinder measurement are generated, it is not necessary to use the pedestal described above.

  Next, the BT-Box 10 is placed on the skin facing surface of the absorbent article so that the hot plate 11 comes into contact with the skin facing surface. At this time, by applying a predetermined weight to the BT-Box 10 in advance, the load applied to the absorbent article during measurement can be adjusted. Since the hot plate 11 is set and maintained at a temperature 10 degrees higher than that of the diaper, heat is transferred from the BT-Box 10 to the diaper due to the contact between the hot plate 11 and the temperature of the hot plate 11 is lowered. The control device connected to the BT-Box 10 issues a command to heat the heater in the BT-Box 10 in order to return the lowered temperature of the hot plate 11 to the set temperature. The amount of heat given to the hot plate 11 by the heating of the heater is equal to the amount of heat transferred from the hot plate 11 to the diaper. Therefore, by monitoring the amount of heat given to the hot plate 11 by the heating of the heater and differentiating the amount of heat with time, it is possible to know the temporal change of the amount of heat transferred from the hot plate 11 to the diaper, that is, the temporal change of the heat flow rate. it can. An example of the relationship between the heat flow rate and time thus obtained is shown in FIG.

  As shown in FIG. 2, the relationship between the heat flow rate obtained using the BT-Box 10 and time has a peak at the initial stage of measurement. After reaching the peak, the heat flow gradually decreases. This peak heat flow is defined as BT-maximum heat flow in the present invention. In the present invention that employs a disposable diaper as a measurement object, the time from the start of measurement until reaching the BT-maximum heat flow rate is generally within 10 seconds.

  In the same way that the value of q-max described in the background art section is a measure of the cold feeling of the measurement object, the value of the BT-maximum heat flow rate measured by the above method is also the cold temperature of the measurement object. It was confirmed by the present inventor that it is a measure of feeling. 3A and 3B are measurement results illustrating this.

As a model measurement object, an air-through nonwoven fabric often used as a surface sheet of a disposable diaper is adopted, and q-max value and BT-maximum heat flow value when the air-through nonwoven fabric absorbs various amounts of water. It was measured. Styrofoam was used as a measurement table. The air-through nonwoven fabric, which is a model measurement object, has a basis weight of 25 g / m ² and is composed of two types of core-sheath type composite fibers of PET / PE (2.0 dtex) and PP / PE (5.6 dtex). is there. The weight ratio of PET / PE and PP / PE is 2: 3. These fibers have been subjected to hydrophilic oil treatment. The q-max is as shown in FIG. 3A, and the q-max increased as the amount of water absorbed by the nonwoven fabric increased. This result is consistent with the description of Non-Patent Document 1 and Patent Document 1 described above. The BT-maximum heat flow rate is as shown in FIG. 3 (b), and as with q-max, the BT-maximum heat flow rate increased as the amount of water absorbed by the nonwoven fabric increased. From these results, it can be seen that the value of BT-maximum heat flow rate is a measure of the coolness of the disposable diaper, similar to the value of q-max.

  Next, the present inventors examined how much q-max and BT-maximum heat flow reflect the state of the disposable diaper in the depth direction. The results are shown in FIGS. 4 (a) and (b). These results are the results of measuring the q-max and the BT-maximum heat flow by superimposing the above-mentioned air-through nonwoven fabric on a stainless steel plate having a thickness of 2 mm. By examining how the values of q-max and BT-maximum heat flow change when the thickness is changed by changing the number of layers of the air-through nonwoven fabric, q-max and BT-maximum heat flow are It is possible to know how much the state of the disposable diaper in the depth direction is reflected. The thickness of the nonwoven fabric was measured with a laser thickness meter.

  Regarding q-max, as shown in FIG. 4A, the value of q-max is substantially constant regardless of the thickness of the nonwoven fabric. This means that q-max reflects only the state from the surface of the measurement object to a very shallow region. On the other hand, the BT-maximum heat flow rate is as shown in FIG. 4B, and the value of the BT-maximum heat flow rate is not constant unless the thickness of the nonwoven fabric is increased. This means that when the thickness of the nonwoven fabric is small, not only the nonwoven fabric but also the state of the stainless steel plate located thereunder is reflected in the BT-maximum heat flow rate. In other words, the BT-maximum heat flow rate can reflect the state from the surface of the measurement object to the deep region. In this respect, the BT-maximum heat flow is very useful compared to q-max.

In order to confirm that the result shown in FIG. 4B correlates with the bodily sensation, the present inventors performed the following experiment. An absorbent core was obtained by wrapping an absorbent core having a basis weight of 500 g / m ^{2 made} of a mixture containing 50% by weight of fluff pulp and 50% by weight of a superabsorbent polymer with thin paper having a basis weight of 16 g / m ² . A PE sheet having a basis weight of 20 g / m ² was used as the back sheet. On top of this, the above-mentioned air-through nonwoven fabric was layered to produce a model diaper. About this model diaper, q-max and BT-maximum heat flow in a state before absorbing the liquid were measured. The results are shown in FIGS. 5 (a) and (b). Next, the air-through nonwoven fabric was separated from the model diaper, and 40 g of artificial urine was directly injected into the absorber. After 1 minute from the injection of the artificial urine, the air-through nonwoven fabric was stacked on the absorbent body and returned to the model diaper state. Q-max and BT-maximum heat flow were measured for this model diaper. The results are shown in FIGS. 5 (a) and (b). The artificial urine used was 23 ° C., which is the same temperature as the measurement environment. Artificial urine was injected at a rate of 5 g / sec. The composition of artificial urine is 1.94% by weight of urea, 0.795% by weight of sodium chloride, 0.11% by weight of magnesium sulfate, 0.062% by weight of calcium chloride, 0.197% by weight of potassium sulfate, red No. 2 (dye ) 0.010% by weight, water 96.88% by weight and polyoxyethylene lauryl ether (about 0.07%), and the surface tension was adjusted to 53 ± 1 dyne / cm (23 ° C.).

  As is clear from the results shown in FIGS. 5A and 5B, it can be seen that the q-max value is almost the same in the measurement of q-max regardless of whether the model diaper is wet. On the other hand, in the measurement of the BT-maximum heat flow rate, it can be seen that the value of the BT-maximum heat flow rate is larger in the wet state than in the dry state.

  Separately from the measurements shown in FIGS. 5 (a) and 5 (b), for a model diaper in a dry state and in a wet state in which 40 g of artificial urine is directly absorbed by the absorber, five panelists are given air-through in the model diaper. The nonwoven fabric was touched and sensory evaluation of the degree of the wet state was carried out. The evaluation criteria were five levels: wet, slightly wet, wet, slightly wet, and dry. The result is shown in FIG. As is clear from this result, it can be seen that even if the surface is dry, if the absorbent body is moist, the diaper as a whole feels slightly wet.

  Comparing the results shown in FIG. 5 (c) with the results shown in FIGS. 5 (a) and 5 (b), it can be seen that the q-max measurement result does not correlate with the sensory evaluation. On the other hand, it can be seen that the measurement result of BT-maximum heat flow rate and sensory evaluation have a high correlation. From the above results, it can be seen that in the evaluation using q-max, if the top sheet of the diaper is dry, the entire diaper is determined to be dry even if the absorbent body is wet. On the other hand, in the evaluation using the BT-maximum heat flow rate, even if the surface sheet is dry, if the absorbent body is wet, it is determined that the entire diaper is wet. Therefore, by determining the wet state of the diaper using the BT-maximum heat flow rate, it is possible to accurately evaluate the subtle wetness felt by a person. In this respect, the diaper of the present invention developed on the basis of the BT-maximum heat flow rate has a very smooth surface feeling compared to the conventional diaper developed on the basis of the q-max. I understand.

  Next, the degree of correlation between the evaluation method of the present invention using the BT-maximum heat flow rate and sensory evaluation was examined. The absorbent article to be measured was the same as that used when the measurements shown in FIGS. 5A to 5C were performed. Into this absorbent article, 40 to 120 g of artificial urine was injected and left for 1 to 10 minutes to obtain several types of evaluation samples having different wet states. An experimental example will be given later for the amount of liquid to be injected and the change in the wet state depending on the elapsed time since the injection. The BT-maximum heat flow rate was measured using BT-Box adjusted so that a load of 1.0 kPa was applied from the surface sheet side of the absorbent article thus obtained. Separately from this measurement, four panelists were allowed to touch the surface sheet of the diaper for sensory evaluation of the degree of wetness. The evaluation criteria were the same as when the measurement shown in FIG. The result is shown in FIG.

  As is apparent from the results shown in FIG. 6, it can be seen that the value of the BT-maximum heat flow measured according to the present invention and the sensory evaluation correlate very well. Therefore, by evaluating the wet state of the diaper according to the value of the BT-maximum heat flow rate, it is possible to develop a novel disposable diaper having a high feeling of smoothness on the skin facing surface.

  In order to make a diaper with a high feeling even if the liquid is absorbed, the value of the BT-maximum heat flow rate measured according to the present invention may be reduced. As a result of the study by the present inventors, 40 g of artificial urine is collectively injected into the central region of the skin facing surface of the diaper. After 20 seconds from the start of the injection, BT-Box is artificially placed on the skin facing surface of the diaper. The value of BT-maximum heat flow rate placed on the urine injection part and measured by the above method under a 1.0 kPa load (hereinafter referred to as measurement condition 1) is 3 W or less, preferably 2.5 W or less. Further, it was found that a diaper having a sufficiently smooth feeling can be obtained by more preferably 2 W or less. In the range confirmed by the present inventors, the value of the BT-maximum heat flow rate measured under the above conditions for a conventional diaper is a high value of about 4 to 10 W.

  Measurement condition 1 corresponds to the state of the skin facing surface of the diaper immediately after excretion of the liquid. The amount of water remaining on the skin facing surface after the liquid is injected and completely absorbed can be evaluated by BT-maximum heat flow rate. On the other hand, if the state where the liquid is in contact with the skin continues, the skin swells and causes rash and the like. The shorter the time that the liquid is in contact with the skin, the more difficult it is to swell, and it is desirable that the amount of water remaining on the skin facing surface decreases within 1 minute, more preferably within 30 seconds. Moreover, from the result of the sensory evaluation shown in FIG. 6, if the BT-maximum heat flow rate is 3 W or less, it does not feel wet, and if it is 2 W or less, it feels sufficiently dry. I know. Therefore, a diaper having a small BT-maximum heat flow rate measured under a load of 1.0 kPa after 20 seconds from the above liquid injection hardly causes skin problems such as rash. The load of 1.0 kPa in measurement condition 1 corresponds to the pressure applied to the diaper when worn, for example, the pressure applied to the diaper while the infant is standing or walking when the infant is assumed to be the wearer. .

  Under measurement condition 1, artificial urine was injected at a rate of 5 g / sec using a tube pump. Injection | pouring was performed to the center area | region of the skin opposing surface of a diaper from the position of 10 mm on the skin opposing surface of a diaper.

  In the diaper of the present invention, the value of BT-maximum heat flow rate measured according to the above-described measurement condition 1 is as described above, and 80 g of artificial urine is injected into the central area of the diaper's skin facing surface in a lump. Then, 10 minutes after the start of injection, BT-Box is placed on the artificial urine injection part on the skin facing surface of the diaper and is described above under a 3.5 kPa load (hereinafter referred to as measurement condition 2). The value of BT-maximum heat flow rate measured by the method is preferably 2 W or less, particularly 1.8 W or less, particularly 1.6 W or less. The measurement condition 2 corresponds to the state of the skin facing surface of the diaper after a lapse of a certain time after the liquid is excreted. In particular, 3.5 kPa, which is the load in the measurement condition 2, corresponds to the pressure applied to the diaper when the infant is assumed to be a wearer, for example, the pressure applied to the diaper while the infant is sitting. The smaller the value of BT-maximum heat flow measured according to measurement condition 2, the smaller the amount of liquid that adheres to the skin when the wearer's skin touches the skin-facing surface of the diaper after the liquid is excreted.

  The diaper of the present invention has 40 g of artificial urine in the central region of the skin facing surface of the diaper in addition to, or instead of, the value of BT-maximum heat flow rate measured in accordance with the above-described measurement condition 2. 3 minutes after the start of injection, pressurize for 2 minutes under a load of 3.5 kPa, and after another 5 minutes, inject 40 g of artificial urine at the same position all at once. After 3 minutes, pressurize for 2 minutes under a 3.5 kPa load, place BT-Box on the artificial urine injection part on the skin facing surface of the diaper, and under 3.5 kPa load (hereinafter, this condition is measured) It is preferable that the value of BT-maximum heat flow rate measured by the above-described method under condition 3) is 3 W or less, particularly 2.5 W or less, particularly 2 W or less. The measurement condition 3 corresponds to the state of the skin facing surface of the diaper after a lapse of a certain time after the liquid is excreted. In this respect, the measurement condition 3 is equal to the measurement condition 2 described above. However, the difference between the two is that the measurement condition 2 corresponds to the state of the skin-facing surface of the diaper after a lapse of a certain time after a large amount of liquid is excreted all at once. 3 is a point corresponding to the state of the skin facing surface of the diaper after a small amount of liquid is repeatedly excreted under the measurement condition 2 and the infant's load is repeatedly applied to the diaper. Measurement condition 3 is a condition that is easier to wet than measurement condition 2. As with measurement condition 2, the smaller the value of BT-maximum heat flow measured in accordance with measurement condition 3, the more liquid that adheres to the skin when the wearer's skin touches the skin-facing surface of the diaper after the liquid is excreted. The amount of.

  In measurement conditions 2 and 3, the procedure for injecting artificial urine into the diaper is the same as in measurement condition 1.

As a design method of a new diaper satisfying the above-described measurement conditions 1 to 3, for example, the following (I) to (IV) are listed.
(I) The structure which moves away the excreted liquid from the skin facing surface of a diaper quickly is employ | adopted.
(II) A configuration that reduces the contact area between the wearer's skin and the diaper skin facing surface is adopted.
(III) A configuration that reduces liquid residue on the skin facing surface of the diaper is adopted.
(IV) A configuration is adopted in which the amount of liquid absorbed by the diaper absorber is reduced back toward the skin facing surface.

  By adopting the design method (I) or (II), a new diaper that satisfies the value of BT-maximum heat flow rate measured mainly under the measurement conditions 1 and 2 can be obtained. Further, by adopting the design method of (III), a new diaper that satisfies the value of BT-maximum heat flow rate measured mainly under measurement condition 2 can be obtained. Furthermore, by adopting the design method (IV) described above, a new diaper that satisfies the value of BT-maximum heat flow rate measured mainly under the measurement condition 3 can be obtained.

Specific diaper configurations based on the design method (I) include the configurations (a) to (c) below. Specific diaper configurations based on the design method (II) include the following configurations (d) and (e). Specific diaper configurations based on the design method (III) include the following configurations (f) and (g). As a specific diaper configuration based on the design method (IV) described above, the following configuration (H) may be mentioned.
(A) A capillary force gradient is provided between the top sheet and the intermediate layer.
(B) A material having high water absorption is disposed under the top sheet or under the intermediate layer.
(C) A hydrophobic-hydrophilic gradient is provided between the top sheet and the intermediate layer.
(D) Make the surface of the surface sheet uneven.
(E) The superabsorbent polymer contained in the absorber is distributed unevenly.
(F) The surface sheet is made to have a low basis weight, embossed, or an aperture is formed.
(G) Make the entire surface or part of the top sheet water-repellent.
(H) Make the intermediate layer bulky, or roughen the intermediate layer using thick fibers.

As a particularly preferable configuration of the diaper of the present invention based on the above design method, the following embodiments (a) to (c) are exemplified.
(A) The surface sheet is composed of a sheet in which a large number of irregularities are dispersedly arranged on the skin facing surface side, and the intermediate layer is composed of an air-through nonwoven fabric.
(B) The topsheet is made of a sheet in which a number of irregularities are dispersedly arranged on the skin facing surface side, and the intermediate layer is a layer of an air-through nonwoven fabric located on the topsheet side, and a layer of spunlace nonwoven fabric located on the absorber side The spunlace nonwoven fabric comprises rayon as a constituent fiber.
(C) The top sheet is composed of a sheet in which a large number of irregularities are dispersedly arranged on the skin facing surface side, and the intermediate layer is composed of a nonwoven fabric layer located on the top sheet side and a crosslinked fiber layer located on the absorber side. Constitution.

  The above preferable structure has a characteristic in the member located in the side close | similar to a wearer's skin among the various members which comprise a diaper. By adopting a configuration other than these configurations (for example, by devising the configuration of the absorbent body), it is possible to obtain a diaper having a light feeling. However, the BT-maximum heat flow rate, which is an index of dryness adopted in the present invention, is information on the depth from the skin facing surface of the diaper to several millimeters as described in FIG. Therefore, it is advantageous to devise a member located on the side close to the skin of the wearer because the information obtained from the BT-maximum heat flow is surely reflected in the smooth feeling of the diaper. is there.

  Hereinafter, the diaper of embodiment which has the structure of the above-mentioned (a) thru | or (c) is each demonstrated. The configuration (a) is based on the design concept of reducing the contact area with the skin and further reducing the liquid return amount from the absorber. (A) The sheet | seat with which many unevenness | corrugations are distributedly arranged by the skin opposing surface side used as a surface sheet in the structure of (a) consists of a conjugate | zygote of an upper layer fiber sheet and a lower layer fiber sheet, and the three-dimensional shaping of an upper layer fiber sheet The composite sheet has a large number of convex portions made of an upper-layer fiber sheet on a substantially flat lower fiber sheet and has concave portions between the convex portions. The concave portions and the convex portions in the composite sheet are alternately arranged in one direction of the composite sheet, and are also alternately arranged in a direction orthogonal to the direction.

  The concavo-convex shaped composite sheet 1 shown in FIG. 7 is composed of two sheets. The composite sheet 1 has an upper fiber sheet 2 as a first sheet-like material directed toward the skin side of the wearer and a lower fiber sheet 3 as a second sheet-like material arranged on the absorber side. . The upper fiber sheet 2 and the lower fiber sheet 3 are typically composed of various nonwoven fabrics and films. As a nonwoven fabric, the nonwoven fabric manufactured by the card | curd method, the spun bond nonwoven fabric, the melt blown nonwoven fabric, the spunlace nonwoven fabric, the needle punch nonwoven fabric etc. are mentioned, for example. When a film is used, it is preferable to perforate the film to provide a large number of holes so that the liquid can be permeated.

  A composite sheet 1 shown in FIG. 7 is composed of a joined body of an upper fiber sheet 2 and a lower fiber sheet 3. The composite sheet 1 has a large number of convex portions 5 formed of the upper layer fiber sheet 2 on the substantially flat lower layer fiber sheet 3 by the three-dimensional shaping of the upper layer fiber sheet 2, and a concave portion between the convex portions 5. 6. The upper layer fiber sheet 2 and the lower layer fiber sheet 3 are partially joined at a large number of joints 4. The upper fiber sheet 2 protrudes toward the wearer's skin side, thereby forming the convex portion 5. The inside of the convex portion 5 is hollow, that is, hollow. A concave portion 6 is formed between the adjacent convex portions 5.

  The concave portions 5 and the convex portions 6 are alternately arranged in the X direction shown in FIG. At the same time, the concave portions 5 and the convex portions 6 are alternately arranged in the Y direction, which is a direction orthogonal to the X direction. When the composite sheet 1 is viewed in plan from the upper-layer fiber sheet 2 side, the convex portions 5 and the concave portions 6 are arranged in a staggered pattern (see FIG. 8 described later). By arranging the convex portion 5 and the concave portion 6 in this way, liquid leakage is extremely effectively prevented in the disposable diaper including the composite sheet 1. In detail, when the composite sheet 1 is used as a top sheet of a diaper for a low-age child who excretes loose stool, which is excretion with high viscosity, for example, the following effects are exhibited. Since soft stool has a high viscosity, it is generally difficult to permeate the surface sheet quickly and stays on the surface sheet and tends to cause a lateral flow. On the other hand, if the composite sheet 1 of this embodiment is used, since the soft stool is captured in the closed recessed part 6 surrounded and formed by the convex part 5, it becomes difficult to produce a lateral flow. Moreover, the downward movement (that is, the absorber direction) is promoted due to the trapping. As a result, leakage of soft stool is prevented. Moreover, since the convex part 5 has a hollow inside, it has a concealing effect that the color of soft stool absorbed by the absorbent body is reduced when viewed from the surface sheet side.

  The convex part 5 is a flat rectangular parallelepiped, a hemisphere, or a truncated quadrangular pyramid with rounded ridgelines as a whole. The convex part 5 has a pair of 1st wall part 51 located along the X direction shown in FIG. Moreover, the convex part 5 has a pair of 2nd wall part 52 located along the Y direction which is a direction orthogonal to a X direction, and mutually opposing. Furthermore, the convex portion 5 has a top surface portion 53 that is continuous with the upper side of each first wall portion 51 and the upper side of each second wall portion 52. Further, the convex portion 5 has a bottom surface portion 54 that is a surface facing the top surface portion 53. The first wall 51, the second wall 52 and the top surface 53 are composed of the upper layer 2. On the other hand, the bottom surface portion 54 is composed of the lower layer 3.

  FIG. 8 shows a plan view of the composite sheet 1 shown in FIG. In FIG. 8, with respect to the X direction and the Y direction, the joints 4 are formed in a staggered arrangement pattern. The position of the joint portion 4 becomes the concave portion 6 in the composite sheet 1. Accordingly, the recesses 6 are formed in a staggered array pattern. In other words, the recesses 6 are arranged in a row with respect to the X direction and the Y direction. When attention is paid to the row of the recesses 6 along the X direction, the arrangement of the recesses 6 is shifted by a half pitch in the adjacent row. The same applies to the Y direction. When attention is paid to the row of the recesses 6 along the Y direction, the arrangement of the recesses 6 is shifted by a half pitch in the adjacent row.

  As shown in FIG. 8, the region surrounded by the four joint portions 4 a, 4 b, 4 c, and 4 d that are the four corners of the rhombus of the joint portion 4 is a convex portion 5. The protrusions 5 are also formed in a staggered array pattern. The convex portions 5 form a row with respect to the X direction and the Y direction. When attention is paid to the rows of convex portions 5 along the X direction, the arrangement of the convex portions 5 is shifted by a half pitch in the adjacent rows. The same applies to the Y direction. When attention is paid to the row of the convex portions 5 along the Y direction, the arrangement of the convex portions 5 is shifted by a half pitch in the adjacent row.

  As is clear from FIG. 8, each convex portion 5 does not exist independently independently, but is oblique with respect to the X direction (and Y direction) when attention is paid to any one convex portion 5. It connects with the two convex parts 5 located in the front, and the two convex parts 5 located diagonally backward. The height of the connecting portion between the convex portions 5 is the same level as or lower than the height of the top portion of the convex portions 5. On the other hand, regarding the recessed part 6, each recessed part exists separately independently.

It is preferable that the height H (refer FIG. 7) of the convex part 5 is 0.3-10 mm, especially 0.7-5 mm. Moreover, it is preferable that the bottom part dimension A of the convex part 5 along a X direction (MD) is 1.5-30 mm, especially 2-5 mm. The bottom dimension B along the Y direction (CD) is preferably 1.5 to 30 mm, particularly preferably 2 to 10 mm. Further, it is preferable that the bottom area of the projection 5 is 2.25～900Mm ^2, especially 4~50mm ^2.

  The suitable manufacturing method of the uneven | corrugated shaped composite sheet 1 which has the above structure is described in Unexamined-Japanese-Patent No. 2004-174234 and Unexamined-Japanese-Patent No. 2005-111908 which concern the previous application of this applicant, for example.

  Moreover, the 1st fiber layer used as the skin opposing side as a sheet | seat by which many unevenness | corrugations are distributedly arranged by the skin opposing surface side used suitably as a surface sheet in the structure of (a), and the 2nd fiber adjacent to this And the two layers are partially joined at a large number of joints of a predetermined pattern and integrated in the thickness direction, and heat shrinkage of the second fiber layer between the joints. A three-dimensional sheet in which the first fiber layer protrudes in a convex shape and a large number of irregularities are formed on the surface on the first fiber layer side may be used.

  An example of such a three-dimensional sheet is shown in FIGS. The three-dimensional sheet 10 has a two-layer structure having a first fiber layer 21 including one surface and a second fiber layer 22 including the other surface. The 1st fiber layer 21 and the 2nd fiber layer 22 consist of fiber aggregates, respectively, are mutually laminated, and are joined partially. As shown in the figure, the joint 23 between the first fiber layer 21 and the second fiber layer 22 is consolidated by the action of heat and / or pressure, and has a thickness smaller than that of the other part of the three-dimensional sheet 10 and has a density. Is high. As a result, on the first fiber layer 21 side, there are a large number of convex portions 24 dispersedly arranged in a predetermined pattern and a large number of concave portions 25 formed on the joint portion 23, and these convex portions 24. And the uneven | corrugated shape is formed in the surface of the 1st fiber layer 21 of the three-dimensional sheet 10 by the recessed part 25. FIG. Here, as a pattern of unevenness, as long as it has a good wearing feeling, in addition to the substantially same point shape shown in FIG. 9A, a combination of a plurality of shapes such as ellipses of different sizes and longitudinal ridges may be used. Well, random patterns can also be constructed. The inside of the convex part 24 is filled with fibers. The surface on the first fiber layer 21 side is used as a skin contact surface in the surface sheet. Unlike the surface of the first fiber layer 21, the surface of the second fiber layer 22 is generally flat.

The thickness T1 (see FIG. 9B) of the convex portion 24 in the three-dimensional sheet 10 is preferably set to 1 to 30 mm, particularly 1 to 10 mm. Moreover, it is preferable to set thickness T2 (refer FIG.3 (b)) of the recessed part 25 to 0.01-5 mm, especially 0.1-1 mm. It is also preferable to set the ratio of T1 / T2 to 2 to 50, particularly 2 to 20. Furthermore, from the same viewpoint, the area ratio of the joint portion 23 to the area of the three-dimensional sheet 10 (ratio of the area of the joint portion 23 per unit area of the three-dimensional sheet 10) is preferably 3 to 50%, and preferably 5 to 35%. More preferably. The area of the joint 23 itself is preferably 0.1 to ⁵ mm ² , particularly preferably 0.1 to ¹ mm ² . The shortest distance between adjacent convex portions 24 (the distance from the center of the convex portion to the center of the adjacent convex portion) is preferably 0.5 to 15 mm, particularly preferably 1 to 10 mm.

  If the constituent fiber of each fiber layer which comprises the solid sheet 10 is demonstrated, the 2nd fiber layer 22 will contain the solid crimped fiber. In general, a three-dimensional crimped fiber exhibits a coiled (spiral) crimp. The three-dimensional crimped fiber is preferably a latent crimped fiber in which crimps are expressed. The 2nd fiber layer 22 may be comprised only from the solid crimped fiber, or may contain the other fiber. Examples of other fibers include ordinary thermoplastic fibers, regenerated fibers such as rayon, and natural fibers such as cotton. When other fibers are included in addition to the three-dimensional crimped fibers, the blending amount of the other fibers may be 1 to 50% by weight, particularly 5 to 30% by weight, based on the entire second fiber layer 22. preferable. On the other hand, examples of the constituent fibers of the first fiber layer 21 include ordinary thermoplastic fibers, regenerated fibers such as rayon, and natural fibers such as cotton. Moreover, the 1st fiber layer 21 may contain the solid crimped fiber. In particular, the first fiber layer 21 is made of a thermoplastic polymer material and has substantially no heat shrinkability, or is made of a fiber that does not heat shrink below the heat shrink temperature of the latent crimpable fiber, or the fiber. It is preferable to contain.

  A preferred method for producing the three-dimensional sheet 10 is as follows. First, the fiber assembly which comprises the 1st fiber layer 21 and the 2nd fiber layer 22 is manufactured, respectively. As such a fiber assembly, for example, a web or a nonwoven fabric can be used. A nonwoven fabric is manufactured by the air through method, the heat roll method (heat embossing method), the airlaid method, the melt blown method etc., for example. The web is manufactured by a card machine, for example. In particular, it is preferable to use a nonwoven fabric or a web as the fiber aggregate constituting the first fiber layer 21 and to use a web as the fiber aggregate constituting the second fiber layer 22.

  The web constituting the second fiber layer 22 preferably contains latent crimped fibers. Latent crimped fibers can be handled in the same way as ordinary non-woven fabric fibers before being heated, and the coiled (spiral) three-dimensional crimp is developed and contracted by heating at a predetermined temperature. It is the fiber which has. The latent crimped fiber is composed of, for example, an eccentric core-sheath type composite fiber or a side-by-side type composite fiber containing two types of thermoplastic polymer materials having different shrinkage rates as components. As the latent crimped fiber in which the three-dimensional crimp is manifested by heating, for example, a latent crimpable fiber CPP (trade name) manufactured by Daiwa Boseki Co., Ltd. can be used.

  Next, the fiber assembly constituting the first fiber layer 21 is overlapped on the fiber assembly constituting the second fiber layer 22, and these are partially joined in a predetermined pattern. Various methods can be used as a method for bonding the two as long as the bonding portion 23 in which the thickness of the first fiber layer 21 is reduced more than other portions can be formed. For example, hot embossing or ultrasonic embossing is preferable. The joints 23 may be in the form of scattered dots that are independent from each other, or may be linear, curved (including continuous waveforms, etc.), lattice, zigzag, or the like. The shape of each joint 23 when the joints 23 are arranged in the form of dots can be any shape such as a circular shape, a triangular shape, or a quadrangular shape. In this case, the arrangement pattern of the joints 23 can be in the form of a rhombus, for example, as shown in FIG.

  Heat is applied to the bonded first fiber layer 21 and the second fiber layer 22, and the latent crimped fibers contained in the second fiber layer 22 are three-dimensionally crimped into a coil shape (spiral shape). The temperature of the heat to be applied is equal to or higher than the temperature at which the latent crimped fiber included in the second fiber layer 22 starts to shrink. For example, a method of blowing hot air by an air-through method can be used for applying heat. By this crimping, the constituent fibers of the second fiber layer 22 located between the joint portions 23 contract. Thereby, the second fiber layer 22 contracts in the in-plane direction. On the other hand, the constituent fibers of the first fiber layer 21 do not shrink. Therefore, the contraction of the second fiber layer 22 in the in-plane direction causes the constituent fibers of the first fiber layer 21 located between the joint portions 23 to lose their place in the plane direction and move in the thickness direction. Thereby, the space between the joint portions 23 is raised, and a large number of convex portions 24 are formed on the first fiber layer 21 side. Moreover, the recessed part 25 is formed between the convex parts 24, ie, the position of the junction part 23. FIG. In this way, the three-dimensional sheet 10 having a concavo-convex shape on the surface on the first fiber layer 21 side is obtained.

The air-through nonwoven fabric used as the intermediate sheet in the configuration of (a) is obtained by blowing hot air onto a fiber web in a penetrating manner and fusing the intersections of the fibers on the web. As constituent fibers of the air-through nonwoven fabric, those made of various thermoplastic resins are used. Specifically, it consists of a single material fiber made of a polyolefin resin such as polyethylene or polypropylene, a polyester resin such as polyethylene terephthalate, a vinyl resin or an acrylic resin, or a combination of two or more of these resins. Examples include composite fibers (for example, core-sheath type composite fibers and side-by-side type composite fibers). These fibers have a fineness of 2 to 20, particularly 5 to 15 dtex, and a basis weight of 10 to 100 g / m ² , particularly 20 to 50 g / m ^2. From the viewpoint that the liquid hardly remains on or inside the sheet. Further, for example, an air laid nonwoven fabric can be used instead of the air-through nonwoven fabric.

  The configuration of (b) is based on the design concept of reducing the contact area with the skin as in the configuration of (a), reducing the amount of liquid return from the absorber, and quickly moving the liquid away from the skin surface. Is. As the topsheet in the configuration of (b), the same topsheet as in the configuration of (a) described above is used.

  The intermediate sheet in the configuration of (b) has a two-layer structure including a layer located on the top sheet side and a layer located on the absorber side. The layer located on the top sheet side is composed of an air-through nonwoven fabric layer. As this air through nonwoven fabric, the thing similar to the intermediate sheet in the structure of (a) demonstrated previously can be used. As with the configuration of (a), an airlaid nonwoven fabric may be used instead of the air-through nonwoven fabric.

  The layer located on the absorber side in the intermediate sheet is composed of a spunlace nonwoven fabric layer. The spunlace nonwoven fabric is formed by spraying various fluids such as water onto a fiber web and entangle the constituent fibers of the fiber web into a sheet. This spunlace nonwoven fabric contains rayon as a constituent fiber. By using rayon as the constituent fiber, there is an advantageous effect that water absorption is improved.

  The spunlace nonwoven fabric may be composed of only rayon, or may be composed of other fibers in addition to rayon. When the spunlace nonwoven fabric contains other fibers, examples of the other fibers include fibers made of various thermoplastic resins and cellulose fibers other than rayon. As fibers made of thermoplastic resin, polyolefin resin such as polyethylene and polypropylene, polyester resin such as polyethylene terephthalate, single material fiber made of vinyl resin, acrylic resin, etc., or two or more of these resins Or a composite fiber (for example, a core-sheath type composite fiber or a side-by-side type composite fiber). When other fibers are contained in the spunlace nonwoven fabric in addition to the rayon, the other fibers are preferably contained in the spunlace nonwoven fabric in an amount of 10 to 60% by weight, particularly 20 to 50% by weight.

The spunlace nonwoven fabric preferably has a basis weight of 10 to 80 g / m ² , particularly 30 to 50 g / m ^{2 from the} viewpoint of quickly absorbing the liquid and not holding the absorbed liquid too much.

  The air-through non-woven fabric and the spunlace constituting the intermediate sheet may have a one-ply structure joined by a known joining means such as an adhesive or the like, or may not be joined.

  In the configuration of (b) described above, the concavo-convex shaped composite sheet constituting the surface sheet and the air-through nonwoven fabric layer located on the surface sheet side in the middle are joined by a known joining means such as an adhesive. May or may not be joined.

  The configuration of (c) reduces the contact area with the skin as in the configuration of (b), reduces the amount of liquid return from the absorber, and quickly moves the liquid away from the skin surface, and also the wearer's body. This is based on the design philosophy of making the surface sheet difficult to be crushed even when pressure is applied.

The intermediate layer in the configuration of (c) has a two-layer structure including a layer located on the top sheet side and a layer located on the absorber side, like the intermediate sheet in the configuration of (b) described above. It is. The layer located on the top sheet side is made of nonwoven fabric. As a nonwoven fabric, the thing similar to what was conventionally used in the said technical field can be used. Examples of such a nonwoven fabric include an air-through nonwoven fabric and an airlaid nonwoven fabric. In particular, it is preferable to use a resin bond nonwoven fabric as the nonwoven fabric. The resin-bonded nonwoven fabric is obtained by applying a binder to a fiber web and bonding the intersections of fibers on the web with the binder. As a constituent fiber of this resin bond nonwoven fabric, what consists of various thermoplastic resins is used. Specifically, it consists of a single material fiber made of a polyolefin resin such as polyethylene or polypropylene, a polyester resin such as polyethylene terephthalate, a vinyl resin or an acrylic resin, or a combination of two or more of these resins. Examples include composite fibers (for example, core-sheath type composite fibers and side-by-side type composite fibers). These fibers have a fineness of 2 to 20, particularly 5 to 15 dtex, and a basis weight of 10 to 100 g / m ² , particularly 20 to 70 g / m ² , so that the liquid can easily pass through. It is preferable from the viewpoint that the liquid hardly remains on or inside the sheet and the top sheet is not easily crushed.

  The layer located on the absorber side in the intermediate sheet is mainly composed of a fiber assembly including crosslinked fibers. As the cross-linked fiber, individual cross-linked fibers, that is, fibers having chemical cross-links in the fibers (hereinafter also referred to as individual cross-linked fibers) are preferable. Examples of the types of fibers to be crosslinked include pulp and rayon, and cellulose fibers such as pulp are particularly preferable. Layers made from individualized cross-linked fibers generally have the advantage of high resiliency when wet and dry compared to the structure of layers made from non-cross-linked fibers.

  The method for producing the individualized crosslinked fibers is not particularly limited, and examples thereof include the methods described as the dry crosslinking method, the aqueous solution crosslinking method, and the nonaqueous solution crosslinking method described in Japanese Patent No. 3247386. The dry cross-linking method is, for example, a method described in US Pat. No. 3,224,926, in which a cellulose dry wrap is sprayed with a cross-linking agent, the fibers are separated by mechanical action, and the fibers are in a substantially individual state. This is a method for obtaining a crosslinked fiber by drying the fiber at a high temperature to cause crosslinking. Fibers by dry crosslinking are generally very stiff due to cross-linking, and the structure of the layers made therefrom exhibits a relatively high elastic recovery. The aqueous solution crosslinking method is a method described in, for example, US Pat. No. 3,241,553, and is a method for obtaining crosslinked fibers by crosslinking fibers in an aqueous solution containing a crosslinking agent and a catalyst. The non-aqueous solution crosslinking method is, for example, a method described in US Pat. No. 4,035,147, in which a crosslinking agent and a catalyst are dehydrated in a substantially non-aqueous solution containing an insufficient amount of water to swell the fibers. This is a method for obtaining a crosslinked fiber by bringing it into contact with the formed non-swelled fiber.

  Examples of the crosslinking agent for forming intrafiber crosslinks on cellulose fibers include formaldehyde and / or formaldehyde addition products, dialdehyde crosslinking agents, and polycarboxylic acids. Examples of the crosslinking agent are described in, for example, the above-mentioned Japanese Patent No. 3247386.

  The layer located on the absorber side in the intermediate sheet may be composed of individualized crosslinked fibers or may include fibers other than individualized crosslinked fibers. The proportion of the individualized crosslinked fibers is preferably 10% by weight or more, particularly 15 to 25% by weight, based on the total amount of fibers in the layer.

  The layer located on the absorber side of the intermediate sheet may be composed of the above-described fiber accumulation structure, or the accumulation structure may be covered with a liquid-permeable sheet such as thin paper. Further, the layer located on the absorber side in the intermediate sheet and the layer located on the surface sheet side may be joined by known joining means such as an adhesive or the like, or may not be joined. .

  In the configuration of (c) described above, the sheet constituting the top sheet and the non-woven fabric layer located on the side of the top sheet may be joined by a known joining means such as an adhesive. Or it may not be joined.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” and “part” mean “% by weight” and “part by weight”, respectively.

[Example 1]
A disposable diaper was manufactured according to a conventional method using the following members (1-1) to (4-1).
(1-1) Surface sheet An air-through nonwoven fabric having a basis weight of 18 g / m ² was used as the upper fiber sheet. An air-through nonwoven fabric having a basis weight of 18 g / m ² was used as the lower fiber sheet. Using these non-woven fabrics, a concavo-convex shaped composite sheet having the structure shown in FIG. 7 was produced by the apparatus described in Japanese Patent Application Laid-Open No. 2005-111908 according to the previous application of the present applicant. The convex part in this uneven shaped sheet has a height H of 13 mm, a bottom dimension A of the convex part along the X direction (MD) of 3 mm, and a bottom dimension B along the Y direction (CD) of 3 mm. The bottom area was 9 mm ² .
(2-1) Intermediate layer An air-through nonwoven fabric having a basis weight of 40 g / m ² was used as the intermediate layer. The constituent fibers consisted of two types of core-sheath type composite fibers of PP / PE and PET / PE.
(3-1) Absorber An absorbent core having a basis weight of 500 g / m ² was produced from a mixture of fluff pulp and superabsorbent polymer particles. The weight ratio of fluff pulp to superabsorbent polymer particles in the absorbent core was 5: 7. The absorbent core was covered with a thin paper having a basis weight of 16 g / m ² to obtain an absorbent body.
(4-1) Back Sheet A PE resin film (basis weight 20 g / m ² ) was used as the back sheet.

[Example 2]
A disposable diaper was obtained in the same manner as in Example 1 except that the following member (1-2) was used as the top sheet.
(1-2) Surface sheet A card web having a basis weight of 22 g / m ² was used as the first fiber layer. The constituent fibers consisted of PET / PE core-sheath type composite fibers. A card web having a basis weight of 22 g / m ² was used as the second fiber layer. The constituent fibers consisted of latent spiral crimped fibers (CPP fibers (trade name) manufactured by Daiwa Spinning). The first fiber layer and the second fiber layer were overlapped and partially joined by an ultrasonic embossing method. The joint part was circular, and the rhombus lattice pattern shown in FIG. 9A was formed as a whole. After joining the two, hot air of 130 ° C. ± 10 ° C. is passed for 5 to 10 seconds to crimp the latent spiral crimped fiber of the second fiber layer to shrink the second fiber layer and the first fiber between the joints The layer was protruded in a convex shape, and a three-dimensional sheet having a large number of convex portions shown in FIGS. 9A and 9B was manufactured. The inside of the portion where the first fiber layer protruded in a convex shape was filled with fibers. The area ratio of the joint portion in the obtained three-dimensional sheet was 7.3%. The thickness T1 at the convex portion was 2.0 mm, and the thickness T2 at the concave portion 25 was 0.8 mm.

Example 3
A disposable diaper was obtained in the same manner as in Example 1 except that the above (1-1) member was used as the top sheet and the following (2-3) member was used as the intermediate layer.
(2-3) Intermediate layer The intermediate layer had a two-layer structure of an air-through nonwoven fabric layer located on the top sheet side and a spunlace nonwoven fabric layer located on the absorber side. As the air-through nonwoven fabric, the above-described member (2-1) was used, and the spunlace nonwoven fabric having a basis weight of 40 g / m ² was used. The constituent fibers consisted of a 7: 3 weight ratio of rayon and PET. The air-through nonwoven fabric and the spunlace nonwoven fabric were joined with a discontinuously applied hot melt adhesive (basis weight 3 g / m ² ).

Example 4
A disposable diaper was obtained in the same manner as in Example 1 except that the above (1-1) member was used as the top sheet and the following (2-4) member was used as the intermediate layer.
(2-4) Intermediate layer The intermediate layer had a two-layer structure of a resin bond nonwoven fabric layer located on the top sheet side and a crosslinked fiber layer located on the absorber side. The resin bond nonwoven fabric had a basis weight of 60 g / m ² , and the constituent fibers were made of PET resin. The resin-bonded nonwoven fabric and the cross-linked fiber layer were joined with a discontinuously applied hot melt adhesive (basis weight 3 g / m ² ).

[Comparative Examples 1 to 3]
A commercially available diaper was used as a comparative example. Comparative Example 1 is Marys (registered trademark) smooth air-through, M size (U512127) manufactured by Kao Corporation, and Comparative Example 2 is Pampers (registered trademark) cotton care, M size (7234 202235) manufactured by Procter & Gamble. 13:23 2007 0822), and Comparative Example 3 is Mooney (registered trademark) Sarah Magic, M size (710018083) manufactured by Unicharm.

[Evaluation]
About the diaper obtained by the Example and the comparative example, BT-maximum heat flow was measured on the measurement conditions 1-3 mentioned above. Moreover, about those diapers, five panelists touched the surface sheet by the hand under the measurement conditions 1 thru | or 3, and made the sensory evaluation of the wet state. The evaluation criteria were five levels: wet, slightly wet, wet, slightly wet, and dry. These results are shown in Table 1 below.

  As is apparent from the results shown in Table 1, the diaper of the example (product of the present invention) in which the BT-maximum heat flow rate under each measurement condition is not more than a specific value is judged to be dry in the sensory evaluation. Has been. On the other hand, it can be seen that the diaper of the comparative example having a large value of BT-maximum heat flow rate has a high wet feeling.

FIG. 1 is a schematic diagram showing the structure of a BT-Box. FIG. 2 is a graph showing a change in heat flow with time. Fig.3 (a) is a graph which shows the relationship between q-max and a moisture content, and FIG.3 (b) is a graph which shows the relationship between BT-maximum heat flow rate and a moisture content. 4A is a graph showing the relationship between q-max and the thickness of the measurement object, and FIG. 4B is a graph showing the relationship between BT-maximum heat flow rate and the thickness of the measurement object. is there. FIG. 5A is a graph showing q-max values in dry and wet diapers, and FIG. 5A is a graph showing BT maximum heat flow values in dry and wet diapers. FIG. 5 (c) is a graph showing the results of sensory evaluation for wetting in dry and wet diapers. FIG. 6 is a graph showing the correlation between BT-maximum heat flow rate and sensory evaluation in various wetted diapers. FIG. 7 is an enlarged view of a main part showing a surface sheet suitably used in the present invention. FIG. 8 is a plan view of the topsheet shown in FIG. Fig.9 (a) is a principal part enlarged view which shows another surface sheet used suitably for this invention, FIG.9 (b) is a longitudinal cross-sectional view of the surface sheet shown to Fig.9 (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Concavo-concave shaping composite sheet 2 Upper layer fiber sheet 3 Lower layer fiber sheet 4 Joint part 5 Convex part 6 Concave part

Claims (9)

  40 g of artificial urine is collectively injected into the central area of the skin facing surface of the disposable diaper, and after 20 seconds from the start of the injection, BT-Box (Bottom Temperature Box) is injected into the artificial urine injection portion on the skin facing surface of the diaper. A disposable diaper that is placed on top, measures the amount of heat transferred from the BT-Box to the diaper under a load of 1.0 kPa over time, and the maximum value of the measured heat transfer amount is 3 W or less.   80 g of artificial urine is injected into the central area of the skin facing surface of the diaper in a lump, and after 10 minutes from the start of injection, BT-Box is placed on the artificial urine injection part on the skin facing surface of the diaper. The disposable diaper according to claim 1, wherein the amount of heat transferred from the BT-Box to the diaper under a 3.5 kPa load is measured over time, and the maximum value of the measured heat transfer amount is 2 W or less.   Inject 40 g of artificial urine into the central area of the diaper's skin facing surface, pressurize for 2 minutes under a load of 3.5 kPa after 3 minutes from the start of injection, and 40 g at the same position after 5 minutes. Inject artificial urine all at once, and after 3 minutes from the start of reinjection, pressurize for 2 minutes under a load of 3.5 kPa, and place BT-Box on the artificial urine injection part on the skin facing surface of the diaper The disposable amount according to claim 1 or 2, wherein the amount of heat transferred from the BT-Box to the diaper under a 3.5 kPa load is measured over time, and the maximum value of the measured heat transfer amount is 3 W or less. Diapers. A liquid-retaining absorbent body, a surface sheet disposed on the skin facing surface side of the absorbent body, and an intermediate layer disposed between the absorbent body and the surface sheet,
The surface sheet is composed of a joined body of an upper layer fiber sheet and a lower layer fiber sheet, and has a plurality of convex portions composed of the upper layer fiber sheet on the substantially flat lower layer fiber sheet by three-dimensional shaping of the upper layer fiber sheet. And a concave-convex shaped composite sheet having a concave portion between the convex portions, wherein the concave portion and the convex portion in the composite sheet are alternately arranged in one direction of the composite sheet and are orthogonal to the direction. The disposable diaper according to any one of claims 1 to 3, wherein the disposable diapers are alternately arranged.   The said intermediate | middle layer consists of the layer of the air through nonwoven fabric located in the said surface sheet side, and the layer of the spunlace nonwoven fabric located in the said absorber side, This spunlace nonwoven fabric contains rayon as a constituent fiber. Disposable diapers.   The disposable diaper according to claim 4, wherein the intermediate layer includes a non-woven fabric layer positioned on the top sheet side and a cross-linked fiber layer positioned on the absorber side. A liquid-retaining absorbent body, a surface sheet disposed on the skin facing surface side of the absorbent body, and an intermediate layer disposed between the absorbent body and the surface sheet,
The topsheet has a first fiber layer on the skin facing side and a second fiber layer adjacent to the first fiber layer, and both layers are partially joined at a number of joints in a predetermined pattern and integrated in the thickness direction. The first fiber layer protrudes in a convex shape due to thermal contraction of the second fiber layer between the joints, and is made of a three-dimensional sheet in which a large number of irregularities are formed on the surface on the first fiber layer side. The disposable diaper in any one of claim | item 1 thru | or 3.   The said intermediate | middle layer consists of the layer of the air through nonwoven fabric located in the said surface sheet side, and the layer of the spunlace nonwoven fabric located in the said absorber side, This spunlace nonwoven fabric contains rayon as a constituent fiber. Disposable diapers.   The disposable diaper according to claim 7, wherein the intermediate layer includes a non-woven fabric layer positioned on the top sheet side and a crosslinked fiber layer positioned on the absorber side.

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