JP5386341B2 - Disposable diapers - Google Patents

Description

  The present invention relates to an improvement of a disposable diaper provided with a fastening tape.

  In the disposable diaper provided with the fastening tape formed using the male material of the mechanical tape, the present applicant has previously applied the embossing treatment to the raw nonwoven fabric, and the engaging portion that engages the fastening tape, The thing which the elongation rate at the time of 2N / 25mm load of CD direction is 75% or less of this raw fabric nonwoven fabric was proposed (refer patent document 1). This disposable diaper has the advantage that the engaging force between the male material of the mechanical tape and the engaging portion is increased, and the fluff is small. Furthermore, there is an advantage that the fit of the diaper is excellent without being impaired.

Apart from this diaper, the engagement portion is made of an air-through nonwoven fabric in which high-temperature air is blown onto a web made of a large number of heat-fusible short fibers so that the fibers are entangled with each other at high density. The disposable diaper which becomes is also known (refer patent document 2). This nonwoven fabric has a basis weight of 17 to 50 g / m ² , and the short fiber fineness of the nonwoven fabric is 0.5 to 8 denier. According to this diaper, it is described in the same document that the peeling strength between the male member and the engaging portion of the fastening tape is increased and the decrease in the peeling strength after repeated fastening and attachment is suppressed.

  In recent years, touches such as underwear have been emphasized in disposable diapers, and it has become the mainstream to employ a non-woven fabric that is comfortable to the back sheet. Moreover, as a fastening system, as referred to in Patent Documents 1 and 2, a male material of a mechanical tape is used as a fastening tape, and a large number of fibers are looped or arched on a base tape as an adherent member. It has been proposed to use a non-woven fabric having a good texture from a slightly hard knitted fabric. However, in Patent Documents 1 and 2, in order to increase the engagement force, the touch as a non-woven fabric cannot be said to be good, such as increasing the strength of the non-woven fabric or using a fiber having a large fineness. When the nonwoven fabrics of Patent Documents 1 and 2 are used as the back sheet of the disposable diaper, there are problems of poor touch and poor followability of movement due to hardness.

  Apart from the technology of disposable diapers, the present applicant has previously described a number of pressure-bonding parts in which constituent fibers are pressure-bonded or bonded with respect to a nonwoven fabric made of heat-extensible fibers, which are fibers whose length is increased by heating. In addition, the intersection of the constituent fibers is joined by means other than pressure bonding at a portion other than the pressure bonding portion, and the pressure bonding portion is a concave portion and the concave and convex shape is a convex portion between the concave portions. A three-dimensional shaped non-woven fabric having at least one surface was proposed (see Patent Document 3). This nonwoven fabric has the advantage that it has a three-dimensional uneven shape, is flexible, and has a low basis weight, without using a special manufacturing method, by using heat-extensible fibers as a raw material. This nonwoven fabric is suitably used as a surface sheet, a second sheet (a sheet disposed between the surface sheet and the absorber), a back sheet, a leak-proof sheet, etc. in the field of disposable hygiene articles such as disposable diapers and sanitary napkins. It is done.

JP 11-335960 A JP 2003-180748 A JP 2005-350836 A

  An object of the present invention is to use a nonwoven fabric, which is an adherent member, in a disposable diaper provided with a fastening tape, which has a high engagement force with a hook member of a hook-and-loop fastener, good touch, small fluffing, and excellent productivity. It is to provide a disposable diaper that is comfortable to touch.

The present invention comprises a top sheet positioned on the skin facing surface side of the wearer, a back sheet positioned on the non-skin facing surface side, and an absorber interposed between both sheets, and is substantially vertically long. A disposable diaper provided with a fastening tape extending laterally from the left and right side edges at one end in the longitudinal direction,
The fastening portion of the fastening tape is formed of a hook member of a hook-and-loop fastener, and a coating portion made of a nonwoven fabric that engages with the fastening portion is provided on the surface of the back sheet.
The nonwoven fabric includes a heat-extensible fiber whose length is extended by heating, and has a plurality of convex portions and concave portions on one surface side, and the heat-extensible fiber constituting the convex portion has a thermal elongation rate. However, the lower part is higher than the upper part of the convex part,
As the raw fiber of the heat-extensible fiber, two kinds of heat-extensible raw fibers having different temperatures at which thermal extension is started are used.
The upper side of the convex part is formed using a low-temperature heat-extensible raw fiber that starts thermal elongation at a relatively low temperature, and the lower part of the convex part is a high-temperature heat-extensible raw fiber that starts thermal extension at a relatively high temperature. The disposable diaper currently formed using is provided.

Moreover, this invention is equipped with the surface sheet located in a wearer's skin opposing surface side, the back surface sheet located in the non-skin opposing surface side, and the absorber interposed between both sheets, and is a substantially vertically long shape. Disposable diapers,
A non-woven fabric is disposed on the outer surface of the back sheet, the non-woven fabric includes a heat-extensible fiber whose length is extended by heating, and has a plurality of convex portions and concave portions on one surface side. The thermal stretchable fiber constituting the thermal elongation rate is higher in the lower part than in the upper part of the convex part,
As the raw fiber of the heat-extensible fiber, two kinds of heat-extensible raw fibers having different temperatures at which thermal extension is started are used.
The upper side of the convex part is formed using a low-temperature heat-extensible raw fiber that starts thermal elongation at a relatively low temperature, and the lower part of the convex part is a high-temperature heat-extensible raw fiber that starts thermal extension at a relatively high temperature. The disposable diaper currently formed using is provided.

  According to the disposable diaper of the present invention, the engagement force between the fastening portion in the fastening tape and the adherend portion that engages with the fastening portion is increased. Moreover, even if it repeats and peels off, it becomes difficult to fluff in a to-be-adhered part, and there is little fall of engagement force. Furthermore, the touch of the adherend is good and the texture is excellent.

Drawing 1 is a perspective view showing the wearing state of one embodiment of the disposable diaper of the present invention. FIG. 2 is a perspective view showing a state in which the diaper shown in FIG. 1 is developed. 3 is a cross-sectional view taken along line III-III in FIG. Fig.4 (a) is a perspective view which shows the nonwoven fabric used for the diaper shown in FIG. 1, FIG.4 (b) is a principal part enlarged view of the longitudinal cross-section of the nonwoven fabric shown to Fig.4 (a). FIG. 5 is a schematic view showing an apparatus suitably used for manufacturing the nonwoven fabric shown in FIG.

  The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 shows a mounted state of an embodiment of the disposable diaper of the present invention. 2 is a state in which the diaper shown in FIG. 1 is developed, and FIG. 3 is a cross-sectional view taken along line III-III in FIG.

  The diaper 100 shown in FIGS. 1 to 3 is of a so-called unfolded type (tape-clamping type). The diaper 100 has a top sheet 111 located on the side close to the wearer's skin, a back sheet 112 located on the side far from the wearer's skin, and an absorbent body 113 disposed between both sheets 111, 112. doing. The diaper 100 in the unfolded state has a substantially vertically long shape. The diaper 100 has a dorsal region A on one end side in the longitudinal direction and a ventral region C on the other end side. Further, a crotch region B is provided between the dorsal region A and the ventral region C.

  The absorbent body 113 extends from the back region A to the ventral region C of the diaper 100. The absorber 113 is sandwiched and fixed by the top sheet 111 and the back sheet 112. The top sheet 111 and the back sheet 112 extend from the front and rear end edges of the absorbent body 113 in the front-rear direction to form waist flaps 114 and 114, respectively. Further, the top sheet 111 and the back sheet 112 extend in the horizontal direction from the left and right side edges of the absorber 113 to form leg flaps 115 and 115.

  The leg flap 115 is provided with leg elastic strands 117 for allowing the diaper wearer to fit the diaper 100 around the legs of the wearer. The leg elastic strands 117 are disposed on both left and right sides of the diaper 100 and extend in the longitudinal direction of the diaper 100. One end of the leg elastic strand 117 terminates in the vicinity of the boundary between the back region A and the crotch region B of the diaper 100. The other end of the leg elastic strand 117 is terminated near the boundary between the ventral region C and the crotch region B of the diaper 100. However, in some cases, the ends of the leg elastic strands 117 may be located in the dorsal region A and / or ventral region C. Due to the contraction of the leg elastic strands 117, a gather is formed in the leg flap 115.

  A pair of three-dimensional guard forming sheets 116 are arranged on both the left and right sides of the diaper 100 on the surface sheet side, and a three-dimensional guard 118 is formed. A three-dimensional guard elastic member 119 is disposed at the free end of the three-dimensional guard 118 to form a gather. The leg elastic strands 117 described above are stretched and sandwiched and fixed by the three-dimensional guard forming sheet 116 and the back sheet 112.

  A pair of fastening tapes 120 and 120 are attached to the left and right sides of the waist flap 114 in the back region A of the diaper 100. A fastening means 120 a for fastening the fastening tape 120 to the back sheet 112 is provided on the front surface of the fastening tape 120, that is, the surface of the diaper 100 on the same side as the top sheet 111. For example, a hook member of a hook-and-loop fastener is used as the fixing means 120a.

  A waist elastic strand 121 extending in the width direction of the diaper 100 is disposed in an extended state between the fastening tapes 120 and 120 of the waist flap 114 in the back region A of the diaper 100. Similarly, waist elastic strands 121 extending in the width direction of the diaper 100 are also arranged in an extended state on the waist flap 114 in the ventral region BC of the diaper 100. The waist elastic strand 121 is sandwiched and fixed between the top sheet 111 and the back sheet 112. As the waist elastic strands 121 contract, a gather is formed in the waist flap 114.

  As a constituent material of each member which comprises the diaper 100, the thing similar to what was conventionally used for this kind of diaper can be used. For example, as the top sheet 111, liquid permeable sheet materials such as various nonwoven fabrics can be used. When the constituent fibers of the nonwoven fabric are hydrophobic, the nonwoven fabric can be subjected to a hydrophilic treatment. As the back sheet 112, a liquid-impermeable or hardly-permeable sheet material such as a sheet made of various synthetic resins, a spunbond-meltblown-spunbond laminated nonwoven fabric, or the like can be used. In addition to being liquid impermeable or hardly permeable, this sheet is preferably moisture permeable. As the absorbent body 113, for example, a laminate of fluff pulp and superabsorbent polymer particles wrapped with tissue paper or the like can be used. As the three-dimensional guard forming sheet 116, a water-repellent nonwoven fabric or the like can be used.

  As shown in FIG. 3, the nonwoven fabric 10 is disposed on the surface of the back sheet 112. The back sheet 112 and the nonwoven fabric 10 are bonded together by means such as intermittent application of a hot melt adhesive. The nonwoven fabric 10 is distribute | arranged to the whole region of the back surface sheet 12, and comprises the outer surface of the diaper 100. At the same time, the nonwoven fabric 10 also has a function as an adherent portion that engages with a hook member of a hook-and-loop fastener that is the fastening means 120a in the fastening tape 120 described above. The diaper of this invention has one of the characteristics in this nonwoven fabric.

  FIG. 4A shows a perspective view of the nonwoven fabric 10. Moreover, the principal part enlarged view of the longitudinal cross-section of the nonwoven fabric 10 shown to Fig.4 (a) is shown by FIG.4 (b). The nonwoven fabric 10 has a multilayer structure. One side of the nonwoven fabric 10 (the back surface 10b in FIG. 4A) is substantially flat, and the other surface (the front surface 10a in FIG. 4A) has a concavo-convex shape having a large number of convex portions 19 and concave portions 18. ing. That is, it is three-dimensionally shaped. The back surface 10 b is a surface facing the back sheet 112, and the front surface 10 a is a surface constituting the outer surface of the diaper 100. The concave portion 18 includes a joint portion formed by compacting and joining the constituent fibers of the nonwoven fabric 10. Examples of means for forming the joint include embossing with or without heat, ultrasonic embossing, and the like. On the other hand, the convex part 19 is a non-joining part. The thickness of the concave portion 18 is smaller than the thickness of the convex portion 19. The convex portion 19 has a shape protruding toward the surface side of the nonwoven fabric 10 (upper surface side in FIG. 4B). The inside of the convex portion 19 is filled with the constituent fibers of the nonwoven fabric 10. In the convex part 19, the heat | fever extensible fibers which are the constituent fibers of the nonwoven fabric 10 are fuse | melted in those intersections. Since the heat-extensible fibers are thermally bonded to each other at the convex portion 19, fuzz on the surface of the nonwoven fabric 10 is less likely to occur. Whether or not the fibers are thermally fused is determined by observing the nonwoven fabric 10 with a scanning electron microscope.

  The recessed part 18 has the 1st linear part 18a extended in one direction in parallel with each other. Moreover, the recessed part 18 has the 2nd linear part 18b extended in one direction in parallel so that it may cross | intersect a 1st linear part. A closed rhombus is formed by intersecting the two linear portions 18a and 18b. This rhombus portion is a convex portion 19. That is, the convex portion 19 is formed to be surrounded by a continuous closed concave portion 18.

  The area ratio between the concave portion 18 and the convex portion 19 in the nonwoven fabric 10 is represented by an embossing rate (an embossed area ratio, that is, a ratio of the total area of the concave portion 18 with respect to the entire nonwoven fabric 10). It affects the engagement force with the fastener and the fuzziness. From these viewpoints, the embossing rate in the nonwoven fabric 10 is preferably 5 to 35%, particularly preferably 10 to 25%. This embossing rate is measured by the following method. First, an enlarged photograph of the surface of the nonwoven fabric 10 is obtained using a microscope (manufactured by Keyence Corporation, VHX-900), the scale is aligned with the enlarged photograph of the nonwoven fabric surface, and the dimension of the recess 18 (that is, the embossed portion) is measured. The total area P of the recesses 18 in the entire area Q of the measurement site is calculated. The embossing rate can be calculated by the formula (P / Q) × 100.

  The nonwoven fabric 10 includes, as its constituent fibers, heat-extensible fibers that are fibers whose length is increased by heating. The nonwoven fabric 10 here is a nonwoven fabric in a state of being incorporated in the diaper 100. That is, the non-woven fabric 10 is in a state after being incorporated in the diaper 100, and its constituent fibers have a heat stretchability. Moreover, the nonwoven fabric 10 has the heat | fever extensibility also in the state before integrating in the diaper 100 (namely, the state of a raw fabric nonwoven fabric). As the heat-extensible fiber, for example, a fiber in which the crystal state of the resin is changed by heating and stretched can be mentioned. The nonwoven fabric 10 manufactured using the heat-extensible fiber becomes bulky or exhibits a three-dimensional appearance due to the thermal expansion of the fiber due to heat treatment in the manufacturing process of the nonwoven fabric 10. Moreover, the heat-extensible fiber exists in the nonwoven fabric 10 in a state that can be extended by heating. Therefore, by heating the nonwoven fabric 10 before being bonded to the back sheet 112, the heat-extensible fibers contained therein are stretched, and the nonwoven fabric 10 is more bulky than before the heating, and the adherend portion And the function as the outer layer material of the diaper 100 are enhanced. Specifically, the inter-fiber distance is increased, and the advantageous effect that the hook member of the hook-and-loop fastener can easily enter between the fibers is achieved. As a result, the engagement force between the fastening tape 120 and the nonwoven fabric 10 is increased. Moreover, the texture of the nonwoven fabric 10 increases due to the bulkiness. Details of the heat-extensible fibers will be described later.

  The heat-extensible fiber particularly preferably used in the nonwoven fabric 10 includes a first resin component made of a high melting point resin and a melting point lower than the melting point of the first resin component (in the case of a resin having no melting point described later, a softening point). And a second resin component made of a low-melting-point resin having a substitute, and the second resin component is a composite fiber in which at least a part of the fiber surface is continuously present in the length direction (hereinafter, this fiber is referred to as “ It is referred to as “heat-extensible composite fiber”. The 1st resin component in a heat | fever extensible composite fiber is a component which expresses the heat | fever extensibility of this fiber, and a 2nd resin component is a component which expresses heat-fusibility. Details of the heat-extensible composite fiber will be described later.

  In each convex part 19 of the nonwoven fabric 10, there is a difference in the thermal elongation rate between the heat-extensible fibers located in the upper part 19a of the convex part 19 and the heat-extensible fibers located in the lower part 19b. The nonwoven fabric 10 has one of the features in this respect. This feature is satisfied both in the state in which the nonwoven fabric 10 is incorporated in the diaper 100 and in the state before the nonwoven fabric 10 is incorporated in the diaper 100 (that is, the state of the raw nonwoven fabric).

  In the nonwoven fabric 10, when compared at the same heating temperature, the heat-extensible fibers constituting the convex portion 19 are those located in the lower portion 19 b rather than those located in the upper portion 19 a of the convex portion 19. Is relatively high. That is, when heat at a certain temperature is applied, the fiber located at the lower portion 19b of the convex portion 10 has a greater degree of thermal expansion than the fiber located at the upper portion 19a. In other words, the fiber located in the upper part 19a of the convex portion 10 has a smaller degree of thermal expansion than the fiber located in the lower part 19b. Since the degree of thermal expansion of the heat-extensible fibers contained in the convex portion 19 is such, the nonwoven fabric 10 is not easily stretched by the fibers located in the upper portion 19a. Before being combined, when the function of the nonwoven fabric 10 as an adherent part and the function of the outer layer material of the diaper 10 is enhanced by processing for bulk recovery such as blowing hot air, the surface of the upper part 19a is less likely to fluff. An advantageous effect is obtained. This is particularly advantageous when the fastening tape 120 is repeatedly applied to and peeled from the nonwoven fabric 10. As a result, there is an advantageous effect that there is little decrease in engagement force even when repeated peeling is performed. On the other hand, since the fiber located in the lower part 19b is easily stretched by heat, when the nonwoven fabric 10 is subjected to processing for bulk recovery such as blowing hot air to enhance the function of the nonwoven fabric 10 as an adherend, the lower part 19b The side fibers are thermally stretched, the bulk recoverability is improved, the interfiber distance is increased, and the hook member of the hook-and-loop fastener can easily enter between the fibers. As a result, the engagement force between the fastening tape 120 and the nonwoven fabric 10 is increased. Bulk recovery by blowing hot air onto the nonwoven fabric 10 will be described later.

  As a result of the examination by the present inventors, it was found that the heat-extensible fiber has a lower Young's modulus than a fiber made of a normal fiber-forming resin (a fiber that does not thermally stretch or heat shrinks). Accordingly, when the fastening tape 120 is peeled off while the nonwoven fabric 10 and the hook member of the hook-and-loop fastener that is the fastening portion 120a of the fastening tape 120 are engaged, the constituent fibers of the nonwoven fabric 10 are easily plastically deformed. As a result, the breakage of the bonding points between the fibers is effectively prevented. This also makes it difficult for the non-woven fabric 10 to be fuzzed, and the decrease in the engagement force is reduced even after repeated peeling. The prevention of breakage of the bonding points between the fibers means that it is not necessary to increase the bonding strength of the bonding points. This contributes to the improvement of the texture of the nonwoven fabric 10. Furthermore, a low Young's modulus of the fiber means that the fiber itself is soft. The softness of the fibers also contributes to the improvement of the touch of the nonwoven fabric 10 and brings a good texture to the nonwoven fabric 10. Further, in the nonwoven fabric 10, it is more preferable in terms of prevention of fluffing and texture that the fiber 19 has a lower Young's modulus on the upper portion 19 a side of the convex portion 19 than on the lower portion 19 b side of the convex portion 19.

From the above viewpoint, it is preferable that the heat-extensible fiber contained in the nonwoven fabric 10 has a Young's modulus of 0.2 to 1 GPa, particularly 0.4 to 0.8 GPa. In order to set the Young's modulus within this range, the stretching conditions for producing the heat-extensible fibers (lowering the draw ratio), the type of resin constituting the heat-extensible fibers, the amount of resin blended (two-component system) In the case of fibers) etc. may be adjusted appropriately. Young's modulus is measured by the following method.
[Young's modulus measurement method]
A thermomechanical analyzer TMA / SS6000 manufactured by Seiko Instruments Inc. is used. The measurement environment temperature is 25 ° C. As a sample, after preparing a plurality of fibers having a fiber length of 10 mm or more so that the total weight per 10 mm of the fiber length is 0.5 mg, and arranging the plurality of fibers in parallel, The chuck is mounted at a distance of 10 mm, and a constant load of 0.73 mN / dtex is applied. Then, after obtaining a stress-strain curve under the condition of 240 mN / min, the slope of the tangent of the curve when the strain is 0.1% is defined as the Young's modulus.

  The thermal elongation rate of the heat-extensible fibers contained in the convex portion 19 may be gradually increased from the upper portion 19a toward the lower portion 19b, or may be increased in a step shape. In the present invention, there is no clear boundary between the upper part 19 a and the lower part 19 b of the convex part 19, and the “upper part 19 a” and “lower part 19 b” in the thickness direction of the nonwoven fabric 10 are relative to each other in the convex part 19. This indicates a general positional relationship.

  From the viewpoint of making the above effect even more remarkable, at the melting point + 20 ° C. of the low melting point resin constituting the heat-extensible fiber located above the convex portion (in the case of a resin having no melting point, the temperature of the softening point + 20 ° C. The thermal elongation rate of the heat-extensible fibers located on the upper portion 19a of the convex portion 19 is 0.1% or more and less than 3.0%, particularly 0.1% or more and less than 2.5%, especially 0.5 % Or more and less than 2.5%. On the other hand, the thermal elongation rate of the heat-extensible fiber located at the lower portion 19b of the convex portion 19 is 3.0% or more and less than 20%, particularly 3.5% or more and less than 10.5%, especially at the above temperature. It is preferable that it is 4.0% or more and less than 10%. This thermal elongation rate is measured for the heat-extensible fibers contained in the convex portion 19. A method for measuring the thermal elongation rate will be described later.

  The melting points of the first resin component and the second resin component are measured using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.). A finely cut fiber sample (sample weight 2 mg) is subjected to thermal analysis at a heating rate of 10 ° C./min, and the melting peak temperature of each resin is measured. The melting point is defined by its melting peak temperature. When the melting point of the second resin component cannot be clearly measured by this method, this resin is defined as “resin having no melting point”. In this case, the temperature at which the second resin component is fused to such an extent that the fusion point strength of the fiber can be measured is defined as the temperature at which the molecular flow of the second resin component begins.

  As a fiber used as the raw material of the nonwoven fabric 10, a heat-extensible fiber is used. In the following description, for the purpose of distinguishing between the heat-extensible fibers contained in the nonwoven fabric 10 and the heat-extensible fibers that are the raw material of the nonwoven fabric 10, the heat-extensible fibers that are the raw material of the nonwoven fabric 10 are referred to as “ It is called “heat-extensible raw fiber”. When simply referred to as “heat-extensible fiber”, it refers to a heat-extensible fiber contained in the nonwoven fabric 10. As the heat-extensible raw fiber, it is preferable to use two kinds of fibers having different temperatures at which the heat elongation starts. In other words. Heat-extensible raw fiber that starts thermal elongation at a relatively low temperature (hereinafter referred to as “low-temperature heat-extensible raw fiber”) and heat-extensible raw fiber that starts thermal elongation at a relatively high temperature (hereinafter referred to as “ It is preferable to use "high temperature heat-extensible raw fiber". In the nonwoven fabric 10 manufactured using such two kinds of fibers, the upper portion 19a side of the convex portion 19 is formed using a low-temperature heat-extensible raw fiber, and the lower portion 19b side of the convex portion 19 is a high-temperature heat-extensible raw material fiber. It is preferable that it is formed using. The preferable manufacturing method of the nonwoven fabric 10 using a heat | fever extensible raw fiber is mentioned later.

  When using the two types of heat-extensible raw fiber described above, the blending ratio (weight) of both is preferably low-temperature heat-extensible raw fiber: high-temperature heat-extensible raw fiber = 95: 5 to 5:95, 80:20 to 20:80 is more preferable, 60:40 to 40:60 is still more preferable, and 55:45 to 45:55 is still more preferable.

  The heat-extensible raw fiber (low-temperature heat-extensible raw fiber and high-temperature heat-extensible raw fiber) particularly preferably used in the nonwoven fabric 10 includes a first resin component made of a high-melting resin and a melting point lower than the melting point of the first resin component. Or a second fiber component composed of a low-melting point resin having a softening point, and the second resin component is continuously present in the length direction on at least a part of the fiber surface (hereinafter, this fiber is referred to as “ It is referred to as “heat-extensible composite raw fiber”. The 1st resin component in a heat | fever extensible composite raw material fiber is a component which expresses the heat | fever extensibility of this fiber, and a 2nd resin component is a component which expresses heat-fusibility.

  The heat-extensible composite raw fiber can be stretched by heat at a temperature lower than the melting point of the first resin component. The heat-stretchable composite raw fiber has a temperature that is 10 ° C higher than the melting point of the second resin component, and in the case of a resin that does not have a melting point, the thermal elongation rate at a temperature 10 ° C higher than the softening point is 0.5 to 20%, It is preferably 3 to 20%, particularly 5 to 20%. The nonwoven fabric 10 manufactured using such a fiber having a thermal elongation rate as a raw material becomes bulky or exhibits a three-dimensional appearance due to thermal expansion of the fiber in the manufacturing process of the nonwoven fabric 10. For example, the uneven shape on the surface of the nonwoven fabric 10 becomes remarkable.

The thermal elongation rate of the raw fiber is measured by the following method. A thermomechanical analyzer TMA / SS6000 manufactured by Seiko Instruments Inc. is used. As a sample, after preparing a plurality of fibers having a fiber length of 10 mm or more so that the total weight per 10 mm of the fiber length is 0.5 mg, and arranging the plurality of fibers in parallel, The chuck is mounted at a distance of 10 mm, the measurement start temperature is 25 ° C., and the temperature is increased at a temperature increase rate of 5 ° C./min with a constant load of 0.73 mN / dtex applied. The amount of elongation of the fiber at that time is measured, and in the case of a resin having no melting point at a temperature 10 ° C. higher than the melting point of the second resin component, the elongation amount Xmm at a temperature 10 ° C. higher than the softening point is read.
The thermal elongation rate of the raw fiber is calculated from (X / 10) × 100 [%].
In addition, the temperature at which the thermal expansion of the raw fiber starts is set to a temperature at which the thermal expansion rate of the raw fiber calculated by the above equation becomes 1%.
The reason why the thermal elongation rate is measured at the above-mentioned temperature is that, as will be described later, when the nonwoven fabric 10 is produced by thermally fusing the intersections of the fibers, they are above the melting point or softening point of the second resin component. It is because it is normal to manufacture in the range up to about 10 degreeC higher temperature.

  There is no restriction | limiting in particular in the kind of 1st resin component and 2nd resin component, What is necessary is just resin with fiber formation ability. In particular, the difference in melting point between the two resin components, or the difference between the melting point of the first resin component and the softening point of the second resin component is 20 ° C. or more, particularly 25 ° C. or more. It is preferable because it can be easily performed. When the heat-extensible composite raw fiber is a core-sheath type, a resin having a melting point of the core component higher than the melting point or softening point of the sheath component is used. In particular, it is preferable to use a core-sheath type heat-extensible composite raw material fiber having polypropylene (PP) or polyethylene terephthalate (PET) as a core and a resin having a melting point lower than these as a sheath. As a preferable combination of the first resin component and the second resin component, as the second resin component when the first resin component is PP, the high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear Examples thereof include polyethylene (PE) such as low density polyethylene (LLDPE), ethylene propylene copolymer, and polystyrene. In addition, when a polyester resin such as PET or polybutylene terephthalate (PBT) is used as the first resin component, in addition to the example of the second resin component described above, PP, copolymer polyester, etc. may be used as the second resin component. Can be mentioned. Furthermore, examples of the first resin component include polyamide-based polymers and two or more types of copolymers of the first resin component described above, and examples of the second resin component include two or more types of the second resin component described above. Copolymers are also included. These are appropriately combined.

  In particular, the upper portion 19a side of the convex portion 19 of the nonwoven fabric 10 includes a core-sheath type heat-extensible conjugate fiber whose core is polypropylene and the sheath is polyethylene, and the lower portion 19b side of the convex portion 19 is a polyethylene terephthalate core and the sheath. It is possible to effectively prevent fluffing on the surface 10a when hot air is blown to the nonwoven fabric 10 and to make the bulk recovery of the nonwoven fabric 10 more remarkable by including the core-sheath type thermally stretchable conjugate fiber whose polyethylene is polyethylene To preferred.

  As the fiber length of the heat-extensible raw material fiber, an appropriate length is used according to the method for manufacturing the nonwoven fabric 10. For example, when the nonwoven fabric 10 is manufactured by a card method as described later, the fiber length is preferably about 30 to 70 mm.

  The fiber diameter of the heat-extensible raw fiber is reduced by heat extension. Therefore, the heat-extensible fiber contained in the nonwoven fabric 10 generally has a fiber diameter smaller than the fiber diameter of the heat-extensible raw material fiber that is the raw material. The fiber diameter of the heat-extensible fiber contained in the nonwoven fabric 10 is appropriately selected according to the specific use of the nonwoven fabric 10. When the nonwoven fabric 10 is used as a constituent member of an absorbent article such as a surface sheet of the absorbent article, the fiber diameter of the heat-extensible fibers contained in the nonwoven fabric 10 is 10 to 35 μm, particularly 15 to 30 μm, especially 15 to 25 μm. It is preferable that The fiber diameter of the heat-extensible raw fiber is determined in consideration of the fiber diameter of the heat-extensible fiber contained in the nonwoven fabric 10.

  Examples of the heat-extensible raw fiber include Japanese Patent No. 4131852, Japanese Patent Application Laid-Open No. 2005-350836, Japanese Patent Application Laid-Open No. 2007-303035, Japanese Patent Application Laid-Open No. 2007-204899, Japanese Patent Application Laid-Open No. 2007-204901, and Japanese Patent Application Laid-Open No. 2007. -204902, Unexamined-Japanese-Patent No. 2008-101285, etc. can use the fiber.

  The non-woven fabric 10 may be composed only of heat-extensible fibers, or contains other fibers, for example, two components having different melting points, in addition to the heat-extensible fibers, and is a non-heat-extensible core formed by stretching. The sheath-type heat-fusible conjugate fiber may be included. In addition, fibers that do not inherently have heat-fusibility (for example, natural fibers such as cotton and pulp, rayon, and acetate fibers) may additionally be included. When the nonwoven fabric 10 includes other fibers in addition to the heat-extensible fibers, the proportion of the heat-extensible fibers in the nonwoven fabric 10 is preferably 30% by weight or more, particularly preferably 50% by weight or more. The fiber ratio is preferably 70% by weight or less, particularly preferably 50% by weight or less.

The nonwoven fabric 10 preferably has a basis weight of 10 to 80 g / m ² , particularly 15 to 60 g / m ² . The thickness of the convex portion 19 in the nonwoven fabric 10 is preferably 0.5 to 3.0 mm, particularly preferably 0.7 to 3.0 mm, after bulk recovery by hot air (this will be described later). On the other hand, the thickness of the recess 18 is preferably 0.01 to 0.4 mm, particularly preferably 0.02 to 0.2 mm. The thickness of the concave portion 18 is not substantially changed before and after the bulk recovery by hot air. The measuring method of the thickness of the convex part 19 and the recessed part 18 is as follows. It is measured by observing the longitudinal section of the nonwoven fabric 10. First, the nonwoven fabric 10 is cut into a size of 100 mm × 100 mm, and a measurement piece is collected. A plate of 12.5 g (diameter 56.4 mm) is placed on the measurement piece, and a load of 49 Pa is applied. The longitudinal cross section of the nonwoven fabric 10 in this state is observed with a microscope (VHX-900, manufactured by Keyence Corporation), and the thicknesses of the convex portions 19 and the concave portions 18 are measured. Let the thickness of this convex part 19 be the thickness of the nonwoven fabric 10.

  Next, the suitable manufacturing method of the nonwoven fabric 10 is demonstrated, referring FIG. The apparatus 20 shown in FIG. 5 includes a web manufacturing unit 30, an embossing unit 40, and a hot air blowing unit 50. In the web manufacturing unit 30, the web 10a is manufactured using heat-extensible raw fiber. As the heat-extensible raw fiber, a two-component composite fiber including the first resin component and the second resin component described above is used.

  As the web manufacturing unit 30, for example, two card machines 31a and 31b as shown in the figure can be used. Depending on the specific application of the nonwoven fabric 10, another web manufacturing apparatus such as an airlaid apparatus can be used instead of the card machine. The card machine 31a is supplied with a low-temperature heat-extensible raw fiber. The card machine 31b is supplied with high-temperature heat-extensible raw fiber. The webs formed by the respective card machines are laminated to form a web 10a. In the web 10a, the low-temperature heat-extensible raw fiber is located in the upper layer, and the high-temperature heat-extensible raw fiber is located in the lower layer. In the following description, in the web 10a, the surface on the side where the low-temperature heat-extensible raw fiber is present is referred to as the first surface 101, and the surface on the side where the high-temperature heat-extensible raw fiber is present is referred to as the second surface 102. I will call it. The first surface 101 is a surface that comes into contact with the pattern roll 41 in the embossing unit 40 to be described later, and is a surface to which hot air is blown in the hot air blowing unit 50. The 2nd surface 102 is a surface which contacts the flat roll 42 in the embossing part 40, and is a surface which opposes the conveyor belt 52 which consists of a breathable net in the hot air spraying part 50 mentioned later.

  The web 10a manufactured in the web manufacturing unit 30 is in a state where its constituent fibers are loosely entangled with each other, and the shape retention as a sheet is not achieved. Therefore, in order to impart shape retention as a sheet to the web 10a, the web 10a is processed in the embossing section 40 to form the embossed web 10b.

  The embossing part 40 is provided with a pair of rolls 41 and 42 arranged to face each other with the web 10a interposed therebetween. The roll 41 is made of a metal pattern roll having a large number of irregularities formed on its peripheral surface. The uneven pattern in the pattern roll can be appropriately selected according to the specific use of the nonwoven fabric 10. For example, in the case of forming the rhomboid emboss pattern shown in FIG. 4, convex portions having a shape corresponding to the rhombus lattice may be formed on the peripheral surface of the roll 41. In addition, when it is desired to form a dot-like emboss pattern (not shown) on the nonwoven fabric 10, a convex portion having a shape corresponding to the dot may be formed on the peripheral surface of the roll 41. On the other hand, the roll 42 is a flat roll having a smooth peripheral surface. The roll 42 is made of metal, rubber, paper, or the like.

  In the embossing part 40, the web 10a is pinched by both rolls 41 and 42 to perform embossing. Specifically, the heat-extensible fibers, which are constituent fibers of the web 10a, are consolidated by consolidation with or without heat to form joints composed of a large number of embossed portions on the web 10a. 10b is manufactured. In this manufacturing method, the roll 41 and the roll 42 have a heatable structure. During the operation of the embossing section 40, it is preferable that the pattern roll 41 and / or the flat roll 42 are heated to a predetermined temperature.

  When at least one of the pattern roll 41 and the flat roll 42 is heated in the embossed portion 40, the heating temperature is the melting point of the second resin component in the low-temperature heat-extensible raw fiber −20 ° C. or higher and the first resin component The temperature is preferably lower than the melting point.

  The embossed web 10 b to which shape retention is imparted by the processing by the embossing unit 40 is then conveyed to the hot air blowing unit 50. The hot air blowing unit 50 includes a hood 51. The embossed web 10 b passes through the hood 51. Moreover, the hot air spraying part 50 is provided with the conveyor belt 52 which consists of a breathable net. The conveyor belt 52 circulates in the hood 51. The embossed web 10b is placed on the conveyor belt 52 and conveyed in the hot air blowing unit 50. The conveyor belt 52 is formed from a resin such as polyamide or polyester.

  In the hot air blowing unit 50, hot air is blown against the embossed web 10b by an air-through method. That is, the hot air blowing unit 50 is configured such that hot air heated to a predetermined temperature penetrates the embossed web 10b. The air-through process is performed at a temperature at which the heat-extensible raw fiber in the embossed web 10b is elongated by heating. And it is performed at the temperature at which the intersections of the free stretchable raw fiber existing in portions other than the embossed portion of the embossed web 10b are heat-sealed.

  The temperature of the hot air is a temperature at which both the low-temperature heat-extensible raw fiber and the high-temperature heat-extensible raw fiber are thermally extended. Further, the temperature is set such that the low-temperature heat-extensible raw fibers are fused and the high-temperature heat-extensible raw fibers are fused. Specifically, the temperature of the hot air is preferably not lower than the melting point of the second resin component of the low-temperature heat-extensible raw fiber + 5 ° C. and not higher than the melting point of the first resin component. In particular, the melting point of the second resin component + 10 ° C. or higher and the melting point of the first resin component−10 ° C. or lower are preferable from the viewpoint of strength and texture. By blowing hot air at this temperature, the low-temperature heat-extensible raw fiber and the high-temperature heat-extensible raw fiber are thermally extended. Since a part of the low-temperature heat-extensible raw fiber and the high-temperature heat-extensible raw fiber are fixed by the embossed portions, the portions that are thermally stretched are the portions between the embossed portions. And since the low-temperature heat-extensible raw material fiber and the high-temperature heat-extensible raw material fiber are partially fixed by the embossed portion, the elongation of the heat-extended fiber loses its place in the plane direction of the embossed web 10b. And move in the thickness direction of the embossed web 10b. Thereby, the convex part 19 is formed between embossed parts, and the nonwoven fabric 10 becomes bulky. Moreover, it comes to have the three-dimensional appearance in which many convex parts 19 were formed. Furthermore, the low-temperature heat-extensible raw material fiber and the high-temperature heat-extensible raw material fiber are joined to each other or to each other by fusion at the intersection.

  The blowing of hot air in the present production method is terminated before the heat-extensible raw fiber is completely heated. Thereby, the nonwoven fabric containing the heat | fever extensible fiber which can be extended | stretched by the subsequent heat processing process is obtained. This non-woven fabric is the non-woven fabric 10 intended in the present invention. Therefore, the nonwoven fabric 10 is manufactured using a heat | fever extensible raw fiber, and contains a heat | fever extensible fiber.

  In hot air blowing, the degree of thermal elongation of the low-temperature heat-extensible raw fiber is larger than that of the high-temperature heat-extensible raw fiber by the lower temperature at which thermal elongation starts. As a result, when the heat treatment is further performed, the low-temperature heat-extensible raw fiber has a relatively low thermal elongation rate because the thermal elongation elongation is smaller. In other words, the high-temperature heat-extensible raw fiber has a relatively small degree of heat extension due to heat treatment. As a result, when the heat treatment is further performed, the high-temperature heat-extensible raw fiber has a relatively high thermal elongation rate because the thermal elongation elongation is larger. Moreover, since the high-temperature heat-extensible raw fiber is present at a position away from the first surface 101, which is the hot air blowing surface, the degree of thermal extension due to the hot air blowing is smaller than that of the low-temperature heat-extensible raw fiber, This also increases the degree of further thermal extension after thermal extension. For these reasons, in the obtained nonwoven fabric 10, the heat-extensible fiber constituting the convex portion 19 has a thermal elongation rate measured at the same temperature in the lower portion 19 b rather than the upper portion 19 a of the convex portion 19. Get higher.

  The nonwoven fabric 10 thus obtained is generally stored in a state wound in a roll shape. Due to this, the bulk of the nonwoven fabric 10 is often reduced. Therefore, when manufacturing the diaper 100 by sticking the nonwoven fabric 10 to the back sheet 112, hot air is blown onto the nonwoven fabric 10 by an air-through method. Thus, it is preferable to recover the reduced volume and enhance the function as the adherend of the nonwoven fabric 10 and the function of the diaper 10 as the outer layer material. In restoring the bulk, it is preferable to use hot air having a temperature lower than the melting point of the second resin component in the low-temperature heat-extensible raw fiber and at a temperature equal to or higher than the melting point −50 ° C. as the hot air blown to the nonwoven fabric 10. As a method for recovering the bulk of such a nonwoven fabric, for example, the techniques described in JP 2004-137655 A, JP 2007-177364 A, and JP 2008-231609 A related to the earlier application of the applicant of the present application are used. Can be used.

  The heat-extensible fibers contained in the nonwoven fabric 10 are stretched by the bulk recovery by blowing hot air. In this case, the heat-extensible fiber is not completely stretched by the blowing of hot air, and maintains the heat-extensible property even after the blowing of hot air. Therefore, after the bulk recovery, the heat-extensible fiber constituting the convex portion 19 in the nonwoven fabric 10 in a state of being bonded to the back sheet 112 has a thermal expansion rate that is lower in the lower portion than in the upper portion of the convex portion 19. It is in a high state.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, the concave portions of the nonwoven fabric 10 in the above embodiment have a rhombic lattice shape, but instead of this, dot-shaped concave portions that are dispersedly arranged in the form of dots may be employed. Moreover, you may employ | adopt the shape which makes a square or rectangular lattice shape, or a tortoiseshell pattern.

  Moreover, in the said embodiment, although hot embossing was used for formation of a junction part (concave part 18), it can replace with this and a junction part can also be formed by ultrasonic embossing. Moreover, the nonwoven fabric 10 is not restricted to the thing of a multilayer structure, A single layer structure may be sufficient. Furthermore, another nonwoven fabric may be further laminated on the back surface 10b side of the nonwoven fabric 10.

  Moreover, although the nonwoven fabric 10 of the said embodiment was uneven | corrugated on one surface of the two surfaces and the other surface was flat, it replaced with this and each surface is uneven | corrugated. May be.

  Moreover, in the said embodiment, although the surface 10a in the nonwoven fabric 10 comprised the outer surface of the diaper 100, and the back surface 10b was facing the back sheet 10, it replaces with this and the surface 10a of the nonwoven fabric 10 is facing the back sheet 10. You may let them.

  Moreover, in the said embodiment, although the nonwoven fabric 10 was distribute | arranged so that the whole region of the back surface sheet 112 might be covered, it replaces with this and the nonwoven fabric 10 is provided only in the position where the fastening part which consists of a hook member of a hook-and-loop fastener engages. It may be arranged.

  Moreover, in the said embodiment, although the nonwoven fabric 10 was used as an adhesion part with respect to the fastening part which consists of a hook member of a hook-and-loop fastener, it replaces with this and does not use the nonwoven fabric 10 as an adhesion part, but the outer surface of the diaper 100 You may use as a sheet | seat with the favorable texture which comprises.

  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.

[Example 1]
The multilayer nonwoven fabric 10 shown in FIG. 4 was manufactured using the apparatus shown in FIG. The pattern roll 41 in the apparatus shown in FIG. 5 had a rhombic lattice-shaped convex part with a line width of 0.8 mm. The embossing rate in this nonwoven fabric 10 was 23%. As a low-temperature heat-extensible raw fiber, a core-sheath type low-temperature heat-extensible raw fiber (fineness 4 dtex, thermal elongation rate 7. 9%) to produce a first card web having a basis weight of 20 g / m ² . Separately from this, as the high-temperature heat-extensible raw fiber shown in Table 1, a core-sheath type high-temperature heat-extensible raw fiber (4 dtex, A second card web having a basis weight of 20 g / m ² was produced using a thermal elongation of 8.3%. The first card web was stacked on the second card web, and this laminated web was supplied to the apparatus shown in FIG. 5 to produce a nonwoven fabric (basis weight 40 g / m ² ). The manufacturing conditions are as shown in Table 1. At this time, the laminated web was supplied to the apparatus shown in FIG. 5 so that irregularities were formed on the surface of the first card web and the surface of the second card web was flat. In the obtained nonwoven fabric, the intersections of the heat-extensible fibers were fused. The obtained nonwoven fabric was wound into a roll and stored.

Next, the disposable diaper shown in FIGS. 1 to 3 was manufactured. First, the nonwoven fabric was unwound from a roll, and bulk recovery and fiber elongation treatment were performed by blowing hot air by an air-through method. The hot air blowing conditions were a processing speed of 150 m / min, a hot air temperature of 115 ° C., a wind speed of 2.0 m / min, and a processing time of 0.3 seconds. Table 1 shows the thermal elongation rate, fineness, and thickness (under 49 Pa load) of the fibers in the nonwoven fabric after the hot air was blown. Next, the nonwoven fabric was bonded to a moisture permeable leakproof sheet (a stretched sheet mainly composed of polyethylene and calcium carbonate, basis weight 20 g / m ² ) as a back sheet of the diaper in the entire region. In bonding, the flat surface (back surface 10b in FIG. 4) of the nonwoven fabric was opposed to the back sheet. Moreover, the air through nonwoven fabric (basis weight 25g / m < ² >) by which the hydrophilic treatment was carried out was used as the surface sheet of a diaper. As the absorbent body, an absorbent body in which defibrated pulp and a superabsorbent resin were mixed and wrapped with a mount was used. As a fastening tape, a hook member (mushroom shape, hook density 256 pieces / cm ² , hook height 0.15 mm) of a hook-and-loop fastener is attached to a sheet based on a spunbond nonwoven fabric (basis weight 80 g / m ² ). Used. As other members, disposable diapers were obtained using materials known in the art.

[Comparative Example 1]
Instead of the nonwoven fabric used in Example 1, a nonwoven fabric was obtained in the same manner as in Example 1 except that the nonwoven fabric was produced by the following method using the fibers shown in Table 1, and a diaper was produced by the following method. A disposable diaper was obtained in the same manner as in Example 1.

A core-sheath type heat-fusible composite fiber (fineness: 9 dtex, thermal elongation: -1.0%) having a core of polypropylene and a sheath of low-melting-point polypropylene is used, and a first card web having a basis weight of 25 g / m ² is used. Manufactured. Separately, a core-sheath type heat-fusible composite fiber (fineness: 3.3 dtex, thermal elongation: -1.0%) having a core of polypropylene and a sheath of low melting point polypropylene is used, and a basis weight is 15 g / m ^2. A second card web was produced. The first card web was stacked on the second card web, and this laminated web was supplied to the apparatus shown in FIG. 5 to produce a nonwoven fabric. The manufacturing conditions are as shown in Table 1. At this time, the laminated web was supplied to the apparatus shown in FIG. 5 so that irregularities were formed on the surface of the first card web and the surface of the second card web was flat. The obtained nonwoven fabric was wound into a roll and stored. Thereafter, the nonwoven fabric was unwound from a roll, and bulk recovery and fiber elongation treatment were performed by blowing hot air by an air-through method. The hot air blowing conditions were the same as in Example 1. Table 1 shows the thermal elongation rate, fineness, and thickness (under 49 Pa load) of the fibers in the nonwoven fabric after the hot air was blown. Next, the nonwoven fabric was bonded to the same sheet as the back sheet used in Example 1. In bonding, the flat surface (back surface 10b in FIG. 4) of the nonwoven fabric was opposed to the back sheet. Except these, it carried out similarly to Example 1, and obtained the disposable diaper.

[Comparative Example 2]
Instead of the nonwoven fabric used in Example 1, a nonwoven fabric was obtained in the same manner as in Example 1 except that the nonwoven fabric was produced by the following method using the fibers shown in Table 1, and a diaper was produced by the following method. A disposable diaper was obtained in the same manner as in Example 1.
Non-woven fabric (basis weight 40 g / m) using the core-sheath type heat-fusible conjugate fiber (fineness 3.3 dtex, thermal elongation -0.5%) having a core of polypropylene and a sheath of polyethylene under the conditions shown in Table 1. ² ) got. The obtained nonwoven fabric was wound into a roll and stored. Thereafter, the nonwoven fabric was unwound from a roll, and bulk recovery and fiber elongation treatment were performed by blowing hot air by an air-through method. The hot air blowing conditions were the same as in Example 1. Table 1 shows the thermal elongation rate, fineness, and thickness (under 49 Pa load) of the fibers in the nonwoven fabric after the hot air was blown. Next, the nonwoven fabric was bonded to the same sheet as the back sheet used in Example 1. In bonding, the flat surface (back surface 10b in FIG. 4) of the nonwoven fabric was opposed to the back sheet. Except these, it carried out similarly to Example 1, and obtained the disposable diaper.

[Evaluation]
About the disposable diaper obtained by the Example and the comparative example, the peeling force (initial stage and after repetition) of a fastening tape and a diaper outer surface was measured with the following method. Moreover, the fuzz prevention property (initial stage and after repetition) of the diaper outer surface was evaluated by the following method. Furthermore, the touch of the outer surface of the diaper was evaluated by the following method. These results are shown in Table 1 below.

[The thermal elongation rate of the fiber at the convex portion of the nonwoven fabric]
The thermal expansion rate of the fiber in the convex part of the nonwoven fabric was measured and calculated in the following order 1-5.
1. Collection of fibers from nonwoven fabric Five fibers are collected from the upper and lower portions of the convex portion of the nonwoven fabric. The length of the fiber to be collected is 1 mm or more and 5 mm or less.
2. Measurement of the total length of the fiber collected from the nonwoven fabric The sampled fiber is sandwiched between the preparations, and the total length of the sandwiched fiber is measured. For measurement, a microscope VHX-900 and a lens VH-Z20R manufactured by KEYENCE were used. The measurement was performed by observing the fiber at a magnification of 50 to 100 times and using a measurement tool incorporated in the apparatus for the observed image. The length obtained by this measurement is defined as “the total length of fibers collected from the nonwoven fabric”.
3. Heat treatment of fibers collected from non-woven fabric Fibers collected from non-woven fabric whose total length was measured are put into a sample container for DSC6200 (product name: robot container 52-023P, 15 μL, made of aluminum) manufactured by SII Nano Technology Co., Ltd. The container containing the fibers is placed in a sample place in a heating furnace of DSC6200 that is set at 145 ° C. in advance. After the temperature (display name in the measurement software: sample temperature) measured with a thermocouple installed directly under the sample storage area of the DSC 6200 falls within the range of 145 ° C. ± 1 ° C., it is heated for 60 seconds and then quickly removed.
4). Measurement of the total length of the fiber after the heat treatment The fiber after the heat treatment is taken out from the DSC sample container and sandwiched between the preparations, and the total length of the sandwiched fiber is measured. For measurement, a microscope VHX-900 and a lens VH-Z20R manufactured by KEYENCE were used. The measurement was performed by observing the fiber at a magnification of 50 to 100 times and using a measurement tool incorporated in the apparatus for the observed image. The length obtained by this measurement is defined as “the total length of the fiber after the heat treatment”.
5. Calculation of thermal elongation rate (%) The thermal elongation rate (%) is calculated from the following equation.
Thermal elongation rate (%) = {(full length of fiber after heat treatment−full length of fiber collected from nonwoven fabric) ÷ (full length of fiber collected from nonwoven fabric)} × 100 [%]

[Peeling force between fastening tape and diaper outer surface (initial, after repeated)]
The fastening tape attached with the hook-and-loop fastener is cut from the produced disposable diaper, and is placed on the nonwoven fabric on the back sheet so that it is attached in the same manner as when the diaper is attached. At this time, the disposable diaper is placed flat on the work table in an expanded state with the back side as the top surface. Next, the surface fastener placed on the nonwoven fabric is reciprocated once by a 1 kg roller to press the surface fastener to the nonwoven fabric. The end of the fastener and the nonwoven fabric (disposable diaper) were grasped and pulled by a tensile tester, and the force required for the surface fastener to peel from the nonwoven fabric was measured. The tensile speed is 300 mm / min, n = 10, and the average value of the maximum points at that time is the initial peeling force.
The peeling force after repeated peeling is repeated 10 times in the same place with the same member, and the measurement value of the last 10th time is taken as the peeling force after the repetition.

[Prevention of fuzz on the outer surface of the diaper (initial, after repeated)]
For fluffing, the surface of the non-woven fabric after the peel force evaluation was visually observed by 10 monitors and evaluated according to the following criteria.
◎: No fuzz ○: Slightly fuzzy but not clear △: Fuzzy ×: Many fuzz

[Diaper feel]
Evaluation was based on the following four steps based on the touch of the diaper on the palm. The results were carried out on 10 monitors, and the average was shown.
Criteria 4: There is a soft and smooth feeling.
3: Slightly soft. There is a little smooth feeling.
2: Slightly hard. There is a little resistance (rough feeling).
1: Hard. There is a sense of resistance.
Evaluation result ◎: Judgment average 3.5 or more, 4 or less ○: Judgment average 2.7 or more, less than 3.5 △: Judgment average 1.7 or more, less than 2.7 ×: Judgment average 1 or more, less than 1.7

  As is clear from the results shown in Table 1, in the diaper of the example, it can be seen that the peeling force between the fastening tape and the outer surface of the diaper is higher than that of the comparative example both in the initial stage and after the repetition. In particular, it can be seen that a decrease in peel strength after repetition is prevented. Moreover, in the diaper of an Example, it turns out that the fuzz prevention property of a diaper outer surface is superior to a comparative example both in the initial stage and after repetition. In particular, it can be seen that a reduction in the prevention of fuzz after repetition is prevented. Furthermore, it turns out that the diaper of an Example is superior to the comparative example in the touch of the outer surface of a diaper.

DESCRIPTION OF SYMBOLS 10 Nonwoven fabric 18 Concave part 19 Convex part 20 Production apparatus 30 Web production part 40 Embossing part 50 Hot air spraying part 110 Disposable diaper 111 Top sheet 112 Back sheet 113 Absorber 114 Waist flap 115 Leg flap 116 Three-dimensional guard formation sheet 117 Leg elastic strand 118 Three-dimensional guard 119 Three-dimensional guard elastic member 120 Fastening tape 120a Fastening means

Claims (9)

A top sheet positioned on the skin facing surface side of the wearer, a back sheet positioned on the non-skin facing surface side, and an absorbent body interposed between the two sheets, and is substantially vertically long and has one longitudinal direction. Disposable diapers with fastening tapes extending laterally from the left and right side edges at the end of the
The fastening portion of the fastening tape is formed of a hook member of a hook-and-loop fastener, and a coating portion made of a nonwoven fabric that engages with the fastening portion is provided on the surface of the back sheet.
The nonwoven fabric includes a heat-extensible fiber whose length is extended by heating, and has a plurality of convex portions and concave portions on one surface side, and the heat-extensible fiber constituting the convex portion has a thermal elongation rate. However, the lower part is higher than the upper part of the convex part,
As the raw fiber of the heat-extensible fiber, two or more types of heat-extensible raw material fibers having different temperatures at which thermal extension is started
The upper side of the convex part is formed using a low-temperature heat-extensible raw fiber that starts thermal elongation at a relatively low temperature, and the lower part of the convex part is a high-temperature heat-extensible raw fiber that starts thermal extension at a relatively high temperature. Disposable diapers that are formed using   The thermally extensible fiber includes a first resin component made of a high melting point resin and a second resin component made of a low melting point resin having a melting point lower than the melting point of the first resin component, and the second resin component is a fiber surface. The disposable diaper according to claim 1, wherein the disposable diaper is a composite fiber in which at least a part of the fiber is continuously present in the length direction.   At the melting point + 20 ° C. of the low-melting resin constituting the heat-extensible fiber located above the convex portion, the thermal elongation rate of the heat-extensible fiber located above the convex portion is 0.1% or more and less than 3.0% The disposable diaper according to claim 1 or 2, wherein the thermal stretch rate of the heat stretchable fiber located at the lower portion of the convex portion is 3.0% or more and less than 20%.   The disposable diaper according to any one of claims 1 and 2, wherein an upper side of the convex portion includes a core-sheath type heat-stretchable conjugate fiber in which the core is polypropylene and the sheath is polyethylene.   The disposable diaper according to any one of claims 1 to 3, wherein the lower side of the convex portion includes a core-sheath type thermally stretchable conjugate fiber in which the core is polyethylene terephthalate and the sheath is polyethylene.   The upper part of the convex part includes a core-sheath type heat-extensible composite fiber in which the core is polypropylene and the sheath is polyethylene, and the lower part of the convex part is the core-sheath type heat in which the core is polyethylene terephthalate and the sheath is polyethylene. The disposable diaper according to any one of claims 1 to 3, comprising an extensible composite fiber.   The disposable diaper in any one of 1 thru | or 6 whose Young's modulus of the heat | fever extensible fiber contained in the said nonwoven fabric is 0.2-1GPa.   The disposable diaper according to any one of 1 to 7, wherein the nonwoven fabric is arranged so that a surface of the nonwoven fabric having a convex portion and a concave portion is engaged with the fastening portion. A disposable diaper comprising a top sheet positioned on the skin facing surface side of the wearer, a back sheet positioned on the non-skin facing surface side, and an absorbent body interposed between both sheets, and is substantially vertically long. ,
A non-woven fabric is disposed on the outer surface of the back sheet, the non-woven fabric includes a heat-extensible fiber whose length is extended by heating, and has a plurality of convex portions and concave portions on one surface side. The thermal stretchable fiber constituting the thermal elongation rate is higher in the lower part than in the upper part of the convex part,
As the raw fiber of the heat-extensible fiber, two types of heat-extensible raw material fibers having different temperatures at which thermal extension is started are used.
The upper side of the convex part is formed using a low-temperature heat-extensible raw fiber that starts thermal elongation at a relatively low temperature, and the lower part of the convex part is a high-temperature heat-extensible raw fiber that starts thermal extension at a relatively high temperature. Disposable diapers that are formed using

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