JP5593124B2 - 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. Further, as described in Patent Documents 1 and 2, as a fastening system, a male material of a mechanical tape is used as a fastening tape, and as an adherent member, a large number of fibers are looped on a base tape or It has been proposed to use a slightly hard knitted fabric woven in an arch shape or a non-woven fabric having a good texture. However, in the nonwoven fabrics of Patent Documents 1 and 2, in order to increase the engagement force, the touch as a nonwoven fabric is never good for reasons such as increasing the strength of the nonwoven fabric or using a fiber with a large fineness. . When the nonwoven fabric described in these documents is used as the back sheet of the disposable diaper, poor touch and poor followability with respect to movement due to hardness are problems.

  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 in the fastening tape is made of a hook member of a hook-and-loop fastener, and the attached portion made of a nonwoven fabric that engages with the fastening portion is provided on the surface of the back sheet,
The non-woven fabric includes heat-extensible fibers that are elongated by heating, and has a large number of convex portions and concave portions on one side, and the fibers constituting the convex portions have a thermal elongation rate lower than that of the lower portions of the convex portions. A disposable diaper with a higher upper part 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 that elongates by heating, and has a plurality of convex portions and concave portions on one surface side, and the heat constituting the convex portion. The extensible fiber provides a disposable diaper whose thermal elongation rate is higher in the upper part than in the lower part of the convex part.

  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 C 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 shown to Fig.4 (a) is shown by FIG.4 (b). The nonwoven fabric 10 of this embodiment 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. Therefore, the nonwoven fabric 10 is arranged on the surface of the back sheet 112 so that the surface 10a which is the surface having the convex portion 19 and the concave portion 18 of the two surfaces 10a and 10b is engaged with the fastening tape 120. Yes. 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 constituent fibers of the nonwoven fabric 10 are fused at their intersections. Since the intersections of the fibers are heat-sealed in 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, due to the increase in the inter-fiber distance, there is an advantageous effect that 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. 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. Moreover, the nonwoven fabric 10 may contain the non-heat extensible fiber. Particularly preferably used non-heat-extensible fibers include a first resin component made of a high-melting 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 is substituted. And a second resin component made of a low melting point resin, 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. The second resin component in the composite fiber is a component that exhibits heat-fusibility. Details of the heat-extensible fibers and non-heat-extensible fibers 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 fiber located in the upper part 19a of the convex part 19 and the fiber 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 fiber constituting the convex portion 19 is relatively higher in thermal expansion rate in the upper portion 19 a than in the lower portion 19 b of the convex portion 19. It is getting higher. That is, when heat at a certain temperature is applied, the fiber located at the upper part 19a of the convex portion 10 has a greater degree of thermal expansion than the fiber located at the lower part 19b. In other words, the degree of thermal expansion of the fiber located in the lower part 19b of the convex portion 10 is smaller than that of the fiber located in the upper part 19a. Since the degree of thermal expansion of the fibers contained in the convex portion 19 is such, the nonwoven fabric 10 is easily stretched by the fibers located on the front surface 10a side, and therefore before the nonwoven fabric 10 is bonded to the back sheet 112. In addition, when the function of the nonwoven fabric 10 as an adherent part and the function of the outer layer material of the diaper 10 are enhanced by processing for bulk recovery such as blowing hot air, the fiber on the surface 10a side is thermally stretched. The advantageous effect that the bulk recoverability is improved is exhibited. Further, the bulk recovery makes the inter-fiber distance on the front surface 10a side larger than the inter-fiber distance on the back surface 10b side, and there is an advantageous effect that 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. As a result, the non-woven fabric 10 is less prone to fuzzing, and the decrease in engagement force is reduced even when repeated peeling is performed. 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 fibers contained in the convex portion 19 may gradually increase from the lower portion 19b toward the upper portion 19a, or may increase 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-described effect more prominent, a heat-extensible fiber is used as at least one kind of fiber located on the upper part of the convex portion, and the melting point of the low-melting resin constituting the heat-extensible fiber is + 20 ° C. (In the case of a resin having no melting point, at a temperature of the softening point + 20 ° C.), the thermal stretch rate of the heat stretchable fiber located on the upper portion 19a of the convex portion 19 is 0.5% or more and less than 50%, particularly 0.5 % Or more and less than 20%, particularly preferably 0.9% or more and less than 10%. On the other hand, the thermal elongation rate of the fiber located in the lower portion 19b of the convex portion 19 is −50% or more and less than 0.5%, particularly −20% or more and less than 0.5%, especially −10% at the above temperature. As mentioned above, it is preferable that it is less than 0.4%. This thermal elongation rate is measured for the fibers contained in the convex portion 19. A method for measuring the thermal elongation rate will be described later. A negative value for the thermal elongation means that the fiber shrinks due to heat.

  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 is defined as the softening point as the temperature at which the second resin component begins to flow.

  As a fiber used as the raw material of the nonwoven fabric 10, a heat | fever extensible fiber can be 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. Moreover, as a fiber used as the raw material of the nonwoven fabric 10, in addition to the heat-extensible raw material fiber, a non-heat-extensible fiber can be used. In the following description, the non-heat-extensible fiber contained in the nonwoven fabric 10; For the purpose of distinguishing the non-heat-extensible fibers that are the raw material of the nonwoven fabric 10, the non-heat-extensible fibers that are the raw material of the nonwoven fabric 10 are referred to as “non-heat-extensible raw fibers”. When it is simply referred to as “non-heat-extensible fiber”, it refers to a non-heat-extensible fiber contained in the nonwoven fabric 10.

  It is preferable to use a combination of a heat-extensible raw material fiber and a non-heat-extensible raw material fiber as a raw material for the nonwoven fabric 10. In this case, it is preferable that the upper part 19a side of the convex part 19 is formed using a heat-extensible raw material fiber, and the lower part 19b side of the convex part 19 is formed using a non-heat-extensible raw material fiber. The blending ratio (weight) of both is expressed as a ratio of heat-extensible raw fiber: non-heat-extensible raw fiber, preferably 95: 5 to 5:95, more preferably 80:20 to 20:80, and still more preferably. Is from 60:40 to 40:60, more preferably from 55:45 to 45:55. A preferred method for producing the nonwoven fabric 10 will be described later.

  As the fiber used as the raw material of the nonwoven fabric 10, two types of heat-extensible raw material fibers having different temperatures at which thermal expansion starts can be used. In other words. A heat-extensible raw fiber that stretches at a relatively high temperature (hereinafter referred to as “high-temperature stretchable raw fiber”) and a heat-extensible raw fiber that stretches at a relatively low temperature (hereinafter “low-temperature stretchable raw fiber”) Say). 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 high-temperature-extensible raw material fibers, and the lower portion 19b side of the convex portion 19 is formed using low-temperature extensible raw material fibers. It is preferable to be formed. The blending ratio (weight) of both is expressed as a ratio of high-temperature-extensible raw fiber: low-temperature-extensible raw fiber, preferably 95: 5 to 5:95, more preferably 80:20 to 20:80, and still more preferably. 60:40 to 40:60, still more preferably 55:45 to 45:55.

  The heat-extensible raw fiber (including the low-temperature extensible raw fiber and the high-temperature 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 component component made of a low melting point resin having a softening point, wherein the second resin component is present continuously in the length direction at least part of the fiber surface (hereinafter referred to as this component). The fiber 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-extensible composite raw fiber has a thermal elongation rate of 0.5 to 20%, particularly 3 to 20%, especially 5 to 20% at a temperature 10 ° C higher than the melting point or softening point of the second resin component. Is preferred. The nonwoven fabric 10 manufactured using fibers with such an elongation rate as a raw material becomes bulky due to the elongation of the fibers in the manufacturing process of the nonwoven fabric 10 or has a three-dimensional appearance. 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 length of 10 mm or more collected so that the total weight per fiber length of 10 mm is 0.5 mg, and arranging the plurality of fibers in parallel, Mount on the device with 10mm distance between chucks. 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 fiber elongation at that time is measured, and the amount of elongation X (mm) at a temperature 10 ° C. higher than the melting point of the second resin component and at a temperature 10 ° C. higher than the softening point is read in the case of a resin having no melting point.
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%.

  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.

  When two types of heat-extensible raw fiber are used, the upper portion 19a side of the convex portion 19 of the nonwoven fabric 10 includes a core-sheath type heat-extensible composite fiber in which the core is polyethylene terephthalate and the sheath is polyethylene, and the convex portion 19 includes a core-sheath type heat-stretchable composite fiber in which the core is polypropylene and the sheath is polyethylene, so that the bulk recovery of the nonwoven fabric 10 when hot air is blown onto the nonwoven fabric 10 can be made more remarkable. To preferred.

  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.

  When using a heat-extensible raw material fiber and a non-heat-extensible raw material fiber in combination, the non-heat-extensible raw material fiber is composed of two components having different melting points and is subjected to a drawing treatment. It is preferable to use a fusible conjugate fiber. The heat-fusible conjugate fiber does not substantially extend its length even when heat is applied. In some cases, it may shrink slightly. The non-thermally stretchable raw fiber has a thermal stretch rate at a temperature 20 ° C. higher than the melting point or softening point of the second resin component of −50% to 0.5%, particularly −20 to 0.4%, especially −10. % To 0.1% is preferable. This heat-fusible conjugate fiber is a bicomponent conjugate fiber that includes a high-melting-point component and a low-melting-point component, and the low-melting-point component is continuously present in the length direction on at least a part of the fiber surface. . There are various forms of the composite fiber such as a core-sheath type and a side-by-side type, and any form can be used. The heat-fusible conjugate fiber is stretched at the raw material stage (that is, before being used for the nonwoven fabric 10). The stretching treatment referred to here is, for example, a stretching operation with a stretching ratio of about 2 to 6 times.

  The fiber lengths of the heat-extensible raw material fiber and the non-heat-extensible raw material fiber are of appropriate lengths depending on 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. On the other hand, the fiber diameter of the non-heat-extensible fibers contained in the nonwoven fabric 10 is 10 to 35 μm, particularly 15 to 30 μm, particularly 15 to 15 μm when the nonwoven fabric 10 is used as a constituent member of an absorbent article such as a surface sheet of the absorbent article. It is preferable that it is 25 micrometers.

  In addition to the fibers described above, the nonwoven fabric 10 may additionally include, for example, fibers that do not inherently have heat-fusibility (for example, natural fibers such as cotton and pulp, rayon, and acetate fibers).

The nonwoven fabric 10 has a basis weight of 10 to 80 g / m ² , particularly 15 to 60 g / m ² , especially 20 to 20% when the nonwoven fabric 10 is used as a constituent member of an absorbent article such as a surface sheet of the absorbent article. 40 g / m ² is preferred. When used for the same application, the thickness of the nonwoven fabric 10 is preferably 0.5 to 3 mm, particularly 0.7 to 3 mm after bulk recovery by hot air (this will be described later). The thickness of the nonwoven fabric was measured by the method described later.

  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 part 30, the web 10a is manufactured using the heat | fever extensible raw material fiber and the non-heat extensible raw material fiber as needed. As the heat-extensible raw fiber, it is preferable to use a two-component composite fiber including the first resin component and the second resin component described above.

  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 heat-extensible raw fiber. The card machine 31b is supplied with non-heat-extensible raw fiber. When two types of heat-extensible fibers are used, the card machine 31a is supplied with high-temperature-extensible raw fiber, and the card machine 31b is supplied with low-temperature-extensible raw fiber.

  The webs formed by the respective card machines are laminated to form a web 10a. In the web 10a, the heat-extensible raw fiber is located in the upper layer, and the non-heat-extensible raw fiber is located in the lower layer. When two types of heat-extensible fibers are used, the high-temperature-extensible raw fiber is located in the upper layer, and the low-temperature-extensible raw fiber is located in the lower layer. The fibers located in the upper layer of the web 10a mainly constitute the upper side 19a of the convex portion 19 of the manufactured nonwoven fabric 10. The fibers located in the lower layer of the web 10a mainly constitute the lower side 19b of the convex portion 19. In the following description, the surface of the web 10a where the heat-extensible raw fiber (or high-temperature extensible raw fiber) is present is referred to as the first surface 101, and the non-heat-extensible raw fiber (or low-temperature extensible raw material) is used. The surface on the side where the (fiber) exists is called a second surface 102. 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. Both rolls are separated by a predetermined clearance. 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 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 to produce the embossed web 10b. 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.

  In the embossing section 40, when heating at least one of the pattern roll 41 and the flat roll 42, the heating temperature is preferably set as follows. That is, when the combination of the heat-extensible raw fiber and the non-heat-extensible raw fiber is adopted, the melting point of the second resin component in the heat-extensible raw fiber is −20 ° C. or higher and lower than the melting point of the first resin component. It is preferable. When the combination of the high-temperature-extensible raw fiber and the low-temperature-extensible raw fiber is employed, the melting point of the second resin component in the low-temperature-extensible raw fiber is preferably −20 ° C. or higher and lower than the melting point of the first resin component. .

  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 made of metal or resin such as polyamide and 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 (the high-temperature extensible raw fiber and the low-temperature extensible raw fiber) in the embossed web 10b is elongated by heating. In addition, the intersection of the heat-extensible raw fibers (high-temperature-extensible raw fibers and low-temperature-extensible raw fibers) in a free state existing in a portion other than the embossed portion of the embossed web 10b and the non-heat-extensible raw fibers are heat-sealed. Done at the temperature you want.

  The temperature of the hot air is preferably set as follows. That is, when a combination of a heat-extensible raw fiber and a non-heat-extensible raw fiber is adopted, the temperature is set so that the heat-extensible raw fiber is thermally extended. Further, the temperature is set such that the heat-extensible raw fiber is fused and the non-heat-extensible raw fiber is fused. Specifically, the temperature of the hot air is preferably not lower than the melting point of the second resin component of the 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 heat-extensible raw fiber is elongated. On the other hand, the non-heat stretchable fiber does not substantially stretch and maintains the original length substantially. Since a part of the heat-extensible raw fiber is fixed by the embossed portion, the stretched portion is a portion between the embossed portions. Further, since a part of the heat-extensible raw fiber is fixed by the embossed portion, the stretch of the stretched fiber loses its place in the plane direction of the embossed web 10b, and in the thickness direction of the embossed web 10b. Moving. 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. Further, the intersections of the heat-extensible raw material fibers are fused, and the intersection points of the non-heat-extensible raw material fibers are fused.

  On the other hand, when the combination of the high-temperature-extensible raw material fiber and the low-temperature-extensible raw material fiber is adopted, the temperature of the hot air is set to a temperature at which both the high-temperature-extensible raw material fiber and the low-temperature-extensible raw material fiber are thermally extended. Moreover, it is set as the temperature which high temperature extensibility raw material fibers fuse | melt and low temperature extensibility raw material fibers fuse | melt. Specifically, the temperature of the hot air is preferably not lower than the melting point of the second resin component of the low-temperature-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 stretchable raw fiber and the high-temperature stretchable raw fiber are stretched. And the convex part 19 is formed between embossed parts resulting from the expansion | extension, 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 intersections of the high-temperature-extensible raw fibers are fused, and the intersections of the low-temperature-extensible raw fibers are fused.

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

  When a combination of heat-extensible raw fiber and non-heat-extensible raw fiber is used, the blowing of hot air is completed before the heat-extensible raw fiber is fully extended. In addition, the heat-extensible raw fiber can be further extended. On the other hand, the non-heat-stretchable raw fiber does not substantially stretch even when heat treatment is further performed. For this reason, in the obtained nonwoven fabric 10, the fiber constituting the convex part 19 has a higher thermal elongation rate measured at the same temperature in the upper part 19 c than in the lower part 19 b of the convex part 19.

  When a combination of high-temperature-stretchable raw fiber and low-temperature-stretchable raw fiber is used, the degree of elongation of the low-temperature-stretchable raw fiber is higher than that of the high-temperature-stretchable raw fiber due to the lower temperature at which stretching starts. Becomes larger. As a result, when the heat treatment is further performed, the low-temperature-extensible raw fiber has a lower thermal elongation rate, so that the thermal elongation rate is relatively low. In other words, when the heat treatment is further performed, the high-temperature-extensible raw fiber has a larger thermal expansion elongation ratio, so that the elongation ratio is relatively high. For this reason, in the obtained nonwoven fabric 10, the fiber constituting the convex portion 19 has a higher thermal elongation rate measured at the same temperature in the upper portion 19 a than in the lower portion 19 b of the convex portion 19.

  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 first resin component in the heat-stretchable composite fiber and a temperature equal to or higher than the melting point −50 ° C. as the hot air blown to the nonwoven fabric 10. When two types of heat-extensible raw material fibers are used, it is preferable to use hot air having a temperature lower than the melting point of the first resin component in the low-temperature extensible raw material fibers and a temperature of the melting point −50 ° C. or higher. 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 stuck to the back sheet 112 is still higher in the thermal elongation rate than in the lower 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 112, it replaces with this and the surface 10a of the nonwoven fabric 10 is facing the back sheet 112 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 heat-extensible raw fiber, a heat-extensible raw fiber (fineness 4 dtex, heat elongation rate 7.9%) in which the core shown in Table 1 is polypropylene (melting point 161 ° C.) and the sheath is polyethylene (melting point 126 ° C.) is used. A first card web having a basis weight of 20 g / m ² was produced. Separately from this, as the non-heat-extensible raw fiber shown in Table 1, a heat-fusible composite fiber (4 dtex, heat elongation rate) having a core made of polyethylene terephthalate (melting point 250 ° C.) and a sheath made of polyethylene (melting point 126 ° C.). -1.3%), a second card web having a basis weight of 20 g / m ² 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 (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, Young's modulus, 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, Young's modulus, 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, Young's modulus, 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.

[Peeling force between fastening tape and diaper outer surface (initial, after repeated)]
The fastening tape to which the surface fastener is attached is cut out from the produced disposable diaper, and is placed on the non-woven fabric on the back sheet so as to be 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.
Judgment criteria 4: 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 A: Judgment average 3.5 or more, 4 or less B: Judgment average 2.7 or more, less than 3.5 Δ: 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 (7)

Comprising a topsheet which is positioned on the skin facing side of the wearer, and the back sheet positioned on the non-skin facing side, and an absorbent body interposed between the two sheets, a longitudinal length shape, longitudinal one end Disposable diapers with fastening tapes extending laterally from the left and right side edges of the part,
The fastening portion in the fastening tape is made of a hook member of a hook-and-loop fastener, and the attached portion made of a nonwoven fabric that engages with the fastening portion is provided on the surface of the back sheet,
The non-woven fabric includes a heat-extensible fiber that has been stretched by heat treatment , and has a large number of convex portions and concave portions on one surface side, and the fiber constituting the convex portion has a thermal elongation rate lower than the convex portion. It has become higher in the upper than,
The nonwoven fabric is a disposable diaper arranged on the surface of the back sheet so that a surface of the surface having the convex portion and the concave portion is engaged with the fastening portion . On the upper part of the convex part, as a heat-extensible fiber, a heat-extensible composite fiber containing a high-melting resin and a low-melting resin having a lower melting point is located,
At the melting point of the low-melting point resin + 20 ° C., the thermal stretch rate of the thermally stretchable conjugate fiber located on the top of the convex portion is 0.5% or more and less than 50%,
The disposable diaper according to claim 1, wherein the thermal elongation rate of the fiber located at the lower part of the convex part is -50% or more and less than 0.5%.   The disposable diaper according to claim 1 or 2, wherein the upper side of the convex part is formed using a heat-extensible raw material fiber, and the lower side of the convex part is formed using a non-heat-extensible raw material fiber.   The upper part of the convex part is formed using a heat-extensible raw material fiber that thermally expands at a relatively high temperature, and the lower part of the convex part is formed using a heat-extensible raw material fiber that heat-extends at a relatively low temperature. The disposable diaper according to claim 1 or 2. The disposable diaper according to any one of claims 1 to 4, wherein the Young's modulus of the heat-extensible fiber contained in the nonwoven fabric is 0.2 to 1 GPa. The disposable diaper according to any one of claims 1 to 5, wherein the heat-extensible fibers are present in the nonwoven fabric in a state that can be stretched by heating. A topsheet positioned on the skin facing side of the wearer, and the back sheet positioned on the non-skin facing side, and a absorbent body interposed between the two sheets, a disposable diaper are longitudinal length shape,
A non-woven fabric is disposed on the outer surface of the back sheet, the non-woven fabric includes a heat-extensible fiber stretched by heat treatment , has a number of convex portions and concave portions on one surface side, and constitutes the convex portion. The heat-extensible fiber has a higher thermal elongation rate in the upper part than in the lower part of the convex part ,
The nonwoven fabric is a disposable diaper arranged on the surface of the back sheet so that a surface of the surface having the convex portion and the concave portion is engaged with the fastening portion .