JP4889439B2 - Elastic nonwoven fabric - Google Patents

Description

  The present invention relates to a stretchable nonwoven fabric.

Conventionally, an elastic nonwoven fabric provided with at least an elastic fiber layer has been used (for example, see Patent Document 1 below). The stretchable nonwoven fabric described in Patent Document 1 is formed by joining an elastic stretchable first fiber layer and a non-stretchable second fiber layer.
By the way, in an elastic nonwoven fabric, when extending in the machine direction (MD direction) at the time of manufacture, there is little width shrinkage (neck-in) and it is desired that workability is high. Further, for example, in the case where a stretchable nonwoven fabric is used for the sheet constituting the outer surface of the disposable diaper, the modulus in the MD direction is large at a desired site in the direction orthogonal to the MD direction (CD direction), and the stretch property in the MD direction. Is desired to be excellent.
However, in the stretchable nonwoven fabric described in Patent Document 1, since the elastic stretchable first fiber layer has a substantially uniform thickness, the above-described reduction in width shrinkage and excellent stretch characteristics in the MD direction are described. Cannot be achieved.

  Conventionally, various methods for producing a striped sheet have been known (for example, see Patent Documents 2 to 5 below). In the manufacturing methods described in Patent Documents 2 and 3, a sheet having a striped pattern is formed by providing a wide portion and a narrow portion in the flow path in the cooling and stretching apparatus and controlling the flow velocity of the airflow. In the manufacturing method described in Patent Document 4, a sheet having a striped pattern is formed using an electrostatic charging effect in a spunbond method. In the manufacturing method described in Patent Document 5, air is blown into the flow path inside the cooling and stretching apparatus, and the flow rate of the airflow is controlled to form a sheet having a striped pattern.

  However, in the manufacturing methods described in Patent Documents 2 and 3, since the fibers are easily caught in the narrow portion of the flow path, it is difficult to apply to elastic fibers that are highly sticky and easily agglomerate. When an elastic fiber is applied to the manufacturing method described in Patent Document 4, it tends to become a lump. As in the manufacturing method described in Patent Document 5, it is difficult to control the flow velocity of the airflow with a method in which air is blown into the flow path inside the cooling and stretching apparatus. Thus, none of the manufacturing methods described in Patent Documents 2 to 5 are suitable for manufacturing a sheet made of elastic fibers.

JP 2001-159062 A JP 2001-32161 A JP 50-138115 A Japanese Patent Laid-Open No. 7-109658 JP 52-59775 A

  Accordingly, an object of the present invention is to provide a stretchable nonwoven fabric and a method for producing the same that can eliminate the various disadvantages of the above-described prior art. Moreover, the objective of this invention is providing the disposable diaper using the said elastic nonwoven fabric.

  The present invention is a stretchable nonwoven fabric provided with at least an elastic fiber layer, and in a non-stretched state, the elastic fiber layer has a high basis weight having a relatively high basis weight in the CD direction perpendicular to the machine direction during production. The object is achieved by providing a stretchable nonwoven fabric in which portions and low basis weight portions having relatively low basis weights are alternately arranged.

  The present invention also provides a method for producing the stretchable nonwoven fabric using a spinning device capable of melt spinning an elastic fiber made of a thermoplastic elastomer, the spinning device comprising a spinning nozzle hole diameter, a spinning nozzle land length. And at least one of the hole pitches of the spinning nozzles is different in the CD direction, whereby the spinning mass of the elastic fiber per unit width includes a part where the spinning mass is large and a part where the spinning mass is small in the CD direction. By providing a method for producing a stretchable nonwoven fabric by spinning elastic fibers, forming the spun elastic fibers on a conveyor to form a stretched fiber sheet, and then manufacturing the stretchable nonwoven fabric from the stacked fiber sheet The object has been achieved.

  The present invention also relates to a method for producing the stretchable nonwoven fabric using a spinning device capable of melt spinning elastic fibers made of a thermoplastic elastomer, wherein the elastic fibers are spun and spun by the spinning device. In addition, by directly blowing air having a high speed portion and a low speed portion in the CD direction, the elastic fiber is stretched, and in the air transport state, the elastic fiber has a mass large and small in the CD direction. The above object is achieved by providing a method for producing a stretchable nonwoven fabric, which forms a stretched nonwoven sheet from the piled sheet after forming the portion and forming the stacked fiber sheet by stacking the elastic fibers. Is.

  The present invention also relates to a method for producing the stretchable nonwoven fabric using a spinning device capable of melt spinning elastic fibers made of a thermoplastic elastomer, wherein the elastic fibers are spun and spun by the spinning device. Is sucked by air having a high-speed part and a low-speed part in the CD direction, thereby forming a part having a large mass and a part having a small mass in the CD direction in the air conveying state. The object is achieved by providing a method for producing a stretchable nonwoven fabric in which the stretchable nonwoven fabric is produced from the piled sheet after forming fibers by stacking fibers.

  Moreover, this invention achieves the said objective by providing the disposable diaper in which the said elastic nonwoven fabric was used as a sheet | seat for providing elastic elasticity to the waist part of a disposable diaper.

According to the stretchable nonwoven fabric of the present invention, when stretched in the machine direction (MD direction) at the time of manufacture, there is little width shrinkage (neck-in) and the workability is high. Moreover, in the desired part in the direction orthogonal to the MD direction (CD direction), the modulus in the MD direction is large, and the stretch property in the MD direction is excellent. A nonwoven fabric can be manufactured easily.
According to the disposable diaper of the present invention, the stretchability of the waistline portion is excellent.

Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. Fig.1 (a) is a schematic diagram which shows the cross-section of 1st Embodiment of the elastic nonwoven fabric of this invention, FIG.1 (b) is a top view which shows the elastic nonwoven fabric of 1st Embodiment. The stretchable nonwoven fabric 10 of the first embodiment has a single-layer structure composed of only the elastic fiber layer 1 as shown in FIG. In the non-stretched state, the elastic fiber layer 1 has a relatively high basis weight in the CD direction perpendicular to the machine direction (MD direction) at the time of manufacture, as shown in FIGS. High basis weight portions 12 and low basis weight portions 13 having relatively low basis weights are alternately arranged.
In order to form the high basis weight portion 12 and the low basis weight portion 13, that is, to make the basis weight partially different (depending on the position), the amount of the constituent fibers may be changed. Different lengths, fiber diameters, etc. In 1st Embodiment, as shown to Fig.1 (a), the high basic weight part 12 is thick, and the low basic weight part 13 is thin.

The basis weight of the high basis weight portion 12 is preferably 5 to 60 g / m ² , particularly preferably 10 to 40 g / m ² . The basis weight of the low basis weight portion 13 is preferably 2.5 to 54 g / m ² , particularly preferably 3 to 30 / m ² . The basis weight of the low basis weight portion 13 is preferably 5 to 90% of the basis weight of the high basis weight portion 12, and more preferably 12 to 75%.

  The thickness of the high basis weight portion 12 is preferably 0.05 to 2 mm, particularly preferably 0.1 to 0.5 mm. The thickness of the low basis weight portion 13 is preferably 0.03 to 1.5 mm, and particularly preferably 0.05 to 0.3 mm. The thickness can be measured by observing the cross section with a microscope at a magnification of 50 to 200 times, obtaining the average thickness in each visual field, and obtaining the average thickness of the three visual fields.

  The fiber diameters of the constituent fibers of the high basis weight portion 12 and the low basis weight portion 13 are preferably 5 μm or more, particularly preferably 10 μm or more, and preferably 100 μm or less, particularly 40 μm or less, from the viewpoint of stretch properties.

Although the planar view shape of the high basic weight part 12 and the low basic weight part 13 changes with the formation methods, in this embodiment, it is strip | belt shape. In the present embodiment, each high basis weight portion 12 has a uniform width, and similarly, each low basis weight portion 13 has a uniform width.
Along the CD direction, the width of the high basis weight portion 12 is preferably 5 to 100 mm, and more preferably 10 to 40 mm. Moreover, it is preferable that the width | variety of the low basic weight part 13 is 5-100 mm, and it is still more preferable that it is 10-40 mm.

  The elastic fiber layer 1 has a property that it can be stretched and contracts when released from the stretched force. The elastic fiber layer 1 preferably has a residual strain of 20% or less, particularly 10% or less when contracted after 100% elongation in at least one direction parallel to the surface. This value is preferably satisfied in at least one of the MD direction and the CD direction, and more preferably satisfied in both directions.

  The elastic fiber layer 1 is an aggregate of fibers having elasticity. In the elastic fiber layer 1, inelastic fibers may be blended in an amount of preferably 30% by weight or less, more preferably 20% by weight or less, and even more preferably 10% by weight or less as long as the elasticity is not impaired. . The fiber having elasticity may be a continuous filament (continuous fiber) or a short fiber. Examples of a method for forming an elastic fiber include a melt blown method in which a molten resin is extruded from a nozzle hole, and the extruded molten resin is elongated by blowing hot air, thereby thinning the fiber, and a semi-molten resin There is a spunbond method in which the film is stretched by blowing cold air or by a mechanical draw ratio. There is also a spinning blow method which is a kind of melt spinning method.

  The elastic fiber layer 1 may be in the form of a web or a nonwoven fabric made of elastic short fibers or continuous filaments. For example, it may be a web or a non-woven fabric formed by a spinning blow method, a spun bond method, a melt blow method, or the like. In the elastic fiber layer 1, it is preferable that the intersection of the constituent fibers is thermally fused in the layer.

  As a constituent fiber of the elastic fiber layer 1, for example, a fiber made from a thermoplastic elastomer or rubber can be used. In particular, fibers made from thermoplastic elastomers are preferred because they can be melt-spun using an extruder in the same manner as ordinary thermoplastic resins, and the fibers thus obtained are easily heat-sealed. Examples of the thermoplastic elastomer include styrene elastomers such as SBS, SIS, SEBS, and SEPS, olefin elastomers, polyester elastomers, and polyurethane elastomers. These can be used individually by 1 type or in combination of 2 or more types. A core-sheath type or side-by-side type composite fiber made of these resins can also be used. In view of moldability, elastic properties and cost of the elastic fiber, it is particularly preferable to use a styrene elastomer, an olefin elastomer, or a combination thereof.

  The stretchable nonwoven fabric 10 of this embodiment has stretchability in at least one direction in the in-plane direction, and may have stretchability in all in-plane directions. In that case, it is not hindered that the degree of elasticity varies depending on the direction. With respect to the direction of expansion and contraction, the degree of elasticity is preferably 20 to 500 cN / 25 mm, particularly 40 to 150 cN / 25 mm, at 100% elongation. Further, the residual strain when contracted from the 100% stretched state is preferably 15% or less, particularly preferably 10% or less.

According to the stretchable nonwoven fabric 10 of the first embodiment, due to the arrangement of the high basis weight portion 12 and the low basis weight portion 13 in the elastic fiber layer 1, when stretched in the machine direction (MD direction) at the time of manufacture. The width shrinkage (neck-in) is small and the workability is high. Moreover, in a desired part in a direction orthogonal to the MD direction (CD direction), the modulus in the MD direction is large, and the expansion and contraction characteristics in the MD direction are excellent. These points are supported by the evaluation results using Examples and Comparative Examples described later.
Moreover, since the low basis weight portion 13 is excellent in air permeability, the air permeability of the entire stretchable nonwoven fabric 10 is also excellent. In the form in which the elastic fiber layer 1 is exposed as in the first embodiment, light and shade are formed from the high basis weight portion 12 and the low basis weight portion 13, and the appearance is also excellent.

Next, the 1st embodiment of the manufacturing method of the elastic nonwoven fabric of this invention used preferably for manufacture of the elastic nonwoven fabric of 1st Embodiment is demonstrated. Fig.2 (a) is a typical side view which shows the 1st embodiment of the manufacturing method of the elastic nonwoven fabric of this invention, FIG.2 (b) is a perspective view which shows the spinning apparatus in a 1st embodiment. .
The elastic nonwoven fabric manufacturing method of the first embodiment uses a spinning device 22 that can melt-spin elastic fibers 1A made of a thermoplastic elastomer, as shown in FIG. The spinning device 22 in the present embodiment is a melt blown spinning die that performs spinning by the melt blown method. In the spinning device 22, at least one of the hole diameter of the spinning nozzle 22A, the land length of the spinning nozzle 22A (nozzle hole length), and the hole pitch of the spinning nozzle 22A differs in the CD direction. The fiber 1A has a portion where the spinning mass is large and small in the CD direction. In the spinning device 22, two or three elements of the hole diameter of the spinning nozzle 22A, the land length of the spinning nozzle 22A, and the hole pitch of the spinning nozzle 22A may be different in the CD direction, and only one element is in the CD direction. May be different.

The larger the hole diameter of the spinning nozzle 22A, the larger the fiber diameter of the elastic fiber 1A to be spun. Further, the smaller the land length of the spinning nozzle 22A, the greater the spinning amount. Further, the smaller the hole pitch of the spinning nozzle 22A, the smaller the fiber pitch of the elastic fiber 1A to be spun. Therefore, in the spinning device 22, in the portion corresponding to the high basis weight portion 12, the hole diameter of the spinning nozzle 22A is increased, the land length of the spinning nozzle 22A is shortened, and / or the hole pitch of the spinning nozzle 22A is decreased.
On the other hand, in the spinning device 22, the hole diameter of the spinning nozzle 22A is reduced, the land length of the spinning nozzle 22A is increased, and / or the hole pitch of the spinning nozzle 22A is increased in the portion corresponding to the low basis weight portion 13. .
Since the spinning nozzle 22A of the spinning device 22 has such a configuration, the spinning device 22 can have a portion where the spinning mass of the elastic fiber 1A per unit width is large and small in the CD direction.

In the manufacturing method of the first embodiment, as shown in FIG. 2, the elastic fiber 1A is spun by the spinning device 22, the spun elastic fiber 1A is piled on the conveyor 29, and a piled sheet (elastic) After forming the fiber web) 1 ′, the stretchable nonwoven fabric 10 of the first embodiment is manufactured from the piled sheet 1 ′.
In the spinning device 22, a pair of hot air discharge portions 28A are disposed opposite to each other around the spinning nozzle 22A near the tip of the spinning nozzle 22A. Therefore, hot air blowing air F1 is blown to the elastic fiber 1A spun from the spinning nozzle 22A to reduce the fiber diameter of the elastic fiber 1A and to impart an air conveying force to the elastic fiber 1A. The conveyor 29 includes a conveyor belt 29A having a net-shaped transport surface and a vacuum mechanism 29B that generates suction air F2 through the conveyor belt 29A.

In the manufacturing method of the first embodiment, the elastic fiber 1A is spun by the spinning device 22, and the blown air F1 having a high speed portion and a low speed portion in the CD direction is applied to the spun elastic fiber 1A. By directly spraying, the elastic fiber 1A is stretched, and a part having a large mass in the CD direction and a part having a small mass are formed in the elastic fiber 1A in the air conveyance state. The higher the flow velocity of the blowing air F1, the larger the mass of the elastic fiber 1A that is stacked. Therefore, in the spinning device 22, the flow rate of the blowing air F <b> 1 is increased (high speed) with respect to the elastic fiber 1 </ b> A corresponding to the high basis weight portion 12.
Conversely, the slower the flow rate of the blowing air F1, the smaller the mass of the elastic fiber 1A that is stacked. Therefore, in the spinning device 22, the flow rate of the blowing air F <b> 1 is made slower (lower) with respect to the elastic fiber 1 </ b> A corresponding to the low basis weight portion 13.

Furthermore, in the manufacturing method of the first embodiment, the elastic fiber 1A is spun by the spinning device 22, and the spun elastic fiber 1A is sucked by the suction air F2 having a high speed portion and a low speed portion in the CD direction. By doing so, in the pneumatic conveying state, the elastic fiber 1A is formed with a portion having a large mass and a small portion in the CD direction. The suction air F2 is generated from the spinning device 22 toward the conveyor belt 29A by the vacuum mechanism 29B of the conveyor 29. The higher the flow velocity of the suction air F2, the larger the mass of the elastic fiber 1A that is stacked. Therefore, the flow velocity of the suction air F2 is increased (high speed) with respect to the elastic fiber 1A corresponding to the high basis weight portion 12.
On the contrary, the slower the flow rate of the suction air F2, the smaller the mass of the elastic fiber 1A to be stacked. Therefore, the flow velocity of the suction air F <b> 2 is made slower (lower) with respect to the elastic fiber 1 </ b> A corresponding to the low basis weight portion 13.

  In the first embodiment, the five elements of the hole diameter of the spinning nozzle 22A, the land length of the spinning nozzle 22A, the hole pitch of the spinning nozzle 22A, the flow velocity of the blowing air F1, and the flow velocity of the suction air F2 are set in the CD direction. However, in the method for producing a stretchable nonwoven fabric of the present invention, it is not always necessary to make all of these five elements different, and only one to four elements appropriately selected from these five elements may be made different. .

  According to the manufacturing method of the first embodiment, the hole diameter of the spinning nozzle 22A of the spinning device 22, the land length of the spinning nozzle 22A, the hole pitch of the spinning nozzle 22A, the flow rate of the blowing air F1, the flow rate of the suction air F2, etc. Therefore, the stretchable nonwoven fabric 10 according to the first embodiment in which the high basis weight portions 12 and the low basis weight portions 13 are alternately arranged can be easily manufactured.

  In the manufacturing method of the first embodiment, the melt blown spinning die 22 is used as the spinning device. Instead, the spun bond die 22 ′ by the spun bond method or the spinning blow die 22 ″ by the spinning blow method is used. be able to.

  According to the spunbond method using the spunbond die 22 ′, as shown in FIG. 3, the semi-molten elastic fiber 1 </ b> A can be drawn by cold air blowing air F <b> 3 or a mechanical draw ratio. The cold air blowing air F3 is blown by the ejector 28B.

  As shown in FIG. 4, in the spinning blown die 22 ″, a pair of hot air discharge portions 28A are disposed near the tip of the spinning nozzle 22A so as to face each other centering on the spinning nozzle 22A, and a pair of cold air is disposed downstream thereof. The discharge portion 28C is disposed opposite to the spinning nozzle 22A. Therefore, according to the spinning blow method using the spinning blow die 22 ″, the hot air blowing air F1 and the cold air blowing air F3 are heated by the hot air F1. Since the melted elastic fiber 1A is stretched and the elastic fiber 1A is cold-drawn continuously by the cold air F3, there is an advantage that the elastic fiber can be easily formed. Further, since the fibers do not become too dense and elastic fibers having a thickness similar to short fibers can be formed, there is also an advantage that an elastic nonwoven fabric with high air permeability can be obtained. Further, according to the spinning blow method, a continuous filament web can be obtained. The continuous filament web can also be formed by laminating melt-spun filaments directly or niped to the web. Continuous filament webs are less susceptible to breakage at high elongation than short fiber webs, and tend to exhibit elasticity.

  Examples of spinning dies used in the spinning blow method include those described in FIG. 1 of JP-B 43-30017, those shown in FIG. 2 of JP-A 62-90361, and JP-A 3-3. The one described in FIG. 2 of JP-A-1717408 can be used. Furthermore, what is shown by FIG. 2 of Unexamined-Japanese-Patent No. 3-174008, and what is shown by FIG. 1 thru | or FIG. 3 of patent 3335949 can be used.

  A plurality of dies constituting the spinning device 22 can be provided in the CD direction. Accordingly, it is possible to realize a configuration in which the hole diameter of the spinning nozzle 22A, the land length of the spinning nozzle 22A, the hole pitch of the spinning nozzle 22A, the flow velocity of the blowing air F1, the flow velocity of the suction air F2, and the like are made different in the CD direction.

Next, a second embodiment of the stretchable nonwoven fabric of the present invention will be described. Fig.5 (a) is a schematic diagram which shows the cross-section of 2nd Embodiment of the elastic nonwoven fabric of this invention, FIG.5 (b) is a top view which shows the elastic nonwoven fabric of 2nd Embodiment.
As shown in FIG. 5, the stretchable nonwoven fabric 10 of the second embodiment has a two-layer structure in which a substantially inelastic non-elastic fiber layer 2 is laminated on one surface of the elastic fiber layer 1. The elastic fiber layer 1 in the second embodiment has the same configuration as the stretchable nonwoven fabric 10 (elastic fiber layer 1) of the first embodiment having a single-layer structure before the non-elastic fiber layer 2 is laminated. ing. Therefore, the description regarding the elastic fiber layer 1 in the first embodiment is appropriately applied to the elastic fiber layer 1 in the second embodiment before the non-elastic fiber layer 2 is laminated.
On the other hand, the description regarding the elastic fiber layer 1 in the second embodiment is also appropriately applied to the elastic fiber layer 1 in the first embodiment.

In the second embodiment, the elastic fiber layer 1 and the non-elastic fiber layer 2 are joined by thermal fusion of fiber intersections in a state where the constituent fibers of the elastic fiber layer 1 maintain the fiber form. The elastic fiber layer 1 and the non-elastic fiber layer 2 are preferably bonded all over.
The stretchability of the stretchable nonwoven fabric 10 of the second embodiment is manifested by subjecting the laminated fiber sheet obtained by joining the elastic fiber layer 1 and the inelastic fiber layer 2 to stretching. Specifically, the stretchability was obtained by joining the elastic fiber layer 1 and the non-elastic fiber layer 2 by thermal fusion at the fiber intersection in a state where the constituent fibers of the elastic fiber layer 1 maintained the fiber form. It is expressed by subjecting the laminated fiber sheet to stretching (details will be described later).

  The inelastic fiber layer 2 has extensibility, but is substantially inelastic. The term “extensibility” as used herein refers to the case where the constituent fiber itself is stretched, and even if the constituent fiber itself is not stretched, the two fibers that have been heat-sealed at the intersection of the fibers are separated from each other, The three-dimensional structure formed by a plurality of fibers may be structurally changed due to fusion or the like, or the constituent fibers may be broken, and the entire fiber layer may be elongated.

  Examples of the fibers constituting the inelastic fiber layer 2 include fibers made of polyethylene (PE), polypropylene (PP), polyester (PET or PBT), polyamide, and the like. The fibers constituting the inelastic fiber layer 2 may be short fibers or long fibers, and may be hydrophilic or water repellent. Further, core-sheath type or side-by-side composite fibers, split fibers, irregularly shaped cross-section fibers, crimped fibers, heat-shrinkable fibers, and the like can also be used. These fibers can be used singly or in combination of two or more. The inelastic fiber layer 2 may be a continuous filament, a short fiber web, or a non-woven fabric. In particular, a short fiber web is preferable because a thick and bulky inelastic fiber layer 2 can be formed. In the case of the core-sheath type composite fiber, it is preferable that the core is PET or PP and the sheath is low melting point PET, PP or PE. In particular, the use of these composite fibers is preferable in that heat fusion with the constituent fibers of the elastic fiber layer 1 that preferably includes a styrene-based elastomer, an olefin-based elastomer, and the like becomes strong and delamination hardly occurs.

  In the form in which the elastic fiber layer 1 and the non-elastic fiber layer 2 are bonded to each other, the constituent fibers of the elastic fiber layer 1 and the non-elastic fiber layer 1 are not at the interface between the elastic fiber layer 1 and the non-elastic fiber layer 2. The intersections with the constituent fibers of the elastic fiber layer 2 are heat-sealed, and are bonded substantially uniformly over the entire surface. By being joined all over, it is possible to prevent the floating between the elastic fiber layer 1 and the non-elastic fiber layer 2, that is, the formation of a space by separating the two layers. When floating occurs between the two layers, the sense of unity between the elastic fiber layer 1 and the non-elastic fiber layer 2 is lost, and the texture of the stretchable nonwoven fabric 10 tends to decrease. According to the form in which the elastic fiber layer 1 and the non-elastic fiber layer 2 are bonded to each other, a stretchable nonwoven fabric having a multi-layer structure with a sense of unity, such as a single nonwoven fabric, is provided.

  “The state in which the constituent fibers of the elastic fiber layer 1 maintain the fiber form” means that even if most of the constituent fibers of the elastic fiber layer 1 are given heat, pressure, etc., a film-like or film-fiber structure The state which is not deformed. There exists an advantage that sufficient breathability is provided to a stretchable nonwoven fabric because the constituent fiber of the elastic fiber layer 1 is in the state of maintaining the fiber form. As will be described later, the elastic nonwoven fabric 10 of the second embodiment is subjected to hot embossing to form a joint. In this joint part, the constituent fibers of the elastic fiber layer 1 may have a film shape or a film-fiber structure depending on the conditions of hot embossing. Therefore, whether or not “the constituent fibers of the elastic fiber layer 1 maintain the fiber form” is determined by paying attention to a portion other than the joint portion.

  In the elastic fiber layer 1, the intersections of the constituent fibers are thermally fused in the layer. Similarly, in the non-elastic fiber layer 2, the intersections of the constituent fibers are heat-sealed in the layer.

  In the non-elastic fiber layer 2, a part of the constituent fibers enters the elastic fiber layer 1 and / or a part of the constituent fibers of the elastic fiber layer 1 enters the non-elastic fiber layer 2. It is preferable. By being in such a state, integration of the elastic fiber layer 1 and the non-elastic fiber layer 2 is promoted, and the occurrence of floating between the two layers is more effectively prevented. As a result, the layers are combined with each other in a form following the surface of each layer. Part of the constituent fibers of the inelastic fiber layer enters the elastic fiber layer 1 and remains there. For example, in the non-elastic fiber layer 2, when a surface connecting the surface fibers on the side facing the elastic fiber layer 1 out of the two surfaces is assumed macroscopically, a fiber space formed inside the layer from this surface Some of the constituent fibers of the elastic fiber layer 1 have entered. Further, when the surfaces connecting the surface fibers are assumed macroscopically on the two surfaces of the elastic fiber layer 1, the constituent fibers of the non-elastic fiber layer 2 are formed in fiber spaces formed inside these layers from these surfaces. Some have entered. In particular, when the constituent fibers of the non-elastic fiber layer 2 enter the elastic fiber layer 1 and remain there, the constituent fibers of the non-elastic fiber layer 2 may be further entangled with the constituent fibers of the elastic fiber layer 1. preferable. This is confirmed by the fact that a space is not substantially formed between the layers when the cross section in the thickness direction of the stretchable nonwoven fabric is observed with an SEM, a microscope or the like. Further, the term “entanglement” here means a state in which the fibers are sufficiently intertwined, and a state in which the fiber layers are simply overlapped is not included in the intertwining. Whether or not they are entangled can be determined, for example, by the following method. From the state in which the fiber layers are simply overlapped, the force required to peel the fiber layers is measured. Separately, after the fiber layers are overlapped and an air-through method without heat fusion is applied thereto, the force for peeling the fiber layers is measured. If two forces are compared and a substantial difference is recognized between the two, it can be determined that they are entangled.

  In order to allow the constituent fibers of the non-elastic fiber layer 2 to enter the elastic fiber layer 1 and / or to allow the constituent fibers of the elastic fiber layer 1 to enter the non-elastic fiber layer 2, the constituent fibers and elasticity of the non-elastic fiber layer 2 are elastic. It is preferable that at least one of the non-elastic fiber and the elastic fiber is in a web state (a state where the fiber is not thermally fused) before the process of thermally fusing the constituent fibers of the fiber layer 1. From the viewpoint of allowing the constituent fibers to enter other layers, the fiber layer in the web state is preferable because the short fibers have a higher degree of freedom than the long fibers.

  In order to make the constituent fibers of the non-elastic fiber layer 2 enter the elastic fiber layer 1 and / or to make the constituent fibers of the elastic fiber layer 1 enter the non-elastic fiber layer 2, it is preferable to use an air-through method. By using the air-through method, the constituent fibers can be made to enter the opposing fiber layer, and the constituent fibers can be easily made to enter from the opposing fiber layer. Further, by using the air-through method, it becomes easy to allow the constituent fibers of the non-elastic fiber layer 2 to enter the elastic fiber layer 1 while maintaining the bulkiness of the non-elastic fiber layer 2. In particular, it is preferable to laminate an inelastic fiber layer 2 in a web state with the elastic fiber layer 1 and use the air-through method. In this case, the elastic fiber layer 1 may be heat-sealed between the constituent fibers or may not be heat-sealed. Further, as will be described later in the manufacturing method, the air-through method is performed under specific conditions, and the air permeability of the stretchable nonwoven fabric 10, particularly the air permeability of the elastic fiber layer 1, in order to improve the passage of hot air. By making the height high, the fibers can be made to penetrate more uniformly. A method other than the air-through method, for example, a method of spraying steam can also be used. In addition, a spunlace method, a needle punch method, or the like can be used. In this case, the bulk of the non-elastic fiber layer 2 is impaired, or the elastic fiber layer 1 is formed on the outer surface of the non-elastic fiber layer 2. Constituent fibers come out and the texture of the stretchable nonwoven fabric 10 tends to decrease.

In particular, when the constituent fibers of the non-elastic fiber layer 2 are entangled with the constituent fibers of the elastic fiber layer 1, it is preferable that they are entangled only by the air-through method.
In order to entangle the fibers by the air-through method, the gas spraying pressure, the spraying speed, the basis weight and thickness of the fiber layer, the transport speed of the fiber layer, and the like may be appropriately adjusted. By simply adopting the conditions for producing a normal air-through nonwoven fabric, the constituent fibers of the non-elastic fiber layer 2 and the constituent fibers of the elastic fiber layer 1 cannot be entangled. As will be described later in the manufacturing method, both constituent fibers can be entangled by performing the air-through method under specific conditions.

  In the air-through method, generally, a gas heated to a predetermined temperature is penetrated in the thickness direction of the fiber layer. In that case, fiber entanglement and fiber intersection fusion occur simultaneously. However, in the second embodiment, it is not essential to fuse the fiber intersections between the constituent fibers in each layer by the air-through method. In other words, the air-through method allows the constituent fibers of the non-elastic fiber layer 2 to enter the elastic fiber layer 1 or entangles the constituent fibers of the non-elastic fiber layer 2 with the constituent fibers of the elastic fiber layer 1, and This operation is necessary for heat-sealing the constituent fibers of the non-elastic fiber layer 2 and the constituent fibers of the elastic fiber layer 1. The direction in which the fibers enter varies depending on the direction of passage of the heated gas and the positional relationship between the non-elastic fiber layer 2 and the elastic fiber layer 1. The non-elastic fiber layer 2 is preferably an air-through nonwoven fabric in which the constituent fibers are fused at fiber intersections by an air-through method because the texture is good.

  As described above, in the stretchable nonwoven fabric 10 of the second embodiment, the elastic fiber layer 1 in which the constituent fibers maintain the fiber form is included inside the substantially inelastic air-through nonwoven fabric in the thickness direction. In addition, a part of the constituent fibers of the air-through nonwoven fabric is in a state of entering the elastic fiber layer 1 and / or a part of the constituent fibers of the elastic fiber layer 1 is entering the non-elastic fiber layer 2. In a more preferred form, some of the constituent fibers of the air-through nonwoven fabric are entangled only with the constituent fibers of the elastic fiber layer 1 by the air-through method. By including the elastic fiber layer 1 inside the air-through nonwoven fabric, the constituent fibers of the elastic fiber layer 1 are not substantially present on the outer surface of the non-elastic fiber layer 2. This is preferable from the point that the stickiness peculiar to an elastic fiber does not arise.

  The thickness of the non-elastic fiber layer 2 is preferably 1.2 to 20 times, particularly 1.5 to 5 times the thickness of the elastic fiber layer 1. On the other hand, it is preferable that the basis weight of the elastic fiber layer 1 is higher than the basis weight of the non-elastic fiber layer 2. In other words, the non-elastic fiber layer 2 is preferably thicker than the elastic fiber layer 1 and has a smaller basis weight. Since the thickness and the basis weight are in such a relationship, the non-elastic fiber layer 2 becomes thicker and bulkier than the elastic fiber layer 1. As a result, the stretchable nonwoven fabric 10 is soft and has a good texture.

  The thickness of the inelastic fiber layer 2 is preferably 0.05 to 5 mm, particularly preferably 0.1 to 1 mm. On the other hand, the thickness of the elastic fiber layer 1 is preferably smaller than the thickness of the non-elastic fiber layer 2. Specifically, the thickness of the high basis weight portion 12 is 0.05 to 2 mm, particularly 0.1 to 0. 0.5 mm is preferable. The thickness of the low basis weight portion 13 is preferably 0.03 to 1.5 mm, and particularly preferably 0.05 to 0.3 mm. The thickness can be measured by observing the cross section of the stretchable nonwoven fabric 10 with a microscope at a magnification of 50 to 200 times, obtaining the average thickness in each visual field, and obtaining the average thickness of the three visual fields.

The basis weight of the non-elastic fiber layer 2 is preferably ¹ to 60 g / m ² , particularly 5 to 15 g / m ² from the viewpoints of texture, thickness, and design properties. On the other hand, the basis weight of the elastic fiber layer 1 is preferably larger than the basis weight of the non-elastic fiber layer 2 from the viewpoints of stretch properties and residual strain, specifically 5 to 80 g / m ² , particularly 20 to 40 g. / M ² is preferable.

  The fiber diameter of the constituent fibers of the elastic fiber layer 1 is preferably 1.2 to 5 times, particularly 1.2 to 2.5 times the fiber diameter of the constituent fibers of the non-elastic fiber layer 2. In addition to this, the fiber diameter of the constituent fibers of the elastic fiber layer 1 is preferably 5 μm or more, particularly 10 μm or more, and preferably 100 μm or less, particularly 40 μm or less, from the viewpoint of air permeability and stretchability. On the other hand, the fiber diameter of the constituent fibers of the inelastic fiber layer 2 is preferably 1 to 30 μm, particularly preferably 10 to 20 μm. That is, as the constituent fiber of the non-elastic fiber layer 2, it is preferable to use a fiber having a smaller fiber diameter than that of the elastic fiber layer 1. As a result, the fusion point of the constituent fibers of the inelastic fiber layer 2 located on the surface layer of the stretchable nonwoven fabric 10 increases. The increase in the fusion point is effective in preventing the occurrence of fuzz in the stretchable nonwoven fabric 10. Furthermore, the stretchable nonwoven fabric 10 having a good touch can be obtained by using a fiber having a smaller fiber diameter than the constituent fiber of the elastic fiber layer 1 as the constituent fiber of the inelastic fiber layer 2.

  Although not shown in FIG. 5, the stretchable nonwoven fabric 10 of the second embodiment may be embossed. Embossing is performed for the purpose of further bonding the elastic fiber layer 1 and the non-elastic fiber layer 2 to further increase the bonding strength between the two fiber layers 1 and 2. Therefore, if the elastic fiber layer 1 and the non-elastic fiber layer 2 can be sufficiently joined by the air-through method, there is no need to perform embossing.

  According to the elastic nonwoven fabric 10 of 2nd Embodiment, due to the structure of the elastic fiber layer 1, in addition to the same effect as 1st Embodiment, there exists an effect similar to 3rd Embodiment mentioned later. Is done.

  When the stretchable nonwoven fabric of the present invention is used as a constituent material of an absorbent article, a stretchable nonwoven fabric having a three-layer structure as in the third embodiment is preferable because the elastic fiber layer 1 is not exposed, as will be described later. However, a stretchable nonwoven fabric having a two-layer structure as in the second embodiment can also be used as a constituent material of the absorbent article. In that case, in particular, when used in a place touching the user's skin, the non-elastic fiber layer 2 is directed toward the wearer's skin side from the viewpoint of touch and prevention of stickiness (the elastic fiber layer 1 is It is preferred to use it so that it does not face the wearer's skin.

  Next, the 2nd embodiment of the manufacturing method of the elastic nonwoven fabric of this invention used preferably for manufacture of the elastic nonwoven fabric 10 of 2nd Embodiment is described, referring FIGS. 6-9. First, similarly to the manufacturing process of the elastic fiber layer 1 in the manufacturing method of the first embodiment, the elastic fiber 1A is spun by the spinning device 22 as shown in FIG. The spun elastic fiber 1A is deposited on the conveyor 29, and an elastic fiber web 1 'including continuous filaments of elastic fibers is laminated. Further, an inelastic fiber web 2 'manufactured by a card machine (not shown) is laminated using inelastic short fibers as a raw material.

  The laminate of the two webs is sent to an air-through hot air furnace 24 where hot air treatment is performed. A part of the constituent fibers of the non-elastic fiber web 2 'enters the elastic fiber web 1' by the hot air treatment. Depending on the conditions of the hot air treatment, a part of the constituent fibers of the non-elastic fiber web 2 ′ enters the elastic fiber web 1 ′ and further entangles with the constituent fibers of the elastic fiber web 1 ′.

Conditions for allowing some of the constituent fibers of the non-elastic fiber web 2 'to enter the elastic fiber web 1' and / or allowing some of the constituent fibers of the elastic fiber web 1 'to enter the non-elastic fiber web 2'. The hot air flow rate is preferably 0.4 to 3 m / second, the temperature is 80 to 160 ° C., the conveyance speed is 5 to 200 m / minute, and the hot air treatment time is preferably 0.5 to 10 seconds. The amount of hot air here is preferably higher than the amount of hot air generally used as an air-through method, and specifically, it is preferably 1 to 2 m / sec. If a high air permeability net is used for the hot air treatment of the air-through method, the fibers are more likely to enter the air. The net used for hot air treatment and the net used for direct spinning of elastic fibers are preferably those having an air permeability of 250 to 800 cm ³ / (cm ² · s), particularly 400 to 750 cm ³ / (cm ² · s). . The above conditions are also preferred in terms of softening the fibers and allowing them to penetrate uniformly and fusing the fibers. Furthermore, the entanglement of the fibers can be achieved by setting the hot air flow rate to 3 to 5 m / sec and the spraying pressure to 0.1 to 0.3 kPa. When the air permeability of the elastic fiber web 1 'is 8 m / (kPa · s) or more, particularly 24 m / (kPa · s) or more, it is preferable because the flow of hot air is improved and the fibers can enter more uniformly. Further, there is an advantage that the fiber fusion is good, the maximum strength is high, and fuzz is prevented.

  In the hot air treatment, a part of the constituent fibers of the non-elastic fiber web 2 ′ enters the elastic fiber web 1 ′, and at the same time, the constituent fibers of the non-elastic fiber web 2 ′ and the constituent fibers of the elastic fiber web 1 ′ Heat fusion at the intersection of In this case, care should be taken so that the constituent fibers of the elastic fiber web 1 ′ do not form a film or film-fiber structure by hot air treatment. In the hot air treatment, the constituent fibers of the non-elastic fiber web 2 'are thermally fused at the intersection, and similarly, the constituent fibers of the elastic fiber web 1' are thermally fused at the intersection.

  By the hot air treatment of the air-through method, a fiber sheet 10B in which two webs are integrated (laminated) is obtained. The fiber sheet 10B is sent to an embossing device 25 including an embossing roll 26 in which embossing convex portions are regularly arranged on a peripheral surface and a receiving roll 27 arranged to face the embossing roll 26, and is subjected to heat embossing there. By hot embossing, a fiber sheet 10A in which joints (not shown) are formed in a regular pattern is obtained. The joint is preferably formed discontinuously in both the machine direction (MD direction) and the orthogonal direction (CD direction) of the fiber sheet 10A, for example.

  Next, after the fiber sheet 10A having a two-layer structure is once made into a raw fabric, the fiber sheet 10A having a two-layer structure is stretched in another line. Specifically, as shown in FIG. 7, the fiber sheet 10 </ b> A has a pair of concave and convex rolls 33 and 34 in which large diameter portions 31 and 32 and small diameter portions (not shown) are alternately formed in the axial length direction. The fiber sheet 10 </ b> A is stretched in the CD direction using the stretching device 30 including

  The stretching device 30 has a known lifting mechanism (not shown) that vertically displaces the pivot portions of one or both of the concave and convex rolls 33 and 34, and the interval between the concave and convex rolls 33 and 34 can be adjusted. . In this manufacturing method, each of the concavo-convex rolls 33, 34 is loosely inserted between the large-diameter portion 32 of the other concavo-convex roll 34 and the large-diameter portion of the other concavo-convex roll 34. 32 is loosely inserted between the large-diameter portions 31 of one concave-convex roll 33, and the fiber sheet 10A is inserted between the concave-convex rolls 33, 34 in that state, and the fiber sheet 10A is stretched in the CD direction. .

In the stretching device 30, both the uneven rolls 33 and 34 may be driven (co-rotation), or only one of the uneven rolls 33 or 34 may be driven (accompanying rotation). In this stretching step, it is preferable to match the position in the CD direction of the joint portion in the fiber sheet 10 </ b> A with the position of the large diameter portions 31 and 32 of the uneven rolls 33 and 34.
As a result, according to this manufacturing method, the elastic nonwoven fabric 10 of 2nd Embodiment can be manufactured efficiently.

  By the stretching process, the thickness of the fiber sheet 10A is preferably increased 1.1 times to 4 times, particularly 1.3 times to 3 times before and after the stretching process. As a result, the fibers of the inelastic fiber layer 2 are plastically deformed and stretched, and the fibers become thin. At the same time, the non-elastic fiber layer 2 becomes more bulky, and the touch and cushioning properties are improved. If the thickness of the fiber sheet 10A before being stretched is thin, there is an advantage that the space for transporting and storing the roll sheet of the fiber sheet 10A can be reduced.

  Furthermore, it is preferable that the bending rigidity of the fiber sheet 10 </ b> A is changed to 30 to 80%, particularly 40 to 70% as compared with that before the drawing process by the drawing process. As a result, a soft nonwoven fabric with good drapability can be obtained. Moreover, since the bending rigidity of 10 A of fiber sheets before extending | stretching process is high, since it becomes difficult for a wrinkle to enter into the fiber sheet 10A by a conveyance line, it is preferable. In addition, the fiber sheet 10A is not wrinkled even during the drawing process, and is easy to process, which is preferable.

  The thickness and bending rigidity of the fiber sheet 10A before and after the stretching process are the elongation of the fiber used for the inelastic fiber layer 2, the embossing pattern of the embossing roll, the pitch of the uneven rolls 33 and 34, the thickness of the tip, and the amount of meshing Can be controlled by.

  The fiber sheet 10A delivered from the stretching device 30 is released from the stretched state in the CD direction. That is, the elongation is eased. As a result, the stretchability in the CD direction appears in the fiber sheet 10A, and the fiber sheet 10A contracts in the width direction. Thereby, the target elastic nonwoven fabric 10 is obtained. When the stretched state is released, the stretched state may be completely released, or the stretched state may be released in a state where a certain stretched state is maintained as long as stretchability is exhibited.

  In the manufacturing method of the second embodiment, a second stretching device 30A for stretching in the MD direction is further provided on the downstream side of the stretching device (hereinafter also referred to as “first stretching device”) 30 for stretching in the CD direction. Can be provided. As shown in FIGS. 8 and 9, the second stretching device 30 </ b> A further stretches the stretchable nonwoven fabric 10 of the second embodiment stretched in the CD direction by the first stretching device 30 in the MD direction. 30 A of 2nd extending | stretching apparatus consists of the tooth gap roll 38 and 38 which makes a pair by two. The tooth groove roll 38 has tooth grooves extending in the axial direction and meshing with each other on the peripheral surface portion thereof.

  According to the 2nd extending | stretching apparatus 30A, similarly to extending | stretching to CD direction by the 1st extending | stretching apparatus 30 mentioned above, between a pair of tooth space rolls 38 along the rotation direction of the tooth space roll 38 of 2nd Embodiment. The stretchable nonwoven fabric 10 can be stretched in the MD direction by biting the stretchable nonwoven fabric 10. And by releasing the stretched state, the high basis weight portion and the low basis weight portion are alternately arranged not only in the CD direction but also in the MD direction in the elastic fiber layer 1 (in other words, the high basis weight portion and A stretchable nonwoven fabric 10C in which the low basis weight portions are arranged in a lattice pattern in the plane direction is obtained.

  Next, the elastic nonwoven fabric of 3rd Embodiment is demonstrated. In the third embodiment, as shown in FIG. 10, the same or different substantially inelastic non-elastic fiber layers 2 and 3 are laminated on both surfaces of the elastic fiber layer 1. The two inelastic fiber layers 2 and 3 may be the same or different in material, basis weight, thickness, and the like of the constituent fibers.

  The stretchable nonwoven fabric of the third embodiment can be produced, for example, by the following method. First, an inelastic short fiber is used as a raw material, and one inelastic fiber web is manufactured by a card machine and continuously conveyed in one direction. On top of this, the spun elastic fibers 1A are directly deposited to form the elastic fiber layer web 1 '. Prior to depositing the elastic fiber layer, the non-elastic fiber web is preferably temporarily fused or entangled by heat treatment. By doing in this way, the freedom degree of elastic fiber 1A becomes high, and it becomes easier to make a mutual fiber enter by wind etc. Examples of temporary fusing by heat treatment include a heat roll method, a pressure calender roll method, a steam method, and an air-through method, and examples of temporary entanglement include a needle punch method and a water jet method. In particular, use of a heat roll and an air-through method is preferable in that the texture of the nonwoven fabric is not impaired and the facility space can be reduced.

The non-elastic fiber web is preferably not directly wound after temporary fusing or temporary entanglement, and the elastic fibers 1A are directly deposited thereon in-line. The reason is that once wound up, the inelastic fiber web may be crushed by the winding pressure. The purpose of temporary fusing or entanglement is to prevent the non-elastic fiber web from being blown away by wind or the like when the elastic fiber 1A is directly melt-spun and deposited on the non-elastic fiber web.
The process after laminating | stacking elastic fiber layer web 1 'on a non-elastic fiber web is the same as that of the manufacturing method of the elastic nonwoven fabric of the 2nd embodiment shown in FIGS.

  The elastic nonwoven fabric 10 of 3rd Embodiment can be used for various uses, such as a surgical garment and a cleaning sheet, from the point of the favorable texture, fuzz prevention property, a stretching property, and air permeability. In particular, it is preferably used as a constituent material of absorbent articles such as sanitary napkins and disposable diapers. For example, it can be used as a sheet for providing elastic stretchability to a sheet constituting the outer surface of a disposable diaper, a waistline part, a waist part, a leg periphery part, or the like. The example which used the elastic nonwoven fabric 10 of 3rd Embodiment for the constituent material of a disposable diaper is explained in full detail later. Moreover, the elastic nonwoven fabric 10 of 3rd Embodiment can be used as a sheet | seat etc. which form the elastic wing of a sanitary napkin, and even if it is other site | parts, it is used for the site | parts etc. which want to provide elasticity. Can do.

The basis weight and thickness of the stretchable nonwoven fabric of the third embodiment can be appropriately adjusted according to the specific application. For example, when used as a constituent material of an absorbent article, it is desirable that the basis weight is about ²⁰ to 160 g / m ² and the thickness is about 0.1 to 5 mm. The stretchable nonwoven fabric of the third embodiment is flexible and has high air permeability due to the fact that the constituent fibers of the elastic fiber layer 1 maintain the fiber form. Regarding the bending stiffness which is a measure of flexibility, the stretchable nonwoven fabric of the third embodiment preferably has a bending stiffness value as low as 10 g / 30 mm or less. The air permeability is preferably 16 m / (kPa · s) or more. The elongation is preferably 100% or more.

  The bending stiffness is measured in accordance with JIS L1096, and is obtained as an average value when bent in the flow direction and in a direction perpendicular to the flow direction under the conditions of a push amount by the handle ohmmeter: 8 mm and a slit width: 10 mm. The air permeability is obtained as an inverse of the air resistance measured by AUTOMATIC AIR-PERMEABILITY TESTER KES-F8-AP1 manufactured by Kato Tech Co., Ltd.

In the stretchable nonwoven fabric of the present invention, the form comprising the single-layer structure of the elastic fiber layer 1 as in the first embodiment, and the elastic fiber layer 1 and the non-elastic fiber layer as in the second and third embodiments. In any of the forms composed of a laminated (two or more layers) structure, the plurality of high basis weight portions 12 may have different widths depending on their positions along the CD direction, and the plurality of low basis weight portions 13 May have different widths depending on their positions.
For example, in the form shown in FIG. 11, the high basis weight portion 12 may include the high basis weight portions 12 having three kinds of widths, that is, the high basis weight portions 12A, 12B, and 12C, in the order of width. In addition, the low basis weight portion 13 may be mixed with three types of low basis weight portions 13 of the low basis weight portions 13A, 13B, and 13C in the order of width.

Next, as a specific application of the stretchable nonwoven fabric of the present invention, an example in which the stretchable nonwoven fabric 10 of the third embodiment is applied to a pants-type disposable diaper will be described. In the disposable diaper of the present embodiment, elastic stretchability is imparted to the waistline portion D by using the stretchable nonwoven fabric 10 of the third embodiment for the outer layer sheet 112 described later.
The pants-type disposable diaper according to the present embodiment includes an absorbent main body including an absorbent core and an outer packaging material joined to the non-skin contact surface side of the absorbent main body. Both side edges of the side portions are joined together to form a pair of side seal portions, a waist opening, and a pair of leg openings. This diaper has the following characteristics.

(A) The outer packaging material has a structure in which an outer layer sheet made of a stretchable sheet and an inner layer sheet made of a non-stretchable sheet are laminated, and the outer layer sheet and the inner layer sheet have the side seal portion and the It is not joined in the whole area or most part of a part except a peripheral part of a waist opening part and the said leg opening part.
(B) The absorbent main body and the inner layer sheet of the outer packaging material are joined by a main body joining portion.
(C) In a state where the side seal portion is separated and the outer packaging material is deployed, the substantial width of the inner layer sheet is wider than the width of the outer layer sheet in a contracted state.
The pants-type disposable diaper having the above features will be described below with reference to the drawings.

  As shown in FIGS. 12 to 15, the diaper 101 includes a liquid-permeable top sheet 102, a liquid-impermeable or water-repellent back sheet 103 and a liquid-retaining absorption disposed between the sheets 102 and 103. A substantially vertically long absorbent main body 110 having a conductive core 104 and an outer packaging material 111 bonded to the back sheet 103 side (non-skin contact surface side) of the absorbent main body 110.

  The outer packaging material 111 has an hourglass shape in which both side edges are bound inward in the central portion in the longitudinal direction, and defines the outline of the diaper. The outer packaging material 111 is divided in the longitudinal direction into an abdominal side A disposed on the wearer's abdomen, a back side B disposed on the dorsal side, and a crotch C positioned therebetween. The abdominal side portion A and the back side portion B correspond to the longitudinal front and rear end portions of the outer packaging material 111, and the crotch portion C corresponds to the longitudinal center portion of the outer packaging material 111. In the outer packaging material 111, both side edges A1 and A2 of the ventral side A and both side edges B1 and B2 of the back side B are joined together, and the disposable diaper 101 has a waist opening 105 and a pair of leg openings. 106 is formed. By this joining, a pair of side seal portions S, S are formed on the left and right side edges of the disposable diaper 101 to form a pants shape. For these bondings, for example, heat sealing, high frequency sealing, ultrasonic sealing, or the like is used.

  The top sheet 102, the back sheet 103, and the absorbent core 104 are each rectangular and integrated to form a vertically long absorbent main body 110. As the top sheet 102, the back sheet 103, and the absorbent core 104, the same ones conventionally used for this type of diaper can be used. For example, the absorbent core 104 may be made of superabsorbent polymer particles and fiber material and covered with tissue paper (not shown).

  As shown in FIG. 16, the absorbent core 104 includes an hourglass-shaped central absorbent body 141 and a pair of side absorbent bodies 142 and 142 provided symmetrically on both sides of the central absorbent body 141. The central absorbent body 141 and the pair of side absorbent bodies 142, 142 are separated from each other at least at the crotch portion. One side in the longitudinal direction and the other side in the longitudinal direction of the side absorbent body 142 are connected to each other at one side in the longitudinal direction (abdominal side) and the other side in the longitudinal direction (back side) of the central absorbent body 141, respectively. Therefore, the cut-out portions 143 and 143 are formed between the central absorbent body 141 and the pair of side absorbent bodies 142 and 142, respectively.

  One part in the longitudinal direction, the central part in the longitudinal direction, and the other part in the longitudinal direction are each region when the absorbent core 104 is divided into three regions so as to be divided into approximately three equal parts in the longitudinal direction. When the absorptive core 104 has the separation part 143, the both-sides edge part of the absorptive core 104 will stand up easily. Further, when the absorbent core 104 is pressed in the width direction, the entire width of the absorbent core 104 is narrowed, so that the shrinkage in the width direction of the outer packaging material 111 is difficult to be inhibited. Note that the shape of the absorbent core 104 in plan view is not limited to the shape shown in FIG. 16. For example, the side absorbent body 142 is connected to the central absorbent body 141 only in one of the longitudinal direction one part or the longitudinal direction other part. The side absorber 142 may have a shape in which the side absorber 142 is not connected to the central absorber 141 (separated) or a shape that does not have the separation portion 143 (none of which is shown).

  Side cuffs 108 and 108 made of a liquid-resistant or water-repellent and breathable material are formed on both the left and right sides of the absorbent main body 110 in the longitudinal direction, as shown in FIGS. . In the vicinity of the free end of each side cuff 108, a side cuff elastic member 181 is disposed in an extended state. Accordingly, when the disposable diaper 101 assembled as shown in FIG. 12 is worn, the side cuffs 108 stand up due to contraction of the side cuff elastic members 181, so that the absorbent main body 110 extends in the width direction. Liquid outflow is prevented. As shown in FIGS. 14 and 15, the sheet material 182 for forming the side cuffs 108 and 108 has a predetermined width portion 182 </ b> S outside the width direction of the absorbent main body 110 in the diaper state. It is wound down to the skin contact surface side and fixed between the absorbent core 104 and the back sheet 103.

  The outer packaging material 111 has a structure in which an outer layer sheet 112 made of the stretchable nonwoven fabric of the present invention and an inner layer sheet 113 made of a non-stretchable sheet are laminated. The outer layer sheet 112 forms the outer surface of the diaper, and the inner layer sheet 113 is disposed on the inner surface side of the outer layer sheet 112. The stretchable nonwoven fabric that forms the outer layer sheet 112 only needs to have stretchability in at least the diaper width direction (left-right direction in FIG. 13) when the diaper is in an unfolded state. The non-stretchable sheet forming the inner layer sheet 113 does not have stretchability at least in the diaper width direction when the diaper is in an unfolded state.

  The outer layer sheet 112 can extend larger in the diaper width direction than in the diaper longitudinal direction (vertical direction in FIG. 13). More specifically, in the diaper width direction, it stretches greatly and contracts after stretching (maximum elongation of 100% or more and elongation recovery rate of 70% or more), but in the diaper longitudinal direction, it stretches only slightly (for example, , Maximum elongation of 50% or less).

  As the non-stretch sheet, a nonwoven fabric, a laminated material of a nonwoven fabric and a resin film, a porous film, and the like are preferable. The non-stretch sheet is preferably formed from a nonwoven fabric made of thermoplastic fibers from the viewpoint of improving air permeability and texture, and is formed from a water-repellent nonwoven fabric from the viewpoint of preventing excrement leakage. Are preferred.

  In the diaper 101, as shown in FIG.14 and FIG.15, between the outer layer sheet | seat 112 and the inner layer sheet | seat 113 in each of the abdominal side part A and the back side part B in side seal part A1, A2, B1, B2. Are bonded to each other by heat sealing, high frequency sealing or ultrasonic sealing, and an adhesive such as a hot melt adhesive is used at the peripheral edge 150 of the waist opening 105 and the peripheral edge 160 of each of the pair of leg openings 106. 152 and 162 are joined together. And between the outer layer sheet | seat 112 and the inner layer sheet | seat 113 in each of the ventral | abdominal part A and the back | dorsal part B is not joined in most of the parts except these parts.

  Specifically, between the outer layer sheet 112 and the inner layer sheet 113, in addition to the side seal portions A1, A2, B1, and B2, the peripheral edge portion 150 of the waist opening portion 105, and the peripheral edge portions 160 of the pair of leg opening portions 106, respectively. And it is joined in the diaper width direction center part of each of the abdominal part A and the back part B, and it is not joined in parts other than those.

  In this way, in a wide range in the ventral side A and the back side B, a configuration in which the outer layer sheet 112 and the inner layer sheet 113 are not joined together minimizes a portion where the outer packaging material 111 is hardened by the adhesive. The portion of the outer surface of the diaper and the inner surface of the outer packaging material 111 that is not covered with the absorbent main body 110 can be made soft and soft to the touch. Moreover, since the air permeability of the outer packaging material 111 is maintained well, it is possible to provide a diaper that is less likely to be stuffy. Furthermore, since the outer peripheral sheet 112 and the inner layer sheet 113 are joined to each other at the peripheral edge portions 150 and 160 of the waist opening 105 and the pair of leg openings 106, the waist portion D has a stretchable outer packaging material. With 111, an appropriate fit can be obtained.

  A plurality of waist elastic members 151 and 151 are arranged along the opening peripheral edge of the waist opening 105 at the waist E in each of the ventral side A and the back side B. The waist portion E refers to a region from the peripheral edge of the waist opening 105 to a position spaced 30 mm downward, for example, as shown in FIG. 17, the position of the peripheral edge of the ventral waist opening 105 and the back side. In the case where the position of the peripheral edge of the waist opening 105 is deviated, the range of the waist E is determined on the assumption that there is no region extending deviated. These waist elastic members 151 and 151 are fixed in an extended state between the outer layer sheet 112 and the inner layer sheet 113 via an adhesive 152.

  In addition, leg elastic members 161a and 161b are also provided along the peripheral edge of each opening on the peripheral edge 160 and 160 of the leg opening extending over the ventral side A, the crotch C and the back side B. It is arranged. These leg elastic members 161 a and 161 b are fixed in an extended state between the outer layer sheet 112 and the inner layer sheet 113 via an adhesive 162. As the waist elastic member 151 and the leg elastic members 161a and 161b, elastic materials such as natural rubber, polyurethane resin, urethane foam resin, and hot melt elastic member are made into a thread shape (thread rubber) or a belt shape (flat surface), respectively. Those formed into (rubber) are preferably used.

  In this way, thread-like or belt-like elastic members 151, 161a, 161b are sandwiched between the outer layer sheet 112 and the inner layer sheet 113 at the peripheral edge portions 150, 160 of the waist opening 105 and the pair of leg openings 106, respectively. By fixing to the state, the fit of these parts can be enhanced without being restricted by the expansion / contraction characteristics of the outer packaging material 111.

  In addition, since the thread-like or belt-like elastic members 151, 161a, 161b can be fixed in a state of being sandwiched between the outer layer sheet 112 and the inner layer sheet 113, such an elastic member is fixed to an outer packaging material made of a single sheet. Compared to the case, the elastic member can also prevent the wearer from feeling uncomfortable or deteriorating the appearance.

  In the diaper 101, the width of the region where the outer layer sheet 112 and the inner layer sheet 113 are joined at the peripheral edge 150 of the waist opening 105 is the width of the waist opening for each of the ventral side A and the back side B. It is preferably within 70 mm from the peripheral edges 105a and 105b, and more preferably within 60 mm. The width of the region where the outer layer sheet 112 and the inner layer sheet 113 are joined to each other at the peripheral edge 160 of the leg opening 106 is the leg opening at each of the ventral side A, the crotch C and the back side B. It is preferably within 50 mm from the peripheral edge of 106, and more preferably within 30 mm.

  In addition, in the diaper width direction in each of the ventral side A and the back side B, the total length (L1 + L2) of the portion where the outer layer sheet 112 and the inner layer sheet 113 are not joined is determined by the left and right side seal portions A1, The length La (Lb) between A2 is preferably 60% or more, more preferably 70% or more, and further preferably 75% or more.

  The area of the portion where the outer layer sheet 112 and the inner layer sheet 113 are not joined to each other in the ventral side A and the back side B is 60 to 100 with respect to the areas of the ventral side A and the back side B, respectively. %, And more preferably 70 to 100%. Those satisfying this numerical value are referred to as “whole area or most part”.

  The dimensions, ratios, etc. of each part described in this specification are as follows. The diaper is in an unfolded state as shown in FIG. 13, and the contraction force by the elastic members of the waist opening and the leg opening is released. The value measured in the state of not acting) or based on it.

  In the diaper 101, between the outer layer sheet 112 and the inner layer sheet 113 in the crotch part C, the peripheral part 160 of the leg opening part and the diaper width direction center part of the crotch part C via the adhesive 162 and the joint part 114 Although it is joined, it is not joined in other parts. In the diaper 101, as shown in FIG. 13, the leg elastic member 161 for imparting stretchability to the peripheral edge 160 of the leg opening is formed from the peripheral edge 160 of the leg opening to the center of the crotch C in the width direction. The portion where the leg elastic member 161 for imparting stretchability to the leg opening in the circumferential direction is arranged in this manner is included in the peripheral edge 160 of the leg opening.

  In the diaper 101, since the outer layer sheet 112 and the inner layer sheet 113 are joined at the central part in the diaper width direction of each of the abdominal part A, the back part B, and the crotch part C, and before the diaper is mounted. The inside appearance can be further improved. Further, when a disposal tape (not shown) is provided on the outer surface of the outer packaging material 111, the disposal tape can be firmly fixed by fixing the disposal tape to the central part in the diaper width direction. The disposal tape is a tape that holds the diaper in a rolled state, and various conventionally known tapes can be used.

  Since the outer layer sheet 112 and the inner layer sheet 113 are joined at the central part of the diaper width direction of each of the abdominal side part A, the back side part B, and the crotch part C, the back sheet 103 has patterns, characters, and the like. When symbols such as symbols are provided, the symbols can be clearly seen from the outer surface side of the diaper.

  In the diaper 101, as shown in FIGS. 13 and 14, the outer layer sheet 112 constituting the outer surface side of the outer packaging material 111 sandwiches and fixes the waist elastic members 151 and 51 by the outer layer sheet 112 and the inner layer sheet 113. The portions 112a and 112b of the outer layer sheet 112 that extend further than the inner layer sheet 113 are folded back to the absorbent main body 110 side. As for the absorptive main body 110, the skin contact surface side in the longitudinal direction both ends is covered with the folded-back portions (folded portions) 112a and 112b of the outer layer sheet 112. The folded portions 112a and 112b of the outer layer sheet 112 have portions that overlap with both ends in the longitudinal direction of the absorbent main body 110 bonded to each other through an adhesive (not shown) over substantially the entire width of the absorbent main body 110, Thereby, the longitudinal direction both ends of the absorptive main body 110 are fixed to the outer packaging material 111. By forming the folded portions 112a and 112b, the front and rear ends of the absorbent main body 110 are prevented from coming into direct contact with the wearer, and the water absorbent polymer of the absorbent core 104 from the front and rear ends of the absorbent main body 110 is prevented. Leakage can be prevented.

  Next, the waistline portion D will be described. As shown in FIG. 13, the waistline portion D refers to a region from below the waist portion E to the upper end of the leg opening 106. As shown in FIG. 13, the waistline portion D is further divided in the longitudinal direction into an upper waistline portion D1 and a lower waistline portion below the upper waistline portion D1. The upper waistline portion D1 is preferably located in a region that abuts a portion (hereinafter also referred to as “iliac region”) from the wearer's iliac crest to the upper anterior iliac spine when the diaper 101 is worn. The iliac crest and superior anterior iliac spine are anatomical terms. The iliac crest is a part indicated by reference numeral Q1 in FIG. 18, and the upper anterior iliac spine is a part indicated by reference numeral Q2 in FIG.

Conventionally, in order to prevent slippage during wearing of a pant-type diaper, especially when the diaper is for an infant, the tightening pressure by the waist part E is increased, and the pant-type by the tightening pressure by the waist part E It has been considered effective to bring the diaper into close contact with the wearer's body.
However, in order to effectively prevent slipping during wearing of the pants-type diaper, the tightening pressure of the diaper corresponding to the wearer's iliac region is conventionally increased rather than the tightening pressure of the waist E. It has been found that it is effective to increase it. The reason for this is that the wearer (especially infants) overhangs the abdomen as a physical feature, so if the tightening pressure of the waist E that contacts the overhanging abdomen is increased, the tightening pressure is high. This is because the waist part E is gradually narrowed down and the waist part E is shifted down to a site where the abdominal circumference becomes thinner.

FIG. 19 shows a state in which the baby's body is regarded as a cone. In the figure, θ represents an angle formed by a perpendicular to the tangent at the waist (point A) and a horizontal line toward the center of the body. F indicates the clamping force of the elastic member, P indicates the frictional force resulting from the clamping force F, f1 indicates the displacement drop force caused by the clamping force F, and f2 indicates the normal resistance. Here, since f1 = Fsinθ and P = νN = νf2 = νFcosθ (ν represents a friction coefficient), the “slip-off force Z” directed downward at the point A is represented by the following equation.
Z = f1−P = Fsinθ−νFcosθ = F (sinθ−νcosθ)
From this equation, it can be understood that when the waist portion E is in a state in which a slip-off occurs, the slip-off force increases as the tightening force F increases.

  A portion (iliac region) from the wearer's iliac crest to the upper anterior iliac spine has a certain width, and the upper waistline portion D1 of the diaper 1 is fixed to the iliac region within the range of the width. The diaper 1 can be effectively prevented from falling off. From this viewpoint, in the diaper 1 of the present embodiment, the width of the upper waistline portion D1 (that is, the length of the upper waistline portion D1 along the longitudinal direction of the diaper 1) is set to 12 to 35 mm. When this width is 20 to 35 mm, particularly 25 to 30 mm, the diaper 1 can be prevented from slipping off more effectively, and the appearance of the diaper 1 in the wearing state and the wearing operation of the diaper 1 (easy to wear) Etc.) can be further improved.

  In the state where the diaper 1 is worn, the size of the diaper 1 and the wearer are determined so that the upper waistline portion D1 abuts on a portion (iliac region) from the wearer's iliac crest to the upper anterior iliac spine. The relationship with the physique is important. For example, when an infant who is a main wear target person of a pants-type diaper is considered, in the unfolded state of the diaper 1, the center position (center position along the longitudinal direction of the diaper 1) of the upper waistline portion D1 of the abdominal side A and the diaper The distance K1 (refer to FIG. 13) between the longitudinal center line CL of 1 and the central position of the upper waistline portion D1 of the back side portion B (the longitudinal direction of the diaper 1) when the diaper 1 is unfolded. The distance between the upper waistline D1 and the iliac region of the wearer can be successfully abutted by setting the distance K2 (see FIG. 13) between the longitudinal center line CL of the diaper 1 to 180 to 230 mm. Can be made.

This value is determined by carrying out body measurements of about 350 infants who are the main wearees of pants-type diapers. Specifically, as shown in FIG. 20, this value is obtained by defining the abdominal lateral center point at the horizontal position height of the upper anterior iliac spine as “the upper anterior iliac spine height front center” The center point of the dorsal side at the horizontal position of the iliac spine is defined as the “upper center of the upper anterior iliac spine” and the upper anterior iliac bone via the crotch from the center of the upper anterior iliac spine. The length to the center after the height of the spine is defined as the “upper and lower length of the superior anterior iliac spine”, and the numerical value obtained by adding the necessary length considering the thickness of the diaper material, etc. It is a bisection. By setting the distances K1 and K2 to 185 to 220 mm, particularly 195 to 215 mm, the upper waistline portion D1 can be brought into more successful contact with the wearer's iliac region.
In the case of an adult diaper, the upper waistline D1 can be brought into more successful contact with the wearer's iliac region by setting the distances K1 and K2 to 300 to 350 mm, particularly 305 to 335 mm.

In addition, in the case where the position of the peripheral edge of the waist opening 105 on the ventral side and the position of the peripheral edge of the waist opening 105 on the back side are not substantially deviated from the longitudinal center line CL of the diaper 1. , Refers to a straight line along the diaper width direction that passes through the midpoint in the longitudinal direction of the diaper 1 in the unfolded state.
On the other hand, as shown in FIG. 17, for example, when the position of the peripheral edge of the waist opening 105 on the ventral side and the position of the peripheral edge of the waist opening 105 on the back side are shifted, A diaper longitudinal center line CL is determined on the assumption that no region exists.

  In the diaper 1 according to the present embodiment, the diaper 1 is fixed to the wearer's body mainly by the tightening force of the upper waistline D1. In other words, unlike the conventional pants-type diaper, the tightening force by the waist portion E is not the main means for fixing the diaper 1 to the wearer's body in the diaper 1 of the present embodiment. On the contrary, if the fastening force of the waist part E is increased, the diaper 1 will be displaced.

  When the diaper 1 is worn, the lower waistline portion D2 is preferably in contact with the lower region (lower abdomen) of the wearer's iliac region. The width of the lower waistline portion D2 (that is, the length of the lower waistline portion D2 along the longitudinal direction of the diaper 1) is preferably 40 to 70 mm, particularly 45 to 65 mm.

  As shown in FIGS. 14 and 15, the absorbent main body 110 is bonded to the inner layer sheet 113 of the outer packaging material 111 by the main body bonding portion 115 only in the central portion in the width direction, as shown in FIGS. 14 and 15. . Since the expansion and contraction of the outer packaging material 111 is less likely to be hindered by the joining of the absorbent main body 110, a good fit is obtained for the waistline portion D. The width W1 of the joint portion 114 between the outer layer sheet 112 and the inner layer sheet 113 in the central portion of the outer packaging material 111 in the diaper width direction is equal to the width W of the absorbent main body 110 in each of the ventral portion A and the back portion B. It is preferably 0 to 40%, and more preferably 0 to 30%. When the width W1 of the joint 114 exceeds 40% of the width W of the absorbent main body 110, the stretchability is inhibited.

  The main body bonding portion 115 is provided at a central portion in the diaper width direction. The width W2 of the main body bonding portion 115 is preferably 70% or more of the width W on the non-skin contact surface side of the absorbent main body 110 in each of the ventral side A and the back side B, and is 75% or more. More preferably. When the width W2 of the main body bonding portion 115 is 70% or more of the width W of the absorbent main body 110, the absorbent main body 110 is hardly peeled or broken during mounting. The main body joint 115 may be spaced apart in the diaper width direction.

  In a state where the side seal portion S is separated and the outer packaging material 111 is deployed, the substantial width of the inner layer sheet 113 is wider than the width of the outer layer sheet 112 in a contracted state. That is, in the state where the outer packaging material 111 is unfolded, the outer layer sheet 112 is in a contracted state due to its contraction force, but the inner layer sheet 113 is made of a non-stretchable sheet, so that the width is hardly reduced. Therefore, the inner layer sheet 113 is loosened in the width direction with respect to the outer layer sheet 112. Such a slackened inner layer sheet 113 is virtually separated from the outer layer sheet 112, and the width of the inner layer sheet 113 when the slackness of the inner layer sheet 113 is eliminated is defined as “substantial width of the inner layer sheet 113”.

  The substantial width of the inner layer sheet 113 is preferably 1.3 to 4.0 times, more preferably 1.5 to 3.0 times the width of the outer layer sheet 112 in a contracted state.

  In the diaper 101 configured as described above, in the state where the side seal portion S is separated and the outer packaging material 111 is deployed, the substantial width of the inner layer sheet 113 is larger than the width of the outer layer sheet 112 in a contracted state. It is getting wider. Therefore, since the outer layer sheet 112 of the outer packaging material 111 is formed from an elastic sheet, the appearance and fit of the diaper when worn is good. In addition, since the inner layer sheet 113 of the outer packaging material 111 is formed of a non-stretchable sheet, even when the outer packaging material 111 extends in the width direction during use, the inner layer sheet 113 is loosened and the absorbent main body 110 from the outer packaging material 111 is absorbed. Problems such as peeling off and tearing of the outer packaging material 111 hardly occur. In addition, the skin contact surface side of the outer packaging material 111 has good tactile sensation and texture, and is excellent in softness.

  In the diaper 101, since the outer layer sheet 112 and the inner layer sheet 113 made of a non-stretchable sheet are hardly adhered, the stretchability of the outer packaging material 111 is good without being affected by the non-stretchable absorbent main body 110. It is. Even when the outer layer sheet 112 of the outer packaging material 111 is released from the stretched state, the absorbent main body 110 is excellent in appearance without contracting, and the absorbent performance of the absorbent main body 110 can be maintained. Therefore, even if the width W2 of the main body joint 115 is set wide, the stretchability in the width direction of the outer packaging material 111 is not hindered.

  The stretchable nonwoven fabric of the present invention is not limited to the above embodiment. For example, the stretchable nonwoven fabric of the present invention may have a structure of four or more layers. In that case, the form in which the elastic fiber layer and the non-elastic fiber layer are alternately laminated is general, but the form includes the form in which the elastic fiber layer is laminated adjacently and the form in which the non-elastic fiber layer is laminated adjacently. But you can.

  The manufacturing method of the elastic nonwoven fabric of this invention is not restrict | limited to the said embodiment. For example, in the method shown in FIG. 9, the fiber sheet 10 </ b> A is stretched without being sandwiched between the large diameter portion of one uneven roll and the small diameter portion of the other uneven roll. Stretching can also be performed in a state where the fiber sheet 10A is sandwiched between the large diameter portion and the small diameter portion by narrowing the interval between the small diameter portion. That is, the fiber sheet 10A can be stretched with the large diameter part and the small diameter part bottomed out. In addition, the stretching step can be performed by the method described in JP-A-6-133998.

In the manufacturing method of the second embodiment, the means for joining the elastic fiber layer 1 and the non-elastic fiber layer 2 is not limited to the air-through method. For example, an adhesive, embossing (heat or ultrasonic waves), heat Examples thereof include rolls and spun laces (the water-inelastic fiber layer 2 before being formed into a nonwoven fabric is overlapped on the elastic fiber layer 1 and water jetting is performed).
In addition, when the constituent fibers of the elastic fiber layer are in a molten or semi-molten state immediately after spinning, the constituent fibers of the elastic fiber layer in the molten or semi-molten state are introduced onto the non-elastic fiber layer web and melted. The elastic fiber layer 1 and the non-elastic fiber layer 2 can be joined by utilizing the solidified bonding force or adhesive force of the constituent fibers of the elastic fiber layer in the state or semi-molten state.

  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.

About the following Example 1 and Comparative Example 1, the width shrinkage at the time of expansion was evaluated by the following “Method for measuring width shrinkage at the time of elongation”. The evaluation results are shown in [Table 1] below. In [Table 1], the value indicated by% in [] is the percentage of the minimum width under the above conditions based on the minimum width before expansion.
<Measurement method of width shrinkage during expansion>
The stretchable nonwoven fabric is cut into rectangular test pieces with a size of 250 mm in the MD direction and 150 mm in the CD direction. The cut specimen is mounted on a testing machine (Orientec Co., Ltd .: Tensilon RTC1210A). The distance between chucks is 200 mm. When the specimen is stretched in the MD direction at a speed of 300 mm / min and stretched to 250 mm (stretched 1.25 times), stretched to 300 mm (stretched 1.5 times) Then, the minimum width (width in the CD direction) of the test piece when the extension force is released is measured.

[Example 1]
The stretchable nonwoven fabric of the first embodiment was manufactured by a melt blown method using 100% SEPS resin as a raw material. In this test piece, a 15 mm width low basis weight portion 13, a 40 mm width high basis weight portion 12, a 40 mm width low basis weight portion 13, a 40 mm width high basis weight portion 12, a 15 mm width low in the CD direction. The high basis weight portion 12 and the low basis weight portion 13 are arranged in the order of the basis weight portion 13. The basis weight of the high basis weight portion 12 is 20.8 g / m ^2, the basis weight of Teitsuboryou portion 13 is 15.4 g / m ^2.
[Comparative Example 1]
Compared with Example 1, there is no high basic weight part 12 and the low basic weight part 13, and the basic weight of the whole elastic nonwoven fabric is uniform in the whole surface, and is 17.4 g / m < ² >. The rest is the same as in the first embodiment.

  FIG. 21 shows the stretch characteristics obtained by performing the following “Method for measuring stretch characteristics in MD direction” for each of Example 1 and Comparative Example 1. Moreover, the expansion / contraction characteristic obtained by performing the following "measurement method of the expansion / contraction characteristic of MD direction" about each of following Example 2 and Comparative Example 2 is shown in FIG.

<Measuring method of MD direction stretch characteristics>
The stretchable nonwoven fabric is cut into rectangular test pieces with a size of 150 mm in the MD direction and 10 mm in the CD direction. The cut specimen is mounted on a testing machine (Orientec Co., Ltd .: Tensilon RTC1210A). The distance between chucks is 100 mm. The test piece is extended in the MD direction at a speed of 300 mm / min until the distance between chucks reaches 200 mm (that is, until the elongation reaches 100%), and then the extension force is released. Measures the load in the extension process and the release process of the extension force in increments of approximately 10%.

[Example 2]
The elastic nonwoven fabric of 3rd Embodiment was manufactured. In the third embodiment, the elastic fiber layer 1 is formed by a melt blown method using 100% SEPS resin as a raw material. The non-elastic fiber layers provided on both surfaces of the elastic fiber layer are formed by an air-through method using PET / PE fibers as a raw material. In the elastic fiber layer in the test piece, the high basis weight portion 12 and the low basis weight portion 13 are arranged in the order of the 40 mm width low basis weight portion 13 and the 40 mm width high basis weight portion 12. The basis weight of the high basis weight portion 12, 40.2 g / m ² throughout the elastic fiber layer and inelastic fibrous layer, 19.5 g / m ² by the elastic fiber layer, the non-elastic fiber layer with 20.7 g / m ² is there. The basis weight of Teitsuboryou portion 13, 32.0 g / m ² throughout the stretchable nonwoven fabric, 10.4 g / m ² by the elastic fiber layer, an inelastic fibrous layer is 21.6 g / m ^2.

[Comparative Example 2]
Compared with Example 2, there is no high basic weight part 12 and the low basic weight part 13, and the basic weight of the whole elastic nonwoven fabric is uniform in the whole surface, 37.7 g / m < ² > on the whole, 16 in an elastic fiber layer .6g / m ^2, an inelastic fibrous layer is 21.1 g / m ^2. The rest is the same as in the second embodiment.

  From the evaluation results of the examples and comparative examples, for example, the following can be understood. In Example 1, as compared with Comparative Example 1, the width shrinkage is small when stretched in the MD direction, and as shown in FIG. 21, a stretchable nonwoven fabric having a high basis weight portion and a low basis weight portion having different stretch properties. there were. Moreover, in Example 2, as shown in FIG. 22, it was a stretchable nonwoven fabric having a high basis weight portion and a low basis weight portion having different stretch properties and having a good touch.

Fig.1 (a) is a schematic diagram which shows the cross-section of 1st Embodiment of the elastic nonwoven fabric of this invention, FIG.1 (b) is a top view which shows the elastic nonwoven fabric of 1st Embodiment. Fig.2 (a) is a typical side view which shows the 1st embodiment of the manufacturing method of the elastic nonwoven fabric of this invention, FIG.2 (b) is a perspective view which shows the spinning apparatus in a 1st embodiment. . FIG. 3 is a schematic side view showing a spinning device by a spunbond method. FIG. 4 is a schematic side view showing a spinning device by a spinning blow method. Fig.5 (a) is a schematic diagram which shows the cross-section of 2nd Embodiment of the elastic nonwoven fabric of this invention, FIG.5 (b) is a top view which shows the elastic nonwoven fabric of 2nd Embodiment. FIG. 6: is a typical perspective view which shows the front | former stage of the 2nd embodiment of the manufacturing method of the elastic nonwoven fabric of this invention. FIG. 7: is a typical perspective view which shows the back | latter stage of the 2nd embodiment of the manufacturing method of the elastic nonwoven fabric of this invention. FIG. 8 is a perspective view showing a state in which the stretchable nonwoven fabric is stretched in the MD direction. FIG. 9 is a cross-sectional view showing a state in which the stretchable nonwoven fabric is stretched in the MD direction. FIG. 10 is a schematic view showing a cross-sectional structure of a third embodiment of the stretchable nonwoven fabric of the present invention. FIG. 11 is a plan view showing another arrangement form of the high basis weight portion and the low basis weight portion. FIG. 12 is a perspective view showing an embodiment of a pants-type disposable diaper according to the present invention. FIG. 13 is a plan view showing a developed state of the disposable diaper shown in FIG. 14 is an exploded perspective view of the disposable diaper shown in FIG. 15 is a cross-sectional view taken along line XX in FIG. FIG. 16 is a plan view showing an absorbent core in the disposable diaper shown in FIG. 12. FIG. 17 is a perspective view showing a diaper in which the position of the peripheral edge of the abdominal waist opening is shifted from the position of the peripheral edge of the back waist opening. FIG. 18 is an explanatory diagram showing the iliac bone. FIG. 19 is an explanatory diagram illustrating a method of calculating the slip-off force at the wearer's waist. FIG. 20 is an explanatory diagram showing a method for measuring the height of the superior anterior iliac spine. FIG. 21 is a line graph showing the expansion / contraction characteristics of Example 1 and Comparative Example 1. FIG. 22 is a line graph showing the expansion / contraction characteristics of Example 1 and Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic fiber layer 1 'Elastic fiber web 1A Elastic fiber 2,3 Non-elastic fiber layer 2' Non-elastic fiber web 10 Stretch nonwoven fabric 10A Fiber sheet 10B (Lamination) Fiber sheet 12 High basic weight part 13 Low basic weight part

Claims (2)

Melt spun elastic fibers made of a thermoplastic elastomer using a spinning apparatus capable, a method for producing a stretched or squeezed nonwoven,
The stretchable nonwoven fabric includes at least an elastic fiber layer, and in an unstretched state, the elastic fiber layer is relatively relative to a high basis weight portion having a relatively high basis weight in the CD direction orthogonal to the machine direction at the time of manufacture. Low basis weight parts with low basis weight are arranged alternately,
Spinning apparatus is different to the land length before Symbol CD direction having a pore diameter or spinning nozzles of spinning nozzle, thereby spinning the mass of elastic fibers per unit width has provided a large portion and a small portion in the CD direction ,
Elasticity is produced by spinning elastic fibers with a spinning device, forming the elastic fibers thus spun on a conveyor to form a piled sheet , and producing the stretchable nonwoven fabric using the piled sheet as the elastic fiber layer . Nonwoven fabric manufacturing method. Melt spun elastic fibers made of a thermoplastic elastomer using a spinning apparatus capable, a method for producing a stretched or squeezed nonwoven,
The stretchable nonwoven fabric includes at least an elastic fiber layer, and in an unstretched state, the elastic fiber layer is relatively relative to a high basis weight portion having a relatively high basis weight in the CD direction orthogonal to the machine direction at the time of manufacture. Low basis weight parts with low basis weight are arranged alternately,
The elastic fiber is spun by a spinning device, and the spun elastic fiber is sucked by suction air having a high-speed part and a low-speed part in the CD direction so that the mass of the elastic fiber in the air conveying state is forming a large portion and a small part in the CD direction, to form the product fiber sheet with fiber stacking the elastic fibers, a laminate fiber sheets to produce the elastic nonwoven fabric to the elastic fiber layer,
The suction air having a high speed part and a low speed part in the CD direction is directed to the conveyor belt by a vacuum mechanism disposed on the back side of the conveyor belt having a net-like transport surface on which the elastic fibers are deposited. A method for producing a stretchable nonwoven fabric.

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