JP5230123B2 - Elastic nonwoven fabric - Google Patents

Description

  The present invention relates to a stretchable nonwoven fabric.

  There has been proposed an elastic stretch composite sheet obtained by laminating an elastic sheet made of an elastic stretch film or elastic stretchable continuous fibers and a fiber assembly having inelastic stretchability (see Patent Document 1). ). The elastic sheet and the fiber assembly are joined at joints arranged intermittently. The constituent fibers of the fiber assembly are long fibers that are continuous between the joints. The long fibers are not welded or fused between the joints, and the fibers are separated and independent from each other. Moreover, this long fiber has drawn the irregular curve between junction parts.

  According to Patent Document 1, in this elastic stretchable composite sheet, since the long fibers of the fiber assembly draw an irregular curve between the joint portions, when the sheet is stretched, the stretch is the fibers. It is said that it will not be disturbed by the aggregate. However, since the long fibers of the fiber assembly are separated and independent from each other between the joint portions, the elastic stretchable composite sheet has low strength against tension. Also, the peel strength between the fiber assembly and the elastic sheet is low. In addition, the long fibers tend to float between the joints, whereby the sheet has a fuzzy appearance and the appearance is not good.

  Apart from the elastic stretchable composite sheet described above, various stretchable nonwoven fabrics including elastic fibers made of an elastomer resin are known. For example, U.S. Patent No. 6,057,033 describes an elastomeric nonwoven fabric comprising microfibers comprising an extrudable elastomeric composition comprising at least about 10% by weight ABA block copolymer and polyolefin. However, since the microfiber contains polyolefin as a constituent resin, the microfiber does not have sufficient expansion and contraction characteristics.

  Patent Document 3 describes a composite elastic material having an anisotropic elastic fiber web having an elastomer meltblown fiber layer and an elastomer filament layer, and a gatherable layer bonded to the web. The material constituting the elastomer filament is 40 to 80% by weight of elastomer polymer and 5 to 40% by weight of resin adhesive. As described above, since the elastomer filament contains a resin other than the elastomer resin, the stretch characteristic is not sufficient due to the resin.

  Patent Document 4 discloses a stretchable composite sheet having an elastic sheet made of a fiber or film containing 60 to 98% by weight of a styrene elastomer having a styrene content of 10 to 40% by weight and a number average molecular weight of 70,000 to 150,000. Have been described. In addition to the styrene elastomer, the fiber or film contains materials other than the elastomer, such as an olefin resin and an oil component. Due to the inclusion of these materials, the stretchable composite sheet does not have sufficient stretch properties.

  Patent Document 5 is obtained by adding hydrogen to a double bond based on isoprene in a block copolymer composed of a polymer block A mainly composed of styrene and a polymer block B mainly composed of isoprene. A stretchable nonwoven fabric made of styrene elastomer fibers is described. However, this nonwoven fabric has a low modulus, and it cannot be said that the expansion and contraction hysteresis is sufficient.

JP 2001-79972 A JP 62-84143 A Japanese Patent Laid-Open No. 5-27043 JP 2002-361766 A JP 4-11059 A

  Accordingly, an object of the present invention is to provide a stretchable nonwoven fabric that can eliminate the drawbacks of the prior art described above.

  The present invention provides a stretchable nonwoven fabric including elastic fibers and non-elastic fibers whose thickness along the longitudinal direction is not uniform.

In the present invention, at least one surface of the web containing elastic fibers is arranged with a web containing low-stretch non-elastic fibers having an elongation of 80 to 800%,
For these webs, in a state where they are not integrated, an air-through hot air treatment is performed to thermally fuse the intersections of the fibers to obtain a fiber sheet in which these webs are integrated,
The present invention provides a method for producing a stretchable nonwoven fabric, in which the fiber sheet is stretched in at least one direction to stretch the low-stretched inelastic fiber, and then the stretching of the fiber sheet is released.

Furthermore, the present invention provides an air-through hot air treatment to a web containing elastic fibers and low-stretched inelastic fibers having an elongation of 80 to 800% to thermally bond the intersections of the fibers to obtain a fiber sheet. ,
The present invention provides a method for producing a stretchable nonwoven fabric, in which the fiber sheet is stretched in at least one direction to stretch the low-stretched inelastic fiber, and then the stretching of the fiber sheet is released.

  According to the stretchable nonwoven fabric of the present invention, high elongation and high strength are compatible. Therefore, the stretchable nonwoven fabric of the present invention is hardly broken even when it is stretched. In addition, the stretchable nonwoven fabric of the present invention has a good touch due to non-elastic fibers whose thickness is not uniform.

  The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 shows a schematic diagram of a cross-sectional structure in an embodiment of the stretchable nonwoven fabric of the present invention. The stretchable nonwoven fabric 10 of this embodiment is configured by laminating the same or different substantially inelastic non-elastic fiber layers 2 and 3 on both surfaces of the elastic fiber layer 1. Laminating non-elastic fiber layers on both surfaces of the elastic fiber layer 1 is preferable in terms of blocking prevention and handling as compared to the case of laminating only one surface.

  As the constituent fiber of the elastic fiber layer 1, for example, a fiber made from a thermoplastic elastomer, rubber or the like can be used. In particular, when the stretchable nonwoven fabric of the present embodiment is produced by the air-through method, it is preferable to use fibers made of thermoplastic elastomer as a raw material. The reason for this is that fibers made from thermoplastic elastomers can be melt-spun using an extruder in the same way as ordinary thermoplastic resins, and the fibers thus obtained are easy to heat-seal. It is. 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 particular, use of a styrene-based elastomer, an olefin-based elastomer, or a combination thereof is preferable in terms of moldability, elastic properties, and cost of elastic fibers.

  In particular, it is preferable to use a resin containing a thermoplastic elastomer made of a specific block copolymer as a constituent resin of the elastic fiber contained in the elastic fiber layer 1. The stretchable nonwoven fabric using this block copolymer has a high modulus and good stretch hysteresis compared to a conventional stretchable nonwoven fabric. Therefore, stretchable nonwoven fabrics using this block copolymer exhibit good stretchability even if the amount of elastic fibers used is reduced, so they are thin, have good breathability and touch, are easy to stretch, and have moderate shrinkage. Have power. This block copolymer is characterized by having the structure and dynamic viscoelastic properties described below.

  The block copolymer includes a polymer block A mainly composed of an aromatic vinyl compound. Examples of the aromatic vinyl compound include styrene, p-methylstyrene, m-methylstyrene, p-tert-butylstyrene, α-methylstyrene, chloromethylstyrene, p-tert-butoxystyrene, dimethylaminomethylstyrene, dimethylamino. Examples include ethyl styrene and vinyl toluene. Of these aromatic compounds, styrene is preferably used from an industrial viewpoint.

  The polymer block A is preferably contained in the block copolymer in an amount of 10 to 50% by weight, more preferably 15 to 30% by weight. By setting the amount of the polymer block in the block copolymer to 10 to 50% by weight, the moldability and heat resistance of the block copolymer will be satisfactory, and the stretchability and flexibility of the block copolymer are good. become.

  In addition to the polymer block A, the block copolymer includes a polymer block B mainly composed of a repeating unit represented by the following formula (1). The amount of polymer block B in the block copolymer is the remainder of the amount of polymer block A in the block copolymer. That is, the amount of the polymer block B in the block copolymer is preferably 50 to 90% by weight, more preferably 70 to 85% by weight.

  The polymer block B may further contain a repeating unit represented by the following formula (2) in addition to the repeating unit represented by the formula (1). The repeating unit represented by the formula (2) can be contained in the polymer block B in an amount of 20 mol% or less, particularly 10 mol% or less. Of course, the polymer block B may not include the repeating unit represented by the formula (2).

  There are various arrangement modes of the polymer block A and the polymer block B in the block copolymer. A linear arrangement pattern, particularly a triblock whose basic type is ABA type is preferable from the viewpoint of good stretch properties of the block copolymer.

  In addition to having the above-mentioned structure, the block copolymer preferably has the dynamic viscoelastic properties described below. As a result, the stretchable nonwoven fabric including elastic fibers made of this block copolymer has a higher modulus and good stretch hysteresis compared to conventional stretchable nonwoven fabrics. The high modulus means that the basis weight of the stretchable nonwoven fabric is lowered for the purpose of improving air permeability and touch, and the nonwoven fabric is made thin, or the fiber diameter of the elastic fiber is reduced. This is advantageous because good stretch properties are exhibited. That is, the stretchable nonwoven fabric becomes easy to stretch, and the strength when shrinking from the stretched state increases. Therefore, the stretchable nonwoven fabric containing elastic fibers made of this block copolymer is particularly suitable as a sheet constituting the entire exterior surface of a pants-type disposable diaper, for example.

  Moreover, the elastic fiber comprised from a block copolymer also has an advantage that it is less sticky or tacky than other general elastomer fibers. Also by this, the stretchable nonwoven fabric including the elastic fiber composed of the block copolymer has a good touch.

The block copolymer preferably has a storage elastic modulus G ′ of dynamic viscoelasticity measured at 20 ° C. and a frequency of 2 Hz, preferably 1 × 10 ⁴ to 8 × 10 ⁶ Pa, more preferably 5 × 10 ^{4 to} 5 × 10. ⁶ Pa, more preferably 1 × 10 ⁵ to 1 × 10 ⁶ Pa. In addition, the block copolymer preferably has a dynamic loss tangent tan δ value of dynamic viscoelasticity measured at 20 ° C. and a frequency of 2 Hz, preferably 0.2 or less, more preferably 0.1 or less, and still more preferably 0. .05 or less. There is no particular limitation on the lower limit of the tan δ value. The smaller the value, the better. However, the lower limit value that can be achieved by the current industrial technique is about 0.005.

  The storage elastic modulus G ′ is an index representing an elastic component in the dynamic viscoelasticity measurement of the block copolymer, that is, an index representing hardness. On the other hand, the dynamic loss tangent tan δ value is represented by the ratio G ″ / G ′ of the storage elastic modulus G ′ and the loss elastic modulus G ″, and is an index representing how much energy is absorbed when the block copolymer is deformed. It is. By setting the value of the storage elastic modulus G ′ of the block copolymer within the above range, the modulus can be set to an appropriate value, the hysteresis of expansion and contraction is improved, and a large force is not applied. The nonwoven fabric stretches. Thereby, the non-woven fabric feels good. Furthermore, residual strain can be reduced. On the other hand, by setting the dynamic loss tangent tan δ value of the block copolymer to be equal to or less than the above upper limit value, the residual strain when the nonwoven fabric is stretched can be reduced, and the stretch property can be made sufficient. it can.

  As described above, the dynamic viscoelasticity measurement of the block copolymer is performed in a tensile mode at 20 ° C., a frequency of 2 Hz. The applied strain is 0.1%. The specific measurement in this embodiment was performed using Physica MCR500 manufactured by Anton Paar. The sample was a plate having a length of 30 mm, a width of 10 mm, and a thickness of 0.8 mm.

  The block copolymer can be synthesized, for example, by the following process. First, an aromatic vinyl compound and a conjugated diene compound are added in an appropriate order to a hydrocarbon solvent such as cyclohexane, and an anionic polymerization is performed using an organolithium compound or metallic sodium as an initiator to have a double bond based on a conjugated diene. A copolymer is obtained. As the conjugated diene compound, for example, 1,3-butadiene, isoprene, pentadiene, hexadiene and the like are used. It is particularly preferable to use isoprene.

  Next, hydrogen is added to the double bond based on the conjugated diene of this copolymer, and the target block copolymer is obtained. The hydrogenation rate of the double bond based on the conjugated diene is preferably 80% or more, particularly 90% or more from the viewpoint of heat resistance and weather resistance. The hydrogenation reaction can be performed using a noble metal catalyst such as platinum or palladium, an organic nickel compound, an organic cobalt compound, or a composite catalyst of these compounds and another organic metal compound. The hydrogenation rate is calculated by an iodine value measurement method.

  A commercial item can also be used as a block copolymer. Examples of such commercial products include SEPTON (registered trademark) 2004 and SEPTON (registered trademark) 2002 which are styrene-ethylene-propylene-styrene block copolymers available from Kuraray Co., Ltd.

  When the block copolymer is used as the resin component of the elastic fiber contained in the elastic fiber layer 1, the elastic fiber may be composed only of the block copolymer or the block copolymer. And other resins may be included. When an elastic fiber contains the said block copolymer and other resin, it is preferable that content of the block copolymer in an elastic fiber is 20 to 80 weight%, especially 40 to 60 weight%.

  When the elastic fiber contains the block copolymer and other resin, examples of the other resin include polyethylene, polypropylene, polyolefin resin made of a copolymer of propylene and ethylene, polyester made of polyethylene terephthalate, etc. Resins that can be melt-spun, such as a series resin and a polyamide resin, can be used.

  When the elastic fiber contains the block copolymer, the fiber form of the elastic fiber includes (a) the block copolymer alone or a blend of the block copolymer and another resin. Examples thereof include fibers, and (b) core-sheath type or side-by-side type composite fibers containing the block copolymer and another resin as constituent resins. In particular, it is preferable to use a single fiber composed of the block copolymer alone.

  Whatever the resin component of the elastic fiber is used, the elastic fiber may be in the form of continuous fiber or short fiber. Preferably, it is in the form of continuous fibers. This is because if the elastic fiber is a continuous fiber, it is continuously stretched by hot air from the nozzle lip, so that there is an advantage that not only the fiber diameter is reduced but also the variation in the fiber diameter is reduced. Moreover, the same tendency is observed when stretching with cold air. As a result, the texture when viewed through the nonwoven fabric is improved, and the variation in the stretch properties of the nonwoven fabric is reduced. The fact that a thin fiber diameter can be obtained can reduce the capacity of hot air and cold air, which is advantageous in terms of manufacturing cost.

  The constituent fiber of the elastic fiber layer 1 has a fiber diameter of 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 air permeability and stretchability.

  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 of the nonwoven fabric. 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 including elastic fibers. 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 elastic fiber forming method includes, for example, a melt blown method in which a molten resin is extruded from a nozzle hole, and the extruded molten resin is elongated by hot air to thin the fiber, and a semi-molten resin is cooled by cold air. There is a spunbond method in which stretching is performed by a mechanical draw ratio. Moreover, an elastic fiber can also be manufactured by the spinning blow method which is a kind of melt spinning method.

  Moreover, the elastic fiber layer 1 may be in the form of a web or a nonwoven fabric containing elastic fibers. 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. Particularly preferred is a web obtained by the spinning blow method.

  In the spinning blown method, a pair of hot air discharge portions are disposed opposite to each other around the nozzle, and a pair of cold air discharge portions are disposed opposite to each other downstream from the nozzle. Use a spinning die. According to the spinning blow method, the stretch of the molten fiber by hot air and the cold stretch by cold air are continuously performed, so that there is an advantage that the stretchable 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 an advantage that a 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 is extremely advantageous in the present embodiment because it is less likely to break at the time of high elongation than the short fiber web and easily develops elasticity.

  Examples of the spinning die 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, The thing described in FIG. 2 of 174008 gazette can be used. Furthermore, what is shown in FIGS. 1 to 3 of Japanese Patent No. 3335949 can be used. The fibers spun from the spinning die are deposited on a collection net conveyor.

  The inelastic fiber layers 2 and 3 are extensible but substantially inelastic layers. The stretchability here refers to the case where the constituent fibers themselves are stretched, and even if the constituent fibers themselves are not stretched, the two fibers that have been heat-sealed at the intersection of the fibers are separated from each other, or the fibers are thermally fused. The three-dimensional structure formed by a plurality of fibers may be structurally changed due to wearing or the like, and the constituent fibers may be broken, and the whole fiber layer may be elongated.

  The inelastic fiber layers 2 and 3 contain substantially inelastic fibers. This fiber is characterized by the fact that the thickness of the fiber is not uniform in the length direction (hereinafter, this fiber is referred to as an indefinite fiber). That is, indefinite-diameter fibers have a large fiber cross-sectional area (diameter) and a small part when viewed along the length direction. In a non-constant diameter fiber, the thickness may change continuously from the thinnest part to the thickest part. Alternatively, the fiber thickness may be changed in a substantially step shape, as in the necking phenomenon observed in the undrawn yarn drawing process.

  The indefinite fiber is preferably made from a low-stretched inelastic fiber having a constant fiber diameter. When the stretchable nonwoven fabric of the present embodiment is manufactured using low-stretched fibers as a raw material according to the manufacturing method described later, the stretched low-stretched fibers in the manufacturing process result in thin portions of the fibers, resulting in the above-mentioned indefinite fiber Is formed. As a result, in the manufacturing process of the stretchable nonwoven fabric of the present embodiment, the joining point between the fibers and the joining point between the inelastic fiber layer and the elastic fiber layer are not easily destroyed, so the stretchable nonwoven fabric is maintained while maintaining the stretch performance. Thus, a stretchable nonwoven fabric having both high elongation and high strength can be obtained. Moreover, in the manufacturing process of the stretchable nonwoven fabric of the present embodiment, the joints between the indefinite fibers are not easily broken, so that the inelastic fiber layer is less likely to become fluffy. This is advantageous from the viewpoint of improving the appearance of the stretchable nonwoven fabric of the present embodiment. On the other hand, in the elastic stretchable composite sheet described in Patent Document 1 described in the background art section, the strength of the sheet is lowered because the fibers are not welded or mechanically entangled in the stretching process. Therefore, it is impossible to achieve both high elongation and high strength.

  Furthermore, by using the low-stretched fiber as a raw material, the number (length) of thin fibers is substantially increased as compared to before fiber stretching. Thereby, the concealability of the stretchable nonwoven fabric of this embodiment is improved. The improvement in the non-woven fabric concealment is that, for example, when the nonwoven fabric is used as a surface sheet of an absorbent article such as a sanitary napkin or a disposable diaper, the body fluid absorbed by the absorbent body becomes difficult to see through the surface sheet. Is advantageous.

  In addition, when the thickness of the indefinite fiber is periodically changed, the surface of the non-elastic fiber layer is finely wavy, and there is an additional effect that the touch is improved. In this case, the period of change, that is, the distance between the thickest part and the thickest part adjacent thereto is preferably 0.5 to 2.5 mm, particularly preferably 0.8 to 1.5 mm. This period can be measured from microscopic observation of the inelastic fiber layer.

  From the viewpoint of making the above effects even more remarkable, the indefinite fiber is preferably 2 to 15 μm in thickness at the thinnest part, more preferably 5 to 12 μm, and preferably 10 to 10 at the thickest part. 30 μm, more preferably 12 to 25 μm. The thickness of the indefinite fiber can be measured by microscopic observation of the inelastic fiber layer.

  It is preferable that the non-elastic fiber before stretching, which is a raw material for the indefinite fiber, has a fiber-to-fiber fusion point strength higher than the strength at 100% elongation of the non-elastic fiber. This is preferable from the viewpoint that when the stretchable nonwoven fabric is stretched, the fusion point between the fibers is not easily broken, and the strength of the nonwoven fabric is difficult to decrease. The fusion point strength is measured according to the description in paragraph [0040] of Japanese Patent Application Laid-Open No. 2004-218183 relating to the previous application of the present applicant. The strength at 100% elongation is measured using a tensile tester under conditions of a distance between chucks of 20 mm and a tensile speed of 20 mm / min.

  As described above, the non-constant fiber is preferably made from a low-stretched inelastic fiber having a constant fiber diameter. In this case, the low-stretched fiber may be a fiber made of a single raw material, or a composite fiber using two or more raw materials, such as a core-sheath type composite fiber or a side-by-side type composite fiber. Good. Considering the ease of joining the indefinite fiber and the ease of joining the non-elastic fiber layer and the elastic fiber layer, it is preferable to use a composite fiber. In the case of the core-sheath type composite fiber, the core is preferably polyester (PET or PBT) or polypropylene (PP), and the sheath is preferably low melting point polyester (PET or PBT), polypropylene (PP) or polyethylene (PE). In particular, the use of these composite fibers is preferable in that the heat fusion with the constituent fibers of the elastic fiber layer containing the polyolefin-based elastomer becomes strong and layer peeling hardly occurs.

  The indefinite fiber may be a short fiber such as a staple fiber or a long fiber such as a continuous filament. In view of the method for producing a stretchable nonwoven fabric described later, it is preferable to use short fibers. The indefinite fiber may be hydrophilic or water repellent.

  The non-elastic fiber layers 2 and 3 may be composed of only indefinite-diameter fibers, or may include other non-elastic fibers having a constant diameter in addition to the indefinite-diameter fibers. Examples of other inelastic fibers include fibers made of PE, PP, PET, PBT, polyamide, and the like. Other inelastic fibers 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. When the non-elastic fiber layers 2 and 3 include non-constant diameter non-elastic fibers in addition to the indefinite fiber, the amount of the other non-elastic fibers is 1 to 30% by weight, particularly 5 to 20% by weight. % Is preferred.

  The inelastic fiber layers 2, 3 can be continuous filaments or short fiber webs or nonwovens. In particular, a short fiber web is preferable from the viewpoint of forming thick and bulky inelastic fiber layers 2 and 3. The two inelastic fiber layers 2 and 3 may be the same or different with respect to the material, basis weight, thickness, and the like of the constituent fibers. Moreover, indefinite diameter fiber may be contained only in one inelastic fiber layer among the two inelastic fiber layers 2 and 3.

  At least one of the two non-elastic fiber layers 2 and 3 is preferably 1.2 to 20 times, particularly 1.5 to 5 times as thick as the elastic fiber layer 1. On the other hand, regarding the basis weight, it is preferable that the basis weight of the elastic fiber layer is higher than the basis weight of at least one of the two inelastic fiber layers 2 and 3. In other words, the non-elastic fiber layer is preferably thicker and has a smaller basis weight than the elastic fiber layer. By having such a relationship between the thickness and the basis weight, the inelastic fiber layer becomes thicker and bulkier than the elastic fiber layer. As a result, the stretchable nonwoven fabric 10 is soft and has a good texture.

Regarding the thickness of the non-elastic fiber layers 2 and 3, it 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 layers 2 and 3, specifically 0.01 to 2 mm, particularly 0.1 to 0.5 mm. preferable. The thickness is obtained by the following method after leaving the stretchable nonwoven fabric in an environment of 20 ± 2 ° C. and 65 ± 2% RH under no load for 2 days or more. First, an elastic nonwoven fabric is sandwiched between flat plates with a load of 0.5 cN / cm ² . Under this condition, the microscope is observed at a magnification of 50 to 200 times with a microscope, the average thickness is obtained in each field of view, and the average value of the thicknesses of three fields of view can be obtained.

For the basis weight itself of the non-elastic fibrous layers 2 and 3, from the viewpoints of and residual strain which covers the surface of the elastic fiber layer uniform, respectively 1~60g / m ^2, to be particularly 5 to 15 g / m ² preferable. On the other hand, the basis weight itself of the elastic fiber layer 1 is preferably larger than the basis weight of the non-elastic fiber layers 2 and 3 from the viewpoint of stretch characteristics and residual strain. Specifically, it is preferably 5 to 80 g / m ² , particularly 10 to 40 g / m ² .

  As shown in FIG. 1, in this embodiment, the elastic fiber layer 1 and the non-elastic fiber layers 2 and 3 are formed by heat fusion at the fiber intersection in a state in which the constituent fibers of the elastic fiber layer 1 maintain the fiber form. It is joined all over by wearing. That is, the joining state differs from the conventional stretchable nonwoven fabric that is partially joined. In the stretchable nonwoven fabric 10 of the present embodiment in which the elastic fiber layer 1 and the non-elastic fiber layers 2 and 3 are joined together, the interface between the elastic fiber layer 1 and the non-elastic fiber layers 2 and 3 and the vicinity thereof. In FIG. 2, the intersections of the constituent fibers of the elastic fiber layer 1 and the constituent fibers of the non-elastic fiber layers 2 and 3 are heat-sealed, and are bonded substantially uniformly over the entire surface. By being bonded over the entire surface, it is possible to prevent the floating between the elastic fiber layer 1 and the non-elastic fiber layers 2 and 3, that is, the formation of a space by separating both layers. When floating occurs between the two layers, there is no sense of unity between the elastic fiber layer and the non-elastic fiber layer, and the texture of the stretchable nonwoven fabric 10 tends to decrease. According to the present invention, 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, or the like, a film or film- A state in which the fiber structure is not deformed. There exists an advantage that sufficient breathability is provided to the elastic nonwoven fabric 10 of this embodiment because the constituent fiber of the elastic fiber layer 1 is in the state of maintaining the fiber form.

  In the elastic fiber layer 1, the intersections of the constituent fibers are thermally fused in the layer. Similarly, in the inelastic fiber layers 2 and 3, the intersections of the constituent fibers are heat-sealed in the layers.

  In at least one of the two non-elastic fiber layers 2 and 3, a part of the constituent fibers are in the elastic fiber layer 1, and / or a part of the constituent fibers of the elastic fiber layer is at least one of the two. The inelastic fiber layers 2 and 3 are in a state of entering. By being in such a state, integration of the elastic fiber layer 1 and the non-elastic fiber layers 2 and 3 is promoted, and it is more effectively prevented that floating occurs between both layers. As a result, the layers are combined with each other following the surface of each layer. Part of the constituent fibers of the non-elastic fiber layer enters the elastic fiber layer 1 and remains there, or penetrates through the elastic fiber layer 1 and reaches the other non-elastic fiber layer. When the surface connecting the surface fibers in each layer is assumed macroscopically, a part of the constituent fibers of the other layer enters the cross-sectional thickness direction of the layer from this surface into the fiber space formed inside the layer. It is out. When the constituent fibers of the non-elastic fiber layer enter the elastic fiber layer 1 and remain there, it is preferable that the constituent fibers are further entangled with the constituent fibers of the elastic fiber layer 1. Similarly, when the constituent fiber of the non-elastic fiber layer penetrates through the elastic fiber layer 1 and reaches the other non-elastic fiber layer, the constituent fiber is the same as the constituent fiber of the other non-elastic fiber layer. Preferably they are entangled. This is confirmed by the fact that no space is substantially formed between the layers when the cross section in the thickness direction of the stretchable nonwoven fabric is observed with an SEM or a microscope. The term “entanglement” as used herein means a state in which 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, for example, after applying the air-through method without overlapping the fiber layer and heat fusion, the force required to peel the fiber layer from the state where the fiber layer is simply overlapped In comparison with the force to peel off the fiber layer, if there is a substantial difference between them, it can be determined that they are entangled.

  In order to allow the constituent fibers of the non-elastic fiber layer to enter the elastic fiber layer and / or to allow the constituent fibers of the elastic fiber layer to enter the non-elastic fiber layer, the constituent fibers of the non-elastic fiber layer and the non-elastic fiber layer 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 heat-sealed) before the process of thermally fusing the constituent fibers. 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.

  Further, it is preferable to use the air-through method in order to allow the constituent fibers of the non-elastic fiber layer to enter the elastic fiber layer 1 and / or to allow the constituent fibers of the elastic fiber layer to enter the non-elastic fiber layer. 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. In addition, by using the air-through method, it becomes easy to allow the constituent fibers of the inelastic fiber layer to enter the elastic fiber layer 1 while maintaining the bulkiness of the inelastic fiber layer. In the case where the constituent fibers of the non-elastic fiber layer are allowed to penetrate the elastic fiber layer 1 and reach the other non-elastic fiber layer, it is preferable to use the air-through method in the same manner. In particular, it is preferable to laminate an inelastic fiber layer in a web state with the elastic fiber layer and use the air-through method. In this case, the constituent fibers of the elastic fiber layer may be heat-sealed. Furthermore, as will be described later in the manufacturing method, by performing the air-through method under specific conditions, and for improving the flow of hot air, the breathability of the stretchable nonwoven fabric, particularly the breathability of the elastic fiber layer is high. By doing, a fiber 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. It is also possible to use a spunlace method, a needle punch method, etc., but in that case, the bulkiness of the inelastic fiber layer is impaired, or the constituent fibers of the elastic fiber layer appear on the surface. The texture of the resulting stretchable nonwoven fabric tends to decrease.

  In particular, when the constituent fibers of the non-elastic fiber layer are entangled with the constituent fibers of the elastic fiber layer 1, it is preferable that the non-elastic fiber layer is entangled only by the air-through method.

  In order to entangle the fibers by the air-through method, the gas blowing pressure, the blowing speed, the basis weight and thickness of the fiber layer, the conveying 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 inelastic fiber layer and the constituent fibers of the elastic fiber layer 1 cannot be entangled. As will be described later in the production method, the stretchable nonwoven fabric intended in the present invention is obtained 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 this 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, in the air-through method, the constituent fibers of the non-elastic fiber layer are allowed to enter the elastic fiber layer 1 or the constituent fibers are entangled with the constituent fibers of the elastic fiber layer 1 and the non-elastic fiber layer This operation is necessary for heat-sealing the constituent fibers of the elastic fiber layer and the constituent fibers of the elastic fiber layer. The direction in which the fibers enter varies depending on the passing direction of the heated gas and the positional relationship between the inelastic fiber layer and the elastic fiber layer. The inelastic fiber layer is preferably an air-through nonwoven fabric in which fiber intersections are fused in the constituent fibers by an air-through method.

  As is apparent from the above description, in the preferred form of the stretchable nonwoven fabric of the present embodiment, the elastic fiber in a state in which the constituent fibers maintain the fiber form inside the thickness direction of the substantially inelastic inelastic air-through nonwoven fabric. Layer 1 is included, and a part of the constituent fibers of the air-through nonwoven fabric enters the elastic fiber layer 1 and / or a part of the constituent fibers of the elastic fiber layer enters the inelastic fiber layer. It has become. 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. Since the elastic fiber layer 1 is included in the air-through nonwoven fabric, the constituent fibers of the elastic fiber layer 1 are not substantially present on the surface of the stretchable nonwoven fabric. This is preferable from the point that the stickiness peculiar to an elastic fiber does not arise.

  In the stretchable nonwoven fabric 10 of this embodiment, as shown in FIG. 1, minute recesses are formed in the inelastic fiber layers 2 and 3. Thereby, the cross section of the stretchable nonwoven fabric 10 has a waveform shape microscopically. This waveform shape is generated by stretching 10 stretchable nonwoven fabrics, as will be described later in the manufacturing method. This corrugated shape is generated as a result of imparting stretchability to the stretchable nonwoven fabric 10 and does not significantly affect the texture of the nonwoven fabric 10 itself. Rather, it is advantageous in that a softer and better nonwoven fabric can be obtained.

  Although not shown in FIG. 1, the stretchable nonwoven fabric 10 of the present embodiment may be embossed. Embossing is performed for the purpose of further increasing the bonding strength between the elastic fiber layer 1 and the non-elastic fiber layers 2 and 3. Therefore, if the elastic fiber layer 1 and the non-elastic fiber layers 2 and 3 can be sufficiently joined by the air-through method, it is not necessary to perform embossing. In the embossing, the constituent fibers are joined to each other. However, unlike the air-through method, the constituent fibers are not entangled depending on the embossing.

  The stretchable nonwoven fabric 10 of this embodiment has stretchability in at least one direction in the in-plane direction. It may have elasticity in all directions in the plane. In that case, it is not hindered that the degree of elasticity varies depending on the direction. Regarding 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 the time of 100% elongation, from the viewpoint of both easiness of extension and strength. A particularly important property regarding the stretchability of the stretchable nonwoven fabric 10 of the present embodiment is residual strain. As will be apparent from the examples described later, according to the stretchable nonwoven fabric 10 of the present embodiment, the value of the residual strain can be reduced. Specifically, the residual strain when contracted from the 100% stretched state is preferably a small value of 15% or less, more preferably 10% or less.

The stretchable nonwoven fabric 10 of this embodiment can be used for various uses such as surgical clothes and cleaning sheets from the viewpoint of its good texture, fuzz prevention, stretchability, and breathability. 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. Moreover, it can be used as a sheet or the like for forming a stretchable wing of a napkin. Moreover, even if it is another site | part, it can be used for the site | part etc. which want to provide a stretching property. The basis weight and thickness of the stretchable nonwoven fabric 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. In addition, the stretchable nonwoven fabric of the present invention is flexible and has high air permeability because the constituent fibers of the elastic fiber layer maintain the fiber form. Regarding the bending stiffness which is a measure of flexibility, the stretchable nonwoven fabric of the present invention preferably has a bending stiffness value as low as 10 cN / 30 mm or less. Regarding the air permeability, the air permeability is preferably 16 m / (kPa · s) or more. The maximum strength in the stretching direction is preferably 200 cN / 25 mm or more. The maximum elongation in the expansion / contraction direction is desirably 100% or more.

  The bending stiffness is measured in accordance with JIS L-1096, and is obtained as an average value when bent in the flow direction and in a direction perpendicular to the flow direction, respectively, under the conditions of an indentation amount of 8 mm by a handle ohmmeter and a slit width of 10 mm. The air permeability is obtained as the reciprocal of the air resistance measured by AUTOMATIC AIR-PERMEABILITY TESTER KES-F8-AP1 manufactured by Kato Tech.

  Next, the preferable manufacturing method of the elastic nonwoven fabric 10 of this embodiment is demonstrated, referring FIG. FIG. 2 schematically shows a preferable manufacturing apparatus used in the method for manufacturing the stretchable nonwoven fabric 10 of the present embodiment. The apparatus shown in FIG. 2 includes a web forming unit 100, a hot air processing unit 200, and a stretching unit 300 in this order from the upstream side to the downstream side of the manufacturing process.

  The web forming unit 100 includes a first web forming device 21, a second web forming device 22, and a third web forming device 23. As the first web forming apparatus 21 and the third web forming apparatus 23, card machines are used. As the card machine, the same card machines as those normally used in the technical field can be used without particular limitation. On the other hand, as the second web forming device 22, a spinning blow spinning device is used. In the spinning blown spinning apparatus, a pair of hot air discharge portions are arranged opposite to each other around the nozzle near the tip of the molten polymer discharge nozzle, and a pair of cold air discharge portions downstream of the nozzle are centered on the nozzle. Opposing spinning dies are provided. The fibers spun from the spinning die are deposited on a collection net conveyor.

  The hot air processing unit 200 includes a hot air furnace 24. In the hot stove 24, heated gas heated to a predetermined temperature, particularly heated air is blown out. When three layers of webs stacked on top of each other are introduced into the hot stove, the heated gas is forced to penetrate from the top to the bottom of the web, in the opposite direction, or in both directions.

  The stretching unit 300 includes a weak joining device 25 and a stretching device 30. The weak joining device 25 includes a pair of embossing rolls 26 and 27. The weak joining device 25 is for ensuring the joining of the webs of the respective layers in the fiber sheet formed by the hot air processing unit 200. A stretching device 30 is disposed downstream of the weak joining device 25 and adjacent thereto. The stretching device 30 includes 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 direction and can be engaged with each other. . When the fiber sheet is caught between both the uneven rolls 33 and 34, the fiber sheet is stretched in the axial direction of the roll (that is, the width direction of the sheet).

  When the manufacturing method of the elastic nonwoven fabric using the apparatus which has the above structure is demonstrated, first, a pair of web which consists of the same or different inelastic fiber will be distribute | arranged to each surface of the web which consists of elastic fiber. The “web made of elastic fibers” means not only a web made only of elastic fibers but also an elastic fiber layer (a layer indicated by reference numeral 1 in FIG. 1) formed from the web, as long as it does not impair the elastic elasticity. Webs containing a small amount of inelastic fibers in addition to the fibers are also included.

  As shown in FIG. 2, in the web forming unit 100, inelastic fiber webs 3 ′ are manufactured by a card machine that is the first web forming device 21 using inelastic short fibers as a raw material. In the inelastic fiber web 3 ′, the constituent fibers may be temporarily joined as necessary. Examples of the temporary bonding means include air-through hot air blowing and heat fusion using a heat roll. A low-stretched inelastic fiber is used as the raw fiber of the inelastic fiber web 3 '. The term “low-drawn fiber” as used herein includes both a fiber drawn at a low draw ratio after spinning and an undrawn fiber, ie, an undrawn fiber. It is preferable to use a low-stretched fiber having an elongation of 80 to 800%, particularly 120 to 650%. By using a low-stretched fiber having an elongation in this range, the fiber is successfully stretched by the stretching device 30, and the above-described indefinite-diameter fiber is easily formed. The fiber diameter of the low-stretched fiber is preferably 10 to 35 μm, particularly preferably 12 to 30 μm.

  The elongation of the low-stretched fiber conforms to JIS L-1015, and is measured under the conditions of measuring environment temperature and humidity 20 ± 2 ° C., 65 ± 2% RH, tensile tester gripping distance 20 mm, and tensile speed 20 mm / min. Standard. In addition, when collecting fibers from an already manufactured non-woven fabric and measuring the elongation, when the gripping interval cannot be 20 mm, that is, when the length of the fiber to be measured is less than 20 mm, the gripping interval is set. Measure by setting to 10 mm or 5 mm.

  On the non-elastic fiber web 3 ′ that is continuously conveyed in one direction, an elastic fiber web 1 ′ composed of continuous filaments of elastic fibers manufactured by a spinning blown spinning device as the second web forming device 22 is collected on the collection net. Once deposited on the conveyor, they are stacked.

  On the elastic fiber web 1 ′, a non-elastic fiber web 2 ′ manufactured by a card machine which is the third web forming device 23 is laminated. The details of the non-elastic fiber web 2 ′ are the same as those of the above-described non-elastic fiber web 3 ′, and the description regarding the non-elastic fiber web 3 ′ is appropriately applied. The non-elastic fiber web 2 'may be the same as or different from the non-elastic fiber web 3' in terms of constituent fibers, basis weight, thickness, and the like.

  When the spinning blown method is used to form the elastic fiber web 1 ′, there is an advantage that the stretchable fiber can be easily formed because the melted fiber is continuously stretched by hot air and cold stretched by cold air. Further, since the fibers do not become too dense and elastic fibers having a thickness similar to short fibers can be formed, there is an advantage that a 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 is extremely advantageous in the present embodiment because it is less likely to break at the time of high elongation than the short fiber web and easily develops elasticity.

  The laminate of the three webs is sent to an air-through hot air furnace 24 where hot air treatment is performed. By the hot air treatment, the intersections of the fibers are thermally fused, and the elastic fiber web 1 'is joined to the non-elastic fiber webs 2' and 3 'on the entire surface. In the hot air treatment, it is preferable that the webs of the respective layers are not integrated. As a result, the bulky and thick state of each web is maintained even after the hot air treatment, and an elastic nonwoven fabric having a good texture can be obtained.

  In addition to heat-sealing the intersections of the fibers and bonding the webs of each layer to the entire surface by hot air treatment, some of the constituent fibers of the non-elastic fiber web 2 ′ located mainly on the hot air blowing surface side are elastic It is preferable to let it enter into the fiber web 1 '. Further, it is preferable that a part of the constituent fibers of the non-elastic fiber web 2 ′ is caused to enter the elastic fiber web 1 ′ and further entangled with the constituent fibers of the web 1 ′ by controlling the conditions of the hot air treatment. . Alternatively, it is preferable that a part of the constituent fibers of the non-elastic fiber web 2 ′ penetrate the elastic fiber web 1 ′ to reach the non-elastic fiber web 3 ′ and entangle with the constituent fibers of the web 3 ′. .

A part of the constituent fibers of the non-elastic fiber web 2 'is allowed to enter the elastic fiber web 1' and / or a part of the constituent fibers of the elastic fiber web 1 'is allowed to enter the non-elastic fiber web 2'. The conditions are preferably a hot air flow rate of 0.4 to 3 m / sec, a heat treatment time of 0.5 to 10 sec, a temperature of 80 to 160 ° C., and a conveying speed of 5 to 200 m / min. Particularly preferred is a hot air flow rate of 1 to 2 m / sec. If a high air permeability net is used for the air-through heat treatment, the fibers are more likely to enter through the air. Similarly, when the elastic fiber web 1 ′ is directly spun on the non-elastic fiber web 3 ′, the constituent fibers of the elastic fiber web 1 ′ easily enter the non-elastic fiber web 3 ′ due to wind during spinning. The net used for the hot air treatment and the net used for the direct spinning of the elastic fiber have an air permeability of 250 to 800 cm ³ / (cm ² · s), particularly 400 to 750 cm ³ / (cm ² · s). preferable. The above conditions are also preferred in terms of softening the fibers and allowing them to penetrate uniformly and fusing the fibers. Furthermore, in order to entangle the fiber, it becomes possible by setting the hot air flow rate to 3 to 5 m / second and the blowing 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, more preferably 24 m / (kPa · s) or more, the hot air can flow and the fibers can be more uniformly entrained. Therefore, it is preferable. Further, the fiber is well fused and the maximum strength is increased. In addition, 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 / or the configuration of the non-elastic fiber web 3 ′. It is preferable that the fibers and the constituent fibers of the elastic fiber web 1 ′ are heat-sealed at the intersections thereof. In this case, the hot air treatment is preferably performed under conditions such that the elastic fiber after the hot air treatment maintains the fiber form. That is, it is preferable to prevent the constituent fibers of the elastic fiber web 1 'from forming a film or film-fiber structure by hot air treatment. In the hot air treatment, the constituent fibers of the inelastic fiber web 2 ′ are heat-sealed at the intersection, and similarly, the constituent fibers of the elastic fiber web 1 ′ and the constituent fibers of the inelastic fiber web 3 ′ are intersected. Heat fusion.

  The fiber sheet 10B in which the three webs are integrated is obtained by the air-through hot air treatment. The fiber sheet 10B has a long band shape having a certain width and extending in one direction. The fiber sheet 10B is then conveyed to the stretching unit 300. In the stretching unit 300, the fiber sheet 10 </ b> B is first transported to the weak joining device 25. The weak joining device 25 is composed of an embossing device provided with a metal embossing roll 26 in which embossing convex portions are regularly arranged on the peripheral surface and a metal or resin receiving roll 27 arranged opposite thereto. The fiber sheet 10B is subjected to hot embossing by the weak joining device 25. As a result, a fiber sheet 10A that has been embossed is obtained. In addition, since the webs of the respective layers are joined and integrated by heat fusion performed by the hot air processing unit 200 prior to the hot embossing by the weak joining device 25, the hot embossing by the weak joining device 25 is performed according to the present invention. Is not essential. When it is desired to ensure the joining and integration of the webs of the respective layers, the heat embossing by the weak joining device 25 is effective. Moreover, according to the weak joining apparatus 25, in addition to the web integration of each layer, there exists an advantage that the fluff of the fiber sheet 10A can be suppressed.

  Since the hot embossing by the weak joining apparatus 25 is performed in an auxiliary manner to the heat fusion performed by the hot air processing unit 200, the processing conditions may be relatively mild. Conversely, if the conditions for hot embossing are severe, the bulkiness of the fiber sheet 10A is impaired, and a fiber film is formed, which negatively affects the texture and breathability of the finally obtained stretchable nonwoven fabric. From such a viewpoint, the linear pressure of hot embossing and the heating temperature of the embossing roll are set.

  As shown in FIG. 3, the fiber sheet 10 </ b> A obtained by the hot embossing has a large number of individual scattered joints 4. The joint 4 is formed in a regular arrangement pattern. It is preferable that the joining part 4 is formed discontinuously, for example, in both the flow direction (MD) and the orthogonal direction (CD) of the fiber sheet 10A.

  The fiber sheet 10 </ b> A that has been subjected to the heat embossing in the weak bonding apparatus 25 is continuously sent to the stretching apparatus 30. As shown in FIGS. 2 to 4, the fiber sheet 10 </ b> A is drawn with 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 apparatus 30 is stretched in a direction (CD) orthogonal to the transport direction (MD).

  The stretching device 30 is configured such that the shaft portion of one or both of the concavo-convex rolls 33 and 34 is displaced up and down by a known lifting mechanism so that the distance between them can be adjusted. As shown in FIG. 1 and FIGS. 4B and 4D, each concave-convex roll 33, 34 has a large-diameter portion 31 of one concave-convex roll 33 and a large-diameter portion 32 of the other concave-convex roll 34. The large-diameter portion 32 of the other concave-convex roll 34 is assembled so as to be loosely inserted between the large-diameter portions 31 of the one concave-convex roll 33. The fiber sheet 10A is bitten between the rolls 33 and 34 in this state, and the fiber sheet 10A is stretched.

In this stretching step, as shown in FIGS. 3 and 4, the position of the joint portion 4 in the width direction of the fiber sheet 10 </ b> A and the positions of the large diameter portions 31 and 32 of the uneven rolls 33 and 34 are matched. Is preferred. Specifically, as shown in FIG. 3, the fiber sheet 10 </ b> A is formed with a plurality of rows of joint portions in which a plurality of joint portions 4 are formed in a straight line along the MD (see FIG. 3). 3 in the 10 columns shown) in FIG. 3, most junction sequence R ₁ on the left side as the start, for the joint 4 included in each of the joint row R ₁ of every other therefrom, one uneven position of the large diameter portion 31 of the roll 33 do not match, including the junction sequence R ₂ of the second from the left, for the joint portions included in each of the joint row R ₂ of every other therefrom, the other The position of the large diameter portion 32 of the uneven roll 34 is made to coincide. In FIG. 3, the ranges indicated by reference numerals 31 and 32 indicate that the fiber sheet 10 </ b> A has a circumferential surface of the large-diameter portions 31 and 32 of each roll at one point in a state where the fiber sheet 10 </ b> A is engaged between both the uneven rolls 33 and 34. The overlapping range is shown.

  When the fiber sheet 10A passes between the rolls 33 and 34 in a state of being bitten between the concavo-convex rolls 33 and 34, as shown in FIGS. 4 (b) and (d), While the large-diameter portions 31 and 32 of any of the concave and convex rolls overlap, the region between the large-diameter portions that do not overlap with the large-diameter portions 31 and 32, that is, the region between the above-described joint row is positive in the width direction. Stretched. In particular, the low-stretched fibers contained in the non-elastic fiber layers 2 and 3 are stretched between the joints 4 to become thin, thereby forming an indefinite fiber. That is, the stretching force by the uneven rolls 33 and 34 mainly acts on the stretching of the low-stretched fiber, and an excessive force is not applied to the joint portion 4. As a result, it is possible to efficiently stretch the portion other than the joint portion of the fiber sheet 10A while preventing the joint portion 4 from being broken and peeling between the webs of each layer. Further, by this stretching, as shown in FIG. 5, the non-elastic fiber layers 2 and 3 are sufficiently stretched without breaking the bonding between the fibers, whereby the non-elastic fiber layers 2 and 3 become the elastic fiber layer 1. The degree of hindering the free expansion and contraction of the film greatly decreases. As a result, according to this production method, it is possible to efficiently produce a stretchable nonwoven fabric having high strength and high stretchability and having a good appearance with little tearing and fuzzing. In FIG. 5, the thickness of the non-elastic fiber is expressed uniformly for convenience.

  As described above, according to the present production method, the non-elastic fibers are successfully stretched, and the joint between the fibers is not broken by stretching, so that a decrease in sheet strength due to stretching is suppressed as much as possible. Specifically, the tensile strength of the fiber sheet A before stretching, that is, the tensile strength of the fiber sheet A after stretching relative to the tensile strength of the original stretch nonwoven fabric, that is, the tensile strength of the target stretch nonwoven fabric. The ratio is a value close to 1, such as 0.3 to 0.99, particularly 0.5 to 0.99, and further 0.7 to 0.99. The tensile strength here is measured in accordance with the maximum strength measuring method described in Examples described later.

  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 layers 2 and 3 are plastically deformed and stretched to make the fibers thinner. At the same time, the non-elastic fiber layers 2 and 3 become more bulky and feel better and cushioning becomes better.

  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 it 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 fibers used for the inelastic fiber layers 2 and 3, the embossing pattern of the embossing rolls, the pitches of the concavo-convex rolls 33 and 34, the thicknesses of the tips, and the meshing. Can be controlled by quantity.

The thickness was determined by the following method after the stretchable nonwoven fabric was left unloaded for 2 days or more in an environment of 20 ± 2 ° C. and 65 ± 2% RH. The stretchable nonwoven fabric was sandwiched between flat plates with a load of 0.5 cN / cm ^{2, and} the cross section was observed with a microscope at a magnification of 25 to 200 times under that condition, and the average thickness of each layer was determined. The total thickness was determined from the distance between the flat plates. Regarding the fiber penetration, the midpoint of mutual penetration was defined as the thickness.

  It is preferable that the peripheral surfaces of the large-diameter portions 31 and 32 of the uneven rolls 33 and 34 are not sharp so as not to damage the fiber sheet 10A. For example, as shown in FIGS. 4B and 4D, a flat surface having a predetermined width is preferable. The width W (see FIG. 4B) of the tip surfaces of the large-diameter portions 31 and 32 is preferably 0.3 to 1 mm, and is 0.7 to 2 times the dimension of the joint portion 4 in the CD direction. It is preferably 0.9 to 1.3 times. Thereby, the fiber form of inelastic fiber becomes difficult to be destroyed, and a high-strength stretchable nonwoven fabric is obtained.

The pitch P between the large diameter portions (see FIG. 4B) is preferably 0.7 to 2.5 mm. The pitch P is preferably 1.2 to 5 times, particularly 2 to 3 times, the dimension of the joint portion 4 in the CD direction. As a result, a stretchable nonwoven fabric having a cloth-like appearance and a good touch can be obtained. The pitch of the CD direction of the joint 4 (distance between joint row R ₁ adjacent), compared pitch P between the large-diameter portion, but is twice basically to match the positional relationship, the fibers Since the sheet 10A is stretched in the CD direction and necked in, the position can be matched within the range of 1.6 times to 2.4 times.

  As described above, the low-stretched fibers contained in the non-elastic fiber layers 2 and 3 are stretched and thinned to form an indefinite diameter fiber by meshing with the concavo-convex rolls 33 and 34. This meshing is utilized. By doing so, the thickness of the indefinite fiber is periodically changed. Specifically, the low-stretched fiber is stretched between adjacent large-diameter portions. The stretching of the low-stretched fiber changes according to the pitch P between the large diameter portions. Therefore, by adjusting the pitch P, the period of change in the thickness of the indefinite fiber can be controlled.

  The fiber sheet 10A sent out from the stretching device 30 is released from the stretched state in the width direction. That is, the elongation is eased. As a result, the fiber sheet 10A exhibits elasticity and the sheet 10A contracts in the width direction. This shrinkage causes sagging of the inelastic fibers between the joints between the fibers as shown in FIG. In this way, the desired stretchable 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 the stretched state is maintained to some extent as long as stretchability is exhibited. Good.

  Next, another embodiment of the present invention will be described. Regarding the points that are not particularly described with respect to the present embodiment, the description of the above-described embodiment is applied as appropriate.

  In the embodiment described above, the non-elastic fiber is included in the non-elastic fiber layer. However, in this embodiment, the non-elastic fiber is included in the elastic fiber layer. The stretchable nonwoven fabric of the present embodiment may have a single-layer structure composed of an elastic fiber layer including, for example, an elastic fiber and an inelastic indefinite fiber, or includes an elastic fiber and an inelastic indefinite fiber. A multilayer structure in which an inelastic fiber layer is disposed on at least one surface of the elastic fiber layer may be used.

  When the stretchable nonwoven fabric of the present embodiment has a single-layer structure, the nonwoven fabric includes elastic fibers and inelastic indefinite diameter fibers, and may further include inelastic fibers having a constant diameter. On the other hand, when the stretchable nonwoven fabric of the present embodiment has a multilayer structure, the inelastic fiber layer may or may not contain an indefinite fiber.

  Regardless of whether the stretchable nonwoven fabric of the present embodiment has a single-layer structure or a multilayer structure, in the elastic fiber layer, the weight ratio of the elastic fiber to the non-elastic fiber (the former / the latter) is 20/80 to 80/20, particularly 30/70 to 70/30 is preferable from the viewpoints of exhibiting good stretch properties and high strength, good touch, and improved texture. The term “non-elastic fiber” as used herein includes both non-elastic indefinite fiber and fixed-diameter non-elastic fiber.

  The elastic nonwoven fabric of this embodiment can be manufactured according to the manufacturing method of the elastic nonwoven fabric of embodiment mentioned above. Specifically, first, a web including elastic fibers and low-stretched inelastic fibers having an elongation of 80 to 800% is formed. For forming the web, for example, the spinning blow method can be used as described above. In this case, as the spinning die of the spinning blown spinning device, the one shown in FIG. 6 can be used. The spinning die shown in FIG. 6 has a structure in which spinning nozzles A and spinning nozzles B are alternately arranged. From the spinning nozzle A, a resin that is a raw material of the elastic fiber is discharged. On the other hand, from the spinning nozzle B, a resin that is a raw material of the inelastic fiber is discharged.

  When the target stretchable nonwoven fabric has a single layer structure, the obtained web is subjected to an air-through hot air treatment to thermally bond the intersections of the fibers to obtain a fiber sheet. When the target stretchable nonwoven fabric has a multilayer structure, a non-elastic fiber web manufactured separately is laminated and then subjected to an air-through hot air treatment to obtain a fiber sheet.

  The fiber sheet obtained in this way is stretched in at least one direction to stretch the low-stretched inelastic fiber, and then the stretch of the fiber sheet is released to obtain the intended stretchable nonwoven fabric.

  The present invention is not limited to the embodiment. For example, the stretchable nonwoven fabric 10 of the above-described embodiment has a configuration in which the same or different substantially inelastic non-elastic fiber layers 2 and 3 are laminated on both surfaces of the elastic fiber layer 1. Instead, a two-layer structure in which an inelastic fiber layer is laminated on one surface of the elastic fiber layer may be used. When a stretchable nonwoven fabric having a two-layer structure is used as a constituent material of an absorbent article, particularly when used on a portion that touches the user's skin, the non-elastic fiber layer is used to face the wearer's skin. It is preferable from the viewpoints of touch and prevention of stickiness.

  In the method shown in FIG. 4, 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. And it can also extend | stretch in the state which pinched | interposed the fiber sheet 10A between both. That is, it can be stretched in a state of bottoming through the fiber sheet. In addition, the stretching step may be performed by the method described in JP-A-6-133998.

  Moreover, in the said manufacturing method, although 10 A of fiber sheets were extended | stretched in CD direction, it can also be extended to MD direction instead of or in addition to this.

  Further, in the above-described embodiment, a part of the constituent fibers of the non-elastic fiber layer enters the elastic fiber layer and / or a part of the constituent fibers of the elastic fiber layer enters the non-elastic fiber layer. However, the structure of the stretchable nonwoven fabric of the present invention is not limited to this.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.

[Example 1]
The stretchable nonwoven fabric shown in FIG. 1 was manufactured using the apparatus shown in FIG. First, a low-stretch non-elastic short fiber (core-sheath type composite fiber having a core of PET and a sheath of PE) having a diameter of 17 μm, a fiber length of 44 mm, and an elongation of 150% is supplied to the card machine, and the non-elastic fiber web comprising the card web 3 ′ was formed. The basis weight of the web 3 ′ was 10 g / m ² . An elastic fiber web 1 'was laminated on the non-elastic fiber web 3'.

The elastic fiber web 1 ′ was formed by the following method. A SEBS resin having a weight average molecular weight of 50,000, MFR15 (230 ° C., 2.16 kg), storage elastic modulus G′2 × 10 ⁶ Pa, tan δ 0.06 was used as the elastic resin. This block copolymer contains 20% by weight of styrene as the polymer block A and 80% by weight of ethylene-butylene as the polymer block B. Using an extruder, the molten resin was extruded from a spinning nozzle at a die temperature of 310 ° C., and an elastic fiber web was formed 1 ′ on the net by a spinning blow method. The diameter of the elastic fiber was 32 μm. The basis weight of the web 1 ′ was 40 g / m ² .

On the elastic fiber web 1 ′, a non-elastic fiber web 2 ′ made of the same non-elastic short fibers as described above was laminated. The basis weight of the web 2 ′ was 10 g / m ² .

The laminate of these three-layer webs was introduced into a heat treatment machine, and hot air was blown by an air-through method to perform heat treatment. The heat treatment conditions were an on-net temperature of 140 ° C., a hot air flow rate of 2 m / second, a spraying pressure of 0.1 kg / cm ² , and a spraying time of 15 seconds. By this heat treatment, a fiber sheet 10B in which three layers of webs were integrated was obtained.

Next, hot embossing was applied to the fiber sheet 10B. The hot embossing was performed using an embossing device provided with an embossed convex roll and a flat metal roll. As the embossed convex roll, a dot-shaped convex roll having a large number of convex portions with a pitch in the CD direction (interval between adjacent joint row R ₁ ) of 2.0 mm was used. The temperature of each roll was set to 110 ° C. By this hot embossing, a fiber sheet 10A in which the joints were formed in a regular pattern was obtained.

The fiber sheet 10A was stretched. The stretching process was performed using a stretching apparatus including a pair of concavo-convex rolls in which large diameter portions and small diameter portions were alternately formed in the axial length direction. The pitch between the large diameter part and the small diameter part of one uneven | corrugated roll was 2.0 mm, respectively. The fiber sheet 10A was stretched in the CD direction by a stretching process. As a result, a nonwoven fabric having a basis weight of 60 g / m ² that expands and contracts in the CD direction was obtained. In addition, the conveyance speed of each of the above steps was 10 m / min.

[Examples 2 to 4]
A stretchable nonwoven fabric 10 shown in FIG. 1 was produced. The card web is supplied with low-stretched inelastic short fibers (core-sheath type composite fiber having a core of PET and a sheath of PE) having a fiber diameter and elongation shown in Table 1 and a fiber length of 44 mm, and the card web. Formed. This card web was introduced into a heat treatment machine, and hot air was blown by an air-through method to perform heat treatment, and the constituent fibers were temporarily fused. The heat treatment condition was an on-net temperature of 137 ° C. By this heat treatment, an inelastic fiber web 3 ′ having a basis weight of 10 g / m ² on which the constituent fibers were temporarily fused was obtained. On this non-elastic fiber web 3 ′, an elastic fiber web 1 ′ made of continuous fibers was directly laminated.

The elastic fiber web 1 ′ was produced in the same manner as in Example 1. The diameter of the elastic fiber was 32 μm, and the basis weight of the web 1 ′ was 40 g / m ² .

On the elastic fiber web 1 ′, a non-elastic fiber web 2 ′ made of the same non-elastic short fibers as described above was laminated. The basis weight of the web 2 ′ was 10 g / m ² . The constituent fibers of the web 2 'are not temporarily fused.

The laminate of these three-layer webs was introduced into a heat treatment machine, and heat treatment was performed by blowing hot air using an air-through method. The heat treatment conditions were an on-net temperature of 140 ° C., a hot air flow rate of 2 m / second, a spraying pressure of 0.1 kPa, and a spraying time of 15 seconds. The air permeability of the net was 500 cm ³ / (cm ² · s). By this heat treatment, a fiber sheet 10B in which three layers of webs were integrated was obtained.

  Next, hot embossing was applied to the fiber sheet 10B. The hot embossing was performed using an embossing device provided with an embossed convex roll and a flat metal roll. As the embossed convex roll, a dot-shaped convex roll having a large number of convex portions with a pitch of 2.0 mm in both the CD direction and the MD direction was used. The temperature of each roll was set to 120 ° C. By this hot embossing, a fiber sheet 10A in which the joints were formed in a regular pattern was obtained. 10 A of this fiber sheet was wound up and it was set as the nonwoven fabric original fabric.

The fiber sheet 10A was drawn out from the original fabric and subjected to stretching. The stretching process was performed using a stretching apparatus including a pair of tooth gap rolls in which teeth and tooth bottoms were alternately formed in the axial length direction. The pitch between teeth and the bottom of each tooth was 2.0 mm (the pitch P between teeth in the meshed state was 1.0 mm). The pushing amount of the upper and lower tooth gap rolls was adjusted, and the fiber sheet 10A was stretched in the MD direction at a stretch ratio of 3.0. As a result, a stretchable nonwoven fabric 10 having a basis weight of 60 g / m ² that stretches in the MD direction was obtained.

Example 5
A stretchable nonwoven fabric 10 shown in FIG. 1 was produced. The elastic fiber web 1 ′ was formed by the following method. As a block copolymer, SEPS resin (weight average molecular weight 50000, MFR 60 g / min (230 ° C., 2.16 kg), styrene-ethylene-propylene-styrene block copolymer, storage elastic modulus G′5 × 10 ⁵ Pa, An elastomer consisting of tan δ 0.045) was used. This block copolymer contains 30% by weight of styrene as the polymer block A and 70% by weight of ethylene-propylene as the polymer block B. Using an extruder, the melted block copolymer was extruded from a spinning nozzle at a die temperature of 290 ° C., and an elastic fiber web 1 ′ composed of continuous fibers was formed on the net by a spinning blow method. The diameter of the elastic fiber was 20 μm. The elastic fiber web 1 'was good in terms of texture. The basis weight of the web 1 ′ was 15 g / m ² . Except this, it carried out similarly to Example 2, and obtained the elastic nonwoven fabric 10 of basic weight 35g / m < ² > which expands-contracts in MD direction.

[Comparative Example 1]
A stretchable nonwoven fabric was produced in the same manner as in Example 1 except that inelastic short fibers having an elongation of 40% were used as constituent fibers of the inelastic fiber web instead of the low-stretched inelastic short fibers.

[Comparative Example 2]
As the block copolymer, HYBRAR (registered trademark) 7311, which is a styrene-vinylisoprene block copolymer manufactured by Kuraray Co., Ltd., was used. This block copolymer contains 12% by weight of styrene and 88% by weight of vinyl isoprene. This block copolymer had a storage elastic modulus G ′ of 1.0 × 10 ⁶ and a tan δ of 0.3. Except for this, an elastic nonwoven fabric was obtained in the same manner as in Comparative Example 1.

[Comparative Example 3]
As the block copolymer, TUFTEC (registered trademark) H1031 which is a styrene-ethylene-butylene-styrene block copolymer manufactured by Asahi Kasei Chemicals Corporation was used. This block copolymer contains 30% by weight of styrene and 70% by weight of ethylene-butylene. This block copolymer had a storage elastic modulus G ′ of 1.0 × 10 ⁷ and a tan δ of 0.03. Except for this, an elastic nonwoven fabric was obtained in the same manner as in Comparative Example 1.

[Evaluation]
The properties of the stretchable nonwoven fabric obtained in the examples and comparative examples are shown in Table 1 below. The measurement method for each item in the table is as follows.

<Maximum fiber diameter and minimum fiber diameter of inelastic fibers>
The surface of the stretchable nonwoven fabric (5 mm x 5 mm) is observed with a scanning electron microscope (SEM), the average value of the five large fiber diameters is the maximum fiber diameter, and the average of the five small fiber diameters is the minimum fiber The diameter.

<Fusing point strength of non-elastic fiber before drawing, strength at 100% elongation, and fiber elongation>
The measurement was performed according to the measurement method described above.

<Thickness>
The stretchable nonwoven fabric was allowed to stand for 2 days or more in an environment of 23 ± 2 ° C. and 60% RH with no load, and the thickness was determined by the following method. The stretchable nonwoven fabric was sandwiched between flat plates with a load of 0.5 cN / cm ^{2, and} the cross section was observed with a microscope at a magnification of 25 to 200 times under that condition, and the average thickness of each layer was determined. The total thickness was determined from the distance between the flat plates. Regarding the fiber penetration, the midpoint of mutual penetration was defined as the thickness.

<Bending rigidity>
The measurement was performed according to the method described above using HOM-3 manufactured by Daiei Scientific Instruments.

<Maximum strength, maximum elongation, strength at 100% elongation, 50% return strength, residual strain>
A rectangular test piece having a size of 50 mm in the stretching direction of the stretchable nonwoven fabric and 25 mm in the direction perpendicular thereto was cut out. The test piece was attached to Orientec Tensilon RTC1210A. The distance between chucks was 25 mm. The test piece was stretched at a speed of 300 mm / min in the stretching direction of the nonwoven fabric, and the load at that time was measured. The load at the maximum point at that time was defined as the maximum strength. Moreover, when the length of the test piece at that time was set to B and the length of the original test piece was set to A, {(BA) / A} * 100 was made into the maximum elongation (%). Further, a 100% elongation cycle test was performed, and the strength at 100% elongation was determined from the load at 100% elongation. Subsequently, it was made to shrink | contract at the same speed to the return direction (shrinkage direction), and it was set as the state extended 50%. The load at that time was recorded, and the return strength was 50%. Furthermore, after 100% elongation, the ratio of the length that did not return when returning to the origin at the same speed was measured, and the value was taken as the residual strain. The maximum strength was also measured for the fiber sheet A, which is the raw fabric of the stretchable nonwoven fabric, by the same method.

<Feel>
The surface of the stretchable nonwoven fabric was directly touched with the palm of the hand, and the touch was determined according to the following criteria. There is a feeling of resistance (rough feeling): x, there is a little resistance: Δ, there is no resistance, there is a little smooth feeling: ○, there is no resistance, there is a smooth feeling: ◎. Judgment was made by three people, and if two or more people had the same opinion, the opinion was taken as the judgment result. If the three people were different opinions, the middle opinion was taken as the judgment result.

  As is clear from the results shown in Table 1, the nonwoven fabrics of the examples had higher strengths at 100% elongation and residual strains at the same level as the nonwoven fabrics of the comparative examples, and higher than the nonwoven fabrics of the comparative examples. It can be seen that it has strength and high elongation. When a disposable diaper was produced using the nonwoven fabric of the example for the exterior, this diaper was soft to the touch and highly breathable, had a characteristic that it was easy to be stretched enough to stretch, and rubber marks were difficult to stick because it was tightened on the entire surface. .

  In addition, when SEM observation of the cross section of the nonwoven fabric of an Example and a comparative example was carried out, in any nonwoven fabric, the constituent fiber of an elastic fiber layer and the constituent fiber of a non-elastic fiber layer are heat-sealed, These fiber layers are It was fully bonded. Moreover, it was confirmed that some of the constituent fibers of the non-elastic fiber layer have entered the thickness direction of the elastic fiber layer. The constituent fibers of the elastic fiber layer maintained the fiber form. Furthermore, in the nonwoven fabric of an Example, the thickness of the nonelastic fiber changed periodically. On the other hand, in the nonwoven fabric of the comparative example, many fractures of the fusion point of the inelastic fiber were observed.

Drawing 1 is a mimetic diagram showing the section structure of one embodiment of the elastic nonwoven fabric of the present invention. FIG. 2 is a schematic view showing a preferred apparatus used for producing the stretchable nonwoven fabric shown in FIG. FIG. 3 is a plan view showing an example of a fiber sheet to be stretched. 4A is a cross-sectional view taken along the line aa in the CD direction of the fiber sheet shown in FIG. 3, and FIG. 4B is a diagram of the deformed state (stretched state) between the concavo-convex rolls. Sectional drawing corresponding to (a), FIG.4 (c) is sectional drawing in alignment with the cc line | wire of the CD direction of the fiber sheet shown in FIG.3, FIG.4 (d) is the state deform | transformed between the uneven | corrugated rolls ( FIG. 5 is a cross-sectional view corresponding to FIG. FIG. 5 is a schematic diagram showing a state in which the inelastic fiber is drawn. FIG. 6 is a schematic diagram showing an example of the structure of a spinning die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic fiber layer 2 Inelastic fiber layer 3 Inelastic fiber layer 4 Joining part 10A Fiber sheet 10 Elastic nonwoven fabric

Claims (14)

An elastic fiber and a non-elastic fiber having a non -uniform thickness along the longitudinal direction, the elongation of the raw fiber of the non-elastic fiber is 120 to 800%, and the thickness of the non-elastic fiber is periodically A stretchable nonwoven fabric that changes and has a thickness of 2 to 15 μm in the thinnest part and 10 to 30 μm in the thickest part.   The stretchable nonwoven fabric according to claim 1, wherein a non-elastic fiber layer including the non-elastic fiber is disposed on at least one surface of the elastic fiber layer including the elastic fiber.   The stretchable nonwoven fabric according to claim 1, further comprising an elastic fiber layer including the elastic fiber and the non-elastic fiber.   The stretchable nonwoven fabric according to any one of claims 1 to 3, wherein a distance between the thickest portion and the thickest portion adjacent thereto is 0.5 to 2.5 mm.   The stretchable nonwoven fabric according to any one of claims 1 to 4, wherein the inelastic fiber is a short fiber made of a composite fiber. The stretchable nonwoven fabric according to any one of claims 1 to 5 , wherein the non-elastic fiber has an inter-fiber fusion point strength higher than the strength at 100% elongation of the non-elastic fiber. The stretchable nonwoven fabric according to any one of claims 1 to 6 , wherein the fibers are heat-sealed by an air-through method. The non-elastic fiber is formed by stretching the raw material of the stretchable nonwoven fabric to stretch the raw fiber of the non-elastic fiber,
The stretchable nonwoven fabric according to any one of claims 1 to 7 , wherein a ratio of a tensile strength of the stretchable nonwoven fabric to a tensile strength of an original fabric of the stretchable nonwoven fabric is 0.3 to 0.99. Having the elastic fiber layer and the non-elastic fiber layer disposed on at least one surface thereof;
The elastic fiber contained in the elastic fiber layer is a polymer block A mainly composed of 10 to 50% by weight of an aromatic vinyl compound, and a polymer block B mainly composed of a repeating unit represented by the following formula (1). A block copolymer consisting of
The block copolymer has a storage elastic modulus G ′ of dynamic viscoelasticity measured at 20 ° C. and a frequency of 2 Hz of 1 × 10 4 to 8 × 10 6 Pa, and a dynamic viscosity measured at the same temperature and the same frequency. The stretchable nonwoven fabric according to claim 2, wherein the elastic dynamic loss tangent tan δ value is 0.2 or less.

The stretchable nonwoven fabric according to claim 9, wherein the polymer block B further contains 20 mol% or less of a repeating unit represented by the following formula (2).

The stretchable nonwoven fabric according to claim 9 or 10 , wherein the basic type of the block copolymer is ABA. The stretchable nonwoven fabric according to any one of claims 9 to 11 , wherein the elastic fibers are continuous fibers. It is a manufacturing method of the elastic nonwoven fabric according to claim 2,
A web containing low-stretch non-elastic fibers having an elongation of 80 to 800% is disposed on at least one surface of the web containing elastic fibers;
For these webs, in a state where they are not integrated, an air-through hot air treatment is performed to thermally fuse the intersections of the fibers to obtain a fiber sheet in which these webs are integrated,
A method for producing a stretchable nonwoven fabric, wherein the fiber sheet is stretched in at least one direction to stretch the low-stretched inelastic fiber, and then the stretching of the fiber sheet is released. It is a manufacturing method of the elastic nonwoven fabric according to claim 3,
Applying an air-through hot air treatment to a web containing elastic fibers and low-stretch inelastic fibers with an elongation of 80 to 800% to obtain a fiber sheet by thermally fusing the intersections of the fibers,
A method for producing a stretchable nonwoven fabric, wherein the fiber sheet is stretched in at least one direction to stretch the low-stretched inelastic fiber, and then the stretching of the fiber sheet is released.

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