JP4535984B2 - Method for manufacturing concavo-convex structure - Google Patents

Description

  The present invention relates to a method for manufacturing a concavo-convex structure.

  Conventionally, a three-dimensional shaped non-woven fabric with a three-dimensional shape of the surface of a non-woven fabric, which is usually flat, is incorporated into an absorbent article, for example, to reduce the contact between the wearer's skin and the non-woven fabric to prevent stuffiness and rash. There have been proposals such as increasing the amount of deformation in the thickness direction to make the skin fit softly. For example, it has been proposed to use a multi-layered nonwoven fabric as a surface material of an absorbent article (see Patent Documents 1 and 2). In addition, a composite non-woven fabric having a concavo-convex structure is obtained by overlapping a latent shrinkable nonwoven sheet and a sheet-like material having a heat shrinkability smaller than that of the sheet, partially bonding each other, and then causing shrinkage by heat treatment. It has also been proposed to obtain (see Patent Document 3). In these nonwoven fabrics, a highly shrinkable sheet and a sheet that does not easily shrink are combined, and wrinkles and irregularities are formed by utilizing the difference in heat shrinkage between them.

  Thus, the three-dimensional sheet proposed so far has a configuration of two or more layers having different shrinkage rates, and is obtained by performing heat shrinkage treatment. Therefore, it is difficult to obtain a product with a low basis weight due to its configuration and manufacturing method. Further, since the manufacturing method is complicated, the productivity is low and the cost is high.

  Further, the surface layer of the absorbent article is composed of a liquid-permeable base material and a continuous filament layer provided on the surface of the base material, and the continuous filament layer is raised on the surface side. The thing which formed the loop part of the continuous filament is proposed (refer patent document 4). However, since this surface layer is obtained by subjecting the base material to heat shrink treatment or shrinking an elastic member fixed to the surface layer in an expanded state, it is difficult to obtain a material with a low basis weight, or the manufacturing method is complicated. Therefore, the productivity is low and the cost is high.

Japanese Patent Laid-Open No. 6-128553 Japanese Patent Laid-Open No. 9-111631 Japanese Patent Laid-Open No. 62-141167 JP 2002-65736 A

  Accordingly, an object of the present invention is to provide a method for producing a concavo-convex structure that can eliminate the various drawbacks of the above-described prior art.

  The present invention includes a heat-extensible long fiber whose length is extended by heating, and after the fiber layer in which the heat-extensible long fiber is oriented in one direction is partially joined to a base material layer, An uneven structure in which the heat-extensible long fibers are heated and stretched so that the heat-extensible long fibers form convex portions in portions other than the joint portions with the base material layer and the joint portions are concave portions. The object is achieved by providing a method for producing a concavo-convex structure, which obtains a body.

  Moreover, this invention provides the absorbent article which contains the said uneven structure body and this uneven structure body as at least one part of a surface material, an absorber, or an exterior material.

  According to the method for manufacturing a concavo-convex structure of the present invention, a low-density concavo-convex structure having a three-dimensional concavo-convex shape can be manufactured at low cost without using special manufacturing equipment. According to the concavo-convex structure and absorbent article of the present invention, excellent performance derived from the characteristics of the concavo-convex structure having a three-dimensional concavo-convex shape and low density is exhibited.

The present invention will be described below based on preferred embodiments with reference to the drawings.
The outline of the manufacturing process in one Embodiment of the manufacturing method of the uneven structure of this invention is shown by FIG. In the present embodiment, as shown in FIG. 1, the tow 11 containing the heat-extensible long fibers is opened by the opening device 1 and the spread tow 2 is expanded, and the heat-extensible long fibers 21. And the heat-extensible long fiber 21 is used as a fiber layer oriented in one direction (machine direction).

The fiber opening device 1 shown in FIG. 1 continuously pulls out the tow 11 from the tow raw fabric 10 in a stacked and compressed state, and sequentially opens the drawn tow 11 with a plurality of fiber opening machines (banding jets) 12 to 14. A fiber treatment is performed, whereby the fibers constituting the tow 11 can be dispersed substantially uniformly in the width direction. A guide 15 is provided between the spreaders 12 and 13 and the tow 11 is once sent upward and then lowered. A pretensioning roll 16 and a blooming roll 17 are provided between the spreaders 13 and 14. A delivery roll 18 is provided downstream of the spreader 14.
The spreaders 12 to 14 are devices that spread air by blowing air to open the tow being conveyed. The pretensioning roll 16 includes a pair of rolls that nip the tow 11 opened by the spreaders 12 and 13 and feed the tow 11 at a predetermined speed. The blooming roll 17 includes a groove roll 17a and an anvil roll 17b whose peripheral surface is made of rubber. A speed difference is provided between the pre-tensioning roll 16 and the tow 11 can be easily opened. is doing. The delivery roll 18 includes a pair of rolls that supply the downstream side of the spread tow 2 that has finished opening while maintaining a predetermined tension.

  In the present embodiment, the fiber opening tow 2 in which the constituent fibers are dispersed substantially uniformly in the width direction by the fiber opening process by the fiber opening device 1 has been continuously conveyed by a known conveyance mechanism as shown in FIG. Laminated with the belt-like base material layer 3, the spread fiber tow 2 and the base material layer 3 are sent to the heat embossing device 4, where heat embossing is performed. The heat embossing device 4 includes a pair of rolls 41 and 42. The roll 41 is a smooth roll having a smooth peripheral surface. On the other hand, the roll 42 is a sculpture roll in which a convex portion for forming a joint portion and a concave portion for forming a non-joint portion are formed on the peripheral surface thereof. Each roll 41, 42 can be heated to a predetermined temperature.

  The opening tow (fiber layer) 2 in the present embodiment includes a heat-extensible long fiber whose length is increased by heating (hereinafter, this fiber is referred to as a heat-extensible long fiber) as its constituent fibers. The expression “including heat-extensible long fibers” includes a case of 100% by weight of heat-extensible long fibers. Examples of the heat-extensible long fibers include fibers that are changed by changing the crystalline state of the resin by heating, or fibers that have been crimped and have an apparent length that is released by crimping. . In the present invention, the heat-extensible long fiber particularly preferably used has a first resin component having an orientation index of 40% or more, a melting point or softening point lower than the melting point of the first resin component, and an orientation index of 25. % Of the second resin component, and the second resin component is a composite fiber in which at least a part of the fiber surface is continuously present in the length direction (hereinafter, this fiber is referred to as a heat-extensible composite fiber). Can be mentioned.

The heat embossing is preferably performed at a temperature lower than the elongation start temperature of the heat-extensible long fiber contained in the spread tow (fiber layer) 2, and the spread tow (fiber layer) 2 has the heat stretchability. When the composite fiber is included (including a case where the heat-extensible composite fiber is 100%), the heat embossing is performed at a temperature higher than the melting point of the low-melting component and lower than the melting point of the high-melting component. It is preferable.
By this heat embossing, the spread tow 2 and the base material layer 3 are partially crimped or heat-sealed to form the joint portion 51.

Joining of the spread tow 2 and the base material layer 3 is, for example, as seen from a direction perpendicular to the surface of the composite 5 of the spread tow 2 and the base material layer 3 as in the joining pattern shown in FIG. The heat-extensible long fibers 21 are reliably fixed before and after the non-joining portion 52, so that a large number of non-joining portions 52 surrounded by the joining portion 51 are generated. The convex portions 71 formed of fibers are preferably spherical or dome-shaped, and an uneven structure having excellent appearance, abrasion resistance from various directions, and touch is obtained. In the joining pattern shown in FIG. 2, a large number of substantially circular non-joining portions 52 having an area of about 3 to 350 mm ² are formed in a staggered manner, and the other portions are joining portions 51.

3 (a) to 3 (c) show another example of a joining pattern for joining the spread tow 2 and the base material layer 3 so that a large number of non-joining parts 52 surrounded by the joining part 51 are generated. FIG.
In addition, the bonding of the fiber opening tow 2 and the base material layer 3 has an area instead of a bonding pattern such as shown in FIG. 2 or FIG. It can also be performed with a bonding pattern in which bonding portions such as circles, triangles, rectangles, and other shapes of about 1 to 400 mm ² are formed in a dispersed manner. In addition, the ratio of the area of the joint portion 51 to the area of the opened tow (fiber layer) 2 is 1 to 20%, and more preferably 2 to 10%, so that a three-dimensional uneven shape can be effectively formed. To preferred.

  The composite 5 produced by partially bonding the opened tow 2 and the base material layer 3 is conveyed to a hot air spraying device 6. In the hot air spraying device 6, the composite 5 is subjected to air through processing. That is, the hot air blowing device 6 is configured such that hot air heated to a predetermined temperature penetrates the composite 5 in the thickness direction.

  The air-through process is performed at a temperature at which the heat-extensible long fibers in the composite 5 are elongated by heating. Moreover, it is necessary to carry out at the temperature below melting | fusing point of a heat | fever extensible long fiber. When the heat-extensible long fiber is a composite fiber composed of a high-melting component and a low-melting component (for example, in the case of the above-described heat-extensible composite fiber), the melting point of the component constituting the composite fiber is less than the melting point of the high-melting component It is necessary to carry out at the temperature.

By this air-through process, the heat-extensible long fibers existing in the portion other than the joint portion 51 are elongated. Since the heat-extensible long fiber 21 is fixed to the base material layer 3 at the joint portion 51, it is the portion between the joint portions 51 that extends. And since the part of the heat-extensible long fiber 21 is being fixed to the joining part 51, the elongation of the extended heat-extensible long fiber loses its place in the plane direction of the composite 5, and the composite It moves in the thickness direction of the body 5. As a result, convex portions 71 are formed between the joint portions 51. And the junction part 51 becomes a recessed part relatively. In this way, the intended concavo-convex structure 7 is obtained.
In the obtained concavo-convex structure 7, as shown in FIGS. 4 and 5, the elongated heat-extensible long fibers 21 swell in the direction away from the base material layer 3 to form a convex portion 71. Inside the portion 71, a cavity is formed between the heat-extensible long fibers 21 and the base material layer 3.
Non-heat-extensible fibers may be mixed in the opened tow (fiber layer) 2, and a layer made of non-heat-extensible fibers is laminated on the opened tow (fiber layer) 2 and then opened. The tow (fiber layer) 2 and the base material layer 3 may be partially joined in a state where a layer made of non-heat-extensible fibers is interposed therebetween. By doing so, fibers with different degrees of curvature can be generated inside the convex portion 71, and a void or fiber density gradation can be formed inside the convex portion, or a convex portion 71 without a cavity can be formed. It can also be made.

As is apparent from the above description, the concavo-convex structure 7 manufactured by the manufacturing method of the present embodiment includes the convex portion 71 formed by extending the heat-extensible long fiber at a portion other than the joint portion, and the convex portion. As a result of the occurrence of 71, it has a joint 51 that is relatively concave. Therefore, the concavo-convex structure 7 has a three-dimensional concavo-convex shape, and since it is not necessary to shrink the base material layer 3 to form the convex portion 71, it has a low density (low basis weight). Good liquid permeability and air permeability. Moreover, said manufacturing method is only what combined the heat embossing and the air through method which are very general methods in the manufacturing method of a nonwoven fabric, and does not include a special process. Therefore, the manufacturing process is simple and the manufacturing efficiency is high.
Further, since the heat-extensible long fibers constituting the fiber opening tow (fiber layer) 2 are oriented in the machine direction (MD) direction during production, the heat-extensible long fibers forming the convex portion 71 are bonded to each other. The heat-extensible continuous fibers forming the convex portions 71 are relatively easy to move. Therefore, it is excellent in absorbing highly viscous liquids such as soft stool when used as a surface material, a second sheet, a part of an absorbent body, etc., and large dust when used as a cleaning sheet. It has excellent collection ability. In the case of using a composite fiber containing a high-melting component and a low-melting component, particularly the above-described heat-extensible composite fiber, the intersection between the heat-extensible long fibers becomes relatively easy to be heat-sealed. In this case, the convex portion 71 rich in repulsive force is obtained, and cushioning properties (thickness recovery properties) and the like are improved.

  As described above, the open tow (fiber layer) 2 used for manufacturing the concavo-convex structure 7 includes a heat-extensible long fiber (including a case where the heat-extensible long fiber is composed of 100% by weight). . When the spread tow (fiber layer) 2 includes a heat-extensible long fiber and other fibers, the other fibers contained in the spread tow (fiber layer) 2 are based on the thermal elongation expression temperature of the heat-extensible long fiber. Examples thereof include fibers made of a thermoplastic resin having a high melting point, and fibers that do not inherently have heat fusibility (for example, natural fibers such as cotton and pulp, rayon and acetate fibers). The other fibers are preferably contained in the spread tow (fiber layer) 2 by 5 to 50% by weight, more preferably 20 to 30% by weight. On the other hand, the heat-extensible long fiber is contained in the spread tow (fiber layer) 2 in an amount of 50 to 95% by weight, particularly 70 to 95% by weight, from which a three-dimensional uneven shape can be effectively formed. preferable. Particularly preferably, the spread tow (fiber layer) 2 is made of a heat-extensible composite fiber from the viewpoint that a three-dimensional uneven shape can be more effectively formed.

  The details of the above-described heat-extensible composite fiber will be described. The heat-extensible composite fiber is preferably produced by a high-speed melt spinning method. As shown in FIG. 6, the high-speed melt spinning method is performed by using a spinning device provided with two systems of extrusion devices 101 and 102 including extruders 101 </ b> A and 102 </ b> A and gear pumps 101 </ b> B and 102 </ b> B, and a spinneret 103. The resin components melted and measured by the extruders 101A and 102A and the gear pumps 101B and 102B are merged in the spinneret 103 and discharged from the nozzle. As the shape of the spinneret 103, an appropriate shape is selected according to the shape of the target composite fiber. A winding device 104 is installed immediately below the spinneret 103, and the molten resin discharged from the nozzle is taken down at a predetermined speed. The take-up speed of the spun yarn in the high speed melt spinning method is generally 2000 m / min or more. The upper limit value of the take-up speed is not particularly limited, and it is now possible to take up at a speed exceeding 10,000 m / min.

  The first resin component in the heat-extensible conjugate fiber is a component that maintains the strength of the conjugate fiber, and the second resin component is a component that exhibits heat-fusibility. The first resin component preferably has an orientation index of 40% or more, more preferably 50% or more. On the other hand, the second resin component has an orientation index of preferably 25% or less, more preferably 20% or less. The orientation index is an index of the degree of orientation of the polymer chain of the resin constituting the fiber. And when the orientation index of a 1st resin component and a 2nd resin component is each said value, a heat | fever extensible composite fiber comes to expand | extend by heating. In addition, it is possible to form a fusion point with high heat and low strength. In order to achieve the orientation index as described above for each resin component in the heat-extensible conjugate fiber, for example, two types of resins having different melting points may be used, and the fiber may be formed by the high-speed melt spinning method.

  There is no particular limitation on the upper limit of the orientation index of the first resin component, and the higher the value, the better. However, if it is about 70%, a sufficiently satisfactory effect can be obtained. On the other hand, the lower limit of the orientation index of the second resin component is not particularly limited, and the lower the better, the better. However, if it is about 15%, a sufficiently satisfactory effect can be obtained.

The orientation index of the first resin component and the second resin component is expressed by the following formula (1), where A is the birefringence value of the resin in the heat-extensible conjugate fiber, and B is the intrinsic birefringence value of the resin. expressed.
Orientation index (%) = A / B × 100 (1)

  Intrinsic birefringence refers to birefringence in the state where the polymer polymer chains are perfectly oriented. The value is, for example, the first edition of “Plastic Materials in Molding”. Edited by Japan Society for Molding and Processing, Sigma Publishing, published on February 10, 1998).

The birefringence in the heat-extensible composite fiber is measured under polarization in a direction parallel to and perpendicular to the fiber axis by attaching a polarizing plate to an interference microscope. As the immersion liquid, a standard refraction liquid manufactured by Cargille is used. The refractive index of the immersion liquid is measured with an Abbe refractometer. From the interference fringe image of the composite fiber obtained by the interference microscope, the refractive index in the direction parallel and perpendicular to the fiber axis is obtained by the calculation method described in the following document, and the birefringence that is the difference between the two is calculated.
“Fiber structure formation in high-speed spinning of core-sheath type composite fiber”, page 408 (Journal of the Fiber Society, Vol. 51, No. 9, 1995)

  The heat-stretchable conjugate fiber has a stretch ratio of 0.5 to 20, particularly 3 to 10% at a temperature 10 ° C. higher than the melting point or softening point of the second resin component. It is preferable from the point obtained.

  In order to obtain a heat-extensible composite fiber having such a heat extension rate, after spinning the heat-extensible composite fiber, the composite fiber is subjected to heat treatment or crimping treatment and not subjected to drawing treatment. do it. The reason for measuring the thermal elongation rate at the above-mentioned temperature is that when the nonwoven fabric is manufactured by thermally fusing the intersections of the fibers, it is higher than the melting point or softening point of the second resin component and higher by about 10 ° C. It is because it is normal to manufacture in the range up to temperature.

  The thermal elongation rate is measured by the following method. Using a thermomechanical analyzer TMA-50 (manufactured by Shimadzu Corp.), parallel fibers are mounted at a distance between chucks of 10 mm, and a constant load of 0.025 mN / tex is applied, and a temperature increase rate of 10 ° C./min. Raise the temperature at. The change in the elongation rate of the fiber at that time is measured, and the elongation rate at a temperature 10 ° C. higher than the melting point or softening point of the second resin component is read to obtain the heat shrinkage rate.

  Appropriate conditions for the heat treatment performed after spinning are selected according to the types of the first and second resin components constituting the conjugate fiber of the present invention. For example, when the conjugate fiber of the present invention is a core-sheath type, the core component is polypropylene and the sheath component is high-density polyethylene, the heating temperature is preferably 50 to 120 ° C., particularly preferably 70 to 100 ° C., and the heating time Is preferably 10 to 500 seconds, more preferably 20 to 200 seconds. Examples of the heating method include hot air blowing and infrared irradiation.

  As the crimping process performed after spinning, it is convenient to perform mechanical crimping. There are two-dimensional and three-dimensional forms of mechanical crimps, and there are three-dimensional manifested crimps found in eccentric core-sheath composite fibers and side-by-side composite fibers. In the present invention, any type of crimping may be performed. Mechanical crimp can be accompanied by heat. In that case, the heat treatment and the crimping treatment are performed simultaneously.

  In the crimping process, the fiber may be slightly stretched, but such stretching is not included in the stretching process referred to in this specification. The drawing treatment referred to in this specification refers to a drawing operation with a draw ratio of about 2 to 6 times that is usually performed on undrawn yarn.

  When the opening tow (fiber layer) 2 includes the heat-extensible composite fiber, the uneven shape becomes remarkable and the strength of the obtained uneven structure 7 is also increased.

  As the heat-extensible composite fiber, a core-sheath type or a side-by-side type can be used. As the core-sheath type heat-extensible composite fiber, a concentric type or an eccentric type can be used. In particular, the core-sheath type is preferable. In this case, it is preferable that the first resin component constitutes a core and the second resin component constitutes a sheath from the viewpoint of increasing the thermal elongation rate of the thermally extensible composite fiber. There is no restriction | limiting in particular in the kind of 1st resin component and 2nd resin component, What is necessary is just resin with fiber formation ability. In particular, the difference between the melting points of the two resin components, or the difference between the melting point of the first resin component and the softening point of the second resin component is 10 ° C. or more, particularly 20 ° C. or more. This is preferable because it can be performed. When the heat-extensible conjugate fiber is a core-sheath type, a resin having a melting point of the core component higher than the melting point or softening point of the sheath component is used. As a preferable combination of the first resin component and the second resin component, as the second resin component when the first resin component is polypropylene (PP), high-density polyethylene (HDPE), low-density polyethylene (LDPE), Examples include linear low density polyethylene (LLDPE), ethylene propylene copolymer, and polystyrene. When a polyester resin such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) is used as the first resin component, polypropylene (PP) is added as the second component in addition to the above-described example of the second resin component. And copolyester. Furthermore, examples of the first resin component include polyamide-based polymers and two or more types of copolymers of the first resin component described above, and examples of the second resin component include two or more types of the second resin component described above. Copolymers are also included. These are appropriately combined. Of these combinations, it is preferable to use polypropylene (PP) / high density polyethylene (HDPE). This is because the non-woven fabric can be easily manufactured because the difference in melting point between both resin components is in the range of 20 to 40 ° C. In addition, since the specific gravity of the fiber is low, a nonwoven fabric that is lightweight and excellent in cost and can be incinerated and discarded with a low heat quantity is obtained.

  The melting point of the first resin component and the second resin component was determined by using a differential scanning thermal analyzer DSC-50 (manufactured by Shimadzu Corporation) and performing thermal analysis of a finely cut fiber sample (sample mass 2 mg) at a heating rate of 10 ° C. / The melting peak temperature of each resin is measured and defined by the melting peak temperature. When the melting point of the second resin component cannot be clearly measured by this method, the temperature at which the second resin component is fused to such an extent that the fiber fusion point strength can be measured as the temperature at which the second resin component begins to flow. Is the softening point.

  The ratio (weight ratio) between the first resin component and the second resin component in the heat-extensible composite fiber is preferably 10:90 to 90: 10%, particularly 30:70 to 70: 30%. Within this range, the mechanical properties of the fiber are sufficient, and the fiber can withstand practical use. Further, the amount of the fusion component is sufficient, and the fibers are sufficiently fused.

  An appropriate value is selected as the thickness of the heat-extensible conjugate fiber depending on the specific use of the conjugate fiber. A general range is 1.0 to 10 dtex, particularly 1.7 to 8.0 dtex, from the viewpoints of fiber spinnability and cost, card machine passability, productivity, cost, and the like.

The base material layer 3 to be bonded to the opened tow (fiber layer) 2 does not expand at a temperature at which the heat-extensible long fibers start to expand. The material that can be used as the base material layer 3 can be appropriately selected according to the use of the concavo-convex structure, for example, the surface in the field of disposable hygiene articles such as disposable diapers, sanitary napkins, panty liners, incontinence pads, etc. When used as a sheet, a second sheet (sheet disposed between the top sheet and the absorber), a part of the absorber, etc., a liquid-permeable material (single layer or multilayer fiber sheet) is preferably used. For example, non-woven fabrics, papers, woven fabrics, composites thereof, and the like by various production methods can be mentioned. A baseboard used when a fiber material is piled to manufacture an absorbent core or a non-woven fabric to replace it can be used as the base material layer.
Moreover, although the back surface sheet | seat in the field | area of a disposable hygiene article can be used as a base material layer, the composite sheet etc., such as a resin film and a resin film, a nonwoven fabric, paper, a textile fabric, etc. can be used. When the base material layer is a poorly breathable material such as a resin film, instead of the air-through method described above, from the open tow (fiber layer) 2 side by far-infrared radiation or hot air blowing, The heat-extensible long fibers are stretched by other methods such as passing through a heating space. Moreover, it is preferable that resin which comprises a resin film is melting | fusing point below the elongation start temperature of a heat | fever extensible long fiber.

Further, as the base material layer, it is possible to use a fiber sheet made of thermoplastic fibers or mainly composed of thermoplastic fibers, which can be easily joined to the opened tow (fiber layer) by heat embossing, ultrasonic sealing, or the like. Preferably, the thermoplastic fiber includes polyethylene, polypropylene, polyester (such as PET), α-olefin copolymer, or a composite fiber of a combination thereof.
As a base material layer, what contains a heat-shrinkable fiber can also be used. By using a heat-shrinkable fiber layer containing heat-shrinkable fibers in the base material layer and heating and stretching the heat-extensible long fibers, the heat-shrinkable fiber layer is heat-shrinked at the same time or before and after, The three-dimensional convex part 7 can be formed. As the heat-shrinkable fiber, various known heat-shrinkable fibers that develop shrinkage by heat treatment at a predetermined temperature can be used. For example, those described in Patent Documents 1 and 2 can be used.

  The concavo-convex structure 7 produced in the present invention can be applied to various fields utilizing its concavo-convex shape, bulkiness and the like. For example, as described above, it can be used as a surface sheet, a second sheet (a sheet disposed between the surface sheet and the absorbent body), a part of the absorbent body, a back sheet, etc. in the field of disposable hygiene articles. It can also be used as an outer package (outer packaging material) for diapers and pants-type napkins. Furthermore, it is also suitably used as a personal wipe sheet, a skin care sheet, and an objective wiper.

When used for such applications, the concavo-convex structure according to the present invention preferably has a basis weight of 10 to 300 g / m ² , particularly 25 to 100 g / m ² . Moreover, it is preferable that the thickness is 0.7-10 mm, especially 1.5-5 mm. However, since the appropriate thickness varies depending on the application, it is appropriately adjusted according to the purpose.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the above-described embodiment, heat embossing that is embossing with heat is used to form the joint portion 51, but embossing without heat or ultrasonic embossing may be used instead. it can. Moreover, a junction part can also be formed with an adhesive agent.

It is a perspective view which shows the outline of a manufacturing process in one Embodiment of the manufacturing method of the uneven structure of this invention. It is a top view which shows an example of the joining pattern of a fiber layer and a base material layer. It is a top view which shows the other example of the joining pattern of a fiber layer and a base material layer. It is sectional drawing which shows the cross section of the direction in alignment with the machine direction (MD) at the time of manufacture of an uneven structure. It is sectional drawing which shows the cross section of the direction in alignment with the direction (CD) orthogonal to the machine direction at the time of manufacture of an uneven structure. It is a schematic diagram which shows the apparatus used for a high speed melt spinning method.

Explanation of symbols

1 Tow opening device 2 Opening tow (fiber layer)
DESCRIPTION OF SYMBOLS 3 Base material layer 4 Heat embossing apparatus 5 The composite of a fiber layer and a base material layer 51 Joining part 52 Non-joining part 6 Hot-air spraying apparatus 7 Uneven structure 71 Convex part

Claims (7)

  A heat-extensible long fiber comprising a heat-extensible long fiber whose length is extended by heating, the fiber layer in which the heat-extensible long fiber is oriented in one direction is partially joined to the base material layer, and then the heat-extensible long fiber. By heating and stretching the heat-extensible long fiber, a concavo-convex structure in which the convex portion is formed in a portion other than the joint portion with the base material layer and the joint portion is a concave portion is obtained. Manufacturing method of uneven structure.   The method for producing a concavo-convex structure according to claim 1, wherein a tow containing the heat-extensible long fibers is expanded to a predetermined width as the fiber layer.   The method for producing a concavo-convex structure according to claim 1 or 2, wherein the heat-extensible long fibers are composite fibers.   A heat-shrinkable fiber layer containing heat-shrinkable fibers is used as the substrate layer, and the heat-shrinkable fiber layer is heat-shrinked simultaneously with or before and after the heat-extensible long fibers are heated and stretched. Item 4. A method for producing an uneven structure according to any one of Items 1 to 3.   The joining of the fiber layer and the base material layer is performed so that a large number of non-joining portions surrounded by a joining portion are formed, and convex portions are formed on the heat-extensible long fibers in the non-joining portions. The manufacturing method of the uneven structure in any one of 1-4.   6. A concavo-convex structure produced by the method for producing a concavo-convex structure according to any one of claims 1 to 5. An absorbent article comprising the concavo-convex structure produced by the method for producing a concavo-convex structure according to any one of claims 1 to 5 as at least a part of a surface material, an absorber or an exterior material.

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