JP2013124428A - Laminated nonwoven fabric and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated nonwoven fabric having a good cushion touch, a large thickness and a high liquid passing speed, and a method for producing the same.SOLUTION: There is provided a laminated nonwoven fabric 10 comprising a first fiber layer 11 which includes thermoplastic fibers, is formed into an uneven shape and is thermally fused, and on which an unfused fiber web (second fiber web 14) which contains thermoplastic fibers to be a second fiber layer 12 is laminated. The first fiber layer 11 and the second fiber layer 12 laminated are heated by hot wind. Thus the fibers in the web are mutually and thermally fused to form the second fiber layer 12, and the fibers of the first fiber layer 11 and the fibers of the second fiber layer 12 are joined by thermal fusion.

Description

  The present invention relates to a laminated nonwoven fabric and a method for producing the same.

Absorbent articles such as sanitary napkins, panty liners, and disposable diapers have a two-layer sheet structure in which two-layer sheets are partially joined by a large number of joints according to their functions. The thing which arranged the part which raised in the shape is developed.
Patent Document 1 has an upper layer sheet and a lower layer sheet, and these two sheets are partially joined by heating and pressurization to form a large number of joined portions, and the upper layer sheet is surrounded by a plurality of joined portions. In such a region, a plurality of convex portions are formed so as to protrude toward the skin contact surface side. Thereby, the form of a convex part is maintained stably and it is supposed that it is excellent in the liquid return prevention property to the surface.

  Further, in Patent Document 2, a plurality of groove portions recessed in the thickness direction of the nonwoven fabric and a plurality of groove portions continuously formed on one surface side of the nonwoven fabric continuously formed along a predetermined direction are formed. A non-woven fabric having a plurality of convex portions adjacent to each of the plurality of groove portions and protruding to one surface side of the non-woven fabric is disclosed. The groove part in this nonwoven fabric is formed so that the basis weight is the lowest in the nonwoven fabric, the content of the horizontally oriented fibers is high, and the content of the vertically oriented fibers is low. And the side part of a convex-shaped part has the highest fabric weight in a nonwoven fabric, and the content rate of a longitudinally-oriented fiber is high. Thereby, it becomes easy to permeate | transmit predetermined liquids, such as excrement.

In the surface sheet of the absorbent article disclosed in Patent Document 1, the bonding method is heating and pressing or an adhesive, and the liquid passing speed is slowed by increasing the fiber density of the bonded portion.
Moreover, in the nonwoven fabric disclosed in Patent Document 2, the fiber density of the convex portion is higher than that of the groove portion, so that the liquid accumulated in the groove portion hardly flows to the convex portion side, and the liquid passing speed is slow. Moreover, since the convex part is not easily crushed by the pressure at the time of wearing, the cushioning property is low.

JP 2009-118920 A JP 2008-025081 A

  An object of the present invention is to provide a laminated nonwoven fabric having a good cushion feeling, a large thickness and a high liquid passage speed, and a method for producing the same.

  (1) In the present invention, an unfused fiber web containing thermoplastic fibers that are thermoplastic fibers to be a second fiber layer is laminated on a first fiber layer that is shaped into a concavo-convex shape and includes thermoplastic fibers, By heating the laminated first fiber layer and second fiber layer with hot air, the fibers of the fiber web are thermally fused to form a second fiber layer, and the fibers of the first fiber layer And a laminated nonwoven fabric in which the fibers of the second fiber layer are joined.

(2) The present invention has a convex portion protruding on the first surface side of the sheet-like laminated nonwoven fabric in plan view and a concave concave portion, and the plurality of convex portions are arranged so as to surround the concave portion. And the said convex part and the said recessed part are alternately and continuously arranged by each of the different direction which crosses planar view of this laminated nonwoven fabric, and have the uneven | corrugated shape by the said convex part and the said recessed part on the said 1st surface side. A fiber layer and a second fiber layer bonded along a second surface side opposite to the first surface side of the first fiber layer, and the fiber density of the recess is 0.01 to 0 A laminated nonwoven fabric having a thickness of 0.08 g / cm ³ is provided.

  (3) In the present invention, a first fiber web containing thermoplastic fibers is transported onto a support having an uneven shape and air permeability, and hot air is blown onto the first fiber web, the first fibers During the process of shaping the web following the uneven shape and conveying the first fiber web along the surface of the support, hot air is blown onto the first fiber web, and the support An air-through process in the previous stage to obtain a first fiber layer by fusing the fibers of the first fiber web while being shaped into a concavo-convex shape, and a second fiber web containing the first fiber layer and thermoplastic fibers And hot air is blown, and the fibers of the second fiber web are heat-sealed together along the shaped shape of the first fiber layer to obtain a second fiber layer and the first fiber layer and the first fiber layer. The latter stage of air that joins two fiber webs by heat-sealing To provide a method of manufacturing a laminated nonwoven fabric and a through process.

  (1) In the laminated nonwoven fabric of the present invention, the bonding between the first fiber layer and the second fiber layer is between the fibers in which the fibers of the first fiber layer and the fibers of the second fiber layer are in contact with each other by blowing hot air. Since the fiber layers are not pressed against each other due to the heat fusion, a gap is formed between the fibers at the bonding portion between the fiber layers as compared with the partial bonding of the sheet by the conventional heating and pressing. For this reason, even if it is a recessed part used as a junction part, a liquid passage time (liquid passage speed) is quick, and the bulky low-weight laminated nonwoven fabric can be provided. Furthermore, since the first nonwoven fabric has a concavo-convex shape, and the concavo-convex shape is maintained even by joining the fiber layers by blowing hot air, a laminated nonwoven fabric having a good cushion feeling (KES / WC value) at a low load is provided. can do.

(2) In the laminated nonwoven fabric of the present invention, the second fiber layer is joined along the second surface side of the first fiber layer having a concavo-convex shape, and the fiber density of the recesses is 0.01 to 0.08 g / cm. since it is ^3, the first fibrous layer is shaped into irregularities, a bulky and low basis weight, provides superior laminated nonwoven fast liquid permeable recess of liquid passing time (liquid passing speed) be able to. Moreover, since the laminated nonwoven fabric also has an uneven shape due to the uneven shape of the first fiber layer, it is possible to provide a laminated nonwoven fabric having a good cushion feeling (KES / WC value) under a low load.

  (3) In the method for producing a laminated nonwoven fabric of the present invention, the first fiber layer is shaped into a concavo-convex shape in the preceding air-through step, and an unfused fiber web is superimposed on the first fiber layer in this state, Since the air-through process is performed, a bulky low-weight laminated nonwoven fabric can be obtained. Furthermore, in this laminated nonwoven fabric, the first nonwoven fabric has a clear concavo-convex shape, and since the concavo-convex shape is maintained even by joining the fiber layers by blowing hot air, the cushion feeling (KES / WC value) at low load is maintained. A good laminated nonwoven fabric can be obtained.

1 is a partial cross-sectional perspective view schematically showing a preferred embodiment of a laminated nonwoven fabric according to the present invention. 3 is a drawing-substituting photograph in which a cross-section corresponding to the partial cross-sectional perspective view shown in FIG. 1 is imaged. It is the schematic block diagram which showed typically an example of the manufacturing apparatus of the laminated nonwoven fabric suitable for producing the laminated nonwoven fabric of this invention. It is the schematic block diagram which showed typically an example of the manufacturing apparatus of another laminated nonwoven fabric suitable for producing the laminated nonwoven fabric of this invention. It is typical sectional drawing explaining the measuring method of fiber orientation degree, and its partial enlarged view.

A preferred embodiment of the laminated nonwoven fabric according to the present invention will be described below with reference to FIGS. 1 and 2.
The laminated nonwoven fabric 10 of the present invention is preferably applied to a surface sheet of an absorbent article such as a sanitary napkin or a disposable diaper. The first surface side Z1 is used with the skin surface side of the wearer, and the second surface side. It is preferable to use Z2 on the absorber (not shown) side inside the article. Hereinafter, although it demonstrates considering the embodiment which uses the 1st surface side Z1 of the laminated nonwoven fabric 10 shown in drawing toward a wearer's skin surface, this invention is limited to this and is not interpreted.

As shown in FIGS. 1 and 2, a laminated nonwoven fabric 10 of the present invention includes an unfused fiber web (not shown) that includes thermoplastic fibers in a first fiber layer 11 that includes thermoplastic fibers and is formed into an uneven shape. And the fibers of the first fiber layer 11 and the fibers of the second fiber layer 12 obtained from the fiber web are bonded by heating with hot air.
The uneven shape is configured as follows. The sheet-like laminated nonwoven fabric 10 has a convex portion 21 projecting on the first surface side Z <b> 1 on the side viewed from above and a concave portion 22, and a plurality of convex portions 21 are arranged so as to surround the concave portion 22. The portions 21 and the recesses 22 are alternately and continuously arranged in different directions intersecting in plan view of the laminated nonwoven fabric 10. Therefore, similarly to the laminated nonwoven fabric 10, the first fiber layer 11 also has a first convex portion 21A protruding to the first surface side Z1 and a concave first concave portion 22A, and a plurality of the first fibrous layer 11 so as to surround the first concave portion 22A. 21 A of 1st convex parts are distribute | arranged, and 21 A of 1st convex parts and 22 A of 1st recessed parts are alternately and continuously distribute | arranged to each of the different direction which crosses planar view of this 1st fiber layer 11. FIG. Specifically, they are alternately and continuously arranged in the X direction and the Y direction that intersect in plan view.
Further, the first surface side Z1 (hereinafter also referred to as the upper surface side) of the first fiber layer 11 of the laminated nonwoven fabric 10 is opposite to the second surface side Z2 (hereinafter also referred to as the lower surface side). It has the 2nd fiber layer 12 joined along the lower surface side of fiber layer 11. Therefore, the 2nd convex part 21B and the 2nd crevice 22B of the 2nd fiber layer 12 are arranged corresponding to the position where the 1st convex part 21A and the 1st crevice 22A are arranged.

Furthermore the fiber density of the recesses is in the ^{0.01g / cm 3 ~0.08g / cm 3} . The fiber density of the concave portion here refers to the fiber density of the portion of the bottom portion of the concave portion 22 where the first fiber layer 11 and the second fiber layer 12 are combined. If the fiber density of the recess is too low, the shaping of the first fiber layer 11 becomes insufficient, making it difficult to obtain a clear uneven shape. If the fiber density of the recess is too high, the liquid passage time (Liquid passage speed) becomes slow.

  In the present embodiment, the convex portion 21 has a truncated cone shape or a hemispherical shape with a rounded top. Note that the convex portion 21 is not limited to the above shape, and may have any protruding shape. For example, various cone shapes (in this specification, the cone shape means a cone, a truncated cone, a pyramid, a truncated pyramid, an oblique shape, etc. It is practical to include a cone or the like.) In the present embodiment, the convex portion 21 holds a frustoconical or hemispherical inner space having a rounded top portion similar to the outer diameter thereof. The second fiber layer 12 is disposed along the inner space wall.

  The first fiber layer 11 shaped in a concavo-convex shape has a wall portion 23 on the lower side of the top portion (hereinafter also referred to as a convex portion top portion) in the first convex portion 21A. The wall portion 23 forms an annular structure at the convex portion 21. The first recess 22A has a wall 24 on the upper side of the bottom (hereinafter also referred to as a recess bottom). The wall portion 24 forms an annular structure in the recess 22. The wall portion 23 and the wall portion 24 are continuous. The “annular” herein is not particularly limited as long as it has a series of endless shapes in plan view, and may be any shape such as a circle, an ellipse, a rectangle, or a polygon in plan view. In order to maintain the continuous state of the sheet suitably, a circle or an ellipse is preferable. Furthermore, if the "annular" is considered as a three-dimensional shape, a cylindrical shape, a slanted columnar shape, an elliptical columnar shape, a truncated cone shape, a truncated oblique cone shape, a truncated elliptical cone shape, a truncated quadrangular pyramid shape, a truncated oblique pyramid shape Arbitrary ring structures, such as a shape, are mentioned, In order to implement | achieve a continuous sheet | seat state, cylindrical shape, elliptic cylinder shape, truncated cone shape, and truncated elliptical cone shape are preferable.

The above-described laminated nonwoven fabric 10 does not have a bent portion, and is configured by a curved surface that is continuous throughout.
Thus, the laminated nonwoven fabric 10 preferably has a continuous structure in the surface direction. This “continuous” means that there are no intermittent portions or small holes. However, fine holes such as gaps between fibers are not included in the small holes. The small hole can be defined, for example, as a hole having a diameter equivalent to a circle of 1.0 mm or more.

  The fiber material that can be used for the laminated nonwoven fabric 10 of the present invention is not particularly limited. Specific examples include the following fibers. Polyolefin fibers such as polyethylene (PE) fibers and polypropylene (PP) fibers; fibers using a thermoplastic resin such as polyethylene terephthalate (PET) and polyamide alone; composite fibers having a structure such as a core-sheath type and a side-by-side type, such as A core-sheath structure fiber in which the sheath component is polyethylene or low-melting-point polypropylene is preferable, and representative examples of the core / sheath structure fiber include PET (core) and PE (sheath), PP (core) and PE (core). Sheath), fibers of core-sheath structure such as PP (core) and low melting point PP (sheath). More specifically, the constituent fibers preferably include polyolefin fibers such as polyethylene fibers and polypropylene fibers, polyethylene composite fibers, and polypropylene composite fibers. Here, the composite composition of the polyethylene composite fiber is polyethylene terephthalate and polyethylene, and the composite composition of the polypropylene composite fiber is preferably polyethylene terephthalate and low-melting polypropylene, and more specifically, PET (core). And PE (sheath), PET (core), and low melting point PP (sheath). These fibers may be used alone to form a nonwoven fabric, but may be used in combination of two or more.

  The fibers constituting the wall portion 23 have fiber orientation in the direction connecting the convex top portion of the convex portion 21 and the concave bottom portion of the concave portion 22. Therefore, when viewed in a plan view, it has a radial fiber orientation toward the top of the convex part and the bottom of the concave part. Unlike the fiber orientation degree of the first convex portion 21A of the first fiber layer 11 and the fiber orientation degree of the second convex portion 21B of the second fiber layer 12, the fiber orientation degree of the second convex portion 21B is first. It faces in the vertical direction (thickness direction) rather than the fiber orientation degree of the convex portion 21A. When the fiber is oriented in the vertical direction, the effect of receiving the compressive deformation of the first convex portion 21A at high load, preventing crushing, and maintaining the thickness is great. When the fiber orientation is in the horizontal direction, the effect of preventing crushing at high loads is reduced and the thickness is reduced. The fiber orientation degree of the first convex portion 21A is preferably 10 to 30 °, and the fiber orientation degree of the second convex portion 21B is preferably 30 to 60 °.

The laminated nonwoven fabric 10 has a portion 25 having a fiber density lower than that of the first fiber layer 11 and the second fiber layer 12 between the first convex portion 21A and the second convex portion 21B. The presence of the portion 25 having a low fiber density makes it easy for the convex portions 21A of the first fiber layer 11 to be depressed even under a low load, so that the cushioning property of the laminated nonwoven fabric 10 is enhanced.
Further, from the viewpoint of cushioning properties, the density of the first convex portion 21A, the density of the upper portion of the second convex portion 21B, and the density of the lower portion of the second convex portion 21B may have the following relationship. preferable.
It is preferable to have a relationship that the density of the first convex portion 21A> the density of the lower portion of the second convex portion 21B> the density of the upper portion of the second convex portion 21B.
Moreover, it is preferable that the density of 21 A of 1st convex parts is 8-25 mg / cm < ³ >, and it is preferable that the density of the 2nd convex part 21B is 2-8 mg / cm < ³ >. Further, the density of the upper part of the second convex part 21B is preferably 1.5 to 4 mg / cm ³ , and the fiber density of the lower part of the second convex part 21B is preferably 3.5 to 6 mg / cm ³ . Here, the upper part of the 2nd convex part 21B means the 1st fiber layer 11 side when the 2nd fiber layer 12 is divided into 1/2 in the thickness direction. The portion of the second convex portion 21B excluding the upper portion of the second convex portion 21B is referred to as the lower portion.

Next, the dimension specification in the laminated nonwoven fabric 10 of this embodiment is demonstrated below.
Regarding the thickness of the sheet, the total thickness when viewed from the side of the laminated nonwoven fabric 10 is the sheet thickness TS, and the local thickness of the sheet curved in the unevenness is the layer thickness TL. The sheet thickness TS may be adjusted as appropriate depending on the application, but when used as a surface sheet for diapers, sanitary products, etc., 1 mm to 7 mm is preferable, and 1.5 mm to 5 mm is more preferable. By setting it as the range, the body fluid absorption speed at the time of use is high, the liquid return from an absorber is suppressed, and also moderate cushioning property is realizable. The layer thickness TL may be different in each part in the sheet, and may be appropriately adjusted depending on the application. When used as a surface sheet for diapers, sanitary products, etc., the layer thickness TL of the convex top 21T including the first fiber layer 11 and the second fiber layer 12 is 1 mm to 7 mm, preferably 1.5 mm to 5 mm. is there. The layer thickness TL1 of the convex portion top 21TA of the first fiber layer 11 is 0.3 mm to 2.5 mm, preferably 0.6 mm to 1.5 mm. The layer thickness TL2 of the convex top portion 21TB of the second fiber layer 12 is 1 mm to 5 mm, preferably 1.5 mm to 4 mm.
The interval between the convex portions 21 may be appropriately adjusted depending on the application, and when used as a surface sheet such as a diaper or a sanitary product, it is 2 mm to 10 mm, preferably 3 mm to 7 mm. The basis weight of the laminated nonwoven fabric 10 is not particularly limited, but 15~70g / ^{m 2} the average value of the entire sheet, preferably from 20 to 40 g / ^{m 2.}

The laminated nonwoven fabric 10 described in the above embodiment has the following effects.
The laminated nonwoven fabric 10 has excellent liquid permeability even in the recess 22.
Condition layered nonwoven fabric 10 of the present embodiment, since the fiber density of the recessed portion 22 is in the ^{0.01g / cm 3 ~0.08g / cm 3} , the first fibrous layer 11 that is shaped to clear irregular shape Since the fiber density of the concave portion 22 is not too high, the liquid passage time (liquid passage speed) at that portion is increased. Therefore, the laminated nonwoven fabric 10 excellent in liquid permeability can be obtained.

The laminated nonwoven fabric 10 has excellent cushioning properties at low loads.
Since the laminated nonwoven fabric 10 of this embodiment has the part which protruded not only on the single side | surface of a front and back, but both surfaces (both fiber layers), the cushioning characteristic peculiar to the structure is expressed. For example, streak-like projections or single-sided projections will inevitably exhibit elasticity as lines or surfaces. However, according to this embodiment, the two-dimensional movement is well followed and supported by points on both sides. Has a three-dimensional cushioning. In addition, the second fiber layer 12 is disposed along the shape of the irregularities of the first fiber layer 11, and the convex portion 21 (concave portion 22) is crushed in the thickness direction of the laminated nonwoven fabric 10. Has no moderate cushioning. Furthermore, even if the laminated nonwoven fabric 10 is crushed due to the pressing force by the second fiber layer 12, the shape restoring force is large, and the initial cushioning force is easily maintained even if the packing state and wearing are continued. That is, the convex portion 21 and the concave portion 22 are not easily crushed, and are easily recovered even when deformation occurs.
In addition, since the laminated nonwoven fabric 10 includes the portion 25 having a low fiber density, the first convex portion 21A of the first fiber layer 11 is easily recessed even at a low load. If it can be obtained even at low loads, it has an excellent effect.

The laminated nonwoven fabric 10 is obtained by laminating a fiber web on the first fiber layer 11 shaped into a concavo-convex shape, and heat-sealing the fibers of the fiber web to obtain a second fiber layer 12. Since the fiber of the 1st fiber layer 11 and the fiber of the 2nd fiber layer 12 are heat-sealed and joined, it has a clear concavo-convex shape, a low basis weight (30 g / m ² or less), and a thickness of 4.0 mm. It can be set as the above bulky nonwoven fabric.

  Next, an example of a laminated nonwoven fabric production apparatus suitable for producing the laminated nonwoven fabric 10 of the present invention will be described below with reference to FIG. In addition, the manufacturing apparatus of a laminated nonwoven fabric is not limited to the following structures, The manufacturing apparatus of what kind of structure may be sufficient as long as the laminated nonwoven fabric 10 of this invention can be manufactured.

  As shown in FIG. 3, the laminated nonwoven fabric manufacturing apparatus 101 includes a support 110 that transports a first fiber web 13 containing thermoplastic fibers for producing the first fiber layer 11. The first fiber web 13 is supplied to the surface of the support 110, and is subjected to a shaping process for imparting a concavo-convex shape by an air-through method while being placed on the surface of the support 110, and is sent out in a predetermined direction.

  The support 110 is constituted by a conveyor, and the conveyor belt 110B is supported and rotated by rotation support rollers 110R (110Ra, 110Rb, 110Rc, 110Rd) disposed at four positions on the upper and lower ends. It is configured. The rotation support rollers 110R are not limited to four places, and may be arranged so that the conveyor belt 110B rotates smoothly. The conveyor belt 110B has a concavo-convex shape composed of a plurality of protruding portions 110T on its surface, and further has a plurality of ventilation portions (not shown). For example, the protruding portions 110T and the ventilation portions are alternately arranged in the longitudinal and lateral directions of the conveyor belt 110B. The conveyor belt 110B is an endless belt.

  The protruding portion 110T has a shape that tapers toward the tip, and the tip has a rounded shape, for example, one end of a spindle. The height varies depending on the use, standard, etc. of the nonwoven fabric, and is not particularly limited. Usually, it is preferably formed to 2 mm to 10 mm, and the protrusion pitch is 6 mm to 10 mm in the MD direction, and in the CD direction. 4 mm or more and 6 mm or less. The MD is the machine direction and the flow direction of the first fiber web 13 during the production of the nonwoven fabric. The CD is the width direction of the first fiber web 13 and the direction perpendicular to the machine direction. If the height of the protrusion 110T is too low, sufficient unevenness cannot be formed on the first fiber web 13. If the height of the protrusion 110T is too high, the protrusion 110T may be deformed when hot air is blown. 13 may be penetrated. Therefore, the protrusion 110T is appropriately set within the above range. More preferably, it is formed at a height of 3 mm or more and 8 mm or less, is arranged in the MD direction at 6 mm or more and 10 mm or less, and is arranged in the CD direction at 4 mm or more and 6 mm or less.

  The ventilation portion (not shown) includes a plurality of openings arranged on the support 110, and the opening ratio is preferably set to 20% or more and 45% or less with respect to the surface area of the support 110. If the aperture ratio is too low, it will be difficult to form a sufficient uneven shape on the first fiber web 13. If the aperture ratio is too high, the first fiber web 13 will move below the support 110 when hot air is blown. Then, it becomes difficult to peel from the support 110, and there is a possibility that the shaped shape is deteriorated and fluff is likely to be formed. Therefore, the aperture ratio is set. The aperture ratio is more preferably 25% or more and 40% or less, and particularly preferably 30% or more and 35% or less.

  The support 110 is supported by the rotation of the conveyor belt 110B by the rotation support roller 110R, so that the first fiber web 13 is hooked by the protrusion 110T on the surface side having the protrusion 110T. The fiber web 13 is conveyed. Above the protrusion 110T of the support 110, a first nozzle 111 that performs the first air-through process by blowing the first hot air W1 in order along the supply direction of the first fiber web 13; The second nozzle 112 that blows the second hot air W2 to perform the second air through process and the third nozzle 113 that blows the third hot air W3 to perform the third air through process are arranged. A cooling unit (not shown) for cooling the first fiber web 13 may be disposed between the first nozzle 13 and the third nozzle 113. The first and second nozzles 111 and 112 perform upstream air-through, and the third nozzle 113 performs downstream air-through.

  The first nozzle 111 includes a first heater (not shown), and the first hot air W1 heated by the first heater is applied to the surface of the first fiber web 13 conveyed by the support 110, for example. Spray almost vertically. The blowout hole of the first nozzle 111 preferably has a length in the MD direction of 1 mm or more and 20 mm or less, and a length in the CD direction is a web width or more, or a width for performing a shaping process. The blow-out holes have a single or multi-row slit shape, and a form in which round holes, long holes, or square holes are arranged in a staggered manner or in parallel in a single row or multiple rows. More preferably, it has a slit shape in a row of 2 mm or more and 20 mm or less. Thus, since the blowing holes of the first nozzle 111 are arranged, the first hot air W1 is blown at a uniform wind speed in the width direction of the surface of the first fiber web 13. As the first hot air W1, air, nitrogen or water vapor heated to a predetermined temperature by the first heater can be used. Preferably, air with low cost is used.

  The first hot air W1 blown out from the first nozzle 11 is controlled by the first heater to a temperature at which the fibers of the first fiber web 13 are fused to maintain a concavo-convex shape. For example, when the fibers of the first fiber web 13 are composite fibers having a core-sheath structure in which the core part is polyethylene terephthalate (PET) and the sheath part is polyethylene (PE), the temperature of the first hot air W1 is preferably It is controlled to 80 ° C. or more and 155 ° C. or less. The first hot air W1 is preferably controlled to a wind speed of 20 m / sec or more and 120 m / sec or less. Furthermore, the spraying time of the first hot air W1 is preferably controlled to be 0.01 seconds or more and 0.5 seconds or less.

  The second nozzle 112 blows the second hot air W2 heated by a second heater (not shown), for example, substantially perpendicularly onto the surface of the first fiber web 13 conveyed by the conveyor belt 110B. It is desirable to use a punching metal that is regularly opened in the width direction and the flow direction for the blowing holes of the second nozzle 112. The hole area ratio is preferably 10% or more and 40% or less, and punching metals may be combined in multiple stages. Thus, since the blowing hole of the second nozzle 112 is formed, the second hot air W2 is blown at a uniform temperature and wind speed in the width direction of the surface of the first fiber web 13. As the second hot air W2, air, nitrogen or water vapor heated by the second heater can be used. Preferably, air with low cost is used.

The second hot air W2 blown out from the second nozzle 112 is formed between the fibers of the first fiber web 13 while maintaining the irregular shape of the first fiber web 13 shaped by a second heater (not shown). The temperature is controlled so as to fuse. For example, when the fiber of the first fiber web 13 is a composite fiber having a low melting point component and a high melting point component having a higher melting point than the low melting point component, the second hot air W1 is equal to or higher than the melting point of the low melting point component. The temperature is controlled below the melting point of the high melting point component of the fibers of the web 13. For example, when the fiber of the first fiber web 13 is a composite fiber having a core-sheath structure in which the core part is PET and the sheath part is PE as described above, the second hot air W1 is a temperature of 130 ° C. or higher and 155 ° C. or lower. It is controlled by hot air. The second hot air W2 is controlled to a wind speed of 1 m / sec or more and 10 m / sec or less. Further, the blowing time of the second hot air W2 is controlled to be 0.03 seconds or more and 5 seconds or less.
In this way, the first fiber web 13 is shaped and fused to obtain the first fiber layer 11.

  The cooling unit (not shown) is a space arranged between the second nozzle 112 that performs the second air-through process and the third nozzle 113 that performs the third air-through process. By arranging this space, in other words, by not performing the second air-through process and the third air-through process continuously, the melting point of the fibers of the first fiber layer 11 after the second air-through process. Cool naturally to a lower temperature. Alternatively, as will be described later, the cooling unit can use means for forcibly cooling the first fiber layer 11.

  The second fiber web 14 is supplied from the upper surface side to the first fiber layer 11, and the second fiber web 14 is superimposed on the first fiber layer 11 by the guide roller 121. The third nozzle 113 is a conveyor belt (not shown) in a state in which the third hot air W3 heated by a third heater (not shown) is overlapped with the second fiber web 14 on the first fiber layer 11. ), For example, is blown out substantially perpendicular to the overlapped fiber web. It is desirable to use a punching metal that is regularly opened in the width direction and the flow direction for the blowing holes of the third nozzle 113. The hole area ratio is preferably 10% or more and 40% or less, and a multi-stage punching metal may be combined. Thus, since the blowing holes of the third nozzle 113 are arranged, the third hot air W3 is blown at a uniform temperature in the width direction of the surface of the second fiber web 14. The third hot air W3 can be air, nitrogen, or water vapor heated by the third heater. Preferably, air with low cost is used. In addition, the said conveyor belt which has the air permeability which supports the 1st fiber layer 11 and the 2nd fiber web 14 which were piled up is distribute | arranged to the downstream of the 3rd hot air W3.

  The third hot air W3 blown out from the third nozzle 113 is in a state where the second fiber web 14 is superposed on the first fiber layer 11 by a third heater (not shown) and the first fiber layer 11. The first fiber layer 11 and the second fiber web 14 are controlled to a temperature at which the first and second fiber webs 14 are fused in a state where the uneven shape is maintained. For example, when the fiber of the second fiber web 14 is a composite fiber having a core-sheath structure in which the core portion is PET and the sheath portion is PE as described above, the third hot air W3 has a temperature of 130 ° C. or higher and 155 ° C. or lower. It is controlled by hot air. The third hot air W3 is controlled to a wind speed of 0.4 m / sec or more and 5 m / sec or less. Further, the blowing time of the third hot air W3 is controlled to be not shorter than 2 seconds and not longer than 20 seconds.

  In the blowing direction of the first nozzle 111, a duct 115 is arranged for exhausting the first hot air W <b> 1 blown out from the first nozzle 111 and passed through the first fiber web 13 and the support 10. The duct 115 may be connected to an exhaust device (not shown) that discharges the sucked first hot air W1. Further, in the blowing direction of the second nozzle 112, a duct 116 is arranged for exhausting the second hot air W2 blown from the second nozzle 112 and passed through the first fiber web 13 and the support 110. The duct 116 may be connected to an exhaust device (not shown) that discharges the sucked second hot air W2. Further, in the blowing direction of the third nozzle 113, a duct 17 is arranged for exhausting the third hot air W <b> 3 blown out from the third nozzle 113 and passed through the second fiber web 14 and the first fiber layer 11. An exhaust device (not shown) that discharges the sucked third hot air W3 may be connected to the duct 17. Each of the exhaust devices may be connected to the ducts 115, 116, 117 as one exhaust device.

Next, another apparatus for producing a laminated nonwoven fabric suitable for producing the laminated nonwoven fabric 10 according to the present invention will be described below with reference to FIG.
As shown in FIG. 4, the laminated nonwoven fabric manufacturing apparatus 102 supplies the second fiber web 14 from the lower surface side of the first fiber layer 11 in the above-described laminated nonwoven fabric manufacturing apparatus 101, and is guided by the guide roll 122. The second fiber web 14 is superposed under the one fiber layer 11. In the third air-through process, the third hot air W3 is blown from the first fiber layer 11 side. Therefore, except the supply part of the said 2nd fiber web 14, it has the same structure by the component similar to the manufacturing apparatus 101 of the said laminated nonwoven fabric.

  Next, an embodiment of a method for producing a laminated nonwoven fabric according to the present invention will be described below with reference to FIG. This laminated nonwoven fabric manufacturing method is realized, for example, by the laminated nonwoven fabric manufacturing apparatus 101 or 102 described above. Hereinafter, the manufacturing method by the manufacturing apparatus 101 of a laminated nonwoven fabric is demonstrated.

As shown in FIG. 3 described above, the first fiber web 13 made to a predetermined thickness by a card machine (not shown) is supplied to the upper surface side of the support 110 where the protruding portions 110T are arranged.
The fiber material that can be used for the fibers of the first fiber web 13 is not particularly limited. Specific examples include the following fibers. There are polyolefin fibers such as polyethylene (PE) fibers and polypropylene (PP) fibers; fibers using a thermoplastic resin such as polyethylene terephthalate (PET) and polyamide alone. In addition, there are composite fibers having a structure such as a core-sheath type and a side-by-side type. In the present invention, it is preferable to use a composite fiber. Examples of the composite fiber include a core-sheath fiber having a high melting point component as a core portion and a low melting point component as a sheath portion, and a side-by-side fiber in which a high melting point component and a low melting point component are arranged in parallel. Preferable examples thereof include core-sheath fibers in which the sheath component is polyethylene or low-melting polypropylene, and typical examples of the core / sheath fibers include PET (core) / PE (sheath), PP (core ) / PE (sheath), PP (core) / low melting point PP (sheath) and the like. More specifically, the constituent fibers preferably include polyolefin fibers such as polyethylene fibers and polypropylene fibers, polyethylene composite fibers, and polypropylene composite fibers. Here, the composite composition of the polyethylene composite fiber is polyethylene terephthalate / polyethylene, and the composite composition of the polypropylene composite fiber is preferably polyethylene terephthalate / low melting point polypropylene, and more specifically, PET (core). / PE (sheath), PET (core) / low melting point PP (sheath). These fibers may be used alone to form a nonwoven fabric, but can also be used as a mixed fiber in which two or more kinds are combined.

Then, a first nozzle is applied to the first fiber web 13 fed to the surface of the support 110 as a previous air-through process in which hot air is blown onto the first fiber web 13 to follow the uneven shape of the breathable support 110. The 1st air through process which blows the 1st hot air W1 from 111 is performed. At this time, the first hot air W1 is blown from the vertical direction on the surface of the first fiber web 13 mounted on the support 110. Further, the number of blowouts of the first nozzle 111 may be a plurality of locations along the conveying direction of the first fiber web 13. By the first hot air W1, the first fiber web 13 is shaped into a concavo-convex shape along the shape of the protruding portion 110T of the support 110. The fusion of the fibers of the first fiber web 13 may be such that the uneven shape can be maintained. At this time, the temperature of the first hot air W1 varies depending on the type of fiber, the processing speed, the wind speed of the hot air, and the like, but is not uniquely determined. However, the fiber of the first fiber web 13 has a polyethylene terephthalate (core portion). PET) and the sheath part is a composite fiber having a core-sheath structure of polyethylene (PE), preferably 80 ° C. or higher and 155 ° C. or lower, more preferably 130 ° C. or higher and 135 ° C. or lower.
In addition, when the temperature of the 1st hot air W1 is too low, the return of a fiber will arise and a shaping property will fall. On the other hand, when the temperature is too high, the fibers are fused at a stretch, and the formability is impaired due to a decrease in the degree of freedom.

  The first hot air W1 is preferably set to a wind speed of 20 m / sec or more and 120 m / sec or less. When the wind speed of the 1st hot air W1 is too slow, sufficient shaping cannot be performed and shaping property may be impaired. On the other hand, if the wind speed is too high, the fibers of the first fiber web 13 are selected by the protrusions 110T and become too shaped. Therefore, the wind speed of the 1st hot air W1 shall be said range, More preferably, you may be 40 m / sec or more and 80 m / sec or less.

Furthermore, the blowing time of the first hot air W1 is preferably 0.01 seconds to 0.5 seconds, and more preferably 0.04 seconds to 0.08 seconds. If the spraying time is too short, the fibers of the first fiber web 13 are not sufficiently fused with each other, and the uneven shape cannot be sufficiently shaped. On the other hand, if the spraying time is too long, the fusion of the fibers of the first fiber web 13 proceeds too much, and the formability is impaired due to a decrease in the degree of freedom.
And the 1st hot air W1 which passed the 1st fiber web 13 is discharged | emitted outside from the duct 115 through the ventilation part of the support body 110. FIG.

  Next, the 1st fiber web 13 is conveyed to the spray position of the 2nd hot air W2 of the 2nd nozzle 112 with rotation of the conveyor belt 110B of the support body 110. FIG. Further, as a previous air-through process, the second hot air W2 is blown to the first fiber web 13 by the second nozzle 112, and the fibers are fused while maintaining the uneven shape of the first fiber web 13, thereby forming the uneven shape. A second air-through step for fixing is performed. At this time, the second hot air W <b> 2 is blown from the direction perpendicular to the surface of the first fiber web 13. The number of blowouts of the second nozzle 112 is preferably set at a plurality of locations along the conveying direction of the first fiber web 13.

The temperature of the second hot air W2 varies depending on the type of fiber, the processing speed, the wind speed of the hot air, etc., but is not uniquely determined. However, the fibers of the first fiber web 13 are the core of PET and PE as described above. In the case of a composite fiber having a sheath structure, it is set to be equal to or higher than the melting point of the low melting point component of the fiber of the first fiber web 13 and lower than the melting point of the high melting point component of the fiber of the first fiber web 13. It is set to 130 ° C. or higher and 155 ° C. or lower, preferably 135 ° C. or higher and 150 ° C. or lower.
Note that when the temperature of the second hot air W2 is lower than the melting point of the low melting point component of the fibers of the first fiber web 13, the retention of the uneven shape is lowered, and the melting point of the high melting point component of the fibers of the first fiber web 13 is exceeded. When it becomes, a texture will worsen and it will become difficult to become bulky.

  The second hot air W2 is preferably set slower than the wind speed of the first hot air W1, and is set to 1 m / sec or more and 10 m / sec or less. If the wind speed of the second hot air W2 is too slow, the amount of heat is insufficient, and the nonwoven fabric strength is insufficient. On the other hand, if the wind speed is too high, the thickness of the first fiber web 13 is reduced by the wind pressure, and when heated in this state, the fibers are fused to each other, so that the touch becomes hard, the thickness is reduced, and the liquid permeability is reduced. It becomes insufficient. Therefore, the wind speed of the 2nd hot air W2 shall be said range, Preferably it shall be 2 m / sec or more and 8 m / sec or less.

Furthermore, the spray time of the second hot air W2 is set to 0.03 seconds to 5 seconds, preferably 0.1 seconds to 1 second. If the spraying time is too short, the fibers of the first fiber web 13 cannot be sufficiently fused together, and it becomes difficult to fix the uneven shape. On the other hand, if the spraying time is too long, the fibers of the first fiber web 13 are excessively fused with each other, making it difficult to obtain liquid permeability.
As described above, the first fiber layer 11 formed with the first fiber web 13 in the first and second air-through processes is obtained.

Next, the first fiber layer 11 shaped in the first and second air-through processes is cooled. This cooling can be performed by natural cooling or forced cooling. The cooling temperature is lower than the melting point of the thermoplastic fiber of the first fiber layer 11, preferably lower than the melting point of the low melting point component of the fibers constituting the first fiber layer 11. Preferably, the temperature is set to 100 ° C. or lower.
By this cooling, the fusion point between the fibers of the first fiber layer 11 is firmly solidified. In particular, by cooling the first fiber layer 11 to 100 ° C. or lower, the intersection part of the fusion of the fibers can be more firmly fixed, and the thickness of the first fiber layer 11 can be maintained. When the sheath resin is PE, the melting point is 125 ° C. to 135 ° C., but the softening point temperature is 100 ° C. to 130 ° C., so that the solidification is further ensured by cooling to 100 ° C. or lower.

And the shaped 1st fiber layer 11 is conveyed to the spray position of the 3rd hot air W3 of the 3rd nozzle 113. FIG. In the meantime, the second fiber web 14 is supplied from the upper surface side to the cooled first fiber layer 11, and the second fiber web 14 is superimposed on the first fiber layer 11 by the guide roller 121. And a 3rd air through process is performed. In this third air-through process, the third hot air W3 is blown from the second fiber web 14 side, and the fibers of the second fiber web 14 are heat-sealed in a state where the uneven shape of the first fiber layer 11 is maintained. Thus, at the same time as obtaining the second fiber layer 12, the fibers of the first fiber layer 11 and the second fiber web 14 are bonded by heat fusion. The temperature of the third hot air W3 at this time is not uniquely determined because it varies depending on the type of fiber, the processing speed, the wind speed of the hot air, etc., but the fibers of the second fiber web 14 are made of PET as described above. In the case of a composite fiber having a core-sheath structure with PE, the temperature is 130 ° C. or higher and 155 ° C. or lower, preferably 130 ° C. or higher and 145 ° C. or lower.
If the temperature of the third hot air W3 is too low, the fibers cannot be fused together, and it becomes difficult to join the first fiber layer 11 and the second fiber web 14 together. On the other hand, if the temperature of the third hot air W3 is too high, the fibers are too fused with each other, making it difficult to obtain liquid permeability.

  The third hot air W3 is controlled to a wind speed of 0.4 m / sec or more and 5 m / sec or less, preferably 1 m / sec or more and 3 m / sec or less. If the wind speed is too slow, the amount of heat is insufficient, so that the nonwoven fabric strength of the second fiber layer 12 (second fiber web 14) becomes insufficient. On the other hand, if the wind speed is too high, the thickness of the second fiber web 14 is reduced by the wind pressure, and if heated in that state, the fibers are fused more frequently, so that the touch becomes harder, the thickness becomes thinner, and the liquid permeability becomes lower. It becomes insufficient.

  Further, the blowing time of the third hot air W3 is controlled to be 1 second to 20 seconds, preferably 2 seconds to 15 seconds. If the spraying time is too short, the fibers of the second fiber web 14 cannot be fused together, and the fibers of the first fiber layer 11 and the second fiber web 14 cannot be sufficiently fused. On the other hand, if the spraying time is too long, the fibers of the second fiber web 14 and the fibers of the first fiber layer 11 and the second fiber web 14 are fused too much, and it becomes difficult to obtain liquid permeability.

  Therefore, in the third air-through step, the uneven shape of the first fiber layer 11 becomes a support when shaping the second fiber web 14, and the second fiber web 14 is removed from the first fiber without impairing the liquid permeability. The fibers of the first fiber layer 11 and the fibers of the second fiber web 14 can be joined together along the irregular shape formed of the fiber layer 11. Further, by adjusting the wind speed of the third hot air W3 at the bottom of the portion that becomes the concave portion of the first fiber layer 11 when viewed from the second fiber web 14 side, the fiber entry of the second fiber web 14 is reduced. it can. Thus, in the state of the laminated nonwoven fabric 10, a portion 25 having a low fiber density is produced between the convex portion 21A of the first fiber layer 11 and the convex portion 21B of the second fiber layer 12 (second fiber web 14). be able to. The portion 25 having a low fiber density is a portion where the fiber density at the top of the convex portion of the second fiber layer 12 is substantially low.

  In the method for producing a laminated nonwoven fabric according to the first embodiment described above, the laminated nonwoven fabric with a low weight per unit having a clear uneven shape, little fluff coming off due to wear, high bulk at low load, and excellent liquid permeability in the recess. Can provide.

That is, the first hot air W1 blown out from the first nozzle 111 can keep the fibers of the first fiber web 13 in an uneven shape. For this reason, the fibers of the first fiber web 13 that are trapped between the protrusions 110T of the support 110 are difficult to return. In this state, the fibers of the first fiber web 13 are fused together by the second hot air W2 blown from the second nozzle 112, and can be fixed in a state where the uneven shape is maintained. Thus, since the first and second hot air W1 and W2 are blown onto the first fiber web 13, the fibers of the first fiber web 13 are softened by heat, and the surface of the protrusion 110T of the support 110 is softened. It becomes easy to follow the shape, and the retention of the uneven shape is improved. In that case, since the 1st, 2nd hot air W1, W2 passes the ventilation hole distribute | arranged to the support body 110, it becomes easy to make the 1st fiber web 13 follow the surface of the protrusion-shaped part 110T. As a result, it is possible to obtain the first fiber layer 11 which is a shaped nonwoven fabric having a low basis weight (for example, 30 g / cm ² or less) and high bulk (for example, 4.0 mm or more at a low load) with good shapeability.
Further, the second fiber web 14 is superimposed on the first fiber layer 11, and the second fiber web 14 (second fiber layer 12) is bonded to the first fiber layer 11 by fusion-bonding the fibers with the third hot air W3. Therefore, even if it is the recessed part 22 of the laminated nonwoven fabric 10, a fiber density does not become high and it becomes the thing excellent in liquid permeability with a short liquid passage time (liquid passage speed is quick). Furthermore, since the 3rd hot air W3 is blown from the 2nd fiber web 14 side, since the 1st fiber layer 11 side shaped in the uneven | corrugated shape becomes a downstream of the 3rd hot air W3, the unevenness | corrugation of the 1st fiber layer 11 The shape is reliably maintained, and the fibers of the second fiber web 14 can easily come into contact with the fibers of the first fiber layer 11, so that the fusion bonding between the second fiber web 14 and the first fiber layer 11 is ensured. it can. Furthermore, a portion 25 having a low fiber density can be produced between the first convex portion 21A of the first fiber layer 11 and the second convex portion 21B of the second fiber layer 12 (second fiber web 14). Further, the cushioning property at a low load is further improved.
In addition, since the second fiber layer 12 has a high degree of orientation in the vertical direction, the second fiber layer 12 has a function of suppressing crushing when a load is applied to the laminated nonwoven fabric 10.
By using the laminated nonwoven fabric 10 of the present invention, it has a clear concavo-convex shape, has little fluff due to wear, is bulky at low load, has little fluff due to wear, and has excellent liquid permeability in the recess. An absorbent article having a basis weight can be obtained.

Next, another preferred embodiment (second embodiment) of the method for producing a laminated nonwoven fabric according to the present invention will be described below with reference to FIG.
As shown in FIG. 4, the laminated nonwoven fabric manufacturing method according to the second embodiment is realized by the laminated nonwoven fabric manufacturing apparatus 102 described above.

  In the same manner as in the manufacturing method of the first embodiment, the first fiber layer 11 is formed and conveyed to the position where the third hot air W3 is sprayed from the third nozzle 113. During this period, it is preferable to cool the first fiber layer 11 as in the manufacturing method of the first embodiment.

The second fiber web 14 is supplied from the lower surface side to the cooled first fiber layer 11, and the second fiber web 14 is overlaid under the first fiber layer 11. And a 3rd air through process is performed. In this third air-through process, the third hot air W3 is blown from the first fiber layer 11 side, and the fibers of the second fiber web 14 are heat-sealed with each other while the uneven shape of the first fiber layer 11 is maintained. Thus, at the same time as obtaining the second fiber layer 12, the fibers of the first fiber layer 11 and the second fiber web 14 are bonded by heat fusion. The temperature of the third hot air W3 at this time is not uniquely determined because it varies depending on the type of fiber, the processing speed, the wind speed of the hot air, etc., but the fibers of the second fiber web 14 are made of PET as described above. In the case of a composite fiber having a core-sheath structure with PE, it is preferably 130 ° C. or higher and 155 ° C. or lower, more preferably 130 ° C. or higher and 145 ° C. or lower.
If the temperature of the third hot air W3 is too low, the fibers cannot be fused together, and it becomes difficult to join the first fiber layer 11 and the second fiber web 14 together. On the other hand, if the temperature of the third hot air W3 is too high, the fibers are too fused with each other, making it difficult to obtain liquid permeability.

  The third hot air W3 is preferably controlled to a wind speed of 0.4 m / sec or more and 5 m / sec or less, more preferably 1 m / sec or more and 3 m / sec or less. If the wind speed is too slow, the amount of heat is insufficient, so that the nonwoven fabric strength of the second fiber layer 12 (second fiber web 14) becomes insufficient. On the other hand, if the wind speed is too high, the thickness of the second fiber web 14 is reduced by the wind pressure, and if heated in that state, the fibers are fused more frequently, so that the touch becomes harder, the thickness becomes thinner, and the liquid permeability becomes lower. It becomes insufficient.

  Moreover, the blowing time of the third hot air W3 is preferably controlled to be 1 second or longer and 20 seconds or shorter, more preferably 2 seconds or longer and 15 seconds or shorter. If the spraying time is too short, the first fiber layer 11 and the fiber second fiber web 14 cannot be sufficiently fused. On the other hand, if the spraying time is too long, the fibers of the first fiber layer 11 and the second fiber web 14 are excessively fused, the thickness is reduced, and it is difficult to obtain cushioning properties and liquid permeability.

  In the third air through step, the second fiber web 14 is shaped so as to follow the uneven shape of the first fiber layer 11. Further, by controlling the wind speed of the third hot air W3, it is possible to create a low fiber density portion 25 between the first fiber layer 11 and the second fiber layer 12 in the convex portion 21 of the laminated nonwoven fabric 10, A space can also be created by reducing the wind speed of the third hot air W3. Due to this space, the top of the convex portion of the first fiber layer 11 is only one layer of the first fiber layer 11, so the elasticity at that portion is weak, and the cushion at a lower load than the manufacturing method of the first embodiment. Can be further improved. In addition, even if it says that elasticity becomes weak, it is not the weakness which cannot be restored | restored because the convex part 21 is crushed.

  In 2nd Embodiment of the manufacturing method of the above-mentioned laminated nonwoven fabric, the effect similar to 1st Embodiment of the manufacturing method of the above-mentioned laminated nonwoven fabric is obtained.

Hereinafter, the present invention will be described in more detail with reference to examples in which a shaped nonwoven fabric was produced by the method for producing a shaped nonwoven fabric according to the first and second embodiments described above and comparative examples. The present invention is not limited to these examples.
[Example 1-4]
The laminated nonwoven fabric 10 of Example 1 uses a card web for the first fiber web 13 for producing the first fiber layer 11, and also uses a card web for the second fiber web 14 for producing the second fiber layer 12. It manufactured on condition of the following by the 1st manufacturing method. That is, a composite fiber having a core-sheath structure in which the core part is polyethylene terephthalate (melting point: 258 ° C.) and the sheath part is polyethylene (melting point: 130 ° C.) is used for the fiber of the first fiber web 13. The mixing ratio was 100%, and the fineness was 2.9 dtex. The 1st fiber web 13 was conveyed by the support body 110, and the 1st hot air W1 and the 2nd hot air W2 were sprayed on the surface of the support body 110, and it was formed in the uneven | corrugated shape. Thereafter, the first fiber web 13 is naturally cooled, the second fiber web 14 is superimposed on the upper surface side, and then the third hot air W3 is blown to the second fiber web 14 on the first fiber layer 11. A test body of the laminated nonwoven fabric 54 to which the fiber layer 12 was bonded was manufactured. The first hot air W1 had a temperature of 130 ° C., a wind speed of 40 m / sec, and a blowing time of 0.06 seconds. The second hot air W2 had a temperature of 150 ° C., a wind speed of 4.0 m / sec, and a blowing time of 0.7 seconds. Further, the third hot air W3 had a temperature of 139 ° C., a wind speed of 1.5 m / sec, and a blowing time of 13 seconds.
Example 2 was the same as Example 1 except that the lamination fusion condition was the second production method.
Example 3 was the same as Example 1 except that the temperature of the lamination fusion condition was high and the wind speed was high. In this case, the temperature of the third hot air W3 was set to 147 ° C., the wind speed was set to 2 m / sec, and the blowing time was set to 13 seconds.
Example 4 was the same as Example 1 except that the heating time for the lamination fusion condition was shortened. The heating time in this case was set to 4 seconds.

[Comparative Example 1-3]
Comparative Example 1 was the same as Example 1 except that the first fiber layer was not shaped and was in an unfused web when joined to the second fiber layer.
Comparative Example 2 was the same as Comparative Example 1 except that the first fiber layer and the second fiber layer were air-through nonwoven fabrics. In this case, the hot air processed into the air-through nonwoven fabric had a temperature of 139 °, a wind speed of 1.5 m / sec, and a blowing time of 13 seconds.
Comparative Example 3 was the same as Comparative Example 2 except that the bonding condition between the first fiber layer and the second fiber layer was embossing by heating and pressing. In this case, the heating temperature was set to 125 ° C., and the pressure linear pressure was set to 60 kg / cm.

Next, the measurement method will be described.
The temperature of the first hot air W1 is measured by an anemone master (trade name) manufactured by Nippon Kanomax Co., Ltd., just below the outlet of the first nozzle 111, and the wind speed is the total pressure immediately below the outlet of the first nozzle 11 by a Pitot tube. The static pressure was pulled from the dynamic pressure, and the flow rate was calculated from a Pitot tube. The temperature and wind speed of the second hot air W2 were determined by measuring directly under the outlet of the second nozzle 112 by the anemo master. The temperature and wind speed of the third hot air W3 were determined by the anemo master.

  The method for measuring the thickness of the nonwoven fabric was measured using a thickness measuring instrument in a state where a load of 49 Pa was applied to the nonwoven fabric and a load of 4.9 kPa was applied. A thickness meter (for example, trade name: ABSOLUTE) manufactured by MITUTOYO was used as the thickness measuring instrument. The thickness was measured at 10 points, and the average value was calculated as the thickness.

The fiber density (g / cm ³ ) of the first fiber layer 11, the second fiber layer 12, and the recesses was determined by the formula [weight per unit area (g / m ² )] / [thickness (mm)] × 1000. 1000 is a coefficient for matching the units of the left side and the right side.
Regarding the thickness (TL1) of the first fiber layer 11 and the thickness (TL2) of the second fiber layer 12, the thickness of the recess 22 was obtained by the following method. The laminated nonwoven fabric 10 was cut in the thickness of the laminated nonwoven fabric 10 with the apex of the convex portion 21 in the CD direction. The cut laminated nonwoven fabric 10 was placed on a black table, and a cross section in the CD direction was photographed with a microscope VHX-900 (manufactured by Keyence Corporation) with a load of 49 Pa applied, and a 30-100 times magnified photograph. Got. Each of the 1st fiber layer 11 and the 2nd fiber layer 12 which intersects the perpendicular which passes the width direction center of convex part 21 of the 1st fiber layer 11 of this enlarged photograph in the thickness direction, and the perpendicular line which passes the width direction center of concave part 22 It was determined by measuring the distance of the intersection of the top and bottom fibers of the layer. The thickness of the recess 22 is defined as the distance between the intersection of the upper fiber and the perpendicular of the first fiber layer 11 and the intersection of the lower fiber and the perpendicular of the second fiber layer 12 at the bottom of the recess 22.

Moreover, the fiber density of the convex part 21 upper part side and the convex part 21 lower part side of the 2nd fiber layer 12 was calculated | required with the following method.
The laminated nonwoven fabric 10 is cut in the CD direction with the apex of the protrusion 21 in the CD direction, the laminated nonwoven fabric 10 is cut, the laminated nonwoven fabric 10 is placed on a black base, and a cross section in the CD direction is applied to the microscope VHX-900 under a load of 49 Pa. An enlarged photograph of 30 to 100 times was obtained using (manufactured by Keyence Corporation). For the data (jpeg) of this enlarged photograph, the thickness TL2 of the second fiber layer 12 is equally divided (convex portion upper side and convexity using image analysis software (Nexus New Nexus Qube (trade name)). The binarization process was performed on the range surrounded by the CD direction length of 0.3 to 0.6 mm, and the area ratio of the fibers occupying the space on the convex upper part side and the convex lower part side was determined. . Each area ratio is defined as a fiber amount d1 on the convex portion upper side and a fiber amount d2 on the convex portion lower side, and α calculated by the fiber amount ratio α = d2 / d1 is a fiber amount ratio between the upper and lower portions of the second convex portion 21A. It was. This was performed for 10 places, and an average value was obtained. If this fiber amount ratio is larger than 1, it indicates that the amount of fiber at the top of the convex portion is small and the amount of fiber at the bottom of the convex portion is large. Using this α, the fiber density of the convex upper part side and the convex lower part side was obtained by the following calculation.
Fiber density on the upper side of the convex portion = second fiber layer basis weight × α / ((α + 1) × (TL2 / 2))
Fiber density on the lower side of the convex portion = second fiber layer basis weight × 1 / ((α + 1) × (TL2 / 2))

The fiber orientation degree of the convex part 21 was calculated | required as follows.
As shown in FIG. 5, a cross section of the laminated nonwoven fabric 10 was photographed with a microscope VHX-900 (manufactured by Keyence Corporation) at a magnification of 30 to 100 times with a load of 49 Pa applied. The predetermined position of the cross section of the photographed laminated nonwoven fabric 10 is partitioned by a predetermined range A, 20 fibers 15 within the partitioned range are selected, and the boundary of the above range for each of the selected fibers 15 A line connecting the intersection points with the measurement line 16 was taken as a measurement line 16. For convenience, six fibers 15 are drawn in the drawing. The predetermined position is a position at which the degree of orientation is to be examined, and is, for example, a central portion in the thickness direction at the center of the convex portions of the first fiber layer 11 and the second fiber layer 12. The predetermined range A is, for example, a circle having a diameter of 0.5 mm. In addition, a line parallel to the sheet surface of the laminated nonwoven fabric 10 in the cross section was defined as a reference line 17. When the measurement line 16 and the reference line 17 did not intersect, the measurement line 16 was extended in a straight line to a position where it intersected with the reference line 17. Each angle at the intersection of the 20 measurement lines 16 and the reference line 17 was measured, and the average value was calculated as the orientation degree. In the drawing, for the sake of easy understanding, a schematic diagram is shown instead of a photograph.

Next, the evaluation method will be described. Evaluation examined the performance of the nonwoven fabric as sheet performance.
Sheet performance evaluated the "cushioning property", "liquid passage time", etc. of the laminated nonwoven fabric.

The “cushion property” was evaluated by the linearity (LC value) of the compression characteristics with a texture measuring device (KES).
When the WC value is less than 0.85, the cushioning property is good.
When the WC value is 0.85 or more and less than 0.7, the cushioning property is slightly inferior, and Δ mark,
When the WC value is 0.7 or more, the cushioning property is inferior, and is indicated by x.

“Liquid transit time” was operated according to a liquid strike-through time method according to EDANA-150.5-02 (European Disposables And Nonwovens Association). The strike-through value used in the present invention is the time (unit: seconds) for 10 g of the test solution to pass through the nonwoven fabric that is a test specimen for measurement, and the smaller the strike-through value, the faster the test solution passes through the nonwoven fabric. Means. For the measurement of the strike-through value, using a testing machine LISTER manufactured by Lenzing Technik, the measuring unit of this testing machine was placed on a non-woven fabric, and EDANA-150.5-02 liquid defined by this testing machine. The testing machine was operated according to the strike through time method. Under the non-woven fabric, 20 sheets of filter paper (STRIKE-THROUGH filter paper LTD STRIKE-THROUGH (trade name) manufactured by HOLLINGSWORTH & VOSE COMPANY LTD) were placed to replace the absorbent. As the test solution, a solution prepared as described below was used.
Into a 2 L beaker, 1500 g of ion-exchanged water was added, and 5.3 g of sodium carboxymethylcellulose [KMC-Na, manufactured by Kanto Chemical Co., Ltd.] was added while stirring with a magnetic stirrer (this solution is referred to as “A”). Next, 556 g of ion-exchanged water is put into a 1 L beaker, and 27.0 g of sodium chloride (manufactured by Kanto Chemical Co., Inc.) and 12 g of sodium hydrogen carbonate (NaHCO ₃ , manufactured by Kanto Chemical Co., Ltd.) are added while stirring with a stirrer. (This solution is referred to as “B”). Furthermore, 900 g of glycerin was weighed out into a 3 L beaker, and the above (A) and (B) were added and stirred. Furthermore, 15 ml of an aqueous solution of a nonionic surfactant “Emulgen 935” [manufactured and sold by Kao Co., Ltd.] (surfactant / water) = 1 g / L, and food red No. 2 [released by Eisen Co., Ltd., Hodogaya Chemical Co., Ltd., manufacturer: Daiwa Kasei Co., Ltd.] 0.3 g was added and stirred. The solution thus obtained was subjected to suction filtration using a glass filter, and the filtrate was used as simulated blood. In the preparation of simulated blood, other nonionic surfactants can be used in place of the above-described surfactants, and the same results can be obtained.
And, when the liquid passage time is less than 4 seconds, it is marked as ◯, when the liquid passage time is 4 seconds or more and less than 6 seconds, it is △, and when the liquid passage time is 6 seconds or more, it is very slow. Expressed with a mark.

  Table 1 shows the results of the physical properties (overall weight, low load thickness, high load thickness, concave fiber density, convex fiber orientation) and performance (cushion property, liquid passage time) of the laminated nonwoven fabric 10.

  As is clear from the results shown in Table 1, each of Examples 1 to 4 obtained good results (evaluation of ◯ marks) in any evaluation item. The cushioning property was 0.93 to 1.14 in terms of WC value, and the liquid passage time was as fast as 3.24 seconds to 5.32 seconds.

  In Comparative Examples 1 to 3, the WC value was 0.53 to 0.78, and the cushioning property was evaluated from Δ to ×. The liquid passage time was 6.37-9.37 seconds, and the evaluation was marked with a cross.

  Therefore, the laminated nonwoven fabric 10 of this embodiment described in Example 1 to Example 4 described above obtained good evaluation results regardless of the first manufacturing method and the second manufacturing method. In particular, the second fiber web 14 is superimposed on the first fiber layer 11 shaped in an uneven shape to form the second fiber layer 12, and the first fiber layer 11 is joined to form a two-layer structure. Therefore, a portion 25 having a low fiber density is formed between the first fiber layer 11 and the second fiber layer 12 of the convex portion 21. As a result, an excellent effect is obtained in that a good cushioning property can be obtained even with a three-dimensional low pressure load. That is, the laminated nonwoven fabric 10 of the present embodiment exhibits a three-dimensional cushioning property that is well supported by a point on both sides following a three-dimensional movement. On the other hand, streak-like projections and single-side projections inevitably exhibit elasticity as lines or surfaces, and lack three-dimensional followability. Moreover, even if it has the part 25 with a low fiber density between the 1st fiber layer 11 used as an upper layer sheet, and the 2nd fiber layer 12 used as a lower layer sheet, joining in the recessed part 22 is a fiber by 3rd hot air W3. Since it is joining by fusion | melting of each other, since a clearance gap is made between fibers, the liquid passage time is shortened and the liquid permeability is excellent. Moreover, since the fiber orientation degree of the 2nd fiber layer 12 is larger than the fiber orientation degree of the 1st fiber layer 11, the moderate cushioning property in which a fiber is not crushed by the 2nd fiber layer 12 is implement | achieved. . Even if the laminated nonwoven fabric 10 is crushed by receiving a pressing force, its shape restoring force is large, and even if the packing state and wearing are continued, it is difficult to lose the initial cushioning force.

DESCRIPTION OF SYMBOLS 10 Laminated nonwoven fabric 11 1st fiber layer 12 2nd fiber layer 13 1st fiber web 14 2nd fiber web 15 Fiber 21 Convex part 21A 1st convex part 21B 2nd convex part 22 A recessed part 22A 1st recessed part 22B 2nd recessed part 23, 24 Wall part 25 Low fiber density part 25

Claims (5)

  An unfused fiber web containing thermoplastic fibers serving as the second fiber layer is laminated on the first fiber layer that is shaped into a concavo-convex shape and includes thermoplastic fibers, and the laminated first fiber layer And by heating the second fiber layer with hot air, the fibers of the fiber web are thermally fused to form a second fiber layer, and the fibers of the first fiber layer and the second fiber layer A laminated nonwoven fabric in which fibers are bonded by heat fusion. The sheet-like laminated nonwoven fabric has a convex portion protruding on the first surface side on the side viewed in plan and a concave concave portion, a plurality of the convex portions are arranged so as to surround the concave portion, and the convex portion and the The concave portions are alternately and continuously arranged in different directions intersecting in plan view of the laminated nonwoven fabric,
A first fiber layer having a concavo-convex shape due to the convex portion and the concave portion on the first surface side, and a first fiber layer joined along a second surface side opposite to the first surface side of the first fiber layer. Two fiber layers,
The laminated nonwoven fabric whose fiber density of the said recessed part is 0.01-0.08 g / cm < ³ >. The convex part of the second fiber layer along the shape of the second fiber side of the convex part of the first fiber layer has an upper part on the first fiber layer side and a lower part on the opposite side, and the first fiber Between the convex part of the layer and the upper part and the lower part of the convex part of the second fiber layer, the order of the fiber density is the convex part of the first fiber layer, the lower part of the convex part of the second fiber layer, The laminated nonwoven fabric according to claim 1 or 2, which is an upper part of the second fiber layer.   The laminated nonwoven fabric according to any one of claims 1 to 3, wherein the degree of fiber orientation of the convex part of the first fiber layer and the convex part of the second fiber layer are different. A first fiber web containing thermoplastic fibers is transported onto a support having an uneven shape and air permeability, and hot air is blown onto the first fiber web to follow the uneven shape. The process of shaping and
While the first fiber web is conveyed along the surface of the support, hot air is blown onto the first fiber web, and the fibers of the first fiber web are shaped into the irregular shape of the support. A previous air-through process in which the first fiber layer is obtained by fusing together,
Laminating the first fiber layer and the second fiber web containing thermoplastic fibers, blowing hot air, and heat-bonding the fibers of the second fiber web together with the shape of the first fiber layer. A method for producing a laminated nonwoven fabric, comprising: obtaining a second fiber layer, and simultaneously performing a subsequent air-through process in which the fibers of the first fiber layer and the second fiber web are bonded together by heat fusion.