JP6289418B2 - Nonwoven fabric for absorbent articles - Google Patents

Description

  The present invention relates to a nonwoven fabric used for absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads.

  In absorbent articles such as disposable diapers and sanitary napkins, a nonwoven fabric containing cotton, which is a natural fiber, has been studied as a nonwoven fabric used for components such as face sheets in order to obtain a sense of security from natural materials. Yes.

  As such a nonwoven fabric, for example, in Patent Document 1, a layer made of short fibers such as thermoplastic resin fibers is laminated on at least one side of a layer mainly made of cotton linter having a fiber length of 5 mm. There has been proposed a short fiber nonwoven fabric in which linters and cotton linters and short fibers are three-dimensionally entangled and integrated with each other.

JP 2001-32157 A

However, like the nonwoven fabric disclosed in Patent Document 1, a laminated nonwoven fabric including a fiber layer made of short fibers such as thermoplastic resin fibers and a fiber layer made of short fibers such as thermoplastic resin fibers and cotton is short. Due to differences in the chemical properties of fibers and cotton (for example, hydrophobicity and hydrophilicity) and physical properties (for example, differences in rigidity), the entanglement between short fibers and cotton is weak and short. Since fibers and cotton are easy to dissociate, when such a laminated nonwoven fabric is used in a product with structural changes (deformation) such as absorbent articles, the fiber layer containing cotton due to the structural change (deformation) of the product The short fibers and cotton were dissociated inside, and the fiber layer was split (decomposed) and delamination was caused between adjacent fiber layers, which could reduce the strength of the laminated nonwoven fabric. In particular, when the above-mentioned laminated nonwoven fabric is used for an absorbent article, if the fiber layer constituting the laminated nonwoven fabric is split (decomposed) or delaminated, fluffing may occur, urine supplied to the absorbent article, It may be difficult to obtain sufficient fluid transfer of body fluid such as blood.
In addition, since cotton has a relatively high fiber rigidity, if the amount of cotton contained in the fiber layer increases, the flexibility of the fiber layer decreases, and the cushioning properties and feel of the laminated nonwoven fabric including the fiber layer are reduced. In addition, there is a possibility that followability to the body shape is impaired.

  Therefore, the present invention relates to a nonwoven fabric for absorbent articles comprising a fiber layer composed of thermoplastic resin fibers and a fiber layer composed of thermoplastic resin fibers and cotton, and is excellent in strength and flexibility and against body fluids such as urine and menstrual blood It aims at providing the nonwoven fabric for absorbent articles which was excellent also in liquid permeability.

  The nonwoven fabric for absorbent articles according to one aspect (Aspect 1) of the present invention includes a first fiber layer containing cotton and thermoplastic resin fibers, and a thermoplastic resin fiber adjacent to at least one surface of the first fiber layer; A non-woven fabric for absorbent articles comprising at least two fiber layers including a second fiber layer not containing cotton, wherein the thermoplastic resin fibers contained in the first fiber layer are in the second fiber layer. The nonwoven fabric has a fiber diameter smaller than that of the thermoplastic resin fiber included, and the nonwoven fabric is formed by a first surface formed by a fiber layer other than the first fiber layer, and the first fiber layer, A second surface opposite to the first surface, extending in the first direction on the first surface of the nonwoven fabric and provided at a predetermined interval in a second direction orthogonal to the first direction. A plurality of protrusions projecting toward the first surface And a plurality of grooves that are recessed in the direction of the second surface, provided between the convex portions that extend in the first direction and are adjacent in the second direction, The groove includes a first recess having a first bottom located on the second surface side relative to a position on the first surface at the top of the convex portion, and is not in the first direction in the first recess. A plurality of second recesses provided continuously from the first bottom portion toward the second surface, wherein the second recess is in the direction from the first bottom portion to the second surface side. And a second bottom portion having the highest fiber density in the nonwoven fabric provided to close the end portion on the second surface side of the peripheral wall portion. Is.

According to the nonwoven fabric for absorbent articles of aspect 1, the thermoplastic resin fibers contained in the first fiber layer have a smaller fiber diameter than the thermoplastic resin fibers contained in the second fiber layer. The thermoplastic resin fiber having a small fiber diameter contained in one fiber layer is easily entangled with the cotton contained in the first fiber layer and the thermoplastic resin fiber contained in the second fiber layer, and the fiber layer is split as described above. In addition, since delamination between fiber layers hardly occurs, even if the nonwoven fabric contains cotton as a constituent component, excellent strength as a nonwoven fabric can be exhibited.
Moreover, the nonwoven fabric for absorbent articles of the aspect 1 has the structure having the specific convex portion and the groove portion, that is, the groove portion is located on the second surface side with respect to the position on the first surface side in the top portion of the convex portion. A first recess having a first bottom portion, a peripheral wall portion extending from the first bottom portion toward the second surface side, and an end portion of the peripheral wall portion on the second surface side so as to block the end portion. Provided with a second concave portion having a second bottom portion having the highest fiber density among the nonwoven fabrics, and the fiber density of the convex portion and the first concave portion is relatively low, and Since the stress in the thickness direction applied from the first surface side of the nonwoven fabric can be buffered by the first recess being bent toward the second surface side, even if the nonwoven fabric includes cotton as a constituent component Enough flexibility can be ensured.
Furthermore, the fiber density of the 2nd bottom part arrange | positioned between the said convex parts is relatively high, The thermoplastic resin fiber with a thin fiber diameter contained in the said 1st fiber layer is contained in the said 1st fiber layer. In order to more closely intertwine with the thermoplastic resin fibers contained in the cotton and the second fiber layer, the above-described fiber layer splitting and delamination between the fiber layers are more unlikely to occur at the second bottom portion. Can do. By providing a plurality of portions (that is, the second bottom portion) that are less likely to cause such fiber layer splitting or delamination between the fiber layers locally in the nonwoven fabric, the fiber layer splitting or Even if the delamination between the fiber layers partially occurs, the fiber layer is not split or delamination between the fiber layers does not occur at the second bottom, and it is possible to effectively prevent the strength of the nonwoven fabric from being lowered as a whole. it can.
In addition, the nonwoven fabric for absorbent articles of aspect 1 has a structure in which a density gradient exists from the convex portion having a relatively low fiber density to the second bottom portion of the second concave portion having the highest fiber density in the thickness direction. Therefore, body fluids such as urine and menstrual blood supplied from the first surface side of the nonwoven fabric are easily drawn from the convex portion on the first surface side of the nonwoven fabric to the second surface side through the second bottom portion. And the absorptivity (especially absorption rate, liquid transferability, etc.) excellent as a nonwoven fabric for absorbent articles can be exhibited.

  The nonwoven fabric for absorbent articles according to another aspect (aspect 2) of the present invention is the nonwoven fabric for absorbent articles according to aspect 1, in which the peripheral wall portion is a pair of first peripheral wall portions along the first direction; A pair of second peripheral wall portions along two directions, and a hole portion communicating with the second surface is provided in at least one of the pair of first peripheral wall portions.

  According to the nonwoven fabric for absorbent articles according to aspect 2, the tension of the fibers forming the adjacent convex portions can be released by the holes in the first peripheral wall portion, so that the entire convex portions or convex portions are formed. The degree of freedom of movement of the fibers to be improved can be improved, and the flexibility of the convex portion can be further improved.

  The nonwoven fabric for absorbent articles according to yet another aspect (aspect 3) of the present invention is the nonwoven fabric for absorbent articles according to aspect 1 or 2, wherein the first surface of the nonwoven fabric is a fiber layer other than the first fiber layer. Is formed.

  According to the nonwoven fabric for absorbent articles of aspect 3, the first surface of the nonwoven fabric used as the skin contact surface of the wearer of the absorbent article is formed by a fiber layer other than the first fiber layer containing cotton. Therefore, the deterioration of the touch by cotton, the fall of a softness | flexibility, etc. can be prevented, and the outstanding touch and softness | flexibility as a nonwoven fabric can be hold | maintained.

  The nonwoven fabric for absorbent articles according to yet another aspect (aspect 4) of the present invention is the nonwoven fabric for absorbent articles according to any one of aspects 1 to 3, wherein the pitch of the second recesses in the second direction is 1.5 mm or less. is there.

  According to the nonwoven fabric for absorbent articles of aspect 4, since the pitch in the second direction of the second recesses is 1.5 mm or less, the cotton in the first fiber layer is the second of the second recesses. It is easy to be held at the bottom, and it is possible to make the fiber layer splitting and delamination between the fiber layers more difficult to occur at the second bottom. Therefore, a nonwoven fabric that is particularly excellent in strength and liquid permeability can be obtained.

  The nonwoven fabric for absorbent articles according to yet another aspect (aspect 5) of the present invention is the nonwoven fabric for absorbent articles according to any one of aspects 1 to 4, wherein the nonwoven fabric forms the second surface. Including the second fiber layer adjacent to the first surface side surface of the first fiber layer, the thermoplastic resin fiber adjacent to the first surface side surface of the second fiber layer, and cotton Each of the fiber layers has the same basis weight of the thermoplastic resin fiber, and the thermoplastic resin fiber included in the third fiber layer is included in the second fiber layer. The fiber diameter is the same as or larger than that of the thermoplastic resin fiber.

  In general, in the fiber layer containing cotton, when the cotton raw material is defibrated, it is easy for the lump of cotton that has not been defibrated to remain, and this lump of cotton causes the entanglement with the surrounding fibers to be released. As a result, the strength of the fiber layer may be reduced. However, according to the nonwoven fabric for absorbent articles of aspect 5, each fiber layer has the same basis weight of the thermoplastic resin fiber, and is included in the second fiber layer and the third fiber layer. Since the nonwoven fabric is comprised so that the resin fiber may have a fiber diameter larger than the thermoplastic resin fiber contained in the said 1st fiber layer, the said 1st fiber layer is the thermoplastic contained in the said 1st fiber layer. The amount of resin fibers (number of fibers) is greater than that of the second fiber layer and the third fiber layer, and the strength of the first fiber layer containing cotton can be improved. Moreover, the nonwoven fabric for absorbent articles of aspect 5 is a fiber whose fiber amount (number of fibers) increases in the thickness direction from the first surface to the second surface (that is, from the third fiber layer to the first fiber layer). Since it has a structure in which there is a quantity gradient (or a fiber density gradient in which the fiber density increases from the first surface to the second surface (from the third fiber layer to the first fiber layer)), Body fluids such as urine and menstrual blood supplied to the surface on the first surface side are easily drawn from the first surface side to the second surface side of the non-woven fabric, and as a non-woven fabric for absorbent articles, an even better absorbency ( In particular, the absorption rate and liquid transferability can be exhibited.

  According to the present invention, the nonwoven fabric for absorbent articles includes a fiber layer made of thermoplastic resin fibers and a fiber layer made of thermoplastic resin fibers and cotton, and has excellent strength and flexibility, urine, menstrual blood, etc. The nonwoven fabric for absorbent articles which is excellent also in the liquid permeability with respect to the body fluid of this can be provided.

FIG. 1 is a perspective view of a nonwoven fabric for absorbent articles according to an embodiment of the present invention. FIG. 2 is a plan view of the nonwoven fabric for absorbent articles according to one embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of a cross section taken along the line III-III ′ shown in FIG. 2 of the nonwoven fabric for absorbent articles according to one embodiment of the present invention. Fig.4 (a) is an expanded sectional view of the cross section along the IV-IV 'line | wire shown in FIG. 2 of the nonwoven fabric for absorbent articles which concerns on one Embodiment of this invention, FIG.4 (b) is FIG. It is a principal part expansion schematic diagram of the cross section of the nonwoven fabric for absorbent articles shown to (a). Drawing 5 is a mimetic diagram for explaining an example of the manufacture device of the nonwoven fabric for absorptive articles concerning the present invention. FIG. 6 is an enlarged perspective view of a main part schematically showing a pair of shaping rolls of the shaping device provided in the apparatus for manufacturing a nonwoven fabric for absorbent articles according to the present invention. FIG. 7 is an enlarged schematic view of the main part showing the arrangement of the pins of the lower shaping roll in the pair of shaping rolls shown in FIG. 6. FIG. 8 is an enlarged schematic view of the main part showing the meshing state of the upper shaping roll and the lower shaping roll in the pair of shaping rolls shown in FIG. 6.

  Hereinafter, preferred embodiments of the nonwoven fabric for absorbent articles according to the present invention will be described in detail with reference to the drawings.

1-4 is a figure which shows typically the nonwoven fabric 1 for absorbent articles which concerns on one Embodiment of this invention. In the present specification, unless otherwise specified, viewing the unfolded nonwoven fabric in the thickness direction _DT from the upper surface side is simply referred to as “plan view”.

As shown in FIGS. 1-4, the nonwoven fabric 1 for absorbent articles which concerns on 1st embodiment of this invention is the lower surface 1b which is the upper surface 1a which is a 1st surface, and the 2nd surface on the opposite side to this upper surface 1a. The first fiber layer 2 including the cotton 2a and the thermoplastic resin fibers 2b, and adjacent to the surface on the upper surface 1a side of the first fiber layer 2, It is a fiber layer that forms the upper surface 1a, and is constituted by a two-layer fiber laminate including the second fiber layer 3 that includes the thermoplastic resin fiber 3a and does not include cotton, and the nonwoven fabric 1 Is a specific concavo-convex structure to be described later, that is, provided at a predetermined interval in a second direction D ₂ extending in the first direction D ₁ and orthogonal to the first direction D ₁ on the upper surface 1a. A plurality of convex portions 4 projecting in the direction of the upper surface 1a, and the first Provided between the convex portions 4 adjacent in the direction D ₁ to extend in and the second direction D _2, and a plurality of grooves 5 recessed in the direction of the lower surface 1b, the The groove portion 5 includes a first recess portion 51 having a first bottom portion 51a located on the second surface 1b side of the top portion 41 of the protrusion portion 4 on the first surface 1a side, and in the first recess portion 51. provided discontinuously in the first direction D ₁ at has a plurality of second recesses 52 recessed in the direction of the second surface 1b of the first bottom portion 51a, further, the The second recess 52 closes an end portion of the peripheral wall portion 52a extending from the first bottom portion 51a in the direction of the second surface 1b and an end portion of the peripheral wall portion 52a on the second surface 1b side. Provided with a second bottom portion 52b having the highest fiber density among the nonwoven fabrics 1 And has a specific uneven structure.

  The absorbent article to which the nonwoven fabric for absorbent articles of the present invention is applied is not particularly limited, and examples thereof include various absorbent articles such as tape-type or pant-type disposable diapers, sanitary napkins, panty liners, and the like. it can. The nonwoven fabric for absorbent articles of the present invention can be used as, for example, a sheet material attached to the outer surface of a backsheet such as a disposable diaper. In particular, absorbent articles such as disposable diapers and sanitary napkins are used. It can be suitably used as a sheet material that may come into contact with the skin of the wearer, such as a surface sheet or a leak-proof wall.

  In addition, when the nonwoven fabric for absorbent articles of this invention is applied to the surface sheet etc. of an absorbent article, the 1st surface provided with the convex part faces a wearer's skin from the point of touch or a softness | flexibility. It is preferable to be arranged as described above.

  The fiber laminated body which comprises the nonwoven fabric 1 for absorbent articles which concerns on one Embodiment of this invention is the 1st fiber layer 2 containing the cotton 2a and the thermoplastic resin fiber 2b, and the upper surface 1a side of the said 1st fiber layer 2 Although it is a fiber layer that is adjacent to the surface and forms the upper surface 1a, and includes the second fiber layer 3 that includes the thermoplastic resin fibers 3a and does not include cotton, the fiber layer is formed of a two-layer fiber laminate. In the present invention, the fiber laminate is not limited to the two-layer fiber laminate, and may be a fiber laminate including three or more fiber layers including the first fiber layer and the second fiber layer. .

  In the present invention, the cotton contained in the first fiber layer is not particularly limited. For example, cotton having a fineness in the range of 1.0 to 15 dtex and a fiber length in the range of 5 to 40 mm is used. be able to. Among these, when the fiber length is 20 mm or more, when the first fiber layer is laminated with the second fiber layer described later (that is, when a fiber laminate is formed), a part of the cotton fiber is the second fiber. Since it is easy to enter the layer and the liquid permeability of the nonwoven fabric can be improved, it can be suitably used. In addition, a mixed cotton obtained by mixing a cotton having a fiber length of 20 mm or more and a cotton having a fiber length of 10 mm or less can improve the liquid permeability of the nonwoven fabric with the cotton having a fiber length of 20 mm or more. However, since the bulk of the nonwoven fabric can be increased by cotton having a thickness of 10 mm or less, it can be particularly preferably used.

  The content of cotton in the first fiber layer is not particularly limited, but is within the range of, for example, 1 to 70% by mass, preferably 2 to 30% by mass from the viewpoint of water absorption, water retention, flexibility, and the like. Within range.

In the present invention, the thermoplastic resin fiber contained in the first fiber layer is not particularly limited as long as it is a fiber made of a thermoplastic resin. Examples of the thermoplastic resin include polyethylene (PE), polypropylene (PP ), Olefin resins such as ethylene-vinyl acetate copolymer (EVA), polyester resins such as polyethylene terephthalate (PET) and polylactic acid (PLA), and polyamide resins such as 6-nylon. These resins may be used alone or in combination of two or more resins.
Further, the structure of the fiber made of such a thermoplastic resin is not particularly limited. For example, a composite fiber such as a core-sheath type fiber, a side-by-side type fiber, an island / sea type fiber; a hollow type fiber; Non-uniform cross-section type fibers such as flat, Y-shaped and C-shaped; three-dimensional crimped fibers of latent crimp or actual crimp; split fibers divided by physical load such as water flow, heat, embossing, etc. The fibers having a structure may be used alone or two or more kinds of fibers may be used in combination.

  The fineness (fiber diameter) of the thermoplastic resin fiber is not particularly limited as long as it is thinner than the fiber diameter of the thermoplastic resin fiber contained in the second fiber layer described later, but the strength and flexibility of the nonwoven fabric, the touch, From the viewpoint of liquid permeability, it is usually in the range of 1.1 to 8.8 dtex, and preferably in the range of 1.5 to 4.6 dtex.

  The fiber length of the thermoplastic resin fiber is not particularly limited, but is usually in the range of 20 to 100 mm, preferably in the range of 35 to 65 mm, from the viewpoint of the strength, flexibility, liquid permeability and the like of the nonwoven fabric. It is. The thermoplastic resin fiber may be subjected to a hydrophilic treatment. Examples of such a hydrophilic treatment include a treatment using a surfactant, a hydrophilic agent, etc. (for example, a surfactant into the fiber interior). Kneading, application of a surfactant to the fiber surface, etc.).

  Although the content of the thermoplastic resin fiber in the first fiber layer is not particularly limited, it is, for example, in the range of 30 to 99% by mass, preferably 70 to 98% by mass, from the viewpoint of the strength and flexibility of the nonwoven fabric. Is within the range.

  Moreover, the said 1st fiber layer may contain fibers other than the said cotton and a thermoplastic fiber, arbitrary additives, etc. in the range which does not inhibit the effect of this invention.

Next, the said 2nd fiber layer which comprises the nonwoven fabric for absorbent articles of this invention is demonstrated. The thermoplastic resin fiber contained in the second fiber layer is not particularly limited except that it has a fiber diameter larger than that of the thermoplastic resin fiber contained in the first fiber layer, and any thermoplastic resin fiber is used. However, in terms of ease of entanglement between fibers, fibers other than the fiber diameter (fineness) are the same as the thermoplastic resin fibers contained in the first fiber layer (that is, included in the first fiber layer). It is preferable to use a fiber (made of the same material (resin) as the thermoplastic resin fiber that has the same fiber length).
In addition, the said 2nd fiber layer may contain fibers other than the said thermoplastic fiber, arbitrary additives, etc. in the range which does not inhibit the effect of this invention.

  In the present invention, since the thermoplastic resin fiber contained in the first fiber layer has a fiber diameter smaller than that of the thermoplastic resin fiber contained in the second fiber layer, it is contained in the first fiber layer. The thermoplastic resin fiber having a small fiber diameter is easily entangled with the cotton contained in the first fiber layer and the thermoplastic resin fiber contained in the second fiber layer. Since delamination hardly occurs, even if the nonwoven fabric contains cotton as a constituent component, excellent strength as a nonwoven fabric can be maintained.

  In this invention, the fiber laminated body which comprises the nonwoven fabric for absorbent articles is not limited to the two-layer laminated body which concerns on the above-mentioned embodiment, Three or more fiber layers according to desired absorptivity, a softness | flexibility, etc. The laminated body which consists of may be sufficient. Moreover, as for the nonwoven fabric for absorbent articles of this invention, it is preferable that the 1st surface of the said nonwoven fabric is formed of fiber layers other than the 1st fiber layer containing cotton irrespective of the number of layers of a fiber laminated body. When the first surface serving as the skin contact surface of the wearer of the absorbent article is formed by a fiber layer other than the first fiber layer containing cotton, the deterioration of the touch and the decrease in flexibility due to the cotton are prevented. And can maintain excellent touch and flexibility as a non-woven fabric.

  In the nonwoven fabric for absorbent articles of the present invention, the other fiber layers other than the first fiber layer and the second fiber layer are not particularly limited. For example, natural fibers such as wool, regenerated fibers such as rayon, inorganic Examples thereof include a fiber layer made of synthetic resin fibers such as fibers and thermoplastic resin fibers. In addition, the other fiber layer may contain arbitrary additives etc. within the range which does not inhibit the effect of this invention.

In the present invention, the basis weight of each fiber layer constituting the nonwoven fabric for absorbent articles is not particularly limited, but is 1 to 60 g / m ² , for example, from the viewpoint of strength, flexibility, absorbability, and the like of the nonwoven fabric. in the range, preferably in the range of 10 to 30 g / m ^2. Although the basic weight as a nonwoven fabric for absorbent articles is not particularly limited, it is usually in the range of 10 to 100 g / m ² , preferably in the range of 15 to 75 g / m ² , and more preferably 20 to 50 g. / M ² .
The thickness of the nonwoven fabric for absorbent articles of the present invention is not particularly limited, but is usually in the range of 0.1 to 5 mm, preferably in the range of 0.5 to 3 mm, more preferably 0.8 to. Within the range of 2 mm.

In the nonwoven fabric for absorbent articles according to another embodiment of the present invention, the nonwoven fabric is formed on the first fiber layer forming the second surface of the nonwoven fabric, and on the first surface side surface of the first fiber layer. Each fiber layer is constituted by the adjacent second fiber layer and a third fiber layer that includes a thermoplastic resin fiber and does not include cotton adjacent to a surface on the first surface side of the second fiber layer. The thermoplastic resin fibers have the same basis weight, and the thermoplastic resin fibers contained in the third fiber layer have a fiber diameter (fineness) equal to or greater than that of the thermoplastic resin fibers contained in the second fiber layer. ).
In the nonwoven fabric for absorbent articles according to this embodiment, the amount (number of fibers) of the thermoplastic resin fibers contained in the first fiber layer is larger than that of the second fiber layer and the third fiber layer, and therefore cotton. The strength of the first fiber layer containing can be further improved. In addition, in such a nonwoven fabric, the amount of fibers (the number of fibers) increases in the thickness direction from the first surface to the second surface of the nonwoven fabric (that is, from the third fiber layer to the first fiber layer). Since it has a structure with a gradient (or a fiber density gradient in which the fiber density increases from the first surface to the second surface (from the third fiber layer to the first fiber layer)), Body fluids such as urine and menstrual blood supplied to the surface on the first surface side are easily drawn from the first surface side to the second surface side of the non-woven fabric, and as a non-woven fabric for absorbent articles, an even better absorbency ( In particular, the absorption rate and liquid transferability can be exhibited.

Next, the manufacturing method of the fiber laminated body before the uneven | corrugated shaping process (before forming an uneven | corrugated structure) which comprises the nonwoven fabric for absorbent articles of this invention is demonstrated.
In the present invention, means for producing the fiber laminate is not particularly limited. For example, fibers for forming the fiber layers (that is, cotton and thermoplastic resin fibers for forming the first fiber layer, The web (fleece) corresponding to each fiber layer is formed using a thermoplastic resin fiber for forming the second fiber layer, etc., and the fibers in each web and between the webs are physically or chemically connected to each other. The method of combining is mentioned.

Specifically, a two-layer fiber laminate including the first fiber layer and the second fiber layer can be manufactured according to the following procedure.
(1) A conveying device that conveys a sheet-like member in one direction, a first-stage carding device that is arranged upstream of the conveying device and upstream of the conveying direction, and a conveying direction above the conveying device. A second-stage carding device disposed downstream (ie, downstream from the first-stage carding device), and an air-through heating device disposed downstream of the second-stage carding device The manufacturing apparatus provided with is prepared.
(2) The thermoplastic resin fibers for forming the second fiber layer are supplied to the first-stage carding apparatus, and the thermoplastic resin fibers are opened by pins of a rotating roll in the carding apparatus. Then, a web corresponding to the second fiber layer is formed on the transport surface of the transport device.
(3) While the web corresponding to the second fiber layer formed on the transport surface of the transport device is transported downstream in the transport direction, the first fiber layer is placed on the second stage carding device. Cotton for forming and thermoplastic resin fibers are supplied, each fiber is opened by a pin of a rotating roll in the carding device, and the web corresponding to the first fiber layer is transported to the second It forms on the web corresponding to a fiber layer.
(4) A laminated web in which a web corresponding to the first fiber layer is laminated on a web corresponding to the second fiber layer is conveyed to the air-through heating device, and in each heating web, The first fiber layer and the second fiber layer are obtained by entanglement of fibers between webs, arbitrarily heat-sealing the thermoplastic resin fibers, and fusing and fixing cotton to the surface of the thermoplastic resin fibers. Can be produced.

  In addition, when manufacturing the fiber laminated body which consists of three or more fiber layers, it can manufacture like the said procedure using the manufacturing apparatus which has arrange | positioned the carding apparatus 3 steps | paragraphs or more.

  The formation method of the web corresponding to each fiber layer is not limited to the above-mentioned method, For example, you may employ | adopt a wet method etc. Further, the web joining method is not limited to the above-described method, and for example, a hydroentanglement method or a needle punch method may be employed.

  The fiber laminate produced in this manner is given the above-mentioned specific concavo-convex structure by the concavo-convex shaping process described later, and the nonwoven fabric for absorbent articles of the present invention is obtained.

  Next, the uneven structure of the nonwoven fabric for absorbent articles of the present invention will be described in more detail with reference to the drawings.

1-4, as for the nonwoven fabric 1 for absorbent articles which concerns on one Embodiment of this invention, the area | region of the 1st surface 1a which makes the convex part 4, and the area | region of the 2nd surface 1b are the 2nd surface 1b side. It is the structure curved in the shape which becomes convex toward the direction of the 1st surface 1a side. On the other hand, the first recess 51 of the groove 5 is such that the region of the first surface 1a and the region of the second surface 1b forming the first recess 51 are directed from the first surface 1a side to the second surface 1b side. It has a configuration curved into a convex shape. Therefore, the nonwoven fabric 1 has a sheet shape with a substantially corrugated cross section in which irregularities are alternately repeated with respect to a second direction D ₂ orthogonal to the first direction D ₁ in which the convex portions 4 are extended.

The convex portion 4 extends in the first direction D ₁ (for example, the longitudinal direction of the nonwoven fabric) of the surface (sheet surface) of the nonwoven fabric 1 and the first direction D of the surface of the nonwoven fabric 1. _A plurality of rows are arranged at predetermined intervals in a second direction D ₂ orthogonal to ₁ (for example, the width direction of the nonwoven fabric). In the present embodiment, the protrusions 4 are all have also been extended so as to be parallel to each other and continuously and the other convex portion 4 toward the first direction D _1.

In the nonwoven fabric for absorbent articles of the present invention, the convex portion preferably has an interval between adjacent convex portions of 0.25 to 5 mm, more preferably 0.5 to 3 mm, and more preferably. Is 0.75 to 2 mm. Here, "the distance between the convex portions adjacent" refers to the distance between the substantially center position in the second direction D ₂ of each of the convex portions (apexes of the substantially convex portion).
If the distance between adjacent convex portions is less than 0.25 mm, the uneven structure of the nonwoven fabric is too fine, and the contact area between the convex portions of the nonwoven fabric and the wearer's skin cannot be reduced so much. On the other hand, when the distance between the adjacent convex portions exceeds 5 mm, the surface of the surface (first surface) may be reduced. Since the difference in structure is reduced, it becomes difficult to obtain a soft touch utilizing the uneven structure.

  In the nonwoven fabric for absorbent articles of the present invention, the convex portion has a length from the height on the first surface side of the first bottom portion of the first concave portion to the height of the top portion of the convex portion (that is, the height of the convex portion). ) Is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and even more preferably 0.75 to 2 mm. If the height of this convex part is less than 0.25 mm, the protrusion of the convex part is too small, so it becomes difficult to obtain a soft touch utilizing the concave-convex structure, while the height of the convex part exceeds 5 mm, Since the protrusion of the convex portion is too large and becomes a sharp structure, it is difficult to obtain a soft touch.

As shown in FIGS. 1-4, the absorbent article for nonwoven fabric 1 according to an embodiment of the present invention, the space between the second direction D ₂ adjacent with respect to the convex portions 4, the groove 5 is first 1 it is provided so as to extend in the direction D _1, the groove 5, the including a first bottom portion 51a located in the direction of the second surface 1b than the position of the first surface 1a at the top 41 of the convex portion 4 1 recess 51 and a plurality of second recesses 52 that are discontinuously provided in the first direction D ₁ in the first recess 51 and are recessed from the first bottom 51 a toward the second surface 1 b. And have.

  The nonwoven fabric for absorbent articles of the present invention has such a structure having specific convex portions and groove portions, that is, the groove portions are located on the second surface side with respect to the position on the first surface side at the top of the convex portions. A first recess having a first bottom portion, a peripheral wall portion extending from the first bottom portion toward the second surface side, and an end portion of the peripheral wall portion on the second surface side so as to block the end portion. Provided with a second concave portion having a second bottom portion, so that the stress in the thickness direction applied from the first surface side of the non-woven fabric, the first concave portion is on the second surface side. Therefore, even a non-woven fabric containing cotton as a constituent component can sufficiently ensure flexibility.

In one embodiment of the present invention, the second recess 52 has a substantially rectangular opening in plan view, and protrudes toward the lower surface 1b of the nonwoven fabric 1 as a whole, thereby forming a substantially rectangular parallelepiped internal space. It has become a preparation. The second recesses 52 are arranged at regular intervals in the length direction of each groove 5 (that is, the first direction D ₁ or the length direction of the first recess 51). The recess 52 is formed in a state independent of the other second recess 52.

Further, in the present embodiment, the plurality of second recesses 52 are respectively formed on a peripheral wall portion 52a having a standing wall shape extending toward the lower surface 1b in a state of being continuous with the first bottom portion 51a, and on a lower end side of the peripheral wall portion 52a. The above-described second bottom portion 52b is provided. The peripheral wall portion 52a has a pair of first peripheral wall portion _52a 1 extending along the first direction _{D 1,} 52a ₁ and the second pair extending along the direction _{D 2} second peripheral wall portion _52a 2, 52a ₂ , the pair of first peripheral wall portions 52a ₁ , 52a ₁ are disposed at positions facing each other, and the pair of second peripheral wall portions 52a ₂ , 52a ₂ are also positioned at positions facing each other. It is arranged.

As shown in FIGS. 1 and 3, the pair of first peripheral wall portions 52a ₁ and 52a ₁ are respectively formed with hole portions 53 that lead from the internal space of the first recess 51 to the second surface 1b. In the present embodiment, one hole portion 53 is provided in each of the pair of first peripheral wall portions 52a ₁ and 52a ₁ , and these hole portions 53 are the second bottom portions in the first peripheral wall portion 52a ₁ . It is formed at a position closer to 52b (therefore, two first holes 51 are present in one first recess 51). On the other hand, the pair of second peripheral wall portions 52a ₂ and 52a ₂ does not have a portion corresponding to the hole portion 53, and each of the second peripheral wall portions 52a ₂ is directly on the lower end side directly with the second bottom portion 52b. It is in the state connected to.

In the nonwoven fabric for absorbent articles of the present invention, the second recessed portion reduces the chance that the groove bottom of the groove portion, more specifically, the first bottom portion of the first recessed portion contacts the skin of the wearer of the absorbent article as much as possible. Even if the first bottom touches the wearer's skin, it is provided in order to minimize the contact area. That is, the nonwoven fabric for absorbent articles of the present invention has a structure in which the skin of the wearer is easily touched in the order of the convex portion and then the first bottom portion of the first concave portion, and the convexity having the highest flexibility among the nonwoven fabrics. Although the part has a desirable structure that it is easier to touch the wearer's skin than the first bottom part, the nonwoven fabric for absorbent articles of the present invention has a smaller contact area that touches the wearer's skin In consideration of the fact that it is easy to feel flexibility, the portion that contacts the wearer's skin at the first bottom portion of the first recess is formed by forming the above-described second recess and forming the portion where the first recess does not exist. The amount of contact with the skin and the contact area are reduced as much as possible.
Further, in the present invention, the second recess is provided at the first bottom of the first recess so as to make it less likely to cause a sense of incongruity or a foreign object due to contact with the second recess, and the second recess is worn by the second recess. The opportunity to touch the person's skin is minimized.

  In the present invention, the depth of the second recess, that is, the length from the height of the first bottom of the first recess on the first surface (upper surface) side to the height of the second bottom of the second recess on the first surface side. Is preferably 0.05 to 2 mm, more preferably 0.075 to 1.5 mm, and still more preferably 0.1 to 1 mm. When the depth of the second recess is less than 0.05 mm, it is difficult to ensure the rigidity of the second bottom described later, and the strength in the thickness direction of the nonwoven fabric tends to be insufficient. On the other hand, when the depth of the second recess exceeds 2 mm, the strength in the thickness direction tends to be insufficient when pasted with other members of the absorbent article (for example, an absorbent body, a nonwoven fabric, a film, etc.) When compressed, there is a possibility that stiff intuition will arise.

  Further, the relationship between the depth of the second recess and the height of the projection is such that the depth of the second recess (that is, the height of the second recess from the height of the first surface of the first bottom of the first recess). 2 is the length from the height of the first bottom side of the first recess to the height of the top of the projection. 10) to 80%, more preferably 15 to 70%, and even more preferably 20 to 60%. If the depth of the second concave portion is less than 10% of the height of the convex portion, a sufficient space for forming the hole portion in the peripheral wall portion of the second concave portion cannot be secured, so the hole portion is insufficient. It is difficult to obtain excellent flexibility as a nonwoven fabric. On the other hand, if the depth of the second recess exceeds 80% of the height of the projection, the hole portion is formed excessively large, so that the strength of the peripheral wall portion of the second recess is reduced and fluffing occurs. It becomes easy and the touch of a nonwoven fabric may fall.

  The length of the second recess in the first direction is not particularly limited, but is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and more preferably 0.75 to 2 mm. is there. If the length of the second recess in the first direction is less than 0.25 mm, the second recess becomes too small, and the above-described action exerted by the second recess may not be sufficiently obtained. There is. When the length of the second recess in the first direction exceeds 5 mm, the second recess becomes too long in the first direction, and it is difficult to differentiate in flexibility compared to a flat nonwoven fabric or a nonwoven fabric without a recess. It becomes difficult to obtain a soft touch.

On the other hand, the length of the second recess in the second direction is not particularly limited, but is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and more preferably 0.75 to 2 mm. If the length of the second recess in the second direction is less than 0.25 mm, the second recess becomes too small, and particularly the second bottom is insufficiently formed. There is a possibility that the above-described action is not sufficiently obtained. If the length of the second recess in the second direction exceeds 5 mm, the second recess becomes excessively large, and there is a possibility that a sense of incongruity or a foreign object is likely to occur when contacting the nonwoven fabric.
Further, the pitch of the second recesses in the second direction (that is, the distance between the second recesses adjacent in the second direction) is not particularly limited, but is preferably 1.5 mm or less. If the pitch of the second recesses in the second direction is 1.5 mm or less, the cotton in the first fiber layer constituting the nonwoven fabric is easily held on the second bottom of the second recesses, At the two bottoms, it is possible to make the fiber layer splitting and delamination between the fiber layers as described above more difficult to occur.

  In the present invention, the hole formed in the peripheral wall portion of the second recess has a maximum length of the hole (in the case of the present embodiment, the length in the first direction) is larger than the second recess. Although it depends, it is preferable that it is 0.25-5 mm, More preferably, it is 0.5-3 mm, More preferably, it is 0.75-2 mm. When the length of the maximum portion of the hole is less than 0.25 mm, the formation of the hole is insufficient, and the flexibility of the second recess cannot be sufficiently secured, and the fibers in the protrusion It is difficult to reduce the tensile force of the projection, and the flexibility of the convex portion cannot be sufficiently secured. When the length of the maximum portion of the hole exceeds 5 mm, the hole becomes too large, the peripheral edge of the hole is likely to fluff, and when it comes into contact with the non-woven fabric, a sense of incongruity or foreign matter is likely to occur. There is a risk of lowering the touch.

  On the other hand, the maximum length in the height direction of the hole (that is, the thickness direction of the nonwoven fabric) is preferably 0.1 to 5 mm, more preferably 0, although it depends on the depth of the second recess. It is 25-3 mm, More preferably, it is 0.5-2 mm. If the maximum length in the height direction of the hole is less than 0.1 mm, the formation of the hole becomes insufficient, and the flexibility of the second recess cannot be sufficiently secured. The tensile force of the fiber is difficult to decrease, and the flexibility of the convex portion cannot be sufficiently ensured. When the maximum length in the height direction of the hole exceeds 5 mm, the hole becomes too large, and the peripheral edge of the hole is likely to fluff, causing a sense of incongruity or a foreign object when contacting the nonwoven fabric. It is easy to cause the touch of the nonwoven fabric to be lowered.

  In the present invention, the hole portion releases the tensile force of the fiber in the convex portion to improve the degree of freedom of movement of the entire convex portion or the fibers forming the convex portion, and more specifically, the flexibility of the convex portion. Flexibility in the thickness direction of the nonwoven fabric at the convex portion, and flexibility when the skin is slid in the first direction (longitudinal direction) and the second direction (width direction) of the nonwoven fabric (especially in the width direction) Is provided only on the first peripheral wall portion of the second recess. Due to the formation of the holes, the protrusions have excellent hardness and softness (excellent softness in the thickness direction of the nonwoven fabric) and excellent rough feeling in the second direction of the nonwoven fabric (planar direction of the nonwoven fabric ( In particular, both excellent smoothness in the second direction) can be imparted, and excellent softness and coarseness can be secured as a whole nonwoven fabric, and a soft touch can be obtained.

Further, in the present invention, when the skin is slid in the first direction of the nonwoven fabric (that is, the direction in which the convex portion and the groove portion extend), the step caused by the second concave portion is less likely to be caught on the skin. In order to ensure smoothness in the first direction, no hole is formed in the second peripheral wall of the second recess.
That is, since the second peripheral wall portion is continuous with the first bottom portion of the first recess and the second bottom portion of the second recess and is integrated seamlessly, the skin is slid in the first direction of the nonwoven fabric. In this case, the skin is likely to move smoothly along the convex part and the groove part without feeling the level difference of the second concave part. Thereby, the smoothness in the 1st direction of the nonwoven fabric which utilized the softness | flexibility of a convex part and the softness | flexibility of a fiber is securable.

  Furthermore, in the present invention, the hole portion is kept as far as possible from the convex portion where the skin is easy to touch and the first bottom portion of the first concave portion, and the opportunity for the wearer's skin to touch the hole portion is reduced as much as possible, thereby making it unlikely to cause a sense of incongruity or foreign matter. Therefore, it is formed at a position near the second bottom portion in the first peripheral wall portion of the second recess. Thereby, the smoothness at the time of sliding skin in the plane direction of a nonwoven fabric can be ensured more stably.

In the nonwoven fabric for absorbent articles according to this embodiment, the hole portion 53 is formed by breaking the thermoplastic resin fiber without melting the thermoplastic resin fiber contained in the nonwoven fabric 1. 53a. More specifically, as shown in FIG. 3, a broken fiber 54 having a broken end portion 54 a formed by breakage among the thermoplastic resin fibers included in the nonwoven fabric 1 at the peripheral portion 53 a of the hole 53. The broken end portion 54a is included.
Therefore, the peripheral portion 53a of the hole portion 53 does not have any portion where the thermoplastic resin fiber is cured by melting, and is a part of the flexible thermoplastic resin fiber or a break formed by the breakage of the thermoplastic resin fiber. It is formed by the broken fiber 54 having the end portion 54a. As a result, even if the skin of the wearer of the absorbent article touches the peripheral portion 53a of the hole 53, since there is no thermoplastic resin fiber cured by melting, it is possible to feel the hardness and roughness of the nonwoven fabric. Deterred as much as possible.

Here, break fiber 54 is part of a fiber of the thermoplastic resin fibers forming the first peripheral wall portion 52a _1, the thermoplastic resin fiber, pulling in the longitudinal direction, or physically disconnect And having a broken end portion 54a formed by breaking.
Therefore, the broken end portion 54a is not such that the end portion of the fiber is melted and rounded to increase the fiber diameter as in the case where the thermoplastic resin fiber is melted. It is a mode in which the taper is reduced or the fiber diameter hardly changes. Thereby, even if it is a case where a wearer's skin touches the peripheral part 53a of the hole 53, it is suppressed that the sense of incongruity resulting from a wrinkle or a fiber catching is produced.

Further, as shown in FIG. 3, some of the thermoplastic resin fibers 55 are bridged over the internal space 53 b of the hole 53. Further, some of the broken fibers 54 are in a state in which the broken end portion 54 a extends into the internal space 53 b of the hole 53.
Therefore, in the internal space 53b of the hole portion 53, the fiber 55 spanned in the internal space 53b and a part of the extended fiber are mixed, and the completely open space It is not. In this way, when a part of the thermoplastic resin fiber is stretched over the internal space of the hole, even if the skin of the wearer touches the hole, The stretched thermoplastic resin fibers can minimize the difference in feel between the peripheral surface of the recess and the bottom and the hole, thereby making it difficult for the wearer to feel uncomfortable. That is, the thermoplastic resin fiber spanned in the internal space of the hole functions so that the skin of the wearer does not completely pass through the hole and reach the second surface side (lower surface side) of the nonwoven fabric. Even when the step between the peripheral wall or the second bottom and the hole is reduced in tactile sensation, the non-woven fabric feels relatively smooth and the wearer's skin touches the hole. It is possible to make it difficult for a person to feel discomfort.

In this invention, it is preferable that the aperture ratio of the internal space of the said hole part is 1-50%, More preferably, it is 1.5-35%, More preferably, it is 2.5-20%. When the opening ratio of the internal space of the hole is less than 1%, the opening ratio is too low to provide a degree of freedom to the protrusions and the fibers in the protrusions, and the protrusions have sufficient flexibility. Can not be secured. If the opening ratio of the internal space of the hole portion exceeds 50%, the strength of the peripheral wall portion provided with the hole portion (the first peripheral wall portion 52a _{1 in} the present embodiment) is likely to be reduced, and the hole portion There is a possibility that the boundary between the peripheral portions is easily recognized on the touch. However, the open area ratio of the internal space of the hole may be outside the above range depending on the type and application of the absorbent article using the nonwoven fabric, and can be arbitrarily set.

Hereinafter, the manufacturing method of the nonwoven fabric 1 for absorbent articles having the specific uneven structure will be described in detail with reference to the drawings.
FIGS. 5-8 shows an example of the manufacturing apparatus which manufactures the nonwoven fabric 1 for absorbent articles, and the manufacturing apparatus 6 is the 1st fiber layer 2 containing the cotton 2a and the thermoplastic resin fiber 2b, and said 1st. Absorption having a specific concavo-convex structure, comprising a fiber laminate 7 composed of two fiber layers adjacent to one side of the fiber layer 2 and including the second fiber layer 3 including the thermoplastic resin fiber 3a and not including cotton. It is an apparatus for processing into the nonwoven fabric 1 for property articles. The manufacturing device 6 is unwound by the unwinding device 61 and the unwinding device 61 in which the unprocessed fiber laminate 7 is wound in a roll shape and unwinds the fiber laminate 7 in the conveying direction MD. A preheating device 62 that preheats the fiber laminate 7, and unevenness extension for stretching the fiber laminate 7 that has been preheated to form convex portions and groove portions (including the first concave portion and the second concave portion). And a shaping device 63 that performs shaping.

  In the present embodiment, the preheating device 62 includes a pair of upper and lower heating rolls 62a and 62b, and is rotating below the fiber laminate 7 to be processed that has been unwound from the unwinding device 61 and conveyed. After being wound around the heating roll 62b and heated, it is transferred to the rotating upper heating roll 62a, and the fiber laminate 7 can be heated by the heating roll 62a.

Further, the shaping device 63 includes a pair of upper and lower stretching rolls 63a and 63b, and the upper stretching roll 63a is disposed at regular intervals in the roll width direction as shown in FIG. Ridges 63a ₁ provided in a plurality of rows in parallel with each other along the outer peripheral surface of the extending roll 63a, and a plurality of rows of concave grooves 63a ₂ provided between two adjacent ridges 63a ₁ and 63a ₁ It has. On the other hand, the stretching roll 63b downward, as shown in FIGS. 6 and 7, the outer peripheral surface 63b _2, includes a plurality of pins 63b ₁ provided so as to mesh with the grooves 63a ₂ of the upper draw roll 63a Yes. As shown in FIG. 8, these pins 63b ₁ are arranged at regular intervals so as not to come into contact with the ridges 63a ₁ of the upper extending roll 63a in the width direction of the roll. for the circumferential direction, are arranged substantially linearly at regular intervals along the outer peripheral surface 63 b _2. The stretching roll 63b downward in the present embodiment, as shown in FIG. 7, a plurality of pins 63b ₁ has a zigzag shape disposed configuration on the outer circumferential surface 63b ₂ of the lower draw roll 63b .

  When manufacturing the nonwoven fabric 1 for absorbent articles using the manufacturing apparatus 6 configured in this manner, preheating is applied to the fiber laminate 7 to be processed that is unwound from the unwinding apparatus 61. A preheating step and a shaping step of stretching the fiber laminate 7 that has undergone the preheating step to form an uneven shape are sequentially performed.

  In the preheating step, the fiber laminate 7 to be processed, which has been unwound from the unwinding device 61 and transported along the transporting direction MD, is applied to the pair of upper and lower heating rolls 62 a and 62 b rotating the preheating device 62. By making it contact with an outer peripheral surface, the said fiber laminated body 7 is heated and preheated. The preheating temperature in this preheating step can be appropriately set according to the type of the thermoplastic resin fibers constituting the fiber laminate 7. For example, the thermoplastic resin fibers are polyethylene terephthalate (PET) and high density polyethylene (HDPE). In the case of the core-sheath type composite fiber, the temperature of the outer peripheral surface of the heating roll is preferably about 60 to 120 ° C.

In the shaping step, the fiber laminate 7 that has been conveyed through the preheating step is inserted between a pair of upper and lower drawing rolls 63a and 63b that rotate while meshing in the shaping device 63, and the fiber laminate is obtained. 7, a protruding ridge 63a ₁ and recessed groove 63a ₂ of the upper stretch rolls 63a meshing and shaping extends between the pin 63 b ₁ of the lower draw roll 63 b. In addition, when implementing a shaping process, it is preferable to shape while heating a pair of upper and lower extending | stretching rolls 63a and 63b at 60-120 degreeC so that shaping may be performed easily.

In the shaping step, the upper drawing roll 63a is pushing a portion protruding ridge 63a ₁ is in contact with the fiber laminate 7 in the direction of stretching rolls 63b below, this protrusion 4 is shaped by . On the other hand, the stretching roll 63b downward, a plurality of pins 63b ₁ in the circumferential direction are arranged in a row, the fiber laminate 7 in contact with the tip portion of the pin 63b _1, corresponding upper drawing roll 63a pushed into the groove 63a _2. In this case, among the fiber laminate 7, a pin 63 b ₁ part tensioned in the groove 63a ₂ in a non-contact state is the first recess 51 of the groove 5. Further, since the portion that has been in contact with the tip portion of the pin 63b ₁ is strongly pressed into the concave groove 63a ₂ and shaped, the _second portion extends in the direction in which the convex portion 4 and the groove portion 5 are extended. so that the 1 peripheral wall 52a ₁ and the second peripheral wall portion 52a extending in the roll width direction _2, and a second recess 52 having a second bottom portion 52b is formed.

Note that the second bottom portion 52b of the second recess 52, at the time of its formation, in a state where the upper drawing roll 63a and the lower draw roll 63b is bitten a fiber laminate 7, the tip portion of the pin 63b ₁ fibers for slamming the contact portion of the stacked body 7 in the groove 63a _2, substantially fiber density is higher than the other portions of the nonwoven fabric. Thus, when the fiber density of the 2nd bottom part 52b arrange | positioned between the two adjacent convex parts 4 is relatively high, the fiber diameter contained in the above-mentioned 1st fiber layer 2 which comprises the said nonwoven fabric 1 is demonstrated. Since the thin thermoplastic resin fibers 2b are intertwined more closely with the cotton 2a contained in the first fiber layer 2 and the thermoplastic resin fibers 3a contained in the second fiber layer 3, in the second bottom portion 52b, the above-mentioned It is possible to make it difficult to cause the fiber layer splitting and delamination between the fiber layers as in the prior art. By providing a plurality of portions (that is, the second bottom portion) that are less likely to cause such fiber layer splitting or delamination between the fiber layers locally in the nonwoven fabric, the fiber layer splitting or Even if the delamination between the fiber layers partially occurs, the fiber layer is not split or delamination between the fiber layers does not occur at the second bottom, and it is possible to effectively prevent the strength of the nonwoven fabric from being lowered as a whole. it can.
In addition, the nonwoven fabric 1 has a structure in which a density gradient exists in the thickness direction _DT from the convex portion 4 having a relatively low fiber density to the second bottom portion 52b of the second concave portion 52 having the highest fiber density. Therefore, body fluids such as urine and menstrual blood supplied from the upper surface 1a (first surface) side of the nonwoven fabric 1 are transferred from the convex portion 4 on the upper surface 1a side of the nonwoven fabric 1 to the lower surface through the second bottom portion 52b. It is easy to be drawn to 1b (2nd surface) side, and can exhibit the absorptivity (especially absorption rate, liquid transferability, etc.) excellent as a nonwoven fabric for absorbent articles.

Then, the fiber laminate 7, the portion which was in contact with the both end portions in the width direction of the distal end portion of the pin 63b ₁ (the width direction of the roll), the protruding ridge 63a ₁ is a fiber layer 7 below the drawing rolls 63b The tension generated when pushing in the direction also acts so that the pin 63b ₁ scrapes the thermoplastic resin fiber forming the first peripheral wall portion 52a ₁ or breaks the fiber to form the broken fiber 54 having the broken end portion 54a. Or form. As a result, the hole 53 including the broken end portion 54 a of the broken fiber 54 is formed in the second recess 52. In addition, some thermoplastic resin fibers remain in a state of being spanned over the internal space 53b of the hole 53, and the broken end portion 54a of some of the broken fibers 54 extends into the internal space 53b. It becomes.
Here, the hole 53 is a direction along the conveyance direction MD of the fiber laminate 7 to be processed, that is, the rotation direction of the drawing rolls 63a and 63b, and the direction in which the convex part 4 and the groove part 5 are extended. It will be formed in the first peripheral wall portion 52a ₁ along.

  The fiber laminate in which the concavo-convex structure is shaped through the shaping step is formed with the above-described convex part 4 and the groove part 5 including the first concave part 51 and the second concave part 52, and the nonwoven fabric 1 for absorbent articles. Will be completed. The nonwoven fabric 1 for absorbent articles is then used for a surface sheet or leak-proof wall of absorbent articles such as disposable diapers and sanitary napkins.

Below, the nonwoven fabric for absorbent articles which concerns on another embodiment of this invention is demonstrated.
In another embodiment of the present invention, the nonwoven fabric for absorbent articles is a fiber laminate comprising three fiber layers, and the fiber laminate (nonwoven fabric) forms the first surface of the nonwoven fabric. A third fiber layer containing resin fibers and no cotton; the second fiber layer (intermediate layer) adjacent to the second surface side of the third fiber layer; and a second fiber layer second layer. It is comprised by the said 1st fiber layer containing the cotton adjacent to the surface of the surface side. When the nonwoven fabric for absorbent articles configured in this way is used as the top sheet of the absorbent article so that the first surface of the nonwoven fabric is the skin facing surface of the wearer, the skin facing surface of the topsheet is The second fiber layer is interposed as an intermediate layer between the third fiber layer to be formed and the first fiber layer containing cotton, and the third fiber layer and the first fiber layer are isolated, Since body fluids such as urine absorbed and retained in the cotton of one fiber layer are difficult to be transmitted to the third fiber layer and eventually the wearer's skin, the wearer perceives a wet state or feels stuffy. It is difficult to cause discomfort to the wearer.

Specific examples of the configuration of the three-layer fiber laminate in the other embodiment include the following configurations.
[First surface (skin facing surface) side fiber layer] (third fiber layer)
PET / PE core-sheath composite fiber [intermediate layer] (second fiber layer) having a fineness of 2.8 dtex, a fiber length of 45 mm, and a basis weight of 10 g / m ²
PET / PE core-sheath type composite fiber having a fineness of 2.8 dtex, a fiber length of 45 mm and a basis weight of 10 g / m ² [second surface (non-skin facing surface) side fiber layer] (first fiber layer)
PET / PE core-sheath type composite fiber with fineness of 2.2 dtex, fiber length of 44 mm and basis weight of 8 g / m ² , PET / PE core-sheath type composite fiber with fineness of 1,7 dtex, fiber length of 45 mm and basis weight of 1 g / m ² And a mixture of cotton having a basis weight of 1 g / m ²

  Moreover, in another embodiment of this invention, the nonwoven fabric for absorbent articles is a fiber laminated body which consists of three fiber layers, Comprising: A fiber laminated body (nonwoven fabric) forms the 1st surface of a nonwoven fabric. The second fiber layer, the first fiber layer (intermediate layer) containing cotton adjacent to the second surface side surface of the second fiber layer, and the second surface side surface of the first fiber layer It is comprised by the 3rd fiber layer which contains the thermoplastic resin fiber adjacent and does not contain cotton. The non-woven fabric for absorbent articles configured as described above is the first fiber containing cotton when used as a top sheet of the absorbent article so that the first surface of the non-woven fabric becomes the skin-facing surface of the wearer. Since the third fiber layer is interposed between the layer and the void portion on the second surface side (non-skin facing surface side) of the convex portion provided on the first surface of the nonwoven fabric, the third fiber Moisture generated by evaporation of body fluid such as urine, etc., released from the absorber disposed on the second surface side of the layer is absorbed and retained in the cotton of the first fiber layer, and the gap and the third It can be contained in the fiber layer (note that the void functions as a space for keeping moisture released from the absorber in a moisture state, and the third fiber layer is an auxiliary for containing moisture released from the absorber. It functions as a space.) As a result, the moisture released from the absorber can be effectively contained in the region on the second surface side of the first fiber layer, and the wearer can be made less likely to feel stuffiness.

Specific examples of the configuration of the three-layer fiber laminate in the other embodiment include the following configurations.
[First surface (skin facing surface) side fiber layer] (second fiber layer)
PET / PE core-sheath type composite fiber [intermediate layer] (first fiber layer) having a fineness of 2.8 dtex, a fiber length of 45 mm, and a basis weight of 10 g / m ²
PET / PE core-sheath type composite fiber with fineness of 2.2 dtex, fiber length of 44 mm and basis weight of 8 g / m ² , PET / PE core-sheath type composite fiber with fineness of 1,7 dtex, fiber length of 45 mm and basis weight of 1 g / m ² And a mixture of cotton having a basis weight of 1 g / m ² [second surface (non-skin facing surface) side fiber layer] (third fiber layer)
PET / PE core-sheath composite fiber having a fineness of 2.8 dtex, a fiber length of 45 mm and a basis weight of 10 g / m ²

  In each of the above-described embodiments, the thermoplastic resin fiber included in the third fiber layer is not particularly limited, and the same thermoplastic resin fiber as included in the first fiber layer or the second fiber layer is used. be able to. Furthermore, in these embodiments, each fiber layer has the same basis weight of the thermoplastic resin fibers, and the thermoplastic resin fibers contained in the second fiber layer and the third fiber layer are the first fibers, respectively. It is preferable to have a larger fiber diameter (fineness) than the thermoplastic resin fibers contained in the layer. When the nonwoven fabric (fiber laminate) has such a configuration, the amount of fibers (number of fibers) of the thermoplastic resin fibers contained in the first fiber layer inevitably is the second fiber layer and the third fiber layer. Since it becomes larger than the fiber layer, the strength of the first fiber layer containing cotton can be further improved. Further, in such a nonwoven fabric, the thermoplastic resin fibers of the first fiber layer are easily entangled with the thermoplastic resin fibers of the second fiber layer or the third fiber layer, so that the fiber layer constituting the nonwoven fabric contains cotton. Even in such a case, delamination between the fiber layers hardly occurs.

In the absorbent article for nonwoven fabric 1 according to an embodiment of the present invention, the hole 53 of the second recess 52, a pair of which is formed along the first direction D ₁ first wall portion 52a ₁ Although provided in the absorbent article for nonwoven fabric of the present invention is not limited to such embodiments, for example, holes are provided on one of the peripheral wall portion of the pair of first wall section 52a ₁ it is also be, may be provided on the second peripheral wall portion of the pair that is formed along the second direction D _2, or may be provided in one of the peripheral wall either.
Furthermore, in the nonwoven fabric 1 for absorbent articles according to the embodiment, the hole 53 is provided at a position near the second bottom 52b in the peripheral wall 52a of the second recess 52, but the absorbent article of the present invention. In the nonwoven fabric for use, it is not limited to such an embodiment, and the hole can be provided at any position as long as the flexibility of the nonwoven fabric is not impaired.

  Moreover, in the nonwoven fabric 1 for absorbent articles which concerns on the said embodiment, although the one part fiber 55 of the thermoplastic resin fibers was spanned in the internal space 53b of the said hole 53, of this invention In the nonwoven fabric for absorbent articles, the fibers spanned in the internal space of such a hole may not exist. Further, in the present invention, as in the above embodiment, the broken end portion of the broken fiber does not have to extend into the internal space of the hole.

In the nonwoven fabric 1 for absorbent articles according to the embodiment, the second recess 52 is formed in a substantially rectangular parallelepiped shape. However, in the nonwoven fabric for absorbent article of the present invention, the shape of the second recess is particularly limited. It can be made into arbitrary shapes, such as column shape and prismatic shape.
Further, in the above embodiment, the convex portion 4 extends continuously in the first direction D ₁ of the said non-woven fabric 1, in the absorbent article for non-woven fabric of the present invention, the convex portion is not necessarily the first nonwoven It does not need to extend continuously in the direction, and may be intermittent. However, about the 2nd crevice, it is preferred to provide in the 1st bottom part of the 1st crevice pinched between the parts where a convex part continues, and this makes it easy to touch a wearer's skin first. In addition, since the skin of the wearer is less likely to come into contact with the second recess, it is possible to make it less likely to cause a sense of discomfort or a foreign object due to touching the second recess.

  The nonwoven fabric for absorbent articles of the present invention is not limited to the above-described embodiments and the like, and can be appropriately combined and changed within a range not departing from the purpose and spirit of the present invention. In this specification, ordinal numbers such as “first” and “second” are used to distinguish items with the ordinal numbers, and mean the order, priority, importance, etc. of each item. Not what you want.

DESCRIPTION OF SYMBOLS 1 Nonwoven fabric for absorbent articles 2 First fiber layer 2a Cotton 2b Thermoplastic resin fiber 3 Second fiber layer 3a Thermoplastic resin fiber 4 Convex part 41 Top part 5 Groove part 51 First concave part 51a First bottom part 52 Second concave part 52a Peripheral wall part 52b 2nd bottom part 53 Hole part 6 Manufacturing apparatus 61 Unwinding apparatus 62 Preheating apparatus 63 Shaping apparatus

Claims (5)

Fibers of at least two layers including a first fiber layer containing cotton and thermoplastic resin fibers, and a second fiber layer containing thermoplastic resin fibers and not containing cotton adjacent to at least one surface of the first fiber layer. A non-woven fabric for absorbent articles comprising layers,
The thermoplastic resin fiber contained in the first fiber layer has a fiber diameter smaller than that of the thermoplastic resin fiber contained in the second fiber layer,
The non-woven fabric has a first surface and a second surface opposite to the first surface, and extends in a first direction on the first surface of the non-woven fabric and is orthogonal to the first direction. Between a plurality of convex portions that are provided in two directions at a predetermined interval and project in the direction of the first surface, and the convex portions that extend in the first direction and are adjacent in the second direction. Provided with a plurality of grooves recessed in the direction of the second surface,
The groove includes a first recess having a first bottom located on the second surface side relative to a position on the first surface at the top of the convex portion, and is not in the first direction in the first recess. A plurality of second recesses recessed continuously from the first bottom toward the second surface;
The second recess is provided so as to close the end portion of the peripheral wall portion extending from the first bottom portion toward the second surface side and the end portion of the peripheral wall portion on the second surface side. A second bottom portion having the highest fiber density among the nonwoven fabrics,
The nonwoven fabric.   The peripheral wall portion has a pair of first peripheral wall portions along the first direction and a pair of second peripheral wall portions along the second direction, and at least one of the pair of first peripheral wall portions, The nonwoven fabric according to claim 1, comprising a hole that communicates with the second surface.   The nonwoven fabric according to claim 1 or 2, wherein the first surface of the nonwoven fabric is formed by a fiber layer other than the first fiber layer.   The nonwoven fabric as described in any one of Claims 1-3 whose pitch in the said 2nd direction of the said 2nd recessed part is 1.5 mm or less.   The non-woven fabric includes the first fiber layer forming the second surface, the second fiber layer adjacent to the first surface side of the first fiber layer, and the first surface side of the second fiber layer. And the third fiber layer containing thermoplastic resin fibers and not containing cotton, each fiber layer having the same basis weight of the thermoplastic resin fibers, and the third fiber layer The nonwoven fabric according to any one of claims 1 to 4, wherein the thermoplastic resin fiber contained in the fiber has a fiber diameter equal to or greater than that of the thermoplastic resin fiber contained in the second fiber layer.

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