TWI675138B - Non-woven fabric for absorbent articles - Google Patents

Abstract

An object of the present invention is to provide a non-woven fabric for absorbent articles, which is a non-woven fabric for absorbent articles that includes a fiber layer composed of thermoplastic resin fibers and a fiber layer composed of thermoplastic resin fibers and cotton, and has strength and flexibility. Excellent in liquid permeability to body fluids such as urine and menstrual blood.

The nonwoven fabric (1) for an absorbent article of the present invention is composed of at least two fiber layers including a first fiber layer (2) and a second fiber layer (3), and the first fiber layer (2) contains cotton (2a ) And thermoplastic resin fibers (2b), the second fiber layer (3) is adjacent to at least one side of the first fiber layer (2), contains thermoplastic resin fibers (3a) and does not contain cotton; the first fiber layer ( 2) The fiber diameter of the thermoplastic resin fiber (2b) contained is smaller than the fiber diameter of the thermoplastic resin fiber (3a) contained in the second fiber layer (3), and the nonwoven fabric (1) is provided with a plurality of The convex portion (4) and the groove portion (5) have a specific structure.

Description

Non-woven fabrics for absorbent articles

The present invention relates to non-woven fabrics for absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads.

Absorbent articles such as disposable diapers, sanitary napkins, etc. In order to obtain the peace of mind provided by natural materials, etc., non-woven fabrics containing cotton (natural fiber) are being investigated as non-woven fabrics used as members for surface sheets and the like.

As such a non-woven fabric, for example, Patent Document 1 proposes a short-fiber non-woven fabric which is formed by a layer composed of short fibers such as thermoplastic resin fibers in at least a single-area layer of a layer mainly composed of cotton with a fiber length of 5 mm. The fibers, the cotton fleece, and the cotton fleece and the short fiber are entangled with each other in three dimensions to become integrated.

[Patent Document 1] Japanese Patent Laid-Open No. 2001-32157

However, like the nonwoven fabric disclosed in Patent Document 1, a laminated nonwoven fabric including a fibrous layer composed of short fibers such as thermoplastic resin fibers and a fibrous layer composed of short fibers such as thermoplastic resin fibers and cotton is caused by short fibers. Differences in the chemical properties of fibers and cotton (for example, hydrophobicity, hydrophilicity, etc.), differences in physical properties (for example, different rigidity, etc.), the entanglement between short fibers and cotton is weak, and short fibers and cotton are easily dissociated. When such a laminated nonwoven fabric is applied to an article accompanied by a structural change (deformation), such as an absorbent article, the short-fiber and cotton may be dissociated in the fiber layer containing cotton due to the structural change (deformation) of the product, which may induce the The fibrous layer is split (decomposed) and peeled off from the adjacent fibrous layer, resulting in a decrease in the strength of the laminated nonwoven fabric. Especially when the laminated nonwoven fabric is applied to an absorbent article, if the fibrous layer constituting the laminated nonwoven fabric is split (decomposed), interlayer peeling occurs, fluff may occur, or body fluids such as urine and menstrual blood supplied to the absorbent article may be generated. Poor transferability.

In addition, because the rigidity of cotton fibers is high, if the amount of cotton contained in the fiber layer increases, the softness of the fiber layer will decrease, and the cushioning, touch, and followability to the body shape of the laminated nonwoven fabric containing the fiber layer will be reduced. May be reduced.

Therefore, an object of the present invention is to provide a nonwoven fabric for absorbent articles, comprising a fibrous layer composed of thermoplastic resin fibers and a fibrous layer composed of thermoplastic resin fibers and cotton. It is excellent in flexibility, and has excellent liquid permeability to body fluids such as urine and menstrual blood.

A non-woven fabric for an absorbent article according to one aspect (Aspect 1) of the present invention is a non-woven fabric for an absorbent article composed of at least two fiber layers including a first fiber layer and a second fiber layer, and the first fiber The layer contains cotton and thermoplastic resin fibers; the second fiber layer is adjacent to at least one side of the first fiber layer, contains thermoplastic resin fibers and does not contain cotton; and the fibers of the thermoplastic resin fibers contained in the first fiber layer The diameter is smaller than the fiber diameter of the thermoplastic resin fiber contained in the second fiber layer; the nonwoven fabric has a first surface and a second surface, and the first surface is formed of a fiber layer other than the first fiber layer The second surface is formed by the first fiber layer and is located on the side opposite to the first surface; the non-woven fabric has a plurality of convex portions and a plurality of groove portions, and the plurality of convex portions are connected to the non-woven fabric. The first surface extends toward the first direction and is provided at a predetermined interval in the second direction orthogonal to the first direction, and protrudes toward the first surface. The plurality of groove portions are directed toward the first surface. The first direction is extended The groove is provided between the convex portions adjacent in the second direction and is recessed toward the second surface; the groove portion includes a first concave portion and a plurality of second concave portions, and the first concave portion includes a first concave portion. Bottom, the first bottom is located on the second surface side than the first surface side of the top of the convex portion; the plurality of second concave portions are discontinuous in the first direction within the first concave portion; The second recessed portion includes a peripheral wall portion and a second bottom portion, and the peripheral wall portion extends from the first bottom portion toward the second surface side; The second bottom portion is on the second surface side of the peripheral wall portion. The end portion is provided to close the end portion and has the highest fiber density among the aforementioned non-woven fabrics.

According to the aspect 1 of the nonwoven fabric for absorbent articles, the fiber diameter of the thermoplastic resin fibers contained in the first fiber layer is thinner than the fiber diameter of the thermoplastic resin fibers contained in the second fiber layer. The thermoplastic resin fibers containing a relatively small fiber diameter are easily entangled with the cotton contained in the first fiber layer and the thermoplastic resin fibers contained in the second fiber layer, thereby suppressing the above-mentioned fibrous layer splitting and inter-fiber layers. Interlayer peeling occurs, and even if the nonwoven fabric contains cotton as a constituent, it can still exhibit its excellent strength as a nonwoven fabric.

In addition, the non-woven fabric for absorbent article of aspect 1 has the above-mentioned specific convex portion and groove portion structure, that is, the groove portion has a first concave portion and a second concave portion, and the first concave portion is provided with a first concave portion and a second concave portion. 1 bottom, the 1st bottom is located on the 2nd surface side from the 1st surface side of the top of the said convex part; the 2nd recessed part is provided with the peripheral wall part and the 2nd bottom part, and this peripheral wall part is from the said 1st bottom part The second bottom portion is provided to extend toward the second surface side. The end portion of the second bottom portion on the second surface side of the peripheral wall portion is provided to close the end portion and has the highest fiber density among the nonwoven fabrics. The fiber density of the first recessed portion and the first recessed portion is relatively low. In addition, the stress in the thickness direction applied from the first surface side of the nonwoven fabric can be cushioned by bending the first recessed portion toward the second surface side. Nonwoven fabrics made of cotton as a component can still ensure sufficient softness.

Furthermore, the density of the fibers at the second bottom portion disposed between the convex portions is relatively high, so that the diameter of the fibers contained in the first fiber layer is relatively small. The flexible resin fibers can be entangled more tightly with the cotton contained in the first fiber layer and the thermoplastic resin fibers contained in the second fiber layer. Therefore, in the second bottom portion, it is less likely that the above-mentioned fiber layer will occur. Split and peel between layers of each fiber. In the non-woven fabric, a plurality of such portions that are less prone to fibrous layer splitting and interlayer peeling between the fiber layers (that is, the second bottom portion) are locally provided. Interlayer peeling between layers occurs locally, and fibrous layer splitting and interlayer peeling between the fiber layers do not occur in the second bottom portion, which can effectively prevent a decrease in the strength of the entire nonwoven fabric.

In addition, the structure of the non-woven fabric for the absorbent article of aspect 1 has a density gradient in the thickness direction 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. The bodily fluids such as urine and menstrual blood supplied on the first surface side can be easily introduced from the convex portion on the first surface side of the non-woven fabric to the second surface side through the second bottom, and can exhibit excellent absorbency as a non-woven fabric for absorbent articles In particular, absorption rate, liquid transferability, etc.).

The non-woven fabric for an absorbent article according to another aspect (Aspect 2) of the present invention is the non-woven fabric for an absorbent article according to the aspect 1, wherein the peripheral wall portion includes a first pair of first pairs along the first direction. The peripheral wall portion and the second peripheral wall portion along one of the pair of the second directions include at least one of the first peripheral wall portions of the pair: a hole portion leading to the second surface.

According to the non-woven fabric for an absorbent article according to the aspect 2, the holes of the first peripheral wall portion can release the tension of the fibers forming adjacent convex portions, so the entire convex portion or the fibers forming the convex portion can move. from As the degree of freedom is improved, the flexibility of the convex portion is further improved.

The non-woven fabric for an absorbent article according to another aspect (Aspect 3) of the present invention is the nonwoven fabric for an absorbent article according to the aspect 1 or 2, wherein the first surface of the non-woven fabric is made of fibers other than the first fiber layer. Layer formed.

The non-woven fabric for an absorbent article according to this aspect 3, and the first surface of the non-woven fabric used as the skin abutment surface of the wearer of the absorbent article are formed of a fiber layer other than the first fiber layer containing cotton. It can prevent deterioration of touch and softness caused by cotton, and can maintain excellent touch and softness as a non-woven fabric.

The non-woven fabric for an absorbent article according to another aspect (Aspect 4) of the present invention is the non-woven fabric for an absorbent article according to any of Aspects 1 to 3, wherein the pitch of the second recessed portion in the second direction is 1.5 mm. the following.

According to the non-woven fabric for absorbent articles according to aspect 4, since the pitch of the second recessed portion in the second direction is 1.5 mm or less, the cotton in the first fiber layer is easily held at the second portion of the second recessed portion. In the bottom part, the above-mentioned second bottom part is less likely to cause the fibrous layer to split as described above, and interlayer peeling between the respective fibrous layers. Therefore, a nonwoven fabric having particularly excellent strength and liquid permeability can be obtained.

The non-woven fabric for an absorbent article according to another aspect (Aspect 5) of the present invention is the non-woven fabric for an absorbent article according to any of Aspects 1 to 4, wherein the non-woven fabric includes the first fiber forming the second surface. Layer, the second fiber layer adjacent to the surface on the first surface side of the first fiber layer, and the third fiber layer adjacent to the surface on the first surface side of the second fiber layer, the The third fiber layer contains thermoplastic resin fibers and does not contain cotton; the basis weight of the thermoplastic resin fibers in each fiber layer is the same. The fiber diameter of the thermoplastic resin fibers contained in the third fiber layer is the same as that of the second fiber layer. The thermoplastic resin fibers have the same or larger fiber diameter.

Generally speaking, when the fiber of the cotton material is dissociated, it is easy to retain the cotton pieces that cannot be completely dissociated. Such cotton pieces become the cause of the entanglement with the surrounding fibers to loosen. As a result, the fiber layer may be caused. The strength decreases. However, the nonwoven fabric for the absorbent article according to the aspect 5 is configured such that the basis weight of the thermoplastic resin fibers in each fiber layer is the same, and the fiber diameters of the thermoplastic resin fibers included in the second fiber layer and the third fiber layer, It is larger than the thermoplastic resin fibers contained in the first fiber layer, so the thermoplastic resin fibers contained in the first fiber layer have more fibers (the number of fibers) than the second fiber layer and the third fiber layer, On the other hand, the strength of the first fiber layer containing cotton can be improved. In addition, in the structure of the non-woven fabric for absorbent article of aspect 5, the fiber amount (the number of fibers) exists from the first surface to the second surface (that is, from the third fiber layer to the first fiber layer) in the thickness direction. ) Increases the fiber amount gradient (or there is a fiber density gradient with an increased fiber density from the first surface to the second surface (from the third fiber layer to the first fiber layer)), so it is supplied to the first nonwoven fabric. The bodily fluids such as urine and menstrual blood on one surface side can be easily introduced from the first surface side to the second surface side of the non-woven fabric, and can exhibit superior absorbency (especially absorption speed, liquid, etc.) as a non-woven fabric for absorbent articles. Transferability, etc.).

According to the present invention, there is provided a nonwoven fabric for absorbent articles, comprising a fibrous layer composed of thermoplastic resin fibers and a nonwoven fabric for absorbent articles including a fibrous layer composed of thermoplastic resin fibers and cotton, and has strength and flexibility. Excellent in liquid permeability to body fluids such as urine and menstrual blood.

1‧‧‧ Non-woven fabric for absorbent articles

2‧‧‧ the first fiber layer

2a‧‧‧cotton

2b‧‧‧thermoplastic resin fiber

3‧‧‧ 2nd fiber layer

3a‧‧‧Thermoplastic resin fiber

4‧‧‧ convex

41‧‧‧Top

5‧‧‧Groove section

51‧‧‧1st recess

51a‧‧‧1st bottom

52‧‧‧ 2nd recess

52a‧‧‧Zhoubi

52b‧‧‧ 2nd bottom

53‧‧‧ Hole

6‧‧‧Manufacturing equipment

61‧‧‧Unwinding device

62‧‧‧Preheating device

63‧‧‧Shaping device

FIG. 1 is a perspective view of a nonwoven fabric for an absorbent article according to an embodiment of the present invention.

Fig. 2 is a plan view of a nonwoven fabric for an absorbent article according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a non-woven fabric for an absorbent article according to an embodiment of the present invention, taken along a line III-III ′ shown in FIG. 2.

4 (a) is an enlarged cross-sectional view of a non-woven fabric for an absorbent article according to an embodiment of the present invention, taken along the line IV-IV 'shown in FIG. 2, and FIG. 4 (b) is a sectional view of FIG. 4 (a). The enlarged schematic view of the main part of the cross section of the nonwoven fabric for absorbent articles shown.

Fig. 5 is a schematic diagram for explaining an example of a manufacturing apparatus for a nonwoven fabric for an absorbent article of the present invention.

FIG. 6 is an enlarged perspective view schematically showing a main part of a pair of forming rollers of a forming device provided in the nonwoven fabric manufacturing apparatus for an absorbent article of the present invention.

Fig. 7 shows the lower side of the pair of forming rollers shown in Fig. 6 An enlarged schematic view of the main part of the pin configuration of the roller.

FIG. 8 is an enlarged schematic view showing a main part of the meshing state of the upper forming roller and the lower forming roller in the pair of forming rollers shown in FIG. 6.

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

1 to 4 are schematic diagrams of a nonwoven fabric 1 for an absorbent article according to an embodiment of the present invention. In this specification, unless otherwise specified, the unwoven fabric in the expanded state is simply referred to as "top view" when viewed from the upper surface side in the thickness direction D _T.

As shown in FIGS. 1 to 4, the nonwoven fabric 1 for an absorbent article according to the first embodiment of the present invention includes a first surface as an upper surface 1 a and a second surface opposite to the upper surface 1 a as a second surface. The lower surface 1b is composed of two layers of fiber laminates including the first fiber layer 2 and the second fiber layer 3. The first fiber layer 2 is a fiber layer forming the lower surface 1b and contains cotton 2a and a thermoplastic resin. Fiber 2b; The second fiber layer 3 is a fiber layer adjacent to the surface on the upper surface 1a side of the first fiber layer 2 and forming the upper surface 1a, and contains thermoplastic resin fibers 3a and does not contain cotton. Furthermore, after the nonwoven has a specific uneven structure described later, i.e., a system having a plurality of convex portions and a plurality of groove portions 4 5, a plurality of convex portions 1a towards the surface 4 based on the first direction D ₁ extends The second direction D ₂ orthogonal to the first direction D ₁ is provided at a predetermined interval and protrudes toward the upper surface 1 a. The plurality of groove portions 5 extend toward the first direction D _1. And disposed between the convex portions 4 adjacent in the second direction D ₂ and recessed toward the lower surface 1 b; the groove portion 5 includes a first concave portion 51 and a plurality of second concave portions 52, The first recessed portion 51 includes a first bottom portion 51a, and the first bottom portion 51a is located closer to the second surface 1b than the position of the first surface 1a side of the top portion 41 of the convex portion 4; The first recessed portion 51 is discontinuously provided in the first direction D ₁ and is recessed from the first bottom portion 51 a toward the second surface 1 b. Further, the second recessed portion 52 includes a peripheral wall portion 52 a and a first portion. The bottom portion 52b and the peripheral wall portion 52a extend from the first bottom portion 51a toward the second surface 1b side, and the second bottom portion 52b is an end portion on the second surface 1b side of the peripheral wall portion 52a so as to close the end portion, and has the highest fiber density in the nonwoven fabric 1.

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 types of absorbent articles such as adhesive-type or pants-type disposable diapers, sanitary napkins, and pads. . The non-woven fabric for an absorbent article of the present invention can be used as, for example, a sheet laminated on the outer surface of a back sheet such as a disposable diaper, but is preferably used as a disposable sheet. Sheets of absorbent articles such as diapers, sanitary napkins, and leak-proof walls, which may come into contact with the skin of the wearer.

When the nonwoven fabric for absorbent articles of the present invention is applied to a surface sheet or the like of an absorbent article, it is based on the sense of touch and softness. The point is preferably arranged so that the first surface provided with the convex portion faces the skin of the wearer.

The fiber laminate of the nonwoven fabric 1 for absorbent articles which constitutes one embodiment of the present invention is composed of two fiber laminates including a first fiber layer 2 and a second fiber layer 3, and the first fiber layer 2 contains cotton 2a and the thermoplastic resin fiber 2b, the second fiber layer 3 is a fiber layer adjacent to the surface on the upper surface 1a side of the first fiber layer 2 and forming the upper surface 1a, and contains the thermoplastic resin fiber 3a and does not contain cotton. However, the fiber laminate of the present invention 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, and 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 can be used. Among them, for cotton having a fiber length of 20 mm or more, when a first fiber layer is laminated with a second fiber described later (that is, when a fiber laminate is formed), a part of the cotton fibers easily enters into the second fiber layer, so that Non-woven fabrics are preferred because they have improved liquid permeability. In addition, cotton blended from cotton with a fiber length of 20 mm or more and cotton with a fiber length of 10 mm or less can use cotton with a fiber length of 20 mm or more to increase the liquid permeability of the nonwoven fabric, and use cotton with a fiber length of 10 mm or less to increase the nonwoven fabric The volume is therefore particularly good.

The cotton content of the first fiber layer is not particularly limited. From the viewpoints of water absorption, water retention, flexibility, etc., for example, it is in the range of 1 to 70% by mass, and preferably in the range of 2 to 30% by mass.

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 composed of a thermoplastic resin. Examples of the thermoplastic resin include polyethylene (PE) and polypropylene. (PP), ethylene-vinyl acetate copolymer (EVA), olefin resins, polyester resins such as polyethylene terephthalate (PET), polylactic acid (PLA), etc. Known resins, such as amine resins, may be used alone, or two or more resins may be used in combination.

In addition, the structure of the fibers made of such a thermoplastic resin is not particularly limited, and examples include composite fibers such as core-sheath fibers, side-by-side fibers, island / sea fibers, hollow fibers, flat and Y-shaped fibers. Shaped cross-section fibers such as C, C, etc., three-dimensionally crimped fibers that are potentially crimped or appear crimped, and split fibers that are split using physical loads such as water flow, heat, and embossing. Fibers with these structures can be used. They can be used alone or in combination of two or more kinds of fibers.

The fineness (fiber diameter) of the thermoplastic resin fiber is not particularly limited as long as it is smaller than the fiber diameter of the thermoplastic resin fiber contained in the second fiber layer described later, and is based on the strength and softness of the nonwoven fabric, touch, and liquid. From the viewpoint of transparency, 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.

In addition, the fiber length of the thermoplastic resin fiber is not particularly limited. From the viewpoint of strength, flexibility, and liquid permeability of the non-woven fabric, it is usually within a range of 20 to 100 mm, and preferably within a range of 35 to 65 mm. The thermoplastic resin fiber may be subjected to a hydrophilization treatment as Such hydrophilization treatments include, for example, treatments using a surfactant, a hydrophilic agent, and the like (for example, blending a surfactant into the fiber and applying a surfactant to the fiber surface).

The content of the thermoplastic resin fibers in the first fiber layer is not particularly limited. From the viewpoint of the strength and flexibility of the non-woven fabric, for example, it is in the range of 30 to 99% by mass, and preferably in the range of 70 to 98% by mass. .

The first fiber layer may contain fibers other than the cotton and thermoplastic fibers, optional additives, and the like, as long as the effects of the present invention are not hindered.

Next, the second fiber layer constituting the nonwoven fabric for an absorbent article of the present invention will be described. The thermoplastic resin fibers contained in the second fiber layer are not particularly limited except that the thermoplastic resin fibers have a thicker fiber diameter than the thermoplastic resin fibers contained in the first fiber layer. Any thermoplastic resin fibers can be used. From the viewpoint of entanglement easiness and the like, it is preferable to adopt the same fibers (that is, the same as those contained in the first fiber layer) except for the fiber diameter (fineness) of the thermoplastic resin fibers contained in the first fiber layer. Thermoplastic resin fibers are made of the same material (resin) and have the same fiber length).

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 fibers contained in the first fiber layer have a fiber diameter smaller than that of the thermoplastic resin fibers contained in the second fiber layer, the fiber diameter contained in the first fiber layer The thinner thermoplastic resin fibers are easily entangled with the cotton contained in the first fiber layer and the thermoplastic resin fibers contained in the second fiber layer, and it is not easy for the above-mentioned fibrous layer to split and the layers between the fiber layers to occur easily. Even if the nonwoven fabric contains cotton as a constituent component, it can maintain excellent strength as a nonwoven fabric.

In the present invention, the fiber laminated body constituting the non-woven fabric for absorbent articles is not limited to the two-layer laminated body of the above embodiment, and may be composed of three or more fiber layers according to desired absorbency, flexibility, and the like. Laminated body. In addition, in the nonwoven fabric for an absorbent article of the present invention, the first surface of the nonwoven fabric is preferably formed of a fiber layer other than the first fiber layer containing cotton, regardless of the number of layers of the fiber laminate. The first surface of the absorbent article, which is the skin abutment surface of the wearer, is formed of a fiber layer other than the first fiber layer containing cotton, which can prevent deterioration of touch and softness caused by cotton, and can Maintains excellent touch and softness as a non-woven fabric.

In the nonwoven fabric for an absorbent article of the present invention, the fiber layers other than the first fiber layer and the second fiber layer are not particularly limited, and examples thereof include natural fibers such as wool and regenerated fibers such as rayon. Fiber layer composed of synthetic resin fibers such as inorganic fibers, thermoplastic resin fibers, and the like. Still other fiber layers may contain arbitrary additives and the like within a range that does not inhibit the effects of the present invention.

In the present invention, the basis weight of each fiber layer constituting the non-woven fabric for absorbent articles is not particularly limited. From the viewpoints of the strength, softness, and absorbency of the non-woven fabric, the ranges are, for example, 1 to 60 g / m ² . , Preferably in the range of 10 to 30 g / m ² . The basis weight of the non-woven fabric for absorbent articles is not particularly limited, but 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 in the range of 20 to 50 g / m ² . Inside.

In addition, the thickness of the non-woven 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, and more preferably in the range of 0.8 to 2 mm.

In the nonwoven fabric for an absorbent article according to another embodiment of the present invention, the nonwoven fabric includes the first fiber layer forming the second surface of the nonwoven fabric, and the surface adjacent to the first surface side of the first fiber layer. The second fiber layer and the third fiber layer adjacent to the surface on the first side of the second fiber layer, the third fiber layer contains thermoplastic resin fibers and does not contain cotton; the thermoplastic resin fibers of each fiber layer have the same basis weight The fiber diameter (fineness) of the thermoplastic resin fibers contained in the third fiber layer is the same as or larger than the thermoplastic resin fibers contained in the second fiber layer.

In the nonwoven fabric for absorbent articles of this embodiment, the amount of fibers (the 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, so that the cotton content can be further increased. The strength of the first fiber layer. In addition, in the structure of such a non-woven fabric, the fiber amount (the number of fibers) increases from the first surface to the second surface (that is, from the third fiber layer to the first fiber layer) of the non-woven fabric in the thickness direction. Fiber density gradient (or a fiber density gradient with an increase in fiber density from the first surface to the second surface (from the third fiber layer to the first fiber layer)) is supplied to the first surface side of the nonwoven fabric Body fluids such as urine, menstrual blood, The non-woven fabric can be easily introduced from the first surface side to the second surface side, and can exhibit superior absorption properties (in particular, absorption speed, liquid transfer properties, etc.) as a nonwoven fabric for absorbent articles.

Next, the manufacturing method of the fiber laminated body before the uneven | corrugated shaping | molding process (before the uneven structure formation) which comprises the nonwoven fabric for absorbent articles of this invention is demonstrated.

In the present invention, the means for producing the fiber laminate is not particularly limited, and examples thereof include using fibers for forming the respective fiber layers (that is, cotton and thermoplastic resin fibers for forming the first fiber layer, A method of forming a second fiber layer of thermoplastic resin fibers, etc.), and respectively forming a fiber network (fleece) corresponding to each fiber layer, and a method of physically or chemically bonding fibers in each fiber network and between the fiber networks.

Specifically, a fiber laminate including the two layers of the first fiber layer and the second fiber layer can be produced in the following procedure.

(1) A manufacturing device is provided, which includes a conveying device that conveys a sheet-like member in one direction, a first-stage cutting device that is disposed above the conveying device and is disposed on an upstream side in the conveying direction, and the conveying device A second-stage cutting device disposed above the device and positioned downstream of the conveying direction (that is, further downstream than the first-stage cutting device), and a heating device of a hot-air type disposed on the downstream side of the second-stage cutting device. .

(2) The thermoplastic resin fiber for forming the second fiber layer is supplied to the first-stage cutting device, and the thermoplastic resin fiber is opened by a pin of a rotating roller in the cutting device, thereby corresponding to the second section. The fiber web of the fiber layer is formed on the carrying surface of the carrying device.

(3) Supply the cotton and thermoplastic resin fibers used to form the first fiber layer while conveying the fiber web corresponding to the second fiber layer formed on the conveying surface of the conveying device to the downstream side in the conveying direction. For the aforementioned second stage cutting device, each fiber is opened by a pin of a rotating roller in the aforementioned cutting device, so that a fiber web corresponding to the first fiber layer is formed during transportation and corresponds to the second fiber layer. Fiber online.

(4) The laminated fibrous web formed by laminating the fibrous web corresponding to the first fibrous layer on the fibrous web corresponding to the second fibrous layer is transferred to the heating device of the hot air method, and in the heating device, the The fibers in and between the fiber webs are entangled with each other, and the thermoplastic resin fibers are arbitrarily thermally fused with each other, and cotton is fused and fixed to the surface of the thermoplastic resin fibers, thereby producing the first fiber layer and the second A two-layer fiber laminate composed of fiber layers.

When a fiber laminate including three or more fiber layers is manufactured, a manufacturing device in which the cutting device is arranged in three or more stages can be used, and the manufacturing can be performed in the same manner as described above.

The method for forming a fiber web corresponding to each fiber layer is not limited to the above method, and for example, a wet method or the like can be used. In addition, the method of bonding the fiber web is not limited to the above method, and for example, a water entanglement method, a needle punch method, or the like can also be used.

The fiber laminate produced in this manner is provided with the above-mentioned specific uneven structure by an uneven-shape forming process described later to obtain a nonwoven fabric for an absorbent article of the present invention.

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

As shown in FIGS. 1 to 4, the nonwoven fabric 1 for an absorbent article according to an embodiment of the present invention is configured as a region of the first surface 1 a and a region of the second surface 1 b of the convex portion 4 from the second surface 1 b. The direction in which the side faces the first surface 1a side is convexly curved. On the other hand, the first recessed portion 51 of the groove portion 5 is a region of the first surface 1a and a region of the second surface 1b of the first recessed portion 51, and is configured to go from the first surface 1a side to the second surface 1b. The side direction is convexly curved. Therefore, with respect to the second direction D ₂ orthogonal to the first direction D ₁ extending from the convex portion 4, the nonwoven fabric 1 has a sheet shape with a substantially wavy cross section in which the irregularities alternate.

The convex portion 4 extends toward the first direction D ₁ (for example, the lengthwise direction of the nonwoven fabric) of the surface (sheet surface) of the nonwoven fabric 1 and is orthogonal to the first direction D ₁ of the surface of the nonwoven fabric 1. In the second direction D ₂ (for example, the width direction of the nonwoven fabric), a plurality of rows are arranged at predetermined intervals. In the present embodiment, each of the convex portions 4 is continuously extended in the first direction D ₁ and parallel to the other convex portions 4.

In the nonwoven fabric for an absorbent article of the present invention, the interval between the convex portion and other adjacent convex portions is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and particularly preferably 0.75 to 2 mm. Here, the "interval between adjacent convex portions" means the distance between the substantially central positions (substantially the tops of the convex portions) in the second direction D ₂ of each convex portion.

When the distance between adjacent convex parts is less than 0.25 mm, the uneven structure of the nonwoven fabric is too fine, and the contact area between the convex parts of the nonwoven fabric and the wearer's skin cannot be sufficiently reduced. Therefore, the surface of the nonwoven fabric (the first surface) The touch may be reduced. On the other hand, when the distance between adjacent convex portions exceeds 5 mm, the difference in structure from the non-woven fabric (that is, the fiber laminate) before the concave-convex forming process becomes small, making it difficult to obtain Soft feel with uneven structure.

Further, in the nonwoven fabric for an absorbent article of the present invention, regarding the convex portion, the length from the height of 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) It is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and particularly preferably 0.75 to 2 mm. When the height of the convex portion is less than 0.25 mm, the protrusion of the convex portion is too small, and it is difficult to obtain a soft touch using the uneven structure. On the other hand, when the height of the convex portion exceeds 5 mm, the protrusion of the convex portion is too large and becomes sharp. The structure makes it difficult to obtain a soft touch.

As shown in FIGS. 1 to 4, in the nonwoven fabric 1 for an absorbent article according to an embodiment of the present invention, the groove portion 5 is provided in a space between adjacent convex portions 4 and 4 in the second direction D ₂ . toward the first direction D ₁ extends, the groove portion 5 system having a first concave portion 51 and a plurality of second recessed portions 52, a first recess 51 includes a bottom of a first 51a, a bottom of the first 51a based positioned than the top of the convex portion 41 of The position on the side of the first surface 1a is closer to the direction of the second surface 1b; the plurality of second recessed portions 52 are discontinuously provided in the first recessed portion 51 along the first direction D ₁ and face from the first bottom portion 51a. The second surface 1b is recessed in the direction.

The nonwoven fabric for an absorbent article of the present invention has a structure having such specific convex portions and groove portions, that is, the groove portions have a first concave portion and a second concave portion, and the first concave portion includes a first bottom portion. , The first The 1 bottom portion is located on the second surface side than the first surface side of the top portion of the convex portion. The second recessed portion includes a peripheral wall portion and a second bottom portion, and the peripheral wall portion faces the second surface from the first bottom portion. The second bottom portion is provided at the end portion of the second surface side of the peripheral wall portion to close the end portion. Therefore, the stress in the thickness direction applied from the first surface side of the non-woven fabric can be determined by the foregoing. The first concave portion is cushioned by bending toward the second surface side, and even if it is a nonwoven fabric containing cotton as a constituent component, sufficient flexibility can be ensured.

According to an embodiment of the present invention, the second recessed portion 52 has an opening that is substantially rectangular in plan view, as a whole, protrudes toward the lower surface 1b side of the nonwoven fabric 1, and has a substantially rectangular parallelepiped internal space. The second recessed portions 52 are arranged at regular intervals in the longitudinal direction of each groove portion 5 (that is, the first direction D ₁ or the lengthwise direction of the first recessed portion 51). It is formed separately from the other second recessed portions 52.

Further, in the present embodiment, the plurality of second recessed portions 52 each include a peripheral wall portion 52a of a standing wall shape extending toward the lower surface 1b side in a state continuous with the first bottom portion 51a, and is provided on the lower end side of the peripheral wall portion 52a. The second bottom 52b. The peripheral wall portion 52a line includes: _a first extending peripheral wall portion of one of the pair along the first direction D 52a _1, 52a _1, and ₂ extending along the second direction D 2 of the second circumferential wall portion of one of the pair 52a _2, 52a the first peripheral wall portion _2, a pair 52a _1, 52a ₁ arranged at a position facing each other, the second pair of the peripheral wall portion 52a _2, 52a ₂ are disposed in positions opposed to each other.

As shown in FIGS. 1 and 3, a pair of first peripheral wall portions 52 a ₁ and 52 a ₁ are respectively formed with a hole portion 53 passing from the internal space of the first recessed portion 51 to the second surface 1 b. In this embodiment, the hole portion 53 is provided in each of the pair of first peripheral wall portions 52a ₁ and 52a ₁ , and the hole portion 53 is formed at the position of the first peripheral wall portion 52a ₁ near the second bottom portion 52b. (Therefore, there are two hole portions 53 in one first recessed portion 51). On the other hand, in the pair of second peripheral wall portions 52a ₂ and 52a ₂ , there is no one corresponding to the hole portion 53, and each of the second peripheral wall portions 52a _{2 is in} a state where all of the lower end sides thereof are directly connected to the second bottom portion 52 b.

In the non-woven fabric for an absorbent article of the present invention, the second recessed portion is provided in order to minimize the chance of the groove bottom of the groove portion, more specifically, the first bottom portion of the first recessed portion contacting the wearer's skin, Even if the first bottom is in contact with the skin of the wearer, the contact area can be minimized. That is, the non-woven fabric of the absorbent article of the present invention is configured to easily contact the skin of the wearer in the order of the convex portion, followed by the first bottom portion of the first concave portion, and has a convex portion ratio having the highest softness among the nonwoven fabrics. The above-mentioned first bottom has an ideal structure that makes it easier to contact the skin of the wearer. Furthermore, in the non-woven fabric for absorbent articles of the present invention, considering that the smaller the area of contact with the skin of the wearer, the easier it is to feel soft. The second recessed portion forms a portion where the first recessed portion does not exist, thereby reducing the portion that contacts the wearer's skin at the first bottom portion of the first recessed portion, thereby minimizing the chance of contacting the skin and the contact area.

In addition, the second recessed portion in the present invention is provided in the first recessed portion in order to suppress the abnormal feeling and foreign body feeling caused by contact with the second recessed portion. The first bottom portion minimizes the chance that the second concave portion contacts the skin of the wearer.

In the present invention, the depth of the second recessed portion, that is, the length from the height of the first surface (upper surface) side of the first bottom portion of the first recessed portion to the height of the first surface side of the second bottom portion of the second recessed portion, It is preferably 0.05 to 2 mm, more preferably 0.075 to 1.5 mm, and particularly preferably 0.1 to 1 mm. When the depth of the second recessed portion is less than 0.05 mm, it is difficult to ensure the rigidity of the second bottom portion described later, and the strength in the thickness direction of the nonwoven fabric is likely to be insufficient. On the other hand, when the depth of the second recessed portion exceeds 2 mm, the thickness in the thickness direction tends to be insufficient when bonded to other members of the absorbent article (for example, absorbent body, nonwoven fabric, film, etc.). In addition, when compressed, , May produce a hard feeling.

In addition, regarding the relationship between the depth of the second concave portion and the height of the convex portion, the depth of the second concave portion (that is, the height from the first surface side of the first bottom of the first concave portion to the second of the second concave portion) The length of the height of the first surface side of the bottom portion) is preferably the height of the aforementioned convex portion (that is, the length from the height of 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). 10 ~ 80%, more preferably 15 ~ 70%, especially good 20 ~ 60%. When the depth of the second concave portion is less than 10% of the height of the convex portion, a space cannot be ensured in the hole portion of the peripheral wall portion of the second concave portion. Therefore, the hole portion is formed in an incomplete shape or cannot be formed at all, which is difficult. Obtain excellent flexibility as a non-woven fabric. Conversely, when the depth of the second recessed portion exceeds 80% of the height of the raised portion, the hole portion is formed too large, so the strength of the peripheral wall portion of the second recessed portion is reduced, and the hairs are easily raised. It may cause a decrease in the touch of the nonwoven fabric.

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 particularly preferably 0.75 to 2 mm. When the length of the second recessed portion in the first direction is less than 0.25 mm, the second recessed portion becomes too small, and the above-mentioned effect exerted by the second recessed portion may not be sufficiently obtained. When the length of the second recessed portion in the first direction exceeds 5 mm, the second recessed portion is too long in the first direction. Compared with a flat non-woven fabric or a non-woven fabric having no recessed portions, the flexibility is not easily differentiated and it is difficult to obtain. 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 particularly preferably 0.75 to 2 mm. When the length in the second direction of the second recessed portion is less than 0.25 mm, the second recessed portion becomes too small, and in particular, the formation of the second bottom portion becomes incomplete. Therefore, the above-mentioned effect exerted by the second recessed portion may not be possible. Fully acquired. When the length of the second recessed portion in the second direction exceeds 5 mm, the second recessed portion becomes excessively large, and when it comes into contact with the non-woven fabric, an abnormal feeling and a foreign body feeling tend to occur.

The pitch of the second recesses in the second direction (that is, the distance between adjacent second recesses in the second direction) is not particularly limited, but is preferably 1.5 mm or less. When the pitch of the second recessed portion in the second direction is 1.5 mm or less, the cotton in the first fiber layer constituting the non-woven fabric is easily held at the second bottom portion of the second recessed portion. Therefore, at the second bottom portion, The above-mentioned fission of the fibrous layer and interlayer peeling between the fibrous layers are less likely to occur.

In the present invention, regarding the hole portion formed in the peripheral wall portion of the second recessed portion, the length of the largest portion of the hole portion (in the case of this embodiment, the length in the first direction) depends on the second recessed portion. The size is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and particularly preferably 0.75 to 2 mm. When the length of the largest portion of the hole portion is less than 0.25 mm, the formation of the hole portion is incomplete, the flexibility of the second concave portion cannot be sufficiently ensured, and the tension of the fiber of the convex portion is not easily reduced, and the convex portion is not easily reduced. The softness cannot be fully ensured. When the length of the largest portion of the hole portion exceeds 5 mm, the hole portion becomes too large, and the peripheral portion of the hole portion is liable to fluff, and when it comes into contact with the non-woven fabric, abnormal feeling and foreign body sensation are likely to occur, which may cause the non-woven touch to be reduced.

On the other hand, although the maximum length in the height direction of the hole portion (that is, the thickness direction of the non-woven fabric) also depends on the depth of the aforementioned second concave portion, it is preferably 0.1 to 5 mm, more preferably 0.25 to 3 mm, and particularly preferably 0.5 ~ 2mm. When the maximum length in the height direction of the hole portion is less than 0.1 mm, the formation of the hole portion is incomplete, the flexibility of the second concave portion cannot be sufficiently ensured, and the tension of the fibers of the convex portion is not easily reduced. The flexibility of the part cannot be sufficiently ensured. When the maximum length in the height direction of the hole portion exceeds 5 mm, the hole portion becomes too large, and the peripheral edge portion of the hole portion is liable to fluff, and when it comes into contact with the non-woven fabric, abnormal feeling and foreign body sensation are likely to occur, which may cause the non-woven touch to be reduced.

In order to release the tension of the fibers of the convex portion, the freedom of movement of the entire convex portion or the fibers used to form the convex portion is improved, and the flexibility of the convex portion is improved. More specifically, the flexibility of the convex portion toward the thickness of the nonwoven fabric is improved. , And the softness (especially the softness in the width direction) when the skin slides along the first direction (length direction) and the second direction (width direction) of the non-woven fabric to ensure smoothness. The aforementioned holes in the present invention are only provided The first peripheral wall portion of the second recessed portion. By forming the hole portion, it is possible to impart excellent hard and soft feel to the convex portion (excellent flexibility toward the thickness direction of the nonwoven fabric) and excellent rough feel to the second direction of the nonwoven fabric (the planar direction of the nonwoven fabric (especially the first 2 directions), both excellent smoothness), can ensure the excellent hard and soft feel and rough feel of the whole non-woven fabric, and obtain a soft touch.

In addition, in the present invention, when the skin is slid along the first direction of the non-woven fabric (that is, the extending direction of the convex portion and the groove portion), in order to prevent the height difference generated by the second concave portion from being caught on the skin, The smoothness of the nonwoven fabric in the first direction has no hole formed in the second peripheral wall portion of the second recessed portion.

That is, the second peripheral wall portion is configured to be connected to the first bottom portion of the first recessed portion and the second bottom portion of the second recessed portion to form a seamless body. Therefore, when the skin slides in the first direction of the non-woven fabric, the skin The height difference of the second recessed portion is not easily felt, and it is easy to move smoothly along the convex portion and the groove portion. In this way, the softness of the convex portion and the softness of the fiber can ensure smoothness in the first direction of the nonwoven fabric.

In addition, in the present invention, the hole portion is as far as possible away from the convex portion and the first bottom portion of the first recessed portion, which minimizes the chance of the wearer's skin contacting the hole portion, and suppresses the occurrence of abnormalities and foreign body sensations. The hole portion is formed near the second bottom portion of the first peripheral wall portion of the second recessed portion. In this way, it is more stable to ensure that the skin is flat along the non-woven fabric. Smoothness when sliding in the face direction.

In the nonwoven fabric for an absorbent article of the present embodiment, the hole portion 53 is provided with a peripheral edge portion 53a which is not formed by melting the thermoplastic resin fibers contained in the nonwoven fabric 1 but breaking the thermoplastic resin fibers. More specifically, as shown in FIG. 3, the peripheral edge portion 53 a of the hole portion 53 includes the break of the fracture fiber 54 having the fracture end portion 54 a formed by the fracture among the thermoplastic resin fibers included in the nonwoven fabric 1.端 部 54a。 End 54a.

Therefore, the peripheral edge portion 53a of the hole portion 53 does not have a portion where the thermoplastic resin fiber is melted and hardened, but a portion of the soft thermoplastic resin fiber or a portion formed by breaking the thermoplastic resin fiber is provided. The broken fibers 54 are formed at the broken ends 54a. In this way, even if the skin of the wearer of the absorbent article touches the peripheral edge portion 53a of the hole portion 53, the thermoplastic resin fiber hardened by melting does not exist, and the rigidity and rough feeling of the nonwoven fabric can be suppressed as much as possible.

Here, the broken fibers 54, forming a fiber-based portion of the first peripheral wall portion 52a ₁ of the thermoplastic resin fiber and having: the thermoplastic resin fiber is stretched in the longitudinal direction of the cutting or physically formed by break Rupture end 54a.

Therefore, the broken end portion 54a does not melt and round the fiber end portion to make the fiber diameter larger as in the case of melting the thermoplastic resin fiber, but cuts the fiber to make the front end thinner, or It is a state in which the fiber diameter hardly changes. In this way, even if the skin of the wearer contacts the peripheral edge portion 53 a of the hole portion 53, it is possible to suppress hardening and fiber hooking. The unusual feeling brought by the residence occurs.

Further, as shown in FIG. 3, in the internal space 53 b of the hole portion 53, a part of the fibers 55 of the thermoplastic resin fibers cross. In addition, in a part of the broken fibers 54, the broken end portion 54 a is extended into the internal space 53 b of the hole portion 53.

Therefore, in the internal space 53b of the hole portion 53, the fibers 55 that traverse the internal space 53b and a part of the extended fibers are mixed, rather than a completely open space. In this way, a part of the thermoplastic resin fiber is traversed in the internal space of the hole portion, and the thermoplastic resin fiber traversing the internal space can minimize the peripheral surface, bottom and hole of the recessed portion even if the skin of the wearer contacts the hole portion. The difference in the sensation of the parts makes the wearer less prone to abnormal feelings. That is, the thermoplastic resin fibers that traverse the internal space of the hole portion can prevent the wearer's skin from completely penetrating the hole portion and reaching the second surface side (lower surface side) of the non-woven fabric, so that the peripheral wall portion or the second bottom portion and the hole portion can be prevented. The difference in height between the borders becomes smaller in touch. In this way, the touch of the non-woven fabric becomes smoother. Even if the wearer's skin contacts the hole, it is not easy for the wearer to have an abnormal feeling.

In the present invention, the opening ratio of the internal space of the hole portion is preferably 1 to 50%, more preferably 1.5 to 35%, and particularly preferably 2.5 to 20%. When the opening ratio of the internal space of the hole portion is less than 1%, the opening ratio is too low to provide freedom to the convex portion and the fibers of the convex portion, and the flexibility of the convex portion cannot be sufficiently ensured. When 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 (in the case of this embodiment, the first peripheral wall portion 52a ₁ ) is likely to decrease, and the Boundaries are easy to recognize on the touch. However, depending on the type, application, etc. of the non-woven absorbent article, the opening ratio of the internal space of the hole portion may be outside the above range and can be arbitrarily set.

Hereinafter, the manufacturing method of the nonwoven fabric 1 for absorbent articles which has the said specific uneven | corrugated structure is demonstrated in detail with reference to drawings.

5 to 8 show an example of a manufacturing apparatus for manufacturing the nonwoven fabric 1 for absorbent articles, and the manufacturing apparatus 6 is configured to include two fiber layers including the first fiber layer 2 and the second fiber layer 3 The fiber laminate 7 is processed into the nonwoven fabric 1 for absorbent articles having the specific uneven structure described above. The first fiber layer 2 contains cotton 2a and thermoplastic resin fibers 2b; the second fiber layer 3 is adjacent to one side of the first fiber layer 2 and contains thermoplastic resin fibers 3a and does not contain cotton. The manufacturing device 6 includes an unwinding device 61, a preheating device 62, and a shaping device 63. The unwinding device 61 winds the fiber laminated body 7 before processing into a roll shape, and unwinds the fiber laminated body 7 toward the conveying direction MD. The preheating device 62 is configured to pass the unwinding device 61 The unwinded fiber laminate 7 is preheated; the shaping device 63 extends the fiber laminate 7 after the preheating is applied to form a convex portion and a groove portion (including the first concave portion and the second concave portion). Concave and convex shape processing.

The preheating device 62 of this embodiment is provided with a pair of upper and lower heating rollers 62a, 62b, and a fiber laminate 7 of a processing object which is unwound from the unwinding device 61 and transported therefrom, and is wound under the rotation After heating on the heating roller 62b, it is transferred to the heating roller 62a which is rotating upward, and the aforementioned fibers are laminated by the heating roller 62a The body 7 is heated.

In addition, the forming device 63 is provided with a pair of upper and lower extension rollers 63a and 63b. As shown in FIG. 6, the upper extension roller 63a is provided with a certain interval in the width direction of the roller and along the upper side. The outer peripheral surface of the extension roller 63a is provided with a plurality of rows of ridges 63a ₁ parallel to each other and a plurality of rows of grooves 63a ₂ provided between two adjacent ridges 63a ₁ and 63a ₁ . On the other hand, as shown in FIGS. 6 and 7, includes a circumferential surface 63b ₂ extending beyond the roller 63b below: a groove 63a is provided with a plurality of rollers extending above the engagement of the pins 63a ₂ 63b _1. As shown in FIG. 8, the pins 63b ₁ are arranged at a certain interval in the width direction of the roller so as not to contact the protruding ribs 63a _{1 of the} upper extending roller 63a, and in the circumferential direction of the roller. It is arranged in a substantially linear shape at regular intervals along the outer peripheral surface 63b ₂ . Further, the present embodiment extends downward form the roller 63b, as illustrated in FIG 7, a plurality of pins _{63b. 1} are outside the roller 63b extending below the circumferential surface 63b ₂ are arranged in a staggered manner.

When manufacturing the nonwoven fabric 1 for absorbent articles using the manufacturing apparatus 6 comprised in this way, it is performed sequentially: apply the preheating preheating process to the fiber laminated body 7 of the processing object unwound from the unwinding apparatus 61, and After the pre-heating step, the fiber laminated body 7 is extended to perform a concave-convex forming step.

The aforementioned preheating step is to unwind the processing target fiber laminated body 7 and the preheating device 62 which are unwound from the unwinding device 61 and are conveyed along the conveying direction MD. The outer periphery of the next pair of heating rollers 62a, 62b is rotating. By making surface contact, the aforementioned fiber laminate 7 is heated to apply preheating. 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, when the thermoplastic resin fibers are polyethylene terephthalate (PET) and high density polyethylene ( In the case of a core-sheath composite fiber composed of HDPE), the temperature of the outer peripheral surface of the heating roller is preferably about 60 to 120 ° C.

In the aforementioned forming step, the fiber laminated body 7 that has been carried through the preheating step is inserted into one of the forming devices 63 while meshing while rotating between the next pair of extension rollers 63a and 63b, above the meshing with each other. extending the roller 63a of the ridges 63a and grooves _{63a. 1} and ₂ the roller extending below the pin 63b of the fiber extends between the laminate 7 is _{performed. 1} 63b shaped. In the forming step, in order to facilitate the forming, it is preferable to perform the forming while heating the pair of upper and lower extension rollers 63a and 63b to 60 to 120 ° C.

In the aforementioned forming step, the protrusion 63a _{1 of the} upper extension roller 63a presses a portion in contact with the fiber laminated body 7 toward the lower extension roller 63b, thereby shaping the convex portion 4. On the other hand, the circumferential direction extending roller downward 63b of a row of a plurality of pins _{63b. 1,} the contact of the pin leading end portion _{63b. 1} fiber laminate 7 is pressed into the extending rollers above the corresponding 63a of recess 63a ₂ within. At this time, the portion of the fiber laminate 7 that is in a non-contact state with the pin 63b ₁ and is drawn into the groove 63a ₂ becomes the first recessed portion 51 of the groove portion 5. In addition, the portion in contact with the front end portion of the pin 63b ₁ is forced into the groove 63a ₂ to be shaped, thereby forming a first portion extending in a direction in which the convex portion 4 and the groove portion 5 extend. extension of the peripheral wall portion 52a ₁ and the roller toward the width direction of the second peripheral wall portion 52a _2, 52b 2 and the bottom of the first portion 52 of the second recess.

Second recessed portions of the second bottom portion 52b 52 of the, as it is formed, in the case by extending the roller 63a and the extending roller downward 63b above the fiber laminate 7 bitten state, the pin leading end portion _{63b. 1} of the fiber Since the abutting portion of the laminated body 7 is strongly pressed into the groove 63a ₂ , its fiber density is substantially higher than other portions of the nonwoven fabric. In this way, when the fiber density of the second bottom portion 52b disposed between two adjacent convex portions 4 is relatively high, the thermoplastic resin fibers having a smaller fiber diameter included in the first fiber layer 2 constituting the nonwoven fabric 1 2b can be more entangled with the cotton 2a contained in the first fiber layer 2 and the thermoplastic resin fiber 3a contained in the second fiber layer 3, so the second bottom portion 52b is less likely to cause the above-mentioned habit. The fibrous layer is split as in the known technique, and the interlayer peeling between the fibrous layers is performed. In the non-woven fabric, a plurality of such portions that are less prone to fibrous layer splitting and interlayer peeling between the fibrous layers (that is, the second bottom portion) are locally provided. Interlayer peeling between layers occurs locally, and fibrous layer splitting and interlayer peeling between the fiber layers do not occur in the second bottom portion, which can effectively prevent a decrease in the strength of the entire nonwoven fabric.

In the structure of the nonwoven fabric 1, a density gradient exists in the thickness direction D _T from the convex portion 4 having a relatively low fiber density to the second bottom portion 52 b of the second concave portion 52 having the highest fiber density. Body fluids such as urine and menstrual blood supplied on the surface 1a (first surface) side are easily introduced from the convex portion 4 on the upper surface 1a side of the nonwoven fabric 1 through the second bottom portion 52b to the lower surface 1b (second surface) side, and The excellent absorbency (especially absorption speed, liquid transfer properties, etc.) of a nonwoven fabric for an absorbent article can be exhibited.

Further, in the fiber laminated body 7, a portion in contact with both ends in the width direction (the width direction of the roller) of the front end portion of the pin 63b ₁ is also subjected to the projection 63 a ₁ to extend the roller in which the fiber laminated body 7 faces downward. The pin 63b ₁ pulls out the thermoplastic resin fibers used to form the first peripheral wall portion 52a ₁ or breaks the fibers to form a broken fiber 54 having a broken end portion 54a due to the effect of the tension generated when it is pushed in the direction of 63b. In this manner, the hole portion 53 including the broken end portion 54 a of the broken fiber 54 is formed in the second recessed portion 52. A part of the thermoplastic resin fibers remains in a state that crosses the internal space 53b of the hole portion 53, and a broken end portion 54a of a part of the broken fibers 54 is extended into the internal space 53b.

Here, the hole portion 53 is formed in the first peripheral wall portion 52a ₁ . The first peripheral wall portion 52a ₁ is the direction of fiber conveying direction of the laminate and the object along the body 7 parallel to MD, i.e., extending along the rollers 63a, 63b and the rotational direction of the convex portion 4 and the extension groove portion 5 Set the direction.

The fiber laminate having the uneven structure provided through the above-mentioned forming step is formed with the above-mentioned convex portion 4 and the groove portion 5 including the first concave portion 51 and the second concave portion 52 to form a nonwoven fabric 1 for an absorbent article. The non-woven fabric 1 for an absorbent article is then applied to a surface sheet, a leak-proof wall, and the like of an absorbent article such as disposable diapers and sanitary napkins.

Hereinafter, nonwoven fabrics for absorbent articles according to other embodiments of the present invention will be described.

In another embodiment of the present invention, the nonwoven fabric for absorbent articles is a fiber laminate composed of three fiber layers, and the fiber laminate (non-woven fabric) includes a third fiber layer for forming a first surface of the nonwoven fabric. (Contains thermoplastic resin fibers and does not contain cotton), the second fiber layer (intermediate layer) adjacent to the surface on the second surface side of the third fiber layer, and the surface on the second surface side of the second fiber layer The first fiber layer adjacent to and containing cotton. When the non-woven fabric for an absorbent article having such a structure is used as a surface sheet of an absorbent article in such a manner that the first surface of the non-woven fabric becomes the skin-facing surface of the wearer, Between the third fiber layer and the cotton-containing first fiber layer, the second fiber layer as an intermediate layer is interposed to isolate the third fiber layer and the first fiber layer, and to isolate the cotton of the first fiber layer. Body fluids such as urine that are absorbed and held are not easily transmitted to the third fiber layer and further to the skin of the wearer, so it is not easy for the wearer to feel wet or stuffy, and the wearer does not feel uncomfortable. .

The specific structure of the three-layer fiber laminate in this other embodiment is, for example, the structure shown below.

[Fibrous layer on the first side (opposite to the skin)] (third fibrous layer)

PET / PE core-sheath composite fiber with a fineness of 2.8 dtex, a fiber length of 45 mm, and a basis weight of 10 g / m ²

[Intermediate layer] (second fiber layer)

PET / PE core-sheath composite fiber with a fineness of 2.8 dtex, a fiber length of 45 mm, and a basis weight of 10 g / m ²

[The second surface (non-skin facing surface) side fiber layer] (the first fiber layer)

PET / PE core-sheath composite fiber with a fineness of 2.2 dtex, a fiber length of 44 mm and a basis weight of 8 g / m ² , a PET fineness of 1.7 dtex, a fiber length of 45 mm and a basis weight of 1 g / m ² with a PET / PE core-sheath composite fiber, and Mixture of cotton weighing 1g / m ²

In another embodiment of the present invention, the non-woven fabric for absorbent articles is a fiber laminate composed of three fiber layers, and the fiber laminate (non-woven fabric) includes the second fiber forming the first surface of the non-woven fabric. A first fiber layer (intermediate layer) adjacent to the surface on the second surface side of the second fiber layer and containing cotton, and a third fiber layer adjacent to the surface on the second surface side of the first fiber layer The third fiber layer contains thermoplastic resin fibers and does not contain cotton. The non-woven fabric for an absorbent article configured as described above is used as the surface sheet of the absorbent article in such a manner that the first surface of the non-woven fabric becomes the skin-facing surface of the wearer. The third fiber layer is interposed between the gap portions on the second surface side (non-skin-facing surface side) of the convex portion of the first surface of the nonwoven fabric, and the third fiber layer is arranged from the second fiber side to the third fiber layer. Moisture generated by evaporation of bodily fluids such as urine released by the absorber can be absorbed and held by the cotton of the first fiber layer, and sealed in the gap portion and the third fiber layer (the gap portion The function is used as a space to maintain the moisture state of the moisture emitted from the absorbent body; the third fiber layer is used as an auxiliary space to seal the moisture emitted from the absorbent body). As a result, the moisture emitted from the absorbent body can be effectively confined in a region closer to the second surface side than the first fiber layer, and it becomes difficult for the wearer to feel stuffy or the like.

The specific structure of the three-layer fiber laminate in this other embodiment is, for example, the structure shown below.

[Fibrous layer on the first side (opposite to the skin)] (second fibrous layer)

PET / PE core-sheath composite fiber with a fineness of 2.8 dtex, a fiber length of 45 mm, and a basis weight of 10 g / m ²

[Intermediate layer] (first fiber layer)

PET / PE core-sheath composite fiber with a fineness of 2.2 dtex, a fiber length of 44 mm and a basis weight of 8 g / m ² , PET / PE core-sheath composite fiber with a fineness of 1.7 dtex, a fiber length of 45 mm and a basis weight of 1 g / m ² , and Mixture of cotton weighing 1g / m ²

[The second surface (non-skin facing surface) side fiber layer] (the third fiber layer)

PET / PE core-sheath composite fiber with 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 embodiments, the thermoplastic resin fibers contained in the third fiber layer are not particularly limited, and the same ones as the thermoplastic resin fibers contained in the first fiber layer or the second fiber layer can be used. Furthermore, in these embodiments, it is preferable that the basis weight of the thermoplastic resin fibers in each fiber layer is the same, and the fiber diameter (fineness) of the thermoplastic resin fibers contained in the second fiber layer and the third fiber layer is preferably, Each has a fiber diameter (fineness) larger than that of the thermoplastic resin fibers contained in the first fiber layer. If the non-woven fabric (fiber laminated body) has such a structure, the amount of fibers (the number of fibers) of the thermoplastic resin fibers contained in the first fiber layer is necessarily greater than that of the second fiber layer and the third fiber layer, so that The strength of the first fiber layer containing cotton is further improved. In addition, such a non-woven fabric, the first fiber The thermoplastic resin fibers of the layer are easily entangled with the thermoplastic resin fibers of the second fiber layer or the third fiber layer, and even if the fiber layer constituting the nonwoven fabric contains cotton, interlayer peeling between the fiber layers does not easily occur.

Further, in the absorbent article of one embodiment of the present invention, non-woven fabric 1, the hole section the second recess 52 of the 53 lines disposed in a direction of the first direction D ₁ of the first peripheral wall portion of one of the pair 52a ₁ is formed, but in the absorbent article of the present invention is non-woven fabric is not limited to this aspect, for example, holes may be provided in one of which the peripheral wall 52a ₁ of the first portion of the pair of the peripheral wall portion, may also be disposed in the second direction The pair of second peripheral wall portions formed in the direction D ₂ or any one of the peripheral wall portions.

Furthermore, in the nonwoven fabric 1 for absorbent articles of the above embodiment, the hole portion 53 is provided near the second bottom portion 52b of the peripheral wall portion 52a of the second recessed portion 52. However, in the nonwoven fabric for absorbent articles of the present invention, It is not limited to this aspect, and the said hole part can be provided in arbitrary positions in the range which does not impair the softness of a nonwoven fabric.

Moreover, in the nonwoven fabric 1 for absorbent articles of the above-mentioned embodiment, the fibers 55 of one part of the thermoplastic resin fibers are crossed in the internal space 53b of the hole portion 53, but the nonwoven fabric for absorbent articles of the present invention In this way, the fibers that cross the internal space of the hole portion may not exist. In addition, in the present invention, it is not necessary to extend the broken end portion of the broken fiber into the internal space of the hole portion as in the above embodiment.

In the nonwoven fabric 1 for an absorbent article according to the above embodiment, the second recessed portion 52 is formed in a substantially rectangular parallelepiped shape. However, in the nonwoven fabric for an absorbent article of the present invention, the shape of the second recessed portion is not particularly limited. The system can adopt any shape such as a column shape, a corner column shape, and the like.

Further, in the above embodiment, the convex portion 4 is a first direction D 1 extends continuously from ₁ toward the non-woven fabric, but the first direction in the absorbent article of the present invention, non-woven fabric, the convex portion is not necessarily toward the non-woven fabric Continuous extension or intermittent extension is also possible. However, the second concave portion is preferably provided on the first bottom portion of the first concave portion sandwiched between the continuous portions of the convex portion. In this way, it is easy for the convex portion to contact the wearer's skin first, and to prevent the wearer's skin from It is easy to contact the second recessed portion, and it is possible to suppress an abnormal feeling and a foreign body feeling caused by the contact with the second recessed portion.

The non-woven fabric for an absorbent article of the present invention is not limited to the above-mentioned embodiments and the like, and can be appropriately combined, changed, and the like within a range that does not deviate from the purpose and interest of the present invention. Also in this specification, ordinal numbers such as "first" and "second" are used to distinguish items to which the ordinal number is added, and do not mean the order, priority, and importance of each item.

Claims (5)

A non-woven fabric for an absorbent article is a non-woven fabric for an absorbent article including at least two fiber layers including a first fiber layer and a second fiber layer, and the first fiber layer includes cotton and thermoplastic resin fibers; 2 fiber layers are adjacent to at least one side of the first fiber layer and contain thermoplastic resin fibers and do not contain cotton; the fiber diameter of the thermoplastic resin fibers contained in the first fiber layer is greater than that of the second fiber layer The aforementioned thermoplastic resin fiber has a smaller fiber diameter; the aforementioned nonwoven fabric has a first surface and a second surface opposite to the first surface; the aforementioned nonwoven fabric has a plurality of convex portions and a plurality of groove portions, and the plurality of convex portions , Is provided on the first surface of the non-woven fabric to extend in the first direction and is provided in the second direction orthogonal to the first direction at a predetermined interval and protrudes toward the first surface; the plurality of The groove portion extends toward the first direction and is provided between the convex portions adjacent in the second direction and is recessed toward the second surface; the groove portion has a first recessed portion and a plurality of Each 2 recessed portions, the first recessed portion is provided with a first bottom portion, and the first bottom portion is positioned closer to the second surface side than the first surface side of the top portion of the convex portion; the plurality of second recessed portions are attached to the foregoing The first recessed portion is provided discontinuously in the first direction and is recessed from the first bottom portion toward the second surface; the second recessed portion includes a peripheral wall portion and a second bottom portion, and the peripheral wall portion is from the first bottom portion The second bottom portion is provided to extend toward the second surface side, and the end portion of the second bottom portion on the second surface side of the peripheral wall portion is provided to close the second end portion. End, and has the highest fiber density among the aforementioned non-woven fabrics. The non-woven fabric for absorbent articles according to item 1 of the scope of patent application, wherein the peripheral wall portion includes: a first peripheral wall portion along one pair of the first direction; and a pair of along the second direction. The second peripheral wall portion is provided with at least one of the first peripheral wall portions of the pair, and a hole portion leading to the second surface. The nonwoven fabric for absorbent articles according to item 1 or 2 of the scope of patent application, wherein the first surface of the nonwoven fabric is formed of a fiber layer other than the first fiber layer. The nonwoven fabric for absorbent articles according to item 1 or 2 of the scope of patent application, wherein the pitch of the second recessed portion in the second direction is 1.5 mm or less. The non-woven fabric for absorbent articles according to item 1 or 2 of the scope of patent application, wherein the non-woven fabric includes the first fiber layer forming the second surface and a surface on the first surface side of the first fiber layer The adjacent second fiber layer and the third fiber layer adjacent to the surface on the first surface side of the second fiber layer, the third fiber layer contains thermoplastic resin fibers and does not contain cotton; thermoplastic resin fibers of each fiber layer The basis weight is the same, and the fiber diameter of the thermoplastic resin fibers contained in the third fiber layer is the same as or larger than the fiber diameter of the thermoplastic resin fibers contained in the second fiber layer.