Moisture-absorbing sheet, disposable wearing article, and method for producing the same

Abstract

To provide a moisture-absorbing sheet excellent in air permeability for releasing moisture, and excellent in air permeability for efficiently supplying moisture to a moisture-absorbing material, and to provide a disposable wearing article and a manufacturing method of the same.SOLUTION: A moisture-absorbing sheet 15 comprises: a nonwoven fabric 16 in which thin wall parts 16t constricted in a thickness direction are repeatedly formed at intervals; and minute fibrous cellulose aggregates 17 adhering into the thin wall parts 16t.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a moisture-absorbing sheet, a disposable wearing article, and a method for manufacturing the same.

Background Art

[0002] In disposable wearing articles such as disposable diapers and sanitary napkins, it has been proposed to have hygroscopicity for various reasons.

[0003] For example, disposable wearing articles such as disposable diapers and sanitary napkins have an absorber that absorbs excreted fluids such as urine, and a liquid-impermeable resin film that covers the back side of the absorber. In order to prevent stuffiness during wearing, a liquid-impermeable resin film having moisture permeability in the thickness direction has been used (see, for example, Patent Documents 1 and 2). In addition, in many absorbent articles, in order to make the outer surface of the product feel like cloth and have an appearance like cloth, the back side of the liquid-impermeable resin film has also been covered with an outer packaging nonwoven fabric (see, for example, Patent Document 2).

[0004] However, in conventional absorbent articles, the high moisture permeability of the liquid-impermeable resin film has been a problem. After the absorber has absorbed excreted fluids, etc., the outer surface of the product or the underwear may retain moisture, and when touched by hand, it may be misperceived as leaking.

[0005] This problem can be solved by reducing the moisture permeability of the liquid-impermeable resin film, but in that case, a decrease in the ability to prevent stuffiness cannot be avoided. Therefore, for example, it has been proposed to provide a moisture-absorbing layer on the liquid-impermeable resin film or the outer packaging nonwoven fabric (see, for example, Patent Document 1).

[0006] In addition, generally, disposable wearing articles are known to have poor breathability, and it has also been proposed to attach a moisture-absorbing sheet to prevent the inside of the disposable wearing article from becoming stuffy during wearing (see, for example, Patent Document 3).

[0007] Furthermore, a moisture-absorbing sheet may be used as a product packaging material or within a product packaging (see, for example, Patent Document 4).

[0008] However, in the case of a moisture-absorbing sheet, not only the performance of the moisture-absorbing material, but also the air permeability for releasing moisture and the air permeability for supplying moisture to the moisture-absorbing material are important, and there has been room for improvement in this regard for conventional ones.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0010] Therefore, the main problem of the present invention is to provide a moisture-absorbing sheet, a disposable wearable article, and a method for manufacturing the same, which are excellent in air permeability for releasing moisture and air permeability for efficiently supplying moisture to the moisture-absorbing material.

Means for Solving the Problems

[0011] The moisture-absorbing sheet and the like that solve the above problems are as follows. <First Aspect> A non-woven fabric in which thin portions that have shrunk in the thickness direction are repeatedly formed at intervals, and a microfiber-like cellulose aggregate attached within the thin portions, characterized by being a moisture-absorbing sheet.

[0012] (Function and Effect) This moisture-absorbing sheet is characterized in that it is based on a non-woven fabric in which thin portions are repeatedly formed at intervals, and a micro-fibrous cellulose aggregate having high moisture absorbency is adhered within the thin portions. Therefore, even when this moisture-absorbing sheet is used while being sandwiched between objects or members, a ventilation gap is formed between the object or member and the thin portion of the moisture-absorbing sheet. Thus, in this moisture-absorbing sheet, moisture can be released along the surface of the moisture-absorbing sheet through this ventilation gap. Also, in the process, moisture can be efficiently supplied to the micro-fibrous cellulose aggregate, which is a moisture-absorbing material, and absorbed. Such a moisture-absorbing sheet can be used alone or can be used as a member of a disposable wearing article as described later.

[0013] <Second Aspect> Other than the thin portions, it does not have the micro-fibrous cellulose aggregate. The moisture-absorbing sheet of the first aspect.

[0014] (Function and Effect) The micro-fibrous cellulose aggregate is hard. Therefore, it is preferable that the micro-fibrous cellulose aggregate is adhered only to the thin portions of the moisture-absorbing sheet. Thereby, other than the thin portions in the moisture-absorbing sheet can be deformed flexibly, and it becomes difficult for the user or wearer to touch the hard thin portions, or the hardness is less likely to be transmitted to the skin.

[0015] <Third Aspect> The thin portions are provided in a striped or lattice pattern. The moisture-absorbing sheet of the first or second aspect.

[0016] (Function and Effect) When the thin portions are provided in a striped or lattice pattern, the continuity of the ventilation gaps is increased. Therefore, the ventilation property for releasing moisture and the ventilation property for efficiently supplying moisture to the moisture-absorbing material are further improved.

[0017] <Fourth Aspect> The non-woven fabric constituting the moisture-absorbing sheet is a short-fiber non-woven fabric with a fineness of 2 to 10 dtex and a basis weight of 20 to 40 g / m 2 and The adhesion amount of the microfibrous cellulose aggregate in the thin part is 0.1 to 5.0 g / m 2 is of The moisture-absorbing sheet according to the first or second aspect.

[0018] (Function and effect) The nonwoven fabric constituting the moisture-absorbing sheet is not particularly limited, but it is preferably bulky and has excellent formability, so it is preferably a nonwoven fabric within the above range. Also, in order to improve the moisture absorption property, the adhesion amount of the microfibrous cellulose aggregate cannot be too much, but if it is too much, the product will become unnecessarily hard. Therefore, the content of the microfibrous cellulose aggregate in the thin part is preferably within the above range.

[0019] <The fifth aspect> An absorber, A liquid-impermeable resin film having air permeability provided on the back side of the absorber, An outer packaging nonwoven fabric covering the back surface of the liquid-impermeable resin film, In a disposable wearing article having A moisture-absorbing sheet provided between the liquid-impermeable resin film and the outer packaging nonwoven fabric, The moisture-absorbing sheet has a nonwoven fabric in which thin parts shrunk in the thickness direction are repeatedly formed at intervals, and a microfibrous cellulose aggregate adhered in the thin parts, Between the outer packaging nonwoven fabric and the thin part, and between the liquid-impermeable resin film the thin-walled part and and each have an air ventilation gap, A disposable wearing article characterized by this.

[0020] (Function and effect) This disposable wearing article has the first aspect moisture-absorbing sheet interposed between the liquid-impermeable resin film and the outer packaging nonwoven fabric to form an air ventilation gap. Therefore, according to this disposable wearing article, the moisture discharged from the liquid-impermeable resin film that increases after absorbing excreted liquid can be effectively absorbed by the moisture-absorbing sheet, and it is less likely to make the outer surface of the product and the underwear feel wet.

[0021] <Sixth Aspect> It has a breathable skin contact layer that contacts the wearer's skin and a moisture-absorbing sheet provided so as to have a portion adjacent to the back side of the skin contact layer. The moisture-absorbing sheet has a non-woven fabric in which thin portions shrunk in the thickness direction are repeatedly formed at intervals and fine fibrous cellulose aggregates attached in the thin portions. There are ventilation gaps between the skin contact layer and the thin portions respectively. A disposable wearing article, characterized in that.

[0022] (Function and Effect) This disposable wearing article is provided with a moisture-absorbing sheet so as to have a portion adjacent to the back side of the skin contact layer in order to prevent stuffiness during wearing. Thereby, it is possible to prevent stuffiness by efficiently absorbing moisture inside the disposable wearing article during wearing or allowing it to escape to the outside.

[0023] <Seventh Aspect> A process for manufacturing a moisture-absorbing sheet, in which a dispersion of fine fibrous cellulose is applied to a non-woven fabric in a pattern of repeating at intervals and the dispersion is dried, thereby forming a thin portion in the applied portion of the dispersion and forming fine fibrous cellulose aggregates in the thin portion, and A process for manufacturing a disposable wearing article, in which the moisture-absorbing sheet is attached between members overlapping in the thickness direction of the disposable wearing article and there is a ventilation gap between the member and the thin portion, including A method for manufacturing a disposable wearing article, characterized in that.

[0024] (Function and Effect) When a dispersion of fine fibrous cellulose is applied to a non-woven fabric and then the dispersion in the applied portion is dried, when fine fibrous cellulose aggregates are formed, the volume of the fine fibrous cellulose aggregates gradually decreases. Along with this, the volume of the applied portion of the dispersion of the non-woven fabric also decreases, and a thin portion is automatically formed. This manufacturing method utilizes this. For example, a thin portion may be formed on the nonwoven fabric to be a moisture-absorbing sheet by embossing, or the microfibrous cellulose aggregate may be attached to the thin portion thereafter. However, according to this manufacturing method, a moisture-absorbing sheet can be formed simply by applying a dispersion of microfibrous cellulose in a desired pattern to the nonwoven fabric to be a moisture-absorbing sheet and drying it. Also, if the dispersion of microfibrous cellulose is applied to the nonwoven fabric and then attached to other members of the disposable wearing article before drying (that is, before the thin portion is formed), there is a risk that the formation of the ventilation gap will be insufficient. On the other hand, in this manufacturing method, since the disposable wearing article is manufactured using the moisture-absorbing sheet after drying, a good ventilation gap can be formed. Therefore, this manufacturing method is to attach the cover layer after the formation of the thin portion.

Advantages of the Invention

[0025] According to the present invention, advantages such as being excellent in air permeability for releasing moisture and air permeability for efficiently supplying moisture to the moisture-absorbing material are brought about.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0027] Figs. 1 to 7 show an example of a tape-type disposable diaper. In the figures, reference symbol W indicates the overall width of the diaper excluding the connecting tape, reference symbol L indicates the overall length of the diaper, and the dotted pattern part in the cross-sectional view indicates an adhesive as a joining means for joining the respective constituent members located on the front side and the back side thereof. The adhesive is applied by hot melt adhesive in a solid, bead, curtain, summit or spiral coating, or pattern coating (transfer of hot melt adhesive by intaglio printing), or the fixing part of the elastic member is formed by applying it to the outer peripheral surface of the elastic member by caulking gun or Surelap coating instead of or together with this. As the hot melt adhesive, there are types such as EVA-based, pressure-sensitive rubber-based (elastomer-based), olefin-based, polyester-polyamide-based, etc., and it can be used without particular limitation. As the joining means for joining the respective constituent members, means such as material welding such as heat sealing or ultrasonic sealing can also be used.

[0028] This tape-type disposable diaper has an absorber 56, a liquid-permeable topsheet 30 covering the front side of the absorber 56, a liquid-impermeable resin film 11 covering the back side of the absorber 56, and an outer packaging non-woven fabric 12 covering the back side of the liquid-impermeable resin film 11 and constituting the outer surface of the product. Reference symbol F indicates the ventral part located on the front side from the center in the front-rear direction, and reference symbol B indicates the dorsal part located on the back side from the center in the front-rear direction.

[0029] Hereinafter, the materials and characteristic parts of each part will be described in order. (Absorber) The absorber 56 is a part that absorbs and holds excreted fluid and can be formed by an aggregate of fibers. As this fiber aggregate, in addition to those formed by laminating short fibers such as cotton pulp and synthetic fibers, a filament aggregate obtained by opening, if necessary, tows (fiber bundles) of synthetic fibers such as cellulose acetate can also be used. As for the fiber basis weight, when laminating cotton pulp or short fibers, for example, it can be set to about 100 to 300 g / m 2 and in the case of a filament aggregate, for example, it can be set to about 30 to 120 g / m 2 . In the case of synthetic fibers, the fineness is, for example, 1 to 16 dtex, preferably 1 to 10 dtex, and more preferably 1 to 5 dtex. In the case of a filament aggregate, the filaments may be non-crimped fibers, but are preferably crimped fibers. The crimp degree of the crimped fibers can be, for example, 5 to 75 per 2.54 cm, preferably 10 to 50, and more preferably about 15 to 50. Also, uniformly crimped crimped fibers can be used.

[0030] (Superabsorbent polymer particles) The absorber 56 can contain superabsorbent polymer particles in part or all of it. Superabsorbent polymer particles include "powders" in addition to "particles". As superabsorbent polymer particles, those used in this type of absorbent article can be used as they are. The particle size of the superabsorbent polymer particles is not particularly limited, but for example, sieving (shaking for 5 minutes) using a 500 μm standard sieve (JIS Z8801-1:2006), and sieving (shaking for 5 minutes) of the particles that fall through this sieve using a 180 μm standard sieve (JIS Z8801-1:2006), when the ratio of the particles remaining on the 500 μm standard sieve is 30% by weight or less and the ratio of the particles remaining on the 180 μm standard sieve is 60% by weight or more, is desirable.

[0031] As the material of the superabsorbent polymer particles, it can be used without particular limitation, but those with a water absorption of 30 g / g or more are preferred. Examples of the superabsorbent polymer particles include those based on starch, cellulose, and synthetic polymers, and those such as starch-acrylic acid (salt) graft copolymers, saponified products of starch-acrylonitrile copolymers, cross-linked products of sodium carboxymethyl cellulose, and acrylic acid (salt) polymers can be used. As the shape of the superabsorbent polymer particles, the commonly used powdery or granular form is preferred, but other shapes can also be used.

[0032] As the superabsorbent polymer particles, those with a water absorption rate of 70 seconds or less, particularly 40 seconds or less, are preferably used. If the water absorption rate is too slow, so-called reverse flow, in which the liquid supplied into the absorber 56 flows back out of the absorber 56, is likely to occur.

[0033] Also, as the superabsorbent polymer particles, those with a gel strength of 1000 Pa or more are preferably used. Thereby, even when the absorber 56 is bulky, the sticky feeling after liquid absorption can be effectively suppressed.

[0034] The basis weight of the superabsorbent polymer particles can be appropriately determined according to the absorption amount required for the use of the absorber 56. Therefore, although it cannot be generally stated, it can be set to 50 to 350 g / m 2 If the basis weight of the polymer is less than 50 g / m 2 , it becomes difficult to ensure the absorption amount. If it exceeds 350 g / m 2 , not only does the effect saturate, but an excessive amount of superabsorbent polymer particles gives a gritty and uncomfortable feeling.

[0035] (Packaging sheet) To prevent the superabsorbent polymer particles from leaking out or to enhance the shape retention of the absorber 56, the absorber 56 can be incorporated as an absorption element 50 wrapped with a packaging sheet 58. As the packaging sheet 58, tissue paper, especially crepe paper, non-woven fabric, poly-laminated non-woven fabric, a sheet with small holes, etc. can be used. However, a sheet that prevents the superabsorbent polymer particles from leaking out is desirable. When using a non-woven fabric instead of crepe paper, a hydrophilic SMMS (spunbond / meltblown / meltblown / spunbond) non-woven fabric is particularly suitable, and its material can be polypropylene, polyethylene / polypropylene, etc. The basis weight of the fiber is 5~40g / m 2 , particularly 10~30g / m 2 is desirable.

[0036] As shown in FIG. 3, this packaging sheet 58 may be in the form of wrapping the entire absorber 56 with a single sheet, or may wrap the entire absorber 56 with a plurality of sheets such as two upper and lower sheets. 。 The packaging sheet 58 can also be omitted.

[0037] (Top Sheet) The top sheet 30 has liquid permeability. For example, a porous or non-porous non-woven fabric, a porous plastic sheet, etc. can be used. Among them, for the non-woven fabric, the raw material fiber thereof is not particularly limited. For example, synthetic fibers such as olefin-based such as polyethylene and polypropylene, polyester-based, polyamide-based, etc., regenerated fibers such as rayon and cupra, natural fibers such as cotton, etc., and mixed fibers and composite fibers in which two or more of these are used can be exemplified. Furthermore, the non-woven fabric may be manufactured by any processing method. Examples of the processing method include known methods such as the spunlace method, the spunbond method, the thermal bond method, the meltblown method, the needle punch method, the air-through method, the point bond method, etc. For example, if flexibility and drapability are required, the spunlace method is a preferable processing method, and if bulkiness and softness are required, the thermal bond method is a preferable processing method.

[0038] The top sheet 30 extends from the front end to the rear end of the product in the longitudinal direction and extends laterally beyond the absorber 56 in the width direction WD. However, for example, when the starting point of the rising gathers 60 described later is located more toward the center in the width direction than the side edge of the absorber 56, the width of the top sheet 30 can be appropriately deformed, such as being made shorter than the full width of the absorber 56, as necessary.

[0039] (Intermediate sheet) In order to quickly transfer the liquid that has passed through the top sheet 30 to the absorber, an intermediate sheet (also called the "second sheet") 40 with a higher liquid permeation rate than the top sheet 30 can be provided. This intermediate sheet 40 is for quickly transferring the liquid to the absorber to enhance the absorption performance of the absorber and preventing the "backflow" phenomenon of the absorbed liquid from the absorber. The intermediate sheet 40 can also be omitted.

[0040] Examples of the intermediate sheet 40 include the same material as the top sheet 30, spunlace nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, pulp nonwoven fabric, a mixed sheet of pulp and rayon, point-bond nonwoven fabric, or crepe paper. In particular, an air-through nonwoven fabric is preferred because it is bulky. It is preferable to use composite fibers with a core-sheath structure for the air-through nonwoven fabric. In this case, the resin used for the core can be polypropylene (PP), but polyester (PET) with high rigidity is preferred. The basis weight is preferably 17~80 g / m 2 and more preferably 25~60 g / m 2 . The fineness of the raw material fibers of the nonwoven fabric is preferably 2.0~10 dtex. In order to make the nonwoven fabric bulky, it is also preferable to use eccentric fibers without a core in the center, hollow fibers, or eccentric and hollow fibers as all or part of the mixed fibers of the raw material fibers.

[0041] In the illustrated example, the intermediate sheet 40 is arranged shorter than the width of the absorber 56 and at the center, but it may be provided over the entire width. Also, the intermediate sheet 40 may be provided over the entire length of the diaper, or it may be provided only in the intermediate portion including the excretion position as in the illustrated example.

[0042] (Liquid-impermeable resin film) The liquid-impermeable resin film 11 is not particularly limited as long as it has moisture permeability. For example, an inorganic filler is kneaded into an olefin resin such as polyethylene or polypropylene, and after forming a sheet, a microporous sheet obtained by stretching in the uniaxial or biaxial direction can be preferably used. Needless to say, the liquid-impermeable resin film 11 does not include a non-woven fabric as a base material with enhanced waterproofing properties.

[0043] The liquid-impermeable resin film 11 desirably extends over the same or a wider range as the absorber 56 in the longitudinal direction LD and the width direction WD. However, when other water-blocking means are present, etc., it can also be in a form that does not cover the ends of the absorber 56 in the longitudinal direction LD and the width direction WD as necessary.

[0044] (Outer packaging non-woven fabric) The outer packaging non-woven fabric 12 covers the entire back side of the liquid-impermeable resin film 11 and gives the outer surface of the product the appearance of cloth. The outer packaging non-woven fabric 12 is not particularly limited. As the material fibers, for example, synthetic fibers such as olefin-based fibers such as polyethylene or polypropylene, polyester-based fibers, polyamide-based fibers, etc., as well as regenerated fibers such as rayon and cupra, and natural fibers such as cotton can be used. As the processing method, a spunlace method, a spunbond method, a thermal bond method, an air-through method, a needle punch method, etc. can be used. However, long fiber non-woven fabrics such as spunbond non-woven fabrics, SMS non-woven fabrics, and SMMS non-woven fabrics are preferable in terms of achieving both a good touch and strength. The non-woven fabric can be used alone or in multiple layers. In the latter case, it is preferable to bond the non-woven fabrics to each other with a hot melt adhesive or the like. When using a non-woven fabric, its basis weight is 10~50 g / m 2 , particularly preferably 15~30 g / m 2 is desirable.

[0045] The outer packaging non-woven fabric 12 can be bonded to an adjacent member on the front side, that is, in the case of the illustrated example, the liquid-impermeable resin film 11 and the moisture-absorbing sheet 15 described later, by an adhesive such as a hot melt adhesive applied in an appropriate pattern or by welding of the material.

[0046] (Raised gather) In order to prevent excrement from moving laterally along the topsheet 30 and to prevent so-called lateral leakage, it is preferable that raised gathers 60 that stand up on the wearer's skin side are provided on both sides in the width direction WD of the surface. Of course, the raised gathers 60 can also be omitted.

[0047] When the raised gathers 60 are adopted, the structure thereof is not particularly limited, and any known structure can be adopted. The raised gathers 60 in the illustrated example are composed of a gather sheet 62 that is substantially continuous in the width direction WD and an elongated gather elastic member 63 that is fixed to the gather sheet 62 in an extended state along the longitudinal direction LD. As the gather sheet 62, a water-repellent nonwoven fabric can be used, and as the gather elastic member 63, thread rubber or the like can be used. The elastic members can be provided in plural numbers as shown in FIGS. 1 and 2, or one elastic member can be provided for each.

[0048] The inner surface of the gather sheet 62 has a joining start end in the width direction WD on the side portion of the topsheet 30, and the portion outside the width direction from this joining start end is joined to the inner surfaces of the respective side flap portions SF, that is, the side portions of the liquid-impermeable resin film 11 and the side portions of the exterior nonwoven fabric 12 located outside the width direction thereof in the illustrated example by a hot melt adhesive or the like.

[0049] Around the legs, although the inner side in the width direction from the joining start end of the raised gathers 60 is fixed on the topsheet 30 at both front and rear ends in the product longitudinal direction, the intermediate portion is a non-fixed free portion, and this free portion rises due to the contraction force of the elastic member 63 and comes into close contact with the body surface.

[0050] (End flap portion, side flap portion) The illustrated tape-type disposable diaper has a pair of end flap portions EF without the absorber 56 extending respectively from the front side and the back side of the absorber 56, and a pair of side flap portions SF without the absorber 56 extending respectively laterally from both side edges of the absorber 56.

[0051] (Flat gathers) Each side flap portion SF is fixed with a side elastic member 64 made of an elongated elastic member such as a thread rubber in a state of being extended along the longitudinal direction LD, whereby the portion around the leg of each side flap portion SF is configured as flat gathers. side As shown in the illustrated example, the elastic member 64 can be provided between the gather sheet 62 and the liquid-impermeable resin film 11 on the outer side in the width direction near the start end of the joining portion of the gather sheet 62, and can also be provided between the liquid-impermeable resin film 11 and the outer packaging nonwoven fabric 12 in the side flap portion SF. side As shown in the illustrated example, a plurality of elastic members 64 can be provided on each side, or only one elastic member can be provided on each side.

[0052] (Connecting tape) Connecting tapes 13 are respectively provided on the side flap portions SF in the back side portion B so as to be detachably connected to the outer surface of the front side portion F. When wearing the diaper, the connecting tapes 13 are turned from both sides of the waist to the outer surface of the front side portion F, and the connecting portions 13A of the connecting tapes 13 are connected to appropriate positions on the outer surface of the front side portion F.

[0053] The structure of the connecting tape 13 is not particularly limited. In the illustrated example, it has a sheet base material forming a tape attachment portion 13C fixed to the side flap portion SF and a tape main body portion 13B protruding from the tape attachment portion 13C, and a connecting portion 13A for the front side provided at the middle portion in the width direction of the tape main body portion 13B in this sheet base material, and the tip side from this connecting portion 13A serves as a gripping portion.

[0054] As the connecting portion 13A, in addition to providing a hook material (male material) of a mechanical fastener (surface fastener), an adhesive layer may be provided. The hook material has a large number of engaging protrusions on its connecting surface, and as the shape of the engaging protrusions, there are (A) L-shaped, (B) J-shaped, (C) mushroom-shaped, (D) T-shaped, (E) double J-shaped (a shape formed by joining two J-shaped materials back to back), etc., and any shape may be used.

[0055] Also, as the sheet base material forming from the tape attachment portion 13C to the tape main body portion 13B, non-woven fabric, plastic film, poly-laminated non-woven fabric, paper, or a composite material thereof can be used, but a spunbond non-woven fabric, air-through non-woven fabric, or spunlace non-woven fabric with a fineness of 1.0 to 3.5 dtex, a basis weight of 20 to 100 g / m 2 , and a thickness of 1 mm or less is preferred.

[0056] (Target sheet) It is preferable to provide a target sheet 20 having a target for facilitating connection at the connection location of the connecting tape 13 in the ventral portion F. When the connecting portion 13A is a hook material, the target sheet 20 can be a sheet base material made of a plastic film or non-woven fabric with a large number of loop threads on its surface such that the engaging protrusions of the hook material are entangled. Also, in the case of an adhesive layer, a sheet base material made of a plastic film with a smooth surface rich in adhesiveness and subjected to a peeling treatment can be used. Further, when the connection location of the connecting tape 13 in the ventral portion F is made of non-woven fabric, for example, when having an exterior non-woven fabric 12 as in the illustrated form, the target sheet 20 can be omitted, and the hook material can be entangled with the fibers of the exterior non-woven fabric 12 for connection. In this case, the target sheet 20 as a mark may be provided between the exterior non-woven fabric 12 and the liquid-impermeable resin film 11.

[0057] (Moisture-absorbing sheet) Characteristically, as shown in FIGS. 8 to 10, a moisture-absorbing sheet 15 is provided between the liquid-impermeable resin film 11 and the outer nonwoven fabric 12. When such a moisture-absorbing sheet 15 is provided between the liquid-impermeable resin film 11 and the outer nonwoven fabric 12, moisture that has permeated through the liquid-impermeable resin film 11 is not blocked by the moisture-absorbing sheet 15, so the anti-sweating property during wearing is less likely to decrease. Nevertheless, due to the high moisture-absorbing property of the microfibrous cellulose aggregate, moisture is retained by the moisture-absorbing sheet 15 rather than by the outer nonwoven fabric 12 constituting the outer surface of the product or the undergarment, so the outer surface of the product and the undergarment are less likely to feel wet.

[0058] In particular, as shown in FIG. 11, it is preferable that the moisture-absorbing sheet 15 has a nonwoven fabric 16 in which thin portions 16t that have shrunk in the thickness direction are repeatedly formed at intervals, and a microfibrous cellulose aggregate 17 attached within the thin portions 16t. The thin portions 16t have depressions on both the front and back sides of the moisture-absorbing sheet 15 as in the illustrated example, or may have depressions on only one of the front and back sides of the moisture-absorbing sheet 15. Thereby, although the moisture-absorbing sheet 15 is sandwiched between the liquid-impermeable resin film 11 and the outer nonwoven fabric 12, a ventilation gap 18 is formed between them and the thin portions 16t of the moisture-absorbing sheet 15. Therefore, in this moisture-absorbing sheet 15, moisture can be released along the surface of the moisture-absorbing sheet 15 through this ventilation gap 18. Further, in the process, moisture can be efficiently supplied to the microfibrous cellulose aggregate 17, which is a moisture-absorbing material, and absorbed.

[0059] The moisture-absorbing sheet 15 may have the microfibrous cellulose aggregate 17 other than the thin portions 16t, but the microfibrous cellulose aggregate 17 is hard. Therefore, it is preferable that the microfibrous cellulose aggregate 17 is attached only to the thin portions 16t of the moisture-absorbing sheet 15. Thereby, the portion other than the thin portions 16t of the moisture-absorbing sheet 15 can be deformed flexibly, and it becomes difficult for the user or wearer to touch the hard thin portions 16t, or the hardness is less likely to be transmitted to the skin.

[0060] The thin portion 16t is not particularly limited as long as it is formed in a pattern that repeats at intervals. For example, as shown in FIG. 8, the thin portion 16t may be in a vertical stripe pattern in which a plurality of linear thin portions 16t along the longitudinal direction LD are arranged at intervals in the width direction WD, or as shown in FIG. 9, in a horizontal stripe pattern in which a plurality of linear thin portions 16t along the width direction WD are arranged at intervals in the longitudinal direction LD. Further, the thin portion 16t may be dot-shaped as shown in FIGS. 12(a) to (e), or may be obliquely lattice-shaped as shown in FIG. 12(f). In particular, when the thin portion 16t is provided in a stripe or lattice shape, the continuity of the ventilation gap 18 is increased. Therefore, it is preferable because it becomes even more excellent in breathability for releasing moisture and breathability for efficiently supplying moisture to the moisture absorbent. As described above, when the thin portion 16t is continuously formed linearly, it can be continuously formed not only linearly but also in a curved shape or a wavy shape.

[0061] The dimensions of the thin portion 16t can be determined as appropriate. When the arrangement of the thin portion 16t is a stripe pattern, the line width x1 of the thin portion 16t is preferably 1.0 to 4.0 mm, particularly preferably 2.0 to 3.0 mm, and the interval s1 between adjacent adhering portions is preferably 5 to 30 mm, particularly preferably 10 to 20 mm. Further, when the thin portion 16t is a dot pattern, the diameter d (length of the longest part) of the thin portion 16t is preferably 1.0 to 4.0 mm, particularly preferably 2.0 to 3.0 mm, and the center (or centroid) intervals s2 and s3 between adjacent rows in the width direction WD and the longitudinal direction LD are 5 to 25 mm, particularly 10~15 preferably mm. Further, when the arrangement of the thin portion 16t is a lattice pattern, the line width x2 of the thin portion 16t is preferably 1.0 to 4.0 mm, particularly preferably 2.0 to 3.0 mm, and the lattice interval s4 (interval between parallel thin portions 16t) is preferably 5 to 30 mm, particularly preferably 10 to 20 mm. The dimensions of the adhering portion of the microfibrous cellulose aggregate can be the same as, less than, or greater than the dimensions of the thin portion 16t.

[0062] The nonwoven fabric 16 constituting the moisture absorption sheet 15 is not particularly limited, but it is preferably bulky and has excellent formability. Therefore, the fineness is 2 to 10 dtex and the basis weight is 20 to 40 g / m2 It is preferably a short fiber nonwoven fabric.

[0063] To improve the hygroscopicity, the more the amount of microfibrous cellulose, the better, but if it is too much, the product will become unnecessarily hard. Therefore, the content of microfibrous cellulose in the thin portion 16t is 0.1 to 5.0 g / m 2 or so, particularly preferably 0.5 to 3.0 g / m 2 or so.

[0064] <Manufacturing method> For example, the moisture-absorbing sheet 15 can be manufactured by forming the thin portion 16t on the nonwoven fabric 16 that becomes the moisture-absorbing sheet 15 by embossing, or by attaching the microfibrous cellulose aggregate 17 to the thin portion 16t thereafter.

[0065] Also, the moisture-absorbing sheet 15 can be manufactured by the following method. That is, when a dispersion of microfibrous cellulose is applied to the nonwoven fabric 16 that becomes the moisture-absorbing sheet 15 in a pattern repeated at intervals, the dispersion penetrates between the fibers of the nonwoven fabric 16. And when this dries, a thin portion 16t is formed in the applied portion of the dispersion, and a microfibrous cellulose aggregate 17 is formed in the thin portion 16t. That is, after applying a dispersion of microfibrous cellulose to the nonwoven fabric 16 and drying the dispersion in the applied portion, when the microfibrous cellulose aggregate 17 is formed, the volume of the microfibrous cellulose aggregate 17 gradually decreases. Along with this, the volume of the applied portion of the dispersion on the nonwoven fabric 16 also decreases, and the thin portion 16t is automatically formed. This manufacturing method utilizes this. According to this method, the moisture-absorbing sheet 15 can be formed only by applying a dispersion of microfibrous cellulose to the nonwoven fabric 16 that becomes the moisture-absorbing sheet 15 in a desired pattern and drying it.

[0066] However, according to this manufacturing method, if another sheet is attached before drying (i.e., before the thin portion 16t is formed) after applying the dispersion liquid of microfibrous cellulose to the nonwoven fabric 16, the ventilation gap 18 may not be formed. Therefore, when attaching the present moisture-absorbing sheet 15 to another member, it is preferable to attach the other member after the formation of the thin portion 16t. For example, it is also possible in principle to form the thin portion 16t by applying the dispersion liquid of microfibrous cellulose to an existing nonwoven fabric 16 member such as the intermediate sheet 40 or the exterior nonwoven fabric 12. However, since it is necessary to attach another member after the dispersion liquid of microfibrous cellulose is dried, it is not suitable for manufacturing on a high-speed production line. Therefore, as shown in the illustrated example, it is preferable to separately manufacture a dedicated moisture-absorbing sheet 15 and attach it between appropriate members to manufacture a disposable wearable article. On the other hand, when forming the thin portion 16t by embossing, another member can be attached to the nonwoven fabric 16 that will become the moisture-absorbing sheet 15 before the dispersion liquid of microfibrous cellulose is applied.

[0067] When forming the adhering portion of the microfibrous cellulose aggregate 17 by applying the microfibrous cellulose dispersion liquid, the concentration (mass / volume) of the microfibrous cellulose dispersion liquid is preferably 0.1 to 10%, more preferably 1.0 to 5.0%, and particularly preferably 1.5 to 3.0%.

[0068] The B-type viscosity (60 rpm, 20 °C) of the microfibrous cellulose dispersion liquid is, for example, 700 cps or less, preferably 200 cps or less, and more preferably 50 cps or less. By suppressing the B-type viscosity of the microfibrous cellulose dispersion liquid in this way, the microfibrous cellulose can be uniformly applied to the nonwoven fabric.

[0069] The application of the microfibrous cellulose dispersion liquid can use a transfer method such as a relief printing method in addition to spraying on the target surface.

[0070] Examples of pulp fibers that can be used in the production of microfibrillar cellulose include chemical pulps such as hardwood pulp (LBKP) and softwood pulp (NBKP), bleached thermomechanical pulp (BTMP), stone ground pulp (SGP), pressurized ground pulp (PGW), refiner ground pulp (RGP), chemiground pulp (CGP), thermoground pulp (TGP), ground pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), refiner mechanical pulp (RMP), etc., waste paper such as tea waste paper, kraft envelopes old Paper, magazine waste paper, newspaper waste paper, flyer waste paper, office waste paper, cardboard waste paper, high-quality waste paper, Kent waste paper, imitation waste paper, deed waste paper, ledger waste paper, etc. can be used to produce waste paper pulp. Examples also include deinked pulp (DIP) obtained by deinking waste paper pulp. These can be used alone or in combination of multiple types as long as the intended effects are not impaired. Furthermore, those obtained by subjecting the above pulp fibers to chemical treatments such as carboxymethylation can also be used.

[0071] Examples of methods for producing microfibrillar cellulose include mechanical methods such as the high-pressure homogenizer method, microfluidizer method, grinder grinding method, bead mill cryogenic grinding method, ultrasonic fibrillation method, etc., but are not limited to these methods. Also, microfibrillation is promoted by the combined use of TEMPO oxidation treatment, phosphoric esterification treatment, acid treatment, etc.

[0072] <Others> The above moisture-absorbing sheet 15 can be used alone or attached to other parts of a disposable wearing article. When in use, a non-breathable member or a poorly breathable member may be adjacent to either one or both of the front and back sides of the moisture-absorbing sheet 15, or breathable materials may be adjacent to both the front and back sides, or there may be no member adjacent to either one side of the front and back.

[0073] For example, as shown in FIG. 9, a moisture-absorbing sheet 15 can be provided between members in the waist portion or the like, or as shown in FIG. 10, the moisture-absorbing sheet 15 can be provided on the back side of the target sheet 20 (for example, between the target sheet 20 and the outer nonwoven fabric 12, or between the outer nonwoven fabric 12 and the liquid-impermeable resin film 11).

[0074] In particular, in order to prevent stuffiness during wearing, if the moisture-absorbing sheet 15 is provided so as to have a portion adjacent to the back side of the breathable skin contact layer that contacts the skin of the wearer (the whole may be adjacent to the back side of the skin contact layer), moisture inside the disposable wearing article during wearing can be efficiently absorbed or released to the outside, thereby preventing stuffiness. For example, in the example shown in FIG. 9, when the moisture-absorbing sheet 15 is provided in the waist portion, the moisture-absorbing sheet 15 can be provided from between the absorber 56 and the liquid-impermeable resin film 11 to between the topsheet 30 and the liquid-impermeable resin film 11.

[0075] <Explanation of Terms in the Specification> The following terms in the specification have the following meanings unless otherwise specified in the specification.

[0076] · The "front-rear direction" means the direction indicated by the symbol LD in the figure (vertical direction), the "width direction" means the direction indicated by the symbol WD in the figure (left-right direction), and the front-rear direction and the width direction are orthogonal to each other.

[0077] · The "MD direction" and the "CD direction" mean the flow direction (MD direction) in the manufacturing equipment and the transverse direction (CD direction) orthogonal thereto. Depending on the part of the product, one of them becomes the front-rear direction and the other becomes the width direction. The MD direction of the nonwoven fabric is the direction of fiber orientation of the nonwoven fabric. Fiber orientation is the direction along which the fibers of the nonwoven fabric extend. For example, it can be determined by a measurement method according to the zero-distance tensile strength fiber orientation test method of TAPPI standard method T481 or a simple measurement method for determining the fiber orientation direction from the tensile strength ratio in the front-rear direction and the width direction.

[0078] · "Front side" means the side closer to the wearer's skin when worn, and "back side" means the side farther from the wearer's skin when worn.

[0079] · "Surface" means the side of the member closer to the wearer's skin when worn, and "back surface" means the side of the member farther from the wearer's skin when worn.

[0080] · "Elongation rate" means the value when the natural length is taken as 100%. For example, an elongation rate of 200% is synonymous with an elongation magnification of 2 times.

[0081] · "Gel strength" is measured as follows. Add 1.0 g of a superabsorbent polymer to 49.0 g of artificial urine (a mixture of urea: 2 wt%, sodium chloride: 0.8 wt%, calcium chloride dihydrate: 0.03 wt%, magnesium sulfate heptahydrate: 0.08 wt%, and ion-exchanged water: 97.09 wt%), and stir with a stirrer. After leaving the resulting gel in a thermo-hygrostat at 40°C and 60% RH for 3 hours, return it to room temperature, and measure the gel strength with a curd meter (manufactured by I.techno Engineering: Curdmeter-MAX ME-500).

[0082] · "Areal density" is measured as follows. After pre-drying the sample or test piece, leave it in a test chamber or apparatus under standard conditions (test location: temperature 23 ± 1°C, relative humidity 50 ± 2%) until it reaches a constant weight. Pre-drying means making the sample or test piece reach a constant weight in an environment at 100°C. For fibers with a moisture regain of 0.0%, pre-drying may not be necessary. Using a template for sample collection (100 mm × 100 mm), cut out a sample with dimensions of 100 mm × 100 mm from the test piece in a state of constant weight. Measure the weight of the sample, multiply it by 100, and calculate the weight per square meter, which is taken as the areal density.

[0083] · "Thickness" is measured using an automatic thickness measuring instrument (KES-G5 handy compression measurement program), with a load of 0.098 N / cm 2 and a pressurized area of 2 cm 2Automatically measure under the following conditions. The thickness of the perforated nonwoven fabric is measured at the part other than the holes and the protruding parts around them.

[0084] · The water absorption amount is measured according to JIS K7223-1996 "Test Method for Water Absorption Amount of Super Absorbent Resin".

[0085] · The water absorption rate is defined as the "time to the end point" when performing JIS K7224-1996 "Test Method for Water Absorption Rate of Super Absorbent Resin" using 2 g of superabsorbent polymer and 50 g of physiological saline.

[0086] "Microfibrous cellulose" refers to fine cellulose fibers or bundles thereof extracted from plants such as pulp, and generally refers to fibrous cellulose with an average fiber width in the nanosize range (1 to 1000 nm or less). Fibrous cellulose with an average fiber width (median diameter) of 100 nm or less (generally called cellulose nanofiber (CNF)) is preferred, and those with an average fiber width of 10 to 60 nm are particularly preferred.

[0087] The "average fiber width" of microfibrous cellulose can be measured by the following method. That is, first, 100 ml of an aqueous dispersion of microfibrous cellulose with a solid content concentration of 0.01 to 0.1 mass% is filtered through a Teflon (registered trademark) membrane filter, and the solvent is replaced once with 100 ml of ethanol and three times with 20 ml of t-butanol. Next, it is freeze-dried and osmium-coated to obtain a sample. For this sample, observation is performed by an SEM image of an electron microscope at any magnification of 5000 times, 10000 times, or 30000 times according to the width of the constituent fibers (in this example, a magnification of 30000 times). Specifically, draw two diagonal lines on the observation image, and arbitrarily draw three straight lines passing through the intersection of the diagonal lines. Further, a total of 100 fiber rods intersecting with these three straight lines are visually measured. Then, the median diameter (median diameter) of the measured values is taken as the average fiber width.

[0088] · The "unfolded state" means a state where it is unfolded flat without shrinkage or relaxation.

[0089] · Unless otherwise specified, the dimensions of each part refer to the dimensions in the unfolded state rather than the natural length state.

[0090] · In the case where there is no description of the environmental conditions in tests or measurements, such tests or measurements shall be conducted in a test chamber or within an apparatus under standard conditions (the test location shall be at a temperature of 23 ± 1°C and a relative humidity of 50 ± 2%).

Industrial Applicability

[0091] The present invention can be applied to disposable diapers in general, such as pant-type disposable diapers and pad-type disposable diapers in addition to the tape-type disposable diaper as in the above example, and it goes without saying that it can also be applied to other absorbent articles such as sanitary napkins.

Explanation of Reference Numerals

[0092] 11... Liquid-impermeable resin film, 12... Outer packaging non-woven fabric, 13... Connecting tape, 13A... Connecting part, 13B... Tape main body part, 13C... Tape attachment part, 15... Moisture-absorbing sheet, 16... Non-woven fabric, 16t... Thin part, 17... Micro-fibrous cellulose aggregate, 18... Gap, 20... Target sheet, 30... Top sheet, 40... Intermediate sheet, 50... Absorbing element, 56... Absorbent body, 58... Packaging sheet, 60... Rising gathers, 62... Gather sheet, B... Back side portion, F... Abdominal side portion, WD... Width direction, LD... Front-rear direction.

Claims

1. A moisture-absorbing sheet having a non-woven fabric in which thin portions contracted in the thickness direction are repeatedly formed at intervals, and a dried micro-fibrillar cellulose aggregate attached only to the fibers within the thin portions, wherein depressions of the thin portions are left without being filled on both the front and back sides of the moisture-absorbing sheet, The nonwoven fabric constituting the moisture-absorbing sheet is a short-fiber nonwoven fabric having a fineness of 2 to 10 dtex and a basis weight of 20 to 40 g / m ２ and The adhesion amount of the microfibrous cellulose aggregate in the thin part is 0.1 to 5.0 g / m ２ and characterized in that it is a moisture-absorbing sheet.

2. The moisture-absorbing sheet according to claim 1, wherein the micro-fibrillar cellulose aggregate is not present outside the thin portions.

3. The moisture-absorbing sheet according to claim 1 or 2, wherein the thin portions are provided in a striped or lattice pattern.

4. In a disposable wearing article having an absorber, a liquid-impermeable resin film having air permeability provided on the back side of the absorber, and an outer non-woven fabric covering the back surface of the liquid-impermeable resin film, the disposable wearing article having a moisture-absorbing sheet provided between the liquid-impermeable resin film and the outer non-woven fabric, wherein the moisture-absorbing sheet has a non-woven fabric in which thin portions contracted in the thickness direction are repeatedly formed at intervals, and a dried micro-fibrillar cellulose aggregate attached only to the fibers within the thin portions, wherein depressions of the thin portions are left without being filled on both the front and back sides of the moisture-absorbing sheet, and having air gaps between the outer non-woven fabric and the thin portions, and between the liquid-impermeable resin film and the thin portions, respectively, characterized in that it is a disposable wearing article.

5. A disposable wearing article having a breathable skin-contact layer that contacts the wearer's skin, and a moisture-absorbing sheet provided so as to have a portion adjacent to the back side of the skin-contact layer, wherein the moisture-absorbing sheet has a non-woven fabric in which thin portions contracted in the thickness direction are repeatedly formed at intervals, and a dried micro-fibrillar cellulose aggregate attached only to the fibers within the thin portions, wherein depressions of the thin portions are left without being filled on both the front and back sides of the moisture-absorbing sheet, and having air gaps between the skin-contact layer and the thin portions, and between a member adjacent to the back side of the moisture-absorbing sheet and the thin portions, respectively, characterized in that it is a disposable wearing article.

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13. A step of applying a dispersion liquid of microfibrous cellulose to a nonwoven fabric in a pattern that is repeated at intervals, and drying the dispersion liquid that has penetrated between the fibers of the nonwoven fabric, thereby forming a thin portion in the applied portion of the dispersion liquid, and adhering a dried microfibrous cellulose aggregate only to the fibers within the thin portion, and producing the moisture-absorbing sheet in which the depressions of the thin portions remain without being filled on both the front and back sides. A step of attaching the moisture-absorbing sheet in which the depressions of the thin portions remain without being filled on both the front and back sides between members that overlap in the thickness direction of a disposable wearing article, and producing a disposable wearing article having a ventilation gap between the member and the thin portion. A method for manufacturing a disposable wearing article, characterized by the above.

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