CN113518716A

CN113518716A - Absorbent sheet, disposable wearing article, and method for producing same

Info

Publication number: CN113518716A
Application number: CN202080018294.4A
Authority: CN
Inventors: 冈田友记; 古川勉
Original assignee: Daio Paper Corp
Current assignee: Daio Paper Corp
Priority date: 2019-03-22
Filing date: 2020-01-27
Publication date: 2021-10-19
Anticipated expiration: 2040-01-27
Also published as: TW202034881A; WO2020195096A1; JP2020151352A; CN113518716B; TWI805894B

Abstract

[ problem ] to provide a moisture-absorbing sheet having excellent air permeability for releasing moisture and air permeability for efficiently supplying moisture to a moisture-absorbing material, a disposable wearing article, and a method for manufacturing the same. [ solution ] the above object is achieved by a moisture-absorbing sheet (15), the moisture-absorbing sheet (15) comprising: a nonwoven fabric (16) in which thin sections (16t) that shrink in the thickness direction are repeatedly formed at intervals; and a microfibrous cellulose aggregate (17) attached to the inside of the thin-walled portion (16 t).

Description

Absorbent sheet, disposable wearing article, and method for producing same

Technical Field

The present invention relates to an absorbent sheet, a disposable wearing article, and a method for manufacturing the same.

Background

Disposable wearing articles such as disposable diapers and sanitary napkins have been proposed to have moisture absorption properties for various reasons.

For example, disposable wearing articles such as disposable diapers and sanitary napkins have an absorbent body that absorbs excretory fluid such as urine and a liquid impermeable resin film that covers the back side of the absorbent body, and materials having moisture permeability in the thickness direction have been used as the liquid impermeable resin film in order to prevent stuffiness when worn (see, for example, patent documents 1 and 2). In many absorbent articles, the back side of a liquid-impermeable resin film is covered with an outer-covering nonwoven fabric in order to give the outer surface of the article a cloth-like texture and appearance (see, for example, patent document 2).

However, in the conventional absorbent article, in order to prevent stuffiness, the liquid impermeable resin film has high moisture permeability and is damaged, and after the absorbent body absorbs the excretory fluid, the outer surface of the product or underwear retains moisture, and leakage may be mistakenly recognized when touched with a hand.

This problem can be solved by reducing the moisture permeability of the liquid-impermeable resin film, but in this case, reduction in the stuffy heat resistance cannot be avoided. Therefore, for example, it has been proposed to provide a moisture-absorbing layer on a liquid-impermeable resin film or an outer-covering nonwoven fabric (see, for example, patent document 1).

Further, it is known that disposable wearing articles are generally poor in breathability and therefore tend to be stuffy inside the disposable wearing article when worn, and in order to prevent this, it has been proposed to attach an absorbent sheet (see, for example, patent document 3).

Further, a moisture-absorbing sheet may be used as a product packaging material or in a product package (for example, see patent document 4).

However, the performance of the absorbent material is of course important for the absorbent sheet, and the air permeability for releasing moisture and the air permeability for supplying moisture to the absorbent material are also important.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6442098

Patent document 2: japanese patent laid-open publication No. 2017-144174

Patent document 3: japanese patent laid-open publication No. 2010-279621

Patent document 4: japanese laid-open patent publication No. 2010-279606

Disclosure of Invention

Problems to be solved by the invention

Accordingly, a main object of the present invention is to provide a moisture-absorbent sheet having excellent air permeability for releasing moisture and air permeability for efficiently supplying moisture to a moisture-absorbent material, a disposable wearing article, and a method for producing the same.

Means for solving the problems

The absorbent sheet and the like which solve the above problems are as follows.

< embodiment 1 >

An absorbent sheet characterized by having:

a nonwoven fabric in which thin-walled portions that contract in the thickness direction are repeatedly formed at intervals; and

and a microfibrous cellulose aggregate attached to the inside of the thin wall portion.

(Effect)

The absorbent sheet is characterized in that a microfibrous cellulose aggregate having high moisture absorption is adhered in a thin-walled portion based on a nonwoven fabric in which thin-walled portions are repeatedly formed at intervals. Therefore, even when the absorbent sheet of the present invention is used by being sandwiched between objects or members, an air-permeable gap is formed between the objects or members and the thin wall portion of the absorbent sheet. Therefore, in the present absorbent sheet, moisture can be released along the surface of the absorbent sheet through the air-permeable gap. In addition, in this process, moisture can be efficiently supplied to the microfibrous cellulose aggregates as the moisture absorbent material to be absorbed. Such an absorbent sheet can be used alone or can be made part of a disposable wearing article as described later.

< embodiment 2 >

The absorbent sheet according to claim 1, which does not have the microfibrous cellulose aggregate other than the thin portion.

(Effect)

The microfibrous cellulose aggregates are hard. Therefore, the absorbent sheet preferably has the microfibrous cellulose aggregate adhered only to the thin wall portion. This makes it possible to flexibly deform the portion of the absorbent sheet other than the thin portion, and makes it difficult for the user or wearer to touch the hard thin portion or to transmit the hardness to the skin.

< embodiment 3 >

The absorbent sheet according to

claim

1 or 2, wherein the thin portion is provided in a stripe or lattice shape.

(Effect)

When the thin portions are provided in a stripe or lattice shape, continuity of the air-permeable gap is improved. Therefore, the air permeability for releasing moisture and the air permeability for efficiently supplying moisture to the moisture absorbent material are more excellent.

< embodiment 4 >

The absorbent sheet according to

claim

1 or 2, wherein the nonwoven fabric constituting the absorbent sheet has a fineness of 2 to 10dtex and a basis weight of 20 to 40g/m²The short-fiber non-woven fabric of (2),

the attachment amount of the microfibrous cellulose aggregates in the thin-walled part is 0.1 to 5.0g/m²。

(Effect)

The nonwoven fabric constituting the absorbent sheet is not particularly limited, but is preferably bulky and excellent in shaping properties, and therefore, a nonwoven fabric within the above range is preferable. In addition, in order to improve the moisture absorption, the more the amount of the microfibrous cellulose aggregates attached, the better, but if too much, the product may become unnecessarily hard. Therefore, the content of the microfibrous cellulose aggregates in the thin-walled portion is preferably within the above range.

< embodiment 5 >

A disposable wearing article having:

an absorbent body;

a liquid-impermeable resin film that is provided on the back side of the absorbent body and has air permeability; and

an outer nonwoven fabric covering the back surface of the liquid-impermeable resin film,

the disposable wearing article is characterized in that,

has a moisture-absorbing sheet provided between the liquid-impermeable resin film and the outer-covering nonwoven fabric,

the absorbent sheet comprises: a nonwoven fabric in which thin-walled portions that contract in the thickness direction are repeatedly formed at intervals; and a microfibrous cellulose aggregate attached to the inside of the thin wall portion,

air permeable gaps are provided between the outer nonwoven fabric and the thin portion, and between the liquid impermeable resin film and the thin portion.

(Effect)

In the disposable wearing article of the present invention, the absorbent sheet of the 1 st aspect is interposed between the liquid-impermeable resin film and the outer-covering nonwoven fabric to form an air-permeable gap. Therefore, according to the disposable wearing article of the present invention, the moisture absorption sheet can effectively absorb moisture discharged from the liquid impermeable resin film, which is increased after absorbing the discharged liquid, and the outer surface of the product or the underwear hardly has a wet touch.

< embodiment 6 >

A disposable wearing article characterized by comprising:

a skin-contacting layer which is in contact with the skin of the wearer and is breathable; and

a moisture-absorbing sheet disposed in such a manner as to have a portion adjacent to the back side of the skin-contact layer,

an air-permeable gap is provided between the skin contact layer and the thin portion.

(Effect)

In order to prevent stuffiness when worn, the disposable wearing article is provided with an absorbent sheet so as to have a portion adjacent to the back side of the skin contact layer. This can effectively absorb moisture in the interior of the disposable wearing article when worn, or release moisture to the outside, thereby preventing stuffiness.

< 7 th mode >

A method for manufacturing a disposable wearing article, comprising the steps of:

a step of applying a dispersion of microfibrous cellulose to a nonwoven fabric in a repeating pattern at intervals and drying the dispersion to produce a moisture-absorbing sheet having a thin portion formed on the applied portion of the dispersion and microfibrous cellulose aggregates formed on the thin portion; and

and a step of manufacturing a disposable wearing article having an air-permeable gap between the member and the thin portion by attaching the absorbent sheet between the members overlapped in the thickness direction of the disposable wearing article.

(Effect)

When the dispersion of the microfibrous cellulose is applied to a nonwoven fabric and then the applied portion of the dispersion is dried, the volume of the microfibrous cellulose aggregates gradually decreases when the microfibrous cellulose aggregates are formed. In addition, the volume of the portion of the nonwoven fabric to which the dispersion is applied is also reduced, and the thin portion is automatically formed. The present manufacturing method takes advantage of this.

For example, a thin portion may be formed on a nonwoven fabric to be a moisture-absorbing sheet by embossing, and at the same time or after, the microfibrous cellulose aggregates may be attached to the thin portion.

Further, when the liquid dispersion of the microfibrous cellulose is applied to a nonwoven fabric and then adhered to another member of a disposable wearing article before drying (i.e., before forming a thin portion), there is a possibility that the formation of the air-permeable gap is insufficient. In contrast, in the present manufacturing method, since the disposable wearing article is manufactured using the dried absorbent sheet, a good air-permeable gap can be formed. Therefore, in the present manufacturing method, the cover layer is attached after the thin portion is formed.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there are advantages such as excellent air permeability for releasing moisture and excellent air permeability for efficiently supplying moisture to the moisture absorbent material.

Drawings

Fig. 1 is a plan view showing the inner surface of a tape-type disposable diaper in a state where the diaper is unfolded.

Fig. 2 is a plan view showing the outer surface of the tape-type disposable diaper in a state where the diaper is unfolded.

Fig. 3 is a cross-sectional view taken along line 6-6 of fig. 1.

Fig. 4 is a cross-sectional view taken along line 7-7 of fig. 1.

Fig. 5 is a cross-sectional view taken along line 8-8 of fig. 1.

Fig. 6 is a cross-sectional view taken along line 9-9 of fig. 1.

Fig. 7 is a cross-sectional view taken along line 5-5 of fig. 1.

Fig. 8 is a plan view showing a state where the diaper is unfolded in the main part.

Fig. 9 is a plan view showing a state where the diaper is unfolded in the main part.

Fig. 10 is a plan view showing a state where the diaper is unfolded in the main part.

Fig. 11 is an enlarged cross-sectional view of the absorbent sheet.

Fig. 12 is a plan view showing various patterns of the thin-walled portions (attachment portions of microfibrous cellulose).

Detailed Description

Fig. 1 to 7 show an example of a tape-type disposable diaper, in which reference numeral W denotes the entire width of the diaper except for a connecting tape, reference numeral L denotes the entire length of the diaper, dot pattern portions in sectional views denote adhesives as joining means for joining the respective constituent members located on the front and back sides thereof, and the adhesive is formed by full-surface application, droplet application, curtain application, Summit application, spiral application, pattern application (transfer of a hot-melt adhesive in a relief form) or the like of a hot-melt adhesive, or a fixed portion of an elastic member is formed by application to the outer peripheral surface of the elastic member by an application gun (comb gun) or SureWrap application or the like instead of or together with the adhesive. Examples of the hot melt adhesive include adhesives of EVA type, adhesive rubber type (elastomer type), olefin type, polyester/polyamide type, and the like, and can be used without particular limitation. As a joining means for joining the respective components, a means based on fusion of raw materials such as heat sealing and ultrasonic sealing may be employed.

The tape-type disposable diaper comprises: an absorber 56; a liquid-permeable top sheet 30 covering the front side of the absorber 56; a liquid-impermeable resin film 11 that covers the back side of the absorber 56; and an outer-covering nonwoven fabric 12 which covers the back side of the liquid-impermeable resin film 11 and constitutes the outer surface of the product. Reference numeral F denotes a ventral portion located more anteriorly than the anteroposterior direction center, and reference numeral B denotes a dorsal portion located more posteriorly than the anteroposterior direction center.

The materials and characteristics of each part will be described in turn below.

(absorber)

The absorber 56 is a part that absorbs and holds excretory fluid, and may be formed of an aggregate of fibers. As the fiber aggregate, a fiber aggregate obtained by stacking short fibers such as cotton pulp or synthetic fibers, and a filament aggregate obtained by opening a tow (fiber bundle) of synthetic fibers such as cellulose acetate as necessary may be used. The basis weight of the fibers may be, for example, 100 to 300g/m in the case of stacking cotton pulp or short fibers²On the other hand, in the case of the filament aggregate, for example, it may be 30 to 120g/m²Left and right. The fineness of the synthetic fiber is, for example, 1 to 16dtex, preferably 1 to 10dtex, and more preferably 1 to 5 dtex. In the case of filament aggregates, the filaments may also be non-crimped fibers, but preferably crimped fibers. With respect to the degree of crimp of crimped fibers, for example,the number of the cells per 2.54cm may be 5 to 75, preferably 10 to 50, and more preferably 15 to 50. In addition, uniformly crimped fibers may be used.

(superabsorbent polymer particles)

The absorbent body 56 may contain superabsorbent polymer particles in a part or all thereof. The super absorbent polymer particles include "powder" in addition to "particles". As the super absorbent polymer particles, super absorbent polymer particles used in such absorbent articles can be directly used. The particle size of the super absorbent polymer particles is not particularly limited, and for example, the following particle sizes are preferable: when the particles falling to the undersize by the sieving were sieved (5 minutes shaking) using a 500 μm standard sieve (JIS Z8801-1:2006), and the particles were sieved (5 minutes shaking) using a 180 μm standard sieve (JIS Z8801-1:2006), the proportion of the particles remaining on the 500 μm standard sieve was 30 wt% or less, and the proportion of the particles remaining on the 180 μm standard sieve was 60 wt% or more.

The material of the super absorbent polymer particles is not particularly limited, but is preferably a material having a water absorption capacity of 30g/g or more. As the super absorbent polymer particles, there are starch-based, cellulose-based, synthetic polymer-based and the like, and starch-acrylic acid (salt) graft copolymer, saponified product of starch-acrylonitrile copolymer, crosslinked product of sodium carboxymethylcellulose, acrylic acid (salt) polymer and the like can be used. The shape of the super absorbent polymer particles is preferably a normally used powder-like super absorbent polymer particle, but super absorbent polymer particles of other shapes may be used.

As the super absorbent polymer particles, super absorbent polymer particles having a water absorption rate of 70 seconds or less, particularly 40 seconds or less are preferably used. When the water absorption rate is too low, so-called back flow, in which the liquid supplied into the absorbent body 56 is returned to the outside of the absorbent body 56, is likely to occur.

In addition, as the super absorbent polymer particles, it is preferable to use super absorbent polymer particles having a gel strength of 1000Pa or more. This can effectively suppress the sticky feeling after liquid absorption even when the absorbent body 56 is formed to be bulky.

The basis weight of the super absorbent polymer particles may be determined as appropriate depending on the absorption amount required for the use of the absorbent body 56. Therefore, it can be 50 to 350g/m². The basis weight of the polymer is less than 50g/m²In this case, it is difficult to ensure the absorption amount. More than 350g/m²In the case of the super absorbent polymer particles, the effect is saturated, and the super absorbent polymer particles are excessively contained, so that the particles are uncomfortable.

(packaging sheet)

The absorbent body 56 may be incorporated as an absorbent unit 50 wrapped with a wrapping sheet 58 in order to prevent the superabsorbent polymer particles from coming off or to improve the shape retention of the absorbent body 56. As the wrapping sheet 58, a paper towel, in particular, crepe paper, nonwoven fabric, polyethylene laminated nonwoven fabric, a sheet with small holes, or the like can be used. Among them, a sheet in which the super absorbent polymer particles are not separated is preferable. When a nonwoven fabric is used instead of crepe paper, a hydrophilic SMMS (spunbond/meltblown/spunbond) nonwoven fabric is particularly preferable, and polypropylene, polyethylene/polypropylene, or the like can be used as the material. The basis weight of the fiber is preferably 5 to 40g/m²Particularly preferably 10 to 30g/m²。

The packaging sheet 58 may be configured such that the entire absorbent body 56 is wrapped with one sheet as shown in fig. 3, or the entire absorbent body 56 may be wrapped with a plurality of sheets such as upper and lower 2 sheets. The wrapping sheet 58 may be omitted.

(Top sheet)

The top sheet 30 has liquid permeability, and for example, a nonwoven fabric or a porous plastic sheet having holes or holes may be used. The type of the raw material fibers of the nonwoven fabric is not particularly limited. Examples thereof include synthetic fibers such as olefin-based, polyester-based, and polyamide-based fibers, e.g., polyethylene and polypropylene; regenerated fibers such as rayon and cuprammonium fibers; natural fibers such as cotton, and mixed fibers and composite fibers using two or more of these fibers. The nonwoven fabric may be produced by any process. Examples of the processing method include known methods such as a spunlace method, a spunbond method, a thermal bond method, a melt blowing method, a needle punching method, a hot air method, and a point bonding method. For example, if flexibility and drapability are required, the spunlace method is a preferred processing method, and if bulkiness and flexibility are required, the thermal bonding method is a preferred processing method.

The top sheet 30 extends from the front end to the rear end of the product in the front-rear direction and extends to a position more lateral than the absorbent body 56 in the width direction WD, but in the case where the starting points of the standing gathers 60 described later are located more toward the widthwise center side than the side edges of the absorbent body 56, for example, appropriate deformation such as making the width of the top sheet 30 shorter than the full width of the absorbent body 56 can be performed as necessary.

(intermediate sheet)

In order to rapidly transfer the liquid having passed through the top sheet 30 to the absorbent member, an intermediate sheet (also referred to as "second sheet") 40 having a liquid passing speed higher than that of the top sheet 30 may be provided. The intermediate sheet 40 is used to transfer liquid quickly into the absorbent body, to improve the absorption performance of the absorbent body, and to prevent the phenomenon of "back flow" of the absorbed liquid from the absorbent body. The intermediate sheet 40 may also be omitted.

The intermediate sheet 40 may be made of the same material as the top sheet 30, or a spun lace nonwoven fabric, a spun bond nonwoven fabric, an SMS nonwoven fabric, a pulp nonwoven fabric, a mixed sheet of pulp and rayon, a point-bonded nonwoven fabric, or a crepe paper. In particular, a through-air nonwoven fabric is preferable because it is bulky. In the case where the composite fiber having a core-sheath structure is preferably used for the air-through nonwoven fabric, the resin used for the core may be polypropylene (PP), but Polyester (PET) having high rigidity is preferable. The basis weight of the fiber is preferably 17-80 g/m²More preferably 25 to 60g/m². The thickness of the raw material fiber of the nonwoven fabric is preferably 2.0 to 10 dtex. In order to make the nonwoven fabric bulky, it is also preferable to use a fiber having a core which is not centered, a hollow fiber, or a fiber having a core which is eccentric and hollow as a mixed fiber of all or a part of the raw material fibers.

The intermediate sheet 40 in the illustrated example is shorter than the width of the absorber 56 and is disposed at the center, but the intermediate sheet 40 may be provided over the entire width. The intermediate sheet 40 may be provided over the entire length of the diaper, but may be provided only in the intermediate portion including the excretion portion as shown in the illustrated example.

(liquid-impermeable resin film)

The liquid-impermeable resin film 11 is not particularly limited as long as it has moisture permeability, and for example, a microporous sheet obtained by kneading an inorganic filler with an olefin resin such as polyethylene or polypropylene, molding the resultant sheet, and then stretching the sheet in a uniaxial or biaxial direction can be suitably used. Of course, the liquid-impermeable resin film 11 does not include a material having improved water repellency using a nonwoven fabric as a base material.

The liquid-impermeable resin film 11 preferably extends in the same or a wider range as the absorbent body 56 in the front-back direction LD and the width direction WD, and may be set in a form not covering the end of the absorbent body 56 in the front-back direction LD and the width direction WD as necessary when other water blocking means are present.

(nonwoven fabric for exterior application)

The outer non-woven fabric 12 covers the entire back side of the liquid-impermeable resin film 11, and gives the outer surface of the product a cloth-like appearance. The outer-covering nonwoven fabric 12 is not particularly limited, and examples of the raw material fibers include synthetic fibers such as olefin-based fibers, polyester-based fibers, and polyamide-based fibers, such as polyethylene and polypropylene, regenerated fibers such as rayon and cuprammonium fibers, and natural fibers such as cotton, and the processing method may include spunlace, spunbond, thermal bond, air-through, needle-punching, and the like. Among them, long fiber nonwoven fabrics such as spun bond nonwoven fabrics, SMS nonwoven fabrics, SMMS nonwoven fabrics and the like are preferable from the viewpoint of satisfying both the touch feeling and the strength. Instead of using one nonwoven fabric, a plurality of nonwoven fabrics may be used in a stacked state. In the latter case, the nonwoven fabrics are preferably bonded to each other with a hot melt adhesive or the like. When a nonwoven fabric is used, the basis weight of the fiber is preferably 10 to 50g/m²Particularly preferably 15 to 30g/m²。

The outer-covering nonwoven fabric 12 may be bonded to a member adjacent to the front side, that is, in the case of the illustrated example, to the liquid-impermeable resin film 11 or the absorbent sheet 15, which will be described later, by an adhesive such as a hot-melt adhesive applied in an appropriate pattern or by fusion bonding of raw materials.

(vertical pleats)

In order to prevent the excrement moving in the transverse direction along the top sheet 30 and to prevent so-called side leakage, it is preferable that standing gathers 60 standing up toward the skin of the wearer are provided on both sides in the width direction WD of the surface. Of course, the standing gather 60 may be omitted.

When the standing gather 60 is used, the structure thereof is not particularly limited, and any known structure can be used. The raised gathers 60 illustrated in the drawing are composed of a gather sheet 62 substantially continuous in the width direction WD, and an elongated gather elastic member 63 fixed to the gather sheet 62 in an extended state along the front-rear direction LD. As the gather sheet 62, a water repellent nonwoven fabric can be used, and as the gather elastic member 63, a rubber thread or the like can be used. Instead of providing a plurality of elastic members as shown in fig. 1 and 2, 1 elastic member may be provided.

The inner surface of the gather sheet 62 has a joining start end in the width direction WD on the side portion of the top sheet 30, and a portion on the outer side in the width direction from the joining start end is joined to the inner surface of each side flap portion SF, that is, the side portion of the liquid impermeable resin film 11 and the side portion of the outer-covering nonwoven fabric 12 on the outer side in the width direction in the illustrated example, by a hot melt adhesive or the like.

In the leg hole, the portion further to the inner side in the width direction than the joining start end of the standing gather 60 is fixed to the top sheet 30 at both ends in the front-rear direction of the product, but the portion therebetween is an unfixed free portion which stands up by the contraction force of the elastic member 63 and comes into close contact with the body surface.

(wing part, flank part)

The tape-type disposable diaper illustrated in the drawings has a pair of end flaps EF extending to the front side and the rear side of the absorbent body 56, respectively, and not having the absorbent body 56, and a pair of side flaps SF extending laterally from both side edges of the absorbent body 56, respectively, and not having the absorbent body 56.

(plane pleat)

A side elastic member 64 made of an elongated elastic member such as a rubber thread is fixed to each side flap portion SF in an extended state along the front-rear direction LD, and thus the leg hole portion of each side flap portion SF is configured as a planar gather. The side elastic member 64 may be provided between the gather sheet 62 and the liquid-impermeable resin film 11 on the outer side in the width direction in the vicinity of the joining start end of the gather sheet 62 in the joined portion as shown in the drawing, or between the liquid-impermeable resin film 11 and the outer-covering nonwoven fabric 12 in the flap portion SF. The side elastic members 64 may be provided in a plurality of numbers on each side as shown in the illustrated example, or may be provided in a number of only 1 on each side.

(connecting belt)

The side wing portions SF in the back portion B are provided with connecting bands 13, respectively, and the connecting bands 13 are detachably connected to the outer surface of the stomach portion F. When the diaper is worn, the connecting belt 13 is wound around the outer surface of the abdominal portion F from both sides of the waist, and the connecting portion 13A of the connecting belt 13 is connected to an appropriate position on the outer surface of the abdominal portion F.

The structure of the connecting belt 13 is not particularly limited, and in the illustrated example, the connecting belt includes: a sheet base material having a tape mounting portion 13C fixed to the wing portion SF and a tape main body portion 13B protruding from the tape mounting portion 13C; and a connecting portion 13A provided at a widthwise intermediate portion of the belt main body portion 13B in the sheet base material and connected to the abdomen side, and a portion on the distal end side of the connecting portion 13A serves as a grip portion.

The coupling portion 13A may be provided with an adhesive layer in addition to hook members (convex members) of a mechanical fastener (surface fastener). The hook member has a plurality of engaging projections on its coupling surface, and the engaging projections may have any shape, such as (a) レ shape, (B) J shape, (C) mushroom shape, (D) T shape, (E) double J shape (shape in which the J-shaped engaging projections are coupled back to back).

The sheet base material from the belt mounting portion 13C to the belt body portion 13B may be a nonwoven fabric, a plastic film, a polyethylene laminated nonwoven fabric, paper, or a composite material thereof, and preferably has a fineness of 1.0 to 3.5dtex and a basis weight of 20 to 100g/m²Spun-bonded nonwoven fabric, hot-air nonwoven fabric, or spun-laced nonwoven fabric having a thickness of 1mm or less.

(target sheet)

The target sheet 20 having a target for facilitating the joining is preferably provided at the joining portion of the joining band 13 in the abdominal portion F. As the target sheet 20, in the case where the coupling portion 13A is a hook member, a target sheet in which a large number of loop yarns around which the engaging protrusions of the hook member are to be wound are provided on the surface of a sheet base material made of a plastic film or a nonwoven fabric may be used, and in the case of an adhesive layer, a target sheet in which a peeling treatment is applied to the surface of a sheet base material made of a plastic film having a smooth surface and high adhesiveness may be used. In the case where the connecting portion of the connecting band 13 in the stomach-side portion F is formed of a nonwoven fabric, for example, in the case where the exterior nonwoven fabric 12 is provided as in the illustrated example, the target sheet 20 may be omitted and the hook member may be wound around the fiber of the exterior nonwoven fabric 12 to connect the two. In this case, the target sheet 20 may be provided as a mark between the outer nonwoven fabric 12 and the liquid-impermeable resin film 11.

(moisture-absorbing sheet)

Characteristically, as shown in fig. 8 to 10, a moisture-absorbing sheet 15 is provided between the liquid-impermeable resin film 11 and the outer-covering nonwoven fabric 12. When such a moisture-absorbing sheet 15 is provided between the liquid-impermeable resin film 11 and the outer-covering nonwoven fabric 12, moisture that has passed through the liquid-impermeable resin film 11 is not blocked by the moisture-absorbing sheet 15, and thus the stuffiness resistance during wearing is not easily reduced. Even so, due to the high hygroscopicity of the microfibrous cellulose aggregates, moisture is held in the moisture-absorbing sheet 15 as compared with the outer-covering nonwoven fabric 12 or underwear constituting the outer surface of the product, and therefore the outer surface of the product or the underwear is less likely to develop a moist touch.

In particular, as shown in fig. 11, the absorbent sheet 15 preferably has: a nonwoven fabric 16 in which thin portions 16t that shrink in the thickness direction are repeatedly formed at intervals; and a microfibrous cellulose aggregate 17 attached inside the thin-walled portion 16 t. The thin portion 16t may have a depression only on either the front-side back side of the absorbent sheet 15, in addition to the depressions on both the front-side back side of the absorbent sheet 15 as in the illustrated example. Thus, the absorbent sheet 15 is sandwiched between the liquid-impermeable resin film 11 and the outer-covering nonwoven fabric 12, but an air-permeable gap 18 is formed between the absorbent sheet 15 and the thin portion 16 t. Therefore, in the present absorbent sheet 15, moisture can be released along the surface of the absorbent sheet 15 through the air-permeable gaps 18. In this process, moisture can be efficiently supplied to the microfibrous cellulose aggregates 17 as the moisture absorbent material to absorb moisture.

The absorbent sheet 15 may have the microfibrous cellulose aggregate 17 in addition to the thin portion 16t, but the microfibrous cellulose aggregate 17 is hard. Therefore, the absorbent sheet 15 preferably has the microfibrous cellulose aggregate 17 adhered only to the thin portion 16 t. This makes it possible to flexibly deform the portion of the absorbent sheet 15 other than the thin portion 16t, and makes it difficult for the user or wearer to touch the hard thin portion 16t or to transmit the hardness thereof to the skin.

The thin portions 16t may be formed in a repeating pattern at intervals, and the pattern thereof is not particularly limited. For example, the thin portion 16t may be in the form of a vertical stripe in which a plurality of linear thin portions 16t extending in the front-rear direction LD are arranged at intervals in the width direction WD as shown in fig. 8, or may be in the form of a horizontal stripe in which a plurality of linear thin portions 16t extending in the width direction WD are arranged at intervals in the front-rear direction LD as shown in fig. 9. The thin portion 16t may be in a dot shape as shown in fig. 12(a) to (e), or may be in a cross-hatched shape as shown in fig. 12 (f). In particular, when the thin portions 16t are provided in a stripe or lattice shape, the continuity of the air-permeable gap 18 is improved. Therefore, air permeability for releasing moisture and air permeability for efficiently supplying moisture to the moisture absorbent material are more excellent, and thus preferable. When the thin portion 16t is continued linearly in this manner, it may be continued linearly, or may be continued in a curved or wavy line.

The size of the thin-walled portion 16t may be determined as appropriate. When the thin portions 16t are arranged in a stripe pattern, the line width x1 of the thin portions 16t is preferably 1.0 to 4.0mm, particularly preferably 2.0 to 3.0mm, and the interval s1 between adjacent adhering portions is preferably 5 to 30mm, particularly preferably 10 to 20 mm. When the thin portions 16t are in a dot pattern, the diameter d (the length of the longest portion) of the thin portions 16t is preferably 1.0 to 4.0mm, and particularly preferably 2.0 to 3.0mm, and the distances s2 and s3 between the centers (or centers of gravity) of adjacent rows in the width direction WD and the front-rear direction LD are preferably 5 to 25mm, and particularly preferably 10 to 15 mm. When the thin portions 16t are arranged in a lattice pattern, the line width x2 of the thin portions 16t is preferably 1.0 to 4.0mm, particularly preferably 2.0 to 3.0mm, and the lattice spacing s4 (the spacing between the parallel thin portions 16t) is preferably 5 to 30mm, particularly preferably 10 to 20 mm. The attachment portion of the microfibrous cellulose aggregate may have the same size as that of the thin-walled portion 16t, or smaller or larger than that of the thin-walled portion 16 t.

The nonwoven fabric 16 constituting the absorbent sheet 15 is not particularly limited, but is preferably bulky and excellent in shaping properties, and therefore, the nonwoven fabric has a fineness of 2 to 10dtex and a basis weight of 20 to 40g/m²The short fiber nonwoven fabric of (1).

In order to improve the moisture absorption, the more the amount of the microfibrous cellulose, the better, but if too much, the product may be unnecessarily hardened. Therefore, the content of the microfibrous cellulose in the thin portion 16t is preferably 0.1 to 5.0g/m²About, particularly preferably 0.5 to 3.0g/m²Left and right.

< production method >

For example, the absorbent sheet 15 can be manufactured by forming the thin portion 16t on the nonwoven fabric 16 to be the absorbent sheet 15 by embossing, and simultaneously or subsequently attaching the microfibrous cellulose aggregate 17 to the thin portion 16 t.

The absorbent sheet 15 can be manufactured by the following method. That is, when the dispersion of the microfibrous cellulose is applied to the nonwoven fabric 16 serving as the absorbent sheet 15 in a repeating pattern at intervals, the dispersion penetrates into the spaces between the fibers of the nonwoven fabric 16. Then, upon drying thereof, the thin-walled portion 16t is formed in the applied portion of the dispersion liquid, and at the same time, the microfibrous cellulose aggregates 17 are formed in the thin-walled portion 16 t. That is, when the dispersion of the microfibrous cellulose is applied to the nonwoven fabric 16 and then the applied portion of the dispersion is dried, the volume of the microfibrous cellulose aggregate 17 gradually decreases when the microfibrous cellulose aggregate 17 is formed. In addition, the volume of the portion of the nonwoven fabric 16 to which the dispersion is applied is reduced, and the thin portion 16t is automatically formed. The present manufacturing method takes advantage of this. According to this method, the moisture-absorbent sheet 15 can be formed simply by applying the dispersion of the microfibrous cellulose to the nonwoven fabric 16 to be the moisture-absorbent sheet 15 in a desired pattern and drying the same.

However, according to this manufacturing method, after the dispersion of the microfibrous cellulose is applied to the nonwoven fabric 16, if another sheet is attached before drying (i.e., before the thin portion 16t is formed), the air-permeable gap 18 may not be formed. Therefore, when the present absorbent sheet 15 is attached to another member, it is preferable to attach another member after the thin portion 16t is formed. For example, the thin portion 16t can be formed in principle by applying a dispersion of microfibrous cellulose to a conventional nonwoven fabric 16 member such as the intermediate sheet 40 or the outer-cover nonwoven fabric 12. However, since it is necessary to attach other members to the microfibrous cellulose dispersion after drying, it is not suitable for production in a high-speed production line. Therefore, as in the illustrated example, it is preferable to manufacture a disposable wearing article by separately manufacturing a dedicated absorbent sheet 15 and fitting it between appropriate members. In contrast, when the thin portion 16t is formed by embossing, another member may be bonded to the nonwoven fabric 16 to be the absorbent sheet 15 before the liquid dispersion of the microfibrous cellulose is applied.

When the attachment portions of the microfibrous cellulose aggregates 17 are formed by coating the microfibrous cellulose dispersion, the concentration (mass/volume) of the microfibrous cellulose dispersion is preferably 0.1 to 10%, more preferably 1.0 to 5.0%, and particularly preferably 1.5 to 3.0%.

The B-type viscosity (60rpm, 20 ℃) of the microfibrous cellulose dispersion is, for example, 700cps or less, preferably 200cps or less, and more preferably 50cps or less. By suppressing the B-type viscosity of the microfibrous cellulose dispersion liquid so low, the microfibrous cellulose is uniformly imparted to the nonwoven fabric.

The microfibrous cellulose dispersion may be applied by a transfer method such as a relief printing method, in addition to spraying on the target surface.

Examples of pulp fibers that can be used for the production of the microfibrous cellulose include chemical pulps such as hardwood pulp (LBKP) and softwood pulp (NBKP), bleached thermomechanical pulp (BTMP), ground wood pulp (SGP), pressure ground wood Pulp (PGW), refined ground wood pulp (RGP), chemical ground wood pulp (CGP), high-temperature ground wood pulp (TGP), ground wood pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), and mechanical pulp (RMP); waste paper pulp produced from tea waste paper, kraft envelope waste paper, magazine waste paper, newspaper waste paper, leaflet waste paper, office waste paper, corrugated paper waste paper, high-white waste paper, kent waste paper, imitation waste paper, securities waste paper, grass paper waste paper, etc.; deinked pulp (DIP) obtained by deinking waste paper pulp, and the like. These pulps may be used alone or in combination of two or more kinds as long as the target effect is not impaired. Further, a material obtained by subjecting the pulp fiber to chemical treatment such as carboxymethylation may be used.

Examples of the method for producing the microfibrous cellulose include mechanical methods such as a high-pressure homogenizer method, a high-pressure microfluidizer method, a mill grinding method, a bead mill freeze-pulverization method, and an ultrasonic defibration method, but are not limited to these methods. In addition, microfibrillation is promoted by oxidation treatment with TEMPO, phosphorylation treatment, acid treatment, and the like in combination.

< others >

The absorbent sheet 15 may be used alone or may be attached to other parts of the disposable wearing article. In use, the non-breathable member or the hardly breathable member may be adjacent to either or both of the front and back sides of the absorbent sheet 15, the breathable material may be adjacent to both of the front and back sides, or no member adjacent to either of the front and back sides may be present.

For example, as shown in fig. 9, the absorbent sheet 15 may be provided between members at the waist or the like, or as shown in fig. 10, the absorbent sheet 15 may be provided on the back side of the target sheet 20 (for example, between the target sheet 20 and the outer-covering nonwoven fabric 12, or between the outer-covering nonwoven fabric 12 and the liquid-impermeable resin film 11).

In particular, when the absorbent 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) in order to prevent stuffiness during wearing, moisture in the interior of the disposable wearing article during wearing can be effectively absorbed or released to the outside, and stuffiness can be prevented. For example, in the example shown in fig. 9, in the case where the absorbent sheet 15 is provided at the waist portion, the absorbent sheet 15 may be provided from between the absorbent body 56 and the liquid-impermeable resin film 11 to between the topsheet 30 and the liquid-impermeable resin film 11.

< description of terms in the specification >

Unless otherwise specified in the specification, the following terms in the specification have the following meanings.

"front-rear direction" means a direction (longitudinal direction) indicated by reference numeral LD in the drawing, "width direction" means a direction (left-right direction) indicated by WD in the drawing, and the front-rear direction is orthogonal to the width direction.

"MD direction" and "CD direction" refer to a flow direction (MD direction) in a manufacturing apparatus and a transverse direction (CD direction) orthogonal to the flow direction, and depending on a part of a product, either one is a front-back direction and the other is a width direction. The MD direction of a nonwoven fabric is the direction in which the fibers of the nonwoven fabric are oriented. The fiber orientation is a direction along which the fibers of the nonwoven fabric are oriented, and can be determined by, for example, a measurement method according to a fiber orientation test method of zero-distance tensile strength by TAPPI standard method T481, or a simple measurement method of determining the fiber orientation direction from the tensile strength ratio in the front-back direction and the width direction.

"front side" refers to the side that is closer to the wearer's skin when worn, and "back side" refers to the side that is further from the wearer's skin when worn.

"surface" refers to the side of the component that is closer to the wearer's skin when worn, and "back" refers to the side of the component that is further from the wearer's skin when worn.

"elongation" means a value when the natural length is 100%. For example, an elongation of 200% has the same meaning as an elongation magnification of 2 times.

"gel strength" was determined as follows. 49.0g of a super absorbent polymer was added to 49.0g of artificial urine (prepared by mixing 2 wt% of urea, 0.8 wt% of sodium chloride, 0.03 wt% of calcium chloride dihydrate, 0.08 wt% of magnesium sulfate heptahydrate, and 97.09 wt% of ion-exchanged water), and the mixture was stirred with a stirrer. The resultant gel was allowed to stand in a constant temperature and humidity bath at 40 ℃ X60% RH for 3 hours, and then returned to normal temperature, and the gel strength was measured by a curdometer-MAX ME-500 (manufactured by I.techno Engineering Co.).

"basis weight" is determined as follows. After the sample or test piece was preliminarily dried, it was placed in a laboratory or apparatus in a standard state (temperature at the test site was 23. + -. 1 ℃ and relative humidity was 50. + -. 2%) so as to be in a state of constant volume. Pre-drying refers to bringing the sample or test strip to a constant level in an environment at a temperature of 100 ℃. The fibers having a official moisture regain of 0.0% may not be subjected to preliminary drying. A100 mm X100 mm-sized sample was cut out from a test piece which had reached a constant weight state using a template (stencil) for sample collection (100mm X100 mm). The weight of the sample was measured and multiplied by 100 to calculate the weight per 1 square meter as the basis weight.

"thickness" using an automatic thickness tester (KES-G5 portable compression tester), under load: 0.098N/cm²And a pressing area: 2cm²Under the conditions of (1) automatically. The thickness of the perforated nonwoven fabric was measured at the portions other than the holes and the projections around the holes.

The water absorption was measured in accordance with JIS K7223-1996 "method for testing the Water absorption of a super absorbent resin".

Water absorption Rate the "time to end point" in the "Water absorption Rate test method for highly Water-absorbent resin" of JIS K7224-1996 was carried out using 2g of a highly Water-absorbent Polymer and 50g of physiological saline.

"microfibrous cellulose" refers to a fine cellulose fiber or a bundle thereof taken out of a plant such as pulp, and generally refers to a fibrous cellulose having an average fiber width of nanometer size (1 to 1000nm), preferably a cellulose having an average fiber width (median diameter) of 100nm or less (generally referred to as Cellulose Nanofibril (CNF)), and particularly preferably a cellulose having an average fiber width of 10 to 60 nm.

The "average fiber width" of the microfibrous cellulose can be determined by the following method. Specifically, 100ml of an aqueous dispersion of microfibrous cellulose having a solid content concentration of 0.01 to 0.1 mass% was filtered through a teflon (registered trademark) membrane filter, and 1 solvent substitution was performed with 100ml of ethanol and 3 solvent substitutions were performed with 20ml of t-butanol. Subsequently, freeze-drying was performed, and osmium was applied to the sample. The sample was observed at any of 5000 times, 10000 times, or 30000 times (in the present example, 30000 times) according to the width of the fiber to be formed, based on the SEM image of the electron microscope. Specifically, two diagonal lines are drawn in the observation image, and three straight lines passing through the intersections of the diagonal lines are arbitrarily drawn. Further, a total of 100 fiber rods crossing the three straight lines were visually measured. And, the median diameter (mean diameter) of the measured values was taken as the average fiber width.

"expanded state" refers to a state of flat expansion without contraction or relaxation.

Unless otherwise specified, the dimensions of each part are dimensions in the expanded state, not in the natural length state.

The test or measurement is carried out in a laboratory or apparatus in a standard state (the temperature at the test site is 23 ± 1 ℃, and the relative humidity is 50 ± 2%) without description of the environmental conditions in the test or measurement.

Industrial applicability

The present invention can be applied to all types of disposable diapers such as pants-type disposable diapers and pad-type disposable diapers, as well as to other absorbent articles such as sanitary napkins, as well as to tape-type disposable diapers as in the above examples.

Description of the reference symbols

11 … liquid-impermeable resin film, 12 … outer nonwoven fabric, 13 … joining tape, 13a … joining section, 13B … tape main body section, 13C … tape mounting section, 15 … moisture-absorbing sheet, 16 … nonwoven fabric, 16t … thin-wall section, 17 … microfibrous cellulose aggregate, 18 … gap, 20 … target sheet, 30 … top sheet, 40 … intermediate sheet, 50 … absorbing unit, 56 … absorber, 58 … wrapping sheet, 60 … standing gather, 62 … pleated sheet, B … back side section, F … belly side section, WD … width direction, LD … front-back direction.

Claims

1. An absorbent sheet characterized by having:

a microfibrous cellulose aggregate adhered within the thin-walled portion.

2. The absorbent sheet according to claim 1, wherein the microfibrous cellulose aggregates are absent except for the thin-walled portion.

3. The absorbent sheet according to claim 1 or 2, wherein the thin-walled portion is provided in a stripe or lattice shape.

4. The absorbent sheet according to claim 1 or 2,

the nonwoven fabric constituting the absorbent sheet has a fineness of 2dtex to 10dtex and a basis weight of 20g/m²～40g/m²The short-fiber non-woven fabric of (2),

the attachment amount of the microfibrous cellulose aggregates in the thin wall part was 0.1g/m²～5.0g/m²。

5. A disposable wearing article having:

an absorbent body;

an outer-covering nonwoven fabric covering the back surface of the liquid-impermeable resin film,

the disposable wearing article is characterized in that,

the absorbent sheet has: a nonwoven fabric in which thin-walled portions that contract in the thickness direction are repeatedly formed at intervals; and microfibrous cellulose aggregates attached within the thin-walled portion,

air permeable gaps are provided between the outer-covering nonwoven fabric and the thin portion, and between the liquid impermeable resin film and the thin portion.

6. A disposable wearing article characterized by comprising:

an air-permeable gap is provided between the skin contact layer and the thin-walled portion.

7. A method for manufacturing a disposable wearing article, comprising the steps of:

and a step of manufacturing a disposable wearing article having an air-permeable gap between the member and the thin-walled portion by attaching the absorbent sheet between the members overlapped in the thickness direction of the disposable wearing article.