RU2771691C2 - Absorbent product - Google Patents

Abstract

FIELD: absorbent products.

SUBSTANCE: invention relates to absorbent products. The effect is achieved by an absorbent article including an absorbent material 56 and a liquid-impermeable polymeric film 11 covering the outside of the absorbent material 56, in which a layer 15 of cellulosic nanofibers is attached directly to the element outside the liquid-impermeable polymeric film 11, and a layer 15 of cellulose nanofibers can come into contact with the odor in the atmosphere outside the absorbent article.

EFFECT: invention increases the effectiveness of the contact between the deodorant and the odor.

5 cl, 12 dwg

Description

The field of technology to which the invention belongs

[0001]

The present invention relates to an absorbent article, such as a disposable diaper, including a pant-type diaper and a band-type diaper or sanitary napkin.

State of the art

[0002]

In general, an absorbent article such as a disposable diaper or sanitary napkin is applied in such a form that the absorbent article is wrapped or folded so that the body exudate sticking surface is on the inside after use, placed in a highly sealed storage container, such as a sanitary box or container for storage of diapers for temporary storage, and placed in a trash bag and discarded when the amount in the container reaches a certain level. After use, the absorbent article emits a strong smell of body exudates, which creates discomfort to the user. Therefore, in order to reduce the odor of body exudates after use, it is proposed to place a deodorant sheet containing zeolite inside the top sheet (Patent Document 1), include a deodorant in a crepe paper wrapping an absorbent material (Patent Document 2), and the like.

Bibliography

Patent Documents

[0003]

Patent Document 1: JP 2001-046423 A

Patent Document 2: JP 2000-350745A

Patent Document 3: JP 4236117 B2

Patent Document 4: JP 4652387 B2

The essence of the invention

Technical problem

[0004]

However, since a conventional solid deodorant does not itself have an adhesive ability, in order to securely fix the deodorant to the absorbent article, it is necessary to use a fixing agent such as a hot melt adhesive or a pressure-sensitive adhesive. In this case, in addition to the disadvantage of increasing the cost of the fixing agent, there is also the disadvantage that the deodorant particles are completely or partially covered with the fixing agent, which reduces the effectiveness of the contact of the deodorant particles with the smell.

[0005]

Therefore, the main purpose of the present invention is to improve the effectiveness of the contact between the deodorant substance and the smell.

Solution

[0006]

Various aspects of an absorbent article that has solved the above problems are as follows.

<Invention according to Claim 1>

An absorbent article comprising:

absorbent material; and

a liquid-impervious polymeric film covering the outer side of the absorbent material, while

a layer of cellulose nanofibers is attached directly to the element on the outside of the liquid-impervious polymer film, and

the layer of cellulose nanofibers can come into contact with the odor in the atmosphere outside the absorbent article.

[0007]

(Action and effect)

The inventor of the present invention has made careful studies to solve the above problem, and has found that the cellulose nanofiber layer has sufficient adhesiveness by itself and produces an odor physical adsorption effect to reduce odor. The present invention is based on the above findings. In accordance with the present invention, the cellulosic nanofiber layer is attached directly to the element from the outside of the liquid-impermeable polymer film (meaning that the cellulosic nanofiber layer is attached to the element only due to the adhesive ability of the cellulose nanofibers, without the use of adhesive or the like, as described below in text), and the layer of cellulose nanofibers can come into contact with the odor in the atmosphere outside the absorbent article. Therefore, the cellulosic nanofiber layer has a high odor contact efficiency, and the odor outside the absorbent article, in particular the odor inside the storage container, when the absorbent article is temporarily stored in the storage container, can be reduced more effectively. It should be noted that each of Patent Documents 3 and 4 describes an invention related to applying cellulose nanofibers to an absorbent article, but not for the purpose of reducing odor.

[0008]

<Invention according to Claim 2>

An absorbent article according to claim 1, including an outer nonwoven material covering the outer surface of a liquid-impervious polymeric film, wherein

a layer of cellulose nanofibers is sandwiched between the liquid-impermeable polymeric film and the outer nonwoven fabric, and

the outer nonwoven material has a fiber fineness of 1.0-6.0 dtex, a fiber density of 15-45 g/m ² and a thickness of 0.5-3.0 mm.

[0009]

(Action and effect)

The area containing the layer of cellulose nanofibers is inevitably hard, and the outer surface of the absorbent article may have a hard texture. Therefore, as described above, it is desirable to hinder the stiffness transfer of the cellulosic nanofiber layer in order to reduce deterioration in the texture of the outer surface of the absorbent article by coating the cellulosic nanofiber layer with a relatively hard and dense outer nonwoven material.

[0010]

<Invention according to Claim 3>

Absorbent article according to claim 1 or 2, including:

a ventral side portion located anteriorly from the center in the anterior-posterior direction, and a dorsal side portion located posteriorly from the center in the anterior-posterior direction; and

a disposal tape protruding from both side portions of the dorsal side portion or protruding from an intermediate portion in the transverse direction of the dorsal side portion, wherein

the cellulosic nanofiber layer is located on the dorsal side portion, and the cellulosic nanofiber layer is not located on the ventral side portion.

[0011]

(Action and effect)

For the absorbent article, a form in which the disposal tape is attached to the outer surface of the absorbent article in a rolled and folded state is widely used so that the inner surface of the absorbent article is the inner side at the time of disposal. In such a discarding state, as shown in FIG. 12, the outer surface of the absorbent article is covered by the backside portion, and the odor generated by body exudates adhering to the inner surface of the absorbent article or by body exudates absorbed by the absorbent material is emitted to the outside through the backside portion of the outer surface. Therefore, when the cellulosic nanofiber layer is disposed in the back side portion, the cellulosic nanofiber layer is disposed in the main odor path of the waste mold into which the absorbent article is folded or folded, and therefore, the odor reducing effect is more pronounced. In addition, in the form for disposal in which the absorbent article is rolled or folded, the layer of cellulose nanofibers is located closer to the outer surface. Therefore, the odor reducing effect is also exhibited in relation to the odor existing outside the article, for example, the odor in the storage container. In addition, with such a configuration, the odor reducing effect is successfully exhibited without arranging the cellulosic nanofiber layer all over the outside of the liquid-impermeable resin film, and hence the cost efficiency is also high.

[0012]

<Invention According to Claim 4>

An absorbent article according to any one of paragraphs. 1-3, in which

the cellulosic nanofiber layer is located only in the region where the cellulosic nanofiber layer is overlaid by the absorbent material.

[0013]

(Action and effect)

The area containing the layer of cellulose nanofibers is inevitably rigid. On the user's skin side, the stiffness of the cellulosic nanofiber layer is masked by the softening action of the absorbent material in the region where the cellulosic nanofiber layer is overlaid by the absorbent material. However, in a non-absorbent area, stiffness cannot be expected to be hidden by the absorbent material. Therefore, it is desirable to position the cellulosic nanofiber layer only in the region where the cellulosic nanofiber layer is overlapped by the absorbent material.

[0014]

<Invention According to Claim 5>

An absorbent article according to any one of paragraphs. 1-4, which includes an outer nonwoven material covering the outer surface of a liquid-impermeable polymer film, while

layers of cellulose nanofibers are located between the liquid-impermeable polymer film and the outer non-woven material in a plurality of positions at intervals in at least one of the front-to-back direction and the transverse direction and are attached directly to at least the liquid-impervious polymer film,

the liquid-impervious polymeric film is bonded to the outer nonwoven fabric at a site free of cellulose nanofiber layers with a hot melt adhesive, and

some or all of each of the cellulose nanofiber layers is not coated with a hot melt adhesive.

[0015]

(Action and effect)

Considering the adhesiveness of the cellulosic nanofiber layer, its odor contact efficiency, and the texture of the outer surface, it is desirable to attach the cellulosic nanofiber layer to the outer surface of the liquid-impermeable polymer film and cover its outer surface with an outer nonwoven fabric. Here, the outer nonwoven material is usually bonded to the liquid-impermeable polymeric film by means of a hot melt adhesive. However, coating the cellulose nanofiber layer with a hot-melt adhesive is not desirable from the viewpoint of improving the contact efficiency between the cellulose nanofiber layer and the odor. On the contrary, as described above, when a structure is formed in which layers of cellulosic nanofibers are arranged at a plurality of positions at intervals, the liquid-impervious resin film is bonded to the outer nonwoven fabric at a given interval portion, and part or all of each of the layers of cellulosic nanofibers is not covered. hot-melt adhesive, the decrease in contact efficiency between each of the layers of cellulosic nanofibers and odor can be reduced if the outer nonwoven material is bonded to a liquid-impermeable polymer film, which is desirable.

In addition, the layer of cellulose nanofibers is rigid. Therefore, when the layer of cellulose nanofibers is continuously arranged over a wide area, the softness of the product may deteriorate. On the contrary, when the layers of cellulosic nanofibers are arranged at intervals, the reduction in softness can be reduced if the layers of cellulosic nanofibers are arranged in a wide area. In addition, cellulose nanofibers absorb odor through physical adsorption. Cellulosic nanofibers are fine fibers and therefore have a high relative elongation and a relatively large specific surface area. Therefore, the cellulosic nanofibers have a higher physical adsorption capacity than conventional deodorant particles, and therefore provide a strong odor reducing effect even if the layers of the cellulosic nanofibers are spaced. In addition, the amount of cellulose nanofibers used can be reduced and hence the cost effectiveness is also very significant.

[0016]

<Invention According to Claim 6>

An absorbent article according to any one of paragraphs. 1-5, in which

the cellulose nanofibers of the cellulose nanofiber layer have an average fiber width of 10-100 nm, and

the layer of cellulose nanofibers includes 0.1-5.0 g/m ^{2 of} cellulose nanofibers.

[0017]

(Action and effect)

The average fiber width of the cellulose nanofibers and the amount used are not particularly limited, but are preferably within the above range in the ordinary case.

Useful effects of the invention

[0018]

The present invention provides an absorbent article having improved contact efficiency between an odor control agent and an odor.

Brief description of the drawings

[0019]

Fig. 1 is a plan view showing an inner surface of a band-type disposable diaper in a state in which the diaper is unfolded.

Fig. 2 is a plan view showing an outer surface of the tape-type disposable diaper in a state in which the diaper is unfolded, and showing an area for applying a layer of cellulose nanofibers.

Fig. 3 is a section through 6-6 in FIG. one.

Fig. 4 is a section through 7-7 in FIG. one.

Fig. 5 is a section through 8-8 in FIG. one.

Fig. 6 is a section through 9-9 in FIG. one.

Fig. 7 is a section through 5-5 in FIG. one.

Fig. 8 is a sectional view showing the main body.

Fig. 9 is a section showing the main body.

Fig. 10 is a section showing the main body.

Fig. 11 is a plan view showing an outer surface of the tape-type disposable diaper in a state in which the diaper is unfolded, and showing an area for applying a layer of cellulose nanofibers.

Fig. 12 is an explanatory diagram showing a state in which the disposable diaper is discarded.

Description of Embodiments

[0020]

After excretion of waste products by the user, the band-type diaper is rolled up so that the body waste cannot be seen from the outside, and discarded. As an example of how to dispose of a band-type diaper, the diaper is folded in the dorso-abdominal direction so that the inner surface of the diaper is the inner side to form a substantially cylindrical shape (disposal mold) (see Fig. 12( a)). Thus, even if the body exudates are rolled into a substantially cylindrical shape, the odor of the body exudates spreads out of the substantially cylindrical shape. Therefore, a diaper with improved contact efficiency between a deodorant and odor is provided below.

[0021]

Fig. 1-7 show an example of a band-type disposable diaper. Symbol X in the drawings indicates the maximum width of the diaper, without the connecting tape. The symbol L indicates the maximum length of the diaper. The dotted section in the sections depicts the adhesive as an adhesive for connecting the constituent elements located on the side of the inner surface and the outer surface. The constituent elements are formed by applying the hot melt adhesive by continuous application, dot application, shower application, Summit nozzle application, spiral application, screen application (hot melt adhesive transfer by letterpress printing method), or the like. Alternatively, instead of or in addition to this, the fixing portion of the elastic element is formed by applying to the outer peripheral surface of the elastic element with a combination gun, SureWrap nozzle, or the like. Examples of the hot melt adhesive include ethylene-vinyl acetate (EVA) adhesive, rubber-containing pressure-sensitive adhesive (elastomer-based adhesive), polyolefin-based adhesive, and polyester/polyamide adhesive, and these adhesives can be used without special restrictions. Material welding, such as heat sealing or ultrasonic welding, can also be used as an adhesive agent for connecting constituent elements.

[0022]

This band-type disposable diaper includes an absorbent material 56, a liquid-pervious topsheet 30 covering the inner surface of the absorbent material 56, a liquid-impermeable polymeric film 11 covering the outer surface of the absorbent material 56, and an outer nonwoven material 12 covering the outer surface of the impervious material. for liquid polymer film and forming the outer surface of the product. Symbol F denotes the area of the ventral side, located on the front side of the center in the anterior-posterior direction. Symbol B denotes a portion of the dorsal side, located on the dorsal side from the center in the anterior-posterior direction.

[0023]

Further in the text, the material of each section and its characteristic part will be sequentially described.

(absorbent material)

The absorbent material 56 absorbs and retains bodily fluid and may be formed from a collection of fibers. In this collection of fibers, in addition to fibers obtained from a set of short fibers, such as fluff pulp or synthetic fibers, it is also possible to use, if necessary, a collection of elementary fibers obtained by opening a tow (fiber bundle) of synthetic fibers, for example, from cellulose acetate. In the case where fluff pulp or short fibers are collected, the density of the fibers may be, for example, approximately 100-300 g/m ² . In the case of a plurality of filaments, the density of the fibers, the density of the fibers may be, for example, approximately 30-120 g/m ² . In the case of a synthetic fiber, the fineness is, for example, 1-16 dtex, preferably 1-10 dtex and more preferably 1-5 dtex. In the case of a plurality of filaments, the filaments may be formed as non crimped fibers, but are preferably formed as crimped fibers. The degree of crimp of the crimped fibers may be, for example, about 5-75, preferably 10-50, and more preferably 15-50 per inch (2.54 cm). In addition, evenly crimped fibers can be used.

[0024]

(Superabsorbent polymer particles)

The absorbent material 56 may contain some or all of the superabsorbent polymer particles. Superabsorbent polymer particles include "powder" in addition to "particles". As the superabsorbent polymer particles 54, the particles used for this type of absorbent article can be used as is. The particle diameters of the superabsorbent polymer particles are not specifically limited. However, for example, when a sieve separation is performed using a 500 µm standard sieve (JIS Z8801-1: 2006) (shaking for five minutes), and particles falling through the sieve using this separation are separated using a 180 µm standard sieve (JIS Z8801-1: 2006) (shaking for five minutes), it is desirable that the proportion of particles remaining on the 500 μm standard sieve is not more than 30% by weight, and the proportion of particles remaining on the 180 μm standard sieve , was not less than 60% by weight.

[0025]

The material of the superabsorbent polymer particles is not particularly limited, but materials with a water absorption capacity of at least 30 g/g are preferred. Examples of the superabsorbent polymer particles include starch-based material, cellulose-based material, and polymer-based synthetic material. A starch-acrylic acid graft (salt), a saponification product of a starch-acrylonitrile copolymer, a crosslinking product of sodium carboxymethyl cellulose, an acrylic acid polymer (its salts) or the like can be used. A suitable form of superabsorbent polymer particles is the form commonly used, but other forms may also be used.

[0026]

As superabsorbent polymer particles, particles having a water absorption rate of no more than 70 seconds, in particular no more than 40 seconds, are sufficiently suitable. When the rate of water absorption is too low, there is a tendency for the so-called return, when the liquid supplied to the absorbent material 56 is given off from the absorbent material 56.

[0027]

Suitable superabsorbent polymer particles are particles having a gel strength of at least 1000 Pa. This makes it possible to effectively eliminate the sticky feeling after liquid absorption, even in the case of using the high bulk absorbent material 56.

[0028]

The density of the superabsorbent polymer particles can be appropriately set depending on the absorbed volume required when applying the absorbent material 56. Therefore, the density can be 50-350 g/m ² although this requirement is not a rule. The density of the polymer below 50 g/m ² makes it difficult to fix the absorbed volume. When the density exceeds 350 g/m ² , not only does saturation occur, but an excess of superabsorbent polymer particles also creates a gritty and uncomfortable feeling.

[0029]

(Wrapping sheet)

The absorbent material 56 may be enclosed in the form of an absorbent member 50 wrapped in a wrap sheet 58 to prevent spillage of superabsorbent polymeric particles or to better support the shape of the absorbent material 56. The wrap sheet 58 may be tissue paper, in particular crepe paper, non-woven fabric, multi-layer nonwoven fabric, pinhole sheet, and the like. However, it is desirable that the wrap sheet 58 be a sheet from which the superabsorbent polymer particles do not escape. If a nonwoven material is used instead of crepe paper, a hydrophilic spunbond/meltblown/meltblown/spunbond (SMMS) composite nonwoven material is particularly suitable, and polypropylene, polyethylene/polypropylene or the like can be used as the material. Desirable is a non-woven fabric having a fiber density of 5-40 g/m ² , in particular 10-30 g/m ² .

[0030]

As shown in FIG. 3, a single wrap sheet 58 may enclose the entire absorbent material 56, or a plurality of wrap sheets 58, such as two wrap sheets 58, a top and a bottom, may enclose the entire absorbent material 56. In addition, the wrap sheet 58 may be omitted.

[0031]

(Top sheet)

The top sheet 30 may be a liquid-pervious sheet, such as a perforated or non-perforated nonwoven or porous plastic sheet. Of these materials, the nonwoven fabric is not specifically limited to the original fiber for it. Examples of raw fiber include synthetic fiber such as polyolefin fiber including polyethylene and polypropylene, polyester fiber or polyamide fiber, regenerated fiber such as viscose fiber or so-called cupra, natural fiber such as cotton , and a blended fiber and a composite fiber using at least two of these fibers. In addition, the nonwoven material can be produced by any technology. Examples of the manufacturing method include known methods such as the hydroentangling method, the spinning bonding method, the thermal bonding method, the meltblown method, the needle punched method, the air stuffing method, and the point bonding method. For example, if softness and drapeability are required, then the preferred manufacturing method is the spun bonding method. If bulkiness and softness are desired, the thermal bonding process is the preferred process.

[0032]

The top sheet 30 extends from the front edge to the rear edge of the product in the front-to-back direction and extends laterally more than the absorbent material 56 in the transverse direction WD. For example, when the starting point of the standing assembly 60, described later, is closer to the center in the transverse direction than the side edge of the absorbent material 56, appropriate deformation can be provided, for example, the width of the top sheet 30 can be made shorter than the maximum width of the absorbent material 56, if necessary.

[0033]

(intermediate sheet)

In order to quickly transfer liquid that has passed through the top sheet 30 into the absorbent material, an intermediate sheet (also referred to as a "second sheet") 40 having a liquid transport rate higher than the top sheet 30 can be placed. The intermediate sheet 40 is used to quickly transfer liquid into the absorbent material in order to improve the absorbent performance of the absorbent material and prevent the phenomenon of "return" of the absorbed liquid from the absorbent material. Intermediate sheet 40 may be omitted from the design.

[0034]

Examples of the intermediate sheet 40 include a material similar to that of the top sheet 30, a hydroentangled nonwoven, a spunbonded nonwoven, an SMS composite nonwoven (composed of spunbond/meltblown/spunbond layers), a cellulose nonwoven, a blended cellulose and rayon sheet. fibres, spot bonded nonwovens and crepe paper. In particular, an air-blown nonwoven fabric is preferred due to its high bulk. As the air-blown nonwoven fabric, a composite fiber having a core-sheath structure is preferably used. In this case, the polymer used for the core may be polypropylene (PP), but is preferably a polyester (PET) having high rigidity. The density is preferably 17-80 g/m ² and more preferably 25-60 g/m ² . The starting fiber of the nonwoven material preferably has a fineness of 2.0-10 dtex. Mixed fibers of all or some of the original fibers, eccentric fibers containing an off-center core, hollow fibers, eccentric and hollow fibers can also be preferably used to provide a high bulk of the nonwoven material.

[0035]

The intermediate sheet 40 in the example shown is centrally located so as to be less than the width of the absorbent material 56, but may be located across the entire maximum width. The intermediate sheet 40 may be located along the entire maximum length of the diaper, but may be located only in the intermediate area, covering the position of the body exudates, as in the example shown.

[0036]

(Liquid-impermeable polymer film)

The liquid-impervious resin film 11 is not particularly limited as long as moisture permeability is ensured. However, for example, it is possible to suitably use a microporous sheet obtained by mixing an inorganic filler into an olefin polymer such as polyethylene or polypropylene, forming the sheet, and then stretching the sheet in the direction of one or two axes. Obviously, the liquid-impermeable resin film 11 does not include a liquid-impervious resin film containing a nonwoven fabric as a base to improve hydrophobicity.

[0037]

Desirably, the liquid-impervious resin film 11 extends in the same area as the absorbent material 56, or a wider area in the front-back direction LD and the transverse direction WD. However, for example, if another water barrier is available, it is not necessary to cover the end portion of the absorbent material 56 in the front-back direction LD and the transverse direction WD if necessary. On the inner surface of the liquid-impervious polymeric film 11, an indicator can be placed that is colored or discolored by the action of the liquid component of body exudates. A well-known indicator can be used as an indicator, without particular limitation. For example, an indicator may be formed from a plate element containing a colorant that exhibits a color reaction when in contact with water in body exudates and/or a colorant that senses the pH level in water to show a color reaction, a paint or adhesive containing a reagent, which exhibits a bleaching reaction due to reaction with body fluids, i.e. a reaction which causes smearing or discoloration of the colorant due to the dissolution (dispersion) of the colorant in the urine or other visual change, or a reagent which exhibits a visual change upon contact with water or fluid in body secretions, (indicator reaction agent). As a coloring agent that exhibits a color reaction upon contact with water in body exudates, a coloring agent containing a water-soluble and water-degradable dye or leuco dye and a developer such as a phenolic compound, an acidic agent, or an electron affinity agent that exhibits dye color.

[0038]

(outer non-woven fabric)

The outer nonwoven fabric 12 covers the entire surface on the outside of the liquid-impervious resin film 11 and gives the outer surface of the product a linen-like appearance. The outer nonwoven material 12 is not particularly limited. Examples of raw fiber for this material include synthetic fiber such as polyolefin fiber, including polyethylene and polypropylene, polyester-based fiber or polyamide-based fiber, regenerated fiber such as viscose fiber or cupra, natural fiber, such as cotton. Examples of the manufacturing method include a hydroentangling method, a spinning bonding method, a thermal bonding method, an air stuffing method, and a needle punched method. However, long fiber nonwoven fabric such as spunbonded nonwoven fabric, SMS type nonwoven fabric or SMMS type nonwoven fabric is suitable in terms of obtaining both texture and strength. The nonwoven material can be used as a single sheet or as a multilayer sheet formed from a plurality of sheets. In the latter case, the nonwoven materials are preferably bonded to each other with a hot melt adhesive or the like. In this case, the outer nonwoven fabric 12 preferably has a fiber fineness of 1.0-6.0 dtex, a fiber density of 10-45 g/m ² , and a thickness of 0.1-3.0 mm. However, the outer nonwoven material 12 is not limited to these values within the above limits.

When the outer nonwoven material 12 contains the cellulosic nanofiber layer 15, the portion containing the cellulosic nanofiber layer 15 is necessarily rigid, and the outer surface of the absorbent article may have a rigid texture. Therefore, it is desirable to make it difficult to transfer the stiffness of the cellulosic nanofiber layer 15 in order to reduce deterioration in the texture of the outer surface of the absorbent article by coating the cellulosic nanofiber layer 15 with a relatively hard and dense outer nonwoven fabric 12. In this case, the outer nonwoven fabric preferably has a fiber fineness of 1.0- 6.0 dtex, fiber density 10-45 g/m ² and thickness 0.1-3.0 mm. However, the outer nonwoven fabric 12 containing the cellulosic nanofiber layer 15 is not limited to these limits as long as the stiffness transfer of the cellulosic nanofiber layer 15 is difficult to reduce degradation of the texture of the outer surface of the absorbent article.

[0039]

(Standing Assembly)

In order to trap bodily secretions that move laterally on the top sheet 30 and prevent so-called lateral leakage, standing gathers 60 are preferably provided on both sides of the inner surface in the transverse direction WD, rising from the wearer's skin side. Of course, standing assemblies 60 may be omitted.

[0040]

When the standing assembly 60 is used, its design is not specifically limited, and any known design can be used. The standing assembly 60 in the example shown includes an assembly sheet 62 substantially continuous in the transverse direction WD and an elongated assembly elastic member 63 secured to the assembly sheet 62 in an anterior-rearward stretched state LD. For the assembly sheet 62, a hydrophobic nonwoven material may be used, and for the assembly elastic member 63, rubber thread or the like may be used. As shown in FIG. 1 and 2, a plurality of resilient members may be disposed on each side, or one resilient member may be disposed on each side.

[0041]

The inner surface of the assembly sheet 62 has a joint start position in the transverse direction WD on the side portion of the top sheet 30. A portion from the joint start position outward in the transverse direction is connected to the inner surface of each side flap portion SF, that is, in the example shown, connected to the side portion a liquid-impervious resin film 11 and a side portion of the outer non-woven material 12 located on the outer portion in the transverse direction with a hot melt adhesive or the like.

[0042]

Around the circumference of the leg, the inner side of the connection start position of the standing assembly 60 in the transverse direction is fixed to the top sheet 30 at both end portions in the anterior-posterior direction of the article. However, the area between them is an unattached free area, and the free area rises under the action of the contraction force of the elastic member 63 and comes into close contact with the surface of the body.

[0043]

(End flap section and side flap section)

The band-type disposable diaper in the example shown has a pair of end flap portions EF not including the absorbent material 56 and extending into the front side and back side of the absorbent material 56, and a pair of side flap portions SF not including the absorbent material 56 and extending into side is larger than both side edges of the absorbent material 56.

[0044]

(flat assembly)

Attached to each side flap portion SF is a side elastic member 64 formed from an elongated elastic member such as a rubber thread in a state of extension in the front-rear direction LD, and the leg circumference of each side flap portion SF is formed as a flat assembly. The leg circumference elastic member 64 may be disposed between the assembly sheet 62 and the liquid-impervious resin film 11, outside the vicinity of the position of the beginning of the connection in the transverse direction, on the attached portion of the assembly sheet 62, as in the example shown, and may also be disposed between the liquid-impervious resin film 11 and the outer nonwoven fabric 12 in the side flap portion SF. A plurality of leg springs 64 may be located on each side, as in the example shown, or only one leg spring 64 may be positioned on each side.

[0045]

(Connecting tape)

On each section SF of the side flap of the section of the back side B is a connecting tape 13 for detachable connection with the outer surface of the section F of the ventral side. When the diaper 10 is put on, the connecting bands 13 are rotated along the outer surface of the ventral side portion F on both sides of the waist, and the connecting portions 13A of the connecting bands 13 are connected to the corresponding positions of the outer surface of the ventral side portion F.

[0046]

The structure of the connecting tape 13 is not specifically limited. However, in the example shown, the connecting tape 13 includes: a tape attachment portion 13C attached to the side flap portion SF; a base sheet material forming a tape body portion 13B protruding from the tape fastening portion 13C; and a ventral side connecting portion 13A located at an intermediate portion in the transverse direction of the tape main member portion 13B on the base sheet material, and the end side of the connecting portion 13A is a tongue portion.

[0047]

As the connection portion 13A, the hook material (hook member) of the mechanical fastener (textile Velcro) or the pressure-sensitive adhesive layer can be placed. The hook material contains a plurality of engaging protrusions on its connecting surface. Examples of the shapes of the engaging protrusions include (A) a checkmark shape, (B) a J-shape, (C) a mushroom shape, (D) a T-shape, and (E) a double J-shape (a shape in which the J- shaped protrusions are connected to each other end-to-end), but any form is allowed.

[0048]

As the material of the base sheet formed from the belt attachment portion 13C to the belt body portion 13B, a nonwoven fabric, a plastic film, a laminated nonwoven fabric, paper, or a material composed of the above materials can be used. However, a spunbonded nonwoven fabric, an air-blown nonwoven fabric, or a hydrowoven nonwoven fabric having a fineness of 1.0-3.5 dtex, a density of 20-100 g/m ² and a thickness of not more than 1 mm is preferable.

[0049]

(Orienting sheet)

The orienting sheet 20 for facilitating the connection is preferably positioned at the attachment point of the connecting tape 13 in the ventral portion F. In the case where the connecting portion 13A is formed from a hook material, the orienting sheet 20 can be a sheet in which multiple thread loops forming hook material engaging protrusions intertwined therewith are disposed on the inner surface of the base sheet material formed from plastic film or non-woven fabric. In the case of the adhesive material layer, a material obtained by stripping the surface of a base sheet material formed from a plastic film having a smooth surface with high adhesiveness can be used. When the attachment site of the connecting tape 13 at the ventral side portion F is formed of a nonwoven material, for example, when the outer nonwoven material 12 is positioned as in the embodiment shown, the orienting sheet 20 may be omitted, and the hook material may be engaged with the fibers of the outer nonwoven material 12 to be connection. In this case, the orienting sheet 20 may be positioned as a mark between the outer nonwoven fabric 12 and the liquid-impervious resin film 11.

[0050]

(Cellulose nanofiber)

Cellulosic nanofibers refers to fine cellulose fibers obtained by defibration of wood pulp, and generally, cellulose fibers containing fine cellulose fibers having an average fiber width in the range of nanoscale (not less than 1 nm to not more than 1000 nm). Cellulosic nanofibers having an average fiber width (median diameter) of no more than 100 nm are preferred, and cellulose nanofibers of 10-100 nm are particularly preferred. The cellulosic nanofiber layer within these limits has a high odor contact efficiency and more effectively reduces odor from the outside of the absorbent article. However, cellulose nanofibers are not limited to these limits.

Cellulose fibers have a structure in which a myriad of β-glucose molecules are linked primarily to each other in the form of a chain with β-1,4-glycosidic bonds. β-Glucose contains an -H group, an -OH group, and the like.

[0051]

The present application describes a method for measuring the average fiber width of cellulose nanofibers.

First, 100 ml of an aqueous dispersion of cellulose nanofibers having a solids concentration of 0.01 to 0.1% by mass is filtered through a Teflon (registered trademark) membrane filter, and solvent displacement is performed once with 100 ml volume of ethanol and three times 20 ml volume of t-butanol.

Then, the resulting product is dried under vacuum and coated with osmium to obtain a sample. This sample is observed in a scanning electron microscope (SEM) image at 5,000-, 10,000- or 30,000-fold magnification (in this example, at 30,000-fold magnification), depending on the width of the fibers forming the sample. In particular, two diagonals are drawn on the observed image, and three straight lines are randomly drawn passing through the intersection of the diagonals. In addition, a total of 100 fiber rods were visually measured crossing three straight lines. Then, the median diameter is obtained from the measured values as the average fiber width. It should be noted that the average fiber width is not limited by the median diameter of the measured values.

For example, as the average diameter of the fibers, you can take the number average diameter or typical diameter (the most common diameter).

[0052]

Examples of pulp that can be used to make cellulose nanofibers include cellulose, such as bleached hardwood kraft pulp (LBKP) or bleached softwood kraft pulp (NBKP), wood pulp, such as bleached thermomechanical wood pulp (BTMP), groundwood pulp (SGP), pressure groundwood pulp (PGW), refined groundwood pulp (RGP), chemical groundwood pulp (CGP), thermal groundwood pulp (TGP), abraded wood pulp (GP), thermomechanical pulpwood (TMP) , chemical-thermomechanical wood pulp (CTMP) or refined mechanical wood pulp (RMP), recycled pulp made from wrapping paper, kraft paper, magazine waste, newsprint, poster paper, office waste paper, cardboard waste, fine white paper waste paper, drawing paper waste, etching paper waste, certificate paper waste, or paper waste wood-pulp pulp, and decontaminated pulp (DIP), obtained by removing printing inks from pulp from recycled paper. The above fibrous masses can be used alone or in combination of at least two of their types, as long as the effects of the present invention are not lost. In addition, the pulp can be subjected to chemical treatment, such as carboxymethylation.

[0053]

Examples of the method for making cellulose nanofibers include mechanical methods such as high pressure homogenizer method, microfluidizer microfluidization method, attrition pulverizer method, ball mill freeze pulverization method, and ultrasonic pulverizing method, but are not limited to these methods. In addition, the formation of nanofibers is facilitated by the combined use of oxidative treatment using TEMPO (2,2,6,6-tetramethylpiperidin-1-yl)oxyl, phosphoric acid esterification treatment, acid treatment, and the like.

[0054]

Typically, as shown in FIG. 8-10, the cellulosic nanofiber layer 15 may be interposed between the liquid-impervious polymeric film 11 and the outer nonwoven fabric 12. Note that symbol H in FIG. 8-10 denotes an adhesive, such as a hot melt adhesive for bonding the liquid-impervious resin film 11 to the outer nonwoven fabric 12. However, as described above, the liquid-impervious resin film 11 can be attached to the outer nonwoven fabric 12 by welding or the like. When such a layer 15 of cellulosic nanofibers is interposed between the liquid-impervious polymeric film 11 and the outer nonwoven fabric 12, the odor of body exudates which has penetrated through the liquid-impervious polymeric film 11 is adsorbed by the layer 15 of cellulose nanofibers. When the odor permeates through the cellulose nanofiber layer 15 due to this adsorption, the odor concentration decreases. For example, in the case where a wearer of a disposable band-type diaper wears a garment on the outside of the diaper, the residual odor that has already been released to the outside from the diaper remains inside the garment and is again adsorbed by the cellulose nanofiber layer 15 of the diaper. This further reduces the concentration of odor escaping out of the diaper.

[0055]

In addition, since the cellulose nanofiber layer 15 does not block moisture, it is unlikely that the mustiness-preventing ability will be lost during wear. In addition, due to the high hygroscopicity of the cellulose nanofibers, moisture is retained in the cellulose nanofiber layer 15, and the outer surface of the product or undergarment does not feel wet at all.

[0056]

It should be noted that the cellulosic nanofiber layer 15 need not be positioned between the liquid-impervious polymeric film 11 and the outer nonwoven fabric 12 and need only be positioned in the wrap region of the absorbent material 56 from the outside when the diaper is shaped for disposal (essentially cylindrical). shape) as shown in Fig. 12. For example, in the case where the outer nonwoven material 12 is not placed, the cellulosic nanofiber layer 15 may be located on the outer surface of the liquid-impermeable polymeric film 11. Body exudates are in the absorbent material 56 or the liquid-permeable topsheet 30. When the cellulosic layer 15 nanofibers is located in the liquid-impervious polymeric film 11 or the outer nonwoven fabric 12 located on the side of the outer surface of the absorbent material 56 or the liquid-permeable top sheet 30, the liquid-impermeable polymeric film 11 or the outer nonwoven fabric 12 covers body exudates when forming a mold for waste (essentially cylindrical shape). Therefore, it is possible to reduce the spread of odor to the outside.

[0057]

A band-type disposable diaper that has already been used is discarded, for example, as follows. The diaper is removed from the wearer and folded and rolled from the ventral side edge to the dorsal side edge so that the inside surface of the diaper becomes the inside of the fold. After the twisting is completed, the connecting tape 13 extending outward in the transverse direction is attached to the outer nonwoven fabric 12 (outer surface side of the diaper) so that the twist is not loosened. As a result, the diaper has a substantially cylindrical shape, as shown in FIG. 12(a). When the diaper is tightly rolled without a gap (the number of turns is large), the substantially cylindrical shape is relatively thin, and the substantially cylindrical side surface 91 has a relatively small area. Moreover, when the diaper is rolled through the gap (the number of turns is small), the substantially cylindrical shape is relatively thick, and the substantially cylindrical side surface 91 has a relatively large area. In addition, as an example of discarding the diaper, the diaper can be disposed of as follows. The diaper is rolled from the end of the ventral side to the end of the dorsal side to be folded into a state in which the diaper is deployed. When the diaper is rolled up to the end of the dorsal side, the connecting tape 13 extending outward in the transverse direction is fixed to the outer nonwoven fabric 12 (outer surface side of the diaper) so that the twist is not loosened. However, the method for disposing of the diaper in the waste varies depending on the caregiver and is not limited to the above method. It should be noted that in the case where the disposal tape 71 protrudes from both side portions of the back side portion of the diaper or protrudes from the intermediate portion in the transverse direction of the back side portion, a form in which the disposal tape is attached to the outer surface of the diaper in a state, wherein the diaper is folded or folded such that the inner surface of the diaper is the inner side at the time of disposal.

[0058]

The number of turns depends on the trustee. Therefore, the area in which the cellulose nanofiber layer 15 is placed is not particularly limited, but is preferably the area within which the liquid-impervious resin film 11 is overlapped by the outer nonwoven fabric 12. In the case where the disposal tape 71 and the connecting tape 13 are dorsal side of the outer surface of the diaper, the length Y of the layer 15 of cellulose nanofibers in the anterior-posterior direction LD is preferably equal to the length from the edge of the diaper from the dorsal side to the center of the diaper. The length Y is preferably 1/2, more preferably 1/3 and even more preferably 1/4 of the maximum length L of the diaper. When the layer 15 of cellulosic nanofibers is located in said region, the side surface 91 (ie, corresponding to the side surface 91 of the cylinder) when the diaper is given a substantially cylindrical shape, is surrounded by the layer 15 of cellulosic nanofibers. In the case where the disposal tape 71 and the connecting tape 13 are on the ventral side of the outer surface of the diaper, the length Y of the cellulosic nanofiber layer 15 in the anterior-posterior direction LD may be equal to the length from the ventral side edge of the diaper to the center of the diaper.

[0059]

In addition, the cellulosic nanofiber layer 15 may be located in the region of all or part of the outer surface of the connecting tape 13. When using this configuration, the bottom surfaces 92 and 92 in a substantially cylindrical shape are also completely covered by the cellulosic nanofiber layer 15. Therefore, the odor is effectively reduced. The cellulosic nanofiber layer 15 may be located in the area of all or part of the side flap section SF. However, the cellulosic nanofiber layer 15 should not be located on the bonding tape 13 or the side flap portion SF, depending on the application of the absorbent article, without being limited to the above.

[0060]

It should be noted that the underpants-type disposable diaper is discarded as follows, for example. The diaper is removed from the user. The pant-type disposable diaper is pre-folded so that the dorsal side and the ventral side are aligned with each other. The diaper is rolled up from the center of the outer surface towards the dorsal side edge to be rolled up. After the folding is completed, the disposal tape 71 located on the dorsal side of the outer surface is pulled out in the direction of the dorsal side edge and fixed to the outer surface of the outer nonwoven fabric 12 (the outer surface of the diaper) so that the twist is not loosened. As a result, the diaper has a substantially cylindrical shape, as shown in FIG. 12(b).

[0061]

The inventor of the present invention has found that the cellulose nanofiber layer 15 itself has sufficient adhesiveness and produces an odor physical adsorption effect to reduce odor. In the case where the cellulosic nanofiber layer 15 is sandwiched between the liquid-impervious resin film 11 and the outer nonwoven fabric 12, the cellulosic nanofiber layer 15 can come into contact with the odor in the atmosphere outside the disposable diaper. Therefore, the cellulose nanofiber layer 15 has a high odor contact efficiency, and the odor outside the disposable diaper, in particular the odor inside the storage container, when the disposable diaper is temporarily stored in the storage container, can be reduced more efficiently.

For example, a disposable diaper or the like is used in such a form that the disposable diaper or the like is folded or folded so that the body exudate sticking surface is the inside after use, when shaped for disposal, is placed in a highly sealed storage container, for example , sanitary box or diaper storage container, for temporary storage and placed in a trash bag and discarded when the number of diapers stored in the container reaches a certain level. After use, the disposable diaper emits a strong smell of bodily secretions, which creates discomfort for the user.

The outer surface of the disposable diaper is covered by the dorsal side portion, and the odor, the odor generated by the body exudates adhering to the inner surface of the diaper or the body exudates absorbed by the absorbent material 56, is emitted to the outside through the dorsal side portion of the outer surface. When the cellulosic nanofiber layer 15 is disposed in the back side portion, the cellulosic nanofiber layer 15 is located in the main odor path in the waste mold in which the diaper is rolled or folded, and therefore the odor reducing effect is more pronounced. In addition, in the form for disposal in the waste, in which the diaper is rolled up or folded, the layer 15 of cellulose nanofibers is placed closer to the outer surface. Therefore, the odor reduction effect is also exhibited in relation to the odor present outside the product, such as the odor in the storage container.

[0062]

One of the main components of the smell of body secretions is methyl mercaptan (CH ₃ SH). The cellulose nanofiber layer 15 adsorbs methyl mercaptan and thereby reduces the odor concentration of body exudates. Adsorption is mainly due to physical adsorption. In particular, methyl mercaptan is adsorbed by the layer 15 of cellulose nanofibers through the van der Waals force. Cellulosic nanofibers typically have fiber widths of at least 4 nm and at most 1000 nm, fiber lengths of at least 5 µm, high elongation (at least 5 for low elongation cellulose nanofibers, at least 1250 for high elongation cellulose nanofibers), and large specific surface area, and have a very high physical adsorption capacity.

[0063]

As shown in FIG. 8(b), a layer 15 of cellulosic nanofibers may be formed on the inner surface of the outer nonwoven fabric 12. As shown in FIG. 9, the cellulose nanofiber film 15F may be interposed between the liquid-impervious resin film 11 and the outer nonwoven fabric 12. As shown in FIG. 10, a sheet 16 of nonwoven fabric, paper, or the like, having a cellulose nanofiber layer 15 formed thereon, may be interposed between the liquid-impervious resin film 11 and the outer nonwoven fabric 12. However, as shown in FIG. 8(a), the cellulose nanofiber layer 15 is preferably formed on the outer surface of the liquid-impermeable resin film 11. In addition, when the cellulose nanofiber layer 15 is applied to the liquid-impermeable resin film 11 formed from the moisture-permeable resin film, the cellulose nanofibers are formed into a film. . Therefore, the odor-reducing ability of the liquid-impervious resin film 11 and its strength are improved, and the elongation is effectively reduced. In particular, the liquid-impermeable resin film 11 formed from the moisture-permeable resin film can be continuously applied with decorative printing including many constituents such as letters (size, brand name, manufacturer's name, pattern name, etc.) , regularly repeated in the front-back direction LD and the cross direction WD, drawings or the like, or intermittent decorative printing for printing on only one or both the front and back sides of the product, as in the product logo, a pattern of letters or photos. However, when such decorative printing is performed, it is desirable that the elongation of the liquid-impervious resin film 11 be small.

[0064]

When the cellulose nanofiber layer 15 is applied to the liquid-impermeable resin film 11 formed from the liquid-permeable resin film, the liquid-impermeable resin film 11's odor reduction ability and strength are increased, but the liquid-impermeable resin film 11 is rigid. Therefore, it is desirable that the density of the base material of the liquid-impervious resin film 11, that is, the density of the liquid-impervious resin film, be reduced to, for example, about 10-12 g/m ² to compensate for the decrease in softness. Generally, lowering the density of the liquid-permeable polymer film to this level may increase the likelihood of pinhole formation and may reduce hydrophobicity. However, the cellulose nanofiber layer 15 applied to the liquid-permeable resin film can prevent such a decrease in hydrophobicity and can exhibit an odor reducing effect.

[0065]

To enhance the ability to reduce odor, it is advisable to use more cellulose nanofibers. However, when their number is too high, the product becomes excessively rigid. Therefore, the preferred density of the applied layer 15 of cellulose nanofibers is approximately 0.1-5.0 g/m ² . A more preferred density of the applied layer 15 of cellulose nanofibers is approximately 0.5-3.0 g/m ² .

The layer 15 of cellulose nanofibers may be located on all or part of the surface of the area in which the layer 15 of cellulose nanofibers is placed. In the case where the cellulosic nanofiber layer 15 is disposed in a portion of the area in which the cellulosic nanofiber layer 15 is placed, the cellulosic nanofiber layers 15 are preferably arranged in a large number of positions at intervals. For example, layers 15 of cellulose nanofibers may be arranged in vertical stripes (see FIG. 11). In addition, the cellulose nanofiber layers 15 may be arranged in the form of horizontal stripes, diagonal stripes, or lattices. Thus, even when the layers of cellulose nanofibers 15 are arranged in a large number of positions at intervals, the layers of cellulose nanofibers 15 themselves have an adhesive ability. Therefore, a portion of the outer nonwoven 12 is unlikely to curl and is unlikely to peel off the liquid-impervious polymeric film 11.

In addition, the cellulose nanofiber layers 15 can be interposed between the liquid-impervious resin film 11 and the outer nonwoven fabric 12 at multiple positions at intervals, and can be attached directly to at least the liquid-impermeable resin film 11, the liquid-impermeable resin film 11 can be attached to the outer nonwoven fabric 12 at a site not containing the cellulose nanofiber layers 15 with a hot melt adhesive or the like, and part of each or all of each of the cellulose nanofiber layers 15 should not be coated with a hot melt adhesive or the like. In view of the adhesiveness of the cellulose nanofiber layer 15, the efficiency of its contact with external odor, and the texture of the outer surface, it is desirable to attach the cellulose nanofiber layer 15 to the outer surface of the liquid-impervious polymer film 11 and cover its outer surface with an outer nonwoven fabric 12. In this case, the outer nonwoven the material 12 is usually bonded to the liquid-impervious polymer film 11 with a hot melt adhesive or the like. However, coating the cellulose nanofiber layer 15 with a hot-melt adhesive or the like is not desirable from the viewpoint of improving the contact efficiency between the cellulose nanofiber layer 15 and the odor. On the contrary, as described above, when a structure is formed in which the cellulose nanofiber layers 15 are arranged at a plurality of positions at intervals, the liquid-impermeable resin film 11 is bonded to the outer nonwoven fabric 12 at a given interval portion, and part of each or all of each of the layers 15 cellulose nanofibers is not coated with a hot-melt adhesive or the like, the decrease in contact efficiency between each of the cellulose nanofiber layers 15 and the odor can be reduced if the outer nonwoven fabric 12 is bonded to the liquid-impervious resin film 11, which is desirable.

In addition, the cellulose nanofiber layer 15 is rigid. Therefore, when the cellulosic nanofiber layer 15 is arranged continuously in a wide area, the softness of the article may deteriorate. On the contrary, when the layers of cellulose nanofibers 15 are arranged at intervals, the reduction in softness can be reduced if the layers of cellulose nanofibers 15 are arranged in a wide area. In addition, cellulose nanofibers absorb odor through physical adsorption. Cellulosic nanofibers are fine fibers and therefore have a high relative elongation and a relatively large specific surface area. Therefore, the cellulosic nanofibers have a higher physical adsorption capacity than conventional deodorant particles and provide a strong odor reducing effect even if the layers of cellulosic nanofibers 15 are spaced. In addition, the amount of cellulose nanofibers used can be reduced and hence the cost effectiveness is also very significant.

In addition, the cellulosic nanofiber layer 15 can only be located in the region where the cellulosic nanofiber layer 15 is overlapped by the absorbent material 56. The area containing the cellulosic nanofiber layer 15 is necessarily rigid. Therefore, the rigidity of the cellulose nanofiber layer 15 is hidden by the softening action of the absorbent material 56 in the region where the cellulose nanofiber layer 15 is overlapped by the absorbent material 56 on the skin side of the wearer.

[0066]

The cellulosic nanofiber layer 15 can be made in a known manner, for example, by converting the cellulosic nanofibers into the form of a dispersion of cellulosic nanofibers, applying the dispersion of cellulosic nanofibers to a desired sheet such as a liquid-impervious polymer film 11, and drying the dispersion of cellulosic nanofibers to fix and form the cellulosic nanofibers. on the required sheet. It should be noted that when the liquid form of cellulose nanofibers is applied to a fibrous sheet, such as paper or non-woven material, using the manufacturing method of applying liquid form of cellulose nanofibers in the above way, part of the liquid form of cellulose nanofibers penetrates into the sheet, but the cellulose nanofibers are concentrated on the surface. . Therefore, the cellulosic nanofiber layer 15 can be fixed and formed on the sheet. The solution in which the cellulose nanofibers are dispersed is not particularly limited, but examples thereof include water, a lower alcohol such as ethanol, and a volatile organic solvent such as acetone.

[0067]

A dispersion of cellulose nanofibers is obtained by dispersing cellulose nanofibers in water. The concentration (w/v) of the cellulose nanofiber dispersion is preferably 0.1-10%, more preferably 1.0-5.0% and particularly preferably 1.5-3.0%.

[0068]

The viscosity on a type B viscometer (60 rpm, 20° C.) of the cellulose nanofiber dispersion is, for example, not more than 300 cP, preferably not more than 200 cP, and more preferably not more than 50 cP. By reducing the viscosity of the cellulose nanofiber dispersion on the type B viscometer to a low level in this manner, the cellulose nanofibers can be uniformly applied to the surface of the sheet, and the surface properties of the sheet are evenly improved.

[0069]

The cellulose nanofibers can be applied not only by spraying the cellulose nanofibers onto the desired surface, but also by using a transfer method by a letterpress method or the like.

[0070]

Cellulosic nanofibers are usually produced by decomposition of plant materials or biosynthesis using bacteria. Cellulosic nanofiber structures are obtained by polymerization of glucose and are considered harmless.

[0071]

<Test to confirm the effect>

The layer 15 of cellulose nanofibers was tested to confirm the effect in two types of tests. The characteristics of the absorbent material 56, the liquid-impervious resin film 11, the outer nonwoven material 12, and the cellulose nanofibers used in these tests to confirm the effect are as follows.

[0072]

It should be noted that the absorbent material 56 is obtained by homogeneous mixing of pulp and superabsorbent polymer particles and contains 180 g/m ^{2 of} pulp and 220 g/m ^{2 of} superabsorbent polymer particles.

[0073]

As the superabsorbent resin particles, particles were used which had a water absorption capacity of 33 g/g, a water absorption rate of 35 seconds, and a gel strength of 3800 Pa, and in which the proportion of particles remaining on a 500 µm standard sieve (JIS Z8801-1: 2006) was 18% by weight, and the proportion of particles remaining on a 180 µm standard sieve (JIS Z8801-1: 2006) was 80% by weight when sieving was performed using a 500 µm standard sieve (shaking for five minutes) , and particles falling through a sieve using this separation were separated using a 180 μm standard sieve (shaking for five minutes).

[0074]

As the liquid-impermeable resin film 11, a liquid-pervious polyethylene film having a density of 18 g/m ² was used. The moisture permeability of the liquid-impervious resin film 11 (JIS Z 0208 method, temperature and humidity conditions B (under the conditions of temperature 40°C and humidity 90%)) was 9000 g/m ² in 24 hours in test 1 to confirm the effect, and was 9000 g/m ² for 24 hours and 10,000 g/m ² for 24 hours in test 2 to confirm the effect.

[0075]

As the outer nonwoven fabric 12, an air-blown nonwoven fabric with a density of 20 g/m ² , made of a composite fiber (fineness: 2.0 dtex) having a core-sheath structure with polyethylenes (in the sheath) and polyethylene terephthalate (in the core) was used as the outer non-woven fabric 12. ).

[0076]

The cellulose nanofibers used in this test were cellulose nanofibers made from 100% bleached softwood kraft pulp (NBKP). In addition, cellulose nanofibers having an average fiber width (median diameter) of 49 nm were used. These cellulosic nanofibers were obtained by processing NBKP in a refiner to separate into coarse fibers and then processing coarsely separated cellulosic nanofibers four times using a high pressure homogenizer to separate into fibers. The reported average fiber width was measured as described above to measure the average fiber width of cellulose nanofibers.

[0077]

<Test 1 to confirm the effect>

Prepared the following diaper sample, and measured the concentration of methyl mercaptan, which is the main component of the smell of body secretions. The purpose of this test is to confirm how much the concentration of methyl mercaptan is reduced in a diaper containing a layer of 15 cellulose nanofibers.

[0078]

(Sample diaper)

The following diaper samples were used in this test.

Sample 1 is a diaper in which the cellulose nanofiber layer 15 is interposed between the liquid-impervious resin film 11 and the outer nonwoven fabric 12, and deodorant (sugar cane extract MSX-245 (manufactured by Mitsui Sugar Co., Ltd.)) is not applied.

Sample 2 is a diaper in which a layer 15 of cellulose nanofibers is placed on the inner surface of the liquid-permeable top sheet 30 and a deodorant (MSX-245) is applied to the outer surface of the outer nonwoven fabric 12 (the outer surface of the diaper).

Sample 3 is a diaper that lacks the cellulose nanofiber layer 15 and has a deodorant (MSX-245) applied to the outer surface of the diaper.

Sample 4 is a diaper with no cellulose nanofiber layer 15 and no deodorant (MSX-245).

[0079]

In Sample 1, 50 g of a dispersion of cellulose nanofibers having a concentration of 0.1% was uniformly applied to the entire outer surface of the liquid-impermeable polymer film 11 and dried to prepare a liquid-impermeable polymer film 11 having a layer 15 of cellulose nanofibers with a density of 3.0 g/ m ² . As cellulose nanofibers, cellulose nanofibers obtained from 100% NBKP and having an average fiber width (median diameter) of 49 nm were used.

[0080]

In Sample 2, 50 g of the cellulose nanofiber dispersion having a concentration of 0.1% was evenly applied to the entire inner surface of the liquid-permeable topsheet 30 and dried to prepare a liquid-permeable topsheet 30 containing 2.5 g of deodorant (MSX-245) and a layer 15 of cellulose nanofibers with a density of 3.0 g/m ² .

[0081]

In sample 3, 2.5 g of deodorant (MSX-245) was dissolved in water to make a 50 g solution. The solution was evenly applied to the entire outer surface of the liquid-impermeable resin film 11 and dried to prepare a liquid-impermeable resin film 11 containing a deodorant (MSX-245).

[0082]

(Performing a test)

50 ml of methyl mercaptan at a concentration of 0.3% was added to the center of the absorbent 56 on the inner surface of the diaper. This diaper was placed in a gas-tight bag, sealed and allowed to stand. One hour after the introduction of the odorous liquid, the concentration of methyl mercaptan in the bag was measured by the indicator tube method. The indicator tube method is a method of sucking 500 ml of a gas to be tested with an indicator tube and measuring the concentration (ppm) in the target gas. The indicator tubes used were Nos. 71 and 71H methyl mercaptan indicator tubes manufactured by Gastec Corporation.

[0083]

(Results)

The methyl mercaptan concentration of the most odorous liquid was 500 ppm. for 500 ml of gas. Table 1 presents the results of measurement with indicator tubes.

[0084]

[Table 1]

[0085]

In Table 1, the odor reduction ratio of methyl mercaptan in sample n (n=1, 2, or 3) is determined by the following numerical formula.

[0086]

[Numeric Formula 1]

[0087]

In the numerical formula, the concentration in sample 4 after one hour refers to the concentration of methyl mercaptan in the bag, measured one hour after sample 4 was placed in the bag, sealed and allowed to stand. The concentration in sample n after one hour refers to the concentration of methyl mercaptan in the bag, measured one hour after sample n was placed in the bag, sealed and allowed to stand.

[0088]

It turned out that each of the samples 1-3 contains a concentration lower than sample 4 and provides the effect of reducing the smell. When sample 1 is compared with sample 2, sample 1 is found to have a higher odor reduction ratio. This is explained as follows. Namely, this is due to the fact that the odorous liquid dripped onto the diaper is absorbed by the absorbent material 56, and sample 2 is a diaper in which the layer 15 of cellulose nanofibers is located on the inner surface of the absorbent material 56 and cannot delay the spread of methyl mercaptan towards the outer surface of the absorbent material. material 56.

[0089]

When sample 1 is compared with sample 3, sample 1 is found to have a higher odor reduction ratio. This shows that the cellulose nanofiber layer 15 has a higher odor reduction ratio than the deodorant (MSX-245) under the conditions of this test. Therefore, sample 1 was confirmed to have a higher odor reduction ratio than samples 2 and 3.

[0090]

<Test 2 to confirm the effect>

Prepared the following diaper sample, and measured the concentration of methyl mercaptan, which is the main component of the smell of body secretions. The purpose of this test is to confirm how much the concentration of methyl mercaptan is reduced in a diaper containing a layer of 15 cellulose nanofibers.

[0091]

(Sample diaper)

The following diaper samples were used in this test.

Nine samples S1-S9 were used. As shown in Table 2, each of Samples S1-S6 has a moisture permeability of 9,000 g/m ² ⋅ in 24 hours, and each of Samples S7-S9 has a moisture permeability of 10,000 g/m ² ⋅ in 24 hours. The density of the layer of 15 cellulose nanofibers was controlled in the range of 0.1-1.5 g/m ² . Cellulosic nanofiber layers 15 were arranged on a liquid-impervious polymer film 11 in the form of strips with a deposition width of 5 mm and a deposition interval of 5 mm, and hot melt adhesive 81 was applied only to the area where the cellulose nanofiber layer 15 was not laid. Cellulosic nanofibers made from 100% NBKP having an average fiber width (median diameter) of 49 nm were used as cellulose nanofibers.

[0092]

(Performing a test)

To prepare an odorous liquid, methyl mercaptan was dissolved in water so that its concentration (w/v) was 0.5%. 50 ml of this odorous liquid was added to the center of the absorbent 56 on the inner surface of the diaper. This diaper was placed in a gas-tight bag, sealed and allowed to stand. At zero hours, four hours and 24 hours after the addition of the odorous liquid, the concentration (ppm) of methyl mercaptan in the bag was measured by the indicator tube method. (JIS K 0804: 2014 gas detection tube measuring device).

[0093]

(Results)

The results are shown in Table 2. In Table 2, the density refers to the density (g/m ² ) when the cellulose nanofibers are deposited on the liquid-impermeable polymer film 11.

[0094]

[Table 2]

[0095]

Table 2 presents the concentration (ppm) of methyl mercaptan measured immediately after application of the odorous liquid (0 hours after application), four hours after application, or 24 hours after application, and the methyl mercaptan odor reduction ratio (%) for samples S1-S9 . In Table 2, the odor reduction ratio (%) is determined by the following numerical formula.

[0096]

[Numeric Formula 2]

[0097]

Here, in the numerical formula, the concentration in the sample S1 immediately after application refers to the concentration of methyl mercaptan measured immediately after the odorous liquid was introduced into the center of the absorbent material 56 for the sample S1.

The concentration in the Sm sample t hours after application refers to the concentration of methyl mercaptan measured after t hours for the Sm sample. The index m refers to any of 1-9, and t means any time from 0, 4, and 24.

[0098]

As can be seen from Table 2, when considering the odor reduction factor four hours after application, samples (S2-S9) in which cellulose nanofibers are applied tend to have a relatively higher odor reduction factor than sample (S1) in which cellulose nanofibers are applied. nanofibers are not deposited. In particular, each of samples 4-6 shows a particularly high odor reduction ratio.

[0099]

As follows from the above results, the application density of the cellulose nanofibers is preferably not less than 0.1 g/m ² , and more preferably not less than 0.5 g/m ² .

[0100]

<Explanation of terms in the description>

The following terms in the description have the following meanings, unless otherwise indicated in the description.

[0101]

"Anterior-posterior (longitudinal) direction LD" means a direction connecting the ventral side (anterior side) and dorsal side (posterior side), and refers to "dorso-abdominal direction" in the claims. "Lateral direction WD" means a direction orthogonal to the anterior-posterior direction (left to right direction).

[0102]

"Unfolded state" means a flat unfolded state, without contraction or slack.

[0103]

"Stretch ratio" means the value obtained when the natural length is 100%.

[0104]

"Gel strength" is measured as follows. In 49.0 g artificial urine (urine: 2% by weight, sodium chloride: 0.8% by weight, calcium chloride dihydrate: 0.03% by weight, magnesium sulfate heptahydrate: 0.08% by weight, deionized water: 97.09% by weight) add 1.0 g of superabsorbent polymer, and the resulting mixture is stirred with a stirrer. The gel thus formed is left in a thermostat at 40° C. and 60% relative humidity for three hours. Thereafter, the temperature was lowered to room temperature, and the gel strength was measured with a milk clot density meter (Curdmeter-MAX ME-500 manufactured by I. Techno Engineering Co., Ltd.).

[0105]

"Density" is measured as follows. The sample or test piece is pre-dried and then left in the test chamber or apparatus in the standard state (temperature of 23 ± 1°C and relative humidity of 50 ± 2% at the test site) to obtain a constant weight. Pre-drying refers to bringing the sample or test piece to constant weight in an environment of 100°C. It should be noted that pre-drying of fibers having a formal equilibrium moisture content of 0.0% is not required. A sample with dimensions of 100 mm x 100 mm is cut from a test piece having a constant weight using a sample preparation template (100 mm x 100 mm). Measure the weight of the sample. The weight is multiplied by 10 to calculate the weight per square meter to be used as the density.

[0106]

"Thickness" is measured automatically under conditions where the load is 0.098 N/cm ² and the pressure area is 2 cm ² using an automatic thickness gauge (KES-G5 manual compression gauge).

[0107]

"Water absorbency" is measured by JIS K7223-1996 "Test Method for Determining Water Absorbency of Superabsorbent Polymer".

[0108]

"Water absorption rate" means "time to end point" when the method of JIS K7224-1996 "Test Method for Determining Water Absorption Rate of Superabsorbent Resin" is carried out using 2g of superabsorbent polymer and 50g of saline.

[0109]

In the case where the external conditions for testing and measurement are not described, the test and measurement is carried out in a testing laboratory or device in the standard state (at the test site, withstand a temperature of 23±1°C and a relative humidity of 50±2%).

[0110]

The size of each section means the size in a state not in natural length, but in an unfolded state, unless otherwise indicated.

Industrial Applicability

[0111]

The present invention is applicable to conventional disposable diapers, such as a pant-type disposable diaper and a panty-type disposable diaper, in addition to a band-type disposable diaper as in the above example. Of course, the present invention also applies to another absorbent article, such as a sanitary napkin.

List of reference positions

[0112]

11 Liquid-tight plastic film

12 Outer nonwoven fabric

12A Connected section

13 Connecting tape

13A Connecting section

13B Section of the main element of the tape

13C Tape attachment area

15 Layer of cellulose nanofibers

20 Orientation sheet

30 Top sheet

40 Intermediate sheet

56 Absorbent material

58 Wrap sheet

60 Stand assembly

62 Assembly sheet

71 Recycling tape

86, 88, 89 Elongated elastic element

91 Side surface

92 Bottom surface

B Dorsal area

F Abdominal area

WD Cross direction

LD Front-back direction.

Claims (20)

1. Absorbent article containing: absorbent material; and a liquid-impervious polymeric film covering the outside of the absorbent material, an outer nonwoven material covering the outer surface of the liquid-impervious polymer film, wherein layers of cellulose nanofibers are located between the liquid-impervious polymer film and the outer non-woven material in a plurality of positions at intervals in at least one of the front-rear direction and the transverse direction and are attached directly to at least the liquid-impervious polymer film, the liquid-impermeable polymeric film is bonded to the outer nonwoven fabric at a site free of cellulose nanofiber layers with a hot melt adhesive, and some or all of each of the layers of cellulose nanofibers is not coated with a hot melt adhesive, and the layer of cellulose nanofibers is configured to come into contact with the odor in the atmosphere outside the absorbent article. 2. An absorbent article according to claim 1, comprising an outer nonwoven material covering the outer surface of the liquid-impervious polymeric film, wherein a layer of cellulose nanofibers is sandwiched between the liquid-impervious polymer film and the outer nonwoven fabric, and the outer nonwoven material has a fiber fineness of 1.0-6.0 dtex, a fiber density of 15-45 g/m ² and a thickness of 0.5-3.0 mm. 3. Absorbent article according to claim 1 or 2, containing: a ventral side portion located anteriorly from the center in the anterior-posterior direction, and a dorsal side portion located posteriorly from the center in the anterior-posterior direction; and a disposal tape protruding from both side portions of the dorsal side portion or protruding from an intermediate portion in the transverse direction of the dorsal side portion, wherein the cellulosic nanofiber layer is located in the dorsal side portion, and the cellulosic nanofiber layer is not located in the ventral side portion. 4. An absorbent article according to claim 1 or 2, wherein the cellulosic nanofiber layer is located only in the region where the cellulosic nanofiber layer is overlaid by the absorbent material. 5. An absorbent article according to claim 1 or 2, wherein the cellulose nanofibers of the cellulose nanofiber layer have an average fiber width of 10-100 nm, and the layer of cellulose nanofibers contains 0.1-5.0 g/m ^{2 of} cellulose nanofibers.

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