WO2014073376A1 - 吸収性物品 - Google Patents
吸収性物品 Download PDFInfo
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- WO2014073376A1 WO2014073376A1 PCT/JP2013/078668 JP2013078668W WO2014073376A1 WO 2014073376 A1 WO2014073376 A1 WO 2014073376A1 JP 2013078668 W JP2013078668 W JP 2013078668W WO 2014073376 A1 WO2014073376 A1 WO 2014073376A1
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- Prior art keywords
- sheet
- absorbent
- liquid
- basis weight
- fiber
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F13/00—Bandages or dressings; Absorbent pads
- A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
- A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers
- A61F13/511—Topsheet, i.e. the permeable cover or layer facing the skin
- A61F13/51104—Topsheet, i.e. the permeable cover or layer facing the skin the top sheet having a three-dimensional cross-section, e.g. corrugations, embossments, recesses or projections
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F13/00—Bandages or dressings; Absorbent pads
- A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
- A61F13/53—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium
- A61F13/534—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium having an inhomogeneous composition through the thickness of the pad
- A61F13/537—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer
- A61F13/53743—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer characterised by the position of the layer relative to the other layers
Definitions
- the present invention relates to absorbent articles such as disposable diapers and sanitary napkins.
- This type of absorbent article includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent disposed between these sheets, and is hydrophilic between the top sheet and the absorbent.
- an intermediate layer including fibers is arranged.
- covers this absorptive core is known.
- the core wrap sheet serves as a sheet for receiving the absorbent material during the production of the absorbent body, and plays a role of wrapping the absorbent core and shaping it after the production.
- water-permeable sheets such as thin paper, absorbent paper, and nonwoven fabric are used as the core wrap sheet.
- Patent Document 1 discloses an absorbent article in which a liquid trapping system is arranged, which includes a chemically cross-linked cellulose fiber between a topsheet and an absorbent core substantially free of cellulose.
- a liquid trapping system is arranged, which includes a chemically cross-linked cellulose fiber between a topsheet and an absorbent core substantially free of cellulose.
- the absorbent article described in Patent Document 1 has improved liquid handling characteristics as compared to conventional products, and is said to provide better drying properties.
- Patent Document 2 in an absorbent article comprising an absorbent body comprising a water-absorbing polymer and cellulose fibers, the cellulose fibers are crosslinked by cross-linking cellulose molecules or molecules with a crosslinking agent.
- the absorber is provided with a diffusion absorbent paper made with a basis weight of 20 to 60 g / m 2 , and the permeation time of the 85% by weight aqueous solution of glycerin is 100 seconds or less. It is also described.
- the absorbent article described in Patent Document 2 is said to have an excellent absorption rate, particularly a reabsorption rate, a high ability to immobilize body fluids, and excellent liquid return and liquid leakage prevention properties.
- Patent Document 3 discloses an absorbent core including a storage layer and a durable hydrophilic fluid-permeable core wrap, which is durable during storage, and is not easily washed away when wet.
- a non-woven hydrophilic coated core wrap that allows for rapid liquid penetration when exposed, wherein the coated hydrophilic enhancing composition has a particle size in an amount that improves hydrophilicity by about It is described to include nanoparticles that are from 1 to about 750 nanometers.
- Patent Document 3 also states that this “improves hydrophilicity” means that the liquid first when the composition is coated on a core wrap substrate to make a durable hydrophilic fluid-permeable core wrap. It is said that the run-through time for flowing out is 5 ml of liquid for a sample of 12.5 ⁇ 12.5 cm, and the fifth run-through time is about 6 seconds or less.
- the crosslinked cellulose fiber is more hydrophobic than a normal pulp fiber. Therefore, effects such as an increase in the liquid permeation speed from the top sheet side to the back sheet side and a difficulty in producing a liquid residue are exhibited.
- the core wrap sheet has a hydrophilizing agent on the surface of the constituent fibers of the originally water-repellent nonwoven fabric.
- the absorbent article When the absorbent article is attached with hydrophilicity, the discharge and absorption of body fluids such as urine are repeated during use of the absorbent article, so that the hydrophilizing agent contained in the core wrap sheet is externally contained together with the body fluid. As a result, there is a problem that the hydrophilicity of the core wrap sheet is lowered (water repellency is improved) and the liquid permeability is lowered.
- the permeation / absorption rate of the body fluid decreases, and the body fluid discharged on the top sheet is an intermediate layer disposed on the non-skin facing side of the top sheet, or the intermediate layer It is easy to stay between the absorbent body and the absorber, and the liquid residue is likely to be generated, and there is a possibility that the liquid returns to the surface sheet side increases.
- the nano-particle coating which is a hydrophilicity improving composition described in Patent Document 3
- the maintenance of the penetration time and durability hydrophilicity of a plurality of tests of a small amount of liquid are improved.
- this is a method of flowing 5 ml of liquid to a sample of 12.5 ⁇ 12.5 cm, and this amount of liquid is much less than the level of urination in a diaper, and the amount of liquid is so small that nanoparticles are used. It is hard for omission to occur.
- Patent Document 3 has a risk that the hydrophilicity does not last long because nanoparticles easily fall off for a plurality of tests of a large amount of liquid at the level of urination assuming actual use in a diaper. In addition, there is a possibility that the nanoparticles may fall off due to stress when processing the diaper. On the other hand, although it is necessary to devise the coating in order to suppress the dropping of the nanoparticles, Patent Document 3 does not disclose such a contrivance. However, in general, when such a device is incorporated in the manufacturing process, there arises a problem that the manufacturing cost increases.
- the present invention comprises a liquid-permeable surface sheet on the skin-facing surface side, a liquid-permeable back sheet on the non-skin-facing surface side, and an absorber disposed between both sheets, the surface sheet and the absorber
- An intermediate layer is disposed between the intermediate layer, the intermediate layer is configured to include a crosslinked cellulose fiber
- the absorbent body includes an absorbent core containing an absorbent material
- a core wrap sheet that covers at least the skin-facing surface of the absorbent core and includes paper or a hydrophilic nonwoven fabric
- the liquid wrap time is repeated three times or more by the following measuring method for the core wrap sheet. In this case, the liquid permeation time from the first time to the third time is 60 seconds or less.
- an absorbent article that is excellent in liquid permeability, has little liquid residue, hardly causes liquid return, and can be manufactured stably and inexpensively by a relatively simple process.
- FIG. 1 is a view showing a disposable diaper which is an embodiment of the absorbent article of the present invention, and schematically shows a state where the elastic member of each part is stretched and expanded in a planar shape (surface sheet)
- FIG. 2 is a cross-sectional view schematically showing a cross section taken along the line II (cross section along the width direction) of FIG.
- FIG. 3 is an explanatory diagram of a method for measuring the liquid permeation time.
- FIG. 4 is a perspective view schematically showing an enlarged part of another embodiment of the topsheet according to the present invention.
- FIG. 5 is a cross-sectional view schematically showing a part of a cross section along the width direction of the absorbent article of the present invention provided with the surface sheet shown in FIG. 4.
- FIG. 6 (a) is a perspective view showing another embodiment of the absorbent core according to the present invention
- FIG. 6 (b) is a sectional view taken along line II-II (cross section in the width direction) of FIG. 6 (a). It is sectional drawing which shows typically the state reversed.
- the present invention relates to an absorbent article that is excellent in liquid permeability, has little liquid residue, hardly causes liquid return, and can be manufactured stably and inexpensively by a relatively simple process.
- the diaper 1 of this embodiment is a so-called unfolded disposable diaper.
- the liquid-permeable surface sheet 2, liquid-impermeable or water-repellent hereinafter collectively referred to as these.
- the back sheet 3 (referred to as liquid permeation) and the absorbent body 4 disposed between both sheets 2 and 3 are provided, and the intermediate layer 5 is disposed between the top sheet 2 and the absorbent body 4.
- the diaper 1 will be further described.
- the diaper 1 is disposed between a liquid permeable top sheet 2 that forms a skin facing surface, a liquid permeable back sheet 3 that forms a non-skin facing surface, and both sheets 2 and 3.
- the absorbent body 4 is provided and formed substantially vertically long.
- Each of the top sheet 2, the back sheet 3, and the absorber 4 has a vertically long shape that is long in one direction X.
- Each of the top sheet 2 and the back sheet 3 has a size larger than that of the absorber 4, and extends outward from the peripheral edge of the absorber 4.
- the surface sheet 2 has a width direction Y dimension that is smaller than the width direction Y dimension of the back sheet 3.
- the diaper 1 has, in the longitudinal direction X, a back side portion A disposed on the back side of the wearer at the time of wearing, and a ventral side portion B disposed on the abdomen side of the wearer at the time of wearing, And a crotch part C on which the wearer's crotch is arranged when worn.
- the crotch part C includes an excretion part facing part that is disposed so as to face the wearer's excretion part when worn, and is located at the central part in the longitudinal direction X of the diaper 1.
- the back side part A, the ventral side part B, and the crotch part C are each area
- a longitudinal direction is a direction along the long side of an absorptive article (diaper 1) or its component (surface sheet 2, absorptive core 40, etc.), and a width direction ( Y direction in the figure) is a direction orthogonal to the longitudinal direction.
- the skin facing surface is a surface of the absorbent article or a component thereof that is directed to the wearer's skin when the absorbent article is worn, and the non-skin facing surface is an absorption in the absorbent article or a component thereof. It is a surface that is directed to the side opposite to the skin side (clothing side) when wearing the property article.
- extension state by one side edge part is distribute
- a pair of three-dimensional gathers are formed in the crotch part C at the time.
- elastic members 72 are disposed along the longitudinal direction X on the left and right leg portions arranged around the wearer's legs. Leg gathers are formed.
- the pair of side sheets 7, 7, the top sheet 2, the absorber 4, the elastic members 71, 72, and the back sheet 3 are appropriately joined to each other by a known joining means such as a hot-melt adhesive.
- a pair of stretchable panels 8 and 8 are provided on both side edges along the longitudinal direction X of the back side A of the diaper 1, and the length of the ventral side B of the diaper 1
- a pair of panel members 9 and 9 are provided on both side edges along the direction X.
- Each of the stretchable panel 8 and the panel material 9 has an inner edge along the longitudinal direction X fixed to the non-skin facing surface of the back sheet 3 or fixed between the side sheet 7 and the back sheet 3. This fixing is performed by a known joining means such as an adhesive or heat seal.
- a fastening tape 81 to which a fastening portion (not shown) made of a male member of a mechanical surface fastener is attached is attached to each of the pair of stretchable panels 8 and 8.
- a non-skin facing surface of the ventral side B of the diaper 1 is formed with a to-be-attached region 82 made of a female member of a mechanical surface fastener.
- the to-be-attached region 82 is formed by joining and fixing a female member of a mechanical surface fastener to the non-skin facing surface of the back sheet 3 with a known joining means (for example, an adhesive or heat seal).
- the fastening portion of the tape 81 can be detachably fastened.
- the absorbent body 4 covers the absorbent core 40 containing the absorbent material and at least the skin-facing surface of the absorbent core 40 (the surface facing the intermediate layer 5).
- seat 41 containing a hydrophilic nonwoven fabric is comprised.
- the core wrap sheet 41 and the absorbent core 40 may be joined by a known joining means such as a hot melt adhesive.
- the absorbent core 40 has a thin plate shape that is long in one direction (longitudinal direction X of the diaper 1), and a central portion in the longitudinal direction X is constricted.
- the absorbent core 40 contains, as an absorbent material, natural cellulose fibers such as wood pulp, fiber materials such as hydrophilic synthetic fibers, and a water-absorbing polymer.
- natural cellulose fibers such as wood pulp
- fiber materials such as hydrophilic synthetic fibers
- a water-absorbing polymer As the water-absorbing polymer, various polymers conventionally used in the technical field can be used.
- the shape of the water-absorbing polymer is usually particulate, but may be fibrous.
- the core wrap sheet 41 has a width that is two to three times as long as the length of the absorbent core 40 in the width direction Y. The entire area of each non-skin facing surface on the opposite side is covered.
- the absorbent body 4 has the absorbent core 40 placed on the central portion in the width direction Y of the single core wrap sheet 41, and both side portions in the width direction Y are folded back to the upper surface side of the absorbent core 40.
- the edge portions are joined to each other by a known joining means such as a hot melt adhesive to form the core wrap sheet 41 in a cylindrical shape, and obtained by turning upside down.
- the intermediate layer 5 is a layer separated from the absorber 4 and interposed between the top sheet 2 and the absorber 4.
- the intermediate layer 5 and the top sheet 2 and the absorbent body 4 (core wrap sheet 41) are respectively joined to the whole surface or a part by an adhesive.
- the intermediate layer 5 preferably covers 20% or more, particularly 30% or more of the skin facing surface (surface on the surface sheet 2 side) of the absorbent body 4.
- the upper limit of the coverage of the skin 4 of the absorbent body 4 by the intermediate layer 5 is preferably 80%, particularly preferably 60%, and the range of the coverage is preferably 20 to 80%, more preferably Is 30-60%.
- the intermediate layer 5 preferably hangs at the center in the longitudinal direction X of the absorber 4 (intersection of the bisector in the longitudinal direction X of the absorber 4 and the bisector in the width direction Y),
- the center in the longitudinal direction X of the intermediate layer 5 is more preferably located closer to the ventral side B with respect to the bisector of the absorbent body 4 in the longitudinal direction X.
- the intermediate layer 5 satisfies these requirements.
- the intermediate layer 5 has a shorter length (width) in the width direction Y than the absorber 4 (see FIG. 2).
- the side edge along the longitudinal direction X of the intermediate layer 5 is preferably located on the inner side in the range of 5 mm or more and 20 mm or less than the side edge along the longitudinal direction X of the absorber 4. If the width of the intermediate layer 5 extends over the entire width of the absorber 4, it is not preferable because side leakage is likely to occur. Further, the intermediate layer 5 has a shorter length in the longitudinal direction X than the absorber 4.
- the edge along the width direction Y of the intermediate layer 5 is preferably located at least 5 mm inside the edge along the width direction Y of the absorber 4. If the length in the longitudinal direction X of the intermediate layer 5 extends over the entire length of the absorbent body 4, leakage in the longitudinal direction X tends to occur, which is not preferable.
- the intermediate layer 5 includes a cross-linked cellulose fiber, and is preferably a pile of fiber materials including the cross-linked cellulose fiber.
- Cross-linked cellulose fiber is a fiber material formed by cross-linking cellulose molecules or between molecules with a cross-linking agent, and is a hydrophilic fiber. It has characteristics such that the settling is difficult to occur and the crosslinked cellulose fiber itself absorbs a body fluid and hardly swells.
- the absorption space for temporarily storing the body fluid in the intermediate layer 5 is always stabilized, and the liquid permeation speed increases from the top sheet 2 side to the back sheet 3 side, and the liquid residue hardly occurs. Etc. are produced.
- the crosslinked cellulose fiber will be described.
- the cross-linked cellulose fiber is preferably cross-linked both within and between the cellulose fiber molecules.
- the cellulose fiber used as a material for the crosslinked cellulose fiber include natural cellulose fibers such as wood pulp and cotton, regenerated cellulose fibers such as rayon, cupra, tencel, and lyocell, semi-synthetic cellulose fibers such as acetate, and the like.
- Examples of the cellulose fiber crosslinking agent used in the production process of the crosslinked cellulose fiber include N-methylol compounds such as dimethylolethyleneurea and dimethyloldihydroxyethyleneurea; citric acid, tricarballylic acid, butanetetracarboxylic acid, etc. Polycarboxylic acid; polyglycidyl ether compounds and the like, and one kind of them can be used alone or two or more kinds can be used in combination.
- the usage-amount of a crosslinking agent shall be 0.2 to 20 mass parts with respect to 100 mass parts of cellulose fibers. If the amount is less than 0.2 parts by mass, the crosslink density is low, so that the elastic modulus when wet of the crosslinked cellulose fibers is low, and twist / sag may occur. If the amount exceeds 20 parts by mass, the crosslinked cellulose fibers become rigid. When too much stress is applied, the fibers may become brittle. Examples of the method for crosslinking cellulose fibers using a crosslinking agent include the following methods i) and ii).
- Cellulose fibers are impregnated with an aqueous solution of a crosslinking agent, if necessary, and a cellulose fiber is impregnated.
- the cellulose fibers are dehydrated so that the amount of the crosslinking agent aqueous solution reaches a designed adhesion amount, and then heated to a crosslinking temperature.
- Method. ii) A method in which an aqueous solution of a crosslinking agent is sprayed on cellulose fibers so as to have a design adhesion amount by spraying, and then the cellulose fibers are heated to a crosslinking temperature to cause a crosslinking reaction.
- a mercerized crosslinked pulp obtained by further crosslinking a mercerized pulp having a roundness of 0.5 or more obtained by subjecting a normal pulp fiber to a mercerization treatment is preferably used.
- mercerized crosslinked pulp may be obtained by mercerizing cellulose fibers such as wood pulp and increasing the roundness of the cross section, followed by crosslinking treatment, or obtaining commercially available mercerized pulp and crosslinking it. It may be used.
- the crosslinked cellulose fiber those described in Patent Document 2 can also be used.
- the intermediate layer 5 can contain a fiber material other than the crosslinked cellulose fiber.
- other fiber materials that can be contained in the mid layer 5 include natural cellulose fibers such as wood pulp such as softwood kraft pulp (NBKP) and hardwood kraft pulp (LBKP), and non-wood pulp such as cotton pulp and straw pulp; Regenerated cellulose fibers such as cupra; hydrophilic synthetic fibers such as polyvinyl alcohol fibers and polyacrylonitrile fibers; synthetic fibers such as polyethylene terephthalate (PET) fibers, polyethylene (PE) fibers, polypropylene (PP) fibers, and polyester fibers are surface-active. Examples include those subjected to a hydrophilic treatment with an agent, and one of these can be used alone or two or more of them can be used in combination.
- the basis weight of the fiber material (all fiber materials including crosslinked cellulose fibers) in the mid layer 5 is preferably 0.5 times or more, more preferably 1.0 times the basis weight of the fiber material in the absorbent core 40. Above, and preferably 3 times or less, more preferably 2.5 times or less, more specifically 0.5 to 3 times, and even more preferably 1.0 to 2.5 times.
- (basis weight of the fiber material in the intermediate layer 5 / basis weight of the fiber material in the absorbent core 40) is in the range of 0.5 to 3, the liquid absorption rate is further improved. Moreover, the liquid return from the intermediate layer 5 is more effectively prevented.
- the basis weight of the fiber material (all fiber materials including cross-linked cellulose fibers) in the mid layer 5 is preferably 50 g / m 2 or more, more preferably 100 g / m 2 or more, and preferably 300 g / m 2 or less. It is preferably 250 g / m 2 or less, more specifically, preferably 50 to 300 g / m 2 , and more preferably 100 to 250 g / m 2 .
- the core wrap sheet 41 is difficult to decrease in hydrophilicity even when body fluid such as urine is repeatedly discharged and absorbed during use of the diaper 1, and is high during use of the diaper 1.
- transmission speed) over a long time namely, it has durable hydrophilic property
- the liquid permeation times from the first to the third time are all 60 seconds or less, more preferably 50 seconds. Hereinafter, it is particularly preferably 45 seconds or less.
- the lower limit of the liquid permeation time is preferably 5 seconds or more, more preferably 0 seconds or more, which is the time required for pouring 40 g of artificial urine in the following measurement method.
- the liquid permeation time is an index of the liquid permeation speed. The shorter the liquid permeation time, the faster the liquid permeation speed is considered, and the liquid permeation time is highly evaluated as being excellent in liquid permeability. Moreover, it is considered that durability hydrophilicity is excellent, so that the frequency
- the specific paper and specific hydrophilic non-woven fabric described later, which are embodiments of the core wrap sheet 41 there are those in which the liquid permeation time from the first to the fifth time is 60 seconds or less.
- the upper and lower cylinders 91 and 92 are connected by fitting the clip 93 to an annular flange portion provided at the lower end of the upper cylinder 91 and the upper end of the lower cylinder 92.
- Reference numeral 94 denotes a rubber packing having a through hole having the same diameter and the same shape as the inner diameters of the cylinders 91 and 92.
- the filter paper used in the measurement is a filter paper having a retention particle diameter of 1 to 7 ⁇ m according to the filter paper standard. It can be appropriately selected from 1, 4, 6, and 7.
- composition of artificial urine used for measuring the liquid permeation time is as follows. 1.94% by mass of urea, 0.7954% by mass of sodium chloride, 0.11058% by mass of magnesium sulfate (septahydrate), 0.06208% by mass of calcium chloride (dihydrate), 0.19788% by mass of potassium sulfate , Polyoxyethylene lauryl ether 0.0035 mass% and ion-exchanged water (remaining amount).
- the core wrap sheet 41 Since the core wrap sheet 41 has durable hydrophilic properties, even if the body fluid is repeatedly discharged and absorbed during use of the diaper 1, the level of liquid permeability from the core wrap sheet 41 to the absorbent core 40 is high.
- the remaining liquid in 5 [hydrophilic fibers (crosslinked cellulose fibers) constituting the intermediate layer 5] is effectively reduced.
- seat 41 With the high liquid permeability of the core wrap sheet
- the diaper 1 has excellent liquid permeability, high liquid permeation / absorption speed, liquid remaining and liquid return due to the synergistic effect of the intermediate layer 5 containing crosslinked cellulose fibers and the core wrap sheet 41 having durable hydrophilicity. It is difficult.
- paper having hydrophilic durability or hydrophilic nonwoven fabric can be used, and specifically, the following specific paper or specific hydrophilic nonwoven fabric can be used.
- specific paper and the specific hydrophilic nonwoven fabric will be described in order.
- the specific paper is mainly composed of soft kraft bleached kraft pulp having a freeness of 400 to 550 ml, and two or more kinds of paper strength enhancers are added, the basis weight is 10 to 14.5 g / m 2 , and the density is 0.05. ⁇ 0.2g / cm 3, is a crepe rate of 5 to 30%.
- the specific absorbent paper will be described.
- Specified paper contains conifer bleached kraft pulp (NBKP) having a freeness of 400 to 550 ml as an essential component.
- the freeness is preferably 475 ml or more, more preferably 490 ml or more, and preferably 525 ml or less, more preferably 510 ml or less, more specifically preferably 475 to 525 ml, more preferably 490 to 510 ml.
- Freeness is a value indicated by Canadian Standard Freeness (CSF) specified in JIS P8121, and is a value of pulp beating (a process of mechanically tapping and grinding pulp in the presence of water). It is a value indicating the degree.
- CSF Canadian Standard Freeness
- NBKP beating can be carried out according to a conventional method using a known beating machine such as a beader or a disc refiner with respect to a stock (slurry) in which NBKP is dispersed.
- a known beating machine such as a beader or a disc refiner with respect to a stock (slurry) in which NBKP is dispersed.
- the smaller the freeness value the stronger the degree of beating, the greater the damage of the fibers due to beating, and the more fibrillation proceeds.
- NBKP having a freeness in the above range is easily entangled with each other because fibrillation is in progress. Therefore, from the viewpoint of improving liquid permeability, the weight of the thin paper can be reduced (low density) to reduce the weight of the constituent fibers.
- the specific paper mainly composed of NBKP having a freeness of 400 to 550 ml can have good strength characteristics.
- Specified paper is mainly NBKP with a freeness of 400-550 ml.
- “mainly” means that the content of NBKP having a freeness in such a range is 50% by mass or more.
- the content is preferably 50% by mass or more, more preferably 80% by mass or more, and preferably 100% by mass or less, more specifically, preferably 50 to 100% by mass from the viewpoint of obtaining good strength characteristics.
- % More preferably 80 to 100% by mass.
- the fiber roughness of NBKP used for the specific paper is preferably 0.1 mg / m or more, more preferably 0.12 mg / m or more, and preferably 0.2 mg / m or less, more preferably 0.18 mg / m or less. More specifically, it is preferably 0.1 to 0.2 mg / m, and more preferably 0.12 to 0.18 mg / m.
- the fiber roughness is used as a scale representing the fiber thickness in a fiber having a nonuniform fiber thickness, such as wood pulp.
- the average fiber length of NBKP used for the specific paper is preferably 1 mm or more, more preferably 2 mm or more, and preferably 4 mm or less, more preferably 3 mm or less, more specifically preferably 1 to 4 mm, It is preferably 2 to 3 mm.
- the fiber roughness and average fiber length are each measured as follows.
- the fiber (pulp) to be measured shall be unbeaten.
- the fiber is dried in a vacuum dryer at 100 ° C. for 1 hour to remove moisture present in the fiber. 1 g is accurately weighed from the fibers thus dried (error ⁇ 0.1 mg).
- the weighed fibers are completely disaggregated in 150 ml of water with the mixer attached to the fiber roughness meter, and this is until the total amount reaches 5000 ml.
- the specific paper may contain fibers other than NBKP, and the other fibers may not be hydrophilic cellulose fibers such as NBKP.
- Other fibers include, for example, hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), thermomechanical pulp (TMP) and other wood pulp; Non-wood pulp such as kenaf and hemp; synthetic fibers such as polyester fiber, rayon fiber, acrylic fiber, and the like.
- the content of these other fibers is preferably 50% by mass or less.
- paper strength enhancers include dry paper strength enhancers that improve dry paper strength and wet paper strength enhancers that improve wet paper strength.
- Two or more types of paper strength enhancers include dry paper strength enhancers. It is possible to select two or more types from either one of the agent and the wet paper strength enhancer, but from the viewpoint of obtaining particularly excellent strength characteristics, one or more of the dry paper strength enhancer and the wet paper strength enhancer It is preferable to use a combination with one or more.
- dry paper strength enhancer conventionally known dry paper strength enhancers can be used.
- CMC carboxymethyl cellulose
- PVA polyvinyl alcohol
- PAM polyvinyl alcohol
- the salt of CMC or polyacrylamide resin sodium salt is mainly used.
- the polyacrylamide resin include cationic or anionic polyacrylamide (PAM).
- PAM anionic polyacrylamide
- wet paper strength enhancer a conventionally known wet paper strength enhancer can be used.
- epoxidized polyamide polyamine resin PAE
- urea-formalin resin urea-formalin resin
- melamine-formalin resin dialdehyde starch
- polyethyleneamine examples include methylolated polyamide, and one of these can be used alone or two or more of them can be used in combination.
- PAE is particularly preferable.
- a particularly preferable combination of the paper strength enhancers in the specific paper is two dry paper strength enhancers and one wet paper strength enhancer.
- CMC salts and anionic PAM salts are preferred as the two dry paper strength enhancers
- PAE is preferred as the one wet strength agent.
- the total addition amount of the two or more kinds of paper strength enhancers in the specific paper is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, based on the dry mass of all the constituent fibers of the specific paper, and , Preferably 1.5% by mass or less, more preferably 1.2% by mass or less, more specifically preferably 0.01 to 1.5% by mass, and still more preferably 0.03 to 1.2% by mass. It is. If the total amount of the paper strength enhancer is too small, sufficient strength properties such as tensile strength cannot be obtained. If the total amount of the paper strength enhancer is too large, the specific paper is hardened (decrease in texture). There is a possibility that the formation of the specific paper may be reduced due to the sticking of the paper to the Yankee dryer or the adhesion of the paper strength enhancer to the mesh drum during the production of the specific paper.
- Specified paper may contain components other than the above-described fibers such as NBKP and paper strength enhancers.
- fillers such as talc, dyes, color pigments, antibacterial agents, pH adjusters, yield improvers, water resistance agents, antifoaming agents and the like are generally used as raw materials for papermaking and additives. These can be used, and one of these can be used alone or in combination of two or more.
- Specified paper can be produced by a known wet papermaking method.
- the wet papermaking method includes a stock preparation step for preparing a stock (slurry) made of an aqueous dispersion of fibers such as NBKP, and a paper making step for drying while transporting a fiber made from the stock into a fiber web. It is what has.
- the paper making process is usually divided into a wire part, a press part, a dryer part, a size press, a calendar part, etc., and is carried out sequentially.
- the above-mentioned dry paper strength enhancer and wet paper strength enhancer are usually added to the stock in the stock preparation step.
- the wet paper strength enhancer and the dry paper strength enhancer are added in the order of the paper strength enhancer, but the order of addition of the paper strength enhancer in the present invention is not limited to this, and the order of addition may be reversed. Both may be added simultaneously.
- the wet papermaking method can be carried out according to a conventional method using a paper machine such as a long paper machine, a twin wire paper machine, an on-top paper machine, a hybrid paper machine, or a round paper machine.
- the specific paper has a relatively low basis weight and density from the viewpoint of improving liquid permeability.
- the basis weight of the specific paper is preferably 10 g / m 2 or more, more preferably 11 g / m 2 or more, and preferably 14.5 g / m 2 or less, more preferably 14 g / m 2 or less. More specifically, it is preferably 10 to 14.5 g / m 2 , and more preferably 11 to 14 g / m 2 .
- the density of a particular sheet is preferably 0.05 g / cm 3 or more, more preferably 0.1 g / cm 3 or more, and preferably 0.2 g / cm 3 or less, more preferably 0.2 g / cm 3
- it is preferably 0.05 to 0.2 g / cm 3 , more preferably 0.1 to 0.2 g / cm 3 .
- NBKP having a freeness in a specific range is used and two or more paper strength enhancers are used in combination. In this way, such concerns are dispelled.
- the basis weight of the specific paper is less than 10 g / m 2 or the density is less than 0.05 g / cm 3 , the paper strength may be significantly reduced, and the basis weight of the specific paper is more than 14.5 g / m 2 or density. If it exceeds 0.2 g / cm 3 , the effect of improving the liquid permeability may be poor.
- the basis weight of the specific paper is measured as follows. After conditioning the sample (special paper) under the conditions of JIS P8111, a 10 cm square (100 cm 2 area) measurement piece was cut out from the sample, and the weight of the measurement piece was measured with a two-digit balance below the decimal point. Then, the basis weight of the measurement piece is calculated by dividing the measured value by the area. About 10 measurement pieces cut out from the sample, the basis weight is calculated according to the above procedure, and the average value thereof is taken as the basis weight of the sample.
- the density of the specific paper is measured as follows. Ten samples of 20 cm square (special paper) are stacked to form a laminated body, and after cooling and solidifying the laminated body with liquid nitrogen, the vicinity of the center of the laminated body is cut with a cutter. Then, of the 10 samples, one having no shear applied to the cross section generated by cutting with the cutter is selected, and the thickness of the selected sample is measured with an optical microscope. In addition, the thickness of the sample is not the length (apparent thickness) from the bottom to the top of the concavo-convex part when the sample has concavo-convex parts such as crepes described later, but the part where the constituent fibers are deposited Length (substantial thickness).
- the weight W of the 20 cm square sample whose thickness has been measured in this way is measured using a balance with two decimal places.
- the target density is calculated by dividing the weight W of the sample by the volume V of the sample calculated by the following equation (that is, by W / V).
- T is the thickness (cm) of the sample
- A is the crepe rate (%) of the sample
- B is the length of one side (20 cm) of the sample.
- V ⁇ T ⁇ B ⁇ B ⁇ (100 + A) / 100 ⁇
- Specified paper has crepes (crepe-like wrinkles), and the crepe rate is set to 5 to 30%.
- the crepe in the specific paper is preferably a dry crepe that is generated when a dry fiber web (specific paper) is peeled off from a Yankee dryer or the like in the dryer part with a doctor knife or the like.
- the crepe rate is measured as follows.
- ⁇ Measurement method of crepe rate> A rectangular shape having a length of 200 mm in the length direction (conveying direction when producing the specific paper, MD) and a width of 100 mm in the width direction (direction perpendicular to the MD, CD) is cut out from the measurement target sheet (specific paper).
- Crepe rate of the specific paper calculated by the above formula is 10%.
- the paper having the crepe has higher liquid permeability than the paper having no crepe, and the liquid permeability increases as the crepe rate increases.
- the strength properties tensile strength
- the crepe rate of the specific paper is set to 5 to 30% from the viewpoint of the balance between liquid permeability and strength characteristics.
- the crepe rate of the specific paper is preferably 5% or more, more preferably 7% or more, and preferably 20% or less, more preferably 15% or less, more specifically, preferably 5 to 20%, more preferably Is 7 to 15%.
- the specific hydrophilic non-woven fabric includes a hydrophilizing agent kneaded synthetic fiber using a synthetic resin kneaded with a hydrophilizing agent in advance as a fiber raw material. That is, the hydrophilizing agent-kneaded synthetic fiber is obtained through a process of molding a synthetic resin preliminarily kneaded with a hydrophilizing agent into a fiber. It is different from “obtained by applying a hydrophilizing agent to the surface of the fiber by spraying / coating”.
- the synthetic fiber kneaded with a hydrophilizing agent has a feature that even if a body fluid such as urine is repeatedly applied, the hydrophilizing agent hardly flows out to the outside and the hydrophilicity is not easily lowered.
- hydrophilizing agent various known ones can be used without particular limitation, and for example, a hydrophilic oil agent is used.
- the hydrophilic oil agent is generally an anionic, cationic, amphoteric or nonionic surfactant, but is not particularly limited thereto. These can be used in the form of an aqueous solution or emulsion having a predetermined concentration.
- Preferred hydrophilizing agents include, for example, aliphatic monocarboxylates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl phosphates, glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, Fatty acid polyethylene glycol, alkylamine salt, alkylbetaine, etc. are mentioned, These 1 type can be used individually or in combination of 2 or more types.
- the hydrophilizing agent kneading type synthetic fiber may be a single fiber made of a blended polymer obtained by mixing one kind of synthetic resin or two or more kinds of synthetic resins, or may be a composite fiber.
- the composite fiber here is a synthetic fiber obtained by combining two or more kinds of synthetic resins having different components with a spinneret and simultaneously spinning them, and a single fiber having a structure in which a plurality of components are continuous in the length direction of the fiber. It is the thing which mutually adheres inside.
- the form of the composite fiber includes a core-sheath type and a side-by-side type, and is not particularly limited.
- the form of the specific hydrophilic nonwoven fabric is not particularly limited, and for example, a single layer such as an air-through nonwoven fabric, heat roll nonwoven fabric, spunbond nonwoven fabric, resin bond nonwoven fabric, needle punch nonwoven fabric, spunlace nonwoven fabric, airlaid nonwoven fabric, etc. Nonwoven fabric may be mentioned.
- the basis weight of the specific hydrophilic nonwoven fabric is preferably 5 g / m 2 or more, more preferably 10 g / m 2 or more, and preferably 30 g / m 2 or less, more preferably 20 g / m 2 or less, more specifically It is preferably 5 to 30 g / m 2 , more preferably 10 to 20 g / m 2 .
- the core wrap sheet 41 may further include other nonwoven fabric (for example, a normal nonwoven fabric having no hydrophilicity) in addition to the specific hydrophilic nonwoven fabric.
- the specific hydrophilic nonwoven fabric and the other nonwoven fabric may be laminated and integrated.
- the core wrap sheet 41 using the specific hydrophilic nonwoven fabric from SMS nonwoven fabric (spunbond nonwoven fabric (layer), meltblown nonwoven fabric (layer), spunbond nonwoven fabric (layer) laminated and integrated in this order) And the spunbond nonwoven fabric (layer) forming at least one surface of the nonwoven fabric is a specific hydrophilic nonwoven fabric (kneaded with a hydrophilizing agent, using a synthetic resin pre-kneaded with a hydrophilizing agent as a fiber raw material) Type synthetic fibers).
- SMS nonwoven fabric spunbond nonwoven fabric (layer), meltblown nonwoven fabric (layer), spunbond nonwoven fabric (layer) laminated and integrated in this order
- the spunbond nonwoven fabric (layer) forming at least one surface of the nonwoven fabric is a specific hydrophilic nonwoven fabric (kneaded with a hydrophilizing agent, using a synthetic resin pre-kneaded with a hydrophilizing agent as a fiber raw material) Type synthetic fibers).
- SMS nonwoven fabric spunbond nonwoven fabric (layer), melt
- the core wrap sheet 41 made of the SMS nonwoven fabric including the specific hydrophilic nonwoven fabric may be mentioned.
- Form A is particularly preferable.
- Form A A form in which each of the spunbond nonwoven fabrics forming both surfaces of the SMS nonwoven fabric is a specific hydrophilic nonwoven fabric.
- Form B A form in which only the spunbond nonwoven fabric forming one surface of the SMS nonwoven fabric is a specific hydrophilic nonwoven fabric.
- the core wrap sheet 41 made of an SMS nonwoven fabric is a diaper so that the spunbond nonwoven fabric, which is a specific hydrophilic nonwoven fabric, forms the skin facing surface of the core wrap sheet 41 (the surface facing the intermediate layer 5). 1 is preferable.
- the SMS nonwoven fabric including the specific hydrophilic nonwoven fabric can have a low basis weight because of its high strength when wet, and has good liquid permeability regardless of whether other layers other than the specific hydrophilic nonwoven fabric are hydrophilized. Have. On the other hand, for the deformation of the absorbent body and the large amount of liquid movement due to the liquid return, since the core wrap sheet 41 has high wet strength, the tearing and tearing due to the deformation of the absorbent body is prevented. In the SMS nonwoven fabric (having a melt blown nonwoven fabric (layer) with a narrow gap), the effect of suppressing rapid liquid movement is maintained.
- the layers other than the specific hydrophilic nonwoven fabric are not hydrophilized, but the layers constituting the SMS nonwoven fabric are laminated in a web state and the layers are in close contact with each other.
- a part of the hydrophilizing agent that has come out on the fiber surface of the specific hydrophilic nonwoven fabric moves to the fiber surface of the other layer, and the other layer becomes It is considered that the liquid becomes hydrophilic and the liquid permeability is further enhanced.
- the basis weight of the SMS nonwoven fabric including the specific hydrophilic nonwoven fabric is preferably 5 g / m 2 or more, more preferably 8 g / m 2 or more, from the viewpoint of having high liquid permeability while having sufficient strength when wet, and It is preferably 30 g / m 2 or less, more preferably 20 g / m 2 or less, more specifically preferably 5 to 30 g / m 2 , more preferably 8 to 20 g / m 2 .
- the strength of the SMS nonwoven fabric including the specific hydrophilic nonwoven fabric is preferably 2N or more, more preferably 3N or more. Wet strength is measured as follows.
- Measurement method of wet strength 200 mm in the longitudinal direction of the absorbent article from the measurement target sheet (core wrap sheet) (conveying direction when producing the measurement target sheet, MD), and 50 mm in the width direction of the absorbent article (direction perpendicular to MD, CD) Cut out a rectangular measurement piece, immerse the measurement piece in the water of a bat filled with water to sufficiently contain moisture, and lightly sandwich the measurement piece with a water absorbent material such as a paper towel to remove excess moisture. After removal, a measurement sample was prepared.
- the measurement sample is attached to a chuck of a tensile tester (for example, Tensilon tensile tester “RTA-100” manufactured by Orientec Co., Ltd.) with a distance between chucks of 150 mm so that its longitudinal direction (MD) is a tensile direction. Then, the measurement sample is pulled at a tensile speed of 300 mm / min, and the maximum load point (breaking strength) until the measurement sample breaks is defined as the wet strength of the measurement sample.
- a tensile tester for example, Tensilon tensile tester “RTA-100” manufactured by Orientec Co., Ltd.
- a liquid-permeable sublayer sheet 6 is disposed between the top sheet 2 and the intermediate layer 5.
- the liquid-permeable sublayer sheet 6 is a single sheet made of paper, nonwoven fabric, or the like that is separate from the absorber 4 and the intermediate layer 5, and is also referred to as a sublayer.
- the liquid-permeable sublayer sheet 6 is effective in reducing so-called liquid return in which the liquid absorbed by the absorber returns to the top sheet.
- the liquid-permeable sublayer sheet 6 is disposed on the crotch part C where at least the excretory part facing part exists. In this embodiment, as shown in FIG.
- the liquid-permeable sublayer sheet 6 has a rectangular shape in plan view, like the intermediate layer 5, but is longer and longer in the width direction Y than the intermediate layer 5.
- the liquid permeable sublayer sheet 6 and the surface sheet 2 and the intermediate layer 5 are bonded to each other entirely or partially by an adhesive.
- liquid-permeable sublayer sheet 6 examples include paper obtained by wet papermaking; non-woven fabrics manufactured by the card method, air-through non-woven fabrics, resin-bonded non-woven fabrics, spunbond non-woven fabrics, meltblown non-woven fabrics, spunlace nonwoven fabrics, needle punched non-woven fabrics, etc.
- Various non-woven fabrics can be used. These nonwoven fabrics may be subjected to a hydrophilic treatment using a hydrophilic agent such as a surfactant.
- the basis weight of the liquid-permeable sublayer sheet 6 is preferably 20 g / m 2 or more, more preferably 30 g / m 2 or more, and preferably 70 g / m 2 or less, more preferably 50 g / m 2 or less, more specifically Specifically, it is preferably 20 to 70 g / m 2 , more preferably 30 to 50 g / m 2 .
- a liquid-permeable sheet conventionally used in the technical field can be used.
- a nonwoven fabric, an air-through nonwoven fabric, a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric, and the like manufactured by the card method
- Various nonwoven fabrics such as needle punched nonwoven fabrics; films that can be permeated by opening means, and the like.
- These nonwoven fabrics and films may be subjected to a hydrophilic treatment using a hydrophilic agent such as a surfactant.
- the basis weight of the top sheet 2 is preferably 10 g / m 2 or more, more preferably 15 g / m 2 or more, and preferably 60 g / m 2 or less, more preferably 50 g, from the viewpoints of cost, production, and absorption performance.
- / M 2 or less more specifically, preferably 10 to 60 g / m 2 , more preferably 15 to 50 g / m 2 .
- the surface sheet 2 is a structural member that comes into contact with the skin of the wearer of the diaper 1, and when petrolatum is attached thereto, a skin care effect can be expected. In particular, it is effective when petrolatum is adhered to the skin facing surface side of the top sheet 2.
- petrolatum those used for humectants and skin care applications can be used without particular limitation.
- Examples of the method for adhering petrolatum to the top sheet include a method of applying or spraying the petrolatum solution obtained by dissolving petrolatum in a suitable solvent onto the top sheet.
- the adhesion amount of the petrolatum solution on the top sheet is preferably 5 g / m 2 or more, more preferably 10 g / m 2 or more, and preferably 30 g / m 2 or less, more preferably 20 g / m 2 or less, in terms of solid content. More specifically, it is preferably 5 to 30 g / m 2 , more preferably 10 to 20 g / m 2 .
- the back sheet 3 examples include various liquids such as a resin film having no moisture permeability, a resin film having fine pores and moisture permeability, a nonwoven fabric such as a water-repellent nonwoven fabric, and a laminate of these and other sheets.
- An impermeable or water-repellent material can be used.
- the side sheet 7 the same thing as the back surface sheet 3 can be used.
- the top sheet 2 ⁇ / b> A has a large number of convex portions 21 that protrude toward the wearer's skin and a number of concave portions 22 that are adjacent to the convex portions 21.
- the convex portions 21 and the concave portions 22 are arranged on the skin facing surface 2a of the topsheet 2A that forms the skin facing surface of the diaper 1 so as to be alternately arranged in one direction.
- Such an uneven shape of the skin facing surface 2a of the topsheet 2A by the convex portion 21 and the concave portion 22 is an arrangement region of the absorbent body 4 (at least in the crotch part C (the excretory portion facing portion)) of the diaper 1 as shown in FIG. In a plan view, it is formed in a region overlapping with the absorber 4. The central portion of the diaper 1 in the width direction Y. In this embodiment, the region where the absorber 4 is disposed in each of the back side portion A and the ventral side portion B. Also formed.
- the top sheet 2A is made of a single layer nonwoven fabric. 2 A of surface sheets protrude toward the wearer's skin side in parts other than the recessed part 22, and form the convex part 21. FIG. A space 25 in which the material for forming the topsheet 2A does not substantially exist is formed in the convex portion 21.
- the concave portion 22 is substantially flat and has no unevenness, and is in contact with the skin facing surface of the absorbent body 4 (core wrap sheet 41).
- the surface sheet 2A having a concavo-convex structure formed by the convex portions 21 and the concave portions 22 can be formed by using a known embossing process.
- a surface sheet original fabric (a flat sheet having no concavo-convex surface) is formed on the peripheral surface.
- the surface sheet 2 ⁇ / b> A is used instead of the surface sheet 2
- a space 25 is formed in which the convex portion 21 faces the skin side and the material for forming the surface sheet 2 ⁇ / b> A is not substantially present.
- the permeability of the surface sheet 2A is improved, and liquid return is less likely to occur compared to a flat surface sheet having no irregularities on the surface (skin facing surface), and the area of adhesion to the skin is increased.
- the amount of body fluid attached to the skin is reduced, and the effect of improving the dry feeling of the surface (skin facing surface) is exhibited.
- the dimensions and the like of each part of the top sheet 2A are preferably set as follows.
- the height L1 of the convex portion 21 is preferably 0.5 mm or more, more preferably 1 mm or more, and preferably 6 mm or less, more preferably 5 mm or less, more specifically preferably 0.2 mm. It is 5 to 6 mm, more preferably 1 to 5 mm.
- the maximum diameter L2 (see FIG. 5)
- the convex portion 21 is preferably 1 mm or more, more preferably 0.5 mm or more, and preferably 10 mm or less, more preferably 5 mm or less, more specifically preferably 1 to
- the thickness is 10 mm, more preferably 0.5 to 5 mm.
- the absorbent core 40 (flat type absorbent core) which does not have an unevenness
- corrugated shape shown in FIG. 40A can also be used.
- the absorbent core 40 ⁇ / b> A has a high basis weight portion 41 having a relatively large amount of absorbent material and a low basis weight portion 42 having a relatively small amount of absorbent material. 41 and the low basic weight part 42 are alternately formed in the predetermined direction. In the form shown in FIG.
- the high basis weight portions 41 and the low basis weight portions 42 are alternately formed in the longitudinal direction X and the width direction Y, respectively. More specifically, as shown in FIG. 6, the absorbent core 40 ⁇ / b> A includes a linear low basis weight portion 42 ⁇ / b> X extending over the entire length along the longitudinal direction X of the absorbent core 40 ⁇ / b> A, and the absorbent core. A plurality of linear low basis weight portions 42Y extending over the entire length along the width direction Y of 40A are formed, and the low low weight portion 42 is formed in a lattice shape as a whole. A portion partitioned by the amount portions 42X and 42Y is a high basis weight portion 41. Each of the plurality of high basis weight portions 41 has a rectangular shape in plan view.
- the high basis weight portion 41 is thicker than the low basis weight portion 42 (42X, 42Y), and therefore the absorbent core 40A has the high basis weight portion 41 in the low basis weight portion 42. It has an uneven shape that is raised in comparison.
- the absorbent core 40A has a concavo-convex shape, the skin-opposing surface and the non-skin-facing surface are not concavo-convex like the absorbent core 40, as compared to a substantially flat absorbent core.
- the excretory part-facing portion in the crotch part C is easily deformed into a shape that is pressed against the skin of the diaper wearer when the diaper 1 is worn. This improves the comfort of the diaper wearer and effectively prevents leakage of body fluids such as urine.
- the low basis weight portion 42 (42X, 42Y) is unevenly distributed in the thickness direction of the absorbent core 40 in the cross-sectional view of the absorbent core 40A. More specifically, as shown in FIG. 6, the low basic weight part 42 is unevenly distributed on the skin facing surface 40b side in the thickness direction T of the absorbent core 40A. And since the low basic weight part 42 is unevenly distributed in the skin facing surface 40b side in the thickness direction T in this way, the high basic weight part 41 is on the opposite side to the skin facing surface 40b, that is, in the thickness direction T. It protrudes to the non-skin facing surface 40a side.
- the skin facing surface 40b is substantially flat with no unevenness, whereas the non-skin facing surface 40a is formed with a protruding high basis weight portion 41 (convex portion). It has unevenness due to the low basis weight part 42 (non-convex part or concave part) located between the high basis weight parts 41, 41.
- the absorbent core 40 ⁇ / b> A when used instead of the absorbent core 40, the absorbent core 40 ⁇ / b> A has a low basis weight portion 42 and a recess formed corresponding thereto (the material for forming the absorbent core 40 ⁇ / b> A is The non-existent space), the body fluid can be diffused while shortening the body fluid absorption time, and the absorbent core 40A can be used efficiently. Therefore, liquid return is more effectively prevented.
- the ratio (S42 / S41) of the basis weight S41 of the high basis weight portion 41 of the absorbent core 40A and the basis weight S42 of the low basis weight portion 42 is preferably 20% or more, more preferably 30% or more, and preferably Is 80% or less, more preferably 70% or less, more specifically, preferably 20 to 80%, more preferably 30% to 70%.
- the basis weight S41 in high basis weight portion 41 is preferably 300 g / m 2 or more, more preferably 350 g / m 2 or more, and preferably 900 g / m 2 or less, more preferably 800 g / m 2 or less, more specifically Is preferably 300 to 900 g / m 2 , more preferably 350 to 800 g / m 2 .
- the basis weight of S42 low basis weight portion 42 is preferably 100 g / m 2 or more, more preferably 150 g / m 2 or more, and preferably 500 g / m 2 or less, more preferably 400 g / m 2 or less, more specifically Is preferably 100 to 500 g / m 2 , more preferably 150 to 400 g / m 2 .
- the ratio (T42 / T41) between the thickness T41 of the high basis weight portion 41 and the thickness T42 of the low basis weight portion 42 is preferably 30% or more, more preferably 40% or more, and preferably 90% or less, more preferably. Is 80% or less, more specifically, preferably 30 to 90%, more preferably 40 to 80%.
- the thickness T41 of the high basis weight portion 41 is preferably 2 mm or more, more preferably 3 mm or more, and preferably 8 mm or less, more preferably 7 mm or less, more specifically preferably 2 to 8 mm, more preferably 3 ⁇ 7 mm.
- the thickness T42 of the low basis weight portion 42 is preferably 1.5 mm or more, more preferably 2.5 mm or more, and preferably 4.5 mm or less, more preferably 4 mm or less, more specifically preferably 1. It is 5 to 4.5 mm, more preferably 2.5 to 4 mm.
- the ratio of the area of the high basis weight part 41 and the area of the low basis weight part 42 in the absorbent core 40A is adjusted.
- the area of the high basis weight part 41 and the area of the low basis weight part 42 The ratio is preferably 6: 4 to 9: 1, and more preferably 7: 3 to 8: 2.
- the absorbent core 40A having a concavo-convex shape can be manufactured using a known fiber stacking apparatus in the same manner as the method for manufacturing the absorbent core of this type of absorbent article.
- the fiber stacking apparatus usually includes a rotating drum having a concave portion for accumulation on the outer peripheral surface, and supplies the absorbent material to the outer peripheral surface in a scattered state while rotating the rotary drum, and the absorbent material is supplied to the concave portion for collecting.
- the fiber is stacked in the accumulation recess by suction from the bottom surface, and the piled material in the accumulation recess is released from the accumulation recess by suction from the suction means arranged opposite to the accumulation recess. It is a device to transfer on.
- the fiber stacking apparatus having such a configuration, by disposing a non-breathable member or a non-breathable member on a part of the breathable bottom surface of the concave portion for accumulation, etc.
- a non-breathable member or a non-breathable member on a part of the breathable bottom surface of the concave portion for accumulation, etc.
- an absorbent core according to a conventional method using a fiber stacking device including a rotating drum in which a part of the bottom surface of the concave portion for accumulation is a non-permeability portion or a non-breathable portion,
- the portion corresponding to the air-impermeable portion is the low basis weight portion 42 (42X, 42Y), and the portion corresponding to the other portion of the bottom surface is the high basis weight portion 41, so that an absorbent core 40A having an uneven shape is obtained.
- the absorbent core 40 was coat
- the skin opposing surface of the absorbent core 40 is used by using one of the two core wrap sheets. (The surface facing the intermediate layer 5) may be covered, and the other non-skin facing surface (the surface facing the back sheet 3) of the absorbent core 40 may be covered with another sheet.
- the core wrap sheet covering at least the skin facing surface of the absorbent core has a liquid permeation time from the first to the third time of 60 seconds or less in the predetermined liquid permeation time measurement method as described above.
- covers the non-skin opposing surface of an absorptive core does not need to have such durable hydrophilicity, as long as it has such durable hydrophilicity.
- a deployment type disposable diaper was mentioned as one of the application examples of the absorbent article of this invention, in addition to the pants type disposable diaper previously shape
- the absorbent body includes an absorbent core containing an absorbent material, and a core wrap sheet that covers at least the skin-facing surface of the absorbent core and includes paper or a hydrophilic nonwoven fabric, About the said core wrap sheet
- the core wrap sheet is made of a spunbond-meltblown-spunbond non-woven fabric, and a spunbond non-woven fabric forming at least one surface of the non-woven fabric is made from a synthetic resin in which a hydrophilizing agent is previously kneaded.
- the absorbent article according to the above ⁇ 1> comprising a hydrophilizing agent-kneaded synthetic fiber.
- the core wrap sheet has a width that is not less than 2 times and not more than 3 times the length in the width direction of the absorbent core, and the skin of the absorbent core is opposed to one core wrap sheet.
- the core wrap sheet is a specific paper, and the specific paper is mainly composed of softwood bleached kraft pulp having a freeness of 400 to 550 ml, to which two or more kinds of paper strength enhancers are added, and has a basis weight.
- NNKP softwood bleached kraft pulp
- the fiber roughness of NBKP used for the specific paper is 0.1 mg / m or more, more preferably 0.12 mg / m or more, and 0.2 mg / m or less, preferably 0.18 mg / m or less.
- the average fiber length of NBKP used for the specific paper is 1 mm or more, preferably 2 mm or more, and 4 mm or less, preferably 3 mm or less, according to any one of the above ⁇ 4> to ⁇ 6> Absorbent article.
- the paper strength enhancer added to the specific paper is selected from the group consisting of carboxymethyl cellulose (CMC) and salts thereof, polyacrylamide resins and salts thereof, cationized starch, and polyvinyl alcohol (PVA).
- CMC carboxymethyl cellulose
- PVA polyvinyl alcohol
- the absorbent article according to ⁇ 8>, wherein the combination of the paper strength enhancer added to the specific paper is two dry paper strength enhancers and one wet paper strength enhancer.
- the total addition amount of the two or more paper strength enhancers in the specific paper is 0.01% by mass or more, preferably 0.03% by mass or more, based on the dry mass of all the constituent fibers of the specific paper.
- the basis weight of the specific paper is 10 g / m 2 or more, preferably 11 g / m 2 or more, and 14.5 g / m 2 or less. The absorbent article as described.
- ⁇ 12> density of the particular paper, 0.05 g / cm 3 or more, preferably 0.1 g / cm 3 or more, and, 0.2 g / cm 3 or less is the ⁇ 4> to ⁇ 11> either The absorbent article according to one item.
- ⁇ 13> The absorbent article according to any one of ⁇ 4> to ⁇ 12>, wherein the specific paper has a crepe (crepe-like wrinkles), and the crepe rate is 5 to 30%. .
- the SMS nonwoven fabric (a nonwoven fabric obtained by laminating and integrating a spunbond nonwoven fabric, a meltblown nonwoven fabric, and a spunbond nonwoven fabric in this order) is a specific hydrophilic nonwoven fabric that forms at least one surface of the nonwoven fabric.
- the absorbent core has a high basis weight part having a relatively large amount of the absorbent material and a low basis weight part having a relatively small amount of the absorbent material, and the high basis weight part and the low basis weight part.
- the absorbent core contains, as an absorbent material, natural cellulose fibers and / or hydrophilic synthetic fibers (hereinafter referred to as fiber materials) that are wood pulp and a water-absorbing polymer.
- fiber materials natural cellulose fibers and / or hydrophilic synthetic fibers
- the high basis weight portion and the low basis weight portion are alternately formed in the longitudinal direction and the width direction of the absorbent core, More specifically, the absorbent core includes a linear low basis weight portion extending over the entire length along the longitudinal direction of the absorbent core, and the entire length along the width direction of the absorbent core.
- the low basis weight portion is unevenly distributed in the thickness direction of the absorbent core, More specifically, the low basis weight portion is unevenly distributed on the skin-facing surface side in the thickness direction of the absorbent core, and the skin-facing surface is substantially flat with no unevenness, and is not flat on the absorbent core.
- the skin facing surface has irregularities due to the projectingly formed high basis weight part (convex part) and the low basis weight part (non-convex part or recessed part) located between the two high basis weight parts.
- the ratio (S42 / S41) between the basis weight (S41) of the high basis weight part and the basis weight (S42) of the low basis weight part of the absorbent core is 20% or more, preferably 30% or more.
- the basis weight of the high basis weight part is 300 g / m 2 or more, preferably 350 g / m 2 or more, and 900 g / m 2 or less, preferably 800 g / m 2 or less. 20> The absorbent article according to any one of the above.
- ⁇ 22> The absorption according to any one of ⁇ 1> to ⁇ 21>, wherein the basis weight of the fiber material in the intermediate layer is 0.5 to 3 times the basis weight of the fiber material in the absorbent core. Sex goods. ⁇ 23> The absorptivity according to any one of ⁇ 1> to ⁇ 22>, wherein the intermediate layer includes a crosslinked cellulose fiber obtained by crosslinking cellulose molecules or between molecules with a crosslinking agent. Goods. ⁇ 24> The absorbent article according to ⁇ 23>, wherein the crosslinked cellulose fiber is crosslinked both inside and between molecules of the cellulose fiber.
- the basis weight of the fiber material (all fiber materials including the crosslinked cellulose fiber) in the intermediate layer is 0.5 to 3 times the basis weight of the fiber material in the absorbent core, preferably 1.
- the basis weight of the fiber material (all fiber materials including the crosslinked cellulose fiber) in the intermediate layer is 50 g / m 2 or more, preferably 100 g / m 2 or more, and 300 g / m 2 or less, preferably The absorbent article according to any one of ⁇ 22> to ⁇ 26>, wherein the absorbent article is 250 g / m 2 or less.
- the intermediate layer covers any one of the items ⁇ 1> to ⁇ 27>, which covers 20 to 80%, preferably 30 to 60%, of the skin-facing surface (surface on the topsheet side) of the absorbent body An absorbent article according to any one of the above.
- ⁇ 29> The absorbent article according to any one of ⁇ 1> to ⁇ 28>, wherein a liquid-permeable sublayer sheet is disposed between the top sheet and the intermediate layer.
- a liquid-permeable sublayer sheet is disposed between the top sheet and the intermediate layer.
- the liquid-permeable sincerity sublayer sheet is a sheet made of paper or nonwoven fabric, and is arranged so as to cover substantially the entire area of the intermediate layer.
- the liquid permeable sublayer sheet is made of paper obtained by wet papermaking, a nonwoven fabric produced by a card method, an air-through nonwoven fabric, a resin bond nonwoven fabric, a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric, and a needle punched nonwoven fabric.
- the absorbent article according to ⁇ 30> selected from the group consisting of: ⁇ 32>
- the basis weight of the liquid-permeable sublayer sheet is 20 g / m 2 or more, preferably 30 g / m 2 or more, and 70 g / m 2 or less, preferably 50 g / m 2 or less ⁇ 29>
- ⁇ 33> The surface sheet according to any one of ⁇ 1> to ⁇ 32>, wherein the topsheet has a plurality of convex portions protruding toward the skin side of the wearer and a plurality of concave portions adjacent to the convex portions.
- ⁇ 34> The absorbent article according to any one of ⁇ 1> to ⁇ 33>, wherein petrolatum is attached to the top sheet.
- the amount of petrolatum attached to the top sheet is 5 g / m 2 or more, preferably 10 g / m 2 or more, and 30 g / m 2 or less, preferably 20 g / m 2 or less in terms of solid content.
- the back sheet is a resin film having no moisture permeability, a resin film having fine holes and moisture permeability, a water-repellent nonwoven fabric, or a laminate of these and other sheets.
- the absorbent article is disposed on the back side of the wearer at the time of wearing, on the abdominal side of the wearer at the time of wearing, and on the inseam of the wearer at the time of wearing.
- a side sheet in which an elastic member is fixed to one side edge portion in an extended state is disposed on each side portion along the longitudinal direction of the unfolded disposable diaper, and a pair of three-dimensional gathers and a pair
- NBKP [Core wrap sheet A-1]
- NBKP [trade name “Cariboo” (produced in North America, manufactured by Cariboo Pulp and Paper Company) and product name “ARAUCO” (produced in South America, manufactured by ARAUCO), the content ratio of both pulps is 5 / NBKP prepared by mixing so as to be 5) was uniformly dispersed in water to prepare a slurry having a fiber concentration of 2% by mass, and this slurry was passed through a beater to adjust the NBKP freeness to 500 ml.
- the slurry thus obtained was spread on a wire mesh paper wire having a wire opening diameter of 90 ⁇ m (166 mesh), a paper layer was formed on the wire mesh paper wire, and 6 ml / (cm 2 ⁇ sec) was formed using a suction box. After the paper layer was dehydrated at a speed, the paper layer was dried with a dryer, and the paper layer was peeled off from the dry surface with a doctor blade, and a crepe was applied at a speed ratio of the dryer and the winding. The thin paper (crepe paper) thus obtained was used as the core wrap sheet A-1.
- Core wrap sheet A-2 The specific paper was produced by the following procedure, and this was designated as core wrap sheet A-2.
- NBKP manufactured by Cariboo Pulp and Paper Company, trade name “Cariboo”, manufactured in North America, fiber roughness 0.15 mg / m, average fiber length 2.44 mm
- the slurry was passed through a beater to adjust the freeness of NBKP to 500 ml.
- the slurry thus obtained was spread on a wire mesh paper wire having a wire opening diameter of 90 ⁇ m (166 mesh), a paper layer was formed on the wire mesh paper wire, and 6 ml / (cm 2 ⁇ sec) was formed using a suction box. After the paper layer was dehydrated at a speed, the paper layer was dried with a dryer, and the paper layer was peeled off from the dry surface with a doctor blade, and a crepe was applied at a speed ratio of the dryer and the winding.
- the specific paper having a basis weight of 13.5 g / m 2 thus obtained was designated as core wrap sheet A-2.
- SMS nonwoven fabric having a basis weight of 13 g / m 2 was used as a core wrap sheet B.
- This SMS nonwoven fabric (core wrap sheet B) corresponds to the above-mentioned form A, and the spunbond nonwoven fabric forming both surfaces of the SMS nonwoven fabric is the specific hydrophilic nonwoven fabric containing a synthetic fiber mixed with a hydrophilizing agent. It was.
- SMS nonwoven fabric having a basis weight of 13 g / m 2 was used as a core wrap sheet C.
- This SMS nonwoven fabric (core wrap sheet C) corresponds to the form B, and only the spunbond nonwoven fabric forming one surface of the SMS nonwoven fabric is the specific hydrophilic nonwoven fabric containing a hydrophilizing agent-kneaded synthetic fiber. there were.
- seat C it distinguishes further according to the use form, and specifically, the surface (the said specific hydrophilic nonwoven fabric) containing a hydrophilizing agent kneading type synthetic fiber is made into a skin opposing surface (upper side).
- the core wrap sheet C-1 was used as the core wrap sheet C-1, and the surface containing the synthetic fiber containing the hydrophilizing agent (the specific hydrophilic nonwoven fabric) was used as the non-skin facing surface (lower side). 2.
- a core wrap sheet D was obtained by attaching a hydrophilic agent to the surface of a constituent fiber of an SMS nonwoven fabric having a basis weight of 10 g / m 2 equivalent to the use of a commercially available disposable diaper.
- Example 1 An unfolded disposable diaper (M size equivalent) having the same basic configuration as the diaper 1 shown in FIGS. 1 and 2 was produced and used as a sample of Example 1.
- the surface sheet, the liquid-permeable sublayer sheet, and the intermediate layer sheets used as commercially available disposable diapers (manufactured by P & G, trade name “Pampers Cotton Care Tape”) were used.
- middle layer was 100 mass%.
- middle layer was 0.9 times the basic weight of the fiber material in the following absorptive core with a basic weight of about 180 g / m ⁇ 2 >.
- a liquid resin-permeable and moisture-permeable polyethylene resin film (containing calcium carbonate) having a basis weight of 25 g / m 2 was used.
- the absorbent core is a flat absorbent core having substantially no irregularities, in which a fibrous aggregate is held with a particulate water-absorbing polymer (SAP).
- SAP particulate water-absorbing polymer
- the total length of the absorbent core in the longitudinal direction was 370 mm
- the total length in the width direction was 120 mm
- the shape of the absorbent core in plan view was an hourglass shape as shown in FIG.
- the core wrap sheet A-1 was used as the core wrap sheet.
- Example 2 An unfolded disposable diaper was produced in the same manner as in Example 1 except that the core wrap sheet A-2 was used instead of the core wrap sheet A-1, and used as a sample of Example 2.
- Example 3 An unfolded disposable diaper was produced in the same manner as in Example 1 except that the core wrap sheet B was used instead of the core wrap sheet A-1, and used as a sample of Example 3.
- Example 4 An unfolded disposable diaper was produced in the same manner as in Example 1 except that the core wrap sheet C-1 was used in place of the core wrap sheet A-1, and used as a sample of Example 4. That is, in Example 4, the core wrap sheet C is formed so that one spunbond nonwoven fabric, which is a specific hydrophilic nonwoven fabric, forms the skin facing surface (facing the intermediate layer) of the core wrap sheet C. Arranged.
- Example 5 An unfolded disposable diaper was produced in the same manner as in Example 1 except that the core wrap sheet C-2 was used in place of the core wrap sheet A-1, and used as a sample of Example 5. That is, in Example 5, the core wrap sheet C is formed such that one spunbond nonwoven fabric, which is a specific hydrophilic nonwoven fabric, forms the non-skin facing surface (non-facing surface with the intermediate layer) of the core wrap sheet C. Placed in a diaper.
- the core wrap sheet C-2 was used in place of the core wrap sheet A-1, and used as a sample of Example 5. That is, in Example 5, the core wrap sheet C is formed such that one spunbond nonwoven fabric, which is a specific hydrophilic nonwoven fabric, forms the non-skin facing surface (non-facing surface with the intermediate layer) of the core wrap sheet C. Placed in a diaper.
- Example 6 An unfolded disposable diaper was produced in the same manner as in Example 1 except that an uneven absorbent core having substantially the same configuration as the absorbent core 40A shown in FIG. 6 was used as the absorbent core. It was.
- the concavo-convex absorbent core used in Example 6 is a fiber assembly in which a particulate water-absorbing polymer is held. The total length in the longitudinal direction is 370 mm, and the total length in the width direction (maximum length) is 120 mm. The shape in plan view was an hourglass shape. The size of the block of the concavo-convex high basis weight portion was 10 ⁇ 20 mm, and the width of the groove of the low basis weight portion was 2 mm.
- the uneven absorbent core used in Example 6 had a total basis weight average of 466 g / m 2 consisting of a uniform mixture of fluff pulp average of 223 g / m 2 and water-absorbing polymer average of 243 g / m 2, and low basis weight.
- parts are fluff pulp average 152 g / m 2 and the water-absorbing polymer average 105 g / m 2 made from a homogeneous mixture of a total basis weight average 257 g / m 2, a basis of fluff pulp and high basis weight portion and the low basis weight portion
- the weight ratio (high basis weight part / low basis weight part) is 1.5, and the basis weight ratio (high basis weight part / low basis weight part) of the absorbent polymer is 2.3.
- Comparative Example 1 An unfolded disposable diaper was produced in the same manner as in Example 1 except that the core wrap sheet D was used instead of the core wrap sheet A, and a sample of Comparative Example 1 was obtained.
- Comparative Example 2 An unfolded disposable diaper was produced in the same manner as Comparative Example 1 except that fluff pulp having a basis weight of 180 g / m 2 was used as the intermediate layer, and a sample of Comparative Example 2 was obtained.
- the intermediate layer (pulp) used in Comparative Example 2 does not contain cross-linked cellulose fibers, and uses pulp fibers (NBKP 100%) as constituent fibers.
- a square-shaped collagen film product name “COFFI”, manufactured by Naturin
- a load is further applied for 1 minute to form a diaper.
- the absorbed artificial urine was absorbed into the collagen film.
- This collagen film has substantially the same contact angle as human skin.
- the load is 4 kg on a 70 mm x 70 mm square acrylic plate with a circular convex part (diameter 20 mm, height 5 mm) in the center (about 7 kPa: minimum 2 kPa to maximum on a wet diaper after liquid injection) 21 kPa) was added.
- the load was removed, and the weight (g) of the collagen film that absorbed artificial urine was measured.
- the weight of the collagen film before absorption of artificial urine was subtracted from this weight, and the value was defined as the liquid return amount (g) under no pressure.
- the intermediate layer and the liquid-permeable sublayer sheet were taken out from the diaper after the measurement of the liquid return after absorption of artificial urine, and the weight (g) was measured. ) ”Was added, and the value was defined as the remaining amount of the intermediate layer liquid. The smaller the liquid return amount under no pressure and the remaining intermediate layer liquid amount, the higher the evaluation.
- the diaper after the liquid return measurement after absorption of the artificial urine was visually observed from the surface sheet side, and the diffusion area of the artificial urine at the absorbent core part was measured, and the measured value was determined as the absorbent core liquid diffusion area (cm 2 ) It was.
- the artificial urine the same artificial urine used in the above ⁇ Method for measuring liquid permeation time> was used.
- the diaper of each example has less liquid return under no pressure compared to the diaper of each comparative example, and as a result, when the diaper after absorption of artificial urine was touched In addition, stickiness was felt in each of the comparative examples, whereas stickiness was not felt in each of the examples. Moreover, since the diaper of each Example has little intermediate
- the uneven absorbent core (Example 6)
- the amount of liquid return under no pressure is small and the absorption is less than when the flat absorbent core (Example 1) is used. It is clear that the use of the uneven absorbent core is effective in preventing the return of the liquid and the efficient use of the absorbent core because of the large diffusion area of the absorbent core liquid.
- the diaper of each comparative example is mainly due to the fact that the third liquid permeation time of the core wrap sheet exceeds 60 seconds, and the liquid permeation time is 60 seconds or less. Compared to diapers, at least the liquid return amount under no pressure was large, and the absorbent core liquid diffusion area was small.
- the core wrap sheet D used in each comparative example has a hydrophilicity imparted by attaching a hydrophilic agent to the surface of the constituent fibers of the originally water-repellent nonwoven fabric.
- the wrap sheet has a reduced hydrophilicity (improves water repellency) due to repeated discharge and absorption of body fluids such as urine during use of the absorbent article, resulting in a decrease in liquid permeability. To do.
- the diaper of Comparative Example 2 is compared with each Example and Comparative Example 1 in which the constituent fiber of the intermediate layer is 100% of the crosslinked cellulose fiber because the constituent fiber of the intermediate layer is 100% of the pulp fiber.
- the liquid return amount and the intermediate layer liquid remaining amount were considerably large.
- the intermediate layer includes cross-linked cellulose fibers
- the liquid permeation time from the first to the third time is all 60 seconds or less when the core permeation sheet is measured by repeating the liquid permeation time three times or more by a predetermined measurement method. It is.
- paper containing hydrophilic fibers such as pulp (the specific paper) and a synthetic resin preliminarily kneaded with a hydrophilizing agent are used as fiber raw materials. It is clear that a nonwoven fabric containing the agent-kneaded synthetic fiber (the specific hydrophilic nonwoven fabric) is suitable.
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Abstract
Description
<液透過時間の測定方法>
上下端が開口している内径35mmの2本の円筒を、両円筒の軸を一致させて上下に配し、70mm四方の測定対象シート(コアラップシート)の上側に直径55mmの円形状のろ紙1枚を重ね合わせたものを、上下の円筒間に挟み込み、その状態で、上側の円筒内に人工尿を40g供給する。供給された人工尿は、ろ紙及び測定対象シートを順次透過し、下側の円筒内を通って該円筒の下端から流れ落ちる。この下側の円筒から流れ落ちる人工尿の重量の経時変化を観察し、人工尿の供給開始時から該重量が20gになるまでの時間を測定し、その時間を液透過時間とする。
図3に示すように、上下端が開口している内径35mmの2本の円筒91,92を、両円筒91,92の軸を一致させて上下に配し、70mm四方の測定対象シートS(コアラップシート)の上側に直径55mmの円形状のろ紙1枚(図3中符号S1で示す)を重ね合わせたものを、上下の円筒91,92間に挟み込む。このとき、上側の円筒91の下端及び下側の円筒92の上端に設けられた環状のフランジ部にクリップ93を嵌合させ、上下の円筒91,92を連結させることが好ましい。符号94は、円筒91,92の内径と同径同形状の貫通孔を有するゴム製等のパッキンである。尚、測定で使用するろ紙は、ろ紙規格の保留粒子径が1~7μmのろ紙であり、市販品では、アドバンテック社製の型番No.1,4,6,7から適宜選択して使用できる。このように、上下の円筒91,92でろ紙S1及び測定対象シートSを挟持固定した状態で、上側の円筒91内に、図3中符合Wで示す人工尿を、40gの人工尿が入った容器(図示せず)から該人工尿を一括で一気に上側の円筒91内に注入することによって供給する。供給された人工尿は、ろ紙S1及び測定対象シートSを順次透過し、下側の円筒92内を通って該円筒92の下端から流れ落ちる。この下側の円筒92から流れ落ちる人工尿の重量の経時変化を、電子天秤等の重量測定手段を用いて観察し、人工尿の供給開始時から該質量が20gになるまでの時間を測定し、その時間を液透過時間とする。複数回の測定においては、1回の測定終了の度に、測定対象シートSの水分(人工尿)を吸水シート等で吸水する等して除去する。
特定紙は、フリーネスが400~550mlである針葉樹晒クラフトパルプを主体とし、2種以上の紙力増強剤が添加されており、坪量が10~14.5g/m2、密度が0.05~0.2g/cm3、クレープ率が5~30%である。以下、この特定吸収紙について説明する。
繊維粗度計FS-200(KAJAANI ELECTRONICS LTD.製)を用いて測定する。測定対象の繊維(パルプ)は未叩解のものとする。先ず、測定対象の繊維の真の重量を求めるために、該繊維を真空乾燥機内にて100℃で1時間乾燥させ、繊維中に存在している水分を除去する。こうして乾燥させた繊維から1gを正確に量りとる(誤差±0.1mg)。次に、量り取った繊維を、該繊維に極力損傷を与えないように注意しつつ、前記繊維粗度計に付属のミキサーで150mlの水中に完全に離解させ、これを全量が5000mlになるまで水で薄めて希釈液を得た。得られた希釈液から50mlを正確に量りとってこれを繊維粗度測定溶液とし、前記繊維粗度計の操作手順に従って目的とする繊維粗度及び平均繊維長をそれぞれ算出する。尚、平均繊維長の算出には、前記操作手順に基づき下記式により計算された値を用いる。
V={T×B×B×(100+A)/100}
測定対象シート(特定紙)から長さ方向(特定紙の製造時の搬送方向、MD)に200mm、幅方向(MDに直交する方向、CD)に100mmの矩形形状を切り出してサンプルとする。この矩形形状のサンプルを10分間水中に浸漬した直後のMDの長さCを測定し、次式によりクレープ率を算出する。 クレープ率(%)={(C-200)/200}×100
例えば、10分間浸漬後のMDの長さCが220mmであった場合、前記式により算出される当該特定紙のクレープ率は10%である。
特定親水性不織布は、予め親水化剤が練り込まれた合成樹脂を繊維原料とする、親水化剤練り込み型合成繊維を含んでいる。即ち、親水化剤練り込み型合成繊維は、予め親水化剤が練り込まれた合成樹脂を繊維に成形する工程を経て得られるものであり、「合成樹脂からなる繊維に、親水化剤の溶液を噴霧・塗工する等して、該繊維の表面に親水化剤を付着させて得られたもの」とは異なる。親水化剤練り込み型合成繊維は、尿等の体液を繰り返し浴びても親水化剤が外部に流出し難く、親水性が低下し難いという特長を有している。
測定対象シート(コアラップシート)から吸収性物品の長手方向(測定対象シートの製造時の搬送方向、MD)に200mm、該吸収性物品の幅方向(MDに直交する方向、CD)に50mmの矩形形状の測定片を切り出し、該測定片を、水を張ったバットの該水中に浸して充分に水分を含ませた後、ペーパータオル等の吸水材で該測定片を軽く挟んで余剰の水分を除去し、測定サンプルを調製した。この測定サンプルを、その長手方向(MD)が引張方向となるように、引張試験機(例えば、オリエンテック社製テンシロン引張試験機「RTA-100」)のチャックにチャック間距離150mmで取り付ける。そして、測定サンプルを引張速度300mm/分で引っ張り、該測定サンプルが破断するまでの最大荷重点(破断強度)を、該測定サンプルの湿潤強度とする。
凸部21の高さL1(図5参照)は、好ましくは0.5mm以上、更に好ましくは1mm以上、そして、好ましくは6mm以下、更に好ましくは5mm以下、より具体的には、好ましくは0.5~6mm、更に好ましくは1~5mmである。
凸部21の最大径L2(図5参照)は、好ましくは1mm以上、更に好ましくは0.5mm以上、そして、好ましくは10mm以下、更に好ましくは5mm以下、より具体的には、好ましくは1~10mm、更に好ましくは0.5~5mmである。
吸収性コア40Aの高坪量部41の坪量S41と低坪量部42の坪量S42との比(S42/S41)は、好ましくは20%以上、更に好ましくは30%以上、そして、好ましくは80%以下、更に好ましくは70%以下、より具体的には、好ましくは20~80%、更に好ましくは30%~70%である。
高坪量部41の坪量S41は、好ましくは300g/m2以上、更に好ましくは350g/m2以上、そして、好ましくは900g/m2以下、更に好ましくは800g/m2以下、より具体的には、好ましくは300~900g/m2、更に好ましくは350~800g/m2である。
低坪量部42の坪量S42は、好ましくは100g/m2以上、更に好ましくは150g/m2以上、そして、好ましくは500g/m2以下、更に好ましくは400g/m2以下、より具体的には、好ましくは100~500g/m2、更に好ましくは150~400g/m2である。
高坪量部41の厚みT41は、好ましくは2mm以上、更に好ましくは3mm以上、そして、好ましくは8mm以下、更に好ましくは7mm以下、より具体的には、好ましくは2~8mm、更に好ましくは3~7mmである。
低坪量部42の厚みT42は、好ましくは1.5mm以上、更に好ましくは2.5mm以上、そして、好ましくは4.5mm以下、更に好ましくは4mm以下、より具体的には、好ましくは1.5~4.5mm、更に好ましくは2.5~4mmである。
吸収性コア40Aにおける高坪量部41の面積と、低坪量部42の面積との比率を調整すること具体的には、高坪量部41の面積と低坪量部42の面積との比率を6:4~9:1とすることが好ましく、7:3~8:2とすることが更に好ましい。
前記中間層は、架橋セルロース繊維を含んで構成されており、
前記吸収体は、吸収性材料を含有する吸収性コアと、該吸収性コアの少なくとも肌対向面を被覆し、紙又は親水性不織布を含むコアラップシートとを含んで構成されており、
前記コアラップシートについて、下記測定方法により液透過時間を3回以上繰り返して測定した場合に、1回目から3回目までの液透過時間が全て60秒以下である吸収性物品。
<液透過時間の測定方法>
上下端が開口している内径35mmの2本の円筒を、両円筒の軸を一致させて上下に配し、70mm四方の測定対象シート(コアラップシート)の上側に直径55mmの円形状のろ紙1枚を重ね合わせたものを、上下の円筒間に挟み込み、その状態で、上側の円筒内に人工尿を40g供給する。供給された人工尿は、ろ紙及び測定対象シートを順次透過し、下側の円筒内を通って該円筒の下端から流れ落ちる。この下側の円筒から流れ落ちる人工尿の重量の経時変化を観察し、人工尿の供給開始時から該重量が20gになるまでの時間を測定し、その時間を液透過時間とする。
<3> 前記コアラップシートは、前記吸収性コアの幅方向の長さの2倍以上3倍以下の幅を有しており、1枚の該コアラップシートによって、該吸収性コアの肌対向面及びその反対側の非肌対向面それぞれの全域が被覆されている前記<1>又は<2>記載の吸収性物品。
<5> 前記特定紙は、フリーネスが400~550mlである針葉樹晒クラフトパルプ(NBKP)を必須成分として含有している前記<4>記載の吸収性物品。
<6> 前記特定紙に用いるNBKPの繊維粗度は、0.1mg/m以上、更に好ましくは0.12mg/m以上、そして、0.2mg/m以下、好ましくは0.18mg/m以下である前記<4>又は<5>記載の吸収性物品。
<7> 前記特定紙に用いるNBKPの平均繊維長は、1mm以上、好ましくは2mm以上、そして、4mm以下、好ましくは3mm以下である前記<4>~<6>の何れか一項に記載の吸収性物品。
<8> 前記特定紙に添加される紙力増強剤は、カルボキシメチルセルロース(CMC)及びその塩、ポリアクリルアミド系樹脂及びその塩、カチオン化デンプン並びにポリビニルアルコール(PVA)からなる群から選択される1種以上である前記<4>~<7>の何れか一項に記載の吸収性物品。
<9> 前記特定紙に添加される紙力増強剤の組み合わせは、2種の乾燥紙力増強剤及び1種の湿潤紙力増強剤である前記<8>記載の吸収性物品。
<10> 前記特定紙における2種以上の紙力増強剤の総添加量は、特定紙の全構成繊維の乾燥質量に対して、0.01質量%以上、好ましくは0.03質量%以上、そして、1.5質量%以下、好ましくは1.2質量%以下である前記<4>~<9>の何れか一項に記載の吸収性物品。
<11> 前記特定紙の坪量は、10g/m2以上、好ましくは11g/m2以上、そして、14.5g/m2以下である前記<4>~<10>の何れか一項に記載の吸収性物品。
<12> 前記特定紙の密度は、0.05g/cm3以上、好ましくは0.1g/cm3以上、そして、0.2g/cm3以下である前記<4>~<11>の何れか一項に記載の吸収性物品。
<13> 前記特定紙は、クレープ(ちりめん状のシワ)を有しており、そのクレープ率が5~30%である前記<4>~<12>の何れか一項に記載の吸収性物品。
<15> 前記SMS不織布の坪量は、5g/m2以上、好ましくは8g/m2以上、そして、30g/m2以下、好ましくは20g/m2以下である前記<14>記載の吸収性物品。
<17> 前記吸収性コアは、吸収性材料として、木材パルプである天然セルロース繊維及び/又は親水性合成繊維(以上、繊維材料)と吸水性ポリマーとを含有している前記<1>~<16>の何れか一項に記載の吸収性物品。
<18> 前記高坪量部と前記低坪量部とは、前記吸収性コアの長手方向及び幅方向それぞれに交互に形成されており、
より具体的には、前記吸収性コアには、該吸収性コアの長手方向に沿ってその全長に亘って延びる直線状の低坪量部と、該吸収性コアの幅方向に沿ってその全長に亘って延びる直線状の低坪量部とがそれぞれ複数形成され、低坪量部全体として格子状に形成されている前記<16>又は<17>記載の吸収性物品。
<19> 前記吸収性コアの断面視において、前記低坪量部は、前記吸収性コアの厚み方向に偏在しており、
より具体的には、前記低坪量部は、前記吸収性コアの厚み方向において肌対向面側に偏在し、該肌対向面は、実質的に凹凸が無く平坦で、該吸収性コアの非肌対向面は、突出形成された前記高坪量部(凸部)と2つの該高坪量部間に位置する該低坪量部(非凸部あるいは凹部)とによる凹凸を有している前記<16>~<18>の何れか一項に記載の吸収性物品。
<20> 前記吸収性コアの前記高坪量部の坪量(S41)と前記低坪量部の坪量(S42)との比(S42/S41)は、20%以上、好ましくは30%以上、そして、80%以下、好ましくは70%以下である前記<16>~<19>の何れか一項に記載の吸収性物品。
<21> 前記高坪量部の坪量は、300g/m2以上、好ましくは350g/m2以上、そして、900g/m2以下、好ましくは800g/m2以下である前記<16>~<20>何れか一項に記載の吸収性物品。
<23> 前記中間層は、セルロース分子内又は分子間を架橋剤で架橋させてなる架橋セルロース繊維を含んで構成されている前記<1>~<22>の何れか一項に記載の吸収性物品。
<24> 前記架橋セルロース繊維は、セルロース繊維の分子内及び分子間の双方が架橋されている前記<23>記載の吸収性物品。
<25> 前記架橋セルロース繊維は、真円度0.5以上のマーセル化パルプを更に架橋させたマーセル化架橋パルプである前記<23>又は<24>記載の吸収性物品。
<26> 前記中間層における繊維材料(前記架橋セルロース繊維を含む全ての繊維材料)の坪量は、前記吸収性コアにおける繊維材料の坪量の0.5~3倍であり、好ましくは1.0~2.5倍である前記<22>~<25>の何れか一項に記載の吸収性物品。
<27> 前記中間層における繊維材料(前記架橋セルロース繊維を含む全ての繊維材料)の坪量は、50g/m2以上、好ましくは100g/m2以上、そして、300g/m2以下、好ましくは250g/m2以下である前記<22>~<26>の何れか一項に記載の吸収性物品。
<28> 前記中間層は、前記吸収体の肌対向面(前記表面シート側の面)の20~80%、好ましくは30~60%を被覆している前記<1>~<27>の何れか一項に記載の吸収性物品。
<30> 前記液透過誠サブレイヤーシートは、紙又は不織布からなる1枚のシートであり、前記中間層の略全域を被覆するように配されている前記<29>記載の吸収性物品。
<31> 前記液透過性サブレイヤーシートは、湿式抄紙により得られた紙、カード法により製造された不織布、エアスルー不織布、レジンボンド不織布、スパンボンド不織布、メルトブローン不織布、スパンレース不織布及びニードルパンチ不織布からなる群から選択される前記<30>記載の吸収性物品。
<32> 前記液透過性サブレイヤーシートの坪量は、20g/m2以上、好ましくは30g/m2以上、そして、70g/m2以下、好ましくは50g/m2以下である前記<29>~<31>の何れか一項に記載の吸収性物品。
<34> 前記表面シートにワセリンが付着されている前記<1>~<33>の何れか一項に記載の吸収性物品。
<35> 前記表面シートにおける前記ワセリンの付着量は、固形分換算で、5g/m2以上、好ましくは10g/m2以上、そして、30g/m2以下、好ましくは20g/m2以下である前記<34>記載の吸収性物品。
<36> 前記裏面シートは、透湿性を有しない樹脂フィルム、微細孔を有し透湿性を有する樹脂フィルム、撥水不織布、又はこれらと他のシートとのラミネート体である前記<1>~<35>の何れか一項に記載の吸収性物品。
<38> 前記展開型の使い捨ておむつの長手方向に沿う両側部それぞれに、一側縁部に弾性部材が伸長状態で固定されているサイドシートが配されており、更に、一対の立体ギャザー及び一対のレッグギャザーが形成されている前記<37>記載の吸収性物品。
NBKP〔商品名「Cariboo」(北米産、Cariboo Pulp and Paper Company製)及び商品名「ARAUCO」(南米産、ARAUCO製)の2種類のパルプ(NBKP)を、両パルプの含有質量比が5/5になるように混合して調製したNBKP〕を水中に均一に分散させて、繊維濃度2質量%のスラリーを調製し、このスラリーを叩解機にかけて、NBKPのフリーネスを500mlに調整した。更に、このスラリーを希釈しながら、湿潤紙力増強剤としてPAE(星光PMC株式会社製、商品名「WS4030」)を、スラリー中の全繊維の乾燥質量に対して0.78質量%投入し、次いで、乾燥紙力増強剤としてCMCのナトリウム塩(第一工業製薬株式会社製、商品名「セロゲンWS-C」)を、スラリー中の全繊維の乾燥質量に対して0.2質量%投入し、各成分が均一になるように十分に撹拌し、固形分濃度0.1質量%のスラリーに調整した。こうして得られたスラリーを、ワイヤー目開き径90μm(166メッシュ)の金網抄紙ワイヤー上に散布し、金網抄紙ワイヤー上に紙層を形成させ、サクションボックスを用いて6ml/(cm2・sec)の速度で該紙層を脱水した後、該紙層をドライヤで乾燥させ、乾燥面からドクターブレードで紙層をはがしながら、ドライヤと巻き取りの速比をつけてクレープを付与した。こうして得られた薄葉紙(クレープ紙)をコアラップシートA-1として用いた。
以下の手順で前記特定紙を製造し、これをコアラップシートA-2とした。NBKP(Cariboo Pulp and Paper Company製、商品名「Cariboo」、北米産、繊維粗度0.15mg/m、平均繊維長2.44mm)を水中に均一に分散させて、繊維濃度2質量%のスラリーを調製し、このスラリーを叩解機にかけて、NBKPのフリーネスを500mlに調整した。更に、このスラリーを希釈しながら、湿潤紙力増強剤としてPAE(星光PMC株式会社製、商品名「WS4030」)を、スラリー中の全繊維の乾燥質量に対して0.78質量%投入し、次いで、乾燥紙力増強剤としてCMCのナトリウム塩(第一工業製薬株式会社製、商品名「セロゲンWS-C」)を、スラリー中の全繊維の乾燥質量に対して0.2質量%投入し、各成分が均一になるように十分に撹拌し、固形分濃度0.1質量%のスラリーに調整した。こうして得られたスラリーを、ワイヤー目開き径90μm(166メッシュ)の金網抄紙ワイヤー上に散布し、金網抄紙ワイヤー上に紙層を形成させ、サクションボックスを用いて6ml/(cm2・sec)の速度で該紙層を脱水した後、該紙層をドライヤで乾燥させ、乾燥面からドクターブレードで紙層をはがしながら、ドライヤと巻き取りの速比をつけてクレープを付与した。こうして得られた坪量13.5g/m2の前記特定紙を、コアラップシートA-2とした。
坪量13g/m2のSMS不織布をコアラップシートBとした。このSMS不織布(コアラップシートB)は、前記形態Aに相当し、該SMS不織布の両面を形成するスパンボンド不織布が、何れも親水化剤練り込み型合成繊維を含む前記特定親水性不織布であった。
坪量13g/m2のSMS不織布をコアラップシートCとした。このSMS不織布(コアラップシートC)は、前記形態Bに相当し、該SMS不織布の一方の面を形成するスパンボンド不織布のみが、親水化剤練り込み型合成繊維を含む前記特定親水性不織布であった。尚、コアラップシートCについては、その使用形態に応じて更に区別し、具体的には、親水化剤練り込み型合成繊維を含む面(前記特定親水性不織布)を肌対向面(上側)にして用いたものをコアラップシートC-1とし、親水化剤練り込み型合成繊維を含む面(前記特定親水性不織布)を非肌対向面(下側)として用いたものをコアラップシートC-2とした。
市販の使い捨ておむつ使用相当の坪量10g/m2のSMS不織布の構成繊維の表面に親水化剤を付着して親水性を付与したものを、コアラップシートDとした。
図1及び図2に示すおむつ1と同様の基本構成を有する展開型の使い捨ておむつ(Mサイズ相当品)を作製し、これを実施例1のサンプルとした。表面シート、液透過性サブレイヤーシート及び中間層としては、それぞれ、市販の使い捨ておむつ(P&G社製、商品名「パンパース コットンケアテープ」)として用いられているシートを用いた。中間層としては、中間層の全構成繊維に占める架橋セルロース繊維の割合は100質量%であった。また、この中間層における繊維材料の坪量は、坪量約180g/m2で、下記吸収性コアにおける繊維材料の坪量の0.9倍であった。裏面シートとしては、坪量25g/m2の液難透過性且つ透湿性のポリエチレン製樹脂フィルム(炭酸カルシウム配合)を用いた。吸収性コアとしては、実質的に凹凸を有していない平坦型吸収性コアとして、繊維集合体に粒子状の吸水性ポリマー(SAP)を保持させたもので、フラッフパルプ200g/m2と吸水性ポリマー286g/m2との均一混合物からなる総坪量486g/m2の吸収性コアを用いた。この吸収性コアの長手方向の全長は370mm、幅方向の全長(最大長さ)は120mmで、該吸収性コアの平面視形状は、図1に示す如き砂時計形状であった。コアラップシートとしては、前記コアラップシートA-1を用いた。
前記コアラップシートA-1に代えて前記コアラップシートA-2を用いた以外は実施例1と同様にして展開型の使い捨ておむつを作製し、実施例2のサンプルとした。
前記コアラップシートA-1に代えて前記コアラップシートBを用いた以外は実施例1と同様にして展開型の使い捨ておむつを作製し、実施例3のサンプルとした。
前記コアラップシートA-1に代えて前記コアラップシートC-1を用いた以外は実施例1と同様にして展開型の使い捨ておむつを作製し、実施例4のサンプルとした。即ち、実施例4では、前記コアラップシートCを、特定親水性不織布である一方のスパンボンド不織布が該コアラップシートCの肌対向面(中間層との対向面)を形成するように、おむつに配置した。
前記コアラップシートA-1に代えて前記コアラップシートC-2を用いた以外は実施例1と同様にして展開型の使い捨ておむつを作製し、実施例5のサンプルとした。即ち、実施例5では、前記コアラップシートCを、特定親水性不織布である一方のスパンボンド不織布が該コアラップシートCの非肌対向面(中間層との非対向面)を形成するように、おむつに配置した。
吸収性コアとして、図6に示す吸収性コア40Aと概ね同様の構成の凹凸型吸収性コアを用いた以外は実施例1と同様にして展開型の使い捨ておむつを作製し、実施例6のサンプルとした。実施例6で用いた凹凸型吸収性コアは、繊維集合体に粒子状の吸水性ポリマーを保持させたもので、長手方向の全長は370mm、幅方向の全長(最大長さ)は120mmであり、平面視形状は砂時計形状であった。凹凸型の高坪量部のブロックの大きさは、10×20mmであり、低坪量部の溝の幅は2mmで形成した。また、実施例6で用いた凹凸型吸収性コアは、フラッフパルプ平均223g/m2と吸水性ポリマー平均243g/m2との均一混合物からなる総坪量平均466g/m2と、低坪量部がフラッフパルプ平均152g/m2と吸水性ポリマー平均105g/m2との均一混合物からなる総坪量平均257g/m2であり、高坪量部と低坪量部とのフラッフパルプの坪量比(高坪量部/低坪量部)が1.5、吸収性ポリマーの坪量比(高坪量部/低坪量部)が2.3である。
前記コアラップシートAに代えて前記コアラップシートDを用いた以外は実施例1と同様にして展開型の使い捨ておむつを作製し、比較例1のサンプルとした。
中間層として坪量180g/m2のフラッフパルプを用いた以外は比較例1と同様にして展開型の使い捨ておむつを作製し、比較例2のサンプルとした。比較例2で用いた中間層(パルプ)は、架橋セルロース繊維を含んでおらず、パルプ繊維(NBKP100%)を構成繊維とする。
実施例及び比較例の各サンプル(使い捨ておむつ)について、一定加圧下における液吸収時間、並びに無加圧下における液戻り量及び中間層液残り量及び吸収性コア液拡散面積を、それぞれ下記測定方法によって測定した。また、各サンプルにおけるコアラップシートについて、前記測定方法により湿潤強度を測定した。その結果を下記表2に示す。
使い捨ておむつを平面状に拡げ、表面シートを上に向けて水平面上に固定した無加圧の状態で、吸収体の中心部における該表面シート上に人工尿40gを注入速度5g/秒で注入して吸収させ、10分間放置し、更に人工尿40gを同じ注入速度で注入して吸収させた。斯かる人工尿の注入操作を3回繰り返し、合計120gの人工尿をおむつに吸収させた。次いで、おむつにおける人工尿の吸収部位上に、一辺が70mmの正方形形状のコラーゲンフィルム(Naturin社製、商品名「COFFI」)を4枚重ね、更にその上に荷重を1分間加えて、おむつに吸収させた人工尿をコラーゲンフィルムに吸収させた。このコラーゲンフィルムは、接触角が人肌と略同じである。荷重は、円状凸部(直径20mm、高さ5mm)を中央部に配する70mm×70mmの正方形形状のアクリルプレートに4kg(液注入後の湿潤時おむつ上に、約7kPa:最小2kPa~最大21kPa)が加わるようにした。1分間経過後荷重を取り除き、人工尿を吸収したコラーゲンフィルムの重量(g)を測定した。この重量から人工尿吸収前のコラーゲンフィルムの重量を差し引き、その値を無加圧下における液戻り量(g)とした。また、人工尿吸収後の液戻り量測定後のおむつから中間層及び液透過性サブレイヤーシートを取り出して重量(g)を測定し、その測定値に前記「無加圧下における液戻り量(g)」を足し合わせ、その値を中間層液残り量とした。無加圧下における液戻り量及び中間層液残り量が少ないほど、高評価となる。また、人工尿吸収後の液戻り量測定後のおむつを表面シート側から目視し、吸収性コア部位の人工尿の拡散面積を測定し、その測定値を吸収性コア液拡散面積(cm2)とした。吸収性コア液拡散面積が大きいほど、液拡散性に優れると判断され、高評価となる。尚、人工尿としては、前記<液透過時間の測定方法>で用いた人工尿と同じものを用いた。
Claims (7)
- 肌対向面側に液透過性の表面シート、非肌対向面側に液難透過性の裏面シート、及び両シート間に配された吸収体を備え、該表面シートと該吸収体との間に中間層が配されている吸収性物品であって、
前記中間層は、架橋セルロース繊維を含んで構成されており、
前記吸収体は、吸収性材料を含有する吸収性コアと、該吸収性コアの少なくとも肌対向面を被覆し、紙又は親水性不織布を含むコアラップシートとを含んで構成されており、
前記コアラップシートについて、下記測定方法により液透過時間を3回以上繰り返して測定した場合に、1回目から3回目までの液透過時間が全て60秒以下である吸収性物品。
<液透過時間の測定方法>
上下端が開口している内径35mmの2本の円筒を、両円筒の軸を一致させて上下に配し、70mm四方の測定対象シート(コアラップシート)の上側に直径55mmの円形状のろ紙1枚を重ね合わせたものを、上下の円筒間に挟み込み、その状態で、上側の円筒内に人工尿を40g供給する。供給された人工尿は、ろ紙及び測定対象シートを順次透過し、下側の円筒内を通って該円筒の下端から流れ落ちる。この下側の円筒から流れ落ちる人工尿の重量の経時変化を観察し、人工尿の供給開始時から該重量が20gになるまでの時間を測定し、その時間を液透過時間とする。 - 前記コアラップシートは、スパンボンド-メルトブローン-スパンボンド不織布からなり、且つ該不織布の少なくとも一方の面を形成するスパンボンド不織布が、予め親水化剤が練り込まれた合成樹脂を繊維原料とする、親水化剤練り込み型合成繊維を含んでいる請求項1記載の吸収性物品。
- 前記吸収性コアは、前記吸収性材料が相対的に多い高坪量部と、前記吸収性材料が相対的に少ない低坪量部とを有し、該高坪量部と該低坪量部とが、所定方向に交互に形成されている請求項1又は2記載の吸収性物品。
- 前記中間層における繊維材料の坪量は、前記吸収性コアにおける繊維材料の坪量の
0.5~3倍である請求項1~3の何れか一項に記載の吸収性物品。 - 前記表面シートと前記中間層との間に液透過性サブレイヤーシートが配されている請求項1~4の何れか一項に記載の吸収性物品。
- 前記表面シートは、着用者の肌側に向けて突出する凸部と該凸部に隣接する凹部とをそれぞれ多数有している請求項1~5の何れか一項に記載の吸収性物品。
- 前記表面シートにワセリンが付着されている請求項1~6の何れか一項に記載の吸収性物品。
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JP5800959B1 (ja) * | 2014-06-23 | 2015-10-28 | ユニ・チャーム株式会社 | 使い捨ておむつ |
JP6285812B2 (ja) * | 2014-06-30 | 2018-02-28 | ユニ・チャーム株式会社 | 使い捨ておむつ |
JP6647015B2 (ja) * | 2014-12-16 | 2020-02-14 | 花王株式会社 | 吸収性物品 |
WO2016098532A1 (ja) * | 2014-12-16 | 2016-06-23 | 花王株式会社 | 吸収性物品 |
JP6185033B2 (ja) * | 2015-09-30 | 2017-08-23 | ユニ・チャーム株式会社 | 吸収性物品用の吸収体 |
US20170203542A1 (en) * | 2016-01-15 | 2017-07-20 | First Quality Nonwovens, Inc. | Nonwoven composite including natural fiber web layer and method of forming the same |
JP6626375B2 (ja) * | 2016-03-07 | 2019-12-25 | 花王株式会社 | クレープ紙及びその製造方法、並びに吸収性物品の製造方法 |
WO2018148640A1 (en) | 2017-02-13 | 2018-08-16 | The Procter & Gamble Company | Methods of making three-dimensional laminates for absorbent articles |
WO2018204613A1 (en) | 2017-05-03 | 2018-11-08 | The Procter & Gamble Company | Absorbent article having multiple zones |
EP3706697B1 (en) | 2017-11-06 | 2023-11-08 | The Procter & Gamble Company | Structure having nodes and struts |
US10918532B2 (en) | 2017-12-19 | 2021-02-16 | The Procter & Gamble Company | Methods of making elastic belts for absorbent articles |
JP7126430B2 (ja) * | 2018-11-27 | 2022-08-26 | 花王株式会社 | 吸収性物品 |
JP6824948B2 (ja) * | 2018-12-13 | 2021-02-03 | 花王株式会社 | 吸収体及び吸収性物品 |
WO2020167171A1 (en) * | 2019-02-15 | 2020-08-20 | Essity Hygiene And Health Aktiebolag | Absorbent article |
WO2021112212A1 (ja) * | 2019-12-04 | 2021-06-10 | 東レ株式会社 | 吸収体および衛生材料製品 |
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RU159420U1 (ru) | 2016-02-10 |
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