TW202009018A - Absorbent article - Google Patents

Abstract

To provide an absorbent article which reduces the burden on a wearer's skin. This absorbent article has a top sheet 30 provided on the skin side and an absorbent body 56 provided on the back side of the top sheet 30, wherein the top sheet 30 is configured from multiple layers, of which the layer positioned on the skin side does not contain acids and the layer positioned on the back side contains acids.

Description

Absorbent article

The present invention relates to an absorbent article whose top sheet is composed of a plurality of layers. Among the plurality of layers, the layer on the skin side does not contain acid, and the layer on the back side contains acid.

The excrement or urine excreted by the wearer of the absorbent article is absorbed by the absorbent article. The pH of the part that has absorbed fecal water or urine changes according to the elapsed time after excretion. For example, in the case of urinary excretion, the pH of the absorption site immediately after excretion is often 6.5. Over time, urea in the urine is broken down by hydrolytic enzymes (such as urease) to produce Armonia. As a result, the pH of the absorption site tends to be on the alkaline side, and may sometimes become about pH 11.

Prolonged contact between the wearer's skin and the alkaline absorption site will cause a burden on the skin. In particular, compared with adults, the skin layer of children who are born shortly (children at the age of low months) is thin and easily burdens the skin.

There is a prior art (Patent Documents 1 to 3 below) which mixes an acidic component in a sheet on the skin side of an absorbent article to prevent the excrement from becoming alkaline due to armonia generated after urination side.

In the absorbent article of Patent Document 1, a convex portion is provided on the front sheet, the weak acidulant is contained in the top and the side wall portion of the convex portion, and the fiber density of the side wall portion is smaller than the fiber density of the top portion. According to this absorbent article, in the case where the weak acidulant contained in the top portion and the side wall portion is eluted into the excretion liquid, a certain amount of discharge liquid also remains as a residual liquid in the side wall portion with a low fiber density, so The pH of the convex portion can be maintained at a weak acidity.

The absorbent article of Patent Document 2 includes a sheet containing fumaric acid, which contains fumaric acid in a sheet base material using paper as a main material; and, fumaric acid in the aforementioned sheet containing fumaric acid The content rate is 0.00015 mass% to 1.5 mass%. According to this absorbent article, it is possible to prevent the wearer's skin from being inflamed, and to suppress the propagation of bacteria after excretion, thereby suppressing the occurrence of malodor, and as a result, it is possible to maintain antibacterial and deodorize and eliminate fruit for a long time.

The absorbent article of Patent Document 3 uses weak acid pulp as the raw material of the absorber, mixes the antibacterial high-absorbent polymer in the absorber, disperses the citric acid composed of granular bodies in the absorber, and absorbs A liquid-permeable sheet impregnated with malic acid is arranged above the body. Based on this absorbent article, the combination of "weak acid pulp", "antibacterial superabsorbent polymer", "citric acid", and "malic acid" can dramatically improve the combination of individual or partial Deodorant effect when worn for a long time that is not available in the medium.

[Prior Technical Literature] (Patent Literature) Patent Document 1: Japanese Patent No. 6033981 Patent Document 2: Japanese Patent Application Publication No. 2017-184962 Patent Document 3: Japanese Patent Application Publication No. 2014-079284

[Problems to be solved by the invention] If the acidic component is blended in the sheet on the skin side of the absorbent article, the following problems (A) to (C) will occur. (A) If the acid component that has been formulated in the sheet is lost due to excretion, the effect of alkalinization suppression by the acid component cannot be expected when it is excreted repeatedly. (B) In a state where the wearer of the absorbent article is not excreted, a sheet containing an acidic component (for example, at a pH of about 3) continuously contacts the wearer's skin, which causes a burden on the skin. (C) Among absorbent articles, unreacted acidic components may be re-infiltrated together with excrement and come into contact with the wearer's skin at the site of body pressure.

Furthermore, the aforementioned patent documents 1 to 3 have the following problems. In the absorbent article described in Patent Document 1, it is necessary to provide a convex portion on the front sheet, and the placement position of the weak acidulant is also limited. Therefore, there is a problem that the structure of the absorbent article is limited and the manufacturing method is not easy to simplify.

The absorbent article described in Patent Document 2 uses a sheet impregnated with fumaric acid, but fumaric acid is not easily dissolved in water, so it is difficult to apply fumaric acid and a hydrophilic agent to fibers together, and There are problems that are not easy to manufacture.

The absorbent article described in Patent Document 3 uses a top sheet impregnated with malic acid, but malic acid tends to be relatively irritating to the skin and causes problems.

Therefore, the problem to be solved by the present invention is to provide an absorbent article that can reduce the burden on the wearer's skin.

[Technical means to solve the problem] The various aspects of the adhesive-type disposable diaper that solve the above problems are as follows. >First aspect> An absorbent article having a top sheet provided on the skin side and an absorber provided on the back side of the top sheet. The absorbent article is characterized by: The aforementioned top sheet is composed of a plurality of layers; Among the plurality of layers, the layer on the skin side contains no acid and the layer on the back side contains acid.

(Effect) In the first aspect, the topsheet contains no acid. This top sheet, unlike the middle sheet and the packaging sheet, has the particularity of directly contacting the wearer's skin. Therefore, it is particularly important to prevent the excreta adhering to the top sheet from tending to (becoming) the alkaline side. Thus, the top sheet contains acid, whereby the tendency toward the alkaline side can be prevented, and the burden on the wearer's skin can be reduced. For example, when the wearer urinates, the urea contained in the urine can be decomposed into Armonia by urease, and this Armonia can be neutralized by the acid of the top sheet.

In addition, this top sheet contacts the wearer's skin, so the acid contained in the top sheet may cause a burden on the wearer's skin. Thus, the top sheet is composed of a plurality of layers, and the layer on the skin side is free of acid, thereby preventing the acid from burdening the wearer's skin.

>Second aspect> The absorbent article as described in the first aspect above, wherein the acid contained in the top sheet is a water-soluble acid; The top sheet contains the water-soluble acid and the hydrophilic agent.

(Effect) The acid contained in the top sheet is preferably a water-soluble acid. The poorly soluble acid has low affinity with the hydrophilic agent and is not easily attached to the fibers constituting the top sheet.

When the wearer of the absorbent article of this aspect excretes, the excrement comes into contact with the water-soluble acid contained in the top sheet, thereby suppressing the tendency of the excrement toward the alkaline side.

Moreover, due to the action of the hydrophilic agent contained in the top sheet, water-soluble acids are not easily lost from the top sheet. That is, the water-soluble acid is held in the structure between the fibers constituting the topsheet in the state of being chemically combined with the hydrophilic agent, so even when urinating repeatedly, the water-soluble acid will be rendered water-soluble by the action of the hydrophilic agent Not easy to lose. Such a top sheet can be produced, for example, by coating a fiber constituting the top sheet with a water-soluble acid and a hydrophilic agent.

According to the present embodiment, even after the wearer has excreted a plurality of times, the water-soluble acid remains in the topsheet, so the excrement remaining inside the topsheet can be continuously restrained from being alkaline. Side tendency. In addition, the hydrophilic agent is used to prevent the water-soluble acid from being lost from the top sheet due to excretion. Therefore, the water-soluble acid and the hydrophilic agent are preferably provided at the same position of the top sheet when viewed from above.

In addition, when the topsheet is composed of hydrophobic fibers, the water-repellent effect of the fibers may cause excreta to stay on the skin surface of the topsheet, and there is a problem that the excreta do not easily reach the absorber. As in this aspect, by including a hydrophilic agent in the top sheet, it is possible to prevent the retention of such excreta and allow the excreta to quickly reach the absorbent body.

>Third Aspect> The absorbent article as described in the second aspect above, wherein the hydrophilic agent comprises: polyglycerin fatty acid ester, polyether-polyester block copolymer, polyether modified silicone, or ethylene oxide plus Fatty acid esters into polyols, or a combination of these.

(Effect) The hydrophilic agent contained in the top sheet is preferably a hydrophilic agent having a high effect of preventing the loss of water-soluble acid. As such a highly effective hydrophilic agent, polyglycerin fatty acid ester, polyether-polyester block copolymer, polyether modified silicone, and ethylene oxide addition polyol fatty acid can also be used alone Ester can also use a combination of these. Also, any combination of these substances and other conventional substances may be used.

>Fourth Aspect> The absorbent article as described in the second or third aspect, wherein the topsheet contains the water-soluble acid and the hydrophilic agent, In the artificial urine dropping test, the first measurement result was 10 points, the second measurement result was 10 points, and the third measurement result was 9 points or more.

(Effect) Prepare a top sheet, which is composed of a plurality of layers. Among the plurality of layers, the layer on the skin side does not contain water-soluble acid and the layer on the back side contains water-soluble acid. In the urine drip test, a top sheet of the first measurement result of 10 points, the second measurement result of 10 points, and the third measurement result of 9 points or more may be used for the absorbent article. Even after the wearer has excreted multiple times, the water-soluble acid and hydrophilic agent are not easily lost from the top sheet, so the burden on the wearer's skin can be reduced for a long time. In addition, the conditions such as the number and thickness of the top sheet used in the artificial urine dropping test, the raw material of the fiber of the top sheet, and the manufacturing method are all the same as the top sheet actually installed in the absorbent article.

The dropping test of artificial urine is carried out according to the following procedures (1) to (4). >Drip test of artificial urine> (1) Place the top sheet on top of 10 sheets of filter paper, and place a metal jig with 10 holes on the top sheet. (2) Using a micro-dropper, drop 1 mL of artificial urine into each of the 10 holes of the metal fixture, and after dripping, confirm whether the top sheet has absorbed the artificial urine within 2 seconds. The absorbed holes were counted as 1 point, the non-absorbed holes were counted as 0 points, and the total number of points of 10 holes was recorded as the first measurement result. (3) After 3 minutes have elapsed since the artificial urine was dripped in the above (2), using a micro-dropper, drip 1 mL of artificial urine into each of the 10 holes of the metal fixture, and after dripping, in 2 seconds Confirm whether the topsheet has absorbed the artificial urine, count the absorbed holes as 1 point, calculate the non-absorbed holes as 0 points, and record the total number of 10 holes as the second measurement result. (4) After 6 minutes from the dripping of artificial urine in (3) above, using a glass dropper, drip 500 μL of artificial urine in each of the 10 holes of the metal fixture, and after dripping, in 2 seconds Confirm whether the topsheet has absorbed the artificial urine, count the absorbed holes as 1 point, calculate the non-absorbed holes as 0 points, and record the total number of 10 holes as the third measurement result.

The artificial urine used in the aforementioned artificial urine dropping test is composed of 2wt% urea, 0.8wt% sodium chloride, 0.03wt% calcium chloride dihydrate, 0.08wt% magnesium sulfate heptahydrate, and 97.09wt Artificial urine mixed with% ion-exchanged water.

The metal fixture used in the artificial urine dropping test is a rectangle with a width of 210 mm, a length of 50 mm, and a thickness of 5 mm, and a weight of 400 g; each hole is a circle with a diameter of 15 mm, and in the width direction and In the longitudinal direction, they are spaced at intervals of 4 mm, and are arranged at equal intervals.

>Fifth Aspect> The absorbent article according to any one of the first aspect to the fourth aspect, wherein an intermediate sheet is provided between the top sheet and the absorber; The aforementioned intermediate sheet contains a water-soluble acid and a hydrophilic agent.

(Effect) The intermediate sheet does not directly contact the skin of the wearer, but when the wearer excretes, there is a possibility that excrement remains in the intermediate sheet. Furthermore, if the excrement in this intermediate sheet is alkalized and re-infiltrated to the skin side of the top sheet (the excrement in the intermediate sheet moves toward the skin side of the top sheet), it contacts the wearer’s skin and wears on The skin of the person is burdened. Therefore, by including a water-soluble acid in this intermediate sheet, it is possible to prevent the burden on the wearer's skin.

Also, generally speaking, the middle sheet is mostly bulkier than the top sheet and the packaging sheet. Therefore, compared with the top sheet and the packaging sheet, the amount of excrement remaining in the middle sheet tends to be larger. Therefore, in consideration of the phenomenon of re-infiltration, it is more advantageous to include a water-soluble acid in the intermediate sheet containing more excreta than to include a water-soluble acid in the packaging sheet. In addition, since the intermediate sheet is located on the skin side more than the packaging sheet, from this point of view, it is also known that the intermediate sheet close to the skin side contains a water-soluble acid and is more useful than the packaging sheet.

>Sixth Aspect> The absorbent article according to any one of the first aspect to the fifth aspect, wherein a packaging sheet covering the absorbent body is provided; The aforementioned packaging tablet contains a water-soluble acid and a hydrophilic agent.

(Effect) The packaging sheet does not directly contact the wearer's skin, but when the wearer excretes, there is a possibility that excrement may remain in the packaging sheet. Furthermore, if the excrement in this packaging sheet is alkalized and re-permeated to the skin side of the top sheet (the excrement in the packaging sheet moves toward the skin side of the top sheet), it will contact the wearer’s skin The skin of the person is burdened. Therefore, by including a water-soluble acid in this packaging sheet, it is possible to prevent the burden on the wearer's skin. In addition, in general, there are many opportunities for the packaging sheet to come into contact with the absorbent body that holds the excrement. That is, since the water-soluble acid contained in the packaging sheet acts on the excrement held by the absorber, the effect of suppressing the tendency of the excrement toward the alkaline side is high.

>Seventh Aspect> The absorbent article according to any one of the first aspect to the sixth aspect, wherein the fiber diameter of the top sheet is 4.0 dtex or more.

(Effect) By making the fiber diameter of the top sheet thicker, excreta can be quickly absorbed. Therefore, it is possible to reduce the time that the excrement contacts the wearer's skin. In parallel with this, it is possible to prevent excreta from accumulating on the front of the top sheet and spreading over a wide range, so it is possible to reduce the area where excreta adheres to the wearer's skin. As a result, the burden on the skin caused by the tendency of the excrement toward the alkaline side can be reduced. The fiber diameter of such a top sheet is preferably 4.0 dtex or more, and more preferably 5.0 tex or more.

>Eighth aspect> The absorbent article according to any one of the first aspect to the sixth aspect, wherein among the plurality of layers of the top sheet, the fiber diameter of the layer on the skin side is more than that on the back side The fiber diameter of the layer is smaller.

(Effect) The top sheet is composed of a plurality of layers, and the fiber diameter of the layer on the skin side is reduced, thereby making the skin feel good, so the burden on the skin side of the wearer can be reduced. Also, by increasing the fiber diameter of the layer located on the back side, the same effect as the seventh aspect described above can be obtained.

>Ninth Aspect> The absorbent article according to the eighth aspect, wherein among the plurality of layers of the top sheet, the fiber diameter of the layer on the skin side is 2.5 dtex or less, and the fiber diameter of the layer on the back side is 4.0dtex or more.

(Effect) The top sheet is composed of a plurality of layers, and the fiber diameter of the layer on the skin side is reduced, thereby making the skin feel good, so the burden on the skin side of the wearer can be reduced. In addition, by increasing the fiber diameter of the layer on the back side, the same effects as those described in the seventh aspect can be obtained.

Specifically, the fiber diameter of the layer located on the skin side is preferably 2.5 dtex or less, and more preferably 1.7 dtex or less. In addition, the fiber diameter of the layer located on the back side is preferably 4.0 dtex or more, and more preferably 5.0 dtex or more. By setting the fiber diameter in the above range, the same effect as the aforementioned seventh aspect becomes remarkable.

>Tenth Aspect> The absorbent article according to any one of the first aspect to the ninth aspect, wherein an intermediate sheet is provided between the top sheet and the absorber; The weight per unit area of the intermediate sheet is 20 gsm or more.

(Effect) If the wearer's body pressure is exerted on the absorbent article, a phenomenon in which the excretion held by the absorbent body moves toward the skin side may occur. Therefore, by setting the weight per unit area of the intermediate sheet to be large, it is possible to reduce the amount of excreted excrement. In particular, if a part of the acid contained in the top sheet is lost to be contained in the absorber, and re-infiltration occurs, the acid of the top sheet may adhere to the wearer's skin and burden the wearer's skin. . It is possible to reduce such a burden by setting the weight per unit area of the intermediate sheet to be larger to prevent back-wetting. The weight per unit area of the intermediate sheet is preferably 20 gsm or more, and more preferably 30 gsm or more.

>Eleventh Aspect> The absorbent article according to any one of the first aspect to the tenth aspect, wherein a packaging sheet covering the absorbent body is provided; The weight per unit area of the packaging sheet is 20 gsm or more.

(Effect) In the tenth aspect, setting the weight per unit area of the intermediate sheet to be large can reduce the re-infiltration, and the same effect can be obtained by setting the weight per unit area of the packaging sheet to be large. The weight per unit area of the packaging sheet is preferably 20 gsm or more, and more preferably 30 gsm or more.

>Twelfth Aspect> The absorbent article according to any one of the first aspect to the eleventh aspect, wherein the acid is citric acid.

(Effect) Citric acid can be used as a food additive to a high degree of safety and has a high effect of suppressing alkalization, so it is suitable.

[Effect of invention] According to the present invention, the burden on the wearer's skin can be reduced.

FIGS. 1 to 5 illustrate adhesive-type disposable diapers as absorbent articles. Symbol X in the figure shows the full width of the diaper except the connecting tape, and symbol L shows the full length of the diaper. Although not shown, the top sheet 30, the intermediate sheet 40, the packaging sheet 58, the absorber 56, the liquid-impermeable sheet 11, and the exterior nonwoven fabric 12 are respectively adhered by a hot-melt adhesive . Hot melt adhesives can be applied by slit coating, continuous linear or dot-and-drop bead coating, spiral or Z-shaped spray coating, or pattern coating (hot-melt bonding by relief method) Coating). Alternatively or in combination, it is possible to apply a hot-melt adhesive to the outer peripheral surface of the elastic member on the fixing portion of the elastic member to fix the elastic member to the adjacent member. The hot-melt adhesive is not particularly limited, and for example, EVA-based, adhesive rubber-based (elastic system), olefin-based, polyester, and polyamide-based types can be used. As a joining means for joining the constituent members, a material welding means such as heat sealing and ultrasonic sealing can be used.

This adhesive-type disposable diaper has a ventral portion F that extends to the front side of the center in the front-rear direction LD, and a back portion B that extends to the rear side of the center in the front-rear direction LD. In addition, this adhesive-type disposable diaper includes an absorber 56 built into the range including the crotch portion, a liquid-permeable top sheet 30 covering the front side of the absorber 56, and a backside covering the absorber 56. The liquid-permeable sheet 11 and the non-woven fabric 12 that cover the back side of the liquid-impermeable sheet 11 and constitute the outer surface of the product.

Hereinafter, the raw materials and characteristic parts of each part will be described in order. (Absorber) The absorber 56 is a part that absorbs and retains excretory liquid, and can be formed by an assembly of fibers. As this fiber aggregate, in addition to an aggregate formed by accumulating short fibers such as cotton pulp or synthetic fibers, a tow (fiber bundle) of synthetic fibers such as cellulose acetate may be used as needed. Fibre filament assembly. The weight per unit area of the fiber may be about 100 to 300 g/m ² in the case of accumulating cotton pulp or short fibers, and may be about 30 to 120 g in the case of filament aggregates, for example. /m ² . The fineness (fineness) in the case of synthetic fibers is, for example, 1 to 16 dtex, preferably 1 to 10 dtex, and more preferably 1 to 5 dtex. In the case of a filament assembly, the filament may be a non-crimped fiber, but it is preferably a crimped fiber. The curl degree of the crimped fiber may be, for example, 5 to 75 per 2.54 cm, preferably 10 to 50, and more preferably about 15 to 50. In addition, crimped fibers that are uniformly crimped may be used.

(Highly absorbent polymer particles) Part or all of the absorber 56 may contain superabsorbent polymer particles. The superabsorbent polymer particles include “powder” in addition to “particles”. As the superabsorbent polymer particles, the superabsorbent polymer particles used in such absorbent articles can be used directly. The particle size of the superabsorbent polymer particles is not particularly limited, but it is desirable that the particle size is, for example, a sieve (a vibration sieve of 5 minutes) using a standard sieve of 500 μm (JIS Z 8801-1:2006), When the particles that fell below the sieve in the above screening were screened using a 180 μm standard sieve (JIS Z 8801-1: 2006) (5 minute shaker), the proportion of particles remaining on the 500 μm standard sieve It is 30% by weight or less, and the proportion of particles remaining on a 180-μm standard sieve is 60% by weight or more.

The material of the superabsorbent polymer particles can be used without particular limitation, but a material having a water absorption of 40 g/g or more is preferred. As the superabsorbent polymer particles, there are superabsorbent polymer particles such as starches, celluloses, and synthetic polymers. Saponification of starch-acrylic acid (salt) graft copolymers and starch-acrylonitrile copolymers can be used. Particles, high-absorbent polymer particles such as sodium carboxymethyl cellulose cross-linked products and acrylic acid (salt) polymers. As the shape of the superabsorbent polymer particles, it is preferably in the form of powders or granules generally used, but other shapes may be used.

As the superabsorbent polymer particles, it is preferable to use superabsorbent polymer particles having a water absorption rate of 70 seconds or less, particularly 40 seconds or less. If the water absorption rate is too slow, the so-called re-osmosis in which the liquid supplied into the absorber 56 returns to the outside of the absorber 56 is likely to occur.

In addition, as the superabsorbent polymer particles, it is preferable to use superabsorbent polymer particles having a gel strength of 1,000 Pa or more. With this, even in the case of the bulky absorbent body 56, the sticky feeling after absorption of the liquid can be effectively suppressed.

The weight per unit area of the superabsorbent polymer particles can be appropriately set according to the amount of absorption required according to the application of the absorbent body 56. Therefore, it cannot be generalized, but it can be 50 to 350 g/m ² . If the weight per unit area of the polymer is less than 50 g/m ² , it is not easy to ensure the absorption capacity. If the weight per unit area of the polymer exceeds 350 g/m ² , not only will the effect be saturated, but too much superabsorbent polymer particles will cause a violation of the friction of small particles (a rustling sound).

(Packaging tablets) In order to prevent the superabsorbent polymer particles from coming out or to improve the shape-retaining properties of the absorber 56, an absorption member 50 formed by covering the absorber 56 with a packaging sheet 58 may be incorporated. As the packaging sheet 58, tissue paper, in particular, crepe paper, non-woven fabric, composite laminated non-woven fabric, a sheet with small holes and the like can be used. However, a sheet in which the superabsorbent polymer particles do not come out is desired. When non-woven fabric is used instead of crepe paper, a hydrophilic SMMS (spunbond/meltblown/meltblown/spunbond) nonwoven fabric is particularly preferred, and its material can be polypropylene, polyethylene/polypropylene, or the like.

As shown in FIG. 3, the packaging sheet 58 can be formed as a single sheet covering the entire absorbent body 56, or can be formed by plural sheets such as two upper and lower sheets to cover the entire absorbent body 56. The packaging sheet 58 can also be omitted.

The weight per unit area of the packaging sheet 58 is preferably 16 gsm or more, and more preferably 20 gsm or more. By making the weight per unit area of the packaging sheet 58 larger, the excrement or acid held by the absorber 56 can be prevented from permeating to prevent it from adhering to the wearer's skin and burdening the skin.

(Top film) The top sheet 30 is a sheet having liquid permeability, and for example, a nonwoven fabric with or without holes or a porous plastic sheet can be used. In addition, the raw fiber of the non-woven fabric is not particularly limited. For example, synthetic fibers such as olefins such as polyethylene or polypropylene, polyesters, and polyamides, regenerated fibers such as rayon or cuprammonic fibers, natural fibers such as cotton, or both may be used. The above mixed fiber, composite fiber, etc. In addition, the non-woven fabric can be manufactured by any processing. As a processing method, a well-known method can exemplify a spunlace method, a spun bond method, a hot rolling method, a melt blow method, a needle punch method, a hot air method, a point bonding method, etc. For example, if flexibility and drape are sought, the spunlace method is the preferred processing method, and if bulkiness and flexibility are sought, the hot rolling method is the preferred processing method.

The topsheet 30 extends from the front end to the rear end of the product in the front-rear direction, and extends to the side of the absorber 56 in the width direction WD. However, when the starting point of the rising wrinkle 60 described later is When the side edges are closer to the center side in the width direction, the width of the top sheet 30 may be shorter than the full width of the absorber 56 according to needs, and may be appropriately deformed.

The fiber diameter of the top sheet 30 can be arbitrarily determined, but it is preferably 4.0 dtex or more, and more preferably 5.0 dtex or more. In this way, by making the fiber diameter of the top sheet 30 thicker, the excrement can be quickly absorbed. As a result, it is possible to reduce the time that the excrement contacts the wearer's skin. In addition, it is possible to prevent excreta from accumulating on the front surface of the top sheet 30 and spreading over a wide range, so it is possible to reduce the area where excreta adheres to the wearer's skin. This can reduce the burden on the skin caused by the tendency of the excrement adhered to the top sheet 30 toward the alkaline side.

In addition, it is preferable that the top sheet 30 is composed of a plurality of layers, and the fiber diameter of the layer located on the skin side is made smaller than the fiber diameter of the layer located on the back side. By reducing the fiber diameter of the layer on the skin side, the skin feels good, so the burden on the wearer's skin can be reduced. In addition, by increasing the fiber diameter of the layer on the back side, excreta can be quickly absorbed.

Specifically, among the plural layers of the top sheet 30, the fiber diameter of the layer located on the skin side is preferably 2.5 dtex or less, and more preferably 1.7 dtex or less. In addition, the fiber diameter of the layer located on the back side is preferably 4.0 dtex or more, and more preferably 5.0 dtex or more. By setting the fiber diameter in such a range, the wearer can easily feel that the skin feels better and can quickly absorb excreta.

(Intermediate) In order to quickly move the liquid after passing through the top sheet 30 to the absorber 56, an intermediate sheet (also referred to as a "second sheet") 40 having a faster liquid permeability than the top sheet 30 may be provided. This intermediate sheet 40 is used for the purpose of quickly moving the liquid to the absorbent body 56 to improve the absorption performance of the absorbent body 56 and to prevent the phenomenon that the absorbed liquid "seeps back" from the absorbent body 56. The intermediate sheet 40 may also be omitted.

As the intermediate sheet 40, the same raw material as the top sheet 30, or spunlace nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, pulp nonwoven fabric, mixed sheet of pulp and rayon, point-bonded nonwoven fabric, or crepe paper can be exemplified. In particular, the hot air non-woven fabric is very fluffy, so it is preferable. For the hot-air nonwoven fabric, it is preferable to use a composite fiber with a core-sheath structure. In this case, the resin used for the core may be polypropylene (PP), but it is preferably polyester with high rigidity (PET). The thickness of the raw fiber of the nonwoven fabric is preferably 2.0 to 10 dtex. In order to make the nonwoven fabric bulky, it is preferable to use eccentric fibers, hollow fibers, or eccentric and hollow fibers whose core is not the center of all or part of the mixed fibers.

The intermediate sheet 40 in the illustrated example is shorter than the width of the absorber 56 and is arranged to the center, and may be provided over the entire width. In addition, the intermediate sheet 40 may be provided over the entire length of the diaper, or may be provided only in the middle portion including the excretion position as shown in the example.

The weight per unit area of the intermediate sheet 40 is preferably 20 gsm or more, and more preferably 30 gsm or more. If the body pressure of the wearer is applied to the absorbent article, a phenomenon of re-osmosis in which the excrement held by the absorbent body 56 moves toward the skin side may occur. As described above, by setting the weight per unit area of the intermediate sheet 40 to be large, it is possible to reduce the amount of excretion. In particular, if a part of the acid contained in the topsheet 30 is lost together with excretion and is contained in the absorbent body 56 to cause re-infiltration, the acid of the topsheet 30 may adhere to the wearer's skin. Burden the wearer's skin. Therefore, the weight per unit area of the intermediate sheet 40 can be increased to prevent the back-wetting, so as to reduce such a burden.

(Liquid-impermeable tablet) The liquid-impermeable sheet 11 is not particularly limited, but preferably has moisture permeability. As the liquid-impermeable sheet 11, for example, a microporous sheet obtained by a method obtained by kneading an inorganic filler in an olefin-based resin such as polyethylene or polypropylene and molding the sheet can be suitably used. Uniaxial or biaxial stretching. In addition, as the liquid-impermeable sheet 11, a non-woven fabric can be used as a base material to improve water resistance.

The liquid-impermeable sheet 11 is desirably the same as the absorber 56 in the front-rear direction LD and the width direction WD or extends over a wider range. However, when other water-shielding members are present, it can also be made according to the needs. The end portion of the absorber 56 is not covered in the front-rear direction LD and the width direction WD.

(Exterior non-woven fabric) The exterior non-woven fabric 12 covers the entire back side of the liquid-impermeable sheet 11 to give the outer surface of the product a cloth-like appearance. The exterior nonwoven fabric 12 is not particularly limited, and as raw material fibers, synthetic fibers such as olefin-based, polyester-based, and polyamide-based polyethylene, polypropylene, and synthetic fibers such as man-made fibers, cuprammonic fibers, and cotton can be used. Natural fibers and the like can be used as a processing method such as a spunlace method, a spunbond method, a hot rolling method, a hot air method, and a needle punching method. However, from the viewpoint of both skin feel and strength, long fiber nonwoven fabrics such as spunbond nonwoven fabric, SMS nonwoven fabric, and SMMS nonwoven fabric are preferred. In addition to using one piece of nonwoven fabric, plural pieces of nonwoven fabric can also be used in an overlapping manner. In the latter case, it is preferable to bond the nonwoven fabrics with a hot-melt adhesive. When a non-woven fabric is used, the weight per unit area of the fiber is desirably 10 to 50 g/m ² , and particularly desirably 15 to 30 g/m ² .

(Wrinkle up) In order to prevent the excrement moving laterally on the top sheet 30, the so-called side leakage prevention is preferably provided with standing folds 60 standing on the wearer's skin side on both sides of the surface width direction WD. Of course, the standing wrinkle 60 can also be omitted.

When the raised pleats 60 are used, the structure is not particularly limited, and various known structures can be used. The standing wrinkle 60 illustrated in the figure is fixed in the wrinkled sheet 62 by the wrinkled sheet 62 substantially continuous in the width direction WD and the elongated state extending in the front-rear direction LD. The elastic member 63 is folded. As the crumpled sheet 62, a water-repellent nonwoven fabric can be used, and as the crumpled elastic member 63, a rubber thread or the like can be used. As shown in FIGS. 1 and 12, a plurality of elastic members may be provided, and one elastic member may be provided.

The inner surface of the wrinkled sheet 62 has a starting point in the width direction WD on the side of the top sheet 30, and the outer portion in the width direction from the starting point is joined to each side wing by a hot-melt adhesive or the like The inner surface of the SF, that is, the side portion of the liquid-impermeable sheet 11 and the side portion of the exterior nonwoven fabric 12 located on the outer side in the width direction in the illustrated example.

Around the leg, it is more inward in the width direction than the joining starting point of the raised wrinkle 60, and both ends in the front-rear direction of the product are fixed to the top sheet 30, but the part in between is a non-fixed free part. The contractile force of the elastic member 63 stands up and becomes tightly attached to the body surface.

(End wing, side wing) The sticker-type disposable diaper illustrated in the figure has a pair of end flaps EF and a pair of side flaps SF that extend from the front and rear sides of the absorber 56 and have no absorber, respectively 56. The pair of side wings SF also extend laterally from both side edges of the absorber 56 without the absorber 56. The side wing portion SF, as shown in the example, may be composed of a raw material (exterior nonwoven fabric 12) that is continuous from the portion having the absorber 56, or may be formed by mounting other raw materials.

(Flat wrinkle) Each side wing portion SF is fixed with a side elastic member 64 composed of an elongated elastic member such as a rubber wire or the like in an extended state extending in the front-rear direction LD, thereby forming a portion around the leg portion of each side wing portion SF Flat folds. As shown in the example, the side elastic member 64 can be provided on the side flaps in addition to the widthwise outer side of the wrinkled sheet 62 and the liquid-impermeable sheet 11 in the vicinity of the starting point of the joint of the wrinkled sheet 62 Between the liquid-impermeable sheet 11 and the exterior nonwoven fabric 12 in the part SF. The side elastic member 64 may be provided with only one on each side in addition to providing a plurality of sides on each side as shown in the example.

The flat wrinkle is a portion where the contraction force of the side elastic member 64 acts (in the figure, the side elastic member 64 is illustrated). Thereby, in addition to the form in which the side elastic member 64 exists only in the part of the plane wrinkle, it also includes the following structure: although there are sides on the front side, the rear side, or both sides of the plane wrinkle The elastic member 64, but the side elastic member 64 is finely cut at one or more parts other than the flat wrinkled part, or is not fixed to the clip, or the two are implemented together, so that the contraction force does not It acts on a portion other than the flat wrinkle (essentially, it is equivalent to not providing an elastic member) and causes the contraction force of the side elastic member 64 to act only on the flat wrinkle.

(Link belt) The side flap portions SF in the back side portion B are provided with connecting straps 13 that are detachably connected to the outer surface of the ventral portion F, respectively. When wearing a diaper, the connecting belt 13 is wound from both sides of the waist to the outer surface of the abdominal portion F, and the connecting portion 13A of the connecting belt 13 is connected to an appropriate portion of the outer surface of the abdominal portion F.

The structure of the connecting belt 13 is not particularly limited, and in the illustrated example, it has a base end portion 13C fixed to the side wing portion SF, and an extension portion 13B extending from the base end portion 13C outward in the width direction WD. The extending portion 13B has a sheet base material and a connecting portion 13A provided in the widthwise middle portion of the sheet base material and connected to the outer surface of the ventral side, and the portion closer to the tip side than the connecting portion 13A becomes pinched unit.

As the connecting portion 13A, in addition to a hook material (protrusion material) provided with a mechanical fastener (face fastener), an adhesive layer may be provided. The hook material has a plurality of engaging protrusions on its connecting surface. As the shape of the engaging protrusions, there are (A) Japanese ray shape, (B) J shape, (C) mushroom shape, (D) T shape, (E) Double J-shaped (a shape formed by combining J-shaped structures back-to-back), etc., but may be any shape.

In addition, as the sheet base material formed from the base end portion 13C to the extension portion 13B, nonwoven fabric, plastic film, composite laminated nonwoven fabric, paper, or a composite material of these materials can be used. However, the fineness is 1.0 to 3.5 dtex, Spunbond nonwoven fabric, hot air nonwoven fabric, or spunlace nonwoven fabric having a weight per unit area of 20 to 100 g/m ² and a thickness of 1 mm or less is preferable.

(Target) Preferably, a target portion is provided at the connecting portion of the abdominal portion F connected to the connecting belt 13. The target portion, as shown in the example, can be provided by attaching the target piece 20 for facilitating connection to the outer surface of the abdominal part F. For the target sheet 20, when the connecting portion 13A is a hook material, a surface of a sheet base material composed of a plastic film or a non-woven fabric may be provided with a plurality of looped wires that can be wound around the hook protrusion of the hook material For the target sheet, when the connecting portion 13A is an adhesive material layer, a target sheet subjected to a peeling treatment on the surface of a sheet base composed of a plastic film with a smooth surface can be used such that it is rich in adhesiveness. In addition, in the case where the connecting portion connected to the connecting belt 13 in the ventral portion F is made of non-woven fabric, for example, in the case of the exterior non-woven fabric 12 shown in the figure, the target 20 may be omitted and the hook material may be wound It is connected to the fibers of the nonwoven fabric 12 on the outside. In this case, in addition to providing the target sheet 20 as a mark between the exterior nonwoven fabric 12 and the liquid-impermeable sheet 11, the mark may be printed on the outer surface of the exterior nonwoven fabric 12 or the liquid-impermeable sheet 11.

(Wing portion) As shown in FIGS. 1 and 2, the present adhesive-type disposable diaper has a crotch portion M extending from the middle of the front-back direction LD of the abdominal portion F to the middle of the front-back direction LD of the back portion B. In addition, the ventral portion F and the dorsal portion B have a wing portion WP that protrudes more outward in the width direction WD than the crotch portion M. The lower edge of the wing portion of the ventral portion F extends obliquely to the outside as the front end of the side edge of the crotch portion M toward the front; the lower edge of the wing portion of the dorsal portion B follows the self-crotch portion The rear end of the side edge of M extends obliquely outward toward the rear. The side edge of the wing portion WP is linear in the illustrated example, but it is not limited to this, and other known shapes can be adopted. The size of the crotch portion M in the front-rear direction LD can be appropriately determined, and can be set to be about 1.2 to 1.4 times the minimum width M _X of the crotch portion M. In the case of infant use, crotch longitudinal direction LD of the size M M _Y is the degree of 10 ~ 30cm.

(Water-soluble acid and hydrophilic agent) The topsheet 30 of the absorbent article contains a water-soluble acid. The topsheet 30 preferably further contains a hydrophilic agent. In addition, it is preferable to include a water-soluble acid not only in the top sheet 30, but also in either one of the intermediate sheet 40 and the packaging sheet 58, or in both the intermediate sheet 40 and the packaging sheet 58. In this case, it is preferable to also contain a water-soluble acid and a hydrophilic agent. In the following description, the water-soluble acid (and hydrophilic agent) contained in the top sheet 30 will be described. However, unless otherwise specified, the intermediate sheet 40 and the packaging sheet 58 have the same configuration.

The water-soluble acid can be used without particular limitation, but an acid having a pH of 2 to 4 is suitable. In the case where the pH value is less than 2, when the acid adheres to the wearer's skin, it will cause a burden on the skin and is unfavorable. In addition, in the case where the pH value is greater than 4, it is difficult and unfavorable to effectively suppress the excretion from tilting toward the alkaline side. Specific examples of the water-soluble acid include citric acid, tartaric acid, malic acid, and lactic acid. Particularly preferred are citric acid and lactic acid that are safe enough to be used as food additives. The reason why this water-soluble acid is not likely to be lost to the absorber side even after repeated urination is repeated, so it is preferably fixed to the fiber constituting the top sheet 30 by coating, but it may be In the diaper processing machine, the top sheet 30 is fixed on the in line at the time of diaper manufacturing by spray coating or other methods. In addition, in general, the water-soluble acid is fixed in the gap between the fibers constituting the nonwoven fabric without relying on chemical bonding. Therefore, urination may cause loss from the non-woven fabric together with urine. Therefore, it is also possible to apply the water-soluble acid and the hydrophilic agent together to the non-woven fabric fiber, so that it is not easily lost even when urinating repeatedly.

The hydrophilic agent used in the aforementioned application can be used without particular limitation, and examples include typical hydrophilic agents of various surfactants (anionic, cationic, zwitterionic, and nonionic). Specifically, for example, fatty acid esters of polyglycerin fatty acid esters, polyether-polyester block copolymers, polyether-modified silicones, and ethylene oxide addition polyols can be used. This hydrophilic agent prevents acid from being lost to the side of the absorber 56 when urinating repeatedly, so it is suitable for fixing by coating on the fibers constituting the topsheet 30, but it can also be used in diaper processing machines during diaper manufacturing The production line is fixed on the top sheet 30 by spraying or other methods.

The top sheet 30 manufactured as described above is in a state where water-soluble acid has adhered to the outer surface of the fibers constituting the top sheet 30. In parallel with this, a state in which a water-soluble acid is filled in the gap between the plurality of fibers constituting the top sheet 30 may be made. Furthermore, if the water-soluble acid is impregnated into the fiber itself constituting the topsheet 30, it is not easy to cause the water-soluble acid to be lost even if it is excreted multiple times, which is suitable.

For the topsheet 30 containing a water-soluble acid and a hydrophilic agent, the following artificial urine drip test is performed, and the first measurement result may be 10 points, the second measurement result may be 10 points, and the third The top sheet 30 having a measurement result of 9 points or more is contained in the absorbent article. (Dropping test method of artificial urine) (1) Place the top sheet 30 containing the hydrophilic agent on the filter paper that overlaps 10 sheets, and place the metal jig 70 made of 10 holes on the top sheet 30. In addition, in this test, in order to confirm whether the hydrophilic agent contained in the top sheet 30 is not easily lost when excreted repeatedly, the top sheet 30 used in this test does not necessarily contain a water-soluble acid. (2) (The first measurement) Using a microdropper, 1 mL of artificial urine (artificial urine to which the following pigment has been added) was dropped into each well (that is, 10 mL of artificial urine was added to 10 wells). After the artificial urine was dropped, it was confirmed within 2 seconds whether the non-woven fabric (called the top sheet, hereinafter, the same in the description of the dropping test method) had absorbed the artificial urine. When the artificial urine remains on the nonwoven fabric (usually, when the artificial urine becomes spherical and is placed on the nonwoven fabric), it is recorded that the nonwoven fabric does not absorb the artificial urine. On the other hand, when the artificial urine did not remain on the nonwoven fabric, it was recorded that the nonwoven fabric absorbed artificial urine. This recording operation is performed separately for 10 holes. That is, within 2 seconds of recording, several of the 10 places are places where artificial urine has passed through the non-woven fabric. Then, the absorbed holes were counted as 1 point, and the non-absorbed holes were counted as 0 points, and the total number of points of 10 holes was recorded. (3) (second measurement) After dropping artificial urine (artificial urine to which the following pigment has been added) from the above (2), wait for 3 minutes to elapse, and after 3 minutes, use a micro-dropper again and drop 1 mL of artificial urine into each well . Then, the total points are recorded using the same method as in (2) above. (4) (The third measurement) After dropping artificial urine (artificial urine to which the following pigment has been added) from the above (3), wait for 6 minutes, and after 6 minutes, use a glass dropper to drop 500 μL of artificial urine into each well . Then, the total points are recorded using the same method as in (2) above. (5) In the recording results of the aforementioned (2) to (4), the first measurement result may be 10 points, the second measurement result may be 10 points, and the third measurement result may be 9 points or more The topsheet 30 is contained in the absorbent article. Even when excreted multiple times, it can be judged that the hydrophilic agent is not easily lost. (filter paper) As the filter paper used in the aforementioned test, for example, FILTER PAPER of ADVENTEC company of 250 mm×250 mm square shape can be used. (Metal fixture) As the metal jig 70, the following jig is used. A rectangle with a width of 210 mm, a length of 50 mm, and a thickness of 5 mm, and a weight of 400 g; a hole 71 with a diameter of 15 mm, with 4 mm intervals in the width direction and the length direction, 10 holes are opened at equal intervals. (Artificial urine) As the artificial urine used in the aforementioned test, the following artificial urine was used. Artificial urine composed of 2wt% urea, 0.8wt% sodium chloride, 0.03wt% calcium chloride dihydrate, 0.08wt% magnesium sulfate heptahydrate, and 97.09wt% ion exchanged water. (pigment) About 5 g of KIRIYA's edible cyan No. 1 (Brilliant Blue FCF) (packing style: powder) was dissolved and prepared in about 300 ml of the above-mentioned artificial urine. (dropper) As the microdropper used in the artificial urine dropping test, for example, Biohit Proline Pipette 100 to 1000 μ1 (model number: 720050) can be used. In addition, as the glass dropper used in the artificial urine dropping test, for example, 5 ml of KOMA5 (model number: 0801-04) of MARUEMU Corporation can be used.

The hydrophilic agent is attached to the outer surface of the fibers constituting the topsheet 30 together with the water-soluble acid. The hydrophilic agent may be made to fill the gap between the fibers constituting the top sheet 30 together with the water-soluble acid. In addition, if the water-soluble acid and the hydrophilic agent penetrate the interior of the fiber constituting the topsheet 30, the water-soluble acid and the hydrophilic agent will not be easily lost even if excreted multiple times, so the excrement is continuously suppressed The effect toward the alkaline side is high.

When the wearer of the absorbent article excretes, the excrement comes into contact with the water-soluble acid contained in the topsheet 30, thereby suppressing the tendency of the excrement toward the alkaline side. For example, if the wearer urinates, the urea remaining in the topsheet 30 will be hydrolyzed by urease to form Armonia over time, and the water-soluble acid contained in the topsheet 30 and this Amor Nia reaction, while preventing the pH of excreta to tend to the alkaline side. In detail, the aforementioned water-soluble acid suppresses the production of Armonia and neutralizes the produced Armonia. In this way, the excretion does not tend to the alkaline side due to the water-soluble acid, and even if the excretion is allowed to permeate and continue to contact the wearer's skin, the burden on the skin will be reduced.

In addition, if the water-soluble acid contained in the top sheet 30 is lost to the absorbent body 56 due to excretion, the tendency of excrement to be directed toward the alkaline side cannot be effectively prevented during the second and subsequent excretion . In particular, a disposable diaper or the like worn at bedtime is expected to be excreted multiple times during wearing, so it is highly necessary to suppress the occurrence of such inconvenience. Therefore, the topsheet 30 concerning the present invention contains a hydrophilic agent. With this hydrophilic agent, the water-soluble acid is firmly fixed to the fibers constituting the topsheet 30, and even if excreted multiple times, the water-soluble acid is not easily lost, and the excrement can be continuously suppressed toward the alkaline side. tendency.

The formulation amount of the water-soluble acid with respect to the top sheet 30 is preferably 0.02% to 0.07%, and more preferably 0.03% to 0.05%. In the case where the blending amount is more than 0.07%, when the acid adheres to the wearer's skin, it will cause a burden on the skin, which is unfavorable. In addition, in the case where the blending amount is less than 0.02%, it is difficult and unfavorable to effectively suppress the excreta tending to the alkaline side. The amount of the hydrophilic agent blended in the top sheet 30 is preferably 0.3% to 0.5%, and more preferably 0.4% to 0.5%. In the case where the dosage is more than 0.5%, the cost of the drug will make the original price of the product higher, and it is easy to seep back when the body pressure of the wearer after urination is applied. In addition, when the blending amount is less than 0.3%, the binding between the water-soluble acid and the fibers constituting the topsheet 30 is weak, so that multiple excretion may cause the water-soluble acid to be easily lost, and the urine may not be able to Leakage through non-woven fabric. The mixing ratio of the water-soluble acid and the hydrophilic agent is preferably 1:7 to 1:20, and more preferably 1:15. If it exceeds this range, it will affect the hydrophilicity of the nonwoven fabric, which is disadvantageous.

When the water-soluble acid is included in the top sheet 30, the effect of reducing the burden on the wearer's skin is high. The top sheet 30 is a top sheet that directly contacts the wearer's skin (for example, the skin of the buttocks). If excretion caused by the excretion attached to the top sheet 30 tends to the alkaline side, the continuous contact between the skin and the excrement will Skin burden. Therefore, by including the water-soluble acid in the topsheet 30, the tendency toward the alkaline side can be suppressed, and the burden on the skin of the wearer can be reduced.

In addition, when the water-soluble acid is contained in the top sheet 30, the acid contained in the top sheet 30 may cause a burden on the wearer's skin. By using a near-neutral acid and reducing the amount of acid added, the burden on the skin caused by the acid can be reduced, but in this case, there is a disadvantage that the tendency of the excrement toward the alkaline side cannot be effectively suppressed. Therefore, in order to solve such a problem, it is preferable that the top sheet 30 be formed in a plurality of layers. The layer on the skin side does not contain water-soluble acid (or a small amount even if included), and the layer on the back side contains water-soluble Acid and hydrophilic agent. For example, the top sheet 30 may have a two-layer structure. The layer (upper layer) on the skin side does not contain water-soluble acids, and the layer (lower layer) on the back side contains water-soluble acids and a hydrophilic agent. When the topsheet 30 has a structure of three layers or more, the layer (uppermost layer) on the side closest to the skin may not contain water-soluble acid, and may be on any layer or all of the layers on the back side than the uppermost layer. The layer contains a water-soluble acid and a hydrophilic agent. In FIG. 3, it is exemplified that the top sheet 30 has a two-layer structure, the layer (upper layer) on the skin side is represented by 30U, and the layer (lower layer) on the back side is represented by 30D. The upper layer 30U does not contain a water-soluble acid and a hydrophilic agent, and the lower layer 30D contains a water-soluble acid and a hydrophilic agent.

In addition, as described above, it is preferable that the upper layer 30U does not contain a water-soluble acid, but the hydrophilic agent does not burden the skin, so the upper layer 30U may contain a hydrophilic agent. In the case where the upper layer 30U and the lower layer 30D both contain a hydrophilic agent will make the manufacturing process easier, the upper layer 30U may also contain a hydrophilic agent.

Among them, when it is important to prevent the alkalinization of the top sheet 30, especially the part that contacts the skin, in order to reduce the burden on the skin caused by Armonia, the layer on the skin side of the top sheet 30 is intentionally made It is also effective to include water-soluble acids.

In addition, the top sheet 30 having a special structure such as the present invention, that is, the top sheet 30 containing no water-soluble acid in the upper layer 30U and containing the water-soluble acid in the lower layer 30D can be obtained by, for example, the following (1) or ( 2) Method to manufacture. (1) For example, first, raw material cotton (a fiber used as a raw material, the same below) which is a raw material of a layer on the skin side is manufactured through the steps of raw material feeding, heating, melting, and pressing. In addition, raw material cotton which is the raw material of the layer on the back side is manufactured through the steps of raw material feeding, heating, melting, pressing, and cooling, followed by acid coating. Then, on a plurality of production lines of the nonwoven fabric manufacturing apparatus (for example, in the case of manufacturing a top sheet of a two-layer structure, two production lines for producing a layer on the skin side and two production lines for producing a layer on the back side), respectively The raw cotton which becomes the raw material of the layer located on the skin side, and the raw cotton which becomes the raw material of the layer located on the back side are supplied. After that, primary fiber separation, metering and blending, secondary fiber separation, fiber cluster formation (storage of secondary fibers that have been separated from the secondary fiber are evenly stored in the box) and fiber web forming (by borrowing) The step of forming the raw cotton stored in the box into a sheet shape by a carding machine. Then, the sheets manufactured by forming the fiber web are overlapped and formed into a plurality of layers, which are combined by a heat welding process, and then subjected to the steps of foreign matter mixing inspection and winding. In addition, the above description exemplifies a method of manufacturing a plurality of layers of nonwoven fabric using a hot air method, but it can also be produced using a manufacturing method different from the welding method of nonwoven fabric. As other manufacturing methods, a spunlace method, a spun bond method, a hot rolling method, a melt blow method, a needle punch method, a point bonding method, etc. can be exemplified. In addition, in the above description, when producing raw cotton which is a raw material of the layer on the back side, the hydrophilic agent may be applied together with the acid. In parallel with this, the hydrophilic agent may be applied at the timing after the cooling when the raw cotton that is the raw material of the layer on the skin side is manufactured. (2) For example, in the step of manufacturing a diaper using a diaper processing machine, only on the lower layer side of the topsheet 30 before being attached to the diaper body, an acidic component is added by spraying.

The intermediate sheet 40 can also contain a water-soluble acid. Since the intermediate sheet 40 does not directly contact the wearer's skin, by including a water-soluble acid in the intermediate sheet 40, it is possible to prevent the acid from burdening the wearer's skin. Also, in general, the intermediate sheet 40 is fluffy, so when the excrement reaches the absorber 56, there will be more excretions remaining in the intermediate sheet 40 than in the top sheet 30 or the packaging sheet 58 The amount of excrement tends to be more. Therefore, the inclusion of a water-soluble acid in the intermediate sheet 40 suppresses the alkalization of the excrement remaining in the intermediate sheet 40, thereby reducing the burden on the skin when the excrement remaining in the intermediate sheet 40 re-permeates .

The packaging sheet 58 can also contain a water-soluble acid. Since the packaging sheet 58 does not directly contact the wearer's skin, the water-soluble acid contained in the packaging sheet 58 can prevent the acid from burdening the wearer's skin. In addition, since the packaging sheet 58 covers the absorber 56, there is a greater chance of contact with the absorber 56 holding fecal matter. Therefore, the acid contained in the packaging sheet 58 acts on the excrement held by the absorbent body 56 for a longer period of time, so that the tendency of the excrement held by the absorbent body 56 toward the alkaline side can be effectively suppressed. In addition, the packaging sheet 58 may contain a water-soluble acid throughout the packaging sheet 58. When considering the purpose of reducing the burden on the wearer's skin, it is preferable that at least the packaging sheet 58 is more than the absorber 56 The skin-side part contains water-soluble acids. In addition, the hydrophilic agent is also similar, and is preferably provided on the skin side of the absorber 56.

It is important to include a water-soluble acid in the topsheet 30 that has a high influence on the wearer's skin. That is, the topsheet 30 directly contacts the skin, so it is effective to suppress the alkalization of the excrement attached to the topsheet 30. From this point of view, it is important that at least the topsheet 30 contains a water-soluble acid. . However, in addition to this, any one of the sheets of the intermediate sheet 40 and the packaging sheet 58 may be selected to contain a water-soluble acid, or all sheets in these groups may contain a water-soluble acid. From the viewpoint of the original price of the product, it is preferable to include the water-soluble acid only in the top sheet 30; as a sheet other than the top sheet 30, in particular, the inclusion of the water-soluble acid in the intermediate sheet 40 will be easy to manufacture and from the viewpoint of the original price Favorable. On the other hand, from the viewpoint of suppressing alkalization, it is preferable to include a water-soluble acid in more sheets.

(Scope of additional acid) The plane range of the top sheet 30, the middle sheet 40, and the packaging sheet 58 containing a water-soluble acid is preferably a predictable diffusion range of excreta. When the absorbent article is a disposable diaper as shown in the figure, it is preferable to add acid to at least the crotch portion M when considering the position of the wearer's excretory opening (urination opening, anus, etc.). When the amount of excrement is large, or when excretion is performed a plurality of times, it is expected that the excrement will spread to a wide range, so it is desirable to add acid to the entire top sheet 30. Even in the middle sheet 40 or the packaging sheet 58, it is preferable to add acid at the same position as the top sheet 30. The hydrophilic agent is preferably added in the same range as the acid.

(Experimental example) Prepare the following 2 experimental materials. (1) Material 1: Hot air nonwoven fabric (diaper topsheet) with a weight per unit area of 20 gsm, and has a two-layer structure with a skin surface of 2.0 dtex and a back surface of 3.3 dtex. As the raw material of the non-woven fabric, a composite fiber of polyethylene and polyethylene terephthalate is used. This hot-air nonwoven fabric contains a nonionic surfactant as a hydrophilic agent. The content of the hydrophilic agent is 0.4% relative to the weight of the non-woven fabric. (2) Material 2: Hot air non-woven fabric (diaper topsheet) with a weight per unit area of 20 gsm and a single-layer structure of 2.2 dtex. As the raw material of the non-woven fabric, a composite fiber of polyethylene and polyethylene terephthalate is used. This hot-air nonwoven fabric contains a nonionic surfactant as a hydrophilic agent and citric acid as a water-soluble acid, respectively. The content of the hydrophilic agent is 0.4% relative to the weight of the non-woven fabric, and the content of the water-soluble acid is 0.05% relative to the weight of the non-woven fabric.

The experiment was carried out in a laboratory at 22.1°C. First, 10 pieces of filter paper (250 mm×250 mm square ADVENTEC FILTER PAPER) were stacked, and the aforementioned material 1 was placed thereon. Then, a circle with a diameter of 20 mm was drawn on the aforementioned material 1 with a marker, and the inside of the circle was used as a measurement point. More specifically, six circles of the material are drawn on the material 1, and the inside of each circle is defined as the measurement points A to F.

Next, the aforementioned material 2 was placed on the same 10 pieces of filter paper as described above. Then, a circle with a diameter of 20 mm was drawn on the aforementioned material 2 with a marker pen, and the inside of the circle was used as a measurement point. In more detail, the said circle|circle of 6 places is drawn on the said material 2, and the inside of each circle is set to the measurement position G-L.

Next, 100 μL of artificial urine was dripped at the measurement points A to C of the material 1 respectively. In addition, the components of the aforementioned artificial urine are 2% by weight of urea, 0.8% by weight of sodium chloride, 0.03% by weight of calcium chloride dihydrate, 0.08% by weight of magnesium sulfate heptahydrate, and 97.09% by weight of ion-exchanged water. Then, 1 minute later, the pH of the surface of the measurement sites A to C of the material 1 was measured using a contact-type pH meter (manufactured by HORIBA, model #6261-10C) (the first measurement).

Thereafter, 100 μL of artificial urine was dripped separately at the measurement points A to C of the material 1, and after 1 minute, the pH of the surface of the measurement points A to C of the material 1 was measured using the aforementioned contact-type pH meter (the first Secondary measurement). Furthermore, 100 μL of artificial urine was dripped separately at the measurement points A to C of the material 1, and after 1 minute, the pH of the surface of the measurement points A to C of the material 1 was measured separately using the aforementioned contact-type pH meter (third Measurement).

Next, the measurement points D to F of the material 1 are also measured under the same conditions as the aforementioned first measurement to third measurement. In addition, for the measurement points D to F, the amount of artificial urine dropped per time was not 100 μL, but was set to 500 μL.

Next, the measurement points G to I of the material 2 are also measured under the same conditions as the aforementioned first measurement to third measurement. In addition, for the measurement points G to I, the dropping amount of artificial urine per one time was set to 100 μL.

Furthermore, the measurement locations J to L of the material 2 are also measured under the same conditions as the aforementioned first measurement to third measurement. In addition, for the measurement points J to L, the amount of artificial urine dropped per time was set to 500 μL.

The test results are shown in Table 1, Figure 6, and Figure 7 below. [Table 1]

(Investigation) It can be seen that the measurement points G to L prepared with citric acid tend to have a lower pH value than the measurement points A to F without citric acid. In addition, it can be seen that in the measurement points G to L where the hydrophilic agent and the citric acid are formulated, even when artificial urine is dropped three times, the alkalization hardly progresses. It is believed that the citric acid is firmly held on the fibers of the hot air non-woven fabric by the hydrophilic agent, and even if urination is performed multiple times, it will not cause loss.

(Effect of the present invention compared with the prior art) According to the absorbent article of the present invention, even after the wearer repeats the secondary excretion, acid is likely to remain in the topsheet 30, so that the alkalinization suppressing effect by acid can be maintained. In addition, the wearer of the absorbent article does not excrete once, and the water-soluble acid contained in the topsheet 30 does not continuously contact the wearer's skin (for example, the acid is added to the topsheet 30). In the lower layer), this can reduce the burden on the skin. Furthermore, by setting at least one of the intermediate sheet 40 and the packaging sheet 58 to have a large weight per unit area, it is possible to reduce the possibility of fecal matter and acid repermeating and contacting the wearer's skin even at the site where body pressure is applied .

Since it is not necessary to provide a convex portion on the top sheet 30 as in the aforementioned Patent Document 1, the degree of freedom of design of the absorbent article is high. In addition, since it is not necessary to specifically limit the portion where the acid is formulated as in the aforementioned Patent Document 1, the manufacturing is also easy. Also, instead of using fumaric acid, which is not easily dissolved in water, as in the aforementioned Patent Document 2, but using a water-soluble acid, it is easy to apply the hydrophilic agent to the sheet and manufacture is easy. In addition, it is advantageous that malic acid, which is more irritating to the skin than citric acid, as in the aforementioned Patent Document 3, is not used.

(other) There is also a possibility that the excrement inside the absorber 56 may re-infiltrate. Taking this into consideration, it is also effective to prevent the excretion present inside the absorber 56 from becoming alkaline. Therefore, the inclusion of water-soluble acid in the absorber 56 itself (for example, the superabsorbent polymers of the absorber) is also effective for reducing the burden on the skin.

(acid) In the above description, a water-soluble acid is taken as an example, but the acid that can be contained in the top sheet 30 is not limited to a water-soluble acid. That is, if the affinity with the hydrophilic agent is not considered, the topsheet 30 may contain a poorly soluble acid such as fumaric acid.

(Excrement) As the excrement in the present invention, urine, defecation (especially soft stool), menstrual blood, etc. can be exemplified. In particular, it is effective for suppressing alkalization of excretion other than solid-shaped feces among excreta. In urine, urease and other decomposing enzymes hydrolyze the urea contained in the urine into Armonia to make excreta alkaline, which is suppressed by water-soluble acids. In soft stools, urease and other decomposing enzymes hydrolyze the urea contained in the soft stool into Armonia and make the excretion alkaline, which is suppressed by water-soluble acids.

>Explanation of terms in the manual> As long as there is nothing specifically described in the description, the following terms in the description have the following meanings.

・The “front-back direction” refers to the direction (longitudinal direction) indicated by the symbol LD in the figure, and the “width direction” refers to the direction (left-right direction) indicated by the symbol WD in the figure, and the front-rear direction is orthogonal to the width direction.

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

・"Elongation" refers to the value when the natural length is set to 100%. For example, an elongation of 200% means the same meaning as an elongation of 2 times.

・"Weight per unit area" is measured as follows. The sample or test piece is prepared for drying and placed in a standard state (temperature of the test site is 23 ± 1 ℃, relative humidity is 50 ± 2%) in the test room or device to make it into a constant state. Pre-drying refers to making the sample or test piece constant in an environment with a temperature of 100°C. In addition, for fibers with a legal moisture content of 0.0%, preliminary drying is not required. Using a template for sample selection (100 mm×100 mm), a sample with a size of 100 mm×100 mm is cut from the test piece in a state where it becomes constant. Measure the weight of the sample and multiply it by 100 times to calculate the weight per square meter as the weight per unit area.

・"Thickness" is automatically measured using an automatic thickness measuring device (KES-G5 portable compression measurement program) under a load of 0.098N/cm ² and a pressurized area of 2cm ² .

・"Water absorption" is measured in accordance with JIS K7223-1996 "Test method for water absorption of super absorbent resin".

・"Water absorption speed" is "time to end point" when JIS K 7224-1996 "Test method for water absorption speed of superabsorbent resin" is performed using 2 g of superabsorbent polymer and 50 g of physiological saline.

・In the absence of the environmental conditions in the test or measurement, the test or measurement is in a test room or device in a standard state (temperature of 23±1℃ and relative humidity of 50±2% at the test site) Carried out within.

・The dimensions of each part refer to the dimensions in the unfolded state, not in the natural long state, unless otherwise specified.

[Industry availability] The present invention can be applied to absorbent articles such as pants-type disposable pads, pad-type disposable diapers, diapers, and sanitary napkins, in addition to the adhesive disposable diapers as in the above examples. It is particularly preferable to apply to each of the aforementioned disposable diapers.

11‧‧‧Liquid-impermeable sheet 12‧‧‧Non-woven fabric 13‧‧‧Linking tape 13A‧‧‧Linking part 13B‧‧‧Extending part 13C‧‧‧Base end part 20‧‧‧Target 30‧‧ ‧Top sheet 30U‧‧‧Upper layer 30D‧‧‧Lower layer 40‧‧‧Intermediate sheet 50‧‧‧Absorbent part 56‧‧‧Absorbent body 58‧‧‧Packing sheet 60‧‧‧Rise wrinkle 62‧‧‧ Folding piece 63‧‧‧Wrinkled elastic member 64‧‧‧ Side elastic member 70‧‧‧Metal jig 71‧‧‧ Hole B‧‧‧Back part F‧‧‧Ventral part LD‧‧‧ size EF‧‧‧ end portions flanking wings SF‧‧‧ WP‧ front-rear direction widthwise direction WD‧‧‧ M‧‧‧ crotch M _X ‧‧‧ minimum crotch width of the crotch M _Y ‧‧‧ ‧‧Front part L‧‧‧The full length of the diaper X‧‧‧The full width of the diaper except the connecting belt 6-6, 7-7, 8-8, 9-9 ‧‧‧

FIG. 1 is a plan view showing the inner surface of the stick-on disposable diaper in the unfolded state of the diaper. Fig. 2 is a plan view showing the outer surface of the stick-on disposable diaper in the unfolded state of the diaper. Fig. 3 is a cross-sectional view taken along line 6-6 in Fig. 1. 4 is a cross-sectional view taken along line 7-7 in FIG. 5(a) is a cross-sectional view taken along line 8-8 in FIG. 1, and FIG. 5(b) is a cross-sectional view taken along line 9-9 in FIG. FIG. 6 is a graph showing the results of the experiment, showing changes in pH when 100 μL of artificial urine was dripped once to the measurement points A to C, and G to I three times. FIG. 7 is a graph showing the results of the experiment, showing the change in pH when 500 μL of artificial urine was dropped to the measurement points D to F and J to L three times. FIG. 8(a) is a plan view of a metal fixture, and FIG. 8(b) is a perspective view of a metal fixture.

Domestic storage information (please note in order of storage institution, date, number) no

Overseas hosting information (please note in order of hosting country, institution, date, number) no

11‧‧‧ liquid-impermeable tablets

12‧‧‧Outerwear Nonwoven

30‧‧‧Top film

30U‧‧‧Upper

30D‧‧‧Lower

40‧‧‧intermediate

50‧‧‧absorbent parts

56‧‧‧Absorber

58‧‧‧Packing tablets

60‧‧‧Erect wrinkles

62‧‧‧Crumpled tablets

63‧‧‧ wrinkled elastic member

64‧‧‧side elastic member

Claims (12)

An absorbent article having a top sheet provided on the skin side and an absorber provided on the back side of the top sheet. The absorbent article is characterized by: The aforementioned top sheet is composed of a plurality of layers; Among the plurality of layers, the layer on the skin side contains no acid, and the layer on the back side contains acid. The absorbent article according to claim 1, wherein the acid contained in the top sheet is a water-soluble acid; The top sheet contains the water-soluble acid and the hydrophilic agent. The absorbent article according to claim 2, wherein the hydrophilic agent includes polyglycerin fatty acid ester, polyether-polyester block copolymer, polyether modified silicone, or polyoxyethylene addition Fatty acid ester of alcohol, or a combination of these. The absorbent article according to claim 2 or 3, wherein the topsheet containing the water-soluble acid and the hydrophilic agent, in the artificial urine dropping test, the first measurement result is 10 points, the second The measurement result is 10 points and the third measurement result is more than 9 points. The absorbent article according to any one of claims 1 to 4, wherein an intermediate sheet is provided between the top sheet and the absorbent body; The aforementioned intermediate sheet contains a water-soluble acid and a hydrophilic agent. The absorbent article according to any one of claims 1 to 5, wherein a packaging sheet covering the aforementioned absorber is provided; The aforementioned packaging tablet contains a water-soluble acid and a hydrophilic agent. The absorbent article according to any one of claims 1 to 6, wherein the fiber diameter of the top sheet is 4.0 dtex or more. The absorbent article according to any one of claims 1 to 6, wherein in the plurality of layers of the top sheet, the fiber diameter of the layer on the skin side is smaller than the fiber diameter of the layer on the back side . The absorbent article according to claim 8, wherein, among the plurality of layers of the top sheet, the fiber diameter of the layer on the skin side is 2.5 dtex or less, and the fiber diameter of the layer on the back side is 4.0 dtex the above. The absorbent article according to any one of claims 1 to 9, wherein an intermediate sheet is provided between the top sheet and the absorbent body; The weight per unit area of the intermediate sheet is 20 gsm or more. The absorbent article according to any one of claims 1 to 10, wherein a packaging sheet covering the aforementioned absorber is provided; The weight per unit area of the packaging sheet is 20 gsm or more. The absorbent article according to any one of claims 1 to 11, wherein the acid is citric acid.

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