JP2007244442A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article improved in the absorption speed of excretion and which is improved in permeation and absorption of a highly viscous liquid. <P>SOLUTION: The absorbent article includes longitudinal composite materials 12 and 15 which contain two or more kinds of resins A and B which have different degrees of water absorbing and swelling property and in which the respective resins A and B are arranged so as to extend in a longitudinal direction. It is desirable that the composite materials 12 and 15 can be crimped two-dimensionally or three-dimensionally by absorbing and swelling of water. It is desirable that the composite materials 12 and 15 are included in an absorption core 16 or a covering sheet 17 covering it. It is desirable that the composite materials 12 and 15 are included in a surface sheet 18 or a sub-layer sheet 19 arranged on the lower side of it. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to various absorbent articles including disposable diapers and sanitary napkins.

  It is known to use a polyalkylene oxide polymer as a constituent material of an absorbent article. For example, an absorbent article is proposed in which a polyethylene oxide polymer having a number average molecular weight of 1,000 to 100,000 is held between a liquid permeable sheet and a liquid impermeable sheet in the absorbent article ( Patent Document 1).

  In this absorbent article, the polyethylene oxide polymer carried on the mesh sheet is held between the liquid permeable sheet and the absorbent body. According to this absorbent article, when the excreted loose stool comes into contact with the polyethylene oxide polymer, the polyethylene oxide polymer is dissolved by the water in the loose stool and dispersed in the loose stool. And, since the water is separated from the loose stool by the protein coagulation action of the dispersed polyethylene oxide polymer, and the separated water is quickly absorbed by the water absorbent resin, it is said that the skin of the wearer is kept dry. .

  However, since soft stool is highly viscous, it tends to stay on the surface sheet of the absorbent article, and it takes time for the stool to reach the site where the polyethylene oxide polymer is disposed after it is excreted. Accordingly, soft stools adhere to the wearer's skin during that time, and skin irritation tends to occur. In addition, in order for the polyethylene oxide polymer to be sufficiently dispersed in the stool, it is necessary that the polyethylene oxide polymer has a high solubility and a large diffusion coefficient. Even if the molecular weight (degree of polymerization) of the polymer is within the above range, it is considered to be limited to a smaller one. For this reason, it is not always preferable to use a polyethylene oxide polymer for the purpose.

JP2004-222939

  Therefore, the objective of this invention is providing the absorbent article which can eliminate the fault which the prior art mentioned above has.

  The present invention provides an absorbent article comprising a longitudinal composite material comprising two or more resins having different degrees of water-absorbing swellability, each resin being arranged to extend in the longitudinal direction. The goal has been achieved.

  According to the absorbent article of the present invention, the absorption rate of excreta is improved, and skin irritation or the like hardly occurs. In particular, according to the absorbent article of the present invention, the absorption rate of excrement is difficult to decrease even under the condition where the wearer's body pressure is applied. In addition, the permeation and absorption of high-viscosity liquids including soft stool is improved.

  Hereinafter, the present invention will be described based on preferred embodiments thereof. The absorbent article of the present invention is mainly used for absorbing and holding excretory body fluids such as urine and menstrual blood. The absorbent article of the present invention includes, for example, disposable diapers, sanitary napkins, incontinence pads, etc., but is not limited thereto, and widely includes articles used for absorbing liquid discharged from the human body. .

  The absorbent article of the present invention typically includes a top sheet, a back sheet, and a liquid-retaining absorbent body disposed between both sheets. As the top sheet and the back sheet, materials usually used in the technical field can be used without particular limitation. For example, as the surface sheet, liquid permeable sheets such as various nonwoven fabrics and perforated films subjected to a hydrophilic treatment can be used. As the back sheet, a liquid-permeable or water-repellent sheet such as a thermoplastic resin film or a laminate of the film and a nonwoven fabric can be used. The back sheet may have water vapor permeability. The absorbent article may further include various members according to specific uses of the absorbent article. Such members are known to those skilled in the art. For example, when applying an absorbent article to a disposable diaper or a sanitary napkin, a pair or two or more pairs of three-dimensional guards can be disposed on the left and right sides of the topsheet.

  1 (a) and 1 (b) schematically show the structure of an absorbent body according to an embodiment of the absorbent article of the present invention. FIG. 1A shows an absorber in a state before liquid absorption, and FIG. 1B shows an absorber in a state after liquid absorption. The absorbent body of the absorbent article shown in FIG. 1 is particularly characterized by the fact that the absorption rate of excrement does not decrease even under the condition where the wearer's body pressure is applied. The absorbent body 10 having such characteristics has an absorbent core 16 in which particles 11 of a superabsorbent polymer are mixed and dispersed in a long fiber web (hereinafter referred to as a web) 12, and a liquid-permeable covering sheet 17. It is constituted by being covered with. In the figure, the covering sheet 17 is shown as covering only the upper and lower surfaces of the absorbent core 16, but actually, it covers both the left and right side surfaces in addition to the upper and lower surfaces of the absorbent core 16.

  The long fiber is preferably hydrophilic. What is used in the present invention as a long fiber having hydrophilicity is a long fiber that is inherently hydrophilic, and inherently has no hydrophilicity, but is hydrophilic by being subjected to a hydrophilic treatment. Both of the long fibers to which is given are included. As will be described later, the long fiber used in the present embodiment is a composite material, and it is preferable that a part of the composite material inherently has hydrophilicity.

  The fiber diameter of the long fiber is related to the supportability of the superabsorbent polymer. Satisfactory supportability can be obtained by using long fibers of 1.0 to 7.8 dtex, particularly 1.7 to 5.6 dtex, provided that the basis weight of the web is the same. In the present invention, the long fiber means a fiber having a fiber length of preferably 70 mm or more, more preferably 80 mm or more, and even more preferably 100 mm or more when the fiber length is measured by the average fiber length measurement method (Method C) of JIS L1015. Say. However, when the total length of the web to be measured is less than 100 mm, preferably 50% or more, more preferably 70% or more, more preferably 80% or more of the fibers in the web extend over the entire length of the web. In this case, it is assumed that the fibers of the web are long fibers. The long fibers used in the present invention are generally called continuous filaments. A bundle of continuous filaments is generally called a tow. Therefore, the long fiber in the present invention is a concept including a continuous filament. The web in which the long fibers are oriented is a concept including a bundle of long fibers (so-called tow) as a raw material for forming the web and a tow layer of continuous filaments.

  Moreover, the fiber in which a part of the long fiber is cut and the fiber length is less than the above value (cut fiber) may be mixed in the absorbent body. In many cases, the cut fibers are produced in the manufacturing process.

  The long fibers used in this embodiment are made of a composite material. This composite material includes two or more resins having different degrees of swelling due to water absorption, and has a longitudinal shape in which each resin is arranged to extend in the longitudinal direction. The longitudinal shape has a width and a length, and has a shape that is sufficiently large compared to the width, for example, a shape whose length is 10 times or more of the width. An example of the longitudinal shape is a fibrous shape used in the present embodiment. Other examples include a tape-like or film-like shape having a narrow width (for example, a width of about 0.5 to 3.0 mm).

  FIG. 2 schematically shows a cross-sectional structure of long fibers made of the composite material. In Fig.2 (a), a long fiber consists of a side-by-side type composite fiber which consists of two types of resin A and B which are mutually different. In FIG.2 (b), a long fiber consists of an eccentric core-sheath-type composite fiber which consists of two types of resin A and B which are mutually different. 2A and 2B, the resins A and B are arranged so as to extend in the longitudinal direction of the fiber. “Extending in the longitudinal direction” is meant to include both the case of extending continuously and the case of extending discontinuously. 2 (a) and 2 (b), the cross section of the fiber is circular. However, the cross section of the fiber is not limited to a circular shape, and various shapes such as a polygon such as a triangle or a quadrangle, and a deformed shape such as a star. A fiber having a cross section of can be used.

  In FIGS. 2A and 2B, resins A and B having different water absorption swelling properties are used. The resins having different degrees of water swellability used in the present invention include both synthetic resins that swell by absorbing water and synthetic resins that do not substantially absorb water and consequently do not swell. Examples of the combination of the resins A and B include, for example, (a) a combination in which the resin A is a resin that swells due to water absorption, and the resin B does not substantially absorb water and as a result does not substantially swell as a result. However, a combination in which the degree of water swellability is a relatively large resin and the resin B is a resin having a relatively small degree of water swellability. Of these (A) and (B), the combination of (A) is more preferable. This is because the combination of (A) further deforms and crimps the fibers more three-dimensionally and improves the supportability and cushioning properties of the superabsorbent polymer.

  It is more preferable that the long fiber made of the composite material is crimped two-dimensionally or three-dimensionally from the beginning. This is because long fibers are enhanced in two-dimensional or three-dimensional crimp by absorbing water.

  In the case of (a) above, as the resin A that swells by water absorption, for example, a polyalkylene oxide water-absorbing swelling resin can be suitably used. This is because this resin has thermoplasticity in addition to its water absorption swelling ability, and therefore is easy to mold. On the other hand, as the resin B that does not substantially absorb water and consequently does not swell, conventionally known synthetic resins, for example, polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide 6 and polyamide 6 , 6 and the like, and vinyl resins such as polyvinyl chloride.

  In the case of the above (b), as the resins A and B, two kinds of polyalkylene oxide water-absorbing swelling resins in which the synthesis conditions are adjusted to make the degree of swelling different from each other can be suitably used.

  Examples of the polyalkylene oxide water-absorbing and swelling resin, which is a synthetic resin that absorbs water and swells, include homopolymers of alkylene oxides such as ethylene oxide, and copolymers of alkylene oxides such as ethylene oxide and monomers copolymerizable therewith. A polymer etc. are mentioned. When ethylene oxide is used as the alkylene oxide, for example, propylene oxide or butylene oxide can be used as a monomer copolymerizable therewith.

  As the polyalkylene oxide water-absorbing swelling resin, it is particularly preferable to use a polyethylene oxide water-absorbing swelling resin. Specific examples of the polyethylene oxide water-absorbing swelling resin include polyethylene glycol, ethylene oxide / propylene oxide copolymer, polyethylene glycol mono 4-octylphenyl ether, polyethylene glycol diacrylate, and the like. Of these, polyethylene glycol and ethylene oxide / propylene oxide copolymer are preferably used from the viewpoint of safety and economy.

  When an ethylene oxide / propylene oxide copolymer is used as the polyalkylene oxide water-absorbing swelling resin, the content of ethylene oxide in the copolymer is 30% by weight or more and 100% by weight from the viewpoint of developing sufficient water-absorbing / swelling ability. %, In particular 60% by weight or more and less than 100% by weight.

  The number average molecular weight of the polyalkylene oxide-based water-absorbing swelling resin is preferably 1000 or more, particularly 2000 or more from the viewpoint of preventing the resin from being dissolved by water absorption. Further, the upper limit of the number average molecular weight is 100,000 or less, particularly 50000 or less, especially 20000 or less. The polyalkylene oxide-based water-absorbing swelling resin is preferably crosslinked with a polyvalent metal ion such as titanium or iron or a chelating agent containing these metal ions.

  A commercially available product can also be used as the polyalkylene oxide water-absorbing swelling resin. Examples of such commercially available products include Aqua Coke (registered trademark) manufactured by Sumitomo Seika Co., Ltd.

  The long fibers made of the composite material described above differ in the degree of swelling due to water absorption of the resin constituting the long fiber. As a result, when the long fibers come into contact with excrement such as urine and menstrual blood, resins having different degrees of swelling swell according to the respective degrees, and thereby the long fibers are deformed and shown in FIG. In this way, the coil is three-dimensionally crimped. By this crimping, a space 13 is formed in the absorber 10. Due to the formation of the space 13, the absorption speed of the absorbent body 10 is improved. Moreover, even if the wearer's body pressure is applied to the absorbent body 10 and the thickness thereof is reduced, a certain amount of the space 13 remains, and therefore the excretion absorption rate is difficult to decrease. Furthermore, even if highly viscous excrement such as loose stool is excreted, the permeation and absorption through the space 13 is smoothly performed, so that it is difficult to stay on the top sheet. As a result, skin irritation and the like are less likely to occur.

  As described above, in the present embodiment, the space 13 is formed in the absorber 10 after the absorber 10 absorbs liquid. This is particularly advantageous in the case of a thin absorbent body, for example, an absorbent body having a thickness of 1 to 5 mm, particularly 1 to 3 mm, which is an absorbent body in which it is difficult to form a space in a normal manufacturing method.

The above-mentioned composite material crimped by water absorption has a crimp ratio (JIS L0208) of 10 to 90%, particularly 10 to 60%, especially 20 to 50%. From the point that can be formed. The crimp rate is defined as a percentage of the difference between the length A when the long fiber is stretched and the length B of the original long fiber with respect to the length A when stretched, and is calculated from the following equation: .
Crimp rate = (A−B) / A × 100 (%)
Here, the crimping rate includes the two-dimensional or three-dimensional crimp when the composite material is previously provided.

  In the present embodiment, it is not necessary that all the long fibers are composed of the composite material. For example, a predetermined amount of normal long fibers such as acetate and rayon may be blended. These long fibers may be crimped two-dimensionally or three-dimensionally from the beginning.

The basis weight of the absorbent body 10 in this embodiment, the absorbent article comprising the absorbent body 10 case of infant diapers, 50~600g / m ^2, it is preferred that particularly 150~500g / m ^2. In this case, the basis weight of the long fiber web in the absorbent body 10 is preferably 10 to 200 g / m ² , particularly preferably ²⁰ to 100 g / m ² . On the other hand, the basis weight of the superabsorbent polymer in the absorbent body 10 is preferably 50 to 400 g / m ² , particularly preferably 100 to 300 g / m ² .

  3 (a) and 3 (b) schematically show the structure of the absorbent body in another embodiment of the absorbent article of the present invention. FIG. 3A shows an absorber in a state before liquid absorption, and FIG. 3B shows an absorber in a state after liquid absorption. In this embodiment, the absorbent body 10 is configured by coating a liquid-permeable covering sheet 17 with an absorbent core 16 formed by dispersing and mixing superabsorbent polymer particles 11, fluff pulp 14 and short fibers 15. ing. 3A and 3B, the description regarding FIGS. 1A and 1B is appropriately applied to points that are not particularly described.

  The short fiber 15 used in the present embodiment is made of a composite material containing two or more kinds of resins having different degrees of water absorption swelling. As such a composite material, the same composite material as that constituting the long fiber used in the embodiment shown in FIGS. 1A and 1B can be used.

  Also in this embodiment, as shown in FIGS. 1A and 1B, when excrement is absorbed by the absorbent body 10, the short fibers 15 are deformed and shown in FIG. 3B. It is three-dimensionally deformed into a coil shape. By this crimping, a space 13 is formed in the absorber 10. As a result, also in this embodiment, the same effect as the embodiment shown in FIGS.

  The short fiber 15 made of the composite material used in the present embodiment is preferably 10 to 30 mm in length because it can be uniformly dispersed with the fluff pulp 14 and the superabsorbent polymer 11. The thickness of the short fiber 15 can be the same as the thickness of the long fiber used in the embodiment shown in FIGS. Moreover, the ratio of the fluff pulp 14 and the short fiber 15 which are fiber components contained in the absorbent body 10 is the former: the latter = 99.9: 0.1-50: 50, particularly 99.7: 0. It is preferable that it is 3-70: 30, especially 99: 1.0-80: 20.

The basis weight of the absorbent body 10 in the present embodiment is preferably 80 to 800 g / m ² , particularly preferably 100 to 700 g / m ² . The total basis weight of the fluff pulp 14 and the short fibers 15 which are fiber components in the absorbent body 10 is preferably 30 to 500 g / m ² , particularly 50 to 300 g / m ² . On the other hand, the basis weight of the superabsorbent polymer in the absorbent body 10 is preferably 30 to 500 g / m ² , particularly preferably 70 to 350 g / m ² .

  In the embodiment shown in FIGS. 1 (a) and 1 (b) and FIGS. 3 (a) and 3 (b), the composite material is contained in the absorbent core 16 of the absorbent body 10. Alternatively, or in addition thereto, the composite material may be contained in the covering sheet 17 that covers the absorbent core 16. The covering sheet 17 is composed of a liquid-permeable sheet such as paper manufactured by a wet method or a dry method, or a non-woven fabric. Accordingly, when the composite material is contained in the covering sheet 17, the composite material having, for example, the shape of short fibers may be contained in the raw material when the covering sheet 17 is manufactured.

  The inclusion of the composite material in the covering sheet 17 covering the absorbent core 16 means that when the absorbent body 10 absorbs excrement, a space is formed in the covering sheet 17 and the covering sheet 17 becomes bulky. It is advantageous from the point that the excretion passage is improved.

  The covering sheet 17 often contains various functional particles including deodorizers such as activated carbon and zeolite. When such functional particles are included in the covering sheet 17, the above composite is used. Use of a material in combination is preferable because the supportability of the functional particles is improved. The covering sheet 17 containing the functional particles and the composite material can be preferably manufactured as follows. Using the slurry containing the composite material as a papermaking raw material, wet papermaking is performed to produce a wet papermaking paper. In the papermaking paper, the composite material absorbs water and is thus crimped into a coil shape. Under this condition, functional particles are dispersed on the paper. The functional particles enter and are held in the space formed by the crimped composite material. Next, the paper-making paper in a wet state is dried to obtain the covering sheet 17. Papermaking shrinks by drying. By this contraction, the functional particles are more firmly held in the covering sheet 17. Adopting such a production method improves the supportability of the functional particles.

  FIG. 4 shows another embodiment of the present invention. The absorbent article of the embodiment shown in the figure has a liquid-permeable sublayer sheet 19 disposed between the absorbent body 10 and the top sheet 18. Reference numeral 20 denotes a liquid-impermeable or water-repellent back sheet. The sub-layer sheet 19 is used for the purpose of smoothly passing excrement from the top sheet 18 to the absorber 10 and for preventing the excrement absorbed by the absorber 10 from returning.

  In the absorbent article of this embodiment, the composite material is contained in the sublayer sheet 19 and / or the surface sheet 18. Since the sublayer sheet 19 and the surface sheet 18 are generally composed of a nonwoven fabric, in order to contain these composite materials in these sheets, for example, the raw materials used in the production of these sheets have a short fiber shape. What is necessary is just to contain the said composite material. The inclusion of the composite material in the sub-layer sheet 19 and / or the surface sheet 18 means that when the excrement is excreted, a space is formed in the sub-layer sheet 19 and / or the surface sheet 18 so that the sub-layer This is advantageous in that the sheet 19 and / or the surface sheet 18 becomes bulky and the passage of excrement is improved.

The superabsorbent polymer used in each of the above-described embodiments has a water absorption of 30 g / g or more, particularly 30 to 50 g / g, based on the centrifugal dehydration method. It is preferable from the point which prevents that the gel feeling after liquid absorption falls. The amount of absorption of the superabsorbent polymer by centrifugal dehydration is measured as follows. That is, 1 g of superabsorbent polymer was swollen with 150 ml of physiological saline for 30 minutes, then placed in a 250 mesh nylon mesh bag, dehydrated with a centrifuge at 143 G (800 rpm) for 10 minutes, and the total weight after dehydration was determined. taking measurement. Next, the amount of water absorption (g / g) by centrifugal dehydration is calculated according to the following formula.
Water absorption by centrifugal dehydration method = (total weight after dehydration−weight of nylon mesh bag−weight of highly absorbent polymer when dried−weight of nylon mesh bag liquid remaining) / weight of highly absorbent polymer when dried

  As the superabsorbent polymer, it is more preferable to use a superabsorbent polymer having high liquid permeability under load. In particular, from the viewpoint of effectively preventing gel blocking of the superabsorbent polymer, the superabsorbent polymer preferably has a flow rate value of 30 to 300 ml / min, more preferably 32 to 200 ml / min, still more preferably. Is 35 to 100 ml / min. When the value of the liquid flow rate is less than 30 ml / min, the superabsorbent polymers saturated and swollen by the liquid absorption adhere to each other under load, and the passage of the liquid is hindered, so that gel blocking easily occurs. The larger the value of the flow rate, the better from the viewpoint of preventing the occurrence of gel blocking. However, if the value of the flow rate is as high as about 300 ml / min, the occurrence of gel blocking is almost certainly prevented. When the liquid flow rate exceeds 300 ml / min, the fluidity of the liquid in the absorber is too high, especially when a large amount of excreta is excreted at once, or in older infants or adults. When the excretion rate is fast as described above, the liquid may not be sufficiently fixed when the absorber is further thinned, which may cause leakage. In general, increasing the liquid flow rate increases the degree of crosslinking of the superabsorbent polymer, lowering the absorption capacity per unit weight of the superabsorbent polymer, and a large amount of superabsorbent polymer must be used. I must. From these viewpoints, the upper limit value of the flow rate is determined.

  The superabsorbent polymer that can be used in each of the above-described embodiments is not particularly limited as long as it satisfies the above-mentioned characteristics. Specifically, for example, sodium polyacrylate and (acrylic acid-vinyl alcohol) Examples thereof include a polymer, a crosslinked polyacrylic acid soda, a (starch-acrylic acid) graft polymer, a (isobutylene-maleic anhydride) copolymer and a saponified product thereof, potassium polyacrylate, and cesium polyacrylate. In order to satisfy the above characteristics, for example, a crosslink density gradient may be provided on the surface of the superabsorbent polymer particles. Alternatively, the superabsorbent polymer particles may be non-spherical amorphous particles. Specifically, the method described in JP-A-7-18495, column 7 line 28 to column 9 line 6 can be used.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the above-described embodiment, the embodiment in which the composite material is composed of two types of resins has been mainly described. A material may be used.

  In the embodiment, the composite material is three-dimensionally crimped by water absorption. However, the deformation of the composite material is not limited to the coiled three-dimensional crimp, and may be a two-dimensional crimp such as bending. Good. Further, any deformation other than crimping may be used as long as the space is formed.

  Further, the above embodiments can be combined with each other. For example, the absorbent core 16 and the covering sheet 17 can contain the composite material, and the surface sheet 18 and the sublayer sheet 19 can also contain the composite material.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.

[Example 1]
Aqua coke (registered trademark), which is a polyalkylene oxide water-absorbing swelling resin manufactured by Sumitomo Seika, was dissolved by heating, and the resin was embedded in a half-moon shaped mold. Similarly, low density polyethylene was embedded in a half-moon shaped mold. Both were combined at the center to obtain a side-by-side composite. This composite was inserted into a barrel of a capillograph, and the filament extruded from the hole of the die was stretched and adjusted to become a long fiber having a predetermined thickness. This polyalkylene oxide water-absorbing swelling resin was obtained by crosslinking a polyethylene oxide water-absorbing swelling resin with a chelating agent containing titanium, and the number average molecular weight was 5,500.

The obtained long fiber was passed between the uneven rolls to give a two-dimensional crimp. A plurality of long fibers were arranged to obtain a web having a basis weight of 30 g / m ² . A superabsorbent polymer was sprayed on the web at a basis weight of 100 g / m ² . The web was wrapped with a hydrophilic SMS nonwoven fabric coated with an adhesive on the inside, and the whole was compressed with a rubber roll to obtain an absorbent body. The hydrophilized SMS nonwoven fabric is a spunbond-meltblown-spunbond nonwoven fabric treated with a surfactant (ethylene oxide adduct of sorbitan ester of C18 fatty acid of HLB12). This hydrophilic SMS nonwoven fabric was subjected to a hole opening treatment with a hot pin having a diameter of 5 mm. A plurality of pins are arranged in a staggered manner with a vertex interval of 10 mm in the width direction and 10 mm in the longitudinal direction. As shown in FIG. 5, the opening was formed in a region that is 100 to 200 mm from the ventral end in the longitudinal direction and covers the entire width direction when the absorber is viewed in plan.

A liquid-permeable surface material and a liquid-impermeable back material were stacked on the obtained absorbent body, and a disposable diaper was obtained according to a normal disposable diaper manufacturing method. As the surface material and the back surface material, those used in ordinary disposable diapers were used. Specifically, the surface material is composed of a core-sheath type composite fiber (thickness: 2.1 dtex, surface treatment with a surfactant) having a core of polypropylene and a sheath of linear low density polyethylene, and has a basis weight of 25 g / m. An air-through nonwoven fabric having a liquid permeability of ² was used. The surface material was subjected to an opening treatment using a heated metal pin having a diameter of 5 mm. The rear material, the porous film having a basis weight of 20 g / m ^2, was used as the composite by bonding a polypropylene spunbond nonwoven fabric having a basis weight of 20 g / m ² hot melt 1.5 g / m ^2. This porous film was obtained by uniformly blending 100 parts by weight of a linear low-density polyethylene resin having a density of 0.925 g / cm ³ with 150 parts by weight of calcium carbonate and an ester compound as a third component. It was obtained by uniaxially stretching twice in the direction.

  An air-through nonwoven fabric having liquid permeability was laminated on the back material side of the surface material. This air-through non-woven fabric was composed of a core-sheath type composite fiber (thickness: 5.6 dtex, surface treatment with a surfactant) having a core made of polypropylene and a sheath made of linear low density polyethylene. This air-through nonwoven fabric is not subjected to hole opening treatment.

[Example 2]
Aqua Coke (registered trademark) manufactured by Sumitomo Seika Co., Ltd. was dissolved by heating to obtain a film having a thickness of 20 microns. As shown in FIGS. 6A and 6B, a strip 31 made of low density polyethylene and having a width of 10 mm was laminated on the film 30 so that the distance between the strips 31 was 5 mm. The obtained two-layer film was cut with a width of 1 mm in a direction perpendicular to the longitudinal direction of the strip 31 to obtain an elongated piece 32. As shown in FIG. 6C, the small piece 32 is provided with an aqua coke continuous layer 33 on one side and a non-continuous layer 34 of a low density polyethylene layer on the other side. 10% by weight of the obtained small piece and 90% by weight of softwood pulp NBKP were mixed, and further, a paper strength enhancer or the like usually used was mixed, and papermaking and drying were performed to obtain tissue paper. The absorbent body obtained in Example 1 was wrapped with the obtained tissue paper. Thereafter, the same operation as in Example 1 was performed to obtain a disposable diaper.

[Comparative Example 1]
100 parts by weight of the opened fluff pulp and 100 parts by weight of the superabsorbent polymer were uniformly mixed in an air stream to obtain a mixture having a total basis weight of 520 g / m ² . The basis weights of the fluff pulp and the superabsorbent polymer were 260 g / m ² , respectively. The obtained mixture was wrapped with a non-woven SMS nonwoven fabric similar to that used in Example 1 to obtain an absorbent body. Thereafter, the same operation as in Example 1 was performed to obtain a disposable diaper.

[Comparative Example 2]
Instead of the long fiber used in Example 1, a completely saponified polyvinyl alcohol (PVA) long fiber (degree of polymerization 2400, completely saponified product, 1.5 denier, shrinkage in water at 20 ° C. is 30%) is used. A disposable diaper was obtained by carrying out the same operations as in Example 1 except that.

[Evaluation]
The absorbent body was taken out from the obtained disposable diaper, and the absorbent performance of the absorbent body was evaluated by the following method. The results are shown in Table 1.

[Absorbent absorption performance evaluation method]
A viscous liquid prepared by appropriately adding water to a laundering paste (PVA) to adjust the viscosity to 30 cSt was used as a test liquid. The viscosity was measured at room temperature using a B-type viscometer. The absorber was cut into a 50 mm square, and this was sandwiched from above and below by a glass tube having an inner diameter of 35 mm (an edge having a diameter of 50 mm formed on one side of the tube). 20 ml of the test solution was injected at once from the top of the tube, and the time until the solution disappeared from the upper surface of the absorber was measured. At this time, a part of the liquid passes through the absorber and leaks downward. And the absorption performance was evaluated according to the following judgment criteria.
○: The entire amount of the test solution is absorbed by the absorber within 1 minute.
Δ: The total amount of the test solution is absorbed by the absorber within 3 minutes.
X: The whole amount of the test solution is not absorbed even after 10 minutes or more

  As is clear from the results shown in Table 1, it can be seen that the absorbent bodies of the respective examples are excellent in the absorbability of the highly viscous liquid. On the other hand, the absorbent body of Comparative Example 1 has too much clogged fluff pulp in Comparative Example 1, and the absorbent body of Comparative Example 2 has partially clogged portions due to the shrinkage of PVA fibers. As a result, the absorbency of the highly viscous liquid is inferior.

It is a schematic diagram which shows the structure of the absorber in one Embodiment of the absorbent article of this invention. It is a schematic diagram which shows the cross-section of the fiber used as a composite material. It is a schematic diagram which shows the structure of the absorber in other embodiment of the absorbent article of this invention. It is a schematic diagram which shows the cross-section of other embodiment of the absorbent article of this invention. FIG. 3 is a schematic diagram illustrating a region where an opening process has been performed in the absorbent body manufactured in Example 1. 6 is a schematic diagram showing a composite material manufactured in Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Absorber 11 Superabsorbent polymer particle 12 Long fiber web 13 Space 14 Fluff pulp 15 Short fiber 16 Absorbent core 17 Cover sheet 18 Top sheet 19 Sublayer sheet 20 Back sheet

Claims (6)

  An absorbent article comprising a composite material having a longitudinal shape, comprising two or more resins having different degrees of water absorption swellability, each resin being arranged so as to extend in the longitudinal direction.   The absorbent article according to claim 1, wherein the composite material is crimpable by water absorption swelling.   The absorbent article according to claim 1 or 2, further comprising an absorbent body including an absorbent core and a liquid-permeable covering sheet that covers the absorbent core, wherein the composite material is included in the absorbent core or the covering sheet.   The absorbent article according to claim 1, further comprising a liquid-permeable sublayer sheet disposed between the absorber and the surface sheet, wherein the composite material is included in the surface sheet or the sublayer sheet. .   The absorbent article according to any one of claims 1 to 4, wherein the composite material is in the form of a fiber, or in the form of a narrow tape or a film. The absorbent article according to any one of claims 1 to 5, wherein the composite material includes a polyalkylene oxide water-absorbing swelling resin as one of the resins.

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