Absorber and absorbent article

Abstract

To provide an absorber having sufficient absorption performance while adopting a natural product-derived raw material as a main raw material of a superabsorbent polymer, and an absorbent article including the absorber, and absorbent article including the absorber.SOLUTION: An absorber of a two-layer structure comprising a first absorber to be disposed on a skin side surface of a wearer and a second absorber to be disposed on a non-skin side surface of the wearer, the absorber is characterized in that the first absorber is comprised of a non-natural product-derived superabsorbent polymer and fluff pulp, and has a slit along a longitudinal direction, and the second absorber is comprised of a natural product-derived superabsorbent polymer and a base nonwoven fabric.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an absorbent body and an absorbent article including the absorbent body. [Background technology]

[0002] Research is underway to use naturally derived polysaccharides in superabsorbent polymers (SAPs) as sustainable raw materials for absorbent products such as disposable diapers, and the use of starch as one of these is being considered.

[0003] For example, Patent Document 1 discloses a method for producing a water-absorbent resin composition at low cost, with high productivity and good operability, using a sustainable raw material in which starch particles are added to conventionally used polyacrylic acid (salt)-based water-absorbent resin particles. However, as described in the same document, there is a problem that as the content of starch increases, CRC (absorbency without load) and AAP (absorbency against load) decrease.

[0004] Furthermore, for example, Patent Document 2 discloses an absorbent article that uses a granular water-absorbing agent made of a cross-linked naturally-derived polymer and trehalose as a constituent element of the absorbent body, and that has improved initial response of water absorption and re-swelling, i.e., water absorption rate and instantaneous water absorption capacity. However, biodegradable water-absorbing agents still have the problem of being inferior in water absorption rate and instantaneous water absorption capacity compared to conventional polyacrylic acid-based absorbents.

[0005] As such, SAPs made from natural materials have inferior absorption performance compared to SAPs made from sodium polyacrylate, which have been used conventionally. Therefore, the development of absorbent materials with sufficient absorption performance and absorbent articles using such absorbent materials has been a challenge.

[0006] Furthermore, absorbent articles such as disposable diapers are made by bonding various components, such as nonwoven fabric, SAP, and elastic thread, with hot melt adhesive, and developing a method for separating these components has been a challenge in order to efficiently recycle used absorbent articles. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-185314 [Patent Document 2] Japanese Patent Application Publication No. 2017-071756 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide an absorbent body and an absorbent article equipped with the absorbent body that have sufficient absorption performance while using natural-derived raw materials as the main raw material of the superabsorbent polymer (hereinafter also referred to as "SAP"). [Means for solving the problem]

[0009] The inventors have conducted extensive research and have found that the above-mentioned problems can be solved by specifying the SAP, substrate, and shape used in the first absorbent body, and the SAP and substrate used in the second absorbent body, in a two-layer absorbent body consisting of a first absorbent body placed on the skin-side surface of the wearer and a second absorbent body placed on the non-skin-side surface of the wearer, and have thus completed the present invention.

[0010] [1] The absorbent body has a two-layer structure consisting of a first absorbent body that is placed on the side facing the wearer's skin and a second absorbent body that is placed on the side facing away from the wearer's skin, wherein the first absorbent body is made of a non-naturally derived superabsorbent polymer and fluff pulp and has a slit along the longitudinal direction, and the second absorbent body is made of a naturally derived superabsorbent polymer and a base nonwoven fabric.

[0011] [2] [1] The absorbent body described in [1] is characterized in that the non-naturally derived superabsorbent polymer is a polyacrylic acid-based superabsorbent polymer, and the naturally derived superabsorbent polymer is a starch-based superabsorbent polymer.

[0012] [3] [1] or [2], the absorbent body according to [1] or [2], wherein the basis weight of the non-naturally derived superabsorbent polymer is 50 g / m 2 More than 400g / m 2 It is characterized by the following:

[0013] [4] [1] or [2], wherein the basis weight of the fluff pulp is 100 g / m 2 More than 800g / m 2 It is characterized by the following:

[0014] [5] The absorbent body according to [1] or [2] is characterized in that the slit has a width of 10% to 20% of the total width of the first absorbent body and a length of 10% to 100% of the total length of the first absorbent body.

[0015] [6] [1] or [2], the absorbent body according to [1] or [2], wherein the basis weight of the naturally derived superabsorbent polymer is 100 g / m 2 More than 1200g / m 2 It is characterized by the following:

[0016] [7] [1] or [2] is an absorbent body according to the present invention, characterized in that the first absorbent body and the second absorbent body are bonded with a structural hot melt, the naturally derived highly absorbent polymer is fixed to the base nonwoven fabric with a supporting hot melt, and the supporting hot melt adhesive has a softening point measured by the ring and ball method that is 10°C or more higher than that of the structural hot melt adhesive.

[0017] [8] [7] The absorbent body according to the present invention, wherein the amount of adhesive applied to the hot melt carrier is 15 g / m 2 More than 50g / m 2 It is characterized by the following:

[0018] [9] The absorbent article is characterized by comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and the absorbent body described in [1] or [2] placed between them. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide an absorbent core that uses natural-derived raw materials as the main raw materials for SAP, yet has sufficient absorption performance, and an absorbent article that includes the absorbent core.

[0020] Furthermore, it is possible to provide an absorbent core that is easily recyclable and an absorbent article that includes the absorbent core, while using both SAP made from natural materials and SAP made from non-natural materials. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a plan view showing an embodiment of an absorbent body and an absorbent article according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing a part of the cross section AA in FIG. [Figure 3] FIG. 1 is an explanatory diagram of a method for measuring absorption rate. DETAILED DESCRIPTION OF THE INVENTION

[0022] In this specification, "absorption performance" refers to the body fluid absorption rate, returnability after absorbing body fluid, and comfort when worn. "Wearing an absorbent article" refers to the state in which the absorbent article is worn on the body, regardless of whether body fluid has been absorbed or not. In absorbent articles, the "longitudinal direction" refers to the direction indicated by Y in the figure, which extends from the front to the back of the body via the wearer's crotch when the absorbent article is worn on the body. The "width direction" refers to the direction indicated by X in the figure, which is perpendicular to the longitudinal direction. The "thickness direction" refers to the direction indicated by Z in the figure, in which the various components are stacked. The "skin side" refers to the surface that contacts or faces the wearer's skin when the absorbent article is worn, and the "non-skin side" refers to the surface that contacts or faces the wearer's clothing when the absorbent article is worn. "Body fluid" refers to liquids excreted from the body to the outside, such as urine, blood, and water in loose stools.

[0023] <Absorbent bodies and absorbent articles> Hereinafter, the present embodiment will be described with reference to the drawings. Fig. 1 shows an absorbent body 3 according to a first embodiment and an absorbent article 1 using this absorbent body 3. Fig. 2 shows the structure of a cross section taken along line AA in Fig. 1. These drawings do not prescribe the shapes, dimensions, size relationships, etc. of the components in the absorbent body 3 and absorbent article 1 of the present embodiment.

[0024] The absorbent core 3 of this embodiment can be used as various absorbent articles 1 for both babies and adults, and representative examples include light incontinence pads, urine absorption pads, pants-type disposable diapers, tape-fastened disposable diapers, etc. Various types of disposable diapers may be combined as outer layers with the absorbent article 1 as inner layers. There are no particular limitations on either the length or width of the absorbent article 1, but they are, for example, in the range of 50 mm or more and 1000 mm or less. By adjusting the dimensions of the absorbent article 1 to fall within the above ranges, absorbent articles for various uses can be obtained.

[0025] As shown in Figure 2, the absorbent article 1 comprises a liquid-permeable top sheet 2 that is positioned relatively closer to the skin when the absorbent article 1 is worn, a liquid-impermeable back sheet 4 that is positioned opposite the top sheet 2 and relatively closer to the skin when the absorbent article 1 is worn, and an absorbent body 3 that is positioned between the top sheet 2 and the back sheet 4. The absorbent body 3 is sandwiched between the top sheet 2 and the back sheet 4, and body fluids such as urine are absorbed and retained in the absorbent body 3 through the top sheet 2. Leg gathers, waist gathers, side flaps, etc. can be provided as appropriate depending on the use and type of the absorbent article 1.

[0026] <Absorbent> 1 and 2, the absorbent body 3 of this embodiment has a two-layer structure consisting of a first absorbent body 31 placed on the wearer's skin side and a second absorbent body 32 placed on the wearer's non-skin side. The first absorbent body 31 and the second absorbent body 32 are preferably fixed together with a structural hot melt adhesive.

[0027] The planar shape of the absorbent body 3 is not particularly limited, and can be, for example, an hourglass shape, a substantially rectangular shape (rectangular shape), an I-shape, an oval shape, an ellipse shape, a rectangle with rounded corners, or the like. Furthermore, the longitudinal dimension (or maximum longitudinal dimension) and width dimension (or maximum width dimension) of the absorbent body 3 are not particularly limited, and can be selected appropriately depending on the use, form, etc. of the absorbent article 1. For example, the longitudinal dimension is in the range of 150 mm to 900 mm, and the width dimension of the absorbent body 3 is, for example, in the range of 50 mm to 400 mm.

[0028] <First absorbent body> The first absorbent body 31 is made of a non-naturally derived superabsorbent polymer (hereinafter also referred to as "first SAP") 311 and fluff pulp 312, and has slits 5 along the longitudinal direction.

[0029] (1st SAP) The absorbent component used in the first absorbent body 31 is a non-naturally derived superabsorbent polymer 311. If the first SAP 311 is made from a non-naturally derived material, it can absorb body fluids more quickly and thoroughly than SAPs made from natural materials.

[0030] The first SAP311 is not particularly limited as long as it can absorb body fluids and prevent backflow, and examples thereof include polyacrylates, polyaspartates, (acrylic acid-vinyl alcohol) copolymers, (isobutylene-maleic anhydride) copolymers, and saponified products thereof. Among these, from the viewpoint of absorption capacity per weight, polyacrylic acid-based highly absorbent polymers are preferred, specifically polyacrylates are preferred, and sodium polyacrylate is more preferred. SAPs can be used alone or in combination of two or more. The form of the first SAP311 is not particularly limited, but from the viewpoint of suppressing gel blocking and the like, particulate form is preferred, and particulate form with a median particle size is more preferred.

[0031] (Basis weight of 1st SAP) The basis weight of No. 1 SAP311 is 50 g / m 2 More than 400g / m 2 The basis weight of the first SAP311 is preferably 50 g / m or less. 2 If it is less than 400g / m, it will not be able to absorb enough body fluids. 2 If the absorbent body 3 exceeds this value, the absorbent body 3 will swell when absorbing body fluids, affecting the wearing comfort, and furthermore, fluid will return due to body pressure.

[0032] (Fluff pulp) The absorbent base material used in the first absorbent body 31 is fluff pulp 312. By using fluff pulp as the absorbent base material, bodily fluids excreted by the wearer can be absorbed quickly and sufficiently.

[0033] Examples of fluff pulp 312 include wood pulp, synthetic fiber, polymer fiber, non-wood pulp, etc., which have been defibrated into a cotton-like state. In this embodiment, other absorbent substrates can be used together with the fluff pulp. The other absorbent substrates are not particularly limited as long as they are used in absorbent articles such as sanitary napkins, diapers, and urine absorption pads, and examples thereof include cotton, rayon, acetate, tissue, absorbent paper, and hydrophilic nonwoven fabric.

[0034] (Fluff pulp basis weight) The basis weight of fluff pulp 312 is 100 g / m 2 More than 800g / m 2 The basis weight of the fluff pulp 312 is preferably 100 g / m 2 If the basis weight is less than 800 g / m, the amount of absorbed body fluid will be small, and the body fluid will not be sufficiently diffused into the second absorbent body 32. 2 If the thickness exceeds this value, it becomes difficult to stably manufacture the first absorbent body 31 during manufacturing, and the absorbent body 3 becomes excessively thick, affecting the wearing comfort.

[0035] (Shape of the first absorbent body) The first SAP 311 and fluff pulp 312 in the first absorbent body 31 may be in the form of a laminated mat formed by mixing and dispersing first SAP 311 particles in the fluff pulp 312, or may be an SAP sheet in which first SAP 311 particles are fixed between pieces of fluff pulp 312. Furthermore, to prevent particle leakage of the first SAP 311 and to stabilize the shape of the first absorbent body 31, the first absorbent body 31 may be wrapped in a carrier sheet. The substrate of the carrier sheet may be any hydrophilic material, such as tissue, absorbent paper, or a hydrophilic nonwoven fabric such as an air-laid nonwoven fabric. When multiple carrier sheets are used, the substrates of the multiple carrier sheets may be the same or different.

[0036] (1st SAP content ratio) In the first absorbent body 31, the ratio of the mass of the first SAP 311 to the mass of the fluff pulp 312 is preferably 40% or more and 120% or less, and more preferably 50% or more and 100% or less. This ratio is calculated by the following formula. Ratio = (mass of first SAP311) ÷ (mass of fluff pulp) × 100 (%)

[0037] (slit) The first absorbent body 31 has slits 5 extending along the longitudinal direction. By having the slits 5 extending along the longitudinal direction of the first absorbent body 31, bodily fluid absorbed by the first absorbent body 31 can be quickly diffused into the second absorbent body 32. At least one slit 5, and preferably two or more, is provided. Furthermore, the slits 5 preferably penetrate the first absorbent body 31 in the thickness direction.

[0038] The width of the slit 5 is preferably 10% to 20% of the overall width of the first absorbent body 31. The length of the slit 5 is preferably 10% to 100% of the overall length of the first absorbent body 31. If the width is less than 10% of the overall width or the length is less than 10% of the overall length, the bodily fluid absorbed by the first absorbent body 31 cannot be promptly diffused to the second absorbent body 32. If the width exceeds 20% of the overall width, the wearer is more likely to feel the second absorbent body 32 getting wet again.

[0039] <Second absorbent body> The second absorbent body 32 is composed of a naturally derived superabsorbent polymer (hereinafter also referred to as "second SAP") 321 and a base nonwoven fabric 322. The second SAP 321 is preferably fixed to the base nonwoven fabric 322 with a supporting hot melt .

[0040] The shape and dimensions of the second absorbent body 32 are based on the shape and dimensions of the absorbent body 3. The second absorbent body 32 may have dimensions in the longitudinal direction and / or width direction greater than those of the first absorbent body 31. For example, when the laminate of the first absorbent body 31 and the second absorbent body 32 is observed from above, the periphery of the second absorbent body 32, particularly the periphery in the longitudinal direction, may be made visible.

[0041] (2nd SAP) The absorbent component used in the second absorbent body 32 is a naturally derived superabsorbent polymer 321. By using an SAP made from natural materials in the second absorbent body 32 on the side opposite to the wearer's skin, an environmentally friendly absorbent body 3 can be achieved. Furthermore, by using it in combination with the first SAP 311 made from a non-natural material, high absorbency can be achieved.

[0042] The second SAP321 is not particularly limited as long as it is a naturally occurring raw material that can absorb body fluids, and examples thereof include starch, modified starch, amylose, modified amylose, chitosan, modified chitosan, chitin, modified chitin, gelatin, konjac, processed konjac, fenugreek gum, processed fenugreek gum, mesquite gum, processed mesquite gum, aloemannan, processed aloemannan, oxidized polysaccharides, sulfurized polysaccharides, cationic polysaccharides, etc. Among these, starch-based superabsorbent polymers are preferred from the viewpoint of body fluid absorbency.

[0043] (Basis weight of second SAP) The basis weight of No. 2 SAP321 is 100 g / m 2 More than 1200g / m 2 A basis weight of 100 g / m or less is preferred. 2 If the basis weight is less than 1200g / m, it will not be able to absorb body fluids sufficiently. 2 If the temperature exceeds this range, second SAP 321 may not be properly supported on base nonwoven fabric 322, and the base nonwoven fabric may swell excessively when absorbing body fluids, which may cause operational problems.

[0044] (Base nonwoven fabric) The absorbent base material used in the second absorbent body 32 is a base nonwoven fabric 322. Using the base nonwoven fabric 322 as the absorbent base material achieves a good balance between the supportability and absorption performance of the second SAP 321. Examples of the base nonwoven fabric 322 include nonwoven fabrics such as air-through nonwoven fabrics, point-bonded nonwoven fabrics, spunbonded nonwoven fabrics, and melt-blown nonwoven fabrics, as well as composite nonwoven fabrics such as spunbonded nonwoven fabric / melt-blown nonwoven fabrics and spunbonded nonwoven fabric / melt-blown nonwoven fabric / spunbonded nonwoven fabrics. Among these nonwoven fabrics, air-through nonwoven fabrics are preferred from the viewpoints of increasing bulk and improving water permeability.

[0045] (Basis weight of base nonwoven fabric) When an air-through nonwoven fabric is used as the base nonwoven fabric 322, the basis weight of the air-through nonwoven fabric is 20 g / m 2 More than 200g / m 2 Within this range, the transfer of body fluids to the raised surface and productivity are improved.

[0046] (Thickness of base nonwoven fabric) The thickness of the base nonwoven fabric 322 is preferably 0.3 mm or more and 11.0 mm or less, in which case a good balance between comfort and absorbency is achieved.

[0047] (Fiber thickness of base nonwoven fabric) The fiber thickness of base nonwoven fabric 322 is preferably 1.6 dtex to 14 dtex, inclusive. Within this range, base nonwoven fabric 322 can be easily raised, and second SAP 321 can be easily dispersed and supported among the fibers in the raised portion.

[0048] (Hot melt for support) There are no particular restrictions on the method for fixing second SAP 321 to base nonwoven fabric 322, but from the viewpoint of recycling, fixing is preferably done with a supporting hot melt 34. Examples of supporting hot melt 34 include synthetic rubber-based hot melt adhesives such as styrene-butadiene-styrene copolymers and styrene-isoprene-styrene copolymers, and olefin-based hot melt adhesives such as ethylene-vinyl acetate copolymers.

[0049] (Softening point of hot melt for support) The softening point of the supporting hot melt 34 can be any value between 100°C and 180°C, without any particular limitations. It is preferable to use a hot melt 34 that is at least 10°C higher than the softening point of the structural hot melt 33, which will be described later. The softening point of the hot melt refers to the boundary temperature range where the adhesive changes from solid to liquid when heated and melted, and can be measured by the ring and ball method based on JIS K-2351.

[0050] (Amount of hot melt applied for support) The amount of adhesive applied to the supporting hot melt 34 is 15 g / m 2 on the SAP-mounted surface of the base nonwoven fabric 322. 2 More than 50g / m 2 A coating amount of 15 g / m or less is preferred. 2 If the applied amount is less than 50 g / m, there is a risk that the second SAP321 may not be supported in an amount sufficient to absorb body fluids. 2 If the temperature exceeds this range, there is a risk that separation of the second SAP 321 will be hindered when the absorbent article 1 is recycled.

[0051] The hot melt carrier 34 can be applied by any known method, such as a curtain coating method or spiral method in which molten hot melt adhesive is applied from a nozzle in a non-contact manner, or a slot method in which it is applied in a contact manner.

[0052] <Absorbent> The first absorbent body 31 and the second absorbent body 32 are laminated to form the absorbent body 3 having a two-layer structure.

[0053] (Structural hot melt) The method for bonding the first absorbent body 31 and the second absorbent body 32 is not particularly limited, but from the perspective of recycling, bonding with a structural hot melt 33 is preferred. The structural hot melt 33 is also preferably used when bonding the absorbent body 3 to the top sheet 2 and the back sheet 4 described below. As with the supporting hot melt 34, examples of the structural hot melt 33 include synthetic rubber-based hot melt adhesives such as styrene-butadiene-styrene copolymers and styrene-isoprene-styrene copolymers, and olefin-based hot melt adhesives such as ethylene-vinyl acetate copolymers.

[0054] (Softening point of structural hot melt) The softening point of the structural hot melt 33 can be any value between 100°C and 180°C, without any particular limitations. It is preferable to use a hot melt 33 that is at least 10°C lower than the softening point of the aforementioned supporting hot melt 34. The softening point of the hot melt can be measured by the ring and ball method based on JIS K-2351.

[0055] The softening point of the supporting hot melt 34 is at least 10°C higher than that of the structural hot melt 33, which provides the following benefits during recycling: When recycling the absorbent 3, the absorbent 3 is crushed and then treated at the softening point of the structural hot melt 33, followed by centrifugation, which allows the first SAP 311 to be separated and recovered. The temperature is then raised and the absorbent 3 is treated at the softening point of the supporting hot melt 34, which allows the second SAP 321, derived from natural products, to be selectively extracted. This makes it easy to separate and recover the two types of SAP during recycling, resulting in an absorbent 3 that is easy to recycle.

[0056] Furthermore, the absorbent body 3 has a two-layer structure consisting of the first absorbent body 31 and the second absorbent body 32, which provides the following effects: Although naturally-derived SAP has inferior absorption performance compared to non-naturally-derived SAP, by using the base nonwoven fabric 322 (for example, an air-through nonwoven fabric) to form the second absorbent body 32 (SAP sheet), the content of naturally-derived SAP can be increased, thereby improving the amount of body fluid absorbed.

[0057] Furthermore, by disposing the second absorbent body 32 on the non-skin side, it is possible to prevent the wetness from returning due to body pressure.

[0058] Furthermore, with regard to the gel blocking phenomenon specific to SAP, body fluids migrate from the first absorbent body 31 to the second absorbent body 32, diffuse, and then migrate again to the first absorbent body 31 which has fluff pulp, so that the body fluids can be absorbed by the entire two-layer absorbent body 3, making it less likely that the absorption rate will decrease even with repeated excretion.

[0059] Furthermore, since the first absorbent body 31 is provided with the slits 5, bodily fluids can be quickly diffused and absorbed into the second absorbent body 32.

[0060] <Absorbent articles> 2, the absorbent article 1 of this embodiment has a liquid-permeable top sheet 2 placed on the wearer's skin side, an absorbent body 3 placed so that a first absorbent body 31 is adjacent to the top sheet 2, and a liquid-impermeable back sheet 4 placed on the non-skin side of the wearer. The top sheet 2 and absorbent body 3, and the absorbent body 3 and back sheet 4 are bonded together with, for example, a structural hot melt 33.

[0061] The following describes the top sheet 2 and the back sheet 4. These components may have a three-dimensional structure other than a sheet or plate shape.

[0062] (Top sheet) The top sheet 2 is a liquid-permeable sheet-like member that allows bodily fluids to pass quickly toward the absorbent body 3, and is disposed opposite the back sheet 4, sandwiching the absorbent body 3. Because the top sheet 2 may come into contact with the wearer's skin, a base material that is soft to the touch and does not irritate the skin is preferred.

[0063] Examples of the substrate include hydrophilic nonwoven fabrics, composite nonwoven fabrics which are laminates of the same or different types of hydrophilic nonwoven fabrics, apertured films such as apertured polyethylene films, foamed films such as urethane foam, etc. Hydrophilic nonwoven fabrics can be obtained by processing synthetic fibers made of synthetic resins such as polypropylene and polyethylene, regenerated fibers such as rayon, and natural fibers such as cotton using known methods such as the air-through method, thermal bond method, spunlace method, and spunbond method.

[0064] The surface of the top sheet 2 may be embossed or perforated to improve liquid permeability. Any known method can be used for embossing or perforating the top sheet 2 without limitation. Furthermore, to reduce irritation to the skin, the top sheet 2 may contain lotions, antioxidants, anti-inflammatory ingredients, pH adjusters, antibacterial agents, moisturizers, and the like.

[0065] The basis weight of the top sheet 2 is set to 15 g / m from the viewpoints of strength, processability, and liquid return. 2 More than 40g / m2 The following is preferable: The shape of the top sheet 2 is not particularly limited, and it may have any shape that covers the absorbent body 3 and is necessary to guide bodily fluids to the absorbent body 3 without leakage.

[0066] (back seat) The backsheet 4 may be formed using a liquid-impermeable substrate that prevents body fluids held by the absorber 3 from wetting clothing, and is formed from a material such as a resin film or a composite sheet formed by laminating a resin film and a nonwoven fabric. The nonwoven fabric used in the composite sheet may be made by any method, and examples thereof include spunbond nonwoven fabric, meltblown nonwoven fabric, composite nonwoven fabrics that are laminates of spunbond nonwoven fabric / meltblown nonwoven fabric, composite nonwoven fabrics that are laminates of spunbond nonwoven fabric / meltblown nonwoven fabric / spunbond nonwoven fabric, and composite materials thereof. Examples of resin films include polyester, polyvinyl alcohol, polyethylene, polypropylene, and composite films of polyethylene and polypropylene.

[0067] From the viewpoint of strength and processability, the basis weight of the back sheet 4 is, for example, 15 g / m 2 More than 40g / m 2 The range is as follows. In order to prevent stuffiness during wearing, it is preferable that the back sheet 4 is breathable. In order to make the back sheet 4 breathable, for example, a filler may be blended into the resin film of the base material, or the back sheet 4 may be embossed to form holes. An example of the filler is calcium carbonate, and the blending method may be any known method without any restrictions.

[0068] <Method for manufacturing absorbent articles> The absorbent article 1 can be manufactured by a known manufacturing method. For example, it can be manufactured by a manufacturing method including the steps of placing the absorbent body 3 between the top sheet 2 and the back sheet 4, and fixing the top sheet 2 and the back sheet 4 partially or entirely together using a hot melt adhesive, heat embossing, ultrasonic embossing, high-frequency embossing, or the like. When the absorbent article 1 is a urine absorption pad or a light incontinence pad, it can be individually packaged in a package and then folded lengthwise in thirds. Leg gathers, waist gathers, side flaps, and the like can be provided as needed.

[0069] Although the present invention has been described above using embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope of the invention described in the above embodiments, and it will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, it is apparent from the claims that forms incorporating such modifications and improvements can also be included within the technical scope of the present invention. [Example]

[0070] The embodiments of the present invention will be described more specifically below with reference to examples and comparative examples.

[0071] Example 1 (1) First, fluff pulp (basis weight 200 g / m) was placed in an area of ​​400 mm in length (longitudinal direction) and 200 mm in width (transverse direction). 2 ) 16g and sodium polyacrylate (basis weight 100g / m 2 8 g of SAP) is mixed, and a slit 5 having a length (longitudinal direction) of 200 mm and a width (transverse direction) of 30 mm is formed in the center to prepare the first absorbent body 31. The slit 5 penetrates in the thickness direction. (2) Next, an air-through nonwoven fabric (basis weight 20 g / m 2 A sheet of air-through nonwoven fabric (300 mm long, 200 mm wide) was prepared. One side of the surface was physically raised with a rotary saw blade, and a starch-based superabsorbent polymer (200 g / m2 basis weight) was inserted between the fibers of the raised portion. 2) and hot melt adhesive (softening point 100°C, application amount 30g / m 2 ) to form the second absorbent body 32. (3) The first absorbent body 31 and the second absorbent body 32 thus prepared were bonded together with a hot melt adhesive (softening point 90° C.) to obtain the absorbent body 3.

[0072] (Comparative Examples 1 to 11) For Comparative Examples 1 to 11, absorbent bodies 3 were produced under the conditions shown in Table 1 using the same production method as in Example 1.

[0073] [Evaluation test] The absorbent bodies 3 obtained in Example 1 and Comparative Examples 1 to 11 were subjected to the following four absorbency tests and five recyclability tests. The results are shown in Table 1.

[0074] 1. Absorbency (absorption speed) The absorption rate was measured by the following method: Figure 3 is an explanatory diagram of the method for measuring the absorption rate. (1) As shown in FIG. 3, first, the absorbent body 3 to be used as the sample 9 is spread out on a horizontal table 6 in a stretched state with the first absorbent body facing up, and is fixed to the table 6 (for example, by fixing both sides in a predetermined direction with packing tape). (2) Next, the absorption rate measurement jig 7 is placed on the center of the sample 9. The absorption rate measurement jig 7 is an acrylic jig having a rectangular bottom plate 7a and a tubular portion 7b extending upward from the center of the bottom plate 7a, with the lower end of the tubular portion 7b penetrating the bottom plate 7a. Next, two weights 8 are placed on the bottom plate 7a so as to sandwich the tubular portion 7b of the absorption rate measurement jig 7 from both sides. (3) Next, physiological saline (150 ml) is poured into the cylindrical portion 7b from above, and the time from the pouring until the level of the physiological saline is completely absorbed into the sample 9 is measured in seconds to two decimal places. This measured value is the absorption rate. (4) The measured absorption rate was evaluated according to the following criteria. ○: Absorption speed is less than 20 seconds △: Absorption speed is between 20 seconds and 30 seconds ×: Absorption speed is 30 seconds or more

[0075] The bottom plate 7a of the absorption rate measurement jig 7 has a width a of 100 mm and a length b of 140 mm. The cylindrical portion 7b of the absorption rate measurement jig 7 has an inner diameter of 36 mm and an outer diameter of 40 mm. The weight of the weights 8 is such that the load (pressure) acting on the sample 9 by the two weights 8 is 10 gf / cm. 2 The physiological saline solution is an aqueous solution of NaCl with a concentration of 0.9% (w / w). The accuracy of the stopwatch is ±0.0008%.

[0076] 2. Absorbency (amount of liquid returning) With the first absorbent body 31 facing upward, 300 ml of saline solution was poured towards the centre of the absorbent body 3, and after leaving it for 10 minutes, a filter paper (manufactured by ADVANTEC, No. 2 filter paper, diameter 55 mm) whose weight had been measured in advance was placed on the area where the saline solution was absorbed, and a pressure of 35 kgf / cm 2 After 60 seconds, the weight of the filter paper was measured, and the difference in the weight of the filter paper was taken as the amount of liquid returning. The measured amount of liquid returning was evaluated according to the following criteria. ○: Less than 0.5g of liquid leaked △: The amount of liquid returning is 0.5g or more and less than 1.0g ×: The amount of liquid returning is 1.0 g or more.

[0077] 3. Absorbency (comfort) The absorbent body 3 (Example 1 and Comparative Examples 1 to 11) was placed on a top sheet (basis weight 20 g / m 2 air-through nonwoven fabric) and back sheet (basis weight 20 g / m 2 Absorbent article 1 having the structure shown in Figure 2 was produced using a breathable polyethylene film (breathable polyethylene film). Twenty panelists wore absorbent article 1 and scored the comfort during exercise and sitting with 2 points for "comfortable," 1 point for "slightly bothersome," and 0 points for "uncomfortable," and the total points were calculated and evaluated according to the following criteria. ○: Total points are 30 or more △: Total points are between 10 and 30 points ×: Total points are less than 10 points

[0078] 4. Absorbency (comfort when absorbing body fluids) Absorbent core 3 was made to absorb 150 mL of a 10.9% aqueous solution of sodium chloride, and 20 panelists wore absorbent core 3. They scored the comfort during exercise and when sitting, giving 2 points for "comfortable," 1 point for "slightly bothersome," and 0 points for "uncomfortable," and the total points were calculated and evaluated according to the following criteria. ○: Total points are 30 or more △: Total points are between 10 and 30 points ×: Total points are less than 10 points

[0079] 5.Recyclability The recyclability was evaluated as follows: (1) The absorbent material 3 is placed in a dryer (VTR-115, manufactured by Isuzu Motors Ltd.) heated to 90°C (the softening point of structural hot melt) and left to stand for 20 minutes. After removing the absorbent material 3, it is allowed to drop naturally from a height of 1.5 m 30 times. (2) Next, the absorbents 3 are arranged in a centrifugal device (ODD-10RZ4RY model, manufactured by Daido Sangyo Co., Ltd.) with the skin-facing side of the absorbents 3 facing radially outward. When arranging multiple absorbents 3, they are arranged symmetrically so that they do not overlap each other. After centrifuging at a centrifugal force of 10 G for 5 minutes, the absorbents 3 are removed, and the SAP that has fallen off during centrifugation is collected. The mass is measured using an analytical balance (GR-200, manufactured by A&D Co., Ltd.) and recorded as the "primary SAP recovery amount (g)." (3) Next, the absorbent body 3 is placed in the same dryer heated to 100°C (the softening point of the supporting hot melt) and left to stand for 20 minutes. After removing the absorbent body 3, it is allowed to drop naturally from a height of 1.5 m 30 times. (4) Next, the absorbent bodies 3 are arranged in the same centrifugal device with the skin side of the absorbent bodies 3 facing outward in the radial direction. When arranging multiple absorbent bodies 3, they are arranged symmetrically so that they do not overlap each other. After centrifuging for 5 minutes at a centrifugal force of 10 G, the absorbent bodies 3 are removed, and the SAP that has fallen off due to centrifugation is collected. The mass is measured with the same measuring device and recorded as the "secondary SAP recovery amount (g)." (5) The amount of recovered SAP was calculated as follows and evaluated according to the following criteria: First yield (%) = (first SAP recovery amount) ÷ (first SAP mass) × 100 Second yield (%) = (amount of second SAP recovered) ÷ (mass of second SAP) × 100 ○: The first yield is 120% or less and the second yield is 80% or more △: The first yield is 120% or less and the second yield is 50% or more ×: Does not meet the above ○ or △ conditions

[0080] [Table 1]

[0081] From the above, according to the present disclosure, it has been confirmed that the two-layer absorbent body 3 consisting of a first absorbent body 31 placed on the skin side of the wearer and a second absorbent body 32 placed on the non-skin side of the wearer has sufficient absorption performance even though the main raw material of the superabsorbent polymer is derived from natural products. [Explanation of symbols]

[0082] 1. Absorbent articles 2 Topsheet 3. Absorbent 31 First absorber 311 Non-naturally derived superabsorbent polymers (first SAP) 312 Fluff Pulp 32 Second absorber 321 Naturally derived superabsorbent polymers (secondary SAPs) 322 Base nonwoven fabric 33 Structural hot melt 34 Hot melt adhesive for support 4 Back Seat 5 Slits 6 units 7. Absorption rate measurement jig 7a Absorption rate measurement jig (bottom plate) 7b Absorption rate measurement jig (tube part) 8 weights 9 Samples

Claims

1. An absorbent body having a two-layer structure comprising a first absorbent body arranged on the skin side of a wearer and a second absorbent body arranged on the non-skin side of the wearer, the first absorbent body is made of a non-naturally derived superabsorbent polymer and fluff pulp, and has a slit along the longitudinal direction; The second absorbent body is composed of a naturally derived highly absorbent polymer and a base nonwoven fabric. An absorbent body characterized by:

2. 2. The absorbent body according to claim 1, wherein the non-naturally derived superabsorbent polymer is a polyacrylic acid-based superabsorbent polymer, and the naturally derived superabsorbent polymer is a starch-based superabsorbent polymer.

3. The non-naturally derived superabsorbent polymer has a basis weight of 50 g / m ２ More than 400g / m ２ 3. The absorbent body according to claim 1, wherein:

4. The basis weight of the fluff pulp is 100 g / m ２ 800g / m or more ２ 3. The absorbent body according to claim 1, wherein:

5. 3. The absorbent body according to claim 1, wherein the slit has a width of 10% to 20% of the total width of the first absorbent body and a length of 10% to 100% of the total length of the first absorbent body.

6. The naturally derived superabsorbent polymer has a basis weight of 100 g / m ２ More than 1200g / m ２ 3. The absorbent body according to claim 1, wherein:

7. the first absorbent body and the second absorbent body are bonded with a structural hot melt; the naturally-derived superabsorbent polymer is fixed to the base nonwoven fabric with a supporting hot melt; 3. The absorbent body according to claim 1, wherein the supporting hot-melt adhesive has a softening point by the ring and ball method that is 10° C. or more higher than that of the structural hot-melt adhesive.

8. The amount of adhesive applied to the hot melt carrier is 15 g / m ２ 50g / m or more ２ 8. The absorbent body according to claim 7, characterized in that:

9. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and the absorbent body according to claim 1 or 2 disposed therebetween.

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