Absorbent article

Abstract

To provide an absorbent article including an absorber excellent in absorption performance while being thin.SOLUTION: An absorbent article including a top sheet, a back sheet and an absorber arranged between the top sheet and the back sheet is such that: the absorber has two-layer absorbers of an upper layer absorber and a lower layer absorber, a liquid permeable first intermediate sheet wrapping the two-layer absorbers, and a liquid permeable second intermediate sheet between the two-layer absorbers; the upper layer absorber contains 30 wt.% or more and 100 wt.% or less of pulp fibers having a basis weight of 20 g / m2 or more and 50 g / m2 or less, and 0 wt.% or more and 70 wt.% or less of a high water-absorbing polymer; the lower layer absorber contains only a high water-absorbing polymer; the upper layer absorber has in a short side direction center part, one slit where the absorbers do not exist in a long side direction; and the lower layer absorber has in a position overlapped on the slit of the upper layer absorber, one slit where the absorbers do not exist in a long side direction, and at least one slit where the absorbers do not exist in a direction crossing the slit of the lower layer absorber.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an absorbent article having an absorber that is thin and has excellent absorption performance.

Background Art

[0002] Conventionally, absorbent articles such as urine absorption pads, pantiliners, sanitary napkins, and paper diapers generally have a structure including a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber provided between the top sheet and the back sheet. At this time, the absorber often has a superabsorbent polymer (SAP) mixed in a base material such as pulp. A user absorbs liquids such as blood and urine (hereinafter referred to as body fluids) into the absorbent article by wearing the absorbent article on underwear or wearing a panty-type absorbent article.

[0003] Absorbent articles often have a situation where they absorb a large amount of body fluids due to, for example, long-term wearing. In order to prevent lateral leakage of body fluids and improve the fit feeling when wearing, development of the composition, structure, etc. for each component has been carried out.

[0004] Patent Document 1 discloses an absorbent article in which a water-absorbent sheet is interposed between a front sheet and a back sheet. The water-absorbent sheet includes a first sheet, a second sheet, and a water-absorbent resin powder fixed between these two sheets by an adhesive. A plurality of regions where the water-absorbent resin powder exists are formed between the first sheet and the second sheet. The plurality of these regions each extend in the longitudinal direction of the water-absorbent sheet and are arranged in parallel at a predetermined interval in the width direction of the water-absorbent sheet. Between adjacent regions where the water-absorbent resin powder exists and at both ends in the width direction of the water-absorbent sheet, there are non-existent regions where the water-absorbent resin powder does not exist. In the non-existent regions, the first sheet and the second sheet are joined, and a part of the non-existent region is a sheet peeling region. The sheet peeling region is configured such that the first sheet and the second sheet are peeled off by the liquid absorption and swelling of the water-absorbent resin powder.

[0005] There is a demand for absorbent articles that use a thin absorbent body from the viewpoints of wearing comfort, ease of movement, impact on the outer layer, storability, transportability, etc. Among the pulp fibers and superabsorbent polymers (SAPs) that make up the absorbent body, the thickness can be reduced by decreasing the proportion of pulp fibers. However, there is a problem that the water absorption rate decreases as the proportion of SAP increases. Also, reducing the overall weight of the absorbent body can reduce the thickness, but there is also a problem that the maximum absorption capacity of the absorbent article decreases and liquid backflow is likely to occur when a load is applied.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of such circumstances, and an object thereof is to provide an absorbent article having an absorbent body that is thin and has excellent absorption performance.

Means for Solving the Problems

[0008] To achieve such an object, the present invention is grasped by the following configuration. (1) The absorbent article of the present invention is an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet, wherein the absorbent body includes an upper absorbent body and a lower absorbent body, two layers of absorbent bodies, a liquid-permeable first intermediate sheet that wraps the two layers of absorbent bodies, and a liquid-permeable second intermediate sheet that exists between the upper absorbent body and the lower absorbent body. The upper absorbent body has a basis weight of 20 g / m 2 or more and 50 g / m 2Containing 30% by weight or more and 100% by weight or less of the following pulp fibers and 0% by weight or more and 70% by weight or less of the superabsorbent polymer, the lower absorbent body contains only the superabsorbent polymer, the upper absorbent body has one slit parallel to the long side direction at the center of the short side direction where there is no absorbent body, and the lower absorbent body has one slit parallel to the long side direction at a position overlapping with the slit of the upper absorbent body and at least one slit where there is no absorbent body in a direction intersecting the slit of the lower absorbent body.

Effect of the Invention

[0009] According to the present invention, it is possible to provide an absorbent article having an absorbent body that is thin and has excellent absorption performance.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0011] (Embodiment) To solve the above problems, a preferred embodiment (hereinafter referred to as an embodiment) of the absorbent article of the present invention will be described in detail below. The same elements are denoted by the same reference numerals throughout the description of the embodiment.

[0012] In this specification, "body fluid" means liquids such as blood and urine. The "long side direction" of an absorbent article or the like indicates the direction extending in the front-back direction of the user when the absorbent article is worn, and the "short side direction" of an absorbent article or the like indicates a direction lateral or orthogonal to the "long side direction". The "thickness direction" indicates a direction orthogonal to both the "long side direction" and the "short side direction".

[0013] Absorbent article An embodiment of the absorbent article according to the present invention will be described with reference to FIGS. 1, 2, and 3. The absorbent article 1 includes, in order from the side that contacts the skin, a liquid-permeable topsheet 2, an absorber 3, and a liquid-impermeable backsheet 4. The absorber 3 has an upper absorber 31 located in the upper layer, a lower absorber 32 located in the lower layer, a liquid-permeable first intermediate sheet 5 that wraps the upper absorber 31 and the lower absorber 32, and a liquid-permeable second intermediate sheet 6 that exists between the upper absorber 31 and the lower absorber 32. Further, the upper absorber 31 is provided with a slit 71 substantially parallel to the long side direction at the center of the short side direction, and the lower absorber 32 is provided with a slit 72 substantially parallel to the long side direction at a position overlapping the slit 71 and at least one slit 73 or more in a direction intersecting the slit 72.

[0014] The absorbent article 1 of the present invention is not particularly limited, and examples thereof include urine absorbent pads, panty liners, sanitary napkins, paper diapers, and the like.

[0015] (Topsheet) The base material of the topsheet 2 in the present embodiment only needs to have liquid permeability such that liquids such as blood and body fluids move to the absorber 3. For example, non-woven fabrics such as thermal bond non-woven fabrics typified by air-through non-woven fabrics, composite non-woven fabrics laminated with thermal bond / spun bond, apertured films such as apertured polyethylene films, polyethylene foams, foamed films such as urethane foams, or composite sheets laminated with these materials. Among these, from the viewpoint of preventing backflow of urine and the like, air-through non-woven fabrics and apertured films having a funnel-shaped cross-section are preferable.

[0016] In addition, in order to improve liquid permeability, it is preferable to emboss or perforate the topsheet 2. The processing method can be carried out without limitation using known methods. Further, in order to reduce irritation to the skin, it is also preferable to contain lotion, antioxidant, anti-inflammatory component, pH adjuster, antibacterial agent, moisturizing agent, etc. in the topsheet 2. Furthermore, from the viewpoints of strength and processability, the basis weight of the topsheet 2 is 10 g / m2 50 g / m or less is preferred. 2 is preferred.

[0017] (Backsheet) The base material of the backsheet 4 of the present embodiment may be any material having liquid impermeability such that the body fluid held by the absorber 3 does not leak to the underwear, and is formed from materials such as non-woven fabric, resin film, or a composite sheet obtained by laminating these. Such non-woven fabric is not particularly limited in the manufacturing method, and examples include spunbonded, meltblown non-woven fabric, or composite non-woven fabric obtained by laminating spunbonded / meltblown, spunbonded / meltblown / spunbonded, and their composite materials. Further, examples of such resin film include polyester, polyvinyl alcohol, polyethylene, polypropylene, and a composite film of polyethylene and polypropylene. It is preferable to provide an adhesive portion (not shown) for adhering to the underwear or the like on the backsheet 4.

[0018] From the viewpoints of strength and processability, the basis weight of the backsheet 4 is preferably 15 g / m 2 or more and 60 g / m 2 or less. Further, in order to prevent stuffiness during wearing, it is preferable to give the backsheet 4 moisture permeability. In order to provide moisture permeability, for example, blending a filler into the resin film of the base material or embossing the backsheet 4 can be mentioned. As the filler, calcium carbonate can be mentioned, and the processing method can be carried out without limitation by known methods.

[0019] (Absorber) The absorber 3 of the present embodiment is disposed between the topsheet 2 and the backsheet 4, and has two layers of absorbers 3, an upper layer absorber 31 and a lower layer absorber 32, a liquid-permeable first intermediate sheet 5 that wraps the two layers of the upper layer absorber 31 and the lower layer absorber 32, and a liquid-permeable second intermediate sheet 6 that exists between the upper layer absorber 31 and the lower layer absorber 32.

[0020] (Upper layer absorber) The upper absorbent body 31 is composed of pulp fibers as a base material and a superabsorbent polymer (SAP). The pulp fibers are not particularly limited as long as they are generally used in absorbent articles such as sanitary napkins, diapers, and urine absorbent pads. For example, they can be formed from materials such as fluff pulp, cotton, rayon, acetate, tissue, absorbent paper, and hydrophilic non-woven fabric. Among these, fluff pulp is preferred from the perspective of absorbency. Examples of such fluff pulp include wood pulp and non-wood pulp such as synthetic fibers and polymer fibers that have been fluffed into a cotton-like state.

[0021] The basis weight of the pulp fibers as the base material of the upper absorbent body 31 is 20 g / m 2 or more and 50 g / m 2 or less. If the basis weight of the pulp fibers is less than 20 g / m 2 , the shape of the upper absorbent body 31 cannot be maintained. If the basis weight of the pulp fibers exceeds 50 g / m 2 , the absorbent body 3 becomes thick.

[0022] The superabsorbent polymer (SAP) contained in the upper absorbent body 31 is not particularly limited as long as it can absorb body fluids and prevent backflow. For example, it can be formed from materials such as sodium polyacrylate, polyaspartic acid, (starch-acrylic acid) graft copolymer, (acrylic acid-vinyl alcohol) copolymer, (isobutylene-maleic anhydride) copolymer and its saponified product. Among these, sodium polyacrylate is preferred from the perspective of the absorption amount per unit weight.

[0023] In the upper absorbent body 31, the weight ratio of the pulp fibers is 30% by weight or more and 100% by weight or less, and the weight ratio of the superabsorbent polymer (SAP) is 0% by weight or more and 70% by weight or less. If the weight ratio of the pulp fibers is less than 30% by weight or the weight ratio of the superabsorbent polymer (SAP) exceeds 70% by weight, the water absorption rate decreases.

[0024] (Lower absorbent body) The lower absorber 32 contains only superabsorbent polymer (SAP). The superabsorbent polymer (SAP) contained in the lower absorber 32 is not particularly limited as long as it can absorb body fluids and prevent backflow. For example, it can be formed from materials such as sodium polyacrylate, polyaspartic acid, (starch-acrylic acid) graft copolymer, (acrylic acid-vinyl alcohol) copolymer, (isobutylene-maleic anhydride) copolymer and its saponified product. Among these, sodium polyacrylate is preferable from the viewpoint of the absorption amount per unit weight. Also, in order not to impair the absorption performance, the basis weight of the superabsorbent polymer (SAP) of the lower absorber 32 is 100 g / m 2 or more and 500 g / m 2 or less is preferably used.

[0025] (The first intermediate sheet) The first intermediate sheet 5 is liquid-permeable and is used to wrap the upper absorber 31 and the lower absorber 32 together. By the first intermediate sheet 5, body fluids can be quickly diffused to the absorber 3, and the shape of the two-layer absorber 3 can be stabilized.

[0026] As the base material of the first intermediate sheet 5, any material can be used as long as the permeation rate of body fluids is faster than that of the top sheet 2 and the body fluids can be quickly diffused to the absorber 3. For example, hydrophilic non-woven fabrics such as tissue, absorbent paper, airlaid non-woven fabric, and spunbond non-woven fabric can be mentioned.

[0027] The basis weight of the first intermediate sheet 5 is preferably 10 g / m 2 or more and 40 g / m 2 or less. When the basis weight is within the above range, the liquid can be sufficiently diffused over the entire upper surface of the absorber 3, and the shape of the absorber 3 can be stabilized.

[0028] (The second intermediate sheet) The second intermediate sheet 6 is liquid-permeable and is used to be interposed between the upper absorber 31 and the lower absorber 32. This second intermediate sheet 6 can quickly diffuse the body fluids that cannot be completely absorbed by the upper absorber 31 to the lower absorber 32.

[0029] As the base material of the second intermediate sheet 6, any hydrophilic material may be used, and examples thereof include hydrophilic nonwoven fabrics such as tissue, absorbent paper, airlaid nonwoven fabric, and spunbond nonwoven fabric.

[0030] (Long-side slit of the upper absorbent body) As shown in FIG. 1, the upper absorbent body 31 is provided with one slit 71 (also referred to as the "long-side slit of the upper absorbent body") that is substantially parallel to the long-side direction at the central portion in the short-side direction. The slit 71 penetrates in the thickness direction of the upper absorbent body 31, and there is no absorbent body in the slit 71. By having this slit 71, body fluid can quickly spread to the lower surface side of the upper absorbent body 31 and the lower absorbent body 32, and a high water absorption rate can be obtained.

[0031] The dimension of the slit 71 in the long-side direction is preferably 50% or more of the maximum dimension of the upper absorbent body 31 in the long-side direction. If the dimension of the slit 71 in the long-side direction is less than 50%, the water absorption rate is poor. The dimension of the slit 71 in the short-side direction (slit width) is preferably 5% or more and 20% or less of the maximum dimension of the upper absorbent body 31 in the short-side direction. If the dimension of the slit 71 in the short-side direction is less than 5%, the water absorption rate is poor, and if it exceeds 20%, the amount of liquid return increases.

[0032] (Long-side slit of the lower absorbent body) As shown in FIG. 2, the lower absorbent body 32 is provided with one slit 72 (also referred to as the "long-side slit of the lower absorbent body") that is substantially parallel to the long-side direction at a position overlapping with the slit 71 of the upper absorbent body 31. The slit 72 penetrates in the thickness direction of the lower absorbent body 32, and there is no absorbent body in the slit 72. By having this slit 72, body fluid can quickly spread from the upper absorbent body 31 to the upper surface side and the lower surface side of the lower absorbent body 32, and a high water absorption rate can be obtained.

[0033] The dimension of the slit 72 in the long side direction is preferably 50% or more of the maximum dimension of the lower absorber 32 in the long side direction. If the dimension of the slit 72 in the long side direction is less than 50%, the water absorption rate is poor. Here, the dimension of the slit 72 in the long side direction means the dimension of the lower absorber 32 in the long side direction before being divided into 8 parts, for example, not the dimension of each island of the lower absorber 32 divided into 8 parts shown in FIG. 2. On the other hand, the dimension of the slit 72 in the short side direction (slit width) is preferably 5% or more and 20% or less of the maximum dimension of the upper absorber 31 and the lower absorber 32 in the short side direction. If the dimension of the slit 72 in the short side direction is less than 5%, the water absorption rate is poor, and if it exceeds 20%, the amount of liquid return increases.

[0034] (Cross slit of the lower absorber) Furthermore, the lower absorber 32 is provided with at least one slit (also referred to as "cross slit of the lower absorber") 73 in a direction intersecting the slit 72. Here, the intersecting direction may be orthogonal or oblique to the slit 72. Also, when there are two or more slits 73, the slits 73 may or may not be parallel to each other. Note that the slit 73 penetrates in the thickness direction of the lower absorber 32, and there is no absorber in the slit 73. By having this slit 73, body fluid can quickly spread to the peripheral part of the lower absorber 32 via the slit 72 of the lower absorber 32 from the slit 71 of the upper absorber 31, and a high water absorption rate can be obtained.

[0035] The dimension of the slit 73 in the intersecting direction is preferably 50% or more of the maximum dimension of the lower absorber 32 in the short side direction. If the dimension of the slit 73 in the intersecting direction is less than 50%, the water absorption rate is poor. The slit width of the slit 73 is preferably 5% or more and 20% or less of the maximum dimension of the lower absorber 32 in the short side direction. If the dimension of the slit 73 in the short side direction is less than 5%, the water absorption rate is poor, and if it exceeds 20%, the amount of liquid return increases.

[0036] The present invention has been described above using embodiments. Needless to say, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. Also, it is obvious from the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

Example

[0037] The present invention will be described more specifically with the following examples. Note that the present invention is not limited to the description of the following examples as long as it does not exceed the gist thereof.

[0038] (Example) In this example, an air-through nonwoven fabric with a basis weight of 20 g / m 2 was used as the topsheet, and a breathable polyethylene film with a basis weight of 18 g / m 2 was used as the backsheet. A tissue with a basis weight of 16 g / m 2 was used as the first intermediate sheet, and a spunbond nonwoven fabric with a basis weight of 15 g / m 2 was used as the second intermediate sheet.

[0039] (Example 1) On the first intermediate sheet, 9.2 g of a superabsorbent polymer (SAP) was laminated in a range of 450 mm in length (long side direction) and 150 mm in width (short side direction), and then the second intermediate sheet was laminated. Further, 1.8 g of fluff pulp obtained by pulverizing and defibrating a pulp sheet and 3.7 g of a superabsorbent polymer (SAP) were mixed and laminated, and then the component members laminated by the first intermediate sheet were wrapped to produce an absorber having an upper layer absorber and a lower layer absorber.

[0040] The slits were formed as follows. The slit in the lower absorbent body is located at the center in the short side direction and is a single slit extending in the long side direction (dimension in the long side direction: 450 mm, dimension in the short side direction (slit width): 20 mm), and three slits extending in a direction perpendicular to the slit in the long side direction (dimension in the direction perpendicular to the long side direction: 150 mm, slit width dimension: 20 mm) were formed. The superabsorbent polymer (SAP) was laminated while avoiding the range of the slit part. Also, the slit in the upper absorbent body is located at the center in the short side direction at a position overlapping with the slit in the long side direction of the lower absorbent body, and a single slit extending in the long side direction (dimension in the long side direction: 300 mm, dimension in the short side direction (slit width): 20 mm) was formed. A mixture of fluff pulp and superabsorbent polymer (SAP) was laminated while avoiding the range of the slit part.

[0041] Then, the topsheet, backsheet, and absorbent body were joined together with a hot melt adhesive to form an integrated absorbent article.

[0042] (Examples 2 to 4, Comparative Examples 1 to 6) Under the conditions described in Table 1, an absorbent article was produced by the same manufacturing method as in Example 1.

[0043] The thickness, water absorption rate, and liquid return amount of the obtained absorbent article were measured and evaluated as follows. The results are shown in Table 1.

[0044] (Thickness of Absorbent Article) The thickness of the absorbent article was measured at the center in the long side direction and short side direction of the absorbent article using a thickness gauge (product name: Dial Thickness Gauge "PEACOCK (registered trademark)", manufactured by Ozaki Seisakusho Co., Ltd.) under a load condition of 35 gf / cm 2 and measured under the load condition of.

[0045] (Water Absorption Time (Water Absorption Rate)) At the center in the long side direction and short side direction of the absorbent article, a cylindrical measuring jig with an inner diameter of 30 mm and an outer diameter of 80 mm was installed, 40 mL of physiological saline was injected, and the time until all the physiological saline was absorbed by the absorbent article was measured and used as the water absorption rate.

[0046] (Liquid return volume) Inject 300 mL of physiological saline into the central portions in the long-side direction and short-side direction of the absorbent article, let it stand for 10 minutes, then place a filter paper (ADVANTEC No. 2, diameter 55 mm) whose weight has been measured in advance at the center of the injection part, and place a weight of 35 gf / cm 2 on the filter paper. After 1 minute has passed since placing the weight, measure the weight of the filter paper, and use the weight difference (g) of the filter paper before and after the test as the liquid return volume.

[0047]

Table 1

[0048] As a result, as shown in Table 1, all of the absorbent articles of Examples 1 to 4 were excellent in terms of thickness, water absorption rate, and liquid return volume. On the other hand, the absorbent articles of Comparative Examples 1 to 6 were inferior in any one of thickness, water absorption rate, and liquid return volume.

[0049] From the above, according to the present example, it was confirmed that the present invention can provide an absorbent article having an absorber that is thin and has excellent absorption performance.

Explanation of reference signs

[0050] 1 Absorbent article 2 Top sheet 3 Absorber 31 Upper absorber 32 Lower absorber 4 Back sheet 5 First intermediate sheet 6 Second intermediate sheet 71 Long-side slit of the upper absorber 72 Long-side slit of the lower absorber 73 Cross slit of the lower absorber

Claims

Claim 1 An absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorber disposed between the topsheet and the backsheet, wherein the absorber has two layers of absorbers, an upper layer absorber and a lower layer absorber, a liquid-permeable first intermediate sheet that wraps around the two layers of absorbers, and a liquid-permeable second intermediate sheet that exists between the upper layer absorber and the lower layer absorber, The upper absorbent body has a basis weight of 20 g / m ２ or more and 50 g / m ２ or less, contains 30% by weight or more and 100% by weight or less of pulp fibers, and 0% by weight or more and 70% by weight or less of a superabsorbent polymer. The lower absorbent body contains only the superabsorbent polymer. the upper layer absorber has one slit that is substantially parallel to the long side direction and where there is no absorber in the central portion in the short side direction, the lower layer absorber is characterized in that it has one slit that is substantially parallel to the long side direction and where there is no absorber at a position overlapping the slit of the upper layer absorber, and at least one slit where there is no absorber in a direction intersecting the slit of the lower layer absorber.

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