JP3363312B2 - Disposable body fluid absorbent articles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disposable body fluid absorbent article such as a disposable diaper and a sanitary napkin. 2. Description of the Related Art Japanese Patent Application Laid-Open No. 46-1476 discloses a disposable diaper in which an elastic body such as a plastic mesh is inserted in the middle of a liquid-absorbent core in a thickness direction so as to enhance the shape retaining ability of the core. Is described. Also, Japanese Unexamined Patent Publication No.
Japanese Patent No. 228001 discloses that in a body fluid treatment absorbent article such as a disposable diaper or an incontinence pad, a net-shaped structural member made of a hydrophobic foam is disposed at an arbitrary position of a liquid-absorbent core to prevent the core from being wet. It is described that the shape retention and elasticity (cushioning property) can be maintained as in the case of drying. [0003] The diapers and sanitary napkins worn become stuffy when their absorbent cores are in a wet state, and the skin is easily rash. One of the means for eliminating such stuffiness is to make the wearing article air-permeable. In a wearing article such as the diaper of the related art, when a plastic net-like structural member is disposed in a liquid-absorbing core, a gap is easily generated between the member and a liquid-absorbing material such as pulp constituting the core. It is possible to improve the air permeability of the core. However, if the liquid-absorbing material that has absorbed body fluids is pulp, the rigidity of the fibers is reduced and the material is easily deformed.
Further, if it is a superabsorbent polymer powder, it swells and softens and becomes easily deformed. As a result, when body pressure is applied in a wet state, these liquid-absorbing materials are deformed so as to follow the surface shape of the net-shaped structural member and adhere to the member, and the liquid-absorbing material and the member In some cases, the air gap between them may decrease, resulting in a decrease in air permeability. Therefore, an object of the present invention is to provide a liquid-absorbent core that can maintain good air permeability even in a wet state. In order to solve the above-mentioned problems, the present invention is based on the premise that a liquid-absorbent core is interposed between a liquid-permeable top sheet and a liquid-impermeable back sheet. It is a disposable body fluid absorbent article. On this premise, the present invention is characterized in that a liquid-permeable thermoplastic synthetic resin sheet that extends substantially parallel to the topsheet is interposed in the middle of the thickness direction of the liquid-absorbent core. The thermoplastic synthetic resin sheet has a number of through holes, and a flexible peripheral wall extending in a direction from the upper surface to the lower surface of the sheet at the periphery of the through holes, and adjacent to each other in a cross section in the thickness direction of the sheet. A groove that opens in the direction from the upper surface to the lower surface is formed between the opposing portions of the peripheral walls of the corresponding through holes and the top surface portion of the sheet located between the through holes. Wherein the constituent materials of the core located on the upper surface side and the lower surface side of the thermoplastic synthetic resin sheet are in a continuous state in which the body fluid can be diffused. The details of the present invention will be described below with reference to the attached drawings, taking a sanitary napkin as an example of a disposable body fluid absorbent article according to the present invention. A sanitary napkin 1 shown in a partially cutaway view in FIG. 1 has a liquid-permeable top sheet 2 and a liquid-impermeable back sheet 3.
And a liquid-absorbent core 4 interposed between the two sheets 2 and 3. The front and back sheets 2 and 3 overlap at portions 6 and 7 extending from the periphery of the core 4 and are joined to each other. The core 4 includes an upper liquid absorbing layer 8, a lower liquid absorbing layer 9, and a perforated sheet 11 interposed between the two layers 8 and 9 and extending substantially in parallel with the topsheet 2. A large number of apertures 12 are formed in the sheet 11. The material of the topsheet 2 is 10 to 100 basis weight.
g / m ^{2 is} a thermoplastic synthetic fiber nonwoven fabric, and the material of the back sheet 3 is a thermoplastic synthetic resin sheet having a thickness of 0.02 to 0.1 mm. The core 4 includes liquid absorbing layers 8 and 9 at upper and lower portions.
Pulp of 30 to 100% by weight and 0 to 40% by weight
Of a superabsorbent polymer, and 0 to 20% by weight of a thermoplastic synthetic fiber. The aperture sheet 11 of the core 4 has a thickness of 0.0
It is obtained by thermoforming a thermoplastic synthetic resin sheet of 2 to 0.1 mm. FIG. 2 is a sectional view of a principal part taken along line II-II of FIG. The upper and lower liquid absorbing layers 8 and 9 are in a state where the pulp fibers are in contact with each other or entangled in the apertures 12 of the aperture sheet 11 so that the bodily fluid can be diffused from above to below. In order to ensure such diffusion, the core 4 has a lower liquid absorbing layer 9 having a higher fiber density than the upper liquid absorbing layer 8 and, when a superabsorbent polymer is used, the lower liquid absorbing layer 9 It may be configured to include more polymer than the upper liquid absorbing layer 8. The aperture sheet 11 has a top surface portion 16 of the sheet 11 located between the adjacent apertures 12 and a peripheral wall portion 17 of the aperture 12 extending downward from the top surface portion 16,
The top surface portion 16 contacts the upper liquid absorbing layer 8 from below, and the lower end of the peripheral wall portion 17 contacts the lower liquid absorbing layer 9 from above. FIG. 3 is a schematic perspective view of the aperture sheet 11. In the sheet 11, the peripheral wall 17 of the through hole 12 is
It is formed by bending a synthetic resin sheet of a material downward from the top surface portion 16. When the sheet 11 is viewed in a cross section in the thickness direction, the peripheral wall 17 of each of the openings 12 adjacent to each other across the top surface portion 16 has a groove 18 that opens downward together with the top surface portion 16. Has formed. The groove 18 extends in a mesh pattern over the entire lower surface of the sheet 11 and functions as a ventilation path that allows free flow of air and water vapor in the groove 18. The peripheral wall 17 is the same as or thinner than the top surface portion 16 and has flexibility, and imparts elasticity (cushioning property) to the core 4 in the thickness direction. The sheet 11 is made of a thermoplastic synthetic resin sheet, so that even if the core 4 changes from a dry state to a wet state, the sheet 1
1 hardly changes. Therefore, even if the napkin 1 is wet with the bodily fluid, the groove 18 is not easily crushed, and good air permeability can be maintained. In the present invention, the aperture area ratio of the aperture sheet 11 is preferably 30 to 80%. Aperture 12
Is preferably in the range of ² to 100 mm ² , and the shape of the opening 12 may be an appropriate shape other than the circular shape as in the illustrated example. The peripheral wall 17 preferably has a height of 0.3 to 5 mm. However,
The height does not need to be uniform. For example, the shape of the lower end of the peripheral wall 17 may be like a saw tooth. In addition, opening 12
In the circumferential direction, the peripheral wall 17 is preferably continuous, but may be partially missing and exhibit an intermittent state. The aperture sheet 11 is formed by pressing a heat-softened thermoplastic synthetic resin sheet such as polyethylene having a thickness of 0.02 to 0.1 mm to a molding die under the action of, for example, a vacuum pressure. It can be obtained by suction and rupture. The peripheral wall 17 is formed by the suction and the rupture. If the sheet 11 is hydrophobic, the inner surface of the groove 18 is hardly wet, which is advantageous in keeping the space through which the groove 18 can be ventilated as much as possible. However,
As the aperture sheet 11, the surface in which the top surface portion 16 and the peripheral wall 17 are in contact with the upper liquid absorbing layer 8 is subjected to a hydrophilic treatment, and the core 4
Can also facilitate the transfer of bodily fluids from the upper part to the lower part. According to the disposable body fluid absorbent article of the present invention, a thermoplastic synthetic resin sheet having a liquid-permeable opening and a gas-permeable groove is interposed between the liquid-absorbing cores. Even after the core absorbs the body fluid, it is possible to maintain good air permeability inside the core, and it is possible to prevent stuffiness and rash when wearing the article.

[Brief description of the drawings] FIG. 1 is a partially cutaway perspective view of a sanitary napkin. FIG. 2 is a sectional view of a main part taken along line II-II of FIG. 1; FIG. 3 is a perspective view of an aperture sheet. [Explanation of symbols] 1 Wearing articles (sanitary napkins) 2 Surface sheet 3 Back sheet 4 core 11 Liquid-permeable sheet (perforated sheet) 12 Through-hole (opening) 16 Top part 17 Side wall (peripheral wall) 18 grooves

Claims (1)

(57) [Claims 1] In a disposable body fluid absorbent article having a liquid-absorbent core interposed between a liquid-permeable topsheet and a liquid-impermeable backsheet, the liquid-absorbent core A liquid-permeable thermoplastic synthetic resin sheet that extends substantially in parallel with the topsheet is interposed in the middle of the thickness direction of the thermoplastic synthetic resin sheet, and the thermoplastic synthetic resin sheet has a large number of through-holes and the sheet at the periphery of the through-holes. And a flexible peripheral wall extending in a direction from the upper surface to the lower surface of the sheet. In a cross section in the thickness direction of the sheet, the peripheral wall of each of the adjacent through holes is located between the opposing portions of the adjacent peripheral walls and the through holes. The top surface portion of the sheet is formed with a groove that opens in a direction from the upper surface to the lower surface, and the core is positioned on the upper surface side and the lower surface side of the thermoplastic synthetic resin sheet through the through hole. The material is continuous so that the body fluid can be diffused The article in the state, it is characterized.