JP3288919B2 - Liquid permeable surface sheet for body fluid absorbent articles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-permeable topsheet used for body fluid-absorbing articles such as sanitary napkins and disposable diapers.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 57-82505 discloses a method in which a hydrophobic net-like sheet using a thermoplastic synthetic resin is superposed on a hydrophilic sheet and subjected to a hot embossing treatment. A technique used for a topsheet is disclosed.

Further, Japanese Patent Application Laid-Open No. 7-328061 discloses a topsheet in which a plurality of thermoplastic synthetic resin film strips are joined in parallel with each other on the upper surface of a liquid-permeable nonwoven fabric. The nonwoven fabric and the strip are welded to each other under heat and pressure to be integrated, and the nonwoven fabric portion except between the strips has liquid permeability.

In these known topsheets, a net-like sheet or a film strip of a thermoplastic synthetic resin is used to improve the strength of the topsheet, regulate the flow direction of bodily fluids in the topsheet, or absorb the topsheet into a core. It exerts a concealing effect on the performed menstrual blood and the like.

[0005]

In the above-mentioned prior art, the surface sheet obtained by welding a net-like sheet or film of a thermoplastic synthetic resin to a nonwoven fabric has a higher rigidity at a welded portion than at a non-welded portion. And thereby the flexibility of the entire sheet may be impaired. Such a topsheet does not easily adhere to the skin of the wearer of the article, and hinders the wearing feeling of the article and the improvement of leakproofness.

Accordingly, the present invention provides a liquid-permeable topsheet formed by continuously bonding filaments to the upper surface of a nonwoven fabric so that the bonding does not impair the flexibility of the topsheet. Another object of the present invention is to make the degree of damage, if any, small.

[0007]

According to the present invention, there is provided a body fluid absorbing article in which a plurality of thermoplastic synthetic resin filaments are joined to an upper surface of a liquid-permeable non-woven fabric made of thermoplastic synthetic fibers. Liquid permeable surface sheet. On this assumption, the present invention is characterized in that the plurality of filaments extend in one direction in parallel with each other, and the individual filaments are continuously joined to the upper surface of the nonwoven fabric along the longitudinal direction to be integrated,
The upper surface of the nonwoven fabric and the filament bonded thereto have undulations consisting of ridges and valleys extending in a direction perpendicular to the filaments and alternately repeating at a required pitch in the longitudinal direction of the filaments. Is to be.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sanitary napkin will be described as an example of a body fluid absorbing article with reference to the accompanying drawings, and the details of the liquid-permeable topsheet according to the present invention are as follows.

A sanitary napkin 1 shown in a partially broken perspective view in FIG. 1 has a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and a liquid-absorbent material interposed between these two sheets 2, 3. The front and back sheets 2 and 3 are joined to each other at a portion extending from the periphery of the core 4. Top sheet 2
Is composed of a nonwoven fabric 6 and a plurality of filaments 7 on the upper surface thereof and extending in parallel with each other in the longitudinal direction of the napkin 1.

FIGS. 2, 3, and 4 are a partially enlarged view of FIG. 1 and an end view taken along lines III-III and IV-IV of FIG. The nonwoven fabric 6 is formed by entanglement of thermoplastic synthetic fibers that have been subjected to hydrophilic treatment, and the plurality of thermoplastic synthetic resin filaments 7 are formed by continuously joining the lower surface portion 8 to the upper surface 9 of the nonwoven fabric 6. I have. Adjacent filaments 7 have the required spacing.

As shown in FIGS. 3 and 4, the upper surface 9 of the nonwoven fabric 6 and the filament 7 have peaks 11 and valleys 12 alternately repeated at a required period in the longitudinal direction of the filament 7. These peaks 11 and valleys 12 form the filament 7
1 in the width direction of the napkin 1 in FIG. As is clear from FIG. 4, the upper surface 9 of the nonwoven fabric 6 is located between the adjacent filaments 7.
Is at about the same level as, or higher than, the top 10 of the filament 7. The fiber density of the nonwoven fabric 6 may be substantially uniform in addition to the case where the fiber density gradually increases from the peak 11 toward the valley 12 as shown in FIGS. In addition, as shown in FIGS. 2 and 3, at the bottom of the valley 12, the fiber interval is locally relatively large, and an opening 15 extending between the upper and lower surfaces of the nonwoven fabric 6 may be formed. . Furthermore, the fiber density may be relatively high at the periphery of the opening 15. This latter aspect is illustrated in FIG. 3 as valley 12A.

As is apparent from the end view taken along the line VV of FIG. 2 shown in FIG. 5, the trough 12 has a second peak 17 alternately repeated in its longitudinal direction (left-right direction in FIG. 2). And a second valley 18. However, the height of the second peak 17 does not exceed the height of the peak 11. Second valley 1
8 may have a fiber density higher than that of the second peak 17 and may have openings 15 as shown in FIGS.

FIG. 6 shows another embodiment of the topsheet 2 with an end view similar to FIG. The upper surface of the topsheet 2 is the same as that of FIG. 3, but the lower surface is not flat, the concave portion 31 is formed on the lower surface of the peak portion 11, and the convex portion 32 is formed on the lower surface of the valley portion 12.

In the sanitary napkin 1 using the topsheet 2 having such a configuration, since the topsheet 2 has the bellows structure including the peaks 11 and the valleys 12, it is easy to bend in the longitudinal direction. Fits well to the wearer's body. Most of the excreted menstrual blood diffuses from a place where the fiber density is low to a place where the fiber density is high, that is, from the peak 11 to the valley 12, and moves to the core 4 from the bottom of the valley 12. In the topsheet 2, since the peak 11 mainly comes into contact with the skin and the valley 12 tends to separate from the skin, menstrual blood diffused into the valley 12 moves away from the skin, and the wet feeling caused by wearing the napkin 1 occurs. Contributes to the reduction of If there is a large opening 15 at the bottom of the valley 12, menstrual blood in the valley 12 can be transferred to the core 4 more quickly. In particular, when the topsheet 2 is in the mode shown in FIG. 6, the peripheral edge of the opening 15 adheres well to the core 4, and the transfer of menstrual blood is promoted. When the upper surface 9 of the nonwoven fabric 6 is at the same level as or higher than the top 10 of the filament 7, the filament 7 is less likely to touch the wearer's skin and give the synthetic resin a unique feel, and the topsheet 2 Will feel like cloth. When the topsheet 2 has undulations on the upper and lower surfaces as shown in FIG. 6, the cushioning property when it comes into contact with the skin is good.

The outline of the process for manufacturing the topsheet 2 is as follows. First, a continuous nonwoven web to be the nonwoven fabric 6 is supplied in one direction at a required speed. On the other hand, a plurality of filaments to be the filaments 7 are extruded using an extruder, and are placed on the upper surface of the web so as to be arranged in parallel along the supply direction. While the filament is in the softened state, the web and the filament are embossed to join them together, and the peaks and valleys to be the peaks 11 and valleys 12 of the topsheet 2 are formed. Form and obtain a composite sheet. This composite sheet is cut into required dimensions and used as a top sheet 2.

In this step, an example of the nonwoven fabric web is made of a core-sheath composite fiber of polyethylene and polypropylene having a weave of 4 d and a cut length of 51 mm (ES fiber EAC-704V06 manufactured by Chisso Corporation), weighing 20 g / m ^2.
There is a thermal bond nonwoven fabric having an apparent thickness of 0.2 mm and a fiber surface subjected to hydrophilic treatment to a required degree. As an example of the filament, low-density polyethylene (Exelen VL800 manufactured by Sumitomo Chemical Co., Ltd.) having a density of 0.905 and a melt flow rate of 20 accounts for 95 to 60% by weight, and a processing aid for facilitating the formation of the filament. A width of 0.1 to 1.0 mm obtained by extruding a mixture containing 5 to 40% by weight of microcrystalline wax as a blood repellent, TiO ₂ as a coloring agent,
There is a filament with a thickness of 0.01-0.07 mm. The filaments are preferably arranged on the nonwoven web at parallel intervals of 0.3 to 2 mm.

[0017]

In the topsheet according to the present invention, the upper surface of the nonwoven fabric and the filaments continuously bonded thereto extend in the direction orthogonal to the filaments, and have the peaks and valleys which repeat in the longitudinal direction of the filaments. Having. Such a topsheet has a bellows structure between the peaks and the valleys, and the filament can be easily bent in the longitudinal direction and has high flexibility. Therefore, the bodily fluid absorbent article using this topsheet has good adhesion to the skin when the longitudinal direction of the filament is curved along the body.

[0018] The topsheet is made of a soft nonwoven fabric that is in contact with the skin when the top surface of the nonwoven fabric is approximately the same as or higher than the top of the filament between adjacent filaments, and is relatively rigid. Since the high-filament filaments are less likely to touch the skin, the wearing feeling of the wearing article can be improved.

In a mode in which the fiber density of the nonwoven fabric gradually increases from the peak to the valley, the body fluid tends to diffuse from the peak to the valley. Such diffusion promotes excreted bodily fluids to quickly move away from the skin and migrate to the core, as the valleys tend to move away from the skin. Therefore, the bodily fluid absorbent article using the topsheet has a slight wet feeling when used.

In a mode in which the topsheet has a relatively large opening at the bottom of the valley, if the lower peripheral portion of the opening is in contact with the core, the body fluid that diffuses and collects in the valley quickly transfers to the core. I do. Therefore, in the bodily fluid absorbent article using the topsheet, the wet feeling when worn is further reduced. In particular, when the fiber density is relatively high at the periphery of the opening, the effect of reducing the feeling of wetness becomes more remarkable.

Further, when the topsheet has a convex portion on the lower surface, the bottom of the valley closely adheres to the absorbent core, and the transfer of the body fluid diffused into the valley to the core is promoted.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view of a sanitary napkin.

FIG. 2 is a partially enlarged view of a topsheet.

FIG. 3 is an end view taken along line III-III in FIG. 2;

FIG. 4 is an end view taken along line IV-IV of FIG. 2;

FIG. 5 is an end view taken along line VV of FIG. 2;

FIG. 6 is a view similar to FIG. 3, illustrating one embodiment of a topsheet.

[Explanation of symbols]

 2 Top sheet 6 Non-woven fabric 7 Filament 9 Upper surface 10 Top 11 Peak 12 Valley 15 Opening

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI D06M 17/00 (58) Investigated field (Int.Cl. ⁷ , DB name) A61F 13/15-13/84

Claims (6)

(57) [Claims] 1. A liquid permeable surface sheet of a body fluid absorbent article comprising a plurality of thermoplastic synthetic resin filaments bonded to an upper surface of a liquid permeable nonwoven fabric made of thermoplastic synthetic fibers, wherein the plurality of filaments are one of Direction, the individual filaments are continuously joined to the upper surface of the non-woven fabric along its longitudinal direction to be integrated, and the upper surface of the non-woven fabric and the filament bonded thereto are in a direction orthogonal to the filaments. Wherein the topsheet has undulations of peaks and valleys that alternately repeat at a required pitch in the longitudinal direction of the filament. 2. The topsheet according to claim 1, wherein the valley has a relatively small ridge that repeats at a required pitch in a direction perpendicular to the filament. 3. The surface sheet according to claim 1, wherein the upper surface of the nonwoven fabric is substantially the same as or higher than the top of the filament between adjacent filaments. 4. The surface sheet according to claim 1, wherein the fiber density of the nonwoven fabric gradually increases from the peaks to the valleys forming the skirts. 5. The nonwoven fabric according to claim 1, wherein a fiber interval is relatively large at a bottom of the valley portion, thereby forming an opening extending between upper and lower surfaces of the nonwoven fabric. Surface sheet as described. 6. The topsheet according to claim 1, wherein the lower surface of the nonwoven fabric protrudes downward at a portion corresponding to the valley.