JP4208379B2 - Absorbent articles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an absorbent article that is less likely to cause liquid leakage due to warping.
[0002]
[Prior art and problems to be solved by the invention]
In an absorbent article such as a sanitary napkin, the absorbent body may be easily separated from other constituent materials during use, and liquid leakage may occur easily, particularly in a wet state after liquid absorption. It is easy to generate. In order to prevent this, means for applying an adhesive between the top sheet and the absorber and / or between the back sheet and the absorber has been used.
[0003]
However, since the adhesive hardly penetrates into the absorbent body, surface peeling between the absorbent body and other constituent materials could not be sufficiently suppressed. Also, if a large amount of adhesive is applied and the adhesive penetrates to the inside of the absorber, the texture of the absorbent article deteriorates due to the absorber becoming hard, and the absorption performance of the absorber decreases. Resulting in.
[0004]
Accordingly, an object of the present invention is to provide an absorbent article in which the surface peeling of the absorbent body is prevented without causing deterioration in the texture and absorption performance of the absorbent article, and the occurrence of kinks and leaks is suppressed.
[0005]
[Means for Solving the Problems]
The present invention relates to an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent interposed between the two sheets.
In the plan view, the absorber is configured such that a sparse area and a dense area are formed regularly or irregularly,
The top sheet and / or the back sheet is bonded and fixed to the absorber directly or via another member,
By providing an absorbent article in which the bonding strength of the top sheet and / or the back sheet is fixed to the absorber is greater in the sparse region of the absorber than in the dense region. Is achieved.
[0006]
In addition, as a preferred method for producing the absorbent article according to the present invention, in a plan view, at least one surface of an absorbent body formed by regularly or irregularly forming a sparse area and a dense area. The hot melt pressure-sensitive adhesive is applied in a predetermined pattern, and then the top sheet and / or the back sheet is arranged directly or via another member on the surface to which the hot-melt pressure-sensitive adhesive is applied. Provided is a method for manufacturing an absorbent article, which includes a step of joining and fixing the top sheet and / or the back sheet to the absorbent body directly or via the other member by applying heat. To do.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below based on preferred embodiments with reference to the drawings. 1 and 2 show a partially broken perspective view and a sectional view taken along line II of a sanitary napkin as an embodiment of the absorbent article of the present invention.
[0008]
The sanitary napkin 1 of the present embodiment has a vertically long shape, and has a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and a liquid-retaining absorption interposed between both sheets 2 and 3. It has a body 4. The top sheet 2 and the back sheet 3 extend from both side edges and front and rear ends of the absorbent body 4, and are bonded and fixed at the extending portion by a bonding means such as heat seal or hot melt adhesive.
[0009]
As the top sheet 2 and the back sheet 3, the same material as that used in conventional absorbent articles can be used. Moreover, as the absorbent body 4, a laminated body of pulp fibers, a laminated body of pulp fibers and a superabsorbent polymer, a dry pulp sheet in which pulp fibers are formed into a sheet with a binder, a nonwoven fabric, an absorbent paper, two sheets of absorption An absorbent sheet or the like in which the superabsorbent polymer is three-dimensionally held between the papers and the absorbent papers are integrated with each other is preferably used. In particular, the use of an absorbent sheet formed from an absorbent paper containing bulky cellulose fibers (for example, crosslinked cellulose fibers) and hot-melt adhesive fibers (for example, polyvinyl alcohol fibers) as the absorbent sheet can be further prevented. It is preferable from the point.
[0010]
The absorbent body 4 in the napkin 1 of the present embodiment is configured such that a sparse area and a dense area are regularly or irregularly formed in a plan view. Specifically, as shown in FIG. 1 and FIG. 2, the absorber 4 includes a region 5 in which an aperture is substantially formed (hereinafter referred to as an aperture region) and a non-perforated region 6 surrounding the region. It is configured. In the present embodiment, the aperture regions 5 are formed substantially uniformly and regularly in the planar direction of the absorber 4. And the opening area | region 5 is the said sparse area | region, and the non-opening area | region 6 is the said dense area | region. Here, “substantially” means that the fibers constituting the absorber 4 inevitably remain in the aperture region 5 in the process of forming the aperture.
[0011]
Then, as shown in FIG. 2, the top sheet 2 and the back sheet 3 are directly bonded and fixed by the predetermined bonding means 7 in the absorber 4 and its sparse area 5 and the dense area 6. Furthermore, the top sheet 2 and the back sheet 3 are joined and fixed via the joining means 7. The joining means 7 in this embodiment is adhesion by a hot melt pressure-sensitive adhesive. As a result, the top sheet 2 and the back sheet 3 are firmly fixed to the absorbent body 4 by the hot melt pressure-sensitive adhesive, so that it is effectively prevented that surface peeling occurs on the absorbent body 4 while the napkin 1 is worn. . As a result, the napkin 1 being worn is prevented from swaying, and liquid leakage is less likely to occur. Further, since the hot melt pressure-sensitive adhesive penetrates very easily in the thickness direction of the absorbent body 4 through the aperture region 5 in the absorbent body 4, the top sheet 2 and the back sheet 3 can be attached by using a small amount of hot melt pressure-sensitive adhesive. It can be firmly fixed to the absorber 4. As a result, the absorbent body is not hardened, and the texture and absorption performance of the absorbent article are not deteriorated. Furthermore, manufacturing costs can be reduced.
[0012]
Conventionally, it has been known that an opening is formed in an absorbent body of an absorbent article. However, the purpose of forming the opening is to guide and guide the liquid, and the top sheet and / or the back sheet as in the present invention. There is no example in which an opening is formed for the purpose of bonding and fixing.
[0013]
The bonding strength for fixing the top sheet 2 and / or the back sheet 3 to the absorber 4 is larger in the sparse region 5 of the absorber 4 than in the dense region 6. This makes it difficult for the absorbent body 4 and the top sheet 2 and / or the back sheet 3 to be peeled off from each other, so that their joining and fixing are ensured. In this case, it is sufficient that the sparse region 5 is larger than the dense region 6 with respect to the bonding strength of bonding and fixing to either one of the top sheet 2 and the back sheet 3. The sparse region 5 is larger than the dense region 6 with respect to the joint strength of the joint fixing of the top sheet 2 and the back sheet 3 to the absorber 4.
[0014]
The bonding strength of the sparse region 5 is preferably 50 to 400 cN from the viewpoint of preventing surface peeling between the absorbent body 4 and the top sheet 2 and / or the back sheet 3, and maintaining the texture and absorbent performance of the absorbent body 4. More preferably, it is 70-300 cN, More preferably, it is 100-200 cN. For the same reason, the bonding strength of the sparse region 5 with respect to the bonding strength of the dense region 6 is preferably 2 to 5 times, particularly 2.5 to 4 times. For the same reason, the bonding strength of the dense region 6 is preferably 40 to 500 cN, particularly 70 to 300 cN.
[0015]
It is sufficient that the bonding strength between the sparse region 5 and the dense region 6 satisfies the above relationship when dry (before liquid absorption), but satisfies the above relationship even when wet (after liquid absorption). If it exists, the absorber 4 and the liquid leak resulting from it will be prevented more effectively.
[0016]
The bonding strength of the sparse region 5 and the dense region 6 is measured as follows. The bonding strength of the sparse region 5 is obtained by cutting a portion of the napkin 1 where the sparse region 5 and the dense region 6 are formed on average into a size of 100 mm in length and 15 mm in width. The left and right width 10 mm portions of the measurement piece are cut out. Next, the measurement piece is immersed in water for 5 minutes. After taking out from the water, the absorber at one end in the longitudinal direction of the measurement piece and the top sheet or the back sheet are respectively attached to the chuck of a tensile tester (Tensilon tensile tester, manufactured by Toyo Baldwin), and the speed is 300 mm / min. Pull it 180 degrees. At this time, the maximum values of the portions corresponding to the sparse region 5 and the dense region 6 in the absorber 4 are defined as the respective bonding strengths.
[0017]
In order to prevent the absorption performance of the absorbent body 4 from being hindered, the joining and fixing of the absorbent body 4 to the top sheet 2 and the back sheet 3 are preferably intermittent.
[0018]
The sparse region (open region in the present embodiment) 5 in the absorbent body 4 has an area of one region of 1 to 100 mm ² , particularly 10 to 50 mm ² , so that the hot-melt adhesive sufficiently penetrates. It is preferable from the point. Moreover, it is preferable from the point which obtains sufficient joint strength that the opening area of the sparse area | region 5 with respect to the area of the absorber 4 is 5 to 50%, especially 10 to 40%. Although related to these, the number of sparse regions 5 formed is preferably 1 to 50 / cm ² , particularly 5 to 30 / cm ² , from the viewpoint of obtaining sufficient bonding strength.
[0019]
The sparse region 5 may not be formed over the entire area of the absorber 4, and may be formed only in a certain specific region. When a sparse region is formed in a specific region, the central region and / or the peripheral region of the absorber 4 is preferable as the region. When the sparse region is formed in the central region of the absorber 4, the liquid absorbability is improved and the absorber 4 is effectively prevented from being twisted. On the other hand, when the sparse region is formed in the peripheral region of the absorber 4, the warp in the peripheral region of the absorber 4 is effectively prevented, and particularly effective in preventing side leakage.
[0020]
As a method for forming the sparse region 5 in the absorbent body 4, when the sparse region 5 is formed of an aperture as in the present embodiment, through drilling with a punch pin that is heated or not heated can be cited. It is done. When the sparse region 5 is composed of a slit described later, cutting with a slit blade is used. Further, when the sparse region 5 is composed of a region where the density of the fiber material is low, air or water jet is used. As other methods for forming the sparse region 5, the methods described in JP-A-54-105893 and JP-A-5-253259 can be used. The sparse region 5 may be in any form of a planar structure and a three-dimensional structure (uneven structure).
[0021]
The hot melt pressure-sensitive adhesive used for joining and fixing the top sheet 2, the back sheet 3, and the absorber 4 is applied to one side or both sides of the absorber 4. There is no restriction | limiting in particular in the pattern and application quantity of application | coating, It determines suitably by the balance of the maintenance of the feel of the napkin 1, the delamination prevention of the absorber 4, and the absorption performance maintenance of the absorber 4. FIG. From the viewpoint of maintaining the absorption performance of the absorbent body 4, the hot melt adhesive is preferably applied intermittently, for example, in a spiral shape. In particular, the hot melt adhesive is preferably applied to the sparse region 5 and its vicinity. In the present invention, the total coating amount of the hot melt pressure-sensitive adhesive is preferably ² to ²⁰ g / m ² , particularly 5 to 15 g / m ² .
[0022]
When applying hot melt pressure-sensitive adhesive on both sides of the absorbent body 4, keep the amount of application on each side low, and when applying hot melt pressure-sensitive adhesive only on one side, apply to both sides It is preferable to increase the coating amount.
[0023]
The napkin 1 of this embodiment is preferably manufactured by the method described below. First, a hot melt pressure-sensitive adhesive is applied to at least one surface of the absorbent body 4 in a predetermined pattern. As described above, the coating pattern and the coating amount are appropriately determined. Next, the top sheet 2 and the back sheet 3 are arranged on each surface of the absorbent body 4 (application surface of the hot melt adhesive). Subsequently, pressure or heat is applied to these three members. For this means, for example, a pair of heated or unheated rolls is used. Then, the top sheet 2 and the back sheet 3 are bonded and fixed in the absorbent body 4 and its sparse region 5 and dense region 6 by pressing these three members with a pair of rolls. In this case, since the hot melt adhesive applied to the absorbent body 4 penetrates the sparse region 5, the bonding force between the absorbent body 4 and the top sheet 2 and the back sheet 3 is greater in the sparse region 5. Is larger than the dense region 6. Then, the napkin 1 is manufactured by attaching | subjecting to the process normally used.
[0024]
The present invention is not limited to the above embodiment. For example, for joining and fixing the top sheet 2 and the back sheet 3 to the absorbent body 4, in addition to a hot melt adhesive, a water-soluble binder such as polyvinyl alcohol, and a fusible fiber. Etc. can also be used.
[0025]
Moreover, the top sheet 2 and the back sheet 3 may be bonded and fixed to the absorber 4 through a region where slits (linear cuts) are formed in addition to the aperture region 5.
[0026]
Further, as a sparse region, a non-penetrating sparse region, for example, a region where the density of the fiber material constituting the absorber 4 is low is used in addition to the open region that penetrates the absorber 4 in the thickness direction. You can also.
[0027]
Moreover, in the said embodiment, although both the top sheet 2 and the back sheet 3 were joined and fixed to the absorber 4, it replaces with this and only one of the top sheet 2 and the back sheet 3 is joined and fixed to the absorber 4. May be.
[0028]
Moreover, in the said embodiment, although hot-melt adhesive exists in the sparse area | region 5 by osmosis | permeation, if the top sheet 2 and / or the back sheet 3 are joined and fixed to the absorber 4, one sparse It is not necessary for the hot melt pressure-sensitive adhesive to be present so as to fill the hot melt pressure sensitive adhesive in the region 5.
[0029]
In the above-described embodiment, the absorbent body 4 and the top sheet 2 and the back sheet 3 are in direct contact with each other, but instead, between the absorbent body 4 and the top sheet 2 and / or the absorbent body 4 and the back sheet. A member such as absorbent paper or nonwoven fabric may be interposed between the sheet 3 and the top sheet 2 and / or the back sheet 3 may be bonded to the absorbent body 4 via these members. In this case, the joining method and joining position between the absorber 4 and the member may be the same as or different from the joining method and joining position between the member and the top sheet 2 and / or the back sheet 3.
[0030]
In addition, these embodiments can be replaced with each other.
[0031]
【The invention's effect】
According to the absorbent article of the present invention, it is possible to achieve a comfortable use state without deterioration in texture and absorption performance.
Moreover, according to the absorbent article of the present invention, surface peeling between the absorbent body and the top sheet and / or the back sheet is suppressed, so that kinking is prevented and liquid leakage hardly occurs. In particular, even in a wet state after liquid absorption that is liable to occur, surface peeling between the absorbent body and the top sheet and / or the back sheet is suppressed, and dripping and liquid leakage due to this are prevented.
[Brief description of the drawings]
FIG. 1 is a perspective view of a sanitary napkin according to an embodiment of the absorbent article of the present invention, partially broken away.
FIG. 2 is a cross-sectional view taken along the line II in FIG.
[Explanation of symbols]
1 Sanitary napkin (absorbent article)
2 Top sheet 3 Back sheet 4 Absorber 5 Opening area (sparse area)
6 Non-open area (dense area)
7 Joining means

Claims (2)

In an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent interposed between both sheets,
In the plan view, the absorber is configured such that a sparse area and a dense area are formed regularly or irregularly,
The sparse region is a region in which openings are substantially formed,
The sparse region has one area of 10 to 50 mm ² and an opening area with respect to the area of the absorber of 5 to 50%.
The top sheet and / or the back sheet are joined to the absorbent body directly or via another member by a hot melt adhesive that has penetrated in the thickness direction of the absorbent body through the region where the openings are formed. Fixed,
In the absorbent article, the bonding strength of bonding and fixing the top sheet and / or the back sheet to the absorber is larger in the sparse region of the absorber than in the dense region. 2. The absorbent article manufacturing method according to claim 1, wherein, in a plan view, the absorbent body is configured such that a substantially perforated region and a non-perforated region are formed regularly or irregularly. The hot melt adhesive is applied in a predetermined pattern on at least one surface of the hot melt adhesive, and then the top sheet and / or the back sheet is disposed directly or via another member on the application surface of the hot melt adhesive. Thereafter, pressure or heat is applied to the top sheet and / or the back sheet directly or by the hot melt pressure-sensitive adhesive that has penetrated in the thickness direction of the absorber through the region where the openings are formed. The manufacturing method of an absorbent article which has the process of joining and fixing to the said absorber via another member.

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