JP4540087B2 - Absorbent articles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an absorbent article used for absorbent articles such as sanitary napkins, panty liners, and incontinence pads for absorbing menstrual blood, cages, etc., and more specifically, a thin absorbent body using an airlaid nonwoven fabric. The present invention relates to an absorbent body that improves softness and cushioning properties, and reduces wearing discomfort during use to improve wearability, and an absorbent article using the same.
[0002]
[Prior art]
Since bodily fluid absorbent articles such as sanitary napkins, panty liners, and incontinence pads have been provided on the market, various improvements have been accumulated with respect to absorbent bodies using superabsorbent resins.
[0003]
As is well known, a highly water-absorbent resin absorbs and swells when it comes into contact with water and becomes a gel, and once absorbed, it has the property that it does not separate even if a certain amount of pressure is applied. It shows tremendous water absorption such as reaching tens to thousands of times. Although the high water-absorbing resin alone exhibits the above-mentioned water-absorbing power, it cannot exhibit its water-absorbing power unless it is swollen to some extent and has a slow water-absorbing speed. , Crushed powder or pellets.
[0004]
In recent years, in the case of this type of absorbent article, there is a problem that it is bulky and inconvenient to carry or has poor storage properties, and it has become thinner and more compact due to demands for efficient logistics and resource saving. Has come to be realized. Since the water absorption cannot be reduced even if the absorber is made thin or compact, it is usually dealt with by increasing the content ratio of the superabsorbent resin, but if the content ratio of the superabsorbent resin is increased too much In other words, so-called “gel blocking” occurs in which the gap is extremely reduced between the swollen water-absorbing polymer particles, and the desired water-absorbing power cannot be expressed. As a result, permeation of menstrual blood or the like is inhibited by the binding between the water-absorbing polymer particles, and a phenomenon in which menstrual blood or the like that has been impeded is reversed and flows out again can be seen.
[0005]
Various methods for suppressing the gel blocking have been proposed, but at present, the content ratio of the superabsorbent resin to the total weight of the superabsorbent resin and the water absorbent material such as pulverized pulp is generally within 80%, preferably within 50%. In many cases, the thickness is reduced by applying a severe press to the absorber.
[0006]
In addition, with increasing the content ratio of the superabsorbent resin and relatively reducing the fiber component, there arises a problem that the absorbent body is liable to crack or break easily. Proposed methods include crosslinking cellulose of pulp with an appropriate crosslinking agent, adding a binder resin, mixing hot-melt fibers, and bonding the fibers together by heat treatment.
[0007]
[Problems to be solved by the invention]
However, when the absorber is thinned by pressing, the product density of the absorber (pulverized pulp, etc.) is extremely increased, so that the water absorption capacity decreases and the absorber becomes hard and the wearer feels uncomfortable. You will feel. Furthermore, wrinkles are formed largely, and there is a problem that leakage is likely to occur.
[0008]
In addition, in the case of the above-mentioned countermeasures against twisting or cracking of the absorbent body, problems such as a decrease in the body fluid absorption capability of the fiber itself or a swellability of the superabsorbent resin occur due to the crosslinking treatment or the heat treatment. There is a problem that the superabsorbent resin is completely covered with the binder, resulting in a decrease in water absorption capability, and the rigidity of the absorbent body is increased due to the binder and heat fusion, and the feeling of wearing is impaired.
[0009]
Therefore, the first problem of the present invention is to improve the softness and cushioning properties of the thin absorbent body, reduce the uncomfortable feeling during use and improve the wearing feeling, and enhance the absorption speed and diffusion preventing effect of body fluids , Further, the strength is improved and the absorber is prevented from twisting, cracking, and tearing.
[0010]
[Means for Solving the Problems]
In order to solve the first problem, as an invention according to claim 1, in an absorbent article in which an absorbent body is interposed between a liquid-permeable top sheet and a liquid-impervious back sheet,
The absorbent body is an absorbent body formed in the form of a sheet mainly composed of pulp and a highly water-absorbent resin, and a heat-fusible nonwoven fabric made of chemical fibers is laminated on the upper and lower surfaces or the upper surface of the absorbent body. In the region including the body fluid discharge site, a wave-like process in which concave portions and convex portions continue along the longitudinal direction of the absorbent article is applied together with the heat-fusible nonwoven fabric, and the wave-like processed region is measured by a KES compression tester. An absorbent article having a WC value (compression energy value) of 0.25 to 1.5 gf · cm / cm ² is provided.
[0011]
As the present invention according to claim 2, in an absorbent article in which an absorber is interposed between a liquid-permeable top sheet and a liquid-impervious back sheet,
The absorbent body is an absorbent body formed in the form of a sheet mainly composed of pulp, chemical fiber and highly water-absorbent resin, and a heat-fusible nonwoven fabric made of chemical fibers is laminated on the upper and lower surfaces or upper surface of the absorbent body. In addition, a wave-like process in which a concave part and a convex part continue along the longitudinal direction of the absorbent article is applied to an area including at least a body fluid discharge site together with the heat-fusible nonwoven fabric , and KES compression of the wave-like processed area An absorbent article characterized by having a WC value (compression energy value) by a tester of 0.25 to 1.5 gf · cm / cm ² is provided.
[0012]
The present invention according to claim 3 provides the absorbent article according to claim 2, wherein the chemical fiber content is 5 to 30%.
[0013]
As the present invention according to claim 4 , there is provided an absorbent article according to any one of claims 1 to 3 , wherein the apparent thickness of the wavy processed region of the absorber is 0.5 to 3.0 mm.
[0014]
In the present invention according to claim 5 , the absorber thickness before corrugation is 0.3 to 2.0 mm, and the apparent thickness after corrugation is 1.6 to 10 times the absorber thickness before corrugation. The absorbent article according to any one of claims 1 to 4 , which has been subjected to wave processing so as to be obtained.
[0015]
As the present invention according to claim 6 , in the wavy processing region of the absorber, the absorber thickness of the recesses and projections is 0.3 to 2.0 mm, and absorption of the connecting portion that connects the recesses and projections body thickness is the 0.1～1.8Mm, claim 1-5 or the absorber thickness of the connecting portion are subjected to a wave-like process to be smaller than the absorber thickness of the concave and convex portions An absorbent article is provided.
[0016]
As the present invention according to claim 7, the absorbent article according to any one of claims 1-6 interval between between the concave or convex portion is 1.0~10mm is provided.
[0017]
The present invention according to claim 8 provides the absorbent article according to any one of claims 1 to 7 , wherein the content of the superabsorbent resin is 10 to 60%.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially broken perspective view of an absorbent article 1 according to the present invention.
[0019]
The absorbent article 1 is mainly used for applications such as panty liners, sanitary napkins, cage sheets, incontinence pads, etc., for example, as shown in FIG. Between the liquid-permeable surface sheet 3, as shown in the figure, the absorbent body 4 or an absorbent body unit 6 comprising the absorbent body 4 and the crepe paper 5 surrounding the absorbent body 4 is interposed. . Around the absorber 4, the liquid-impervious back sheet 2 and the liquid-permeable top sheet 3 are bonded together by an adhesive means such as a hot melt adhesive.
[0020]
The liquid-impervious back sheet 2 is made of a sheet material having at least water shielding properties, such as polyethylene and polypropylene. In addition to this, a laminated nonwoven fabric obtained by laminating a nonwoven fabric on a polyethylene sheet or the like, and further a waterproof film interposed. After substantially ensuring liquid impermeability, a nonwoven fabric sheet (in this case, a waterproof film and a nonwoven fabric constitute a liquid impervious back sheet) or the like can be used. In recent years, those having moisture permeability tend to be suitably used from the viewpoint of preventing stuffiness. The water- and moisture-permeable sheet material is a microporous material obtained by melting and kneading an inorganic filler in an olefin-based resin such as polyethylene or polypropylene to form a sheet, and then stretching in a uniaxial or biaxial direction. A sheet is preferably used.
[0021]
As the liquid-permeable surface sheet 3, a non-porous or perforated nonwoven fabric or a porous plastic sheet is suitably used. Examples of the material fibers constituting the non-woven fabric include synthetic fibers such as olefins such as polyethylene and polypropylene, polyesters and polyamides, recycled fibers such as rayon and cupra, and natural fibers such as cotton. In addition, a composite fiber such as a core-sheath fiber, a side-by-side fiber, or a split fiber having a fiber having a high melting point as a core and a fiber having a low melting point as a sheath can be suitably used.
[0022]
Regarding the processing method, a nonwoven fabric obtained by an appropriate processing method such as a spunlace method, a spunbond method, a thermal bond method, a melt blown method, or a needle punch method can be used. Among these processing methods, the spunlace method is excellent in terms of flexibility and drapeability, and the thermal bond method is excellent in terms of being bulky and soft.
[0023]
The absorbent body 4 interposed between the liquid-impervious back sheet 2 and the liquid-permeable top sheet 3 is, for example, a mixture of a superabsorbent resin in pulp or a mixture of chemical fibers in the pulp. In addition, those mixed with a superabsorbent resin are used.
[0024]
Examples of the pulp include chemical fibers obtained from wood, cellulose fibers such as molten pulp, and artificial cellulose fibers such as rayon and acetate. Softwood pulp having a longer fiber length than hardwood pulp functions and It is preferably used in terms of price. The production method is preferably one produced by the airlaid method.
[0025]
Examples of the superabsorbent resin include a cross-linked polyacrylate, a self-crosslinked polyacrylate, a saponified acrylate-vinyl acetate copolymer cross-linked product, and a cross-linked isobutylene / maleic anhydride copolymer. , A crosslinked polysulfonate, and a partially crosslinked water-swellable polymer such as polyethylene oxide and polyacrylamide. Among these, those based on acrylic acid or acrylate that are excellent in water absorption and water absorption speed are preferred. In the production process of the highly water-absorbent resin having the water absorption performance, the water absorption force and the water absorption speed can be adjusted by adjusting the crosslinking density and the crosslinking density gradient. The content of the superabsorbent resin is preferably 10 to 60%. When the content of the superabsorbent resin is less than 10%, sufficient absorbability cannot be provided, and when it exceeds 60%, the entanglement between the pulp fibers disappears, the sheet strength decreases, and tears, cracks, etc. Is likely to occur.
[0026]
As said chemical fiber, hydrophobic synthetic fibers, such as olefin type, such as polyethylene or a polypropylene, a polyester type, and a polyamide type, can be used conveniently. This mixing of the chemical fibers is for providing flexibility to the absorbent body 4 by interposing between the hydrogen bonds between the pulps. The content of the chemical fiber is preferably 5 to 30%. When the content rate is less than 5%, it is not possible to give remarkable flexibility as compared with the chemical fiber not mixed, and when the content rate exceeds 30%, the water absorption performance is lowered and the body fluid is retained. become unable.
[0027]
In the present invention, in particular, the absorbent body 4 is subjected to corrugated processing in which the concave portions 4b and 4b and the convex portions 4a and 4a are continuous along the longitudinal direction of the absorbent article, and the corrugated region is subjected to KES compression. Those having a WC value (compression energy value) by a tester of 0.25 to 1.5 gf · cm / cm ² are used. By subjecting the absorber 4 to the wavy processing, flexibility in the width direction of the absorber is improved, cushioning is imparted to the surface of the absorber, and discomfort at the time of wearing is eliminated. Further, the corrugated recesses 4b, 4b ... serve as damming grooves to prevent the diffusion of body fluids, and the body fluid that has flowed into the recesses 4b, 4b ... increases the contact area with the absorber, thereby improving the absorption rate. Then, it is quickly absorbed by the absorber 4 side. Furthermore, when the absorbent body 4 is subjected to a wave-like process, even when the liquid-permeable surface sheet 3 is a non-woven fabric, the dry feeling is improved as compared with the conventional one, and a porous plastic sheet is used. At the same time, the tendency (dry feeling) becomes more prominent.
[0028]
The KES compression tester (manufactured by Kato Tech Co., Ltd.) is a tester for simulating the sensation of touching an object with a human fingertip, and measures compression energy, compression hardness, compression recovery, etc. Is possible. The measurement is performed by compressing the sample under the conditions of speed: 0.01 cm / sec, compression area: 2 cm ² , sensitivity: 2 (force gauge 200 g / 10 v), compression load: 50 gf / cm ² , and correlation between pressure and deformation. LC (compression hardness), WC (compression energy), and RC (compression recoverability) are calculated.
[0029]
First, the LC (compression hardness) is represented by [a + b area] / [ΔABC area] in the correlation diagram between the pressure and the deformation amount shown in FIG. It becomes evaluation that is hard. The WC (compression energy) is represented by [a + b area], and the larger the value, the easier it is to compress. The last RC (compression recoverability) is indicated by [area b] / [area a + b], and the evaluation is such that the closer the value is to 100%, the recoverability is. Among these test items, WC (compressed energy) is preferably used as an index for the softness determined by sensory evaluation. When the WC value (compression energy value) is less than 0.25 gf · cm / cm ² , the absorbent body 4 does not come out softly and still feels strange when worn. Further, when the WC value (compression energy value) exceeds 1.5 gf · cm / cm ² , the absorbent body 4 is likely to be twisted or cracked, and the shape cannot be maintained.
[0030]
In cross-sectional view shown in FIG. 2, the thickness _{T K} of the apparent of the absorbent body 4 is preferably set to 0.5 to 3.0 mm. Since the present absorbent body 4 is used as a thin absorbent body, it is desirable that the thickness upper limit value is 3 mm, and if the thickness is too thick, the wavy workability is deteriorated.
[0031]
Further, as the degree of the wave processing, the absorber thickness before the wave processing is 0.3 to 2.0 mm, and the apparent thickness after the wave processing is 1.6 to 10 times the thickness of the absorber before the wave processing. It is desirable to apply a corrugated process. When the thickness magnification is less than 1.6 times, sufficient softness and cushioning properties are not imparted, and sufficient body fluid absorption rate and diffusion preventing effect cannot be expected. Further, when the thickness magnification exceeds 10 times, it becomes difficult to perform the wave processing, and it becomes impossible to maintain the shape of the wave processing in the product state.
[0032]
Further, in the wavy processing of the absorber 4, the absorber thicknesses t ₂ and t ₁ of the recesses 4b, 4b... And the protrusions 4a, 4a. The connecting portions 4c, 4c,... Connecting the convex portions 4a, 4a,... Have an absorber thickness of 0.1 to 1.8 mm, and the connecting portions 4c, 4c,. Desirably, the corrugation is performed so as to be smaller than the absorber thickness of 4a, 4a. By making the absorber thickness of the connecting portions 4c, 4c... Relatively small, the connecting portions 4c, 4c... Are easily deformed as bent portions, and the flexibility is improved.
[0033]
On the other hand, it is desirable to perform wave processing with a linear density of 1.0 to 10 mm between the concave portions 4b and 4b or between the convex portions 4a and 4a. When the concave or convex spacing W is less than 1.0 mm, the cushion effect, the improvement of the bodily fluid absorption rate and the bodily fluid diffusion preventing effect cannot be expected, and the absorber 4 is easily broken. When the concave or convex interval W exceeds 10 mm, the effects intended by the present invention such as flexibility imparting effect, cushioning effect, improvement of bodily fluid absorption rate, and bodily fluid diffusion preventing effect cannot be expected.
[0034]
It is desirable that the absorbent body 4 is surrounded by the crepe paper 5 in order to maintain the shape and quickly diffuse menstrual blood and prevent the menstrual blood and the like once absorbed. Moreover, the planar shape of the absorber 4 may be an oval shape as illustrated, or may be a fit cut shape (a gourd shape) to soften the contact with the crotch portion.
[0035]
Incidentally, in the absorbent body 4, as shown in FIG. 3 (A), a heat-fusible nonwoven fabric 7 made of chemical fibers is laminated on the upper and lower surfaces of the absorbent body 4, or as shown in FIG. 3 (B). As described above, a heat-fusible nonwoven fabric 7 made of a chemical fiber can be laminated on the upper surface, and wave-like processing can be performed together with the heat-fusible nonwoven fabric 7. By providing the heat-fusible nonwoven fabric 7 integrally on at least one surface side of the absorbent body 4, strength is imparted to the absorbent body 4, and twisting, cracking and tearing can be effectively prevented. Moreover, in the said form example, although the said wavy process was formed over substantially the whole region of the absorber 4, you may make it form partially with respect to the area | region containing a bodily fluid discharge part at least.
[0036]
In order to perform the corrugated processing on the absorber 4, as shown in FIG. 4, the corrugated roll 8 having a large number of convex strips 8 a continuous in the circumferential direction on the roll surface, and the corresponding position of the convex strip 8 a An anvil roll 9 having a recess 9a is disposed oppositely, and the absorber strip 4 'is passed between the two rolls 8 and 9, so that the absorber strip 4' is continuously waved.
[0037]
【The invention's effect】
As described above in detail, according to the inventions of claims 1 to 8, the softness and cushioning properties of the thin absorbent body can be improved, the uncomfortable feeling during use can be reduced, and the wearing feeling can be improved. It becomes possible to enhance the absorption rate and the diffusion preventing effect.
[0038]
Further, in addition to the effect on SL, it is possible to improve the strength, so that twisting of the absorbent body, cracking and tear can be prevented.
[Brief description of the drawings]
FIG. 1 is a partially broken perspective view of an absorbent article 1 according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of the absorbent body 4;
FIG. 3 is a view showing an aspect in which a heat-fusible nonwoven fabric 7 is laminated on an absorbent body 4;
FIG. 4 is a diagram of a wavy machining procedure for the absorber 4;
FIG. 5 is a correlation diagram between pressure and deformation, showing the KES compression test results.
[Explanation of symbols]
[0039]
DESCRIPTION OF SYMBOLS 1 ... Absorbent article, 2 ... Liquid-impermeable back sheet, 3 ... Liquid-permeable surface sheet, 4 ... Absorber, 5 ... Crepe paper, 6 ... Absorber unit, 7 ... Heat-fusible nonwoven fabric, 8 ... Wave Processing roll, 9 ... anvil roll

Claims (8)

In the absorbent article in which the absorbent body is interposed between the liquid-permeable surface sheet and the liquid-impermeable back sheet,
The absorbent body is an absorbent body formed in the form of a sheet mainly composed of pulp and a highly water-absorbent resin, and a heat-fusible nonwoven fabric made of chemical fibers is laminated on the upper and lower surfaces or the upper surface of the absorbent body. In the region including the body fluid discharge site, a wave-like process in which concave portions and convex portions continue along the longitudinal direction of the absorbent article is applied together with the heat-fusible nonwoven fabric, and the wave-like processed region is measured by a KES compression tester. An absorbent article having a WC value (compression energy value) of 0.25 to 1.5 gf · cm / cm ² . In the absorbent article in which the absorbent body is interposed between the liquid-permeable surface sheet and the liquid-impermeable back sheet,
The absorbent body is an absorbent body formed in the form of a sheet mainly composed of pulp, chemical fiber and highly water-absorbent resin, and a heat-fusible nonwoven fabric made of chemical fibers is laminated on the upper and lower surfaces or upper surface of the absorbent body. In addition, a wave-like process in which a concave part and a convex part continue along the longitudinal direction of the absorbent article is applied to an area including at least a body fluid discharge site together with the heat-fusible nonwoven fabric , and KES compression of the wave-like processed area An absorbent article having a WC value (compression energy value) measured by a testing machine of 0.25 to 1.5 gf · cm / cm ² . The absorbent article of claim 2 Symbol placement content of the chemical fiber is 5 to 30%. The absorbent article according to any one of claims 1 to 3, wherein an apparent thickness of the wavy processed region of the absorber is 0.5 to 3.0 mm. The thickness of the absorber before the corrugated processing is 0.3 to 2.0 mm, and the corrugated processing is performed so that the apparent thickness after the corrugated processing is 1.6 to 10 times the thickness of the absorber before the corrugated processing. The absorbent article according to any one of claims 1 to 4 . In the wavy processed region of the absorber, the absorber thickness of the recesses and the projections is set to 0.3 to 2.0 mm, and the absorber thickness of the connecting portion connecting the recesses and the projections is 0.1 to 1 mm. The absorbent article according to any one of claims 1 to 5 , wherein the absorbent article is 8 mm, and the corrugated processing is performed so that the absorber thickness of the connecting portion is smaller than the absorber thickness of the concave and convex portions. The absorbent article according to any one of claims 1 to 6 , wherein an interval between the concave portions or the convex portions is 1.0 to 10 mm. The absorptive article according to any one of claims 1 to 7 whose content rate of said superabsorbent resin is 10 to 60%.

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