JP4392936B2 - Sanitary napkin - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an absorbent article excellent in fit and liquid leakage prevention properties.
[0002]
[Prior art and problems to be solved by the invention]
An absorbent article has been proposed in which an elastic member is stretched and the surface of the absorbent article is formed into a convex shape by its contraction force to improve the fit of the wearer to the body. For example, in Japanese Patent Publication No. 9-507033, an elastic member that is stretched in the width direction of the napkin is fixed to the non-skin contact surface side of the absorbent core in the sanitary napkin, and the napkin is contracted by contraction of the elastic member. A technique in which the surface has a convex shape is disclosed. In this napkin, a convex shape is formed only by the absorbent core. In order for the absorbent core itself to stably maintain the convex shape against the movement of the wearer, it is necessary to increase the rigidity of the absorbent core. However, if the rigidity is too high, the followability of the absorbent core to the wearer's body is deteriorated, and the fit is deteriorated. That is, keeping the convex shape stable with the absorbent core itself and improving the followability to the wearer's body are contradictory events.
[0003]
In JP-A-11-313851, a backing sheet having a higher bending rigidity than the liquid absorbent core is disposed on the non-skin contact surface side of the liquid absorbent core, and the backing sheet and the elastic member are combined. A sanitary napkin in which an inverted V-shaped space is formed inside the absorbent article is disclosed. The backing sheet is made of a sheet material such as a non-woven fabric, a plastic film, or an apertured plastic film, and has higher rigidity than the liquid-absorbent core. Therefore, the space can be formed by using the backing sheet, but at the same time, the high rigidity also causes a decrease in the flexibility and flexibility of the sheet. As a result, a gap is likely to be formed between the wearer's excretory part and the napkin, or the wearing feeling of the napkin is likely to deteriorate.
[0004]
Therefore, an object of this invention is to provide the absorbent article which always fits a excretion part with respect to a wearer's movement and can prevent a liquid leak effectively.
[0005]
[Means for Solving the Problems]
The present invention relates to a sanitary napkin having a liquid-permeable surface layer, a liquid-impermeable back layer, and a liquid-retaining absorbent layer interposed between the surface layer and the back layer.
A bulge-forming elastic member in which a bulge-forming sheet having bending recovery properties is disposed between the absorbent layer and the back surface layer, and both side portions of the bulge-forming sheet are stretched in the width direction. The raised portion forming sheet is raised to the surface layer side in a contracted state of the raised portion forming elastic member, and a convex raised portion is formed at a substantially central portion in the width direction of the sanitary napkin. ,
A plurality of flexible shafts for bending are formed along the longitudinal direction of the raised portion forming sheet in the raised portion forming sheet,
Wherein the raised portion forming sheet comprises a homogenous or two sheets of different and a Do that nonwoven fabric or foam of a thermoplastic resin, wherein the flexible shaft has the raised portion forming sheet for folding Are embossed so as to be formed in a plurality along the longitudinal direction of the two sheets, the two sheets are joined together by a large number of close contact portions to form the flexible shaft, and both are disposed between the close contact portions. There are non-adhered portions that are spaced apart, and the basis weight of the raised portion forming sheet is 30 to 500 g / cm ² ,
Further, a leak-proof groove having a closed structure in which the surface layer, the absorbent layer, the raised portion forming sheet, and the raised portion forming elastic member are integrally consolidated around the raised portion so as to absorb liquid. Is formed,
The leak-proof groove having a closed structure includes a substantially semicircular forward groove, a central groove curved in the direction of the center line along the longitudinal direction of the sanitary napkin, and an elongated ellipse cut at a short diameter portion. It is composed of a rear groove of the shape,
The thickness T at the position of the raised portion is 5 to 20 mm under a load of 490 Pa and 3 to 10 mm under a load of 4903 Pa, and the ratio between the thickness under the load of 490 Pa and the thickness under the load of 4903 Pa (the former / the latter) is 1. The above-mentioned object is achieved by providing a sanitary napkin that is .5-4.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 is a plan view of a sanitary napkin as an embodiment of the absorbent article of the present invention as viewed from the top sheet side, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. It is shown.
[0007]
A sanitary napkin 1 shown in FIG. 1 has a vertically long shape, a top sheet 2 constituting a liquid-permeable surface layer, a back sheet 3 constituting a liquid-impermeable back layer, and a top sheet 2 and a back. A liquid-retaining absorbent layer 4 interposed between the sheet 3 and the sheet 3 is provided. Adhesive layers 9 and 9 for fixing the napkin 1 to the wearer's clothes are formed on the outer surface of the back sheet 3. As the above members, the same members as those used in conventional napkins can be used.
[0008]
Between the absorption layer 4 and the back sheet 3, a rectangular raised portion forming sheet 5 is disposed. The raised portion forming sheet 5 is arranged at a position biased forward from the longitudinal central portion of the napkin 1. The raised portion forming sheet 5 is in contact with the lower surface of the absorbent layer 4, and is intermittently bonded and fixed to the lower surface of the absorbent layer 4. The left and right side portions on the lower surface of the raised portion forming sheet 5 are joined and fixed to the left and right side portions on the upper surface of the raised portion forming elastic member 6 made of a rectangular sheet. The left and right side portions on the lower surface of the raised portion forming elastic member 6 are respectively bonded and fixed to the upper surface of the back sheet 3. This joining position is substantially opposite to the joining position between the raised portion forming sheet 5 and the raised portion forming elastic member 6. The raised portion forming elastic member 6 is bonded and fixed to the raised portion forming sheet 5 in a state of being stretched in the width direction. The raised portion forming elastic member 6 is bonded and fixed to the back sheet 3 in its free state (relaxed state). Furthermore, in the joining position of the raised portion forming sheet 5 and the raised portion forming elastic member 6, the absorbent layer 4 and the top sheet 2 are integrally joined and fixed together with these members and are consolidated. And in the napkin 1 of this embodiment, in the free state (relaxed state), the protruding portion forming elastic member 6 is in a contracted state, and the protruding portion forming sheet 5 is raised on the top sheet 2 side. . As a result, the convex raised portion 7 is formed at a position that is substantially centered in the width direction of the napkin 1 and is displaced forward from the center portion in the longitudinal direction.
[0009]
The shape of the raised portion 7 is not particularly limited as long as it can fit the wearer's excretory portion, and examples thereof include an inverted U shape and an inverted V shape.
[0010]
The ridges forming sheet 5, may also be stably hold the convex shape of the raised portion 7, if example embodiment, nonwoven fabric or foam, etc. made of a thermoplastic resin. The nonwoven fabric is composed of, for example, fibers made of synthetic resin such as polyethylene, polypropylene, polyester, nylon, polyurethane, and core-sheath type or side-by-side type composite fiber made of a combination of these resins. The The foam is composed of polyethylene, vinyl acetate, polyurethane, polybutadiene, or the like.
[0011]
The raised portion forming sheet 5 preferably has appropriate rigidity, bending recovery and flexibility. As a method for imparting such characteristics to the raised portion forming sheet 5, it is only necessary to partially heat-compress the nonwoven fabric or foam formed of the above-described resin using hot embossing or the like. In particular, as the flexible shaft for folding are formed along the longitudinal direction of the ridge forming sheet 5, to facilities the thermal compression molding.
[0012]
Examples of the heat compression molding pattern include a linear pattern shown in FIG. 3A and a wavy pattern shown in FIG.
[0013]
In particular, as shown in FIG. 2, the raised portion forming sheet 5 is composed of two sheets 5a and 5b of the same kind or different kinds from the point that rigidity, bending recovery and flexibility are further improved . A sheet is used in which both sheets 5a and 5b are joined together by a large number of contact portions 51, and there is a non-contact portion 52 in which the both portions are separated from each other . Such a raised portion forming sheet 5 can be manufactured by, for example, steel match embossing. Further, in the raised portion forming sheet 5 shown in FIG. 2, these sheets and different types of sheets are interposed between the sheets 5 a and 5 b, and the three portions are in close contact with each other in the close contact portion 51 to be in a consolidated state. In the non-contact portion 52, it is also preferable to use a sheet in which the three members are in an unconsolidated state.
[0014]
As the raised portion forming sheet 5 having an appropriate rigidity, bending recovery property and flexibility, in addition to the above, a core-sheath type or a side-by-side type composite crimped two-dimensionally or three-dimensionally A suction heat bond nonwoven fabric formed by depositing fibers by the airlaid method to form a fiber web and fusing the entanglement points of the constituent fibers in the fiber web with hot air is also preferably used. The composite fiber constituting the suction heat bond nonwoven fabric is preferably a short fiber of about 5 to 15 mm.
[0015]
Ridge forming sheet 5 is held in the convex shape of the raised portion 7, and from the viewpoint of fit improvement ridges 7 to the wearer's body, a basis weight of 30 to 500 g / m ^2, preferably 50 to 300 g / m ² . Further, the bulging portion forming sheet 5 has a thickness of 0.3 to 5 mm, particularly 0.5 to 3 mm under a load of 490 Pa (5 gf / cm ² ). 1 is preferable in terms of preventing a sense of incongruity and flexibility and flexibility of the raised portion 7.
[0016]
The raised portion forming sheet 5 has a flexural rigidity of 2 × 10 ^{−3 to} 5 × 10 ⁻² gf · cm ² / cm, particularly 3 × 10 ⁻³ to 2 × 10 ⁻² gf · cm ² / cm. However, it is preferable in terms of stable formation of the raised portion 7, prevention of discomfort of the napkin 1 during wearing, flexibility and flexibility of the raised portion 7, and followability of the napkin 1 during wearing to the body.
[0017]
Further, the bulging portion forming sheet 5 has a bending recovery force of 1 × 10 ^{−3 to} 2.5 × 10 ⁻² gf · cm / cm, particularly 2 × 10 ⁻³ to 2 × 10 ⁻² gf · cm. / Cm is a point that the followability to the body is good when compression is applied from the width direction of the napkin 1 due to the movement of the wearer during walking or the like, and the napkin 1 being worn This is preferable from the viewpoint of preventing a sense of discomfort.
[0018]
The bending stiffness and the bending recovery force are measured as follows. For measurement, KES-FB2 (trade name) manufactured by Kato Tech is used. The protruding portion forming sheet 5 is cut into a length of 20 mm in a direction corresponding to the longitudinal direction of the absorbent article and 40 mm in a direction corresponding to the width direction of the absorbent article to obtain a measurement sample. Fix both sides of the measurement sample in the longitudinal direction (20 mm) to the chuck (distance between chucks is about 1 cm), and bend and deform to a curvature of 2.5 cm ^-1 with a curvature acceleration (bending deformation speed) of 0.5 cm ^-1 / sec. After that, restore the original state at the same speed. Bending required to obtain a bending moment M1 at a curvature of 0.5 cm ⁻¹ and a bending moment M2 at a curvature of 1.5 cm ^{−1 and} to deform from a curvature of 0.5 cm ⁻¹ to a curvature of 1.5 cm ⁻¹ during bending deformation. A moment is calculated | required from the following formula | equation (1), and this value is made into bending rigidity.
Flexural rigidity = M2-M1 (1)
Bending resilience is measured as follows. At the bending stiffness and the same measurement method, after bending deformation of the measurement sample to the curvature 2.5 cm ^-1, at the time of recovery in the process of restoring the original state to the curvature 1.5 cm ^-1 bending recovery moment M3 Ask for. This value is taken as the bending resilience.
[0019]
The raised portion forming elastic member 6 is made of a stretchable material. Examples of the material include natural rubber, polybutadiene, polyurethane, styrene-butadiene copolymer, styrene-isoprene copolymer, ethylene-α olefin copolymer such as ethylene and 1-octene copolymer, ethylene and acrylic acid. Examples thereof include a copolymer with ethyl.
[0020]
The raised portion forming elastic member 6 may be a film, a nonwoven fabric, a woven fabric, or the like made of the above material. Further, a plurality of filamentous bodies or narrow strips made of the material may be arranged in parallel with the width direction of the napkin 1 with a predetermined interval or without any interval.
[0021]
The raised portion forming elastic member 6 and the raised portion forming sheet 5 are bonded and fixed to each other at positions on both sides of the both, and are not fixed at other positions. The fixed distance between the raised portion forming elastic member 6 and the raised portion forming sheet 5 is 15 to 70 mm, particularly 30 to 60 mm, at the maximum length when the raised portion forming elastic member 6 is extended. This is preferable in that a raised portion 7 having a height high enough to properly fit the excretory portion is formed. The maximum length is an interval at which the bulge forming elastic member 6 is fixed to the bulge forming sheet 5, and is not a distance in a state in which the bulge forming elastic member 6 is contracted, but the bulge forming elastic member 6 is stretched and raised. This means a fixing interval when fixing to the part forming sheet 5.
[0022]
As a method for fixing the raised portion forming elastic member 6 and the raised portion forming sheet 5, in addition to joining using a hot melt adhesive, ultrasonic sealing, heat sealing, and the like can be given.
[0023]
Particularly preferably, the top sheet 2, the absorbent layer 4, the raised portion forming sheet 5 and the raised portion forming elastic member 6 are integrally joined and fixed together by hot embossing at the same time as forming a leakage prevention groove to be described later. From the point of simplification of the manufacturing process, it is preferable. At the same time, as shown in FIG. 2, the left and right side portions of the raised portion forming elastic member 6 are bonded and fixed to the backsheet 3 by hot melt adhesives 8 and 8. Moreover, the adhesive layers 9 and 9 are formed on the outer surface of the back sheet 3 as described above. The pressure-sensitive adhesive layer 9 has a strip shape extending in the longitudinal direction of the napkin 1 and is formed in two. It is preferable that the adhesive layers 9 and 9 are not provided in the center part of the width direction of the napkin 1 in which the top part of a protruding part is located. The width of the area where the pressure-sensitive adhesive layer is not formed in the center of the napkin 1 in the width direction, that is, the distance between the widthwise inner edges of the pressure-sensitive adhesive layers 9 and 9 is preferably 5 to 40 mm, particularly preferably 10 to 25 mm. . By forming the raised portion forming elastic member 6 in the joined state and the formation pattern of the pressure-sensitive adhesive layers 9 and 9 in this manner, the raised portion 7 having a height sufficient to fit the wearer's excretory portion is formed. In addition, the followability of the raised portion 7 becomes good both when worn and when the wearer operates.
[0024]
As shown in FIGS. 1 and 2, a leak-proof groove 10 capable of absorbing liquid, which is formed by compacting the constituent members, is formed on the top sheet 1 side of the napkin 1. The leak-proof groove 10 includes a substantially semicircular forward groove 10a, a central groove 10b having a shape curved in the direction of the center line along the longitudinal direction of the napkin 1, and a rear side of a shape obtained by cutting an elongated ellipse at a short diameter portion. It is comprised from the groove | channel 10c. And these groove | channels continue, and surround the circumference | surroundings of the protruding part 7 over the perimeter, and it has a closed structure. As used herein, “around the ridge” means at least a partial region around the ridge. Even if the leak-proof groove 10 is formed around the raised portion 7, even if the absorption layer 4 in the raised portion 7 absorbs a larger amount than the limit amount, the liquid flows out along the surface of the raised portion 7. The leaked liquid is reliably absorbed by the leak-proof groove 10. As a result, liquid leakage is extremely effectively prevented. In addition, by forming the leak-proof groove 10 around the raised portion 7, the flexibility in the leak-proof groove 10 portion is higher than the surrounding portions, and the napkin 1 is in the leak-proof groove 10 portion. It becomes easy to deform along the shape of the body. As a result, the napkin 1 is more easily fitted to the body from the raised portion 7 located at the center of the napkin 1 to both side portions, and the deformation followability of the napkin 1 is further improved. Therefore, it becomes a form more difficult to leak with respect to a wearer's operation, and a synergistic effect with the raised portion 7 is obtained. A closed structure that surrounds the entire periphery of the raised portion 7 as in the present embodiment is more preferable from the viewpoint of preventing leakage.
[0025]
In particular, as shown in FIG. 1, the high-pressure densified regions 11 and the low-pressure densified regions 12 are alternately formed in the leak-proof groove 10, thereby absorbing liquid in the leak-proof groove 10. Will improve.
[0026]
Although the depth of the leak-proof groove 10 is related to the thickness of the absorption layer 4, the distance from the upper surface portion to the lower surface portion of the groove is 1 mm or more, particularly 2 mm to 10 mm, is transmitted through the surface of the raised portion 7. From the viewpoint of the damming effect of the liquid that flows out. For the same reason, the width of the leak-proof groove 10 is preferably 1 mm or more, particularly 1.5 to 5 mm.
[0027]
As described above, the leak-proof groove 10 is formed by integrally compacting the top sheet 2, the absorption layer 4, the raised portion forming sheet 5, and the raised portion forming elastic member 6 by hot embossing .
[0028]
Napkin 1 has a thickness T (see FIG. 2) at the position of the ridge 7 is a 5~20mm in 490 Pa (5 gf / cm ²⁾ under a load, preferably Ru 7~15mm der (hereinafter, under the load ) that the thickness T ₅ at. The load under 490 Pa corresponds to the load applied to the absorbent article when the wearer does not move while standing with the absorbent article, and the thickness T _{5 at} this time is within the above range. A raised portion 7 that is high enough to fit properly to the excretory portion is formed.
[0029]
The napkin 1 has a thickness at the position of the raised portion 7 is 3~10mm in 4903Pa (50g / cm ²⁾ under a load, preferably Ru 4~8mm der (hereinafter, the thickness of the under this load T ₅₀ Called). Under the load of 4903 Pa, it corresponds to the load applied to the absorbent article when the wearer is sitting or running, and the thickness T _{50 at} this time is within the above range, so that the wear is similar to the reason described above regarding T _5. A raised portion 7 that is high enough to fit properly to the person's excretory portion is formed.
[0030]
Further napkin 1, the ratio of T ₅ and T _50, i.e., the value of T ₅ / T ₅₀ is 1.5 to 4, Ru preferably 2-3.5 der. The value of T ₅ / T ₅₀ is a measure of the compression recovery property at the raised portion 7 of the napkin 1, and the value of T ₅ / T ₅₀ falls within the above range, resulting in the movement of the wearer. The deformation followability of the napkin 1 with respect to the change in the mounting pressure becomes sufficient, and the fit is sufficiently high.
[0031]
T ₅ and T ₅₀ are measured for a 1 cm × 1 cm region at the position of the raised portion 7 of the napkin 1.
[0032]
The present invention is not limited to the embodiment. For example, in the above embodiment, the leak-proof groove 10 is formed around the entire circumference of the raised portion 7, but instead, for example, a pair of leak-proof grooves 10 are formed only on both sides of the raised portion 7. (That is, only the central groove 10b may be formed).
[0033]
In the above-described embodiment, the raised portion forming elastic member 6 is bonded and fixed to the back sheet 3 in its free state (relaxed state), but instead, the raised portion forming elastic member 6 is extended in the extended state. And may be fixed. Also by this, the raised portion forming sheet 5 is raised to the top sheet 2 side by the contraction of the raised portion forming elastic member 6, and the raised portion 7 is formed.
[0034]
Further, the absorbent article of the present invention can be similarly applied to a sanitary napkin, a cage sheet, an incontinence pad, and the like.
[0035]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the absorbent article which always fits an excretion part with respect to a wearer's movement and can prevent a liquid leak effectively is provided.
[Brief description of the drawings]
FIG. 1 is a plan view of a sanitary napkin as an embodiment of the absorbent article of the present invention as viewed from the top sheet side.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a schematic view showing a raised portion forming sheet used in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sanitary napkin 2 Top sheet 3 Back sheet 4 Absorbing layer 5 Raised part forming sheet 6 Raised part forming elastic member 7 Raised part 10 Leak-proof groove

Claims (1)

In a sanitary napkin having a liquid-permeable surface layer, a liquid-impermeable back layer, and a liquid-retaining absorbent layer interposed between the surface layer and the back layer,
A bulge-forming elastic member in which a bulge-forming sheet having bending recovery properties is disposed between the absorbent layer and the back surface layer, and both side portions of the bulge-forming sheet are stretched in the width direction. The raised portion forming sheet is raised to the surface layer side in a contracted state of the raised portion forming elastic member, and a convex raised portion is formed at a substantially central portion in the width direction of the sanitary napkin. ,
A plurality of flexible shafts for bending are formed along the longitudinal direction of the raised portion forming sheet in the raised portion forming sheet,
Wherein the raised portion forming sheet comprises a homogenous or two sheets of different and a Do that nonwoven fabric or foam of a thermoplastic resin, wherein the flexible shaft has the raised portion forming sheet for folding Are embossed so as to be formed in a plurality along the longitudinal direction of the two sheets, the two sheets are joined together by a large number of close contact portions to form the flexible shaft, and both are disposed between the close contact portions. There are non-adhered portions that are spaced apart, and the basis weight of the raised portion forming sheet is 30 to 500 g / cm ² ,
Further, a leak-proof groove having a closed structure in which the surface layer, the absorbent layer, the raised portion forming sheet, and the raised portion forming elastic member are integrally consolidated around the raised portion so as to absorb liquid. Is formed,
The leak-proof groove having a closed structure includes a substantially semicircular forward groove, a central groove curved in the direction of the center line along the longitudinal direction of the sanitary napkin, and an elongated ellipse cut at a short diameter portion. It is composed of a rear groove of the shape,
The thickness T at the position of the raised portion is 5 to 20 mm under a load of 490 Pa and 3 to 10 mm under a load of 4903 Pa, and the ratio between the thickness under the load of 490 Pa and the thickness under the load of 4903 Pa (the former / the latter) is 1. A sanitary napkin that is 5-4.

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