JP6147527B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as urine collection pads, disposable diapers, light incontinence pads, and liners.

With the progress of an aging society, the demand for disposable absorbent articles for adults is increasing. In particular, it is desirable that the absorbent article for elderly people whose excretion cannot be controlled by themselves and who cannot stand on their own is free from leakage or rash. Therefore, the absorption performance (absorption of liquid excretion such as urine) Various types having improved amounts, absorption speeds, and liquid return amounts have been developed.
Moreover, since an absorbent article becomes disposable, weight reduction is requested | required from ecological viewpoints, such as a resource saving and the reduction | decrease of the waste after use.
For this reason, in a vertically long disposable diaper, a technology has been developed that increases the amount of absorption on both sides in the width direction than the central portion of the absorbent layer, suppresses manufacturing costs, and improves leakage prevention and fit. (See patent literature).

Japanese Patent Laid-Open No. 2003-164477

By the way, when there is urination in the central portion of the absorbent layer, urine is absorbed and diffused concentrically in the conventional absorbent article. There is a problem that the absorption capacity of the absorption layer in the direction is not fully utilized. Moreover, the conventional absorbent article has a problem that the fit to the body at the time of wearing is not sufficient, and leakage is likely to occur.
Further, absorbent articles such as urine pads are sold in a state of being folded and packaged in three in the longitudinal direction and in a direction perpendicular to the longitudinal direction. However, if a relatively thick absorbent layer is folded, the fold portion is compressed. Easy to feel hard.
Therefore, an object of this invention is to provide the absorbent article which improved the absorption performance and fitting property, implement | achieving weight reduction and low cost.

As a result of studies by the present inventors, the absorption layer has an upper layer and a lower layer, and by making the upper layer narrower than the lower layer, diffusion in the width direction of liquid such as urine absorbed from the upper layer side is regulated. It has been found that it spreads and spreads in a long oval shape in the longitudinal direction. Further, by providing the embossment with a concave shape in the absorption layer, the diffusion of the liquid in the longitudinal direction further proceeds along the embossment.
In order to solve the above problems, an absorbent article according to the present invention includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent layer disposed between the top sheet and the back sheet. The absorbent layer has an upper layer on the top sheet side and a lower layer on the back sheet side, the upper layer is narrower than the lower layer, and the thickness of the upper layer is 30% or more and 70% or less of the total thickness of the upper layer and the lower layer, as viewed from the upper layer side, the concave first emboss reaching from the upper layer to the lower layer, and the protrusion protruding in the width direction from the upper layer lower only shallow concave second embossed formed than the first embossed is formed, the first embossed and the second embossing is a plurality of linear consecutive widthwise side edges of the upper layer 0-10mm outward from Is folded longitudinally position.
According to this absorbent article, by making the upper layer narrower than the lower layer, the diffusion in the width direction of liquid such as urine absorbed from the upper layer side is regulated, and the diffusion in the longitudinal direction is promoted. , Spread in a long oval shape in the longitudinal direction. Thereby, the absorption capacity of the absorption layer can be used without waste, and the entire amount of the absorption layer can be reduced accordingly, so that weight reduction and low cost can be realized without impairing the absorption performance.
In addition, since the upper layer is narrower than the lower layer, the center of the absorbent layer in the width direction is thick and both ends are thin, so that it is excellent in fit to the body at the time of wearing and hardly leaks.
In addition, since the portion close to the side edge in the width direction is folded, the crease is not noticeable when the fold is expanded, and a smooth shape is obtained without being squared. In particular, since the absorbent article is usually folded in three in the longitudinal direction and then folded in a direction perpendicular to the longitudinal direction and sold in a packaged state, it is advantageous that the folds are not noticeable.

  When the width of the upper layer is 30 to 80% of the width of the lower layer, liquid such as urine is more likely to diffuse in the longitudinal direction.

It is preferable that the width of the upper layer is 20 to 70% with respect to the maximum width of the absorbent article.
It is preferable that the upper layer and the lower layer include fluff pulp and a superabsorbent resin, and the weight ratio of the superabsorbent resin in the upper layer is larger than the weight ratio of the absorbent resin in the lower layer.
It is preferable that a hydrophilic nonwoven fabric that improves liquid diffusibility is provided between the top sheet and the upper layer.

  According to the present invention, an absorbent article with improved absorption performance and fit can be obtained while realizing weight reduction and low cost.

It is a perspective view which shows the external appearance of the absorbent article which concerns on embodiment of this invention. It is sectional drawing which follows the AA line of FIG. It is a top view of an absorption layer.

Embodiments of the present invention will be described below. FIG. 1 is a perspective view showing an appearance of an absorbent article 200 according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG.
As shown in FIGS. 1 and 2, an absorbent article 200 according to an embodiment of the present invention has an elongated piece shape, and a liquid-permeable top sheet 202 that forms a body contact side surface (upper surface in FIG. 2). A liquid-impermeable back sheet 204 and a top sheet 202 and an absorbent layer 210 disposed between the back sheets 204 are configured. The absorbent layer 210 is formed by laminating an upper layer 211 on the top sheet 202 side and a lower layer 212 on the back sheet 204 side, and the width W1 of the upper layer 211 is narrower than the width W2 of the lower layer. Further, a hydrophilic nonwoven fabric 208 that improves liquid diffusibility is disposed between the top sheet 202 and the upper layer 211.
The absorbent article 200 is passed in the longitudinal direction before and after the crotch of the user, and is attached so that the top sheet 202 touches the user's skin (crotch), and both sides of the absorbent article 200 are three-dimensional gathers. Standing up as 206 prevents side leakage of urine and the like. Further, the absorbent article 200 has a slightly narrower width near the center of the top sheet 202 so that it can be easily attached to the crotch.

The absorption layer 210 has an upper layer 211 and a lower layer 212, and by making the upper layer 211 narrower than the lower layer 212, the diffusion of liquid such as urine absorbed from the upper layer 211 side in the width direction is restricted, and Since diffusion in the direction is promoted, it spreads and spreads in the shape of an ellipse that is long in the longitudinal direction. As a result, the absorption capacity of the absorption layer 210 can be used without waste, and the entire amount of the absorption layer 210 can be reduced accordingly, so that weight reduction and low cost can be realized without impairing the absorption performance.
In addition, since the upper layer 211 is narrower than the lower layer 212, the absorption layer 210 has a thick center in the width direction and thin ends, so that it is excellent in fit to the body when worn and is less likely to leak.
In addition, when the thickness of the upper layer 211 is t1, and the thickness of the lower layer 212 is t2, the thickness t1 is preferably 30% or more and 70% or less of the total thickness (t1 + t2), and more preferably 30 to 50%. . Accordingly, only one of the upper layer 211 and the lower layer 212 does not exhibit excessive absorption capability, and liquid such as urine is easily diffused in an elliptical shape that is long in the longitudinal direction.

  In order to fully exhibit the above effects, the width W1 of the upper layer 211 is preferably 30 to 80%, more preferably 40 to 70%, and more preferably 45 to 65% of the width W2 of the lower layer 212. Most preferred. When W1 is less than 30% of W2, the absorption capacity of the upper layer 211 decreases, and liquid such as urine tends to hardly diffuse in the longitudinal direction. When W1 exceeds 80% of W2, the dimensional difference in the width direction between the upper layer 211 and the lower layer 212 becomes small, and it tends to be difficult for liquid such as urine to diffuse in the longitudinal direction.

Further, the width W1 of the upper layer 211 is preferably 20 to 70%, more preferably 30 to 60% with respect to the maximum width W3 of the absorbent article 200.
The total thickness of the absorbent layer 210 is preferably 2 to 8 mm.

As shown in FIGS. 2 and 3, when viewed from the upper layer 211 side, the first emboss is formed only on the concave first emboss 211 e reaching from the upper layer 211 to the lower layer 212 and the lower layer 212 protruding in the width direction from the upper layer 211. A concave second emboss 212e shallower than 211e is formed.
The first embossed 211e and the second embossed 212e are provided in the absorption layer 210, and the first embossed 211e becomes strong and deep embossed, so that the diffusion of the liquid in the longitudinal direction further proceeds along the first embossed 211e.
The planar pattern of the first embossed 211e and the second embossed 212e can be, for example, a plurality of continuous lines or a combination of a plurality of lines. Specifically, straight lines, curved lines, grids, meshes, etc. Any known one can be used.

Both the upper layer 211 and the lower layer 212 preferably include fluff pulp and a superabsorbent resin (superabsorbent polymer; SAP). In addition, the weight ratio S1 of the superabsorbent resin in the upper layer 211 is preferably larger than the weight ratio S2 of the superabsorbent resin in the lower layer 212. By setting S1> S2, the absorption performance of the upper layer 211 is increased, and the liquid such as urine is easily diffused in the longitudinal direction in the upper layer 211.
As the SAP, either a crushing type or a pearl type (obtained by a reverse phase suspension polymerization method) can be selected.
Wood pulp such as softwood kraft pulp and hardwood kraft pulp can be mainly used as the fluff pulp. In addition, non-wood pulp such as cotton linter or heat-synthetic synthetic fiber can be appropriately mixed with fluff pulp.
Superabsorbent resin (SAP) is a polymer having a network-like molecular structure, which absorbs water several hundred times its own weight, swells in a gel state, and retains the water. SAP has a synthetic polymer system and a natural product-derived system. As the synthetic polymer system, a polyacrylic acid system, a polysulfonic acid system, an acrylamide system, a polyvinyl alcohol system, etc. can be used. Although a system, a cellulose system, etc. can be utilized, these are not specifically limited but can be used suitably.

It is preferable that the absorbent article 200 is folded in the longitudinal direction (folded in three) at a position (fold line) F outside the width direction side edge portion 211s of the upper layer 211. In general, when a relatively thick absorbent layer is folded, the crease portion is likely to be compressed and hard to feel. To prevent becoming.
The position F is preferably 0 to 10 mm outward from the side edge portion 211s (corresponding to the distance G in FIG. 3). In this case, the portion close to the width direction side edge portion 211s is folded, so that when the fold is expanded, the crease is not conspicuous and becomes a smooth shape without being squared.
Normally, the absorbent article 200 is folded in three in the longitudinal direction, and then folded in a direction perpendicular to the longitudinal direction, and sold in a packaged state.

Next, other components of the absorbent article 200 will be described.
The top sheet 202 may be a liquid-permeable hydrophilic non-woven fabric, and is made of a fiber material that is soft to the touch and does not irritate the skin because it contacts the user's skin. The basis weight of the top sheet 202 is preferably 20 g / m ² or more. When the basis weight of the top sheet 202 is less than 20 g / m ² , the amount of liquid return increases, giving the wearer an unpleasant feeling and further causing a rash. As the top sheet 202, an air-through nonwoven fabric, a point bond nonwoven fabric, a spunbond nonwoven fabric, a spunlace nonwoven fabric, or the like made of a synthetic fiber such as polypropylene, polyethylene, or polyester can be used. In particular, an air-through nonwoven fabric with a small liquid return amount is suitable.
The back sheet 204 only needs to be formed from a liquid-impermeable material having a waterproof property so that liquid held in the absorbent layer 210 does not leak into the underwear, and is a thin plastic such as a breathable polyethylene film. Although it can be made into a film, a cross-like back sheet in which micro embossing is applied to the back sheet 204 or a non-woven fabric is laminated on the outside of the plastic film so that the sound that is rustled during wearing is difficult and soft is given. It can also be used.
Moreover, it is preferable to reduce stuffiness using a breathable film.

The hydrophilic non-woven fabric 208 is disposed under the top sheet 202 to promote diffusion of urine and filth, and can move the liquid to the absorption layer 210 over a wide range and efficiently absorb it. As the hydrophilic non-woven fabric 208, an air-through non-woven fabric, a point-bond non-woven fabric, a spun-bond non-woven fabric or the like made of a synthetic fiber such as polypropylene, polyethylene, or polyester having a thickness of 0.2 mm or more and a basis weight of 20 g / m ² or more can be used. In particular, an air-through nonwoven fabric with a small liquid return amount is suitable.
The three-dimensional gather 206 can be composed of a water-repellent nonwoven fabric such as a spunbond nonwoven fabric or a spunbond / meltblown composite material, and the basis weight thereof is not particularly limited.

Then, the absorbent layer 210 is sandwiched between the top sheet 202 and the back sheet 204, and further, a hydrophilic nonwoven fabric 208 and a three-dimensional gather 206 are appropriately disposed, and then the top sheet 202 and the back sheet 204 are hot-melt bonded over the entire circumference. The absorbent article 200 can be manufactured by fixing using an agent. Adhesives include synthetic rubbers such as styrene-butadiene-styrene copolymers and styrene-isoprene-styrene copolymers having a melting point of about 100 to 180 ° C .; or olefins such as ethylene-vinyl acetate copolymers Hot melt adhesives of the system can be used. Hot melt adhesive application methods include a curtain coating method in which a molten adhesive is applied in a non-contact manner from a nozzle, a spiral method, a slot method in which a contact method is applied, and any known method can be used. .
Further, by simultaneously embossing the absorbing layer 210 in which the upper layer 211 and the lower layer 212 are laminated, the first embossed 211e in the widthwise central portion (upper layer 211) having a large thickness is formed strong and deep, and both end portions having a small thickness. The second emboss 212e in the (lower layer 212) is weak and shallow.

  It goes without saying that the present invention is not limited to the above-described embodiments, and extends to various modifications and equivalents included in the spirit and scope of the present invention.

<Manufacture of absorbent articles>
The absorbent article 200 shown in FIGS. 1 to 3 was manufactured. The top sheet 202 is a 20 g / m ² air-through nonwoven fabric, the back sheet 204 is a 20 g / m ² non-breathable polyethylene sheet, and the hydrophilic nonwoven fabric (Example 2, Comparative Examples 3 and 4 only) is 20 g / m. ² air-through nonwoven fabric.
The maximum length in the longitudinal direction of the absorbent article 200 was 480 mm, and the length in the longitudinal direction of the upper layer 211 and the lower layer 212 was 420 mm. Other characteristics such as dimensions are shown in Table 1.
The “normal product” was obtained by setting the SAP weight of the upper layer 211 to 1.5 g and the SAP weight of the lower layer 212 to 2.0 g. The SAP weight of the upper layer 211 was increased to 2.0 g, and the SAP weight of the lower layer 212 was increased to 5.0 g. Moreover, the embossing of the concave shape was given to the absorption layer 210 after laminating | stacking the upper layer 211 and the lower layer 212. FIG.
The following evaluation was performed about the obtained absorbent article 200 and each component.

Basis weight: measured based on JIS P8124.
Thickness: Measured using a thickness gauge (a dial thickness gauge “PEACOCK” manufactured by Ozaki Seisakusho). The measurement conditions were a measurement load of 250 gf and a probe diameter of 30 mm. A sample was placed between the probe and the measurement table, and the gauge was read when the probe was lowered at a speed of 1 mm or less per second.
Specific volume: The thickness was divided by the basis weight and expressed as a volume cm ³ per unit g.
The basis weight, thickness, and specific volume were measured after maintaining the equilibrium state under the temperature and humidity conditions (23 ± 1 ° C., 50 ± 2% RH) specified in JIS-P8111.

Absorption speed of the absorbent article: A cylindrical measuring jig having a bottom area of 16.8 cm ^{2 with} a weight of 755.6 g and a hole with an inner diameter of 19 mm in the center is placed on the center of the absorbent article 200, and the measuring jig 40 ml of physiological saline was injected from the upper hole. The time from when the physiological saline contacted the water absorbent article 200 until the physiological saline was completely sucked into the edge of the jig center hole was measured (first time). After 3 minutes, 40 ml of physiological saline is injected again, and the time until absorption is similarly measured (second time). After further 3 minutes, 40 ml of physiological saline is injected again and absorbed similarly. Was measured (the third time). In addition, the measurement of each absorption rate of the above-mentioned 1st time, 2nd time, and 3rd time was made into the average value of what was performed about all N = 3 samples. Moreover, the total value of each absorption rate of the 1st time-the 3rd time was also calculated. The above total value is preferably 90 to 210 seconds in the case of “normal products”, and preferably 60 to 150 seconds in the case of “high absorption products”.
Liquid return amount: Saline (300 ml for “normal product”, 450 ml for “high absorption product”) was injected into the center of the absorbent article 200, and after 10 minutes, the weight of the filter paper was measured in advance ( ADVANTEC No. 2 filter paper (diameter 55 mm) was placed at the center of the injection part, and a 687 g weight was placed on the filter paper (pressure: 35 g / cm ² ). One minute after placing the weight, the weight of the filter paper was measured, and the weight difference (g) of the filter paper before and after the test was defined as the liquid return amount. The liquid return amount was an average value of N = 3 samples. The amount of liquid return is preferably 0 to 0.6 g in the case of “normal product”, and preferably 0 to 0.3 g in the case of “high absorption product”.

Product cost: Per product of the absorbent article 200 of Example 1, the ratio of SAP, fluff, and the entire absorbent article is 1.00.
Diffusion distance at the time of water absorption: After fixing on the plane with the upper layer 211 side of the absorption layer 210 facing upward, 150 ml of 36 ° C. physiological saline at the center in the longitudinal direction and width direction of the upper layer 211 using a funnel Injected. And the diffusion distance of the salt solution from the center to the longitudinal direction and the width direction was measured over time.
The obtained results are shown in Table 1.

As is apparent from Table 1, the upper layer of the absorbing layer is made narrower than the lower layer, the thickness of the upper layer is 30% or more and 70% or less of the total thickness of the upper layer and the lower layer, and concave first embossments are formed on the upper layer and the lower layer. In the case of each Example in which the second emboss was formed, the absorption rate of the obtained absorbent article (meaning that the total value from the first to the third time is small) is high, the liquid return amount is small, and the absorption performance It was excellent.
In each of the examples, diffusion in the longitudinal direction of the absorption layer was promoted during water absorption, and diffused and spread in a long elliptical shape in the longitudinal direction.

On the other hand, in the case of Comparative Examples 1 and 3 in which the upper layer of the absorption layer has the same width as the lower layer and the thickness of the upper layer is less than 30% of the total thickness of the upper layer and the lower layer, the diffusibility in the longitudinal direction of the absorption layer upon water absorption Therefore, the absorption rate and liquid return amount of the obtained absorbent article were inferior to those of Examples 1 and 2, respectively. In the case of Comparative Examples 1 and 3, since the upper layer and the lower layer of the absorption layer of Examples 1 and 2 were made the same width, the product cost was the same as the corresponding example.
In the case of Comparative Examples 2 and 4 in which the upper layer of the absorbent layer has the same width as the lower layer and the second emboss is not formed, since the diffusibility in the longitudinal direction of the absorbent layer is poor at the time of water absorption, The absorption rate and liquid return amount were inferior to those of Examples 1 and 2, respectively. In the case of Comparative Examples 2 and 4, the basis weight (fluff weight) of the upper layer was increased as compared with Comparative Examples 1 and 3 in order to increase the absorption rate of the absorbent article. For this reason, compared with the corresponding Example, although the total value of each absorption rate of the 1st time-the 3rd time became equivalent, the product cost became high.

200 Absorbent article 202 Top sheet 204 Back sheet 208 Hydrophilic nonwoven fabric 210 Absorbing layer 211 Upper layer 211e First emboss 211s Side edges in the width direction of the upper layer 212 Lower layer 212e Second embossed t1 Upper layer thickness t2 Lower layer thickness W1 Upper layer Width W2 Lower layer width W3 Maximum width of absorbent article F Longitudinal crease

Claims (5)

An absorbent article having a liquid permeable top sheet, a liquid impermeable back sheet, and an absorbent layer disposed between the top sheet and the back sheet,
The absorbent layer has an upper layer on the topsheet side and a lower layer on the backsheet side, and the upper layer is narrower than the lower layer,
The thickness of the upper layer is 30% to 70% of the total thickness of the upper layer and the lower layer,
A concave first emboss formed from the upper layer to the lower layer as viewed from the upper layer side and a concave second emboss formed only in the lower layer protruding in the width direction from the upper layer and shallower than the first emboss are formed. And
The first embossed and the second embossing is a plurality of continuous linear,
An absorbent article that is folded in the longitudinal direction at a position of 0 to 10 mm outward from the widthwise side edge of the upper layer.   The absorbent article according to claim 1, wherein a width of the upper layer is 30 to 80% of a width of the lower layer. The absorbent article according to claim 1 or 2 , wherein a width of the upper layer is 20 to 70% with respect to a maximum width of the absorbent article. The upper layer and the lower layer include fluff pulp and a superabsorbent resin, and the weight ratio of the superabsorbent resin in the upper layer is greater than the weight ratio of the absorbent resin in the lower layer. Absorbent article according to crab. The absorbent article in any one of Claims 1-4 with which the hydrophilic nonwoven fabric which improves the diffusibility of a liquid is provided between the said top sheet and the said upper layer .

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