JP6224969B2 - Absorbent articles - Google Patents

Description

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

DESCRIPTION OF RELATED ART Conventionally, the absorbent article which provided the absorption layer between the liquid-permeable upper sheet and the liquid-impermeable back sheet, and has arrange | positioned the upper sheet side to the wearer's skin side is used widely. However, if the absorption amount of the absorption layer is insufficient, there is a problem that urine leaks to the outside.
Accordingly, various absorbent articles have been developed that can absorb urine and the like from both the front and back surfaces. For example, an absorbent article in which a nonwoven fabric is disposed on both sides of an absorbent layer has been developed (see Patent Document 1). In addition, an absorbent article has been developed in which absorbent bodies (absorbing layers) are disposed on both surfaces of a non-liquid-permeable sheet (see Patent Document 2).

Japanese Utility Model Publication No.2-130627 JP 2009-178235 A

By the way, if the absorbent article has a function capable of absorbing urine from both sides, depending on the wearer's incontinence state and incontinence pattern, etc., `` I want to absorb repeatedly '' or `` reverse after urination is reduced I want to stay comfortable. " Furthermore, as another request, "I want to transfer urine to the diaper that is used in layers (lower side) to increase the total amount of absorption", or "The lower diaper that absorbs as much as possible with the double-sided pad itself, I don't want to get dirty. "
However, since the absorbent capacity of the absorbent article is limited from the viewpoint of cost, it is difficult to satisfy all of the various demands described above.
Accordingly, an object of the present invention is to provide an absorbent article that can absorb urine and the like from both sides and that reduces the reversal after urination while increasing the amount of absorption.

In order to solve the above problems, an absorbent article of the present invention includes an absorbent layer, a liquid-permeable upper sheet that covers the upper surface of the absorbent layer, and a liquid-permeable lower sheet that covers the lower surface of the absorbent layer. And the hydrophilicity of the upper sheet is higher than the hydrophilicity of the lower sheet, the upper sheet and the lower sheet are both made of a nonwoven fabric imparted with hydrophilicity, and the hydrophilicity of the upper sheet is 10. 0 or more, the hydrophilicity of the lower sheet is 1.0 or more and less than 10.0 , and the difference in hydrophilicity between the upper sheet and the lower sheet is 3.0 or more .
According to this absorbent article, when the upper sheet is directed to the wearer's local side, the absorption rate of urine or the like absorbed into the absorbent layer through the upper sheet increases, and can be absorbed repeatedly. On the other hand, because the lower sheet has a low hydrophilicity, the amount of urine oozing out from the lower sheet is reduced, and when a disposable diaper is placed under the absorbent article (the lower sheet) The transition to can be reduced.
In addition, since the hydrophilicity of the upper sheet and the lower sheet is different, an effect opposite to that described above occurs when the front and back surfaces are changed. Specifically, when the lower sheet is directed to the wearer's skin side, reversal of urine and the like after absorption can be reduced, and the upper sheet on the back side has high hydrophilicity, so use in combination. Transfer of urine etc. to other disposable diapers (lower side) can be increased, and the total amount of absorption can be increased.
As described above, since different effects can be obtained by changing the front and back of the absorbent article, one absorbent article can be properly used according to the use situation, and two or more kinds of absorbent articles as in the past. It is no longer necessary to prepare for the daytime and nighttime, and it is possible to reduce the time and storage space for proper use.

  According to the present invention, it is possible to obtain an absorbent article that can absorb urine and the like from both sides and that reduces the amount of reversion after urination while increasing the amount of absorption.

It is a top view of an absorptive article concerning an embodiment of the present invention. It is sectional drawing which follows the AA line of FIG.

Embodiments of the present invention will be described below. FIG. 1 is a top view of an absorbent article 200 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG.
As shown in FIGS. 1 and 2, the absorbent article 200 has a substantially rectangular sheet shape, and includes an absorbent layer 210, a liquid-permeable upper sheet 202 </ b> A and a lower sheet 202 </ b> B that cover the upper and lower surfaces of the absorbent layer 210, respectively. Have The absorbent layer 210 has a rectangular shape, and the four opposing corners of the upper sheet 202A and the lower sheet 202B are fixed by a hot melt adhesive or the like over the entire circumference.

The absorbent layer 210 includes, for example, fluff pulp and a superabsorbent resin (superabsorbent polymer; SAP).
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 to use a sheet-like absorbent layer in which SAP is formed as a sheet as the absorbent layer 210 because the thickness is further reduced. The sheet-like absorbent layer is obtained by supporting SAP in a sheet form on a hydrophilic sheet such as a hydrophilic non-woven fabric or a pulp sheet, and various types are commercially available.
The sheet-like absorbent layer can be produced, for example, by fixing SAP with a hot melt adhesive between ^two hydrophilic sheets (each having a basis weight of 15 g / m ² or more).

In the present invention, the hydrophilicity of the upper sheet 202A is higher than the hydrophilicity of the lower sheet 202B. Accordingly, when the upper sheet 202A is directed to the wearer's local side, the absorption rate of urine or the like absorbed into the absorbent layer 210 through the upper sheet 202A is increased, and can be absorbed repeatedly. On the other hand, since the hydrophilicity of the lower sheet 202B on the back surface side is low, oozing of urine and the like from the lower sheet 202B is reduced, and when a paper diaper or the like is used under the absorbent article 200 (lower side) )) The transition to paper diapers can be reduced.
For example, it is suitable to use the upper sheet 202A having a high hydrophilicity toward the skin side of the wearer when the diaper can be changed every time urination is performed during the daytime or in a short time. This is because the urine absorption rate of the absorbent article 200 is fast and the urine transfer to the paper diaper used in combination is small, so that the urine absorbed by the absorbent article 200 stays in the absorbent article 200 and only the absorbent article 200 is removed. By exchanging, the disposable diaper can be used for a long time.

Further, since the hydrophilicity of the upper sheet 202A and the lower sheet 202B is different, the effect opposite to the above occurs when the front and back sides are changed. Specifically, when the lower sheet 202B is directed to the wearer's skin side, reversal of urine and the like after absorption can be reduced and the hydrophilicity of the upper sheet 202A on the back side is high, Transfer of urine or the like to other (diaper) disposable diapers is increased, and the total amount of absorption can be increased.
For example, if you want to avoid changing diapers over a long period of time, such as during nighttime use, if you use the lower hydrophilic sheet 202B with low hydrophilicity facing the skin side of the wearer, there will be little urine reversion after absorption, Since the shift to paper diapers to be used in combination increases and the total amount of absorption can be increased, it is suitable for use, for example, where diapers are not changed overnight.

  As described above, since different effects can be obtained by changing the front and back of the absorbent article 200, one absorbent article can be used properly according to the use situation, and two or more types of absorbent are used as in the past. It is not necessary to prepare articles and use them separately during the daytime and at night, and it is possible to reduce the time and storage space for proper use.

On the other hand, if the hydrophilicity of the upper sheet 202A and the lower sheet 202B is the same, the above difference in absorption characteristics cannot be obtained even if the front and back sides are changed. In addition, since the above-described absorption characteristics are hardly generated even when the hydrophilicity of the upper sheet 202A and the lower sheet 202B is too small, the difference in hydrophilicity between the upper sheet 202A and the lower sheet 202B is preferably 3.0 or more. And more preferably 5.0 or more.
Further, if the hydrophilicity of the upper sheet is not secured to some extent, it is difficult to obtain a desired absorption amount. Therefore, the hydrophilicity of the upper sheet 202A is preferably 10.0 or more, and preferably 15.0 to 30.0. Is more preferable. The hydrophilicity of the lower sheet 202B is preferably 1.0 or more and less than 10.0, and more preferably 2.0 to 8.0.
Moreover, it is preferable that both the upper sheet 202A and the lower sheet 202B are made of a nonwoven fabric imparted with hydrophilicity. When each sheet has such a configuration, the hydrophilicity can be adjusted by changing the type of oil agent (surfactant) for hydrophilic treatment of the raw material fiber (raw cotton) during the production of the nonwoven fabric.

The hydrophilicity of the upper sheet 202A and the lower sheet 202B is calculated based on the values of the following water permeability test and wet back test.
1. Water permeability test First, a sheet to be measured is cut to 50 × 50 mm to obtain a test piece. Next, a test piece is placed on 5 sheets of qualitative filter paper (# 2 (No.2): JIS P 3801 type 2) with a diameter of 55 mmφ, and an inner diameter of 20 mmφ and an outer diameter of 45 mmφ are used to suppress distortion of the filter paper. A weight (weight 10.2 g) is placed on the test piece. Then, 1 drop (0.05 mL) of physiological saline is dropped on the test piece from a height of 1 cm with a 10 mL measuring pipette, and it is confirmed whether the water drop permeates the test piece and is absorbed by the filter paper within 30 seconds. Specifically, if water droplets disappear from the surface of the test piece, it is determined that permeation and water absorption have occurred. In this way, when it is determined that water droplets have disappeared from the surface of the test piece, physiological saline is dropped again at the same position under the same conditions after 30 seconds from the first drop. Specifically, for example, when it is determined that the water droplet has disappeared 24 seconds after the dropping, the next dropping is performed 6 seconds after that. When dropping is repeated in this manner, the hydrophilicity of the test piece is lowered and the water repellent state is obtained. Then, when the physiological saline is dropped and does not pass through the test piece within 30 seconds and a bowl-shaped water droplet remains, the test is finished, and the number of drops until the test is finished is taken as a test value.
The measurement is performed 5 times by the above method, and the average value is adopted as the number of water permeation.

Wet back test First, a sheet to be measured is cut into 100 × 100 mm to form a test piece. Next, the mass W1 of 10 measurement filter papers (qualitative filter papers with a diameter of 55 mmφ (# 2 (No. 2): equivalent to JIS P 3801 type 2)) is measured with an electronic balance.
Next, a sufficient amount of physiological saline can be obtained by stacking 5 sheets of impregnating filter paper (absorbing paper for hand-making test of TAPPI T205 stipulated paper, for example, water-absorbing filter paper No.26-WA 180mmφ manufactured by Toyo Roshi Kaisha, Ltd.). Soak in water for at least 1 minute, allow water to reach saturation, then hang it vertically and drain for 1 minute.
Next, the drained impregnated filter paper is placed in a horizontal state and allowed to stand for 1 minute. Then, one test piece is placed on the impregnating filter paper, and ten measurement filter papers are placed on the test piece, and two wetback weights are placed thereon. The weight of one weight is 687g and the bottom pressure is 35g / cm2. After standing for 30 seconds in this state, the weight and the filter paper for measurement are removed, the test piece is taken out, and the mass W2 of the filter paper for measurement (for 10 sheets) is measured with an electronic balance.
The wet back test value is calculated as W2−W1. The measurement is performed 5 times by the above method, and the average value is adopted as the wet back amount.
The hydrophilicity is calculated by the following formula.
Hydrophilicity = number of water permeation times x amount of wet back

The basis weight of the upper sheet 202A and the lower sheet 202B is preferably 15 g / m ² or more. If the basis weight of the upper sheet 202A and the lower sheet 202B is less than 15 g / m ² , the liquid return amount increases, which may cause discomfort to the wearer and may cause a rash. For the upper sheet 202A and the lower sheet 202B, 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.

  Then, after sandwiching the absorbent layer 210 between the upper sheet 202A and the lower sheet 202B, the upper sheet 202A and the lower sheet 202 are fixed using a hot-melt adhesive over the entire circumference, whereby the absorbent article 200 is fixed. Can be manufactured. 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. .

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.
For example, when embossing is performed on the absorption layer, the embossing pattern may be a plurality of continuous linear shapes or a combination thereof, and specifically, may be an arbitrary shape such as a straight line, a curved line, a lattice shape, or a mesh shape.

<Manufacture of absorbent articles>
As Examples 1-2, the absorbent article 200 shown in FIGS. 1-2 was manufactured. The upper sheet 202A and the lower sheet 202B were air-through nonwoven fabrics having a basis weight shown in Table 1, and the hydrophilicity was adjusted by changing the type of the hydrophilized oil agent (surfactant). Of the types of hydrophilically treated oil agents in Table 1, “for weakly durable hydrophilic” is an alkyl phosphate ester salt, and when wetted with water, the hydrophilically treated oil agent flows out more than “for durable hydrophilic” described later. It is a type that is easy and has a slightly lower hydrophilicity. "For durable hydrophilic" is a mixture of alkylfort salt having 10 to 30 carbon atoms and a betaine compound having 10 to 30 carbon atoms, which is more hydrophilic than "for weakly durable hydrophilic" even when wet. The treated oil remains on the fiber surface for a long time and is highly hydrophilic. Sheets having a hydrophilicity of 10.0 or more were classified as “highly hydrophilic” types, and sheets having a hydrophilicity of less than 10.0 were classified as “lowly hydrophilic” types in Table 1.
The maximum length of the absorbent article 200 in the longitudinal direction was 490 mm, and the length in the short direction was 190 mm. Other characteristics such as dimensions are shown in Table 1.

The absorbent article of Comparative Example 1 was the same as Examples 1 and 2 except that the same sheet (“low hydrophilicity” type) was used as the upper sheet and the lower sheet.
The following evaluation was performed about the obtained absorbent article and each component.

Basis weight: measured based on JIS P8124.
The basis weight was measured after maintaining the equilibrium state under the temperature and humidity conditions specified in JIS-P8111 (23 ± 1 ° C., 50 ± 2% RH).
The measurement of the hydrophilicity of the upper sheet and the lower sheet was as described above.

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 shorter the absorption rate, the better the absorption performance.

Liquid return amount: Saline (150 ml and 200 ml, respectively) was injected into the center of the absorbent article, and after 10 minutes, filter paper (No. 2 filter paper manufactured by ADVANTEC, diameter: 55 mm) was measured in advance. Placed in the center, 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 smaller the liquid return amount, the better the absorption performance.
Repeated absorption: 20ml of physiological saline was dripped and poured into the same location on the center of the upper sheet every 3 minutes without load, and it was visually determined that the upper sheet did not absorb and was water repellent (liquid flow) The number of drops until was measured.
Amount transferred to combined diaper: The absorbent article was allowed to stand on a combined diaper having a sufficient absorption amount (a paper diaper having an area larger than that of the absorbent article and a total absorption amount of 2 times or more). A fixed amount of physiological saline was dropped into the center of the absorbent article, and the weight of water absorbed by the combined diaper was measured after 30 minutes.
The obtained results are shown in Table 1. In Table 1, “upper surface side” indicates a case where physiological saline is dropped on the surface of the upper sheet, and “lower surface side” indicates a case where physiological saline is dropped on the surface of the lower sheet. Therefore, the value of the amount transferred to the combined diaper on the “upper surface side” is the value when the absorbent article is placed on the combined diaper so that the lower sheet faces the combined diaper, and physiological saline is dropped on the upper sheet. Indicates.

  As is clear from Table 1, in each Example in which the hydrophilicity of the upper sheet is higher than the hydrophilicity of the lower sheet, the hydrophilicity of the upper sheet and the lower sheet is higher than that of Comparative Example 1 having the same hydrophilicity. The absorption rate on the upper sheet side (upper surface side), the number of repetitions of absorption, and the amount transferred to the combined diaper increased, and the liquid return amount decreased. In particular, in the case of Example 2 where the difference in hydrophilicity between the upper sheet and the lower sheet is larger than that in Example 1, the absorption rate on the upper sheet side (upper surface side) and the shift amount to the combined diaper are further increased. The amount of liquid return was further reduced.

200 Absorbent article 202A Upper sheet 202B Lower sheet 210 Absorbing layer

Claims (1)

An absorbent article having an absorbent layer, a liquid-permeable upper sheet covering the upper surface of the absorbent layer, and a liquid-permeable lower sheet covering the lower surface of the absorbent layer,
The hydrophilicity of the upper sheet is higher than the hydrophilicity of the lower sheet,
The upper sheet and the lower sheet are both made of a nonwoven fabric imparted with hydrophilicity,
The hydrophilicity of the upper sheet is 10.0 or more, and the hydrophilicity of the lower sheet is 1.0 or more and less than 10.0 ,
An absorbent article in which a difference in hydrophilicity between the upper sheet and the lower sheet is 3.0 or more .

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