JPH0871103A - Disposable diapers - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a disposable diaper that is easy to wear, has sufficient stretchability during wearing, and is excellent in fit and displacement prevention to the wearer's waist area. [Structure] A liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and an absorber 4 interposed between these two sheets 2 and 3 are provided at the peripheral edge of a waist opening 6. West gather 16 and the waist gather 16
A disposable diaper 1 having a waistline gather 17 provided in parallel with the waistline gather: an elastic stretchable member 21 forming the waistline gather 17 crosses at least a part of a region where the absorber 4 exists; The stretchability of the region where the absorbent body 4 and the elastic stretchable member 21 are present is an extension rate of less than 25% before wearing the diaper, and
When the diaper is worn, the stretch rate is 25% or more; and the absorbent body 4 has an elastic modulus of 1.0 × 10 ^{3 to} 2.5.
× 10 ⁵ g / cm ² and flexural rigidity 20 to 2
It is 00 g / cm;

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disposable diaper, and more particularly to a deployable disposable diaper which is easy to wear and has sufficient elasticity during wearing.

[0002]

2. Description of the Related Art A general deployable disposable diaper is provided with a liquid permeable top sheet, a liquid impermeable back sheet and an absorbent body interposed between these sheets. The waist opening and the pair of leg openings are formed by joining the abdominal waistline portion located on the abdomen side of the wearer and the back side waistline portion located on the back side by the joining means when worn. A waist gather is provided at the peripheral edge of the waist opening, and a waistline gather is provided near the waist gather separately from the waist gather.

However, in such a conventional disposable diaper, when the diaper is unfolded, the waist gathers shrink too much and the absorbent body is crushed or crushed, resulting in a shape in which the unfolded diaper is shrunk as a whole. Therefore, there is a problem that a problem occurs when the wearer wears the diaper.

For example, Japanese Laid-Open Patent Publication No. 61-275402 proposes a disposable diaper in which a waist barrier having elasticity is arranged on the abdominal side and the back waistline of the diaper. Since the waist barrier is an integrated body that also has the function of waist gathers, there is a problem in that it is very difficult to wear the diaper (poor wearability) because parts unnecessary for improving fitability contract.

Therefore, it is an object of the present invention to be easy to wear,
Another object of the present invention is to provide a disposable diaper that has sufficient stretchability during wearing and is excellent in fit and displacement prevention against the wearer's waist area.

[0006]

Means for Solving the Problems As a result of intensive studies, the inventors of the present invention have found that when the diaper is deployed, the crushing crush in the region where the absorbent body and the waistline gathers are present is the elastic modulus of the absorber and the waistline gathers. It was found that it has a very close relationship with the elastic properties of the elastic member.

The present invention has been made on the basis of the above findings, and comprises a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body interposed between these sheets. A deployment type disposable diaper having waist gathers provided around the periphery of the waist portion and waist gathers provided in parallel with the waist gathers, wherein the elastic stretchable member forming the waist gathers.
It crosses at least a part of the region where the absorber is present; the stretchability of the region where the absorber and the elastic stretchable member are present is less than 25% of elongation before wearing the diaper, and Stretch rate of 25 while wearing a diaper
% Or more; and the absorber has an elastic modulus of 1.0 ×
The above object is achieved by providing a disposable diaper characterized by having a bending rigidity of 10 ^{3 to} 2.5 × 10 ⁵ g / cm ² and a bending rigidity of 20 to 200 g / cm ^2. .

[0008]

In the disposable diaper of the present invention, since the elastic stretchable member forming the waistline gather crosses at least a part of the region where the absorber exists, excessive shrinkage of the elastic stretchable member is caused by the absorber. To be prevented. Therefore, when the diaper is unfolded, the diaper is less likely to shrink, which makes it easier for the wearer to wear the diaper. Further, since the elastic modulus of the absorbent body before wearing is large, the absorbent body before wearing maintains the original shape against the contracting force of the elastic stretchable member, and the diaper is more easily applied. On the other hand, since the elastic modulus during wearing is smaller than that before wearing, it is deformed according to the wearer's body shape, and the fit to the wearer's body is also improved.

[0009]

Embodiments of the disposable diaper of the present invention will be described below in detail with reference to the accompanying drawings. Needless to say, the present invention is not limited to such embodiments. 1 is a perspective view showing a first embodiment of the disposable diaper of the present invention, and FIG. 2 is a partially cutaway enlarged development view showing a waist portion on the back side of the disposable diaper shown in FIG.

As shown in FIGS. 1 and 2, the disposable diaper 1 of this embodiment has a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and an absorbent body interposed between these sheets 2 and 3. 4, the abdominal waistline portion 5 located on the wearer's abdominal side when worn, and the back side waistline portion 5'located on the back side.
Are joined to form a waist opening 6 and a pair of leg openings 7. A waist gather 16 is provided at the peripheral edge of the waist opening 6, and a waist gather 17 that is separate from the waist gather 16 is provided in parallel with the waist gather 16. The elastic stretchable member 21 forming the waistline gathers 17 crosses at least a part of the region where the absorber 4 is present.

More specifically, as shown in FIGS. 1 and 2,
In the disposable diaper 1 of this embodiment, the absorber 4 is formed in a rectangular shape. Top sheet 2 and back sheet 3
Is curved and formed in an hourglass shape in which the crotch portion is twisted.
Then, as shown in FIG. 2, elastic members 8 are stretched between the top sheet 2 and the back sheet 3 in the leg portions 7'and the front and rear waist portions 9 and 9 ', respectively. As shown in FIG. 1, the elastic member 8 contracts in a free state, and the waist opening 6 and the leg opening 7 of the diaper are shown.
Waist gathers 16 and leg gathers are formed on the periphery of the diaper so that the diaper can be fitted to the waist and crotch region of the wearer. Also, on the left and right flap portions 15, 15 of the back waistline portion 5 ',
A tape fastener 10 is provided as a joining means for joining the abdominal waistline portion 5 and the back side waistline portion 5 '.

As the surface sheet 2, a liquid permeable sheet that allows excrement to permeate into the absorbent body is used, and one having a feeling close to that of underwear is particularly preferable. As such a liquid-permeable sheet, for example, a woven fabric, a non-woven fabric or a porous film of a thermoplastic resin is preferably mentioned. Liquid leakage may occur from the peripheral portion of the surface sheet 2 due to bleeding of urine or the like, but such a problem is caused by applying a silicone compound or a hydrophobic compound such as paraffin wax to the peripheral portion of the surface sheet 2, Alternatively, after applying a hydrophilic compound such as alkyl phosphate to the entire surface sheet 2 in advance,
This can be prevented by washing the peripheral portion of the topsheet 2 with warm water to make this portion water repellent.

The back sheet 3 is a film sheet obtained by adding a filler of an inorganic compound or an organic compound to a thermoplastic resin, performing melt extrusion from a T die or a circular die, and then uniaxially or biaxially stretching it. Wet liquid impermeable sheets are preferred. In particular, it is preferable to have a feeling close to that of underwear. As such a liquid impermeable sheet, for example, a composite material of a thermoplastic resin film and a non-woven fabric is preferably cited. In the present embodiment, the back sheet 3 is formed of a material, such as a moisture permeable polypropylene, to which the above-mentioned tape fastener 10 can be attached on the entire surface thereof so that the tape fastener 10 can be peeled off.

As the absorber 4, fluff pulp obtained by crushing wood pulp can be used, and it is preferable to use a fluff pulp in combination with this. Particularly preferred is a mixture of a thermoplastic resin, fluff pulp and a super absorbent polymer which has been heat treated. The superabsorbent polymer may be used as a mixture with the fluff pulp, or may be present only in a specific part of the absorbent body 4, that is, in any part of the upper part, the middle part and the lower part. As the super absorbent polymer, a particulate polymer having a retention performance capable of absorbing and retaining a liquid 20 times or more its own weight and having a gelling property is preferable. As such a super absorbent polymer,
For example, there are starch-based, cellulosic-based and synthetic polymers, particularly saponified starch-acrylic acid (salt) graft copolymers, starch-acrylonitrile copolymers,
Preferable examples include crosslinked products of sodium carboxymethyl cellulose and acrylic acid (salt) polymers.

As the elastic member 8, generally, polyurethane, natural rubber or the like in the form of a thread or a band can be used, and particularly, a thread rubber, a flat rubber, a film type rubber or a film-like foamed polyurethane can be preferably mentioned. . The elastic member 8 has a stress of 40 to 100 when stretched by 50%.
It is preferably in grams.

The material forming the tape fastener 10 is not particularly limited, and a tape material, an adhesive material or the like which is commonly used in the relevant technical field can be used.

The characteristic parts of the disposable diaper 1 of the present embodiment will be described. In the disposable diaper 1 of the present embodiment, the elasticity of the region where the absorber 4 and the elastic expansion / contraction member 21 are present is diaper. Before wearing, the stretch ratio is less than 25%, preferably 10 to 20%, and before wearing, the stretch ratio is 25% or more, preferably 25 to 80%. That is, the diaper is characterized in that it has substantially no elasticity before being worn, and that it exhibits elasticity while being worn. The expansion rate can be obtained from the following formula. Stretch rate = Absorber product width / 50g Weighted absorbent body width x 100
-100

The absorbent body 4 has an elastic modulus of 1.0 × 10 ^{3 to} 2.5 × 10 ⁵ g / c before wearing the diaper.
m ² , preferably 7.0 × 10 ^{3 to} 1.8 × 10
^{It is 4} g / cm ² and is 50% or less of the elastic modulus before wearing while wearing. By making the absorbent body 4 in this way, the absorbent body 4 retains its original shape against the contracting force of the waistline gathers 17 or the waist gathers 16 and the diaper does not shrink before the diaper is worn. It becomes easy to wear a diaper. On the other hand, absorber 4 while wearing
Since it also has elasticity, it deforms according to the wearer's body shape and fits the wearer's body. If the elastic modulus of the absorbent body 4 before wearing is less than this, shrinkage occurs in any case and it becomes difficult to wear, and if it exceeds this, shrinkage does not occur even after wearing in any case. Incidentally, in the present invention, before wearing the diaper means that the diaper is in a non-deformed state before being worn by the wearer, and during wearing, the diaper is in a deformed state when the diaper is worn by the wearer. It means that.

The absorber 4 has a flexural rigidity of 20 to 200 g / cm before wearing, and preferably 50 to 10 g.
It is 0 g / cm. This is because if the bending rigidity is less than this, the strain is lost, and the absorber is fluffy, and if it exceeds this, the strain is too strong and it becomes difficult to deform. The flexural rigidity is a parameter related to the strength of the absorber 4, and a large value of the flexural rigidity increases the stiffness, and a small value of the flexural rigidity decreases the stiffness and weakens.

In the present invention, the elastic modulus and flexural rigidity of the absorber 4 are obtained from the following equations by the method shown in FIG. That is, the absorber 4 is passed between the two fulcrums, a weight is placed on the approximate center of the absorber 4 to apply a weight, and the amount of bending due to the absorber 4 bending by the weight of the weight is measured. The elastic modulus and the bending rigidity of the absorber 4 are calculated from this bending amount and the following equation. Modulus of elasticity = [distance between fulcrums ³ / (4 x width x thickness ³ )] x weight / deflection amount Bending rigidity = weight / deflection amount

In the present invention, in order to produce the absorber 4, a fluff pulp obtained by crushing wood pulp is mixed with a superabsorbent polymer and, if necessary, other additives and shaped into the shape of the absorber. Is wrapped with tissue paper and passed through a pair of embossing rolls, whereby an absorbent body having rigidity is obtained. Since the rigidity of the absorber 4 depends on the pressure applied to the embossing roll, the pressure of the embossing roll is adjusted so that the elastic modulus of the absorber 4 is within the above range. If necessary, an adhesive such as hot melt may be applied in a spiral shape to increase the rigidity.

As shown in FIGS. 1 and 2, a waist gather 17 is provided in parallel with the waist gather 16 provided at the peripheral edge of the waist opening. The elastic stretchable member 21 forming the waistline gather 17 crosses at least a part of the region where the absorber 4 is present. The elastic property of the elastic elastic member 21 is closely related to the elastic modulus of the absorber 4, but the stress at 100% elongation of the elastic elastic member 21 is preferably 50 to 500 gf, and particularly 100 to 100 gf. It is preferably 300 gf. If the stress at 100% elongation is less than this, there is no change before and after wearing, it does not function sufficiently, the diaper slips off, and if it exceeds this, the stretching force is too strong and it touches the skin. This is because it will cause damage. In FIG. 2, the elastic expansion / contraction member 21 partially crosses the absorbent body 4 in the longitudinal direction of the diaper, but the present invention is not limited to this embodiment, and as another embodiment, for example, elastic expansion / contraction. The entire member 21 may traverse the absorbent body (see FIG. 5 below).

The length of the elastic expansion / contraction member 21 in the girth direction of the diaper is not particularly limited, but it is longer than the width of the absorbent body 4 and the flap portion of the diaper is arranged so that the end of the elastic expansion / contraction member 21 exceeds the absorbent body 4. It is preferable that it reaches 15. In this case, it is preferable that the stretchable physical property in the region where the absorber 4 is present in the waist gathers 17 is different from the stretchable physical property in the region where the absorber is not present. That is, in FIG. 2, the stretchable physical properties of the portion of the waistline gather 17 on the absorber 4 and on the extension of the absorber 4 in the longitudinal direction (the region indicated by b in FIG. 2) are
It is preferable that the stretchable physical properties of the portion existing on the flap portion 15 (the area indicated by a in FIG. 2) are different. The stretchable physical properties referred to here mean the physical properties of the product. By doing so, the effect of improving the fit property for preventing the slip-off is produced. As described above, there is no particular limitation on the method for making the stretchable physical properties different between the region a and the region b in FIG. 2, and for example, when the elastic stretchable member 21 is stretched around the waist gathers 17, Elastic elastic member 2
1 may be applied differently in the area a and the area b, and the elastic property of the elastic expansion / contraction member 21 itself may be a.
Different areas can be used for the area b and the area b.

Elastic elastic member 2 in the longitudinal direction of the diaper
The length of 1 is not particularly limited, but is preferably 5 to 30 mm, and particularly preferably 10 to 25 mm. The material and shape of the elastic stretchable member 21 are not particularly limited, and the same members as those used for the waist gathers 16 and leg gathers described above, such as thread rubber, flat rubber, film type rubber, or film-like foam. Polyurethane or the like can be used. For example, in the case of using rubber thread, as shown in FIG.
a, 21b, and 21c are arranged, and among the elastic elastic members 21, the second elastic elastic member 21b and the third elastic elastic member 21c are arranged on the absorber 4.

In the present invention, the positional relationship between the elastic expansion / contraction member 21 and the tape fastener 10 is not particularly limited, but it is preferable that at least a part of the elastic expansion / contraction member 21 is extended in the girth direction of the tape fastener 10. To be present in. By arranging in this way, the elastic expansion / contraction member and the tape fastener are interlocked with each other, and slippage of the diaper is further prevented.

The product expansion and contraction rate of the waistline gathers 17 before wearing the diaper is preferably 10 to 70%, and particularly preferably 15 to 45%. This is because if the product expansion / contraction ratio is less than this range, the effect of preventing slipping off is weak and the waist gathers do not sufficiently act, while if it exceeds this range, the expansion / contraction force is too strong and the skin is affected. In the present invention, the product expansion / contraction rate (%) is defined by the following formula: Product expansion / contraction rate (%) = product width of diaper / diaper width at 50 g load × 100-100, where 50 g load The width of the diaper is 50 g in the girth direction of the diaper at the waist gather 17 portion.
The width of the diaper when the load is applied.

As described above, the stretchability of the waist gather 17 is closely related to the elastic modulus of the absorbent body 4, but the waist gather 17 has the tape fastener 10 in the natural length of the diaper, The shrinkage force when stretched 30 mm in the girth direction of the diaper is preferably 50 to 500 gf, and particularly preferably 100 to 300 gf. This is because if the shrinking force is less than this, the effect of preventing slipping-off is not seen, and if the shrinking force exceeds this, too much force is applied to hold the tape, and it becomes difficult to apply the diaper.

In the present invention, the waist gathers 17
May be provided on either the abdominal waistline portion 5 or the back waistline portion 5 ', or may be provided on both the abdominal waistline portion 5 and the back waistline portion 5'as required.

The disposable diaper of the present invention is shown in FIGS.
The structure shown in FIG. 7 can also be used. Here, FIGS. 4 to 7 are partially cutaway enlarged views showing the waist portion of the diaper in the second to fifth embodiments of the disposable diaper of the present invention (FIG. 2).
(Corresponding figure). Further, the explanation given in the above-mentioned first embodiment is appropriately applied to the points other than the points described below.

The disposable diaper of the second embodiment shown in FIG. 4 has a waist barrier 20 extending from the edge of the waist opening 6 toward the absorbent body 4 between the absorbent body 4 and the topsheet 2. The waist barrier 20 is stretched with an elastic stretchable member 21 to form a waistline gather 17. There is no particular limitation on the method of stretching the elastic stretchable member 21, and for example, the waist barrier 20 on the absorber 4 is folded back to the surface sheet 2 side to form a double structure, and the elastic stretchable member 21 is sandwiched between them. Place in the girth direction of the diaper. In this case, it goes without saying that the elastic stretchable member 21 forming the waistline gather 17 crosses at least a part of the region where the absorber 4 exists.

As described above, by providing the waistline gathers 17 on the waist barrier 20, liquid leakage from the joint between the topsheet 2 and the backsheet 3 in the waistline of the wearer is prevented when the wearer is lying down. At the same time, there is an effect that a fit feeling and a shift preventing property of the wearer's waist portion are improved.

The material for forming the waist barrier 20 may be a polyolefin compound to which an inorganic compound is added. The thickness is preferably 20 to 150 μm, more preferably 30 to 50 μm. This is because if the thickness is less than this, the strength of the waist barrier 20 is weak and the workability during diaper production is poor, and if it exceeds this, the diaper becomes stiff and the usability deteriorates.

In the disposable diaper of the third embodiment shown in FIG. 5, both of the two elastic stretchable members 21 are provided on the absorbent body 4, and the elastic stretchable member 21 is attached to the absorbent body 4.
Only the portion (hatched portion in FIG. 5) excluding the portion existing above is adhesively fixed and arranged.

In the disposable diaper of the fourth embodiment shown in FIG. 6, the three elastic expansion / contraction members 21 are provided only on the left and right corners of the absorbent body 4 (and in the vicinity thereof) (hatched portions in FIG. 6). It is arranged with adhesive bonding.

In the disposable diaper of the fifth embodiment shown in FIG. 7, three elastic stretchable members 21 are arranged by being adhered and fixed only in the absorbent body 4 and a region in the vicinity thereof (hatched portion in FIG. 7). There is.

The present invention is not limited to the above-described embodiment, and for example, the waist circumference gather 17
Can be provided in the abdominal waistline portion 5 with the same structure, and the number and type of the elastic expansion / contraction members 21 can be appropriately changed.

[0037]

EFFECTS OF THE INVENTION The disposable diaper of the present invention is excellent in fit and displacement prevention to the waist of the wearer, and is easy to put on. It has excellent leakage prevention at the joint.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a disposable diaper of the present invention.

FIG. 2 is a partially cutaway enlarged development view showing a waist portion on the back side of the disposable diaper shown in FIG.

FIG. 3 is a diagram illustrating a method of measuring elastic modulus and bending rigidity of an absorber.

FIG. 4 is a partially cutaway enlarged development view (corresponding to FIG. 2) showing a back waist portion in a second embodiment of the disposable diaper of the present invention.

FIG. 5 is a partially cutaway enlarged development view (corresponding to FIG. 2) showing the waist portion on the back side in the third embodiment of the disposable diaper of the present invention.

FIG. 6 is a partially cutaway enlarged development view (corresponding to FIG. 2) showing the waist portion on the back side in the fourth embodiment of the disposable diaper of the present invention.

FIG. 7 is a partially cutaway enlarged development view (corresponding to FIG. 2) showing the waist portion on the back side in the fifth embodiment of the disposable diaper of the present invention.

[Explanation of symbols]

 1 Disposable diapers 2 Topsheet 3 Backsheet 4 Absorber 5 Abdominal waistline 5'Back waistline 6 Waist opening 7 Leg opening 7'Leg 8 Elastic member 10 Tape fastener 15 Flap 16 Waist gather 17 Waist gather 20 waist barrier 21 elastic member

Claims (3)

[Claims] 1. A liquid-permeable topsheet (2), a liquid-impermeable backsheet (3), and both sheets (2),
(3) A waist gather (16) having an absorber (4) interposed between the waist gather (16) and a waist circumference provided in parallel with the waist gather (16). A deployable disposable diaper (1) having a gather (17), wherein an elastic stretchable member (21) forming the waistline gather (17) covers at least a part of a region where the absorber (4) exists. Crossing; the stretchability of the region where the absorbent body (4) and the elastic stretchable member (21) are present is less than 25% of the stretch rate before wearing the diaper, and while wearing the diaper. The stretch rate is 25% or more; and the absorbent body (4) has an elastic modulus of 1.0 × 10 ³ to 2.
5 × 10 ⁵ g / cm ² and flexural rigidity of 20 to
200 g / cm; a disposable diaper characterized by: 2. Of the waist circumference gathers (17),
The stretchable physical properties in the region where the absorber (4) is present are
The disposable diaper according to claim 1, wherein the disposable diaper has a different elastic property in a region where the absorber does not exist. 3. The disposable diaper according to claim 1 or 2, wherein the product stretch ratio of the waist gathers (17) before wearing the diaper is 10 to 70%.