JPH0284960A - Absorptive article - Google Patents

Abstract

PURPOSE:To maintain a desirable shape as against various movements during wearing an to obtain an excellent leakproof property by disposing an adhesive tape consisting of a 1st tacky adhesive layer, elastic sheet and 2nd tacky adhesive layer on the surface to come into contact with clothing and using the elastic sheet having a specific modulus in compression. CONSTITUTION:The absorptive article consisting of a liquid permeable surface material 1, an absorber 2 and a liquid impermeable leakproof material 3 is disposed with an elastic tacky adhesive tape 7 consisting of the 1st tacky adhesive layer 4, the elastic sheet 5 having the specific modulus in compression and the 2nd tacky adhesive layer 6 on the liquid impermeable leakproof material side, i.e., a non-use surface material side. The elastic sheet 5 having a recovering property is exemplified by formed materials, for example, foamed polyethylene and foamed polyurethane in addition to sheet-like materials and laminates of rubber such as styrene/butadiene copolymer and polybutadiene and elastomers such as polyurethane and polyolefin. The above-mentioned elastic sheet is required to have 300 to 3000g/cm<2> modulus in compression. The modulus in compression is regulated by the requirements specified in JIS K 7220.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to absorbent articles such as sanitary napkins, disposable diapers, and incontinent pads, and more particularly to absorbent articles typified by sanitary napkins. The present invention relates to an absorbent article that has dramatically improved absorption properties, especially leak-proofing properties during activities.

[Conventional technology and its problems]

BACKGROUND ART Research has been actively conducted to improve the absorption characteristics of absorbent articles, and numerous results have been reported. The main improvements are to improve the liquid absorption speed, suppress the return of liquid from the absorbent body to the surface after absorption, reduce stickiness on the surface, and as a result, give the user a smooth feel. The purpose is to provide a comfortable situation.

To give a specific example, research on surface materials revealed that rayon staples, which have been commonly used in the past, have a sticky surface because they are hydrophilic. Proposals have been made to reduce the stickiness of the surface by changing this to a hydrophobic material, for example, a synthetic fiber aggregate such as polypropylene staple or polyester staple.

In addition, as a material for absorbent bodies, polymer absorbent materials (
It has been proposed to improve absorption capacity and at the same time prevent the liquid from returning to the surface material after absorption by applying superabsorbent polymers. As a result, it can be said that the problem of leakage due to so-called insufficient absorption capacity has been largely solved.

However, even if materials such as superabsorbent polymers are made to function effectively, when absorbent articles are actually used, they are used in the crotch of the human body, so they are subject to significant deformation due to the pressure applied when worn. As a result, the problem is that it induces leakage and the effectiveness is drastically reduced.

This point will be explained in more detail using sanitary napkins as a representative example. When a sanitary napkin is worn, it is compressed between the crotches, so that the central region of the napkin becomes narrow. Furthermore, the central region, which absorbs menstrual blood, receives the most concentrated deformation stress, and the deformation stress applied to the napkin fluctuates due to human body movements such as closing the legs or walking, causing twisting in the central region. It will happen. In particular, this phenomenon is more likely to occur in a wet state after absorbing blood than in a dry state, and as a result, it is thought that the absorbent capacity is significantly less than the original absorbing capacity and leaks.

Therefore, various proposals have been made as means to solve these problems.

Publication of Utility Model Publication No. 60-24339 states, ``In the central region, a material made of absorbent paper or a combination of this and pulverized pulp is arranged, and in both side regions, pulverized pulp or a material mainly composed of this is arranged. However, this napkin does not solve the above-mentioned wrinkle after absorption at all, and cannot be expected to be sufficiently effective.

Furthermore, many napkins have been proposed with concave notches on the side of the absorbent body, with the idea of improving the fit by matching the shape of the crotch and the absorbent body as much as possible when worn (Japanese Utility Model Publication No. 60-25237 No., Utility Model Publication No. 60-31718 and other publications - If a filter is simply cut out in a concave shape in a part of the absorbent body, it will only reduce the absorption capacity in the area where the absorption capacity is needed, and will instead cause horizontal leakage. It causes.

On the other hand, a technology to prevent twisting by configuring a shape-retaining piece with a certain bending moment inside the absorber (Jikko Sho 6)
0-34273) has been proposed. This technology effectively prevents twisting, but in practical situations such as wearing shorts, the free deformability of the absorbent body is inhibited, and the effect is only achieved when worn in the optimal position. do not. Therefore, under the actual usage environment,
This is not necessarily an effective method for preventing leakage.

In addition, technology to prevent slippage and twisting by placing an elastic body between an absorbent article and an adhesive (Utility Model Publication No. 59-33
No. 368) has also been proposed.

Although this technology effectively prevents slippage and twisting, since the elastic body exists over almost the entire area in the lateral force direction, the rigidity of the absorbent article increases, which inevitably causes discomfort to the user. Furthermore, since an elastic body is used that has a poor effect of buffering the compressive stress applied to the absorbent article during use, there is a natural limit to the improvement in leak-proofing properties.

In conventional absorbent articles used in the crotch area, no technology has yet been developed to effectively solve the various problems described above.

[Means for solving problems]

In view of the above-mentioned problems, the inventors of the present invention have made extensive studies and have arrived at the present invention. Provided is an absorbent article that efficiently absorbs liquid excreted from the body, maintains its desired shape even during various movements during wear, and has excellent leak-proof properties.

That is, the present invention provides an absorbent article having a first surface in contact with the skin and a second surface located on the opposite side and in contact with clothing, wherein the second surface has a first adhesive layer, An adhesive tape consisting of an elastic sheet and a second adhesive layer is disposed, and the elastic sheet has a compressive elastic modulus of 300 to 3000 g/cm3 as measured in accordance with JIS K 7220. It is something.

The resilient sheet used in the present invention includes:
The requirement is that the compressive elastic modulus is 3oo to 3ooog/cII13te. This compressive elastic modulus is JIS
It is determined by the following equation (1) using the first straight line portion of the compressive stress-strain curve defined by K 7220.

Here, Ec: Compressive modulus of elasticity (g/cm3) Δσ: Difference in stress between two points on a straight line (g/cm2) Δε: Difference in strain between the same two points Compressive modulus is within the above range If so, it can be suitably used in the present invention. More preferably 1000-2
000 g/cm'. If the napkin is less than 300 g/cm', the effects of the present invention cannot be achieved, such as the napkin being easily twisted, and if the napkin is more than 3000 g/cm', the effect may be observed, but the napkin may not deform properly in response to body movements. is suppressed, giving the user a sense of discomfort, and furthermore, considering the case of actual use, the optimum range for exhibiting the effect becomes narrower, which is not the intention of the present invention.

Elastic sheets with resilience that are preferably used in the present invention include styrene-butadiene copolymers; sheet-like materials and laminates of rubbers such as polybutadiene, elastomer resins such as polyurethane and polyolefin, and foamed materials. Examples include foamed polyethylene, foamed polyurethane, foamed polybutadiene, and foamed polyvinyl chloride. Furthermore, sheet-like materials formed into corrugated shapes or into honeycomb structures can also be suitably used.

These elastic sheets with resilience are placed on the surface of the absorbent article that does not come into contact with the skin, but it is desirable that these sheets do not shift due to body movements, so they have a higher frictional force. It is necessary to develop the effect, and from this point of view, a sheet-like material or a foamed sheet with a larger contact area is most preferable.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a cross-sectional view showing a schematic structure of an example of an absorbent article of the present invention. In Figure 1, liquid-permeable surface material 1
, an absorbent article consisting of an absorbent body 2 and a liquid-impermeable leakage preventive material 3, in which a first
An elastic adhesive tape 7 consisting of an adhesive layer 4, an elastic sheet 5 having the above-mentioned specific compressive elastic modulus, and a second adhesive layer 6 is arranged. In FIG. 1, the elastic adhesive tapes 7 are arranged at each end of a substantially longitudinally elongated absorbent article, and although this arrangement is a preferable arrangement, the present invention is limited to this arrangement. isn't it.

In FIG. 1, the elastic sheets are installed at each of the horizontally opposite ends of a substantially longitudinally elongated absorbent article, and although the preferred position depends on the size of the absorbent article, it is generally In view of the size of the absorbent article that is used in practical use by being attached to the crotch, the adhesive tape 7 is designed to be absorbent, as shown in FIG. arranged symmetrically in the lateral direction of the absorbent article, and the distance 1 from the side edge of the absorbent article is 10 to 30 mm, preferably 15 to 20 m.
Preferably, it is located at m. The width of the elastic adhesive tape varies depending on the size, thickness, compression modulus, bending moment, etc. of the absorbent article, but it is desirable that the elastic tapes at both ends do not overlap significantly when worn. ~20+am, more preferably 10mm~15n+m.

In this case, it is preferable to provide a gap between the elastic adhesive tapes at both ends, and furthermore, at least one elastic adhesive tape may be arranged between the gaps. In the present invention, a continuous wide single sheet of elastic adhesive tape, that is, one in which there are no gaps between the elastic adhesive tapes, is not preferable in terms of usability and leakage prevention because the movement of the crotch is directly applied to the absorbent article. .

Further, the elastic adhesive tape does not have to be straight, and can be arbitrarily selected such as curved or zigzag.

The thickness of the elastic sheet can be arbitrarily determined depending on the value of the compressive elastic modulus, but considering the situation where it will be used in the groin area,
．． It is preferably 0 mm or less. More preferably from 1.0 mm
It is 4.01.

Regarding the length in the vertical direction, it is preferable that the length is biased toward the front end. Further, as for its preferable position, although it depends on the size of the absorbent article, the distance Lt from the front end of the absorbent article is 25 to 35 mm, preferably 30 mm.
Around mm, vertical L2 length is 50mm to 120mm
, preferably 60 mm to 80 mm.

In order to prevent these elastic adhesive tapes from adhering to absorbent articles and also from leaving undesirable tape residue on clothing after use, the adhesive force or adhesion force of the first adhesive layer 4 is equal to the adhesive force of the second adhesive layer 6. It is also preferable that the adhesive force is sufficiently larger than the adhesive force. This can be achieved by using known techniques such as applying known adhesives with different adhesive strengths or varying the area of application.

The elastic sheet 5 needs to act effectively with the absorbent body 2 of the absorbent article, and the first adhesive layer 4 needs to be adhered to the leak-proof sheet 3.

If necessary, it is also a preferable method to further use hot melt, double-sided adhesive tape, adhesive, or the like to bond the elastic sheet 7 and the leak-proof sheet 3 together.

FIG. 3 is a vertical cross-sectional view showing a schematic structure of another example of the absorbent article of the present invention, and FIG. 4 is a cross-sectional view of the absorbent article taken along line AA' in FIG. 3.

That is, a shape-retaining piece 17 made of an elastic sheet having resilience is arranged on the surface 13 of the absorbent article on the side that does not come into contact with the skin.

In FIGS. 3 and 4, 11 is a liquid-permeable surface material, 13 is a liquid-impermeable leak preventive material, and 12 is an absorbent body. On the leak preventive material 13, a first adhesive layer 14, an elastic An elastic adhesive tape 17 consisting of a sheet 15 and a second adhesive layer 16 is arranged.

The size of the elastic sheet having a specific compressive elastic modulus defined in the present invention is not particularly limited, but it can suitably adhere to the user's body and maintain a desired shape even when worn. If possible, the unused surface material shown in Figure 3 (
As shown in Fig. 5, which corresponds to the plan view of the leakage preventive material, the width 6 is preferably 20 to 50 m1, and the width is 30 mm to 50 mm.
It is. The longitudinal direction (longitudinal direction) L2 can be arbitrarily determined depending on the size generally used in practical use, but it is preferably 40 mm to 160 m+++.

In the present invention, it is intended to use an elastic sheet with a restoring force that fits suitably in the crotch area and does not fluctuate due to body movements. Therefore, the examples shown in FIGS. 3 and 4 are used. The preferable position of the elastic sheet in this case is that it is located at the center of the absorbent article in the lateral direction and is biased towards the front end. This position and size can be freely determined depending on the position where excretion is performed and the size that is practically used.

Furthermore, the elastic sheet may be continuous in the lateral direction or may be divided, but if it is divided, it is desirable that the distance between the gaps is 10III+1 or less.

If it is 10 mm or more, the effect of not changing with respect to body movements will be weakened, which is not preferable.

The thickness of the elastic sheet varies somewhat depending on the compression modulus, but I
IIIll to 7III111, more preferably 2 mm
~5IllI.

In the case of the examples shown in FIGS. 3 to 5, since the elastic sheet 15 is arranged on the surface of the side 13 of the absorbent article that does not come into contact with the skin, the Alternatively, it is preferable to divide it into several parts and adhere or apply a conventional adhesive tape or hot melt adhesive. Furthermore, in order to prevent undesirable residue on clothing after use, it is desirable that the adhesive force or adhesive force of the absorbent article to the absorbent body side is sufficiently higher than the adhesive force or adhesive force to the clothing side. This can be achieved by using means such as making the composition of the double-sided adhesive or hot melt adhesive different between the absorbent body side and the clothing side, or making the adhesive application area different.

〔Example〕

During the evaluation, commercially available sanitary napkins “Kuchie” (
By removing the anti-slip material (manufactured by Kao ■) and the surface material, and replacing it with an olefin heat-bonded nonwoven fabric as the surface material and various elastic tapes shown in Tables 1 and 2 as the anti-slip material, sanitary A hypothetical napkin sample was evaluated by the following method. Incidentally, an adhesive containing a vinyl acetate-acrylic acid ester copolymer as a main component was used for the first and second adhesive layers of the elastic tape.

Evaluation method (1) Dynamic absorption amount and twist: Measurement was carried out using a female lumbar movable human body model as shown in FIG. As shown in Figure 7, a human model was fitted with sanitary napkins and sanitary shorts, and horse defibrinated blood was injected through a tube under specified walking conditions, and leakage was observed. The infusion was stopped at a certain time and the dynamic uptake was evaluated. The test was conducted using 10 samples, and the average value was taken as the dynamic absorption amount. It can be said that the larger the dynamic absorption amount is, the higher the leak-proofing property is.

In addition, the state of twisting of the sample after dynamic absorption measurement was ranked into the following three categories.

Grade 3: Almost no twisting is observed.

Grade 2: Slight twisting is observed.

Grade 1: Significant wrinkling is observed.

(2) Have five healthy adult women wear the discomfort test sample.
Based on the results of having respondents answer whether or not they felt uncomfortable, they were ranked as follows.

Grade 3: No one felt any discomfort.

Grade 2: One or two people felt uncomfortable.

Grade 1: Three or more people felt uncomfortable.

The results are shown in Tables 1 and 2.

Table 1 shows the experimental results when the elastic sheets are arranged as shown in FIG. 2, and Table 2 shows the experimental results when the elastic sheets are arranged as shown in FIG.

Table * Trial amount of one elastic sheet It has excellent leak-proofing properties.

On the other hand, since Comparative Example 1 does not include an elastic sheet, it is extremely prone to twisting and has poor leakproof properties.

In addition, in Comparative Example 2, the compressive elastic modulus of the elastic sheet was 300 g/
cm'', the elastic sheet tends to twist easily and has poor leakproof properties.On the other hand, in Comparative Example 3, the compressive elastic modulus of the elastic sheet is 30.
00 g/cm'', giving the user a significant sense of discomfort. In addition, in Comparative Example 4, the elastic sheet is present over substantially the entire width of the absorbent article, which also gives the user a significant sense of discomfort.

Therefore, it must be said that the products shown as comparative examples are extremely inadequate as absorbent articles.

Next, as shown in Examples 11 to 22 in Table 2, the absorbent articles according to the present invention do not give the user a significant sense of discomfort and have reduced twisting, so they have high leakproof properties.

On the other hand, since Comparative Example 5 does not include an elastic sheet, it is extremely prone to twisting and has poor leak-proofing properties. Also, Comparative Example 6
Since the compressive elastic modulus of the elastic body is less than 300 g/cm'', it tends to twist easily and has poor leak-proofing properties.On the other hand, in Comparative Example 7, the compressive elastic modulus of the elastic body exceeds 3000 g/cm'', Gives the user a significant sense of discomfort.

Therefore, it must be said that the products shown as comparative examples are extremely inadequate as absorbent articles.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a schematic structure of an example of the absorbent article of the present invention, FIG. 2 is a schematic plan view of the non-use side thereof, and FIG.
The figure is a cross-sectional view of another example of the absorbent article of the present invention, FIG. 4 is a longitudinal cross-sectional view taken along line A-A' in FIG. 3, and FIG. 5 is a schematic plan view of the non-use surface side thereof. , FIG. 6 is a schematic front view of the human body model used for evaluation, and FIG. 7 is a schematic front view of the human body model during testing. 1.11... Surface material 2.12... Water absorber 3.13... Leak proof material 4.14... First adhesive 5.15... Elastic sheet 6.16... Second adhesive 7.17...Elastic adhesive tape

Claims (1)

[Claims] 1. In an absorbent article having a first surface in contact with the skin and a second surface located on the opposite side and in contact with clothing, the second surface has a first adhesive layer, an elastic sheet and a second surface.
An absorbent article characterized in that an adhesive tape consisting of an adhesive layer is disposed, and the elastic sheet has a compressive elastic modulus of 300 to 3000 g/cm^3 as measured in accordance with JIS K 7220.