JPH08164163A - Throw-away diaper - Google Patents

Abstract

PURPOSE: To provide a diaper capable of rapidly absorbing urine with the absorber of a throw-away diaper, lessening the user's uncomfortability by suppressing the reversion thereof and decreasing the cause for the occurrence of skin sores. CONSTITUTION: An absorber 3 of the throw-away diaper having the absorber 3 between a liquid permeable front surface sheet 1 and a liquid impermeable rear surface sheet 2 is constituted of a first absorber layer 8 to be arranged on the liquid permeable front surface sheet 1 side and a second absorber layer 9 to be arranged on the liquid impermeable front surface sheet 2 side. Different section fibers are compounded at 5 to 60wt.% with at least the first absorber layer 8 and highly water absorbent high-polymer materials are compounded with the inside of the second absorber layer 9.

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 disposable diaper excellent in absorption and retention of urine and the like.

[0002]

2. Description of the Related Art A disposable diaper has an absorbent body composed of cotton-like pulp, super absorbent polymer, etc. disposed between a liquid-permeable front sheet and a liquid-impermeable back sheet. The urine is absorbed by the absorber through the topsheet. At this time, the absorber is required to promptly receive urine (hereinafter, sometimes referred to as absorption rate), but a large amount of pulp is required for the absorber to satisfy this requirement. However, as a result, the absorbent becomes thicker, and the property of holding the skin on the contrary without rewetting it (hereinafter sometimes referred to as wet back)
It is inferior and the fit is impaired. Further, although the initial absorption rate is improved by increasing the amount of pulp, when it is repeatedly used, the pulp becomes settled, and the absorption rate after several times of use (hereinafter sometimes referred to as repeated absorption rate) becomes slow. This causes user discomfort and contributes to skin irritation.

Various known diapers have been proposed to solve these problems. For example, regarding the absorption rate, the density of the upper flocculent pulp is reduced as much as possible by making the upper liquid-permeable sheet hydrophilic as much as possible, making it thin, or providing pores.
It is known to adjust to 0.1 g / cm ³ or to make the surface properties of the cotton-like pulp as hydrophilic as possible. In order to reduce the wet back, the porous liquid-permeable sheet is made as hydrophobic as possible or has a certain thickness, and further, it is carried out by a device to accelerate the diffusion of the liquid in the layer of cotton-like pulp. Specifically, it has been proposed to arrange a perforated partition layer between fluff pulps (Japanese Patent Laid-Open No. 61-186505). Regarding the proposal regarding the above properties, in addition to that, a porous structure is arranged between the top sheet and the back sheet (JP-A-60-253447), and the density of the upper flocculent pulp is 0.03 to O.07 g / cm ^3. (Japanese Patent Application Laid-Open No. 56-85401) and the like, but the biggest drawback of these is that the absorption speed is particularly slow among the above-mentioned elements, and practically there is no absorption and leakage occurs. The phenomenon of is observed.

On the other hand, for example, there is a proposal that a cotton-like pulp containing polyester hollow fibers and heat-fusible fibers is used for the first absorbent layer (JP-A-57-10334). The cross section of commercially available polyester hollow fibers is circular. With this absorbent body, the absorption rate is improved to some extent because the hollow fiber does not easily retain the urine that has passed through the surface sheet, but it is difficult for urine to enter the hollow part of the hollow fiber, or because the cross section is circular, the urine is collected on the fiber. Is less likely to remain and therefore less likely for urine to diffuse along the hollow fibers. As a result, the second absorber layer cannot be effectively used, the absorbent capacity of the absorber is lowered, and the wet back is hardly improved. Further, since the heat-fusible fiber is included, the cost is increased.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a disposable diaper having an absorbent body which improves the absorption rate of the absorbent body while improving the above-mentioned drawbacks.

[0006]

The present invention relates to a disposable diaper having an absorbent body between a liquid-permeable top sheet and a liquid-impermeable back sheet, wherein the absorbent body is made of the liquid-permeable material. A first absorber layer disposed on the front sheet side and a second absorber layer disposed on the liquid impermeable back sheet side, and at least the first absorber layer has a modified cross section. A diaper for use is characterized by containing 5 to 60% by weight of fibers. Further, the present invention resides in a diaper for use characterized in that the superabsorbent polymer material is blended in the second absorbent layer. Hereinafter, the diaper used in the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 shows a cutaway plan view of a disposable diaper of the present invention, and FIG. 2 shows a cross-sectional shape of a modified cross-section fiber. The absorber used in the present invention comprises a first absorber layer disposed on the liquid-permeable surface sheet side and a liquid-impermeable layer as shown in FIG. 3 (cross-sectional view taken along line XX ′ in FIG. 1). It is preferable that the structure has a second absorbent layer disposed on the back sheet side of the conductive film, and at least the first absorbent layer contains the modified cross-section fiber. Further, each of the absorber layers or the absorber may be wrapped with a water absorbing sheet such as tissue. Reference numeral 1 denotes a liquid-permeable top sheet (hereinafter sometimes referred to as a top sheet), 2 denotes a liquid-impermeable back sheet (hereinafter sometimes referred to as a back sheet), 3 denotes an absorber, 4 Is a mat layer of the absorbent body, 5 is a high-absorbent polymer substance (hereinafter sometimes referred to as SAP), 6 is a cotton-like pulp,
Reference numeral 7 denotes a modified cross-section fiber, 8 a first absorber layer, and 9 a second absorber layer.

As shown in FIG. 1, the disposable diaper of the present invention has a front sheet 1 and a back sheet 2, and an absorber 3 between them. As the surface sheet 1, a liquid-permeable non-woven fabric, woven fabric, porous plastic film or the like made of polyester, polypropylene or the like is used. Back sheet 2
Is made of a liquid impermeable film such as polyethylene, a material obtained by laminating a liquid impermeable film with a non-woven fabric, a woven fabric, or the like. The absorber 3 is sandwiched between the front sheet 1 and the back sheet 2, and the first absorber layer 8 has a cotton-like pulp as shown in FIG. 3 (cross-sectional view taken along the line XX 'in FIG. 1). 6, the modified cross-section fiber 7 and the like, and the second absorbent layer 9 is made of SAP 5, cotton-like pulp 6 and the like.

In the present invention, the first absorbent layer 8 is composed of the cotton-like pulp 6 and the fibers 7 having atypical cross section. Examples of the modified cross-section fiber 7 include polyester, polyethylene, polypropylene, acrylic resin, nylon resin, etc., and the cross-sectional shapes thereof include T-shape, rhombus-shape, W-shape, H-shape, and amoeba-shape as shown in FIG. . The fiber diameter is preferably about 3 to 30 denier, and the fiber length is 5 mm to 50 mm, which is suitable for mixing with the cotton-like pulp 6, but is not particularly limited. By stacking these first absorber layer 8 on the second absorber layer 9, it becomes possible to reduce the wet back while improving the absorption rate.

Cotton-like pulp 6 used in the present invention
Is a sheet of chemical pulp, mechanical pulp or chemi-mechanical pulp, which is made into a cotton shape by a crusher. The pulp material is not limited to softwood, but hardwood, straw, bamboo, bagasse and kenaf are also applicable. As SAP5, a starch polymer, an acrylic acid polymer, a cellulose type, etc., which absorbs water, urine, and body fluid more than 30 times its own weight, and a polyacrylic acid type such as sodium polyacrylate is used. Most suitable in terms of absorption performance.

In the present invention, the first absorbent layer 8 is preferably blended with the modified cross-section fibers 7 in a proportion of 5 to 60% by weight of the first absorbent layer, preferably 20 to 40% by weight. More preferably.

When the proportion of the modified cross-section fibers 7 in the first absorbent layer 8 exceeds 60% by weight, the absorption rate of the absorbent 3 is increased because the water retention capacity of the modified cross-section fibers is low, but the surface sheet 1 The water absorption capacity of the above is reduced, and the wetting of the topsheet 1 increases, so that discomfort is likely to be felt, which is not suitable. If the proportion is less than 5%, no effect is observed on the absorption rate, which is not suitable.

Although SAP5 is mixed in the second absorbent layer 9 in FIG. 3, the SAP5 may be mixed uniformly or may have a distribution density in the dispersion. SAP5 is
The content is preferably 1 to 70% by weight of the second absorber layer, and more preferably 3 to 60% by weight. Moreover, the distribution of SAP5 may be distributed in layers between the first absorber layer 8 and the second absorber layer 9 as needed.

In the present invention, the density of the first absorber layer 8 is preferably 0.02 to 0.25 g / cm ³ ,
It is more preferably 0.03 to 0.2 g / cm ³ . The basis weight is preferably from 20 to 200 g / m ^2, and more preferably 50 to 150 g / m ^2. Furthermore, the density of the second absorber layer 9 is 0.03 to 0.4 g.
/ Cm3 is preferable, and 0.05 to 0.3 g /
More preferably, it is cm ³ . The basis weight is 50 to 5
It is preferably 00 g / m ² , and is 100 to 150 g.
/ M ² is more preferable.

[0015]

EXAMPLES The effects of the present invention will be described in detail below with reference to examples. Example 1 A modified cross-section fiber was added to cotton-like pulp, and the mixture was crushed, laminated, and pressed to prepare cotton-like pulp having a basis weight of 60 g / m ² , which was used as the first absorbent layer. The modified cross-section fiber used here has a T-shaped cross section with polyester as a constituent component. Fiber diameter 4
A T-shaped cross-section fiber having a denier and a fiber length of 10 mm was blended so that the ratio thereof in the first absorbent layer was 7% by weight. Further, SAP was added to the cotton-like pulp, and a lamination treatment and a pressing treatment were performed to prepare a cotton-like pulp having a basis weight of 180 g / m ² , which was used as a second absorbent layer. In practice, a polyacrylic acid salt was used for SAP, and was compounded so that the proportion of the SAP in the second absorber layer was 45% by weight. Using the first absorber layer and the second absorber layer thus separately produced, a disposable diaper having an absorber size of 400 mm × 150 mm was produced, and the absorption rate and wet back were measured.

The absorption rate here means artificial urine 50c.
It is the time until c is absorbed in the diaper, which is measured three times every 30 minutes. The wet back is the diaper after measuring the absorption rate (absorbing 50 cc three times), and a pressure of 0.05 kg / cm ² is applied for 5 minutes to put a filter paper of 100 mm × 100 mm on the surface sheet for 10 minutes. This is a measurement of the amount of artificial urine absorbed by the filter paper when the sheets were stacked and left to stand, and 15 g or less was practical. The artificial urine used here is as follows. Artificial urine composition Urea 1.9% NaCl 0.8% CaCl2 0.1% MgSO4 0.1% The balance is water

The absorption rate was also measured (50 cc was 3
After being absorbed twice), the surface sheet was lightly touched before measuring the wet back, and the dryness (hereinafter sometimes referred to as a slat feeling) was determined. The judgment criteria are as follows 3
Observing in stages, ○ or △ is practical. Feeling of Salat ○: Dry △: Moist ×: Very damp

Example 2 The proportion of the T-shaped cross-section fiber in the first absorbent layer was 20% by weight.
A diaper was prepared by using the same method as in Example 1 except that the above was used, and the measurement was performed in the same manner as in Example 1.

Example 3 The proportion of the T-shaped cross-section fiber in the first absorbent layer was 40% by weight.
A diaper was prepared by using the same method as in Example 1 except that the above was used, and the measurement was performed in the same manner as in Example 1.

Example 4 The proportion of the T-shaped cross-section fiber in the first absorbent layer was 55% by weight.
A diaper was prepared by using the same method as in Example 1 except that the above was used, and the measurement was performed in the same manner as in Example 1.

Example 5 Instead of a T-shaped cross-section fiber having a fiber diameter of 4 denier and a fiber length of 10 mm, an H-shaped cross-section fiber having a fiber diameter of 3 denier and a fiber length of 10 mm was used, and its proportion in the first absorbent layer was 40. weight%
A diaper was prepared by using the same method as in Example 1 except that the above was used, and the measurement was performed in the same manner as in Example 1.

Comparative Example 1 A diaper was prepared in the same manner as in Example 1 except that the T-shaped cross-section fiber was not mixed, and the measurement was carried out in the same manner as in Example 1.

Comparative Example 2 A diaper was prepared in the same manner as in Example 1 except that the proportion of the T-shaped cross-section fiber in the first absorbent layer was changed to 3% by weight. The measurement was performed.

Comparative Example 3 The proportion of the T-shaped cross-section fiber in the first absorbent layer was 65% by weight.
A diaper was prepared by using the same method as in Example 1 except that the above was used, and the measurement was performed in the same manner as in Example 1.

Comparative Example 4 Instead of the T-shaped cross-section fiber having a fiber diameter of 4 denier and a fiber length of 10 mm, a hollow cross-section fiber having a fiber diameter of 6 denier and a fiber length of 10 mm was used, and its ratio in the first absorbent layer was 40% by weight. %
A diaper was prepared by using the same method as in Example 1 except that the above was used, and the measurement was performed in the same manner as in Example 1.

Comparative Example 5 Blending was carried out so that the proportion of SAP in the absorber was 35% by weight, and the proportion of T-shaped cross-section fibers was 40% by weight, and lamination treatment and press treatment were carried out. Then, an absorbent body having a basis weight of 240 g / m ² was prepared, and the same examination as in Example 1 was conducted. Table 1 shows the above test results.

As is clear from Table 1, the characteristics of the examples are all good, but the comparative examples are inferior in any of them.

[0028]

[Table 1]

[0029]

EFFECT OF THE INVENTION In the disposable diaper according to the present invention, the absorbent body is composed of a mixture of cotton-like pulp and fibers of atypical cross-section, and the mat layer of the absorbent body absorbs urine a plurality of times rapidly and suppresses reversion. Since the feeling of salat is not impaired, the discomfort of the user is reduced and the cause of skin rash is reduced.

[Brief description of drawings]

FIG. 1 shows a partially cutaway plan view of a disposable diaper of the present invention.

FIG. 2 shows a cross-sectional shape of a modified cross-section fiber used in the disposable diaper of the present invention.

FIG. 3 is a disposable diaper according to the present invention, and is X- of FIG.
X'sectional drawing is shown.

[Explanation of symbols]

1. Liquid permeable surface sheet 2. Liquid impermeable back sheet 3. Absorber 4. Matt layer 5. Super absorbent polymer 6. Fluffy pulp 7. Atypical cross-section fiber 8. First absorber layer 9. Second absorber layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Daishiro Matsuda, 1-10-6 Shinonome, Koto-ku, Tokyo Shin-Oji Paper Co., Ltd. Tokyo Commodity Research Institute (72) Yoshio Hirai 1-10, Shinonome, Koto-ku, Tokyo No. 6 Shin Oji Paper Co., Ltd. Tokyo Commodity Research Institute

Claims (2)

[Claims] 1. A disposable diaper having an absorbent body between a liquid-permeable top sheet and a liquid-impermeable back sheet, wherein the absorbent body is arranged on the liquid-permeable surface sheet side. A first absorbent layer and a second absorbent layer disposed on the liquid impermeable back sheet side, and at least 5% to 60% by weight of the modified cross-section fiber is mixed in the first absorbent layer. A disposable diaper characterized by being used. 2. The disposable diaper according to claim 1, wherein a super absorbent polymer is mixed in the second absorbent layer.