JP2002017781A - Absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorbent article excellent in the leakage preventive effect for preventing leakage from the periphery of the article, having an excellent absorbent characteristic for the urine and humor. SOLUTION: The absorbent article comprises a liquid-permeable front surface sheet, a liquid non-permeable rear surface sheet, and an absorbent material disposed between the sheets. The pulp layer constituting the absorbent material comprises a first pulp layer and a second pulp layer disposed at least on the side edges of the first pulp layer. The second pulp layer is made of thermomechanical pulp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an absorbent article, and more particularly to a disposable diaper for babies, a disposable diaper for adults, a pad for incontinent persons, a urine pad for light incontinent persons, a sanitary napkin, a pad for pets, etc. The present invention relates to an absorbent article used for:

[0002]

2. Description of the Related Art Absorbent articles such as disposable diapers include a liquid-permeable top sheet and a liquid-impermeable back sheet.
It has a structure in which a plurality of absorbers composed of a hydrophilic sheet, cotton-like pulp, and an absorbent material (for example, a high-absorbency polymer) are arranged. For urine, sweat, and other body fluids, a liquid-permeable surface sheet is used. Since it passes through and is absorbed and held by the absorber, it can be used for a long time, and its usage is increasing year by year due to its convenience.

Conventionally, a disposable diaper basically comprises a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber disposed between these two sheets. The absorber has an absorbing member for receiving and retaining bodily fluids, and is required to have a function of rapidly absorbing bodily fluids, further distributing the fluid throughout the absorber, and keeping it contained in the absorber. As the absorbing member, for example, blotting paper,
Fluffed pulp, superabsorbent polymer (hereinafter referred to as SAP) and the like can be mentioned, but SAP has a large absorption capacity of body fluid but has a low absorption rate, so even if only SAP is used, it comes in contact with a large amount of body fluid at once. In this case, it is impossible to absorb the entire amount only with SAP. Therefore, a method is used in which fluff pulp is used in combination, and once fluff pulp absorbs and takes in bodily fluids, then absorbs the bodily fluids again to SAP. ing.

[0004] Flaff pulp such as known NBKP (softwood bleached kraft pulp) and NBSP (softwood bleached sulphite pulp) is generally used widely because of its high speed of absorbing liquids such as body fluids. However, in recent years, absorbers have become thinner, and the proportion of fluff pulp having a large volume has been reduced, and the proportion of SAP having a small volume and a large absorption capacity has tended to increase. The rate of absorption of urine or body fluid (hereinafter referred to as absorption rate) of a thin absorbent having a high ratio is low, which causes leakage.

Various methods have been proposed to solve these problems, for example, Japanese Patent Publication No. 5-71.
702 and JP-A-3-206174, etc.
Crosslinking the inside of the cellulose fiber to improve the compression recovery of the fiber, thereby increasing the absorption rate, but requiring a complicated chemical treatment of crosslinking the cellulose fiber. However, there is a problem that the cost of the product becomes high.

[0006] Further, in order to solve the problem of a reduction in the absorption rate of an absorbent article, it has been proposed to provide a diffusion layer between the top sheet and the absorber. For example, JP-A-59-
Japanese Patent Application Laid-Open No. 228001 discloses that a net-like structural member made of a hydrophobic elastic foam is disposed, and Japanese Patent Application Laid-Open No. 60-198152 discloses a diffusion sheet comprising a hydrophilic synthetic fiber and a hot-melt fiber. And the like. However, the diffusion sheet made of these net-like structural members and synthetic fibers has a high absorption speed, but has no ability to absorb the moisture of the top sheet, so that urine and body fluids remain on the top sheet and the dry touch property of the top sheet is poor. There is a problem that it is not good, which causes discomfort to the user and may cause skin irritation.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional absorbent articles and to improve the absorption rate for efficiently absorbing urine and body fluid from the topsheet to the absorber. The present invention provides an absorbent article that has a high speed, and allows SAP to efficiently absorb and hold urine and bodily fluid once absorbed in the absorber, thereby improving the effect of preventing leakage from the side edge or the edge of the absorber. is there.

[0008]

Means for Solving the Problems The present invention for solving the problems of the above-mentioned conventional absorbent articles includes the following inventions. (1) In an absorbent article having a liquid-permeable topsheet, a liquid-impermeable topsheet, and an absorber disposed between these two sheets, the absorber is mainly composed of pulp and a highly absorbent polymer. And the pulp layer constituting the absorber comprises a first pulp layer and a second pulp layer disposed at least on both edge measuring portions of the first pulp layer, An absorbent article, wherein the pulp layer is formed of thermomechanical pulp.

(2) The pulp layer constituting the absorber is
The absorbent article according to (1), comprising: a first pulp layer; and a second pulp layer disposed on at least both side edges of the first pulp layer. (3) The pulp layer constituting the absorber comprises a first pulp layer and a second pulp layer disposed adjacent to at least outer sides of both side edges of the first pulp layer. The absorbent article according to (1). (4) The thermomechanical pulp is 5-6 in the absorbent.
(1)-(3)
The absorbent article according to any one of the above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The absorbent article according to the present invention is characterized in that the pulp layer constituting the absorbent is a first pulp layer and a second pulp layer arranged on at least both side edges of the first pulp layer. The first pulp layer is made of softwood bleached kraft pulp (NBKP) which has been generally used for an absorbent body.
The second pulp layer is formed of thermomechanical pulp (hereinafter, sometimes abbreviated as TMP). In the absorbent article of the present invention having such a configuration, when a bodily fluid such as urine is absorbed by the absorbent body, the bodily fluid is diffused to the periphery by the first pulp layer having excellent absorption / diffusion properties. The second pulp layer made of TMP, which is disposed at the periphery of the first pulp layer, is not good in diffusivity but is excellent in liquid retention, and therefore bodily fluids such as urine diffused from the first pulp layer. Is retained in the second pulp layer and further absorbed by the SAP, so that leakage of urine and the like from the peripheral portion of the pulp layer is prevented. As described above, the absorbent article of the present invention has excellent absorbency and an excellent effect of preventing leakage from the periphery.

Hereinafter, the absorbent article of the present invention will be described in detail using a disposable diaper as an example with reference to the drawings, but the present invention is not limited thereto. FIG. 1 is a partially cutaway plan view showing a disposable diaper of the present invention. Figure 1
In the disposable diaper, the liquid-permeable topsheet 1
And a liquid-impermeable back sheet 2 and an absorber 3 disposed between the two sheets.
Further, the absorbent body 3 includes a first pulp layer 4 disposed at a longitudinal center portion of the diaper, and a second pulp layer 5 made of thermomechanical pulp disposed at both side edges of the first pulp layer 4. The superabsorbent polymer (not shown) is uniformly blended in each pulp layer.

FIG. 2 shows the disposable diaper shown in FIG.
It is sectional drawing which shows the state cut | disconnected along X 'line. FIG.
1, the absorber 3 is formed of a first pulp layer 4 and second pulp layers 5 arranged on both side edges on the first pulp layer. FIG. 3 is a cross-sectional view showing an example different from FIG. 2 and showing a state where the disposable diaper shown in FIG. 1 is cut along a line XX ′. In FIG. 3, the absorber 3 is
First pulp layer 4 arranged at the longitudinal center of the diaper
And a second pulp layer 5 disposed adjacent to the outside of both side edges of the first pulp layer.

In the present invention, the absorbent is basically composed of pulp and a superabsorbent polymer. However, if necessary, heat-fused fibers may be blended in the absorbent, and the absorbent may be wrapped in a tissue. There may be. The shape of the absorber is an hourglass type, a rectangular type, or the like, but an hourglass type provides better fit. The absorber comprises a first pulp layer and a second pulp layer disposed on at least both side edges of the first pulp layer, and the second pulp layer is formed by TMP.

The TMP used for the second pulp layer in the present invention is manufactured by a pulping method using a steam heating treatment and a refining treatment, and the fibrillation state of the fiber is suppressed by heating, pressing, and steaming conditions. be able to. Generally, in TMP, the chips are heated to a temperature that does not exceed the glass transition point of lignin, that is, the lignin softens, but still exists as a glassy state. In this case, the fibers are mainly cleaved between the primary membrane and the outer layer of the secondary membrane by refining, and the fiber surface becomes rough, resulting in a pulp containing many hydrophilic long fibers. Alternatively, pulp manufactured by a CTMP method in which chips are chemically treated and then refined under pressure can be used. Further, bleached BCTMP can also be used. The tree species used as the raw material may be coniferous or hardwood. The second pulp layer may be made of TMP alone, or may be mixed with other pulp as needed.

In the present invention, the proportion of TMP in the absorber is preferably 5 to 60% by weight.
More preferably, it is 0% by weight. TMP in this range
By mixing TMP, the strength of the fiber itself is high and the water retention is high, so when used as an absorber, the absorption performance is maintained without reducing the strength of the absorber after absorbing urine or body fluid It is possible to do. When the TMP contained in the absorber is less than 5% by weight, the absorption rate of the absorber is excellent, but the ability to retain urine and body fluid is insufficient, so that the effect of preventing leakage at the side edge of the absorber decreases. . on the other hand,
If the TMP contained in the absorber exceeds 60% by weight, the water retention of urine and body fluid is high, but the absorption rate and diffusivity are insufficient, and when a large amount of urine or body fluid is excreted, Because it is no longer absorbed by water, leaks are likely to occur.

In the present invention, for the first pulp layer, pulp conventionally used generally for an absorber can be used. As such a pulp, those having a fiber length of 5 mm or less obtained by defibrating a chemical pulp sheet or a mechanical sheet pulp are preferable. As pulp raw materials, in addition to conifers and hardwoods, straw, bamboo, kenaf For example, waste paper pulp or the like can be used.

As the liquid-permeable topsheet used in the present invention, nonwoven fabrics, woven fabrics, porous plastic films, porous foams, reticulated foams and the like made of polyethylene, polypropylene, and other thermoplastic fibers are used. In addition, natural fibers (for example, wood fibers, cotton fibers, etc.)
But it is also good, such as a combination of synthetic fibers and natural fibers,
Although it can be manufactured from a wide range of materials, in any case, the surface sheet is a portion that is in direct contact with the skin, and therefore may be any material that is soft and comfortable. Also,
When the material of the surface sheet is water repellent, a surface sheet subjected to a hydrophilic treatment is used.

As the liquid impermeable backing sheet used in the present invention, a liquid impermeable sheet made of polyethylene or the like is used. In particular, a plastic sheet that has many micropores that do not allow the passage of liquid but allows water vapor to pass, a vapor-permeable sheet obtained by adding a filler to a thermoplastic resin, or a nonwoven fabric outside these sheets It is preferable to use a composite sheet or the like in which the moisture inside the diaper is released to the outside and stuffiness and rash are prevented.

The superabsorbent polymer used in the present invention includes starch, cellulose, and synthetic polymer. That is, saponified starch-acrylic acid (salt) graft copolymer, starch-ethyl acrylate graft copolymer, saponified starch-methyl methacrylate graft copolymer, saponified starch-acrylonitrile graft copolymer Saponified starch-acrylamide graft copolymer, acrylic acid (salt) polymer, polyethylene oxide crosslinked with acrylic acid, crosslinked product of sodium carboxymethylcellulose, crosslinked product of polyvinyl alcohol-maleic anhydride reactant, etc. . Some of these have the ability to absorb urine, body fluid, and water that are 20 times or more their own weight, but it is preferable to use a synthetic resin-based sodium polyacrylate that has an absorption capacity that is 50 times or more their own weight. These superabsorbent polymers may be used alone or in combination of two or more. Further, the superabsorbent polymer may be in the form of powder or fiber, and the size is not particularly limited.

[0020]

The effects of the present invention will be described below in detail with reference to examples. In addition, the absorption rate, the amount of reversion, and the lateral leakage performance were evaluated using the samples of the examples and the comparative examples. The evaluation method of each characteristic is as follows. Absorption speed: 10 x 1 with a 1-inch diameter hole in the center
A 0 cm stainless steel plate (weighing about 600 g) was placed at the center of the sample, 50 ml of artificial urine was injected into the hole, and the time (second) required until it was absorbed was measured.
The measurement was repeated three times every minute. The composition of the artificial urine used is as follows. Urea 1.9% NaCl 0.8% CaCl ₂ 0.1% MgSO ₄ 0.1% H ₂ O 97.1%

The amount of reversion: 30 samples were measured for the absorption rate.
After standing for 10 minutes, a 10 × 10 cm filter paper (Advantech No. 63, manufactured by Toyo Roshi Kaisha, Ltd.) was placed in the center of the sample for 1 minute.
After stacking 0 sheets and allowing them to stand for 5 minutes under a load of 0.05 kg / cm ² , the increased weight of the filter paper was measured and defined as the amount of return (g). Lateral leakage performance: Artificial urine was injected at a rate of 7 ml / sec from the center of a 15 × 25 cm square absorber sample, and the time required for the artificial urine to leak from the lateral side edge of the absorber was measured. At this time, a fixing treatment was performed with a vinyl tape so as to prevent artificial urine from leaking from both longitudinal edges of the absorber sample.

Example 1 120 g / m ^{2 of} flocculent pulp composed of NBKP and 120 g / m of a superabsorbent polymer composed of sodium polyacrylate
A first pulp layer having a size of 15 × 25 cm was formed using a mixture of m ² uniformly, and then 70 g / m ^{2 of} TMP (Senibra) and 70 g of the above superabsorbent polymer
/ M ² was uniformly mixed, and ^second pulp layers of 5 × 25 cm were formed on both side edges of the first pulp layer to prepare an absorber. A surface sheet formed by wrapping the obtained absorbent body with a tissue and further applying pressure to a tension of 0.1 g / m ³ , and then formed of a 25 g / m ² nonwoven fabric made of a composite fiber of polypropylene / polyethylene,
A disposable diaper having an absorber having a cross-sectional shape as shown in FIG. 2 was produced by sandwiching between back sheets formed of a polyethylene film having a thickness of 25 μm. In this case, the proportion of TMP in the absorber is about 18% by weight.

Example 2 A disposable diaper was prepared in the same manner as in Example 1 except that the amount of the cotton-like pulp comprising TMP was changed to 150 g / m ² . In this case, the proportion of TMP in the absorber is about 25% by weight.

Example 3 120 g / m ^{2 of} flocculent pulp composed of NBKP and 120 g / m of a superabsorbent polymer composed of sodium polyacrylate
using what were uniformly mixed m ² to form a first pulp layer of the size of 8 × 25 cm, then using what were uniformly mixed TMP (CENIBRA Co.) 120 g / m ^2, the 3.5 × 2 on both sides of one pulp layer
An absorbent was made by placing a 5 cm second pulp layer adjacent to it. After wrapping the obtained absorbent body with a tissue and pressing it to a tension of 0.1 g / m ³ , a surface sheet formed of a 25 g / m ² nonwoven fabric made of a composite fiber of polypropylene / polyethylene, Sandwiched between the back sheets formed by a 25 μm polyethylene film,
A disposable diaper having an absorber having a sectional shape as shown in FIG. 3 was produced. In this case, TM occupied in the absorber
The proportion of P is about 23% by weight.

Example 4 A disposable diaper was prepared in the same manner as in Example 3 except that the amount of the cotton-like pulp comprising TMP was changed to 200 g / m ² . In this case, the proportion of TMP in the absorber is 33% by weight.

Comparative Example 1 A disposable diaper was prepared in the same manner as in Example 1 except that a second pulp layer was formed using NBKP instead of TMP. Comparative Example 2 A disposable diaper was produced in the same manner as in Example 1 except that the second pulp layer was formed using GP (crushed wood pulp) instead of TMP.

Comparative Example 3 A disposable diaper was prepared in the same manner as in Example 3 except that a second pulp layer was formed using NBKP instead of TMP. Comparative Example 4 A disposable diaper was produced in the same manner as in Example 3, except that the second pulp layer was formed using GP (crushed wood pulp) instead of TMP.

Table 1 shows the evaluation results of the characteristics of the disposable diapers of the examples and comparative examples. As is clear from Table 1, the disposable diaper of the present invention in which the TMP is disposed on both side edges of the pulp layer constituting the absorbent body in each of the examples is excellent in absorption performance and leaks from the absorbent side edges. While the resistance characteristics were excellent, the comparative example not using TMP was inferior in the leakage resistance characteristic from the side edge of the absorber, and the effect of the present invention was confirmed.

[0029]

[Table 1]

[0030]

As described above, the absorbent article of the present invention has excellent absorption characteristics and an excellent effect of preventing leakage from the peripheral edge.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing a state where the disposable diaper shown in FIG. 1 is cut along a line XX ′.

3 is a cross-sectional view showing an example different from FIG. 2 and showing a state where the disposable diaper shown in FIG. 1 is cut along a line XX ′.

[Explanation of symbols]

 1. Top sheet 2. Back sheet 3. Absorber 4. First pulp layer5. Second pulp layer 6. 3d gather

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3B029 BA05 BA15 4C003 AA18 4C098 AA09 CC03 CE06 DD06 DD23 DD27

Claims (4)

[Claims] 1. An absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber disposed between these two sheets, wherein the absorber is pulp and a highly absorbent polymer. And a pulp layer constituting the absorber comprises a first pulp layer and second pulp layers disposed on at least both side edges of the first pulp layer, An absorbent article characterized in that the pulp layer is formed of thermomechanical pulp. 2. A pulp layer constituting the absorber, comprising:
The absorbent article according to claim 1, comprising a pulp layer of a first pulp layer and second pulp layers disposed on at least both side edges of the first pulp layer. 3. The pulp layer constituting the absorber is a first pulp layer.
The absorbent article according to claim 1, comprising a pulp layer of a first pulp layer and a second pulp layer disposed adjacent to at least outer sides of both side edges of the first pulp layer. 4. The absorbent article according to claim 1, wherein the thermomechanical pulp is contained in the absorbent at 5 to 60% by weight.