JPH06327711A - Absorbable article - Google Patents

Abstract

PURPOSE:To minimize the uncomfortable feel given to the skin and to provide an excellent wearing feel having a soft and tight fit feel by rapidly absorbing liquid having intricate properties, for example, liquid having viscosity and liquid contg. solid components, without generating lateral leakage. CONSTITUTION:This absorbable article consists of a liquid permeable front surface sheet, an absorptive layer which absorbs and holds the liquid and a liquid impermeable liquidproof sheet which is disposed on the rear surface of the absorptive layer. A knitting-like diffusion sheet for rapidly diffusing the liquid is interposed between the front surface sheet and absorptive layer of the absorbable article described above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorbent article, and more specifically, it is disposable such as sanitary napkins and disposable diapers, and is complicated in that it is viscous and contains solids. The present invention relates to an absorbent article having excellent absorbency of liquid having various properties.

[0002]

2. Description of the Related Art Generally, absorbent articles typified by sanitary napkins, disposable diapers and the like are hydrophobic non-woven fabrics such as polyolefins for quickly transferring liquid to an absorbent layer and suppressing discomfort to the skin. A surface sheet that has been subjected to a hydrophilic treatment, an absorption layer that is a combination of a sheet material such as cotton pulp or a tissue such as a tissue for absorbing and holding the liquid, and a polymer absorber, and the liquid. And a liquid-proof sheet made of a polyethylene film or the like disposed on the back surface of the absorbent layer for preventing the leakage of the liquid to the outside.
In such absorbent articles, (1) the liquid is quickly permeated to prevent side leakage, and (2) the liquid absorbed by the absorbent layer does not get wet again on the surface (hereinafter referred to as “wetting resistance "Performance") is the most required performance. Further, it is also an important required performance that a feeling of stuffiness and a feeling of foreign matter at the time of wearing are minimized and an excellent feeling of wearing is provided.

Various studies have hitherto been made to satisfy such performance. For example, Japanese Patent Laid-Open No. 62-12506
JP-A No. 62-181041 discloses that a perforated non-woven sheet is used as a top sheet to improve the absorbability of menstrual blood and the like, and JP-A No. 62-181041 discloses a liquid-permeable non-woven sheet. It is disclosed that the average inter-fiber distance of (3) is added to improve the permeability of a liquid, particularly a highly viscous liquid. But,
Viscosity such as menstrual blood and highly viscous liquids, or liquids containing solids are difficult to be absorbed by the absorbent layer, so even if the permeability of the surface sheet is excellent, the absorption rate of the absorbent layer cannot catch up, There was a limit to the improvement in absorption. In addition, JP-A-4
JP-A-89053 discloses that a diffusion sheet made of hydrophilic fibers is used between a topsheet and an absorbent layer to suppress liquid return to the surface and lateral leakage of liquid. However, since this diffusion sheet is composed of hydrophilic fibers, the fibers themselves are absorbed when diffusing a liquid, and if body pressure or the like is applied, they may seep into the surface sheet and get wet again.

In this way, the side leakage of the absorbent article is suppressed,
In order to improve the absorbability and the resistance to wetting back, improvements have been made to the surface sheet and the absorbent layer including the diffusion sheet, but the present situation is that satisfactory ones have not been obtained.
Regarding the improvement of the feeling of wearing, it has been attempted to improve the feeling of stuffiness by using a moisture-permeable film for the liquid-proof sheet such as sanitary napkins and disposable diapers on the market, but there is a limit because there is a re-wetting on the surface. . Also, with sanitary napkins, we are trying to reduce the feeling of foreign matter when wearing it by thinning the sanitary napkin itself, but on the contrary, it is hard like paper and does not feel close to the body, leaving a stiff foreign body feeling, The current situation is that a comfortable wearing feeling is not obtained.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to cause side leakage of liquids having complicated properties such as viscosity and solid content. An object of the present invention is to provide an absorbent article having an excellent feeling of wearing that absorbs quickly without any discomfort, minimizes discomfort given to the skin, and has a soft and close contact feeling.

[0006]

The absorbent article of the present invention comprises:
An absorbent article comprising a liquid-permeable surface sheet, an absorbent layer that absorbs and holds liquid, and a liquid-impermeable liquid-proof sheet disposed on the back surface of the absorbent layer, wherein the surface sheet and the absorbent layer A knitted diffusion sheet for quickly diffusing the liquid is interposed between the two.

As the diffusion sheet used in the present invention, any knitted sheet produced by a warp knitting machine, a circular knitting machine or a flat knitting machine may be used. Further, these knitted fabrics may be obtained by a single-row needle bed (single) or a double-row needle bed (double) knitting machine. Furthermore, the knitted fabric used for the diffusion sheet is preferably the knitted fabric shown below, because the liquid is quickly diffused from the surface sheet and transferred to the absorption layer. The material of the knitted fabric may be any of synthetic fibers, natural fibers, regenerated fibers, etc., but at least on the side facing the surface sheet in order to prevent the absorbed liquid from returning to the surface. The presence of hydrophobic fibers is preferred. The fineness of the fibers used in the knitted fabric is not particularly limited, but it is preferable to use ultrafine fibers having a low fineness in terms of flexibility, absorbability, diffusibility and the like. The cross-sectional shape of the fiber is not particularly limited, but a modified cross-section such as silk is preferable from the viewpoint of diffusion transferability. Although not particularly limited to the density of the knitted fabric, the liquid has excellent diffusibility, the diffused liquid is rapidly transferred to the absorption layer, and from the viewpoint of maintaining flexibility and shape retention,
The fiber content is preferably 2.0 to 50.0%. Here, the fiber content is the ratio of the fiber per unit area occupied by the following formula. Fiber content (%) = [Basis weight (g / m ² ) × 10 ^-4 / (Thickness (cm) × Fiber density (g / cm ³ ))] × 100 The thickness of the knitted fabric is the re-wetting of the liquid. From the viewpoint of the wearability and the feeling of wearing, the value when measured at a contact pressure of 100 g / cm ² is 0.
It is preferably 1 to 5.0 mm.

In the present invention, since the above-mentioned knitted sheet is used as the diffusion sheet between the topsheet and the absorbent layer, the liquid that has permeated the topsheet can be quickly diffused to promote the absorption. In addition, since the absorbent layer does not adhere to the surface sheet, wetting back of the liquid once absorbed is suppressed, and due to the cushioning characteristic of the knit, flexibility is maintained even with a thin napkin, and it is easy to adhere to the body when worn, An absorbent article having excellent wearing feeling can be obtained.

The surface sheet used in the present invention includes:
It has a function of rapidly feeding a liquid to the absorption layer, and includes, for example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polyamides such as nylon 6, nylon 6,6, acrylics such as polyacrylonitrile, and rayon. Cellulose such as cotton, cotton or the like, or non-woven fabric such as a mixture thereof, perforated film and the like. Among these, a non-woven sheet using hydrophobic fibers and a hydrophilic non-woven sheet that has been subjected to hydrophilic treatment with a surfactant, etc. or a hydrophobic perforated film not only rapidly feeds the liquid into the absorption layer, but also suppresses wetting back. It is preferable for producing the effect. As the non-woven fabric sheet, a long fiber non-woven fabric sheet produced by a spun bond method or the like, a short fiber non-woven fabric sheet produced by a heat bond method, a thermal bond method or the like is used.

The absorbing layer used in the present invention has a function of absorbing and holding a large amount of liquid and not returning the liquid once absorbed to the surface again. As the absorption layer, wood pulp,
Cellulose cotton, cotton, rayon fiber-like cotton-like material, tissue, rayon non-woven fabric sheet-like material or a combination of these with a polymer absorber or the like is preferably used, but one that further improves the absorbency. However, it is not limited to these. As the waterproof sheet used in the present invention, a film having a function of preventing liquid from leaking to the outside and a film of polyolefin, polyester, polyamide, acrylic, or the like is used. From the viewpoint of suppressing stuffiness when worn, it is preferable to use a moisture permeable sheet or the like made of a microporous membrane such as polyethylene.

[0011]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. [Example 1] A polypropylene spunbonded non-woven fabric sheet having a basis weight of 20 g / m ² and a thickness of 0.2 mm was treated with polyoxyethylene octyl phenyl ether (Triton X-100 (registered trademark) manufactured by Toho Chemical Co., Ltd.) which is a water-permeable agent. After that, a hole having a hole diameter of 1.5 mm and a hole area ratio of 7.2% was formed into a perforated nonwoven fabric, which was used as a surface sheet. Also, using a 22-gauge double circular knitting machine using false-twisted yarn of polyethylene terephthalate 150d / 96f, a thickness of 1.
1 mm, basis weight 240 g / m ² , density 27 courses / inch, 31 wales / inch, fiber content 15.8%
A circular knit, which is a knitted fabric having a smooth structure, was produced and used as a diffusion sheet. The surface sheet and the diffusion sheet obtained above, an absorption layer (a product manufactured by Kao Corporation, consisting of wood pulp and a polyacrylic acid type polymer absorber, trade name "Laurier", thickness 3 mm) and a liquid-proof sheet (Moisture permeable polyethylene film, thickness 0.3 mm) were sequentially laminated to obtain a sanitary napkin.

[Example 2] In Example 1, as the surface sheet, short fibers having a cut length of 20 mm, which consisted of two components of polyethylene and polypropylene, were carded and thermally bonded with a basis weight of 20 g / m and a thickness of 0.2 mm ² . A sanitary napkin was obtained in the same manner as in Example 1 except that a fibrous nonwoven fabric was used. [Example 3] In Example 1, as a surface sheet, a polyethylene film having a thickness of 0.03 mm was used, and a pore diameter was 0.5 m.
A sanitary napkin was obtained in the same manner as in Example 1 except that a perforated film having a hole area ratio of 17.6% in m was used.

Example 4 Polyethylene terephthalate 50d / 350 was used as the diffusion sheet in Example 1.
Using a 28 gauge single tricot machine using the ultrafine fibers of f, a half structure with a thickness of 0.2 mm, a basis weight of 105 g / m ² , a density of 58 courses / inch, 40 wales / inch, and a fiber content of 34.9%. A sanitary napkin was obtained in the same manner as in Example 1 except that a certain tricot knitted fabric was used. [Example 5] A sanitary napkin was obtained in the same manner as in Example 1 except that the short fiber nonwoven fabric used in Example 2 was used as the surface sheet and the tricot knitted fabric used in Example 4 was used as the diffusion sheet. [Example 6] A sanitary napkin was obtained in the same manner as in Example 1 except that the perforated film used in Example 3 was used as the surface sheet and the tricot knitted fabric used in Example 4 was used as the diffusion sheet.

[Comparative Example 1] In Example 1, as a diffusion sheet, carded rayon short fibers with a cut length of 20 mm were carded and needle punched to give a sheet-like short sheet having a basis weight of 40.0 g / m ² and a thickness of 0.3 mm. A sanitary napkin was obtained in the same manner as in Example 1 except that a fibrous nonwoven fabric was used. [Comparative Example 2] In Comparative Example 1, a sanitary napkin was obtained in the same manner as in Comparative Example 1 except that the short fiber nonwoven fabric used in Example 2 was used as the surface sheet. [Comparative Example 3] Comparative Example 1 except that the perforated film used in Example 3 was used as the topsheet in Comparative Example 1.
A sanitary napkin was obtained in the same manner as. [Comparative Examples 4, 5, 6] Sanitary napkins were prepared in the same manner as in Example 1, Example 2 and Example 3 except that the diffusion sheet was not used in Example 1, Example 2 and Example 3. Obtained.

[Test Example] Examples 1 to 6 and Comparative Examples 1 to 1
The performance of the sanitary napkin obtained in No. 6 for liquid absorbency, anti-wetting resistance and wearing feeling was evaluated by the following methods, and the results are summarized in Table 1. (1) Liquid absorption: Absorption time (seconds) of a certain amount of liquid was measured to compare the liquid absorption. That is, 5 cc of the test solution is dropped on the surface sheet, and the time until the light on the surface of the test solution disappears is measured. If the absorption time is 4 seconds or less, the liquid is absorbed before spreading laterally It was evaluated that it is excellent in leak prevention and starts to flow before being absorbed for 10 seconds or more to cause side leakage.

(2) Wetting reversion resistance: Wetting reversion rate after liquid absorption was measured to compare the wetting reversion characteristics which is the largest cause of discomfort. That is, 5 cc of the test liquid was dropped on the surface sheet, and the liquid was absorbed by pressurizing for 5 minutes, and then the filter paper was placed on the surface sheet and pressed for 5 minutes again. The wet restitution rate of 5% or less was defined as a range in which discomfort can be suppressed, and 10% or more was evaluated as being considerably uncomfortable. Wetting-back rate (%) = (test liquid g that has returned to the filter paper g) / (dripping test liquid g) x 100 (3) Feeling of wear: The elasticity of compression is measured to give the feeling of wearing an absorbent article. Simulated and compared the feeling of wearing.
That is, a compression tester KES-FB3 (manufactured by Kato Tech) was used to measure the compression work amount per unit area. The larger this value, the more elastic and soft the compression work amount is 10 g.
I feel the softness when worn in the f · cm / cm ² or more, 6gf ·
When cm / cm ² or less, it was evaluated that it did not adhere to the body and there was a feeling of foreign matter. The test liquids of (1) and (2) were prepared using menstrual blood as a model. That is, as a result of examining menstrual blood, it was found that it has a viscosity of about 10 cps and contains a small amount of solid matter such as cell walls.
A small amount of wheat flour was dissolved in the PVA aqueous solution to prepare a test solution.

[0017]

[Table 1]

From Table 1, it can be seen that in Examples 1 to 6, the liquid absorption time was 4 seconds or less, the liquid absorption property was excellent, and the liquid was quickly absorbed without causing lateral leakage. In addition, the wetting regain rate is all 5% or less, excellent rewetting resistance, less discomfort due to rewetting of liquid once absorbed, and short fiber non-woven fabric that was conventionally considered to have poor rewetting resistance Also, it can be seen that the use of a knitted diffusion sheet significantly improves the wetting resistance. Furthermore, since the compression work amount reached approximately 10 gf · cm / cm ² , it was found that the wear feeling is excellent, the body fits comfortably and the foreign body feeling is small.

[0019]

According to the present invention, by using a knitted diffusion sheet between the topsheet and the absorbent layer, a liquid having complicated properties such as viscosity and solid content can be obtained. It is possible to obtain an absorbent article that absorbs quickly without causing side leakage, minimizes discomfort on the skin, and has an excellent wearing feeling. Absorbent articles of the present invention, in addition to sanitary napkins, disposable diapers, etc., surgical dressing materials and breast pads, etc., absorbent pads for body fluids, absorbent sheets, etc. It is used for applications such as absorbent pads for special liquids such as oil and various wipers, and it can be used in various fields other than this.

Claims (1)

[Claims] 1. An absorbent article comprising a liquid-permeable topsheet, an absorbent layer that absorbs and retains liquid, and a liquid-impermeable liquid-proof sheet disposed on the back surface of the absorbent layer,
An absorbent article, wherein a knitted diffusion sheet for quickly diffusing a liquid is interposed between the surface sheet and the absorbent layer.