JP2876113B2 - Absorbent articles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates generally to disposable absorbent articles such as disposable diapers, sanitary napkins, pads for incontinent persons, and the like. More specifically, the present invention relates to an absorbent article that is excellent in the permeability and diffusion of the liquid to be absorbed in the absorber layer, has a good dry feeling, generates less leakage, and is comfortable for the user.

[0002]

2. Description of the Related Art Various improvements have been proposed for the purpose of improving the performance of absorbent articles, for example, improving the absorption speed of urine and blood, improving the dry feeling after absorption, and reducing the leakage. . Most of these proposals are based on modification of liquid-permeable topsheets and nonwoven fabrics (Japanese Patent Laid-Open No. 58-60068).
JP, JP-A-1-148879, JP-A-2-1-1
No. 69774), the use of a water-absorbent resin having specific performance and physical properties, the arrangement of the water-absorbent resin in the absorber layer, the use of a hydrophilic diffusion layer made of a material such as a nonwoven fabric or water-absorbing paper, and absorption. The present invention relates to an embossing method of a body layer, and there is hardly any improvement proposal focusing on the modification of the absorber layer itself containing a water absorbent resin. The reason is that the conventional disposable diaper forms the absorber layer with a highly hydrophilic material such as fluff pulp, absorbent paper, and water absorbent resin.

[0003]

In recent years, there has been a tendency that absorbent articles such as disposable disposable diapers and sanitary napkins are worn for a long time with the improvement of performance. Furthermore, in the case of disposable diapers, the ratio of the water-absorbent resin / fiber base material tends to increase as the thickness becomes thinner. In response to these trends, conventional cellulose fibers (eg, fluff pulp, absorbent paper, etc.)
In the absorbent layer composed of a water-absorbent resin and a water-absorbent resin, it is possible to apply the water-absorbent resin between the pulp layer and the absorbent paper, or to mix it with the pulp. Retention and the integrity of the water-absorbent resin / fibrous base material cannot be obtained. In other words, hydrophilic cellulose fibers that absorb and retain liquids (urine, blood, etc.) by physical capillarity are easily deformed when external force is applied by the movement of the wearer at the time of absorption or in the wet state after absorption. However, there has been a problem that the integrity with the water-absorbent resin / fiber base material is impaired, resulting in generation of leakage and a decrease in dry feeling. Proposal to prevent the absorber layer from being deformed when wet, that is, to provide the absorber layer with an elastic function that can restore its original shape even if the absorber layer is compressed or twisted by external force. Has been made. For example, there is an attempt to form an absorber layer by sandwiching a water-absorbing resin between sheet-like materials made of synthetic fibers. By this method, the shape retention when wet can be improved to some extent, but when the amount of the water-absorbent resin increases, the water-absorbent resin sandwiched between the fiber sheet-like materials forms a gel layer after absorption. However, there is a problem in that the gel layer is displaced by an external force, thereby deteriorating the integrity with the water-absorbent resin gel / fiber substrate and leading to generation of leakage.
Furthermore, since synthetic fibers are poor in hydrophilicity, there is a problem that liquid permeability and diffusivity are reduced. There is also an attempt to improve the shape retention of the absorber layer by mixing and dispersing a water-absorbing resin inside a fiber base material using a heat-fusible synthetic fiber and fluff pulp in combination, followed by heat treatment. However, although improvement in shape retention is recognized by this method,
Since the hydrophilicity of the absorbent layer decreases as the ratio of the synthetic fibers increases, there arises a problem that the liquid permeability and the diffusivity decrease as compared with a conventional absorbent layer composed of cellulose fibers alone.

[0004]

Means for Solving the Problems The present inventors have excellent shape retention when wet and excellent integration with a water absorbent resin / fiber base material.
In addition, the present invention has been thoroughly studied in order to obtain an absorbent article that has good liquid permeability and diffusivity, has excellent surface dry feeling after absorption, has reduced leakage, and can be used comfortably for a long time. Reached.

That is, the present invention relates to an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber layer provided between both sheets, wherein the absorber layer swells in water. An absorbent layer composed of a synthetic fiber (a) and a water-absorbent resin (c) which is not used, or an absorbent layer composed of the synthetic fiber (a), the cellulosic fiber (b) and the water-absorbent resin (c) The ratio between (a) and (b) is (100 to 2) on a weight basis.
0): (0 to 80), the amount of (c) is 25 to 75% by weight based on the total weight of (a), (b) and (c), and the absorbent layer is made of poly 25 content of oxyethylene groups
Polyoxyalkylene-modified silicone-based surfactant (d1) and / or HLB of 8 to 1% by weight
An absorbent article obtained by treating with a surfactant (d) selected from the non-silicone surfactants (d2).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, examples of synthetic fibers (a) which do not swell in water include polyolefin fibers (eg, polyethylene fibers, polypropylene fibers, polyethylene / polypropylene composite fibers), polyester fibers ( For example, thermoplastic fibers such as polyethylene terephthalate fibers, polyethylene terephthalate / polyethylene isophthalate copolymer composite fibers), polyolefin / polyester composite fibers, polyamide fibers, and polyacrylonitrile fibers. Preferred among these synthetic fibers are polyolefin-based fibers, polyester-based fibers and these are conjugated fibers, and more preferably, sheath fibers in that they are applied to disposable diapers and the like and have excellent shape retention after liquid absorption. It is a composite heat-fusible polyolefin fiber such as a core type, an eccentric type, and a parallel type. The length and thickness of the synthetic fiber are not particularly limited, and can be suitably used as long as the length is usually in the range of 1 to 200 mm and the thickness is in the range of 0.1 to 100 denier. The shape is not particularly limited as long as it is fibrous, and is in the form of a web, a thin cylinder, a cut split yarn,
Staple shape, filament shape and the like are exemplified.

The cellulosic fibers (b) used as required include those conventionally used in absorbent articles, such as ordinary fluff pulp and floc pulp. There are no particular restrictions on the raw material (b), such as conifers or hardwoods, the production method (chemical pulp, semi-chemical pulp, CTMP, etc.), the bleaching method, and the like.

The ratio of (a) to (b) is usually (100-20) :( 0-80), preferably (100-25) :( 0-75), more preferably, on a weight basis. (1
00 to 30): (0 to 70). The amount of (a) is 20
When the amount is less than the weight percentage, the shape retention of the absorber layer is reduced.
As a result, when an external force is applied by the movement of the wearer during or after absorption of the liquid, and the absorber layer is compressed or twisted, it causes generation of moisture and a reduction in dry feeling.

In the present invention, the water-absorbing resin (c) includes, for example, a starch-acrylate copolymer cross-linked product,
Crosslinked polyacrylate, self-crosslinked polyacrylate, saponified acrylate-vinyl acetate copolymer crosslinked product, crosslinked isobutylene / maleic anhydride copolymer, crosslinked polysulfonate, modified cellulose derivative ,
Crosslinked polyethylene oxide and the like can be mentioned. Preferably, it is capable of absorbing and holding a large amount of liquid by ionic osmotic pressure, and has a low water separation even when a load or external force is applied. It is a crosslinked polymer. The type of salt is not particularly limited, but is usually an alkali metal salt such as sodium or potassium. Further, a resin in which the vicinity of the surface of the particulate water-absorbent resin is further surface-crosslinked can be suitably used according to the present invention. Note that, unlike the water-soluble resin, the water-absorbent resin is insoluble in water and is water-swellable.

The water-absorbent resin (c) has a normal pressure absorption of 40 g / g or more in physiological saline and a pressure absorption of 20 g / g.
Above, those having a gel elastic modulus of 20,000 dynes / cm ² or more are preferable, and more preferably, the normal pressure absorption amount is 45 to 45.
75 g / g, pressure absorption of 25 to 50 g / g, gel elasticity of 30,000 to 200,000 dynes / cm ² , particularly preferably normal pressure absorption of 50 to 75 g / g, pressure absorption of 30-50 g / g, gel elastic modulus 35,000-2
It is of 0.00000 dynes / cm ² . By using a water-absorbing resin having a normal pressure absorption of 40 g / g or more,
The required absorption characteristics can be achieved only by using a very small amount of the water-absorbing resin, which is economical. In addition, the pressure absorption amount is 20 g /
By using a water-absorbent resin of g or more, the required absorption characteristics can be achieved only by using a small amount of the water-absorbent resin, which is economical. The gel elasticity is 20,000 dynes / cm
^{When two} or more water-absorbing resins are used, the swollen gel that has absorbed the liquid is not too soft, the swollen gel is not easily deformed by a load or an external force, and the swollen gels adhere to each other to cause blocking, and liquid penetration or diffusion. It is preferable because there is no possibility of obstruction. In addition, normal pressure absorption amount for physiological saline, pressure absorption amount,
The gel modulus is a value measured by the following method. Normal pressure absorption: 1 made of 250 mesh nylon net
1 g of a water-absorbent resin is placed in a tea bag having a size of 0 cm × 20 cm, immersed in excess physiological saline (aqueous sodium chloride solution having a concentration of 0.9% by weight) for 30 minutes, and then vertically pulled up and drained for 15 minutes. , The increased weight was determined, and this value was taken as the normal pressure absorption amount. Amount of pressure absorption: Cylindrical plastic tube (inner diameter 30 mm, height 6) with 250 mesh nylon mesh stuck on the bottom
0mm) into 0.1g of water-absorbent resin and spread evenly.
An outer diameter of 30 m is applied on this so that a load of 20 g / cm ² is applied.
Put a weight of m. Petri dish with 60 ml of physiological saline (diameter: 12 cm) with the nylon mesh side facing down
Immerse in. The value of 10 times the increased weight after immersion for 30 minutes was defined as the pressure absorption. Gel elastic modulus: 40 ml of artificial urine is added to 1 g of water-absorbent resin to prepare a 40-fold absorbent gel. 0.1 g of the gel is placed at the center of a support table of a creep meter (manufactured by Yamaden Corporation). The cylinder is then lowered from the top to compress the gel to a thickness of 0.3 mm. The stress (F) during compression and the cross-sectional area (S) of the compressed gel were measured, and
The stress at the time of compression per unit area was calculated, and this value was defined as the gel elastic modulus. Gel modulus (dyne / cm ² ) = (F × 980) / S

The shape of the water-absorbent resin (c) is not particularly limited, and any of a particulate form and a fibrous form can be suitably used. Preferably particulate (eg, granular, granular,
Granulated, scaly, massive, pearl-like, etc.). When the water-absorbent resin is in the form of particles, the average particle diameter is 150.
About 700 μm. Preferably 200-600μ
m, especially 250 to 500 μm. Average particle size 150
Particles of a water-absorbent resin having a diameter of not less than μm are preferable because gel blocking is less likely to occur upon contact with a liquid. Further, the problem of the water absorbent resin coming off from the absorber layer does not easily occur, which is preferable. On the other hand, if the average particle size exceeds 700 μm, the absorption rate becomes extremely slow. Further, when the average particle size is 700 μm or less, it is preferable that when touching the surface of the disposable diaper, a foreign particle sensation due to coarse particles is not felt and a problem that coarse particles pierce the back sheet does not occur.

The amount of the water-absorbent resin (c) is (a), (b)
It is usually from 25 to 75% by weight, preferably from 30 to 70% by weight, especially from 35 to 70% by weight, based on the total weight of (c) and (c). If the amount of (c) is less than 25% by weight, the synthetic fiber (a) does not have the ability to absorb water and swell, so that it is necessary to increase the thickness of the absorber layer in order to secure a necessary absorption capacity, and it becomes impossible to reduce the thickness. On the other hand, if the amount of (c) exceeds 75% by weight, the water-absorbent resin and the fibrous base material cannot be integrated, resulting in a problem in shape retention.

Water absorbent resin per absorbent article (c)
Is not particularly limited. For example, in the case of disposable paper diapers, the amount is usually 5 to 20 g. When it is called a thin diaper, it is usually 7 to 20 g, preferably 8 to 20 g. If it exceeds 20 g, a large amount of the fiber base must be used in order to secure the integrity between the water-absorbent resin and the fiber base, which is uneconomical. Although the above is an example of a disposable disposable diaper, when the absorbent article is a sanitary napkin, a pad for incontinent persons, or the like, the amount may be smaller than the above amount depending on the purpose and size of the article.

Among the surfactants (d), examples of the polyoxyalkylene-modified silicone-based surfactant (d1) include: polyoxyethylene-modified dimethylpolysiloxane, polyoxyethylene-polyoxypropylene block or A random copolymer-modified dimesyl polysiloxane, a dimethyl polysiloxane modified with a polyoxyethylene having a C1 to C12 alkyl group at a terminal, a polyoxyethylene having a C1 to C12 alkyl group at a terminal -Dimethylpolysiloxane modified with a block or random copolymer of polyoxypropylene,-The above polyoxyalkylene modification of a dimethylpolysiloxane derivative having an amino group, an epoxy group, etc. at the terminal and / or inside the molecule of the dimethylpolysiloxane Things It is below. Preferred are polyoxyethylene-modified dimethylpolysiloxane, polyoxyethylene.
Polyoxypropylene block or random copolymer-modified dimesylpolysiloxane is more preferable, and polyoxyethylene-modified dimethylpolysiloxane is more preferable because it can be industrially obtained at low cost. Although the molecular weight of the polyoxyalkylene-modified silicone surfactant (d1) is not particularly limited, it is generally 500 to 10,
000, preferably 500-5,000, especially 500-
3,000. When the molecular weight is 500 or more, it is economical because it is not necessary to use a large amount of (d1) to achieve good liquid permeability and diffusion in the absorber layer. In addition, the molecular weight is 10,000
When it is below, the viscosity is not too high and uniform treatment is facilitated. Therefore, there is no fear that an extremely large amount of solvent is required to adjust (d1) to an appropriate viscosity, and a step of removing the solvent is not particularly required, so that it is efficient. Further, the content of the polyoxyethylene group of the polyoxyalkylene-modified silicone surfactant (d1) can be variously changed according to the desired degree of hydrophilicity.
Usually 25 to 75% by weight, preferably 30 to 70% by weight,
In particular, it is 40 to 60% by weight. The ratio of the oxyethylene group to the oxypropylene group is not particularly limited as long as the content of the polyoxyethylene group is within the above range.
0-50): (0-50), preferably (100-6)
0): (0 to 40). When the content of the polyoxyethylene group is 25% by weight or more, there is no decrease in hydrophilicity,
When the absorber layer is treated, good liquid permeability and diffusivity can be obtained, which is preferable. Further, when the content of the polyoxyethylene group is 75% by weight or less, the water solubility is not too strong, and the effect of maintaining the liquid permeability and the diffusibility of the liquid with respect to several times of liquid absorption can be maintained.

Examples of the non-silicone surfactant (d2) having an HLB of 8 to 14 include: ethylene oxide adducts of higher alcohols (polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, etc.)・ Ethylene oxide adduct of alkylphenol (polyethylene nonylphenyl ether, etc.) ・ Polyoxyethylene monofatty acid ester (polyoxyethylene monooleate, polyoxyethylene monostearate, polyoxyethylene monolaurate, etc.) ・ Polyethylene glycol diester (Polyoxyethylenediolate, polyoxyethylene distearate,
Polyoxyethylene dilaurate), ethylene oxide adducts of polyhydric alcohol fatty acid partial esters (sorbitan monooleate (EO 5 mol), sorbitan monostearate (EO 4 mol),
Sorbitan monolaurate (EO4 mol)), sorbitan monolaurate and the like. Here, EO means ethylene oxide, and the number of moles in parentheses means the number of moles of EO added. Also, a mixture of these can be used. Preferred among the non-silicone surfactants (d2) are HL
B is a nonionic surfactant of 9 to 13. here,
HLB is a balance between hydrophilicity and lipophilicity of a surfactant, and can be controlled by the number of moles of ethylene oxide added and the molecular weight of polyethylene glycol.
The surfactant (d) is selected from (d1) and / or (d2), and (d1) and (d2) can be used in combination.

The treatment amount of the surfactant (d) can be variously changed according to the ratio of (a) to (b), the type of (a), the absorption characteristics of (c), and the like. .01-
5% by weight, preferably 0.02 to 2% by weight, especially 0.0%
It is 3 to 1% by weight. When the treatment amount is 0.01% by weight or more, the effect of improving the liquid permeability and diffusivity is excellent, which is preferable. Further, even when the treatment is performed in an amount exceeding 5% by weight, the performance is not changed from the case where the treatment is performed in the range of 0.01 to 5% by weight. It is preferable that the content is 5% by weight or less without causing stickiness.

The method of applying the water-absorbent resin (c) to a fiber base comprising a synthetic fiber (a) and optionally a cellulosic fiber (b) to obtain an absorber layer is as follows:
A method of simultaneously mixing (a), (b) and (c),
(2) a method of mixing (a) and (b) in advance and then mixing (c); (3) a method of mixing (a) with a mixture of (b) and (c); 4) In (b),
A method of mixing a mixture of (a) and (c), (5) (a)
A method of separately mixing (b) and (c), (6)
A method in which a mixture of (a) and (b) is laminated, (c) is sprayed thereon, and a mixture of (a) and (b) is further laminated and sandwiched. In these methods, (b) is an optional component used as needed. Preferred methods are the methods (1), (2) and (5). The apparatus used for these methods is not particularly limited, and an ordinary apparatus can be used.

The thus-prepared absorber layer is subjected to a heat treatment to finish the absorber layer having excellent shape retention when wet. There is no particular limitation on the method of heat treatment,
For example, a method of treating with hot air, a method of passing through a heating roll, and a method of irradiating infrared rays are exemplified. The temperature and time of the heat treatment may be determined by selecting conditions under which (a) develops adhesive strength and adheres to each other.
It can be arbitrarily selected in consideration of the usage amount of (a), the production speed of disposable diapers, and the like. Usually, the temperature of the heat treatment is 8
It is 0-250 degreeC, Preferably it is 90-200 degreeC, More preferably, it is 100-180 degreeC. Heat treatment temperature 8
By setting the temperature to 0 ° C. or higher, there is no need to lengthen the heating time, so that the heating treatment can be performed sufficiently without using a large-sized heating device, and it is economical. In addition, the production speed of the absorbent article is also preferable without decreasing. Further, it is preferable that the heat treatment temperature is 250 ° C. or higher, since there is no possibility of causing thermal deterioration of (b) and (c). Regarding the heating time, it is sufficient to select a condition in which (a) expresses adhesive strength and adheres to each other.
It can be arbitrarily selected in consideration of the type of (a), the amount of (a) used, the production speed of the absorbent article, and the like. Considering the adhesiveness and the production speed of the absorbent article, usually 0.5 second to 3 seconds.
Minutes, preferably 1 second to 1 minute.

In the present invention, when the absorbent layer is treated with the surfactant (d), the absorbent layer may be uniformly adhered. For example, a diluted solution having a concentration of about 1 to 10% by weight is usually prepared. Process layers. By treating with (d) after forming the absorber layer, the surfactant (d) is uniformly treated with (a), (b) and (c), so that excellent liquid permeability is obtained. And diffusivity can be obtained. Use of the synthetic fiber (a) which has been treated in advance with the surfactant (d) does not provide a sufficient effect. This process
It may be either before the heat treatment of the absorber layer or after the heat treatment. When the treatment is performed after the heat treatment, drying is usually performed after the treatment. If the absorber layer is treated before the heat treatment, the drying step is unnecessary.

There is no particular limitation on the method and apparatus for treating the absorber layer in (d). For example,
A method of dipping the absorber layer in the solution of (d) and squeezing it with a mangle or the like as necessary, a method of spraying the solution of (d) on the absorber layer, and a method of applying an oiling roll to which the solution of (d) is adhered A method of treating the absorber layer is exemplified.

Other compounds, for example, an alkyl phosphate type anionic surfactant as an antistatic agent, a quaternary ammonium salt type or an alkyl imidazolinium salt type cationic surfactant within a range not impairing the effects of the present invention,
Emulsifiers, leveling agents, other nonionic surfactants as sizing agents, other modified silicone-based surfactants, antibacterial agents, fragrances, deodorants, etc. are used as the surfactant (d) used in the present invention. It can be processed by being appropriately contained in a solution.

The absorbent layer treated with the surfactant (d) as described above may be a single layer or a plurality of layers, and if necessary, a layer of water-absorbing paper or cotton-like pulp may be superposed on the absorbent layer. An absorbent article such as a disposable diaper is provided by disposing a permeable top sheet or non-woven fabric, arranging a liquid-impermeable back sheet on the back side, and further including a gather or a tape for attachment to a human body. The material and type of the liquid-permeable top sheet, the liquid-impermeable back sheet, the gathers and the mounting tape, and the method of manufacturing the absorbent article are not particularly limited, and the known absorbent articles used in conventional absorbent articles are used. Can be used.

The liquid-permeable surface sheet used in the present invention varies depending on the final product to be used. For example, a nonwoven fabric such as polypropylene, polyethylene, polyester, rayon or the like having a good touch is used. Can be As a method for producing the nonwoven fabric, a known production method can be employed, and preferred examples include a dry method, a spun bond method, a melt blown method, and a spunlace method. Further, as the non-woven fabric, for example, a non-woven fabric of 6 d or less is preferably used, and the basis weight is preferably ²⁰ to 90 g / m ² on a basis weight. It is also possible to use a two-layer structure of different materials or a two-layer structure of mixed materials. Also,
The liquid-impermeable backing sheet used in the present invention, which varies depending on the final product intended, is made of polyethylene, polypropylene, polytetrafluoroethylene, polyester, rayon, etc., stretched, etc., and subjected to a fine pore opening treatment to allow air permeability. An impermeable film having a water-repellent treatment is used. It is preferable that the breathable film has a thickness of 20 to 60 μm. In addition, in order to satisfy the touch, ventilation, and waterproofness, it is preferable that the nonwoven fabric and the film are laminated to form a two-layer structure. More preferably, a water-impermeable film is laminated on the absorber side to form a three-layer structure. Are more preferred.

[0024]

The usefulness of the present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, disposable paper diapers will be specifically described by way of example, but the same applies to absorbent articles such as sanitary napkins and incontinent pads, and the present invention is limited to disposable paper diapers. It is not something to be done. The absorption rate, diffusion area, surface dryness, and shape retention of the disposable diaper were evaluated by the following methods. Hereinafter, unless otherwise specified,% indicates% by weight.

Absorption speed: An acrylic plate (0.5 kg in weight) having the same size as the area of a disposable diaper, centered on a cylinder (inner diameter: 3 cm), is placed on the disposable diaper, and a load of 4.5 kg is placed on the acrylic plate. (Total load: 5K
g). The acrylic plate has a hole at the center thereof for discharging the liquid in the cylinder onto the paper diaper. 80ml of artificial urine in cylinder (colored with blue ink)
Pour into absorbent diaper. 80 ml after 30 minutes
Inject the second artificial urine. Similarly, after 30 minutes, 8
0 ml of the third artificial urine was injected, and the absorption time at this time was measured to determine the absorption rate. Diffusion area: After the third injection of artificial urine and measurement of the absorption rate, the area of artificial urine absorbed and spread (colored in blue) was measured and defined as the diffusion area. Surface dryness: After measuring the diffusion area, the dryness of the surface of the disposable diaper (the place where artificial urine was injected) was judged by 10 panelists' finger touch and evaluated in the following four steps. This average was defined as surface dryness. ：: Good dry feeling ○: Slightly wet, but satisfactory level of dry feeling △: Poor dry feeling, moist state ×: No dry feeling, wet state Retention of form: 30 times after injecting artificial urine for the third time After a minute, twist the disposable diaper by hand to visually determine the shape retention after 5 minutes,
Evaluation was made in the following three stages. ◎: Restored to original shape ○: Almost restored to original shape, satisfactory level ×: Degraded shape

Absorbent layer (A) Sheath-core type composite fiber having polypropylene as a core component and polyethylene as a sheath component (“ES Fiber EA” manufactured by Chisso Corporation)
C "; 30 parts by weight of low melting point component 110 ° C.), 70 parts by weight of fluff pulp, and crosslinked sodium polyacrylate-based water-absorbing resin (absorbing amount at normal pressure 50 g / g, absorbing amount under pressure 28)
g / g, a gel elastic modulus of 92,000 dynes / cm ² , and an average particle size of 480 μm) and a mixture obtained by mixing with 50 parts by an air-flow type mixing device, and uniformly laminated so as to have a basis weight of about 400 g / m ^2. / Cm ^{2 at} a pressure of 90 seconds. Next, the absorber layer was cut into a rectangle of 14 cm × 36 cm,
Polyoxyethylene-modified dimethylpolysiloxane (“San Silicon M-84” manufactured by Sanyo Chemical Industries, Ltd .; average molecular weight: about 1,000, polyoxyethylene group content: about 50)
%) Of a 1% aqueous solution, and then treated with hot air at 130 ° C. for 3 minutes to obtain an absorber layer (A) of the present invention.

Absorbent layer (B) and (C) Absorbent layer (A) except that the ratio (weight ratio) of the conjugate fiber, fluff pulp and water absorbent resin in the absorbent layer (A) is changed as follows. 2) Absorber layer (B)
And an absorber layer (C). Absorbent layer (B): composite fiber / fluff pulp / water absorbent resin = 50/50/70 Absorbent layer (C): composite fiber / fluff pulp / water absorbent resin = 100/0/100

Absorber layer (D) In the absorber layer (A), instead of 10 parts by weight of a 1% aqueous solution of polyoxyethylene-modified dimethylpolysiloxane,
Except for spraying 25 parts by weight, an absorber layer (D) was obtained in the same manner as the absorber layer (A).

Absorber layers (E) and (F) In the absorber layers (A) and (D), a random copolymer of polyoxyethylene / polyoxypropylene (copolymer) was used in place of the polyoxyethylene-modified dimethylpolysiloxane. Polymerization molar ratio: oxyethylene / oxypropylene =
75/25) Modified dimesyl polysiloxane (average molecular weight about 2,500, polyoxyethylene group content about 40%)
Was used in the same manner as in the absorber layer (A) or (D), except that was used to obtain an absorber layer (E) and an absorber layer (F).

Absorbent layer (G) In the absorbent layer (A), a sheath-core type composite fiber ("ES fiber EAC" manufactured by Chisso Corporation; low melting point component melting point 110)
C), instead of using the same amount of eccentric sheath-core composite fiber ("ES fiber EA" manufactured by Chisso Corp .; melting point 110 ° C, low melting point component) having polypropylene as a core component and polyethylene as a sheath component. An absorber layer (G) was obtained in the same manner as the body layer (A).

Absorbent layer (H) In the absorbent layer (A), the crosslinked sodium polyacrylate-based water-absorbing resin (normal pressure absorption: 50 g / g, pressure absorption: 2 g)
8 g / g, gel elastic modulus 92,000 dynes / cm ² , average particle size 480 μm) instead of surface-crosslinked starch-sodium acrylate copolymer-based water-absorbent resin particles (normal pressure absorption 58 g / g, Pressure absorption 36 g / g, gel elasticity 105,000 dynes / cm ² , average particle size 350 μm)
Was used in the same manner as in the absorber layer (A) except that the same amount was used to obtain an absorber layer (H).

Comparative absorber layer (f) Comparative absorber layer (A) was prepared in the same manner as absorber layer (A) except that polyoxyethylene-modified dimethylpolysiloxane was not sprayed on the absorber layer. (F) was obtained.

Comparative absorbent layer (g) In the comparative absorbent layer (f), the weight ratio of composite fiber / fluff pulp / water-absorbent resin was changed to 30/70/50 instead of composite fiber / fluff pulp / water absorption. Resin ratio = 1
A comparative absorber layer (g) was obtained in the same manner as the comparative absorber layer (f) except that the ratio was set to 00/0/100.

Comparative Absorbent Layers (h) to (j) In the absorbent layer (f) of the present invention, the composite fiber / fluff pulp / water-absorbent resin was replaced by a composite weight ratio of 30/70/50. Comparative absorber layers (h) to (j) were obtained in the same manner as the absorber layer (A) except that the weight ratio of fiber / fluff pulp / water-absorbent resin was changed as described below. Comparative absorbent layer (h): composite fiber / fluff pulp / water absorbent resin = 0/100/50 Comparative absorbent layer (i): composite fiber / fluff pulp / water absorbent resin = 10/90/50 comparative Absorber layer (j): composite fiber / fluff pulp / water-absorbent resin = 50/50/350

Comparative Absorbent Layer (k) In the absorbent layer (A) of the present invention, the polyoxyethylene-modified dimethylpolysiloxane was replaced with a polyoxyethylene-modified dimesylpolysiloxane (average molecular weight of about 1,0
A comparative absorber layer (k) was obtained in the same manner as the absorber layer (A) except that the polyoxyethylene group content was about 20%.

Examples 1 to 8 Each of the absorber layers (A) to (H) of the present invention was 14 cm × 36 cm.
Cut into rectangles, and water-absorbing paper of the same size as the absorber layer is placed on each of the upper and lower sides, and furthermore, a stretched microporous 40-μm-thick breathable non-permeable polypropylene used in ordinary paper diapers. A model paper diaper was prepared by disposing a polyester nonwoven fabric having a basis weight of 60 g / m ² produced by a dry method on the front side with the film on the back side. The absorption rate, diffusion area, surface dryness,
Table 1 shows the results of evaluating the shape retention.

Comparative Examples 1 to 6 Comparative model paper diapers were prepared in the same manner as in the examples, using comparative absorber layers (f) to (k). Table 1 shows the results of evaluating the absorption rate, diffusion area, surface dryness, and shape retention of these model diapers.

[0038]

[Table 1]

Absorber layer (I) Sheath-core type composite fiber having polypropylene as a core component and polyethylene as a sheath component (“ES Fiber EA” manufactured by Chisso Corporation)
C "; 30 parts by weight of low melting point component 110 ° C.), 70 parts by weight of fluff pulp, and crosslinked sodium polyacrylate-based water-absorbing resin (absorbing amount at normal pressure 50 g / g, absorbing amount under pressure 28)
g / g, a gel elastic modulus of 92,000 dynes / cm ² , an average particle size of 480 μm) and 50 parts by weight of a mixture obtained by mixing with an air-flow type mixing device, and uniformly laminated so as to have a basis weight of about 400 g / m ² . Pressing was performed at a pressure of 5 kg / cm ² for 90 seconds.
Next, the absorber layer was cut into a rectangle of 14 cm × 36 cm, and a 1% aqueous solution of polyoxyethylene oleyl cetyl ether (“Emulmin 60”; HLB 10.3, manufactured by Sanyo Chemical Industries, Ltd.) as a nonionic surfactant was used. Was sprayed at 10 ° C., and treated with hot air at 130 ° C. for 3 minutes to obtain an absorber layer (A) of the present invention.

Absorber layer (J) and (K) Absorber layer (I) Same as absorber layer (I) except that the weight ratio of conjugate fiber, fluff pulp and water absorbent resin is changed as follows. Thus, an absorber layer (J) and an absorber layer (K) were obtained. Absorber layer (J): composite fiber / fluff pulp / water-absorbent resin = 50/50/70 Absorber layer (K): composite fiber / fluff pulp / water-absorbent resin = 100/0/100

Absorber layer (L) In the absorber layer (I), instead of 10 parts by weight of a 1% aqueous solution of polyoxyethylene oleyl cetyl ether, 2 parts
Except for spraying 5 parts by weight, an absorber layer (L) was obtained in the same manner as the absorber layer (I).

Absorber layer (M) to (P) Absorber layer (I) is the same as absorber layer (I) except that the following surfactant is used in place of polyoxyethylene oleyl cetyl ether. And the absorber layer (M) ~
(P) was obtained. Absorbent layer (M): polyoxyethylene oleyl cetyl ether (Nonionic surfactant "Emulmin 40" manufactured by Sanyo Chemical Industries, Ltd .; HLB 8.0) Absorbent layer (N): polyoxyethylene nonyl phenyl ether (Non-pol 40, a nonionic surfactant manufactured by Sanyo Chemical Industries, Ltd .; HLB 8.9) Absorber layer (O):
Sorbitan monolaurate.EO4mol (HLB8.
6) Absorber layer (P): polyoxyethylene lauryl myristyl ether (nonionic surfactant "Nonipol Soft SS-50" manufactured by Sanyo Chemical Industries, Ltd .; HLB10.
6)

Absorbent layer (Q) In the absorbent layer (I), a sheath-core type composite fiber (“ES fiber EAC” manufactured by Chisso Corp .; low melting point component melting point 110)
C), instead of using the same amount of eccentric sheath-core composite fiber ("ES fiber EA" manufactured by Chisso Corp .; melting point 110 ° C, low melting point component) having polypropylene as a core component and polyethylene as a sheath component. An absorber layer (Q) was obtained in the same manner as in the body layer (I).

Absorbent layer (R) In the absorbent layer (I), a crosslinked sodium polyacrylate-based water-absorbing resin (normal pressure absorption 50 g / g, pressure absorption 2
8 g / g, gel elastic modulus 92,000 dynes / cm ² , average particle size 480 μm) instead of surface-crosslinked starch-sodium acrylate copolymer-based water-absorbent resin particles (normal pressure absorption 58 g / g, Pressure absorption 36 g / g, gel elasticity 105,000 dynes / cm ² , average particle size 350 μm)
Was used in the same manner as in the absorber layer (I) except that the same amount was used to obtain an absorber layer (R).

Comparative absorber layer (m) In the absorber layer (I), except that polyoxyethylene oleyl cetyl ether was not sprayed on the absorber layer,
A comparative absorber layer (m) was obtained in the same manner as in the absorber layer (I).

Comparative Absorbent Layer (n) In the comparative absorbent layer (I), the weight ratio of the composite fiber / fluff pulp / water-absorbent resin was changed to 30/70/50 instead of the composite fiber / fluff pulp / water absorption. A comparative absorber layer (n) was obtained in the same manner as the comparative absorber layer (m) except that the weight ratio of the conductive resin was set to 100/0/100.

Comparative Absorbent Layers (o) to (q) In the absorbent layer (I) of the present invention, the composite fiber was replaced with the composite fiber / fluff pulp / water-absorbent resin weight ratio = 30/70/50. Comparative absorber layers (o) to (q) were obtained in the same manner as the absorber layer (I), except that the weight ratio of / fluff pulp / water-absorbent resin was changed as follows. Comparative absorbent layer (o): composite fiber / fluff pulp / water absorbent resin = 0/100/50 Comparative absorbent layer (p): composite fiber / fluff pulp / water absorbent resin = 10/90/50 comparative Absorber layer (q): composite fiber / fluff pulp / water-absorbent resin = 50/50/350

Comparative Absorber Layers (r) and (s) In the absorber layer (I) of the present invention, instead of the polyoxyethylene oleyl cetyl ether of HLB 10.3,
Comparative absorber layers (r) and (s) were obtained in the same manner as in the absorber layer (I) except that a surfactant having the following HLB was used. Comparative absorber layer (r): polyoxyethylene nonylphenyl ether (nonionic surfactant "Nonipol 20" manufactured by Sanyo Chemical Industries, Ltd .; HLB 5.7) Comparative absorber layer (s): polyoxyethylene Nonyl phenyl ether (Nonpol 120, a nonionic surfactant manufactured by Sanyo Chemical Industries, Ltd .; HLB 14.8)

Examples 9 to 18 Absorbent layers (I) to (R) of the present invention were each 14 cm × 36 cm.
Cut into rectangles, and water-absorbing paper of the same size as the absorber layer is placed on each of the upper and lower sides, and furthermore, stretched micropores used in ordinary disposable diapers, with a thickness of 40 μm and a breathable non-permeable polypropylene having a thickness of 40 μm A model paper diaper was prepared by disposing a polyester nonwoven fabric having a basis weight of 60 g / m ² produced by a dry method on the front side with the film on the back side. The absorption rate, diffusion area, surface dryness,
Table 2 shows the results of evaluating the shape retention.

Comparative Examples 7 to 13 Comparative model paper diapers were prepared in the same manner as in the Examples, using the comparative absorber layers (m) to (s). Table 2 shows the results of evaluating the absorption rate, diffusion area, surface dryness, and shape retention of these model diapers.

[0051]

[Table 2]

[0052]

The absorbent article of the present invention has the following features and effects. It shows excellent absorption performance and absorption speed even for repeated absorption. It has good liquid diffusibility and excellent dry feeling on the surface after absorption. Moisture of the liquid to be absorbed is reduced. It shows excellent shape retention even with external forces such as shearing, compression, and kinking caused by movement of the wearer in a wet state. Excellent in integration between the water-absorbent resin and the fiber base material.

Because of the above effects, the absorbent article of the present invention is suitable for disposable disposable diapers (disposable diapers for children and adults). It is especially suitable for thin disposable paper diapers having a large ratio of water absorbent resin / fiber base material. Other sanitary materials (sanitary napkins, incontinent pads, breast milk pads, surgical underpads, puerperium mats,
Suitable for dressing materials for wound protection, pet sheets, etc.) and various absorbent sheets (freshness preserving sheets, drip absorbing sheets, dew condensation preventing sheets, rice seedling raising sheets, concrete curing sheets, oil / water separation sheets, fire extinguishing sheets, etc.) Can be used for

Continuation of front page (56) References JP-A-55-142701 (JP, A) JP-A-60-18173 (JP, A) JP-A-56-91052 (JP, A) JP-A-58-32641 (JP) JP-A-63-303184 (JP, A) JP-A-52-101196 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61F 13/15

Claims (6)

(57) [Claims] 1. An absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet and an absorber layer provided between the two sheets, wherein the absorbent layer does not swell in water. (A) an absorbent layer composed of the water-absorbent resin (c) or an absorbent layer composed of the synthetic fiber (a), the cellulosic fiber (b), and the water-absorbent resin (c); ) And (b) on a weight basis (100 to 2).
0): (0 to 80), the amount of (c) is 25 to 75% by weight based on the total weight of (a), (b) and (c), and the absorbent layer is made of poly 25 content of oxyethylene groups
Polyoxyalkylene-modified silicone-based surfactant (d1) and / or HLB of 8 to 1% by weight
An absorbent article treated with a surfactant (d) selected from the non-silicone surfactants (d2). 2. The absorbent article according to claim 1, wherein the synthetic fiber (a) is at least one selected from the group consisting of polyolefin fibers, polyester fibers, and composite fibers thereof. 3. The absorption according to claim 1, wherein the water-absorbent resin (c) is a particulate hydrophilic cross-linked polymer containing acrylate and / or acrylic acid as a main monomer component of the polymer. Products. 4. The water-absorbent resin (c) has a normal pressure absorption amount to physiological saline of 45 to 75 g / g and a pressure absorption amount of 25 to 25 g / g.
50 g / g and a gel elasticity of 30,000-200,
The absorbent article according to any one of claims 1 to 3, wherein the absorption rate is 000 dynes / cm ² . 5. The treatment amount of the surfactant (d) is (a)
The absorbent article according to any one of claims 1 to 4, wherein the content is 0.01 to 5% by weight based on the total weight of (b) and (c). 6. The surfactant (d) having a molecular weight of 500 to 1
000, the content of polyoxyethylene groups is 40 to 6
The absorbent article according to any one of claims 1 to 5, which is 0% by weight of a polyoxyethylene-modified dimethylpolysiloxane and / or a nonionic surfactant having an HLB of 9 to 13.