JP4455835B2 - Water-absorbing composite sheet and method for producing the same - Google Patents

Description

【００６６】
Ｂ．失禁ライナー評価方法
（評価用失禁ライナー作成方法）
４．５ｃｍ×１４ｃｍに切り出した実施品１、２及び比較品を不織布とポリエチレンシートで挟み、周囲をホッチキスで固定し紙おむつ評価サンプルとした。
【００６７】
図１に、作製した失禁ライナーの構成を示した。図１中（ａ）は実施品１を用いて作製した失禁ライナー、（ｂ）は実施品２を用いて作製した失禁ライナー、（ｃ）は比較品を用いて作製した失禁ライナーである。図１中、２は不織布、４は吸水性シート、６はトイレットペーパー、８は不織布、１０はポリエチレンシートである。
【００６８】
（失禁ライナー評価方法）
失禁ライナーを水平面上に置き、中心部分に測定用の筒（φ２６ｍｍ）を乗せ、その中に人工尿（青色に着色したもの）５ｍｌを一気に流し込んだ。筒内の人工尿が失禁ライナー中に吸収されるのに要する時間を測定し、これを第一吸水時間とした。３分間放置後、再び失禁ライナー中心部分に測定用の筒を置き、人工尿５ｍｌを一気に流し込み、同様にして第二吸水時間を測定した。２分間放置後、失禁ライナー中心部分に予め質量を測定してある４ｃｍ×５ｃｍに切り出したキッチンペーパー１０枚（Ｗ１ｇ）を乗せた。その後、キッチンペーパーの上に更に１００ｇ（４ｃｍ×５ｃｍ）の錘を乗せて１０秒間加圧した。キッチンペーパーを取り除き、その質量を測定した（Ｗ２ｇ）。以下の式で逆戻り量を求めた。
【００６９】
逆戻り量＝Ｗ２−Ｗ１
逆戻り量を測定した後、失禁ライナーを切り開き、人工尿の拡散性を定規で測定し拡散距離を求めた。
【００７０】
【表２】

【００７１】
【発明の効果】
本発明においては、繊維質基材に微細な吸水性樹脂粒子が多数固着した吸水性シートと、繊維質基材シートとを張合わせて一体化して複合シート化したので、該吸水性樹脂粒子が有する潜在的吸水能力を効率よく引出し、多量の水分を急速に吸収できる。更に本吸水性複合シートの表面に熱圧縮による凹凸模様を形成する場合は、柔軟性を損うことなく、より高い吸水能力を発揮することができる。
【図面の簡単な説明】
【図１】失禁用ライナーの構成を示す概略図で、（ａ）は、実施例１の吸水性複合シートを用いた場合、（ｂ）は実施例２の吸水性複合シートを用いた場合、（ｃ）は比較例１の吸水シートを用いる場合を示す。
【符号の説明】
２ 不織布
４ 吸水性シート
６ トイレットペーパー
８ 不織布
１０ ポリエチレンシート[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water-absorbing composite sheet formed by adhering a water-absorbing sheet and a fibrous sheet. The water-absorbent composite sheet has a high water absorption rate and a high water absorption amount while maintaining the flexibility of the fibrous base material, and is useful for producing disposable diapers, sanitary napkins and the like.
[0002]
[Prior art]
Conventionally, water-absorbent sheets used for paper diapers, sanitary napkins, etc. are uniformly dispersed by adhering crosslinked water-absorbent resin particles such as polyacrylic acid to a fibrous base sheet such as paper, pulp, and nonwoven fabric. There is something. However, in this water absorbent sheet, few water absorbent resin particles are securely fixed to the fibrous base sheet, and the water absorbent resin particles easily fall off. In addition, the operation is complicated in terms of handling powder particles.
[0003]
In order to solve the above problems, after spraying a monomer mixture aqueous solution composed of acrylic acid and acrylate onto a fibrous base material, the sprayed single amount is irradiated with ionizing radiation, fine particle ionizing radiation, etc. A water-absorbent sheet in which a body mixture is polymerized to fix a water-absorbent resin to a fibrous base material sheet is known.
[0004]
Patent Document 1 discloses a method for producing a water-absorbent sheet similar to that described above by polymerizing a monomer aqueous solution supported on a fibrous base material by UV irradiation. In the same publication, after polymerization, most of the monomer is polymerized by UV irradiation so that no unreacted monomer remains, and then the electron beam is irradiated, and then UV is irradiated, followed by polymerization conversion. It is stated that it is preferable to increase the rate. As described above, even when the UV polymerization method is employed, in order to produce a water-absorbent sheet in which unreacted monomers do not remain, it is currently necessary to employ a complicated production process.
[0005]
In Patent Document 2, a water-absorbing and water-holding ability is high by dropping and adhering a monomer aqueous solution droplet during polymerization onto a fibrous base material to complete redox polymerization on the fibrous base material. A method of manufacturing a sheet is described.
[0006]
Patent Document 3 discloses that a similar water-absorbent sheet has a porosity of 50 to 99.5% as the fibrous base material, and the primary particle diameter of the water-absorbent resin particles carried on the base material. Is 50 to 1000 μm, and the amount of water-absorbing resin supported per 1 m ^{2 of the} substrate is preferably 10 to 500 g.
[0007]
According to the inventions described in Patent Documents 1 to 3, since the monomer aqueous solution is polymerized on the fibrous base material, the water-absorbing resin particles obtained are fixed to and integrated with the fiber. Many of the problems that occur when applying a functional resin to a fibrous base material have been solved.
[0008]
However, the water-absorbing sheet described in each of the above publications has an insufficient water-absorbing rate, and a water-absorbing sheet with a higher water-absorbing rate is particularly required for use in sanitary goods such as diapers.
[0009]
In order to solve these problems, a method has been proposed in which a fiber web having a difference in fiber density alternately along the surface direction is used as a fibrous base material (Patent Document 4).
[0010]
According to this invention, although the water-absorbing polymer polymerized on the fiber web is stably fixed to the fibrous base material, when a monomer is applied on such a fiber web, Monomer droplets coalesce before polymerization or penetrate into the fiber. As a result, the water-absorbent sheet obtained by polymerizing this monomer is not uniform and tends to lack flexibility. Therefore, according to each of the above-described inventions, a high-performance water-absorbent sheet having a balanced performance required as a water-absorbent sheet has not been obtained conventionally.
[0011]
[Patent Document 1]
JP-A-1-292103 (pages 1 to 3)
[Patent Document 2]
JP 2000-328456 A (Claim 1)
[Patent Document 3]
JP-A-9-67403 (Claims)
[Patent Document 4]
Japanese Patent No. 2554136 (Claim 1)
[0012]
[Problems to be solved by the invention]
In the present invention, a water-absorbing composite sheet having a high water absorption rate, a large amount of water absorption per water-absorbing resin and containing only a few unreacted monomers, and a method for producing the same are provided. Let it be an issue.
[0013]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the inventors of the present invention bonded and integrated a water-absorbent sheet having a large number of fine water-absorbent resin particles fixed to a fibrous base material and the fibrous base material sheet. When the composite sheet is formed, the composite sheet can efficiently draw out the potential water absorption capability of the water-absorbent resin particles, and can absorb a large amount of water rapidly. It has been found that by forming the film, a higher water absorption capacity can be exhibited without impairing flexibility. The present invention has been completed based on the above discovery.
[0014]
That is, the present invention for solving the above problems comprises a water absorbent sheet formed by adhering water absorbent resin particles to a fibrous base material, and a fibrous base material sheet adhered to at least one surface of the water absorbent sheet. Is a water-absorbent composite sheet characterized by In the present invention, the water-absorbent composite sheet is characterized in that the water-absorbent sheet and the fibrous base sheet are adhered by heat compression using a pair of rolls in which at least one roll is heated. In this manufacturing method, it is included that the surface of at least one roll is provided with an uneven pattern.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
(Water-absorbing composite sheet)
The water-absorbent composite sheet of the present invention comprises a water-absorbent sheet and a fibrous base sheet adhered to one or both sides of the water-absorbent sheet. Adhesion between the water-absorbent sheet and the fibrous base material sheet can employ any adhering method such as use of an adhesive, a binder, and fusion.
[0016]
It is preferable that an uneven pattern is formed on the surface of the water-absorbent composite sheet. The depth of the uneven pattern is preferably 0.01 to 1 mm. Further, the concavo-convex pattern is a continuous pattern of polygons, circles, ellipses, etc. that fit in a circle with a pitch of 10 mm or less, preferably 0.05 to 5 mm, or a diameter of 10 mm or less, preferably 1 to 5 mm. What was formed in is preferable.
[0017]
(Water absorbent sheet)
The water-absorbent sheet is formed by adhering water-absorbent resin particles in a rosary shape to fibers of a fibrous base material. The water-absorbing resin particles are mainly composed of hydrophilic monomers such as acrylic acid and salts thereof, and these are polymerized. A typical example is a water-absorbing sheet produced by the method described later. The water absorbent resin particle diameter is preferably 30 to 300 μm. Fixed amount for the fibrous base material of the water-absorbent resin in 100 g / m ² or more, preferably 150~1000g / m ^2.
[0018]
(Fiber base sheet)
In the present invention, the fibrous base material sheet (hereinafter sometimes referred to as an adhesive sheet) to be adhered to the water absorbent sheet includes a fibrous pad, a carded web, a woven fabric such as cotton gauze, and a knitted fabric. And non-woven fabrics.
[0019]
As the fiber base sheet, it is preferable that the fiber base sheet itself is excellent in water absorption. Therefore, as the fiber constituting the fiber base sheet, hydrophilic fibers such as wood pulp, rayon, cotton, regenerated cellulose, etc. Synthetic fibers that have been subjected to chemical treatment are preferred.
[0020]
Specifically, a non-woven fabric made of a synthetic fiber subjected to a hydrophilic treatment, or a paper material such as toilet paper, paper towel, napkin paper, dust paper, and wadding (these are generally collectively referred to as sanitary paper). A paper material such as sanitary paper is particularly preferable.
[0021]
Examples of the synthetic fiber include polyester, polyethylene, polypropylene, polyamide, polyvinyl alcohol, polyacrylonitrile, and polyvinyl chloride, and polyester, polyamide, polypropylene, and polyethylene are preferable.
[0022]
Among the nonwoven fabrics used for the production of the water-absorbent sheet described later, all nonwoven fabrics formed from hydrophilic fibers or synthetic fibers subjected to hydrophilic treatment can be used as an adhesive sheet.
[0023]
(Method for producing water-absorbing composite sheet)
Hereinafter, an example of a method for producing a water-absorbing composite sheet will be described.
[0024]
First, the manufacturing method of a water absorbing sheet is demonstrated. As shown below, the water-absorbent sheet is a fibrous base material that has not been subjected to the raising treatment, or a monomer aqueous solution mainly composed of acrylic acid and / or a salt thereof on the fibrous base material that has undergone the raising treatment. After being supported in the form of fine particles, it is produced by polymerizing the monomer supported on the fibrous base material.
[0025]
As the fibrous base material, a nonwoven fabric is preferable. In the present invention, the non-woven fabric includes a non-woven fabric in a narrow sense, that is, a carded or air-laid web and a loosely convergent pad of fibers, in addition to a fiber web to which base fibers are fixed with a binder.
[0026]
The nonwoven fabric used in the present invention is preferably produced by heat-sealing base fibers with binder fibers. This non-woven fabric is more preferable because it can be raised later.
[0027]
The non-woven fabric produced by heat-sealing uniformly mixes base fibers and heat-sealable binder fibers in a ratio of, for example, base fibers / binder fibers = 40 to 90/60 to 10 (mass ratio), It can be easily manufactured by forming a web using means such as ding and then heat-sealing with each other.
[0028]
As basis weight of the nonwoven fabric is suitably 10 to 100 g / m ^2. The bulkiness of the nonwoven fabric is preferably 0.1 × 10 ^{2 to} 2.0 × 10 ² ml / g in volume per gram of nonwoven fabric, that is, specific volume.
[0029]
The nonwoven fabric is preferably manufactured using base fibers having a fineness of 1.0 to 20 dtex and a fiber length of 25 to 128 mm. When the fineness of the base fiber is less than 1.0 dtex, the air permeability of the obtained nonwoven fabric is likely to be insufficient. On the other hand, if it exceeds 20 dtex, it is difficult to increase the amount of water-absorbing resin attached.
[0030]
When the fiber length of the base fiber is less than 25 mm, the strength of the nonwoven fabric tends to decrease. Moreover, when performing the raising process by the heating mentioned later, the raising of a fiber is insufficient and the fixed amount of a water absorbing resin tends to become too small. On the other hand, if it exceeds 128 mm, the carding process performed at the time of nonwoven fabric manufacture will become difficult.
[0031]
The base fiber material is a non-hydrophilic resin in that the monomer aqueous solution adheres to the fibers in independent fine particles when the monomer aqueous solution is atomized and supported on the substrate surface as described later. Is preferred. Specific examples include polyethylene, polypropylene, ethylene / propylene copolymer, polyethylene terephthalate, polyamide, polystyrene, polyacrylonitrile, polyvinyl chloride, and polyvinylidene chloride. Moreover, the nonwoven fabric which contains hydrophilic fibers, such as rayon, cotton, and a regenerated cellulose fiber, as a small component is also preferable. A non-woven fabric produced using such a non-hydrophilic resin fiber as a base fiber is preferable in that a water-absorbing resin obtained by polymerizing an aqueous monomer solution can be fixed to the fiber in fine particles, but to some extent on the non-woven fabric itself. Without the hydrophilic property, a paper diaper, a sanitary product and the like manufactured using the water-absorbing composite sheet are liable to leak when used. Therefore, the non-woven fabric is a non-woven fabric such as polyoxyethylene alkyl ether, polyoxyethylene phenol ether, polyoxyethylene sorbitan ester, polyoxyethylene alkyl fatty acid ester, polyoxyethylene oxypropylene block polymer, etc. subjected to hydrophilic treatment. Non-woven fabrics coated with an anionic surfactant such as a reactive surfactant, higher fatty acid salt, alkylnaphthalene sulfonate, dialkyl succinate or alkyl sulfate ester salt are preferred.
[0032]
As a specific hydrophilization treatment method, when spinning the base fiber, the above-mentioned surfactant, that is, the hydrophilizing agent may be mixed in advance with the spinning raw material resin, and then it may be spun. Further, a hydrophilizing agent dissolved in a solvent or the like may be sprayed on the fiber after spinning.
[0033]
The non-woven fabric may be used as it is, but is preferably raised by heating. The heating temperature is preferably near the softening point of the base fiber of the nonwoven fabric, and a temperature in the range of 70 to 150 ° C. is practically selected. The heating time varies depending on the heating temperature, but usually several to 180 seconds is appropriate. Further preferable heating conditions are heating at 80 to 110 ° C. for 20 to 60 seconds. The heating means is not limited. For example, the nonwoven fabric may be passed through a heating furnace over a predetermined time, hot air may be blown onto the fibrous base material, or the nonwoven fabric may be heated by an infrared lamp or the like. .
[0034]
An aqueous solution of a monomer mainly composed of acrylic acid and / or a salt thereof (hereinafter collectively referred to as an acrylic acid monomer) is sprayed and supported on a fibrous base material such as the above-mentioned nonwoven fabric. A preferred monomer is a mixture of acrylic acid and acrylate in which 20 to 90 mole percent of acrylic acid has been converted to an alkali metal salt or ammonium salt.
[0035]
Monomers other than acrylic acid monomers can be used in combination. Specific examples include methacrylic acid or a salt thereof, (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, and 2-acrylamido-2-methyl. Examples thereof include propanesulfonic acid or a salt thereof. The preferable usage amount of such a monomer is 20 mol% or less based on the total amount with the acrylic acid monomer.
[0036]
The preferable concentration of the monomer in the monomer aqueous solution is 20 to 80% by mass, and more preferably 40 to 60% by mass.
[0037]
In addition to the monomer, it is preferable to add a crosslinking agent, a polymerization initiator, and the like to the monomer aqueous solution.
[0038]
Cross-linking agents include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and glycerin tri (meth) acrylate. N, N′-methylenebisacrylamide, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl phosphate and the like.
[0039]
The addition ratio of the crosslinking agent is preferably from 100 to 1000 ppm, particularly preferably from 300 to 750 ppm, based on the total mass of the monomers.
[0040]
The polymerization of the monomer can be performed by a general radical polymerization method. As a polymerization initiation method, a thermal polymerization method using a compound that generates radicals by heat as a polymerization initiator, or a method of initiating polymerization by irradiation with an active energy ray such as an ultraviolet ray or an electron beam can be employed. A thermal polymerization method or a method of irradiating ultraviolet rays in the presence of a photopolymerization initiator (hereinafter referred to as a UV irradiation polymerization method) is preferable, and a UV irradiation polymerization method is particularly preferable.
[0041]
Examples of the thermal polymerization initiator include water-soluble radical polymerization initiators such as hydrogen peroxide, ammonium persulfate, potassium persulfate, t-butyl hydroperoxide, and cumene hydroperoxide. These compounds may be used as a redox polymerization initiator in combination with a reducing compound such as sodium bisulfite, sodium thiosulfate, L-ascorbic acid or amine.
[0042]
The photopolymerization initiator used for polymerization by the UV irradiation polymerization method is not particularly limited, and any photopolymerization initiator that can generate radicals by ultraviolet rays can be used. An initiator can be appropriately selected according to the purpose and used. Specifically, azo compounds such as 2,2′-azobis (2-aminodipropane) salt, ketones such as 1-benzoyl-1-hydroxycyclohexane and benzophenone, benzoin and alkyl ethers thereof, benzyl ketals, and anthraquinone Examples thereof include derivatives.
[0043]
The monomer aqueous solution can be carried in the form of an independent fine particle on the fibrous base material by spraying (coating) it onto the fibrous base material in the form of a mist as described above. As a method for atomizing the monomer aqueous solution, a known atomization technique can be used. For example, examples of the droplet formation method include a droplet formation method using a spray nozzle, a droplet formation method using a rotating disk atomizer, and an ultrasonic method.
[0044]
The average diameter of the spray droplets is preferably 50 to 500 μm. When the average diameter is less than 50 μm, the droplet sprayed on the fibrous base material is likely to penetrate to the back side without adhering to the fibrous base material, and thus it may be difficult to adhere to the fibrous base material. When the average diameter of the droplets exceeds 500 μm, the adhesion of the droplets becomes uneven, and as a result, the water absorption amount and the water absorption rate of the water absorbent sheet obtained by polymerization may be insufficient. The monomer aqueous solution having a size of 50 to 500 μm is subjected to polymerization and drying steps to become water-absorbing resin particles of approximately 30 to 300 μm, and is fixed to the fibrous base material.
[0045]
The carrying amount of the monomer aqueous solution is an amount such that the water-absorbent resin obtained by the polymerization is fixed to the fibrous base material in an amount of 5 to 500 g / m ² , preferably 20 to 300 g / m ² .
[0046]
After the water-absorbing sheet is produced by the above method, it is desirable that an aqueous solution of a cross-linking agent having a plurality of carboxyl groups and reactive epoxy groups (hereinafter referred to as a surface treatment agent) is sprayed on the water-absorbing sheet and heated. By this operation, the degree of crosslinking of the surface layer of the water-absorbent resin particles can be further increased.
[0047]
The water absorbent sheet obtained as described above is then stuck to the sticking sheet to obtain the water absorbent composite sheet of the present invention.
[0048]
As a sticking method, there are a method using an adhesive or the like, a method of fusing, and the like. A particularly preferable sticking method is a sticking method by heat compression.
[0049]
The thermal compression is preferably performed using a hot press, a hot roll, an embossing roll, or the like.
[0050]
The heat compression temperature is preferably 50 to 150 ° C, more preferably 70 to 120 ° C. When the heat compression temperature is less than 50 ° C., a sufficient compression effect cannot be obtained. When the temperature is higher than 150 ° C., the flexibility of the water-absorbent composite sheet obtained by thermally melting the fibrous base material or the sticking sheet may be impaired.
[0051]
The hot compression pressure is preferably from 0.01 to 100 MPa, more preferably from 0.1 to 10 MPa. Although heat compression time changes with heat compression temperature and heat compression pressure, 1 to 100 second is preferable.
[0052]
When heat-compressing on an industrial scale, it is particularly preferable to use a heat roll. Specifically, while pressurizing a pair of rolls to a linear pressure of 1 to 100 kg / cm, the laminate of the water absorbent sheet and the adhesive sheet is continuously guided between the rolls, and heat is generated between the rolls. Compress.
[0053]
The gap between the pair of rolls used for thermal compression is preferably 10 to 500 μm, although it depends on the thickness of the laminate to be thermally compressed. When the thickness is less than 10 μm, the fibrous base material or the sticking sheet may be cut. On the other hand, when it exceeds 500 μm, the compression effect is insufficient.
[0054]
In the pair of rolls, it is preferable that an uneven pattern is formed on at least one of the rolls. The depth of the concavo-convex pattern is preferably 0.001 mm or more, and more preferably 0.01 to 1 mm. The concavo-convex pattern is preferably such that the concavo-convex pattern is repeated at intervals of 10 mm or less, or a pattern that fits in a circle having a diameter of 10 mm is continuously formed at intervals of 10 mm or less. In the case of a pattern having a repetition interval exceeding 10 mm or a pattern that does not fit in a 10 mm circle, the advantages of the present invention that are generated by compressing the fibrous base material may not be sufficiently exhibited.
[0055]
By this heat compression, preferably heat compression that forms a concavo-convex pattern, the water-absorbent sheet and the adhesive sheet are bonded and integrated, and water absorption performance (water absorption speed, water absorption, liquid diffusibility, liquid reversion prevention property, etc.) Can be further improved.
[0056]
【Example】
(Comparative Example 1)
Tetraethylene glycol diacrylate (Aronix M-240, manufactured by Toagosei Co., Ltd.) 0.05 as a crosslinking agent in a monomer component aqueous solution (monomer component 42 mass%) composed of 70 mol% sodium acrylate and 30 mol% acrylic acid 0.05 Mass% (based on monomer component) was added and cooled to 20 ° C. Subsequently, nitrogen gas was blown into the monomer component aqueous solution, and the dissolved oxygen amount was adjusted to 1 ppm or less. In this monomer component aqueous solution, 0.02% by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (as a monomer component) as a photopolymerization initiator and 0.15% by mass of sodium persulfate as an oxidative polymerization initiator (as compared to Monomer component) was added and mixed to prepare an aqueous monomer solution for polymerization. After applying the above polymerizable monomer aqueous solution by spraying onto an air-through nonwoven fabric (weight per unit area: 25 g / m ² ) made of PE / PET that has been subjected to a hydrophilic treatment by spraying to 357 g / m ² , a nitrogen atmosphere Polymerization was performed by irradiating with ultraviolet rays using a high-pressure mercury lamp (ultraviolet light amount: 2,500 mj / cm). The obtained water-absorbent sheet (Comparative Product 1) was flexible, and the amount of water-absorbent resin particles fixed was 150 g / m ² .
[0057]
Example 1
Obtained in Comparative Example 1 the water-absorbent sheet air-through nonwoven fabric made of PE / PP, having undergone a hydrophilic treatment (basis weight: 35g / m ²⁾ with a heating roll (roll surface temperature of 80 ° C., nip pressure 70 kg / cm) And subjected to thermal compression. The roll was formed with an uneven pattern (depth 0.6 mm) having a diamond pattern (side length 2 mm). Thus, a water-absorbent composite sheet (Example 1) subjected to heat embossing was obtained.
[0058]
(Example 2)
Between the air-through nonwoven fabric (weight per unit area: 35 g / m ² ) made of PE / PET that has been subjected to a hydrophilic treatment, and the toilet paper (weight per unit area 20 g / m ² ) between the water absorbent sheet obtained in Comparative Example 1 The product was sandwiched and sent to a heating roll, and heat embossing similar to that in Example 1 was performed to obtain a water-absorbing composite sheet (Example Product 2).
[0059]
The following evaluation tests were performed using the above-mentioned products 1 and 2 and comparative product 1. The results are shown in Table 1.
[0060]
A. Evaluation method for the product and comparative product alone (artificial urine water absorption)
A practical product, a comparative product, and 200 ml of artificial urine cut into 6 cm × 7 cm were placed in a 300 ml beaker, and left for 30 minutes to sufficiently swell the practical products 1, 2, and comparative product 1 with artificial urine. Next, after removing the adhered water of the product and the comparative product with a 200 mesh filter cloth, the artificial urine water absorption A (kg / m ² ) was calculated according to the following formula.
[0061]
A = (W1-W2) /0.42
In the formula, W1 is the mass of the product after water absorption and the comparative product, and W2 is the mass of the product before water absorption and the comparative product.
[0062]
(Artificial urine water absorption speed)
A practical product or a comparative product cut into 6 cm × 7 cm in a 300 ml beaker and 200 ml of artificial urine were placed and allowed to stand for 5 minutes to swell with artificial urine. Next, after removing artificial urine adhering to the embodiment product or the comparative product swollen with a 200 mesh filter cloth, the artificial urine water absorption rate A (kg / m ² ) was calculated according to the above formula.
[0063]
The composition of the artificial urine (per 10 kg) is urea / NaCl / MgSO ₄ .7H ₂ O / CaCl ₂ .2H ₂ O / pure water = 200 g / 80 g / 8.0 g / 3.0 g / 9709 g.
[0064]
The results are shown in Table 1.
[0065]
[Table 1]

[0066]
B. Incontinence liner evaluation method (How to make an incontinence liner for evaluation)
Examples 1 and 2 and a comparative product cut out to 4.5 cm × 14 cm were sandwiched between a nonwoven fabric and a polyethylene sheet, and the periphery was fixed with a stapler to obtain a sample for evaluating a paper diaper.
[0067]
FIG. 1 shows the configuration of the manufactured incontinence liner. In FIG. 1, (a) is an incontinence liner produced using the implementation product 1, (b) is an incontinence liner produced using the implementation product 2, and (c) is an incontinence liner produced using a comparative product. In FIG. 1, 2 is a nonwoven fabric, 4 is a water absorbing sheet, 6 is toilet paper, 8 is a nonwoven fabric, and 10 is a polyethylene sheet.
[0068]
(Incontinence liner evaluation method)
An incontinence liner was placed on a horizontal plane, and a measurement cylinder (φ26 mm) was placed in the center, and 5 ml of artificial urine (colored in blue) was poured into it at once. The time required for the artificial urine in the cylinder to be absorbed into the incontinence liner was measured, and this was defined as the first water absorption time. After standing for 3 minutes, the measurement cylinder was placed again in the center of the incontinence liner, 5 ml of artificial urine was poured all at once, and the second water absorption time was measured in the same manner. After leaving for 2 minutes, 10 pieces of kitchen paper (W1 g) cut into 4 cm × 5 cm whose mass was measured in advance was placed on the center of the incontinence liner. Thereafter, an additional 100 g (4 cm × 5 cm) weight was placed on the kitchen paper and pressurized for 10 seconds. The kitchen paper was removed and the mass was measured (W2g). The return amount was determined by the following formula.
[0069]
Return amount = W2-W1
After measuring the amount of reversion, the incontinence liner was opened, and the diffusion distance of the artificial urine was measured with a ruler to determine the diffusion distance.
[0070]
[Table 2]

[0071]
【The invention's effect】
In the present invention, since the water-absorbent sheet having a large number of fine water-absorbent resin particles fixed to the fibrous base material and the fibrous base material sheet are laminated and integrated into a composite sheet, the water-absorbent resin particles are Efficiently draws out the potential water absorption capability and can absorb a large amount of water rapidly. Furthermore, when the uneven | corrugated pattern by heat compression is formed in the surface of this water absorptive composite sheet, a higher water absorption capability can be exhibited, without impairing a softness | flexibility.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the configuration of an incontinence liner, where (a) shows the case where the water absorbent composite sheet of Example 1 is used, and (b) shows the case where the water absorbent composite sheet of Example 2 is used. (C) shows the case of using the water absorbent sheet of Comparative Example 1.
[Explanation of symbols]
2 Nonwoven fabric 4 Water absorbent sheet 6 Toilet paper 8 Nonwoven fabric 10 Polyethylene sheet

Claims (3)

Nonwoven fabric of non-hydrophilic resin having a basis weight of 10 to 100 g / m ² manufactured using a base fiber having a fineness of 1.0 to 20 dtex and a fiber length of 25 to 128 mm, and subjected to hydrophilization treatment and raising treatment and absorbent sheet obtained by sticking by the water-absorbing resin particles with a particle size 30~300μm to the substrate is polymerized by attaching aqueous monomer solution droplets ² 0~300g / m 2 wherein the fibrous base material, wherein It consists of a fibrous base material sheet having a depth of 0.01 to 1 mm and having a concavo-convex pattern formed of hydrophilic fibers adhered to at least one surface of a water-absorbent sheet or synthetic fibers subjected to a hydrophilic treatment. Water-absorbent composite sheet characterized by Fineness 1.0～20Dtex, the fiber length 25~128mm nonhydrophilic basis weight 10 to 100 g / ^{m 2} made of resin hydrophilic treatment of decorated nonwoven made with the base fibers at 80 to 110 ° C. 20 Heating for ~ 60 seconds and raising the hair;
An average particle is obtained by spraying an aqueous solution containing 40 to 60% by mass of a mixture of acrylic acid and acrylate in which 20 to 90 mol% of acrylic acid is converted to an alkali metal salt and a polymerization initiator on the nonwoven fabric. A step of supporting particles having a diameter of 50 to 500 μm ;
Wherein by an aqueous solution containing a mixture of acrylic acid and acrylate and a polymerization initiator to nonwoven heating and / or light irradiation to be carried on the particulate, by polymerizing a mixture of acrylic acid and acrylate, water Obtaining an adhesive sheet;
A step of attaching the fibrous base sheet to the water-absorbent sheet by heat compression using a pair of heated rolls having a concavo-convex pattern formed on at least one roll , and
The manufacturing method of the water absorptive composite sheet of Claim 1 which has these. The method for producing a water-absorbent composite sheet according to claim 2, wherein the surface of at least one of the rolls has a concavo-convex pattern.

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