JP5039513B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article including an absorbent body that includes a water-absorbing polymer.

  Absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads widely use water-absorbing polymers for the purpose of absorbing bodily fluids such as urine. Examples of the water-absorbing polymer include a crosslinked polyacrylic acid partial neutralized product, a hydrolyzate of starch-acrylic acid graft polymer, a saponified vinyl acetate-acrylic acid ester copolymer, an acrylonitrile copolymer or an acrylamide copolymer. Polymer hydrolysates or cross-linked products thereof, and cationic monomers are used as main raw materials.

  Conventionally, water-absorbing polymers have been required to have excellent physical properties such as excellent water absorption and water absorption rate when in contact with aqueous liquids such as body fluids, high absorption capacity under pressure and liquid permeability, Many patent documents specifying various physical properties of the water-absorbing polymer have been filed (for example, see Patent Documents 1 to 3).

  However, a conventional water-absorbent article using a water-absorbing polymer has a problem that so-called gel blocking, in which the liquid passage in the absorbent body is blocked by the absorbent polymer swollen by absorption of the liquid, is likely to occur. For this reason, even if the water-absorbent article using the conventional water-absorbing polymer shows good liquid absorbability at the time of the first bodily fluid absorption, the liquid absorbency is greatly lowered at the second and subsequent bodily fluid absorption. As a result, there is a problem in that the liquid flows through the surface of the absorber without being absorbed and causes liquid leakage.

JP 2001-258933 A JP 2001-252307 A Japanese National Publication No. 9-510889

  Accordingly, an object of the present invention is to provide an absorbent article having a water-absorbing polymer having a high water absorption rate and excellent liquid permeability, excellent absorption performance, and hardly causing liquid leakage.

  The present invention relates to an absorbent article comprising a vertically long absorbent comprising a water-absorbing polymer, wherein the water-absorbing polymer is absorbed under a pressure of 2.0 kPa at a water absorption rate of 20 seconds or less by a vortex method. The object is achieved by providing an absorbent article having a liquid velocity of 60 ml / min or more.

  The absorbent article of the present invention is excellent in the absorption performance of body fluids such as urine, and hardly leaks.

Hereinafter, the absorptive article of the present invention is explained based on the desirable embodiment with reference to drawings.
The disposable diaper as 1st Embodiment of this invention is shown by FIG. 2 is a cross-sectional view taken along line II in FIG. In FIG. 2, the portion that was broken in FIG. 1 is shown in a state where it is not broken.

  The diaper 1 of the first embodiment includes a liquid-permeable top sheet 2, a vertically long absorbent body 3 including a water-absorbing polymer 10, and a liquid-impermeable or water-repellent and moisture-permeable back sheet 4. And is formed substantially vertically long. The absorbent body 3 is disposed between the top sheet 2 and the back sheet 4 with its longitudinal direction coinciding with the longitudinal direction L of the diaper 1.

  The absorbent body 3 has an upper layer 30 having liquid permeability and a lower layer 31 disposed on the non-skin contact surface side of the upper layer 30, and the water absorbing polymer 10 is sandwiched between the upper layer 30 and the lower layer 31. is doing. The absorber 3 is formed by spraying a large number of water-absorbing polymers 10 between the upper layer 30 and the lower layer 31. The absorber 3 (the lower layer 31) and the back sheet 4 are joined by a known joining means such as a hot melt adhesive. A large number of water-absorbing polymers 10 are adhered to each other and / or the upper layer 30 and the lower layer 31 by expressing the tackiness of the polymers themselves. It does not contain a binder for attaching the polymers 10 to each other or to the upper layer 30 or the lower layer 31.

  The water-absorbing polymer 10 is usually sprayed between the upper layer 30 and the lower layer 31 by spraying water on the upper layer 30 or the lower layer 31 or the water-absorbing polymer 10 itself, or by the water-absorbing polymer itself. If the water-absorbing polymer 10 has a water content of more than 10%, preferably more than 15%, the water-absorbing polymer 10 has high hygroscopicity, and the upper layer 30 and the lower layer 31 It is possible to absorb the moisture in the air after being sprayed between the two and express adhesiveness, so that it is not necessary to spray water.

Hereinafter, the water-absorbing polymer 10 will be described.
The water-absorbing polymer 10 has a water absorption rate of 20 seconds or less, preferably 5 to 20 seconds, more preferably 5 to 15 seconds by a vortex method (VORTEX method). The vortex method is known as a method for showing the ability to fix a liquid when the water-absorbing polymer is forcibly exposed to the liquid. If the water absorption speed exceeds 20 seconds, the liquid will remain on the surface of the absorber for a long time, causing leakage, increasing the evaporation of water from the surface, or wetting the skin, which may cause irritation. There is. In addition, in this invention, since the evaluation of the water absorption rate by a vortex method is evaluated by measuring time, it is considered that a water absorption rate is so quick that measurement time is short. The water absorption rate by the vortex method is measured as follows.

(Measurement method of water absorption rate by vortex method)
In a 100 mL glass beaker, 50 mL of physiological saline (0.9 wt% sodium chloride water using ion exchange water) and a magnetic stirrer chip (center diameter 8 mm, both ends diameter 7 mm, length 30 mm, surface is fluorine) The resin beaker is placed, and the beaker is placed on a magnetic stirrer (HPS-100 manufactured by ASONE). The rotational speed of the magnetic stirrer is adjusted to 600 ± 60 rpm, and the physiological saline is stirred. 2.0 g of the water-absorbing polymer as a measurement sample is put into the liquid at the center of the vortex of the saline solution being stirred, and the water absorption rate (seconds) of the water-absorbing polymer is measured in accordance with JIS K 7224 (1996). taking measurement. Specifically, the stopwatch is started when the absorption of the water-absorbing polymer into the beaker is completed, and stopped when the stirrer tip is covered with the test liquid (when the vortex disappears and the liquid surface becomes flat). Stop the watch and record the time (in seconds) as the water absorption rate by vortex method. In the measurement, n = 5 was measured, the values at each of the upper and lower points were deleted, and the average value of the remaining three points was taken as the measured value. These measurements are performed at 23 ± 2 ° C. and a humidity of 50 ± 5%, and the samples are stored for 24 hours or more in the same environment before the measurement.

For water-absorbing polymers incorporated in products (absorbent articles), various properties including water absorption rate by vortex method (pressure passing through under pressure at 2.0 kPa, water absorption by centrifugal dehydration method, saturated water absorption) When evaluating the amount, etc.), the water-absorbing polymer taken out from the product as described below is the object of evaluation.
That is, the surface sheet, the back sheet, the covering sheet, etc. are removed from the product, 1) only the water-absorbing polymer, or 2) the water-absorbing polymer and the fibrous material (fiber component constituting the absorbent body together with the water-absorbing polymer). Use only the mixture. In the case of 1), the obtained water-absorbing polymer can be used for various evaluations as it is. In the case of 2), the mixture is divided into a water-absorbing polymer and a fibrous material using a sieve. This sieving operation uses a sieve that allows the water-absorbing polymer to pass but does not allow the fibrous material to pass through, and after sieving only the water-absorbing polymer while rubbing the mixture placed on the sieve by hand, it is sieved off. The water-absorbing polymer is screened again with the fibrous material remaining on the screen. A water-absorbing polymer taken out from at least 5 products by such sieving operation is used for various evaluations.

Further, the water-absorbing polymer 10 has a liquid passing rate under pressure of 2.0 kPa of 60 ml / min or more, preferably 60 to 500 ml / min, more preferably 80 to 500 ml / min, and 100 to 400 ml / min is further increased. preferable. Here, the load of 2.0 kPa substantially corresponds to the body pressure applied to the absorbent body when the absorbent article is worn. When the value of the liquid absorption rate of the water-absorbing polymer is less than 60 ml / min, the water-absorbing polymers saturated and swollen by the liquid absorption adhere to each other under load, thereby preventing the passage of the liquid and causing gel blocking. Cheap. Therefore, by making the liquid-absorbing polymer 10 flow rate within the above range, gel blocking is less likely to occur, and when a large amount of excreta is excreted at once, it is an example of an older infant or adult. As can be seen, even when the excretion rate is fast, and even when the absorber is made thinner, the liquid can be sufficiently fixed, and liquid leakage is less likely to occur.
Moreover, setting the preferable upper limit of the liquid flow rate to 500 ml / min as described above is particularly effective when the ratio of the hydrophilic fibers in the absorber is less than 50% by weight. That is, when the ratio of the hydrophilic fiber in the absorbent body 3 is less than 50% by weight, if the value of the liquid passing rate of the water absorbent polymer 10 exceeds 500 ml / min, the absorbent polymer 10 sufficiently absorbs the liquid. Before absorption, the body fluid diffuses in the absorber 3 and reaches the end of the absorber 3 where leakage tends to occur. By adjusting the liquid flow rate of the water absorbent polymer 10 to 500 ml / min or less. The disadvantage that the liquid easily reaches the end of the absorber 3 is less likely to occur.
The liquid passing rate under pressure is measured using a measuring method and a measuring apparatus described in JP-A-2003-235889. Specifically, the flow rate under pressure at 2.0 kPa is measured by the following procedure. These measurements are performed at 23 ± 2 ° C. and a humidity of 50 ± 5%, and the measurement is performed after storing the sample in the same environment for 24 hours or more before the measurement.

(Measurement method of liquid flow rate under pressure)
In a 200 mL glass beaker, a sufficient amount of physiological saline (0.9 wt% sodium chloride water using ion-exchanged water) to swell the water-absorbing polymer 0.32 ± 0.005 g as a measurement sample, for example, water absorption Immerse in physiological saline 5 times or more of the saturated absorption of the functional polymer and leave it for 30 minutes.
Separately, at the lower end of an opening of a vertically standing cylinder (inner diameter 25.4 mm), a wire mesh (mesh opening 150 μm, biocolumn sintered stainless steel filter 30SUS sold by Sansho Co., Ltd.) and a capillary (with an inner diameter of 2 mm) ( A filtration cylindrical tube having an inner diameter of 4 mm and a length of 8 cm) is prepared, and the contents of the beaker including the swollen measurement sample are put into the cylindrical tube with the cock closed. Open the cock and adjust the liquid level in the filtration cylinder to 5 cm above the 60 mL scale line. Next, a cylindrical rod having a diameter of 2 mm with a wire mesh having an opening of 150 μm and a diameter of 25 mm is inserted into the filtration cylindrical tube so that the wire mesh and the measurement sample are in contact with each other. Place a weight so that the load of. After standing for 1 minute in this state, the cock is opened to flow the liquid, and the time until the liquid level in the filtration cylindrical tube reaches the 40 mL scale line from the 60 mL scale line (that is, 20 mL of liquid passes) (T1). (Seconds) is measured with a stopwatch. Using the measured time T1 (seconds), the liquid flow rate under pressure at 2.0 kPa is calculated from the following equation. In the formula, T0 (seconds) is a value obtained by measuring the time required for 20 ml of physiological saline to pass through the wire mesh without putting the measurement sample in the filtering cylindrical tube.
Flow rate under pressure (ml / min) = 20 × 60 / (T1-T0)
The measurement was performed 5 times (n = 5), the values at each of the upper and lower points were deleted, and the average value of the remaining three points was taken as the measured value.

  The water-absorbing polymer 10 having a water absorption rate of 20 seconds or less by vortex method and a liquid passing rate under pressure of 2.0 kPa of 60 ml / min or higher has a high water absorption rate and high liquid permeability, and hardly generates gel blocking. Therefore, the absorbent body 3 including the water-absorbing polymer 10 can absorb the liquid at the spot without spreading the liquid in the first body fluid excretion, and also in the second and subsequent body fluid excretion. Since the liquid can be absorbed firmly and the liquid can smoothly flow through the gaps of the swollen water-absorbing polymer 10, the liquid can be diffused into the absorbent body 3 and has high liquid absorbability.

  The water-absorbing polymer 10 has a water absorption rate of 20 seconds or less by vortex method and a liquid passing rate under pressure of 2.0 kPa of 60 ml / min or more, and further has a water absorption amount (centrifugal retention amount) by centrifugal dehydration method. ) Is preferably 20 g / g or more, more preferably 30 g / g or more, more preferably 40 g / g or more. When the centrifugal retention amount of the water-absorbing polymer is 20 g / g or more, liquid return and liquid bleeding due to pressurization such as the movement of the wearer are reduced, so that the effect of making it difficult to wet the skin is exhibited. In addition, the larger the value of the centrifugal retention amount of the water-absorbing polymer, the better, but 60 g / g is usually sufficient.

The water-absorbing polymer 10 preferably has a saturated water absorption of 40 g / g or more, more preferably 50 g / g or more, and more preferably 60 g / g or more. If the saturated water absorption amount of the water-absorbing polymer is 40 g / g or more, the absorption capacity per unit area increases, so that the absorber can be made thinner, and the space between adjacent water-absorbing polymers after liquid absorption is also possible. Therefore, the effect of hardly inhibiting the diffusion of the liquid in the absorber is exhibited. The saturated water absorption value of the water-absorbing polymer is preferably as large as possible, but 80 g / g is usually sufficient.
The saturated water absorption amount of the water-absorbing polymer and the water absorption amount by centrifugal dehydration are respectively measured as follows. These measurements are performed at 23 ± 2 ° C. and a humidity of 50 ± 5%, and the measurement is performed after storing the sample in the same environment for 24 hours or more before the measurement.

(Measurement method of saturated water absorption)
The saturated water absorption is measured according to JIS K 7223 (1996). Nylon woven fabric (mesh opening 250, sold by Sanriki Manufacturing Co., Ltd., product name: nylon net, standard: 250 x mesh width x 30 m) is cut into a rectangle with a width of 10 cm and a length of 40 cm and folded in half at the center in the longitudinal direction. Both ends are heat-sealed to produce a nylon bag having a width of 10 cm (inner dimension: 9 cm) and a length of 20 cm. 1.00 g of the water-absorbing polymer as a measurement sample is precisely weighed and placed uniformly at the bottom of the produced nylon bag. The nylon bag containing the sample is immersed in physiological saline (0.9 wt% sodium chloride water using ion exchange water) for 1 hour. After 1 hour, the nylon bag is taken out from the physiological saline, suspended in the vertical state for 1 hour and drained, and then the weight of the nylon bag is measured. The target saturated water absorption is calculated from the following equation.
Saturated water absorption amount of physiological saline (g / g) = (a−b−c) / c; where a is the total weight (g) of the sample and the nylon bag after water absorption, b is before water absorption of the nylon bag ( Weight (g) at the time of drying, and c represents the weight (g) of the sample before water absorption (at the time of drying). The measurement was performed 5 times (n = 5), the values at each of the upper and lower points were deleted, and the average value of the remaining three points was taken as the measured value.

(Measurement method of water absorption by centrifugal dehydration method)
In the above (method for measuring saturated water absorption), the nylon bag after draining is dehydrated in a centrifugal dehydrator. The dehydration condition is 143 G (800 rpm) for 10 minutes. After dehydration, the weight of the sample is measured, and the target water absorption is calculated according to the following formula.
Water absorption by centrifugal dehydration method (g / g) = (a′−b−c) / c; where a ′ is the total weight (g) of the sample and nylon bag after centrifugal dehydration, and b is the water absorption of the nylon bag. The weight (g) before (when dried) and c represents the weight (g) before water absorption (when dried) of the sample. The measurement was performed 5 times (n = 5), the values at each of the upper and lower points were deleted, and the average value of the remaining three points was taken as the measured value.

  The above-mentioned four characteristics (water absorption rate by vortex method, liquid passing rate under pressure at 2.0 kPa, water absorption amount by centrifugal dehydration method, saturated water absorption amount) are adjusted to the above ranges respectively. By using it as a component, it is possible to obtain an absorbent body that absorbs excretory fluid quickly and has little liquid return or leakage. The absorbent obtained in this way is capable of quickly absorbing excretory fluid and effectively reducing fluid return and leakage even when there is a large amount of excretion at once or when the excretion rate is fast. The present invention can be suitably used for absorbent articles for infants and adults, or absorbent articles that are intended for bedtime and nighttime waking. Moreover, since the thickness of the absorber can be reduced by using the water-absorbing polymer in which the above-described four characteristics are adjusted to the above-described ranges, for example, exercise of an older infant with a large amount of activity It is possible to obtain a thin absorbent body that does not obstruct the skin, or a thin absorbent body that does not make it difficult to wear a diaper even when an elderly person goes out.

  The above four characteristics (water absorption rate by vortex method, liquid passing rate under pressure at 2.0 kPa, water absorption amount by centrifugal dehydration method, saturated water absorption amount) are designed according to the composition, shape, particle size, etc. of the water-absorbing polymer. be able to. The composition (material) of the water-absorbing polymer is a particularly important factor in adjusting each characteristic to the above-described range.

  In the present invention, examples of the water-absorbing polymer material include polyacrylic acid soda, (acrylic acid-vinyl alcohol) copolymer, polyacrylic acid soda crosslinked product, (starch-acrylic acid) graft polymer, (isobutylene). -Maleic anhydride) Copolymers and saponified products thereof, synthetic resin systems such as potassium polyacrylate and cesium polyacrylate; using natural or biological materials such as starch, cellulose and derivatives thereof, and crosslinked amino acids Can do. When a natural or biological substance is used as the material of the water-absorbing polymer and the main chain is formed from the substance, the water content of the water-absorbing polymer, that is, the hygroscopic property of the water-absorbing polymer is a synthetic resin material. Therefore, the fixability to other members such as fibers and sheets is increased by the adhesiveness of the water-absorbing polymer itself. Thereby, since the material for fixing the water-absorbing polymer, for example, hot melt and extra fibers can be reduced, the absorber can be made thinner and more flexible. Furthermore, it is desirable that the water-absorbing polymer has an ionic functional group such as a sulfone group or a carboxyl group in order to increase the water absorption ratio and the water absorption rate.

Hereinafter, a water-absorbing polymer having polyacrylic acid as the main chain, which is a water-absorbing polymer that can be used in the present invention, will be described.
In order to obtain a water-absorbing polymer having a liquid passing speed under pressure of 2.0 kPa in the above range, for example, the cross-linking density of the inside and the surface of the water-absorbing polymer is adjusted, a gradient is provided in the cross-linking density, The particle shape of the conductive polymer may be adjusted. In particular, by adopting a reverse phase suspension polymerization polymerization method using an anionic surfactant described in Japanese Patent No. 2721658, which is a prior application of the present applicant, as a dispersant, a desired flow rate under pressure is applied. A water-absorbing polymer having is obtained.
In addition, it is possible to obtain a water-absorbing polymer whose water absorption rate by the vortex method is in the above range by controlling the surface shape of the water-absorbing polymer (in the present invention, the surface shape is evaluated by bulk density) and the particle size. Become. That is, the bulk density of the water-absorbing polymer used in the present invention is preferably 0.5 to 0.8 g / cm ³ from the viewpoint of ensuring liquid permeability and increasing the absorption rate, and is preferably 0.55 to 0.7 g / cm ³ is more preferable.

In the present invention, a water-absorbing polymer having a polyamino acid as the main chain can be used. Hereinafter, the water-absorbing polymer having the polyamino acid as the main chain will be described.
Here, the polyamino acid is an amino acid homopolymer, a copolymer of an amino acid and another monomer component, or a copolymer of a plurality of types of amino acids. The main chain is a portion excluding the crosslinked portion of the polymer. Since the polyamino acid has an amide bond having hydrophilicity in the main chain, the water-absorbing polymer having the polyamino acid as the main chain has high liquid wettability. By using a water-absorbing polymer with high liquid wettability, it is possible to obtain an absorbent article having high liquid absorbency, more specifically, high absorption speed and small liquid diffusion area. It becomes.

  The polyamino acid used in the present invention is preferably a crosslinked polyamino acid partially crosslinked. A water-absorbing polymer formed from a crosslinked polyamino acid is superior in terms of water absorption, retention, and urine stability compared to a water-absorbing polymer formed from a non-crosslinked polyamino acid. The main chain of the crosslinked polyamino acid consists of a polypeptide obtained by dehydration condensation of amino acids. When the crosslinked polyamino acid is a copolymer, the polymerization mode may be a block copolymer, a random copolymer, or a graft copolymer.

  Examples of the amino acid constituting the polyamino acid used in the present invention include alanine, valine, leucine, isoleucine, methionine, tryptophan, phenylalanine, proline, glycine, serine, threonine, cysteine, tyrosine, asparagine, glutamine, lysine, histidine, Arginine, aspartic acid, glutamic acid, etc. are mentioned. The amino acid may be an optically active substance (L form, D form) or a racemic form.

  When the polyamino acid is a copolymer of an amino acid and another monomer component other than an amino acid, examples of the other monomer component include aminocarboxylic acid, aminosulfonic acid, aminophosphonic acid, and hydroxycarboxylic acid. Examples include acid, mercaptocarboxylic acid, mercaptosulfonic acid, mercaptophosphonic acid and the like. Also, polyvalent amine, polyhydric alcohol, polyvalent thiol, polyvalent carboxylic acid, polyvalent sulfonic acid, polyvalent phosphonic acid, polyvalent hydrazine compound, polyvalent carbamoyl compound, polyvalent sulfonamide compound, polyvalent phosphonamide compound Polyvalent epoxy compounds, polyvalent isocyanate compounds, polyvalent isothiocyanate compounds, polyvalent aziridine compounds, polyvalent carbamate compounds, polyvalent carbamic acid compounds, polyvalent oxazoline compounds, polyvalent reactive unsaturated bond compounds, etc. Can be mentioned.

  The side chain group of the polyamino acid used in the present invention may be a group in an amino acid residue as it is or a group (pendant group) converted to another group. The pendant group in this case is a group bonded to the polyamino acid main chain via an amide bond, an ester bond, a thioester bond, or the like. For example, in the case of polyglutamic acid, examples of the side chain group include a carboxyl group in an amino acid residue, and examples of the pendant group include a hydrocarbon group having a carboxyl group and a hydrocarbon group having a sulfonic acid group. Moreover, the bonding position of the side chain group is not particularly limited. For example, in the case of polyaspartic acid, the carboxyl group which is a side chain group may be bonded at the α-position or at the β-position in the amino acid residue. In the case of polyglutamic acid, the carboxyl group which is a side chain group may be bonded at the α-position or the γ-position in the amino acid residue.

  When the side chain group of the polyamino acid has an acidic ionic group such as a carboxyl group or a sulfonic acid group, the polyamino acid is preferably a neutralized salt type polyamino acid in which the acidic ionic group is neutralized. It is preferable from the viewpoint of developing water absorption characteristics and storage stability. In neutralizing the acidic ionic group, it is preferable to increase the neutralization rate as much as possible. As a neutralization rate, 30-100 mol% is preferable and 50-99 mol% is more preferable. Examples of the neutralized salt include alkali metal (Na, K, etc.) salts, alkaline earth metal (Mg, Ca, etc.) salts, ammonium salts, amine salts and the like.

  The polymerization degree of the polyamino acid used in the present invention, that is, the number of repeating units constituting the polymer main chain is preferably in the range of 100,000 to 100,000, more preferably in the range of 100 to 50,000. If the degree of polymerization of the polyamino acid is lower than this range, the desired water absorption characteristics cannot be expressed, and if it is higher than this range, the viscosity of the solution increases and the workability decreases.

  The cross-linked structure in the cross-linked polyamino acid, which is a preferred polyamino acid used in the present invention, is not particularly limited. For example, a structure in which a carboxyl group in the amino acid residue of the cross-linked polyamino acid reacts or associates, or a pendant group Examples thereof include a structure in which a polar group having a crosslinking agent reacts or associates, and a self-crosslinked body in which polyamino acid main chains are directly bonded to each other.

  The compound used as the crosslinking agent is not particularly limited. For example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, polypropylene glycol, 1,4-butanediol, Polyhydric alcohols such as 1,5-pentanediol, 1,6-hexanediol, neopentyl alcohol, trimethylolpropane, diethanolamine, triethanolamine, polyvinyl alcohol, pentaerythritol, sorbitol; sorbitan, glucose, mannitol, mannitan, Polyhydric alcohols such as sucrose and glucose, ethylene glycol diglycidyl ether, polyethylene glycol glycidyl ether, Polyvalent glycidyl compounds such as roll polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, propylene glycol polyglycidyl ether, polypropylene polyglycidyl ether; 2,2'-bishydroxymethylbutanol-tris Multivalent aziridines such as [3- (1-aziridinyl) propionate], 1,6-hexamethylenediethyleneurea, diphenylmethane-bis-4,4′-N, N′-diethyleneurea; epichlorohydrin, epibromohydrin, α -Haloepoxy compounds such as methylchlorohydrin; ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexa Polyhydric amines such as lysine, lysine, polylysine, polyethyleneimine, polyallylamine, polydiallylamine, polyamide polyamine epichlorohydrin; polyvalent isocyanates such as 2,4-toluylene diisocyanate and hexamethylene diisocyanate; magnesium, calcium, barium, zinc, iron And salts or hydroxides of polyvalent metals such as trivalent metals such as aluminum, iron, titanium, and zirconium.

  There is no restriction | limiting in particular about the polyamino acid used for this invention, The thing by various manufacturing methods is used. Examples thereof include a culture method using a microorganism, a chemical synthesis method, and the like. Moreover, the manufacturing method of bridge | crosslinking polyamino acid is not specifically limited, either. For example, a method of cross-linking acidic amino acids to obtain a hydrogel (US Pat. No. 3,948,863; Japanese Examined Patent Publication No. 52-41309, JP-A-5-279416), a method of irradiating polyglutamic acid with γ rays (Polymer Papers, 50 Vol. 10, p. 755 (1993), Patent 203493, Patent 3416774, Patent 3715414, JP 2005-314489), Cross-linking of polyglutamic acid with a cross-linking agent (JP-A-11-343339, JP-A-2003- 192794, JP-A-2005-179534, JP-A-2001-181387, polyaspartic acid, a method of reacting aspartic acid with a crosslinking agent by heat (Japanese Patent Publication No. 6-506244; US Pat. Nos. 5,247,068 and 5,284,936). No. 7, JP-A-7-309943, JP-A-8-59820 ), And the like can be used.

  The shape of the water-absorbing polymer 10 is not particularly limited, and may be spherical (particulate), fibrous, indefinite shape, or an aggregate thereof. In the case of a spherical or irregular shape, the average particle size of the water-absorbing polymer 10 is preferably 50 to 800 μm, more preferably 100 to 500 μm. Particularly preferred is a water-absorbing polymer having an average particle size in the range of 100 to 350 μm and a proportion of particles having a particle size of 500 μm or more being less than 20%. Here, the average particle diameter of the water-absorbing polymer is measured by the following method. 50 g of the water-absorbing polymer is sieved using a shaker (ASche type, AS200 type). The sieve used here is a standard sieve manufactured by Tokyo Screen Co., Ltd. defined by JIS Z 8801, and has an opening of 850, 600, 500, 355, 300, 250, 150. The shaking conditions are 50 Hz, amplitude 0.5 mm, and 10 minutes. The measurement is performed three times, and the average value is defined as the weight on the sieve. Divide the obtained weight on each sieve by 50 to determine the relative frequency, draw a particle size cumulative curve, and use the particle size corresponding to the median cumulative value (50%) of the cumulative curve as the average particle size.

The distribution amount of the water-absorbing polymer 10 in the absorber 3 can be adjusted according to the application of the absorber 3. For example, when it is used as an absorbent body for disposable diapers for infants, it is preferably 50 to 500 g / m ² , particularly preferably 100 to 300 g / m ² . When used as an absorbent body for adult disposable diapers, it is preferably 10 to 800 g / m ² , particularly 50 to 500 g / m ² . Moreover, although the absorber 3 is an absorber of the disposable diaper 1, it can also be used as an absorbent body of a sanitary napkin or an incontinence pad, and when used as an absorbent body of a sanitary napkin, 10 to 200 g / m. ² and particularly 15 to 100 g / m ² , and when used as an incontinence pad absorber, 10 to 500 g / m ² , particularly 15 to 350 g / m ² is preferable.

As described above, each of the upper layer 30 and the lower layer 31 sandwiching the water-absorbing polymer 10 has liquid permeability. As the upper layer 30 and the lower layer 31, those formed from a material having liquid permeability can be used. Examples of the liquid permeable material include nonwoven fabric, paper, perforated film, fluff pulp and the like. Among these, nonwoven fabric, paper, and fluff pulp are particularly preferable from the viewpoint of liquid permeability and water absorption. Non-woven fabrics such as air-through nonwoven fabric, thermal bond nonwoven fabric, spunbond nonwoven fabric, spunbond-meltblown-spunbond (SMS) nonwoven fabric, spunbond-meltblown-meltblown-spunbond (SMMS) nonwoven fabric, etc. Or airlaid nonwoven fabric, spunlace, etc. are mentioned.
Note that the lower layer 31 may not have liquid permeability. As a material for forming the lower layer 31 when the liquid permeability is not imparted to the lower layer 31, for example, a material that can be used as the liquid-impermeable or water-repellent and moisture-permeable back sheet 4 (described later) can be used. .

When the upper layer 30 is made of a nonwoven fabric, the basis weight of the upper layer 30 is preferably 5 to 50 g / m ² , more preferably 10 to 40 g / m ² , and the thickness is preferably 0.1 to 5 mm, more preferably. Is 0.1 to 3 mm. When the upper layer 30 is made of fluff pulp, the basis weight of the upper layer 30 is preferably 10 to 500 g / m ² , more preferably 30 to 300 g / m ² , and the thickness is preferably 0.5 to 5 mm, Preferably it is 1-3 mm. When the upper layer 30 is made of paper, the basis weight of the upper layer 30 is preferably 5 to 30 g / m ² , more preferably 5 to 20 g / m ² , and the thickness is preferably 0.01 to 3 mm, more preferably. Is 0.01-1 mm.

If the lower layer 31 is made of a nonwoven fabric, the basis weight of the lower layer 31 is preferably 5 to 50 g / m ^2, more preferably a 20 to 40 g / m ^2, thickness is preferably 0.1 to 5 mm, more preferably Is 0.1 to 3 mm. When the lower layer 31 is made of fluff pulp, the basis weight of the lower layer 31 is preferably 10 to 500 g / m ² , more preferably 30 to 300 g / m ² , and the thickness is preferably 0.5 to 5 mm, Preferably it is 1-3 mm. When the lower layer 31 is made of paper, the basis weight of the lower layer 31 is preferably 5 to 30 g / m ² , more preferably 5 to 20 g / m ² , and the thickness is preferably 0.1 to 3 mm, more preferably. Is 0.1-1 mm.

  In addition to the water-absorbing polymer 10, pulp fibers can be included between the upper layer 30 and the lower layer 31. In conventional absorbents based on pulp fibers, pulp fibers have the ability to temporarily store liquids, spread liquids, and relieve pressure, and there is a limit to the reduction in the amount of pulp fibers used. It was. On the other hand, since the water-absorbing polymer 10 used in the present invention has a high water absorption rate and excellent liquid permeability as described above, the amount of pulp fiber used can be increased by using the water-absorbing polymer 10 as a constituent component of the absorber. Can be reduced as compared with the prior art, and the concentration (distribution amount) of the water-absorbing polymer in the absorber can be adjusted to a high concentration. Here, high concentration means that the weight ratio of pulp / water-absorbing polymer is 50/50 to 0/100. Thus, by making the density | concentration of a water absorptive polymer high, the absorber which has the thin thickness and can provide the absorbent article which was excellent in thickness while having the outstanding liquid absorptivity is obtained.

Hereinafter, the diaper 1 of 1st Embodiment is further demonstrated.
The diaper 1 has an hourglass-like shape with a central portion in the longitudinal direction corresponding to the crotch portion as a whole. The top sheet 2 and the back sheet 4 respectively extend outward from the left and right side edges and the front and rear ends of the absorber 3. The top sheet 2 has a width direction S smaller than the back sheet 4 in the width direction. The diaper 1 is an unfolded diaper, and a pair of fastening tapes FT are attached to both side edges at one end in the longitudinal direction L. Further, a landing tape LT is attached on the back sheet 4 at the other end.

  The diaper 1 includes a three-dimensional gather that can rise above the widthwise side edge of the absorber 3. That is, on each side of the diaper 1 in the longitudinal direction L, a sheet material 60 for forming a three-dimensional gather having the elastic member 6 is disposed to form a three-dimensional gather. In addition, on one side of the diaper 1 in the longitudinal direction L, a pair of left and right or one (two in the first embodiment) elastic members 7 and 7 for forming leg gathers are arranged, and the leg gathers are arranged. Is formed. The elastic members 7 for forming leg gathers are arranged in a substantially linear shape in an extended state in the leg flaps extending outward from both longitudinal side edges of the absorber 3.

  One or a plurality of the elastic members 6 (three in the first embodiment) are fixed to one side edge of the sheet material 60 for forming a three-dimensional gather. The sheet material 60 is joined to the surface sheet 2 along the longitudinal direction L of the diaper 1 at positions outside the left and right side edges of the absorbent body 3 in the width direction S. The rising base end portion 61 of FIG. The sheet material 60 extends outward from the rising base end portion 61 in the width direction S of the diaper 1, and is joined to the back sheet 4 at the extended portion. The sheet material 60 is bonded onto the top sheet 2 at the front and rear end portions 62 and 63 in the diaper longitudinal direction L.

  As the sheet material 60 for forming a three-dimensional gather, a liquid-impermeable or water-repellent and moisture-permeable material is preferably used. Examples of the sheet material 60 include a liquid impermeable or water repellent porous resin film, a liquid impermeable or water repellent nonwoven fabric, or a laminate of the porous resin film and the nonwoven fabric. Examples of the nonwoven fabric include thermal bond nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, and SMMS nonwoven fabric. The basis weight of the sheet material 60 is preferably 5 to 30 g / m <2>, more preferably 10 to 20 g / m <2>.

  As the sheet material 60 for forming a three-dimensional gather, a sheet material containing the water-absorbing polymer 10 can be used. That is, the three-dimensional gather may contain the water-absorbing polymer 10. The sheet material forming the three-dimensional gathering contains the water-absorbing polymer 10 having excellent water absorption speed and liquid permeability, so that it is contained in the inside in addition to the physical liquid flow preventing function by the three-dimensional gather. As a result, an excellent liquid absorption capacity and liquid diffusion capacity due to the action of the water-absorbing polymer 10 are expressed, so that the inconvenience that excreted body fluid such as urine leaks outside the three-dimensional gather can be more effectively prevented. . Particularly preferred as the water-absorbing polymer 10 to be included in the sheet material 60 is the above-described water-absorbing polymer having the polyamino acid as a main chain, and in particular, a water-absorbing polymer composed of crosslinked polyglutamic acid.

  As a method of including the water-absorbing polymer 10 in the sheet material 60 for forming a three-dimensional gather, for example, a method of laminating the sheet material 60 in multiple layers and sandwiching the water-absorbing polymer between the adjacent sheet materials 60 and 60 can be considered. . In addition, a method of fixing a water-absorbing polymer with a water-soluble binder such as hot melt or acrylic emulsion or water or CMC on the inner surface of the diaper in the three-dimensional gather; And a method of fixing the water-absorbing polymer in each room. The content (distribution amount) of the water-absorbing polymer 10 in the sheet material 60 is preferably 5 to 100 g / m <2>, more preferably 10 to 50 g / m <2>, from the viewpoint of instantly solidifying the liquid. In order to prevent the elastic member from expanding and contracting due to the swelling of the water-absorbing polymer, it is preferable to separate the elastic member and the water-absorbing polymer as the position where the water-absorbing polymer is included. In order not to get over, it is preferable that a water-absorbing polymer is present near the base of the three-dimensional gather, and in order to prevent back and front leakage, the water-absorbing polymer is included up to the tip in the longitudinal direction of the three-dimensional gather, and the tip Is preferably sealed with hot melt or the like.

As the surface sheet 2, various types conventionally used in this type of diaper can be used, and there is no limitation as long as it can permeate liquid such as urine. For example, synthetic fiber or natural fiber And woven fabrics, nonwoven fabrics, and porous sheets. As an example of the surface sheet 2, a core-sheath structure type (including side-by-side type) composite fiber using polypropylene or polyester as a core component and polyethylene as a sheath component is formed into a web by carding and then nonwoven fabric by an air-through method (predetermined thereafter) And may be subjected to hole opening treatment). From the viewpoint of high liquid permeability (dry feeling), an apertured sheet made of polyolefin such as low density polyethylene can also be preferably used.
As the back sheet 4, various types conventionally used in this type of diaper can be used, and liquid-impermeable or water-repellent and moisture-permeable ones are preferably used. As the back sheet 4, for example, a sheet that can be used as the above-described sheet material 60 for forming a three-dimensional gather can be used. Further, the width of the back sheet 4 is set to be approximately the same as the width of the absorbent body and is arranged on the non-skin contact surface side of the absorbent body. You may provide a laminated body etc. with a film as a sheet | seat which comprises the external shape of a diaper.
The non-skin contact surface is a surface that is directed toward the clothing side (the side opposite to the wearer's skin side) when the diaper is worn. Hereinafter, the term skin contact surface may be used, and the skin contact surface is a surface directed toward the wearer's skin when the diaper is worn.

  The diaper 1 of 1st Embodiment can be used similarly to a normal expansion | deployment type diaper. This diaper 1 has a high water absorption rate for body fluids such as urine and is excellent in liquid permeability due to the action of the water-absorbing polymer 10 contained in the absorbent body 3. It can absorb quickly (spot absorption) without spreading unnecessarily in the direction, hardly cause gel blocking, and hardly cause liquid leakage. Further, the water-absorbing polymer 10 has various functions of pulp fibers usually used in this type of absorber, such as a temporary stock ability of liquid, liquid diffusion ability, and pressure relaxation ability. It is possible to design the distribution amount of the water-absorbing polymer 10 at a high concentration, and it is possible to reduce the amount of pulp fibers used in the absorbent body and to make the absorbent body thinner. The absorbent body 3 in the diaper 1 of the first embodiment takes advantage of the characteristics of the water-absorbing polymer 10 and embodies reduction of the amount of pulp fiber used and thinning of the absorbent body.

  Hereinafter, other embodiments (second to ninth embodiments) of the present invention will be described. Regarding other embodiments to be described later, components that are different from the diaper 1 of the first embodiment described above will be mainly described, and similar components will be denoted by the same reference numerals and description thereof will be omitted. The description about the diaper 1 of 1st Embodiment is applied suitably to the component which is not demonstrated in particular.

  FIG. 3 is a diagram showing a second embodiment of the present invention. The disposable diaper 1 of 2nd Embodiment differs in the structure of the absorber 3 from 1st Embodiment. The absorbent body 3 of the second embodiment is composed of a fiber mixture 33 of the water-absorbing polymer 10 and a fibrous material. The configuration of the fiber mixture 33 itself is the same as that of a conventionally known absorber. The entire fiber mixture 33 (absorber 3) or a portion excluding both end faces in the longitudinal direction is covered with a covering sheet (not shown). The covering sheet is for keeping the shape-retaining property of the mixture 33 and preventing the water-absorbing polymer 10 from falling off, and is made of a liquid-permeable sheet. As the covering sheet, for example, paper such as tissue paper, various non-woven fabrics, perforated films and the like can be used.

  In 2nd Embodiment, as a fibrous material used together with the water absorbing polymer 10 as a structural component of the fiber mixture 33, what is normally used in the said technical field can be used suitably. As the fiber mixture 33, for example, a fibrous material and a water-absorbing polymer are uniformly mixed in air and molded into a specific shape, or a water-absorbing polymer is sprayed on a web to form a mixed state, or a long Examples include those obtained by spreading fibers and spraying and mixing a water-absorbing polymer, and those obtained by laminating. Examples of the fibrous material include natural fibers such as wood pulp, plant pulp, cotton, wool, and hemp, recycled fibers such as rayon and acetate, and single or composite fibers such as polypropylene, polyethylene, polyethylene terephthalate, and nylon. 1 type of these can be used individually or in mixture of 2 or more types. As the fibrous material, it is possible to use an irregular cross-section fiber having a circular or Y-shaped, C-shaped or hollow cross section. As the fibrous material, either one having hydrophilicity or hydrophobicity may be used. The fineness and fiber length of the fibrous material are not particularly limited, but the fineness of the recycled fiber or synthetic fiber is preferably 1.7 to 10 dtex, more preferably 2.1 to 7.8 dtex, and the fiber length is preferably Is 3 mm or more, more preferably 5 mm or more. However, this does not apply to natural fibers.

  In the second embodiment, the content ratio of the water-absorbing polymer 10 and the fibrous material in the fiber mixture 33 is preferably (weight-absorbing polymer / fibrous material) = 5/1 to 1/3 by weight. / 1-1 / 1 is more preferable. Normally, the content weight ratio of the water-absorbing polymer to the fibrous material in this type of absorbent body (fiber mixture) is (water-absorbing polymer / fibrous material) = 1 or less, and the content weight ratio is 1 The above absorbent body is an absorbent body having a so-called pulpress structure in which the ratio of the fibrous material is small. Such a pulpress structure can reduce the bulk by reducing the amount of the fibrous material used, so that the absorber can be thinned and is effective in improving the feeling of wearing the absorbent article. In 2nd Embodiment, the usage-amount of a fibrous material can be reduced by using the water absorbing polymer 10 excellent in the various characteristics mentioned above, and it can be set as the absorber of a thin pal press structure.

The thickness and basis weight of the fiber mixture 33 (absorber 3) in the second embodiment can be adjusted according to the use of the fiber mixture 33. For example, when used as an absorbent body for disposable diapers for infants, the thickness is preferably 0.5 to 5.0 mm, more preferably 1.0 to 3.0 mm, and the basis weight is preferably 100 to 800 g / m ^2, still more preferably 200-500 g / m ^2. When used as an absorbent body for adult disposable diapers, it is preferably 0.5 to 10 mm, more preferably 1.0 to 8.0 mm, and the basis weight is preferably 100 to 1000 g / m ² , more preferably. Is 300 to 700 g / m ² . Moreover, although the fiber mixture 33 is an absorber of the disposable diaper 1, it can also be used as an absorbent body of a sanitary napkin, and when used as an absorbent body of a sanitary napkin, the thickness is preferably 0.00. 5～5.0Mm, more preferably from 1.0 to 3.0 mm, basis weight is preferably 50 to 500 g / m ^2, more preferably a 100 to 400 g / m ^2.

As a particularly preferable form of the fiber mixture 33 (absorber 3) in the second embodiment, the following forms (1) and (2) may be mentioned.
(1) It includes a water-absorbing polymer 10 and a fibrous material of a long fiber having a fiber length of 70 mm or more, preferably 80 mm or more, and the content weight ratio thereof is (water-absorbing polymer / fibrous material) = 1 or more, preferably A fiber mixture (absorber) that is 3 or more.
(2) A fiber mixture (absorber) obtained by mixing the water-absorbing polymer 10 and the fibrous material placed in the airflow by dropping and depositing them on the net (airlaid method), and the content ratio of the two However, (water absorbent polymer / fibrous material) = 1 or more, preferably 4 or more.

  Examples of the long fiber fibrous material used in the fiber mixture (absorber) of (1) include long fibers of acetate, rayon, and various synthetic fibers. Examples of acetate include cellulose triacetate and cellulose diacetate. As the synthetic fiber, for example, a single fiber such as polyethylene, polypropylene, polyethylene terephthalate, nylon or the like, or a composite fiber containing two or more of these resins with a surface treatment with a surfactant is used.

  In the fiber mixture (absorber) of (1), the water-absorbing polymer 10 is embedded and supported in an aggregate (web) of long-fiber fibrous materials. That is, the water-absorbing polymer 10 enters the space of the aggregate formed by the fibrous material of long fibers contained in the fiber mixture, and even if external stress is applied to the fiber mixture, Therefore, it is difficult to move and drop off and is carried on the aggregate. In the loaded state of the water-absorbing polymer 10, the fibrous material of long fibers is entangled with or caught by the water-absorbing polymer 10, or the water-absorbing polymer 10 adheres to the fibrous material due to its own stickiness. However, the fibrous material and the water absorbent polymer 10 are not chemically bonded, and the water absorbent polymer 10 is not fixed to the fibrous material.

  The fiber mixture (absorber) of (1) can fix the water-absorbing polymer 10 with long fibers and can secure a space for the water-absorbing polymer 10 to swell, and has a high water absorption speed, and can pass through the liquid. The water-absorbing polymer 10 having high properties can maintain or improve the liquid retention speed and liquid permeability without using pulp.

  Examples of the fibrous material used in the fiber mixture (absorber) of (2) include natural fibers such as wood pulp, plant pulp, cotton, wool and hemp, regenerated fibers such as rayon and acetate, polypropylene and polyethylene. , Polyethylene terephthalate, nylon and the like alone or composite fiber, and the like. These can be used alone or in admixture of two or more.

  The fiber mixture (absorber) of (2) is a fiber-like material such as pulp having high capillary force and liquid drawing ability, and quickly transfers the liquid to the water-absorbing polymer 10, and the liquid is absorbed by the water-absorbing polymer 10 having a high water absorption speed. Because it can be absorbed and held quickly, the time for body fluids to touch the skin is extremely short, and rashes can be prevented. Further, as can be seen from the fact that the water-absorbing polymer 10 has a high liquid flow rate under pressure as described above, the amount of the fibrous material used can be reduced more than usual because it is strong against pressure. Can be made thinner.

  According to the second embodiment having the configuration as described above, the same effects as those of the first embodiment can be obtained. In particular, in the second embodiment, since a void is formed between the fibrous material and the water-absorbing polymer or between the water-absorbing polymers, the absorption speed is faster and the absorption capacity is improved. Further, since the water-absorbing polymer is firmly fixed between the fibrous materials, the absorbent body is not easily broken.

  4 to 16 are views showing third to eighth embodiments of the present invention. The disposable diaper 1 of 3rd-8th embodiment differs from 2nd Embodiment only by the point of the structure of the fiber mixture 33 (absorber 3). In the third to eighth embodiments, components that are different from the diaper 1 of the second embodiment described above will be mainly described, and similar components will be denoted by the same reference numerals and description thereof will be omitted. The description about the diaper 1 of 2nd Embodiment is applied suitably to the component which is not demonstrated especially.

  4 and 5 are views showing a third embodiment of the present invention. In 3rd Embodiment, the high basic weight by which the water absorbing polymer 10 is distribute | arranged by the excretion point of the fiber mixture 33 (absorber 3) compared with the other site | part of this fiber mixture 33 with high basic weight. Region 11 is formed. Other regions other than the high basis weight region 11 in the fiber mixture 33 of the third embodiment are the low basis weight region 12 in which the water-absorbing polymer 10 is arranged at a lower basis weight than the high basis weight region 11. It has become. As shown in FIG. 5, both the high basis weight region 11 and the low basis weight region 12 are continuously arranged in the thickness direction of the fiber mixture 33. An excretion point is a site | part in which a wearer's excretion part is located at the time of wear of a diaper, and exists in the site | part which extends from the front side (abdominal side) to the back side (back side) a little from the center part of a diaper longitudinal direction. The excretion points are not always fixed at a certain point, but differ depending on the sex of the diaper wearer, the type of excrement (urine or stool), or the posture at the time of excretion due to age or age. Therefore, the high basic weight area | region 11 formed in the excretion point of the absorber 3 is suitably changed according to the use etc. of a diaper.

In 3rd Embodiment, the distribution amount of the water absorbing polymer 10 in the high basic weight area | region 11 becomes like this. Preferably it is 150 g / m < ² > or more, More preferably, it is 150-400 g / m < ² >.
Further, the distribution amount of the water-absorbing polymer 10 in the low basis weight region 12 is preferably 150 g / m ² or less, still more preferably from 50 to 150 g / m ^2.
Moreover, the distribution amount difference of the water-absorbing polymer 10 between the high basis weight region 11 and the low basis weight region 12 is preferably 50 to 150 g / m ² , more preferably 50 to 100 g / m ² .

  In addition, a certain product (absorbent article), as in the third embodiment, “the excretion point of the absorbent body is arranged with a high basis weight of the water-absorbing polymer compared to other parts of the absorbent body. It can be confirmed by the following method. That is, the absorbent body is taken out from the product, the absorbent body is divided into three equal parts in parallel to the width direction (usually the same as the width direction of the product), and the centrifugal retention amount of the water-absorbing polymer in each of the three parts is divided. When the maximum value of the difference between these centrifugal retention amounts is greater than or equal to the reference value measured by the above-mentioned method, the product is “the excretion point of the absorber is water absorption compared to other parts of the absorber. ”Is a polymer having a high basis weight. The reference value varies depending on the product, and is 3 g for disposable diapers for infants, 2 g for sanitary napkins, and 5 g for disposable diapers for adults. The reference value is an average value of the reference values obtained in the above manner for each of five or more products.

In addition, 3rd Embodiment is a disposable diaper, The numerical range of the distribution amount of said water absorbing polymer 10 is a thing when the fiber mixture 33 (absorber 3) is used as an absorber of a diaper. When the fiber mixture 33 which concerns on 3rd Embodiment is used as an absorber in other absorbent articles other than a diaper, said preferable distribution amount can be suitably adjusted according to the use of the said absorbent article. For example, when the fiber mixture 33 according to the third embodiment is used as an absorbent body of an absorbent pad (urine collecting pad), the distribution amount of the water absorbent polymer 10 in the high basis weight region 11 of the absorbent pad is preferably 150 g. / M ² or more, more preferably 200 to 400 g / m ² .

  In the third embodiment, the high basis weight region 11 may be formed including only the water-absorbing polymer 10 (without including the fibrous material), or including the water-absorbing polymer 10 and the fibrous material. May be. When the high basis weight region 11 is formed to include the water absorbent polymer 10 and the fibrous material, the content ratio of the water absorbent polymer 10 and the fibrous material in the high basis weight region 11 is a weight ratio, and is an adult. In the case of diapers, (water-absorbing polymer / fibrous material) = 3/1 to 1/2 is preferable, and 2/1 to 1/2 is more preferable. In the case of baby diapers, (water-absorbing polymer / fibrous material) = 5/1 to 1.5 / 1 is preferable, and 3/1 to 1/1 is more preferable.

In 3rd Embodiment, the cross-sectional area of the horizontal cross section of the high basic weight area | region 11 can be adjusted according to the use of the fiber mixture 33 (absorbent body 3). For example, when used as an absorbent body for disposable diapers for infants, 1 to 100 cm ² is preferable, and when used as an absorbent body for disposable diapers for adults, ²⁰ to 400 cm ² is preferable. Moreover, although the fiber mixture 33 is an absorber of the disposable diaper 1, it can be used also as an absorber of a sanitary napkin, and when using as an absorber of a sanitary napkin, 1-30 cm < ² > is preferable.
Further, the shape of the high basis weight region 11 in a plan view of the fiber mixture 33 is not limited to the elliptical shape as shown in FIG. 4, but is a polygon such as a circle, a rectangle, or a square, or an aggregate or stripe thereof. Shape, check shape, etc. may be used.

  In 3rd Embodiment, the low basic weight area | region 12 may be formed including only the fibrous material (not including the water absorbent polymer 10), and formed including the water absorbent polymer 10 and the fibrous material. May be. When the low basis weight region 12 is formed including the water absorbent polymer 10 and the fibrous material, the content ratio of the water absorbent polymer 10 and the fibrous material in the low basic weight region 12 is an adult weight ratio. In the case of disposable diapers, (water absorbent polymer / fibrous material) = 1/2 to 1/5 is preferable, and 1/3 to 1/5 is more preferable. In the case of baby diapers, (water-absorbing polymer / fibrous material) = 1/1 to 1/5 is preferable, and 1/1 to 1/3 is more preferable.

  According to the third embodiment having the configuration as described above, the same effects as those of the second embodiment can be obtained. In particular, in the third embodiment, there is a high basis weight of the water-absorbing polymer 10 in the vicinity of the excretion part (excretion point), and the water-absorbing polymer 10 has a high water absorption rate, so that it can be absorbed quickly without spreading body fluid ( Spot absorption). Furthermore, since the water-absorbing polymer 10 is also excellent in liquid permeability, gel blocking due to the swollen water-absorbing polymer 10 in the vicinity of the excretion portion is unlikely to occur during the second and subsequent excretion, and the liquid is quickly passed through and absorbed. The liquid can be spread to unabsorbed parts of the body.

  6-8 is a figure which shows 4th Embodiment of this invention. 4th Embodiment differs in arrangement | positioning of the high basic weight area | region 11 and the low basic weight area | region 12 compared with 3rd Embodiment. In 4th Embodiment, the other than except the said excretion point of this fiber mixture 33 in the peripheral part (refer FIG. 6) of the fiber mixture 33 or the longitudinal direction both sides (refer FIG. 7) of the fiber mixture 33 A high basis weight region 11 in which the water-absorbing polymer 10 is arranged with a high basis weight as compared with the portion is formed. Another region in the fiber mixture 33 of the fourth embodiment is a low basis weight region 12. The width of the peripheral edge portion and both longitudinal sides of the fiber mixture 33 in the fourth embodiment, that is, the width of the high basis weight region 11 is preferably 10 to 50 mm, and more preferably 10 to 30 mm. In addition, the basis weight of a water absorbing polymer may be the same as the peripheral part or the longitudinal direction both sides of an absorber, and the said excretion point, and whichever may be high.

In 4th Embodiment, the distribution amount of the water absorbing polymer 10 in the high basic weight area | region 11 becomes like this. Preferably it is 100 g / m < ² > or more, More preferably, it is 100-400 g / m < ² >.
Further, the distribution amount of the water-absorbing polymer 10 in the low basis weight region 12 is preferably 100 g / m ² or less, still more preferably from 50 to 100 g / m ^2.
Moreover, the distribution amount difference of the water absorbent polymer 10 between the high basis weight region 11 and the low basis weight region 12 is preferably 50 to 200 g / m ² , more preferably 50 to 100 g / m ² .

  In addition, a certain product (absorbent article) is a water-absorbing polymer as in the fourth embodiment, in which “the peripheral edge portion or both longitudinal side portions of the absorbent body are compared with other portions excluding the excretion point of the absorbent body”. Can be confirmed by the following method. That is, after the absorber is taken out from the product, the entire absorber is sufficiently swollen with physiological saline (0.9 wt% sodium chloride water using ion-exchanged water), and 1) the peripheral portion of the absorber Measure the thickness under no load at any five or more locations (or both sides in the longitudinal direction), and 2) any five or more locations other than the portion corresponding to the excretion point of the absorber. , When the difference between the thickness of 1) (average value of a plurality of thickness measurement values) and the thickness of 2) (average value of the plurality of thickness measurement values) is 0.5 mm or more, the product The absorbent body has a high basis weight compared to other parts excluding the excretion point of the absorbent body at the peripheral edge or both longitudinal sides of the absorbent body "

In addition, 4th Embodiment is a disposable diaper, The numerical range of distribution amount of said water absorbing polymer 10 is a thing when the fiber mixture 33 (absorber 3) is used as an absorber of a diaper. When the fiber mixture 33 which concerns on 4th Embodiment is used as an absorber in other absorbent articles other than a diaper, said preferable distribution amount can be suitably adjusted according to the use of the said absorbent article. For example, when the fiber mixture 33 according to the fourth embodiment is used as an absorbent body of an absorbent pad (urine collecting pad), the distribution amount of the water absorbent polymer 10 in the high basis weight region 11 of the absorbent pad is preferably 150 g. / M ² or more, more preferably 150 to 300 g / m ² .

  According to the fourth embodiment having the configuration as described above, the same effects as those of the second embodiment can be obtained. In particular, in the fourth embodiment, the water-absorbing polymer 10 is distributed at a high concentration on the peripheral edge portion or both longitudinal sides of the fiber mixture 33 (absorbent body 3). Can be prevented. As in the fourth embodiment, the liquid pool can be prevented from rising up above the absorbent body (fiber mixture 33) shown in FIGS. 6 to 8 and the side edge in the width direction of the absorbent body. By using together with gathers, it becomes more effective.

  9 and 10 are diagrams showing a fifth embodiment of the present invention. 5th Embodiment is the form which combined the characteristic part of 3rd Embodiment and 4th Embodiment (form shown in FIG. 7). That is, in the fifth embodiment, the water absorbent polymer 10 is disposed at a high basis weight on the excretion point and both longitudinal sides of the fiber mixture 33 as compared with other parts of the fiber mixture 33. A basis weight region 11 is formed. Another region in the fiber mixture 33 of the fifth embodiment is a low basis weight region 12.

  According to the fifth embodiment having the above-described configuration, the same effects as those of the second embodiment are achieved. In particular, in the fifth embodiment, since the water-absorbing polymer 10 is distributed at a high concentration on the excretion point of the fiber mixture (absorber 3) and on both sides in the longitudinal direction, the spot absorption of the liquid is particularly excellent. Lateral leakage can be effectively prevented.

  11 and 12 are views showing a sixth embodiment of the present invention. In the sixth embodiment, the fiber mixture 33 (absorber 3) includes a high basis weight region 11 in which the water absorbent polymer 10 is arranged at a high basis weight, and the water absorbent polymer 10 in the high basis weight region 11. A low basis weight region 12 arranged at a lower basis weight than the high basis weight region 11 and the low basis weight region 12 in the longitudinal direction L and the width direction S of the fiber mixture 33. Alternatingly arranged. Further, each of the high basis weight region 11 and the low basis weight region 12 is continuously arranged in the thickness direction of the fiber mixture 33. In the sixth embodiment, the peripheral portion of the fiber mixture 33 is the high basis weight region 11.

  13 and 14 are views showing a seventh embodiment of the present invention. In the seventh embodiment, the high basis weight region 11 and the low basis weight region 12 are alternately arranged in the longitudinal direction L of the fiber mixture 33 (not arranged alternately in the width direction S). Different from the sixth embodiment.

  15 and 16 are views showing an eighth embodiment of the present invention. In the eighth embodiment, the high basis weight region 11 and the low basis weight region 12 are alternately arranged in the width direction S of the fiber mixture 33 (not alternately arranged in the longitudinal direction L). Different from the sixth embodiment.

In the first 6-8 embodiment, the distribution amount of the water-absorbing polymer 10 in the high basis weight region 11 is preferably 150 g / m ² or more, more preferably from 150 and 400 / m ^2.
Further, the distribution amount of the water-absorbing polymer 10 in the low basis weight region 12 is preferably 150 g / m ² or less, still more preferably from 50 to 150 g / m ^2.
Moreover, the distribution amount difference of the water-absorbing polymer 10 between the high basis weight region 11 and the low basis weight region 12 is preferably 50 to 150 g / m ² , more preferably 50 to 100 g / m ² .

In addition, 6th-8th embodiment is a disposable diaper, and the numerical range of the distribution amount of said water absorbing polymer 10 is a thing when the fiber mixture 33 (absorber 3) is used as an absorber of a diaper. . When the fiber mixture 33 which concerns on 6th-8th embodiment is used as an absorber in other absorbent articles other than a diaper, said preferable distribution amount can be suitably adjusted according to the use of the said absorbent article. it can. For example, when the fiber mixture 33 according to the sixth to eighth embodiments is used as an absorbent body of an absorbent pad (urine collecting pad), the distribution amount of the water absorbent polymer 10 in the high basis weight region 11 of the absorbent pad is preferably Is 150 g / m ² or more, more preferably 150 to 300 g / m ² , and the distribution amount of the water-absorbing polymer 10 in the low basis weight region 12 is preferably 150 g / m ² or less, more preferably 50 to 150 g / m ^{2. 2} .

  The same effects as those of the second embodiment can be obtained by the sixth to eighth embodiments having the above-described configuration. In particular, in the sixth to eighth embodiments, the high basis weight regions 11 and the low basis weight regions 12 are alternately arranged in the longitudinal direction L and / or the width direction S of the fiber mixture 33 (absorbent body 3). Therefore, the liquid can be quickly absorbed and diffused in the high basis weight region 11, and the liquid can be retained to some extent in the low basis weight region 12, so that the water absorbent polymer 10 and the fibrous material can absorb the liquid firmly. After liquid absorption, the water-absorbing polymer 10 swells to form a concavo-convex structure in which the high basis weight region 11 is a convex portion on the surface of the fiber mixture 33 (absorbent body 3). Relieve applied pressure. Moreover, since the concave-convex structure plays a role of a liquid passage by forming the concave-convex structure on the surface of the fiber mixture 33, the liquid can be diffused. Moreover, the uneven structure by the swollen water-absorbing polymer 10 reduces the contact area with the skin and is excellent in terms of air permeability.

The fiber mixture 33 (absorbent body 3) of the third to eighth embodiments described above has a high basis weight region 11 in which the water absorbent polymer 10 is arranged at a high basis weight, and the water absorbent polymer 10 has the high weight. It has the low basic weight area | region 12 distribute | arranged by the low basic weight rather than the basic weight area | region 11, and such a fiber mixture can be manufactured as follows, for example.
For example, when manufacturing an absorber as shown in FIGS. 4 and 5 (absorber in which a high basis weight region is formed at the excretion point of the absorber (central portion of the absorber)), the desired high basis weight region A stacking drum that is configured in the same manner as a known stacking drum except that a concave portion corresponding to the shape and size (area) is formed on the drum surface is preferably used. Specifically, a fiber mixture precursor (fiber web) produced according to a conventional method was conveyed in one direction, and the fiber stacking drum was rotated in the circumferential direction and brought into contact with the precursor being conveyed. In the state, the absorbent polymer and the fibrous material are introduced into the stacking drum in a mixed state, and a high basis weight region having a desired shape and size is formed in the precursor.

  For example, when manufacturing an absorber as shown in FIG. 7 (absorber in which high basis weight regions are formed on both sides in the longitudinal direction of the absorber), a precursor (fiber) of a fiber mixture manufactured according to a conventional method While the web is transported in one direction on the production line, the water-absorbing polymer is dropped from the spouts arranged above the both sides of the precursor. When the width of the spray port (the length in the direction perpendicular to the transport direction of the precursor) is, for example, 10 to 15 mm, the longitudinal direction of the precursor flowing at a constant speed by the water-absorbing polymer sliding down from the spray port The water-absorbing polymer can be sprayed in a width of 10 to 15 mm on both sides. This method is particularly effective when a linear high basis weight region is formed in a plan view of the absorber.

FIG. 17 is a diagram illustrating an example of the ninth embodiment of the present invention. The disposable diaper 1 of 9th Embodiment differs in the structure of the absorber 3 from 1st Embodiment. In the absorbent body 3 of the ninth embodiment, the water absorbent polymer 10 is biased toward the skin contact surface side of the absorbent body 3. That is, in the absorbent body 3 of the ninth embodiment, the water-absorbing polymer 10 is arranged on the skin contact surface side of the absorbent body 3 with a higher basis weight than other parts of the absorbent body 3. . The skin contact surface side here means a region near the skin contact surface of the absorbent body 3 from the central portion in the thickness direction of the absorbent body 3. In the absorbent body 3 of the ninth embodiment, (A) the absorbent body 3 is located on the liquid-retaining pulp layer 34 and the skin contact surface of the pulp layer 34, and is a water absorbent consisting only of the water absorbent polymer 10. And (B) a liquid-retaining pulp layer 34 containing the water-absorbing polymer 10, and the pulp layer 34 has a thickness from the non-skin contact surface side toward the skin contact surface side. And a form having a density gradient in which the distribution amount (basis weight) of the water-absorbing polymer 10 increases in the direction. FIG. 17 shows the form (A). The pulp layer 34 and the water-absorbing polymer layer 35 are integrally covered with a covering sheet (not shown) in its entirety or a portion excluding both end faces in the longitudinal direction.
In the product, the centrifugal retention amount is measured with a red-colored physiological saline, the cross section is image-processed, and the uneven distribution of the water-absorbing polymer is confirmed by the degree of redness.

  Whether a certain product (absorbent article) is “the water-absorbing polymer is biased toward the skin contact surface side of the absorber” as in the ninth embodiment is determined by the following method. Can be confirmed. That is, the absorbent body is taken out from the product, and the entire absorbent body is sufficiently swollen with a physiological saline colored red (0.9% by weight sodium chloride water using ion-exchanged water). The centrifugal retention amount of the water-absorbing polymer is measured by the method described above, and the R / G value indicating the degree of redness is read for the cross-section of the absorber using image processing software, etc. Can be confirmed. When the skin contact surface side of the absorbent body is more reddish than other parts, the product is “the water absorbent polymer is biased toward the skin contact surface side of the absorbent body”. .

  The pulp layer 34 is basically formed only from pulp fibers, but may contain materials other than pulp fibers. Examples of components other than pulp fibers that can be contained in the pulp layer 34 include hydrophilic fibers such as rayon, and other synthetic fibers. Further, the pulp layer 34 may contain a water-absorbing polymer, and the water-absorbing polymer may be the above-described water-absorbing polymer (water-absorbing polymer 10) according to the present invention. Other water-absorbing polymers (for example, conventionally known water-absorbing polymers such as sodium polyacrylate described above) may be used. Among these, it is particularly preferable to use the water-absorbing polymer 10 according to the present invention because the water-absorbing speed is fast, so that the body fluid is drawn more quickly, and the sticking away from the skin is suppressed.

  The thickness of the pulp layer 34 can be adjusted according to the use of the absorber 3. For example, when used as an absorbent body for disposable diapers for infants, the thickness is preferably 0.5 to 5.0 mm, more preferably 1.0 to 3.0 mm. When used as an absorbent body for adult disposable diapers, the thickness is preferably 0.5 to 10 mm, more preferably 1.0 to 9.0 mm. Moreover, although the absorber 3 of 9th Embodiment is an absorber of the disposable diaper 1, it can be used also as an absorber of a sanitary napkin, When using as an absorber of a sanitary napkin, Preferably it is 0. .5 to 5.0 mm, more preferably 1.0 to 4.0 mm.

The water absorbent polymer layer 35 is formed by spraying a large number of particulate (spherical) water absorbent polymers 10. A large number of water-absorbing polymers 10 are uniformly distributed over the entire skin contact surface side of the absorbent layer 34. The thickness of the water absorbent polymer layer 35 is preferably 0.1 to 3.0 mm, more preferably 0.5 to 1.5 mm, and the basis weight (distribution amount of the water absorbent polymer 10) is preferably 50 to 500 g. / M ² , more preferably 100 to 300 g / m ² . The water-absorbing polymer layer 35 is an aggregate of a large number of particulate water-absorbing polymers 10, and the water-absorbing polymers 10 are adhered to each other due to the adhesiveness of the polymer itself. The water absorbent polymer layer 35 does not contain a binder for binding a large number of water absorbent polymers 10.

  According to the ninth embodiment having the above-described configuration, the same effect as that of the first embodiment can be obtained. In particular, in the ninth embodiment shown in FIG. 17, the pulp layer 34 is made of only the water-absorbing polymer 10 adjacent to the pulp layer 34 and having an excellent liquid holding capacity as compared with pulp fibers. Since the water-absorbing polymer layer 35 is formed, liquid return (a phenomenon in which the liquid absorbed by the absorber returns to the topsheet side) can be effectively suppressed. Further, since the water-absorbing polymer 10 is excellent in liquid permeability as described above, even if the water-absorbing polymer 10 is arranged in the uppermost layer of the absorbent body 3 as described above, there is no possibility of causing gel blocking, and the liquid pool Can be effectively suppressed.

As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment.
For example, in the above-described embodiment, an unfolded disposable diaper is given as one application example of the absorbent article of the present invention. For example, a pants-type disposable diaper, a sanitary napkin, a panty liner, an incontinence liner, an absorbent pad (urine) It can also be applied to a pad).

In the ninth embodiment, the water-absorbing polymer layer 35 is formed on the entire surface of the absorbent layer 34 on the skin contact surface side, but above the peripheral portion of the absorbent layer 34 (the skin contact surface side of the peripheral portion). It may be formed only on the upper side, or may be formed only above each side in the longitudinal direction of the absorbent layer 34 (on the skin contact surface side of each side in the longitudinal direction). According to these embodiments, it is possible to effectively prevent liquid accumulation, and furthermore, due to the presence of the three-dimensional gather, liquid accumulation is further effectively prevented.
All the parts of only the one embodiment described above can be used together as appropriate.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these.

(Water-absorbing polymer A)
Water-absorbing polymer A was produced by the following procedure. An aqueous solution of an azo initiator and an epoxy crosslinking agent (polyglycerol polyglycidyl ether, manufactured by Nagase Kasei Co., Ltd., trade name “Denacol EX-810”) is added to acrylic acid neutralized with an aqueous sodium hydroxide solution. A homogeneous solution was obtained to obtain a monomer / initiator aqueous solution. The obtained solution was dropped into a separately prepared dispersant / organic solvent / water mixture with heating and stirring. After completion of the dropwise addition, heating and stirring were further continued. After completion of the polymerization, the product was fractionated and dried under reduced pressure to obtain irregularly-shaped granular gel partially crosslinked acrylic acid (sodium) polymer particles. The polymer particles are adjusted to a predetermined moisture content, subjected to additional crosslinking in the presence of Denacol EX-810, and dried to obtain a water-absorbing polymer. Adjusting the water absorption speed, liquid flow rate under pressure, centrifugal retention, and saturated water absorption by vortex method for water-absorbing polymer, adjust the reaction temperature, dripping time, heating / stirring time after completion of dripping, degree of post-crosslinking, etc. This can be done. Finally, 0.5% by weight of Aerosil (synthetic silica, manufactured by Nippon Aerosil Co., Ltd., Aerosil 200) is added to the obtained water-absorbing polymer and mixed well. The obtained water-absorbing polymer was classified with a standard sieve manufactured by Tokyo Screen Co., Ltd. specified in JIS Z 8801, to obtain a water-absorbing polymer A having an average particle size of 200 μm.

(Water-absorbing polymer B)
Meiji Food Materia Co., Ltd., acid-type polyglutamic acid (PGA) by precipitation recovery of Na salt-type polyglutamic acid (PGA-Na) having a polymerization degree of 1200 (number average molecular weight 180,000, weight average molecular weight 820,000) under acidic conditions -H). 100 parts by weight of PGA-H thus obtained and 28 parts by weight of sodium hydroxide were dissolved in 728 parts by weight of water, and 9.7 parts by weight of Denacol EX-810 (manufactured by Nagase Chemtex Co., Ltd.) was added as a cross-linking agent. After the addition, it was heated at 70 ° C. for 16 hours. Subsequently, after freeze-drying, the mixture was pulverized to a particle size of 850 μm or less with a mixer and further dried at 70 ° C. for 3.5 hours. Thereafter, classification with a sieve was performed to obtain a particulate water-absorbing polymer. By adding 0.5% by weight of Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) to the water-absorbing polymer thus obtained and mixing well, the desired water-absorbing polymer B (polyamino acid) Water-absorbing polymer having a main chain).

(Water-absorbing polymer C)
In the production of the water-absorbing polymer B, a water-absorbing polymer was produced in the same procedure as the production of the water-absorbing polymer B except that the post-crosslinking time was shortened to weaken the crosslinking, and this was designated as a water-absorbing polymer C.

(Water-absorbing polymer D)
A water-absorbing polymer was produced in the same manner as in the production of the water-absorbing polymer B, except that the post-crosslinking time was increased in the production of the water-absorbing polymer B and the crosslinking was strengthened.

(Water-absorbing polymer E)
A commercially available water-absorbing polymer (Sundia Co., Ltd., DS-50TS) made of an acrylic acid polymer was used as the water-absorbing polymer E.

(Water-absorbing polymer F)
A commercially available water-absorbing polymer (Sundia Co., Ltd., SK701) made of an acrylic acid polymer was used as the water-absorbing polymer F.

(Water-absorbing polymer G)
A commercially available water-absorbing polymer (Sundia Co., Ltd., IM930) made of an acrylic acid polymer was used as the water-absorbing polymer G.

  For the water-absorbing polymers A to G, 1) the water absorption rate by the vortex method, 2) the liquid passing rate under pressure at 2.0 kPa, 3) the water absorption amount by the centrifugal dehydration method, and 4) the saturated water absorption amount, respectively. Measured according to the method. These results are shown in Table 1 below.

[Example 1]
Using the water-absorbing polymer A, the absorbent body 3 according to the first embodiment shown in FIG. First, a layer made of fluff pulp (Wearhauser NB416) having a basis weight of 100 g / m ² and a thickness of 0.8 mm is used as the upper and lower layers 30, 31, and 7.0 g of a water-absorbing polymer between the upper layer 30 and the lower layer 31. uniformly sprayed a (distribution amount 115 g / m ² of the water-absorbing polymer a), then with coating the upper surface with a tissue basis weight 16g / m ^2, coating the lower surface with a tissue basis weight 16g / m ² Thus, the absorber 3 having a length of 470 mm and a width of 165 mm was produced.
And the disposable diaper was produced in the following procedure using the absorbent body 3 thus produced as an absorbent body. The top sheet (length 540 mm, width 210 mm) of the relief urine removal pad made by Kao Corporation is used as the top sheet, and the back sheet (length 540 mm, width 210 mm) of the relief urine collection pad made by Kao Corporation as the back sheet. ), The absorbent body 3 produced as described above is placed at the center of the back sheet, the top sheet and the back sheet are joined with an adhesive around the absorbent body 3, and a three-dimensional gather is provided. In addition, a disposable diaper having a rectangular shape in a plan view was produced in the unfolded state as shown in FIG.

[Example 2]
In Example 1, a disposable diaper was produced in the same manner as in Example 1 except that the configuration of the absorber 3 was the same as that in the ninth embodiment shown in FIG. In Example 2, a layer made of fluff pulp (Warehauser NB416) having a basis weight of 200 g / m ² and a thickness of 0.8 mm was used as the pulp layer 34, and 7.0 g of the pulp layer 34 on the skin contact surface. Water-absorbing polymer A is uniformly sprayed (distribution amount of water-absorbing polymer A is 115 g / m ² ), and then the whole is covered with a tissue having a basis weight of 16 g / m ² to prepare absorbent body 3. Used as.

Example 3
In Example 1, a disposable diaper was produced in the same manner as in Example 1 except that the configuration of the absorber 3 was the same as that in the third embodiment shown in FIGS. 4 and 5, and this was used as a sample of Example 3. . In Example 3, the high basis weight region 11 is formed as a vertically long rectangular region of 100 mm × 150 mm in the central portion (near the excretion point) of the absorber 3 in a plan view of the absorber 3 shown in FIG. In addition, the longitudinal direction of the high basis weight region 11 coincides with the longitudinal direction of the absorbent body 3. Moreover, the high basic weight area | region 11 of Example 3 is formed from the water absorbing polymer A and fluff pulp (Warehauser NB416), and the distribution amount of the water absorbing polymer A in this high basic weight area | region 11 is 200 g / m < ² >. The content ratio of the water absorbent polymer A and the pulp in the high basis weight region 11 is (water absorbent polymer A / pulp) = 1/1 by weight ratio. On the other hand, the low basis weight area | region 12 which is area | regions other than the high basic weight area | region 11 in the absorber 3 of Example 3 is formed from the water absorbing polymer A and fluff pulp (Warehouser NB416), and this low basic weight area | region. 12 is 100 g / m ² , and the content ratio of the water-absorbing polymer A and pulp in the low basis weight region 12 is (weight-absorbing polymer A / pulp) = 1 by weight ratio. / 2.

Example 4
A disposable diaper was prepared in the same manner as in Example 1 except that the water-absorbing polymer B was used instead of the water-absorbing polymer A in Example 1, and this was used as a sample of Example 4.

Example 5
A disposable diaper was prepared in the same manner as in Example 2 except that the water-absorbing polymer C was used instead of the water-absorbing polymer A in Example 2, and this was used as a sample of Example 5.

Example 6
A disposable diaper was prepared in the same manner as in Example 3 except that the water-absorbing polymer B was used in place of the water-absorbing polymer A in Example 3, and this was used as the sample of Example 6.

Example 7
A disposable diaper was prepared in the same manner as in Example 1 except that the water-absorbing polymer D was used instead of the water-absorbing polymer A in Example 1, and this was used as a sample of Example 7.

[Comparative Example 1]
A disposable diaper was prepared in the same manner as in Example 1 except that the water-absorbing polymer E was used instead of the water-absorbing polymer A in Example 1, and this was used as a sample of Comparative Example 1.

[Comparative Example 2]
A disposable diaper was prepared in the same manner as in Example 1 except that the water-absorbing polymer F was used instead of the water-absorbing polymer A in Example 1, and this was used as a sample of Comparative Example 2.

[Comparative Example 3]
A disposable diaper was produced in the same manner as in Example 1 except that the water absorbent polymer G was used in place of the water absorbent polymer A in Example 1, and this was used as a sample of Comparative Example 3.

[Evaluation]
About each produced disposable diaper (product), the following methods evaluated the product thickness, the mole value, the surface liquid flow distance, the absorption rate, and the liquid diffusion area. These results are shown in Tables 2 and 3 below. All of these evaluations were performed in an environment of 23 ° C. and 50% RH.

<Evaluation of product thickness>
An acrylic plate having a size of 5 cm × 5 cm is placed on the disposable diaper, a weight is placed on the acrylic plate, and measurement is performed under a load of 2.5 g / cm ² . For the measurement, LK080 class 2 laser displacement meter manufactured by Keyence Corporation was used. The number of measurement points was an average of 5 points, and when the measurement value fluctuated 20% or more, the data was deleted and another measurement value was added. The disposable diaper used for the measurement was in a state where wrinkles were extended by applying a load of 250 g / cm ² in advance for 12 hours in the expanded state.

<Evaluation of surface liquid flow distance and mole value>
A disposable diaper is fixed on a smooth surface of a table with an inclination angle of 45 ° with the top sheet side facing up and the ventral side facing up. Next, with respect to this disposable diaper, 50 g of physiological saline (0.9 wt% saline using ion-exchanged water) colored with red No. 2 in the longitudinal direction 260 mm from the abdominal end and in the center in the width direction. It inject | pours with an injection | pouring speed | rate of 5 g / sec, and measures the longest distance (mm) the physiological saline flowed on the surface sheet immediately after injection | pouring. After being left for 10 minutes after the injection of physiological saline, the same operation as described above is performed, and this operation is repeated until leakage occurs from the end of the diaper. The number obtained by subtracting 1 from the number of injections in which leakage has occurred is defined as the leakage value. The shorter the surface liquid flow distance is, and the higher the mole value indicating the number of times of repeated absorption is, the higher the evaluation is.

<Evaluation of absorption rate>
With the disposable diaper spread in a flat shape, with the topsheet facing up and fixed on a horizontal surface, place an acrylic plate with a cylindrical injection part on the topsheet at the center of the absorbent, and then A weight is placed on the acrylic plate, and a load of 1.6 kPa is applied to the center of the absorber. The injection part provided in the acrylic plate has a cylindrical shape (height 53 mm) with an inner diameter of 36 mm. The acrylic plate has a cylindrical part of the cylindrical injection part at a third portion in the longitudinal direction and the central axis in the width direction. A through hole having an inner diameter of 36 mm is formed so that the central axes coincide with each other and communicates between the inside of the cylindrical injection portion and the surface sheet facing surface of the acrylic plate. Next, an acrylic plate is placed so that the central axis of the cylindrical injection portion coincides with the central portion of the absorber in plan view, and 150 g of physiological saline (0.9 wt% saline using ion-exchanged water) is added. Inject from a cylindrical injection part and absorb in a disposable diaper. The time (seconds) from when the physiological saline reached the surface of the diaper until the entire amount of 150 g was absorbed by the diaper was measured, and this was taken as the absorption time of the liquid under pressure. The amount of physiological saline injected, that is, 150 g, was divided by the absorption time to calculate the absorption rate (g / sec). The larger the absorption rate value, the faster the absorption rate and the higher the evaluation.

<Evaluation of liquid diffusion area>
In a state where the disposable diaper is spread in a flat shape and fixed on a horizontal surface with the surface sheet facing upward, the saline (0.9% by weight using ion-exchanged water) is used for the surface sheet in the center of the absorber. Saline solution (150 g) is injected at an injection rate of 5 g / sec and left for 7 minutes. Thereafter, the outline on the absorber is copied and recorded on a transparent sheet. The obtained image was processed using image analysis processing software (Image-Pro plus, Media Cybernetics) to determine the liquid diffusion area (cm ² ). The smaller the value of this liquid diffusion area, the higher the evaluation.

As shown in Tables 2 and 3, Examples 1 to 6 have larger mole values, shorter surface liquid flow distances, faster absorption rates, and smaller liquid diffusion areas than Comparative Example 1. Moreover, although the comparative example 2 obtained the good result regarding the surface liquid flow distance and the liquid diffusion area, it became a result inferior to Examples 1-6 regarding a mole value and an absorption rate. Therefore, it was confirmed that the disposable diapers of Examples 1 to 6 have higher leakage preventing properties and absorption performance than the disposable diapers of Comparative Examples 1 and 2.
In addition, Examples 4 and 6 using the water-absorbing polymer CB, which is a water-absorbing polymer having a polyamino acid as the main chain, have a particularly small liquid diffusion area value compared to the other examples, and there is an apparent discomfort. It can be seen that the effect of reducing or maintaining the skin in a comfortable state is small, and the contact with the wet surface is small.

It is a top view which partially fractures and shows the skin contact surface side (surface sheet side) in the deployment state of the disposable diaper which is a 1st embodiment of the present invention. It is the expanded sectional view which showed typically the II cross section of FIG. FIG. 3 is a view corresponding to FIG. 2 of a second embodiment of the present invention. It is the top view which showed typically the absorber of 3rd Embodiment of this invention. FIG. 5 is a cross-sectional view schematically showing a cross section taken along line II of FIG. 4. It is the top view which showed typically an example of the absorber of 4th Embodiment of this invention. It is the top view which showed typically the other example of the absorber of 4th Embodiment of this invention. It is sectional drawing which showed typically the II sectional view of FIG.6 and FIG.7. It is the top view which showed typically the absorber of 5th Embodiment of this invention. FIG. 10 is a cross-sectional view schematically showing a cross section taken along line II of FIG. 9. It is the top view which showed typically the absorber of 6th Embodiment of this invention. FIG. 12 is a cross-sectional view schematically showing a cross section taken along line II of FIG. 11. It is the top view which showed typically the absorber of 7th Embodiment of this invention. It is sectional drawing which showed the II-II line cross section of FIG. 13 typically. It is the top view which showed typically the absorber of 8th Embodiment of this invention. It is sectional drawing which showed the II line cross section of FIG. 15 typically. It is FIG. 2 equivalent figure of an example of 9th Embodiment of this invention.

Explanation of symbols

1 disposable diaper (absorbent article)
2 Surface sheet 3 Absorber 30 Upper layer 31 Lower layer 33 Fiber mixture 34 Absorbent layer 35 Water-absorbing polymer layer 4 Back sheet 6, 7 Elastic member 10 Water-absorbing polymer 60 Sheet material 61 for forming three-dimensional gathers Joint (base end)
FT Fastening tape LT Landing tape

Claims (8)

An absorbent article comprising an absorbent body comprising a water-absorbing polymer, wherein the water-absorbing polymer has a water absorption rate by a vortex method of 20 seconds or less, and a liquid passing rate under pressure at 2.0 kPa is 60 ml / min. Ri der above,
The water-absorbing polymer has a polyamino acid as a main chain, and the polymerization degree of the polyamino acid is 1200 to 50,000,
The excretion point of the absorbent body is an absorbent article in which the water-absorbing polymer is arranged with a high basis weight as compared with other parts of the absorbent body .   The absorbent article according to claim 1, wherein the water-absorbing polymer has a water absorption amount of 20 g / g or more by centrifugal dehydration. The absorbent body has an upper layer having liquid permeability and a lower layer disposed on the non-skin contact surface side of the upper layer, and the water-absorbing polymer is sandwiched between the upper layer and the lower layer. The absorbent article according to 1 or 2 . The absorptive article according to any one of claims 1 to 4 in which said absorber has a fiber mixture of said water-absorbing polymer and fibrous material. The peripheral part of the said absorber or the both sides of a longitudinal direction are the said water-absorbing polymer with high basic weight compared with the other site | part except the excretion point of this absorber, The any one of Claims 1-4. the absorbent article according to claim. The absorbent body includes a high basis weight region in which the water-absorbing polymer is disposed at a high basis weight, and a low basis weight region in which the water-absorbing polymer is disposed at a lower basis weight than the high basis weight region. has been provided, the absorption according to any one of claim 1 to 5, and the high basis weight region and the low basis weight regions are disposed alternately in the longitudinal and / or width direction of the absorber Sex goods.   The absorbent article according to claim 1 or 2, wherein the water-absorbing polymer is biased toward the skin contact surface side of the absorber. The absorbent article according to any one of claims 1 to 7 , further comprising a three-dimensional gather that can rise above the absorber, wherein the three-dimensional gather includes the water-absorbing polymer.

Images