JP2016120083A - Absorber and sanitary product comprising absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorber in which absorber for sanitary product is improved to make it thinner.SOLUTION: There is provided an absorber 1 comprising an absorption core 4 comprising highly water absorptive polymer particle 2 and water absorptive fiber 3 and sheet member 5 covering the absorption core. The highly water absorptive polymer particle has a water retainment magnification of 37 g/g or more, DW 5 minutes value as absorption volume when the highly water absorptive polymer particle is immersed in physiological saline solution for 5 minutes is 40 ml/g or more, later stage absorption speed calculated with the time at which absorption volume of the highly water absorptive polymer particle reach 40 ml/g to 50 ml/g is 6 ml/g x minutes or more, weak pressurization SFC as liquid diffusion efficiency under weak pressurization is 5×10ml*seconds, repeat absorption force index defined as water retainment magnification x later stage absorption x weak pressurization SFC x 10is two or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an absorbent body and a sanitary product including the absorbent body.

In recent years, absorbents used in sanitary products such as disposable diapers and sanitary napkins have been used by mixing or laminating water-absorbing fibers such as pulp and superabsorbent polymers (hereinafter referred to as SAP). As the body becomes thinner and further ultrathin, the amount of SAP occupies 50% by mass or more. For this reason, if SAP does not have not only the original liquid storage function but also the liquid transport function that water absorption fibers such as pulp do, it will reduce the absorption performance, especially the repeated absorption performance due to the thinning of the absorber. . In order to maintain repeated absorption performance over a long period of time, even when urine is absorbed, the water-absorbing fibers are moistened, and SAP swells and hydrogels, the excreted urine is continuously taken into the absorbent body, It is necessary to transport the liquid to a portion having an absorption capacity and finally hold it in the SAP. However, it is difficult to improve all of the water absorption performance of SAP, particularly the basic performance, which is a trade-off relationship between water retention magnification, absorption speed, and liquid permeability. Therefore, in order to further improve the water absorption performance of the SAP, the aspect of actual absorption in the disposable diaper is narrowed down, the absorption performance to be traded off is balanced in an optimal state, and the most effective and efficient in the targeted absorption aspect. It is necessary to demonstrate absorption performance. For example, Patent Document 1 discloses an SAP having a centrifugal retention capacity (CRC) of at least 26 g / g and a transport value (TW) of at least 15000 cm ³ s. The transport value (TW) is the product of the liquid diffusion performance (SFC) and the core absorption after 60 minutes (DA ₆₀ ) multiplied by 10 ⁷ .

Special table 2008-517116

  According to the invention disclosed in Patent Document 1, the liquid diffusion performance (SFC) is measured as a liquid permeation amount under a pressure load of 0.3 psi (2.07 kPa) on a hydrogel layer swollen for 60 minutes. Measured. It can be said that SFC shows the liquid permeation performance between the swelled hydrogels in a dense state in the vicinity of the urination opening, but in the actually used paper diaper absorber, 100% of the urine excreted repeatedly is 100%. Rather than passing through a hydrogel layer that has absorbed and swollen nearby and diffusing, the hydrogel layer that has swollen and has reduced absorption capacity flows around the top and bottom and side surfaces and is absorbed in the region where the remaining absorption capacity remains. . In order to acquire and retain such a flow of urine, a liquid acquisition diffusion layer (ADL layer) is used in combination with a liquid retention layer in which SAP is present, and an absorber structure that separates liquid acquisition and liquid retention is the mainstream. It has become. According to Patent Document 1, the core absorption amount (DA60) is measured by measuring the absorption amount of a salt solution that is filled with 70 g of water-absorbing polymer particles with a thickness of 3 cm and flows out of the tube over 60 minutes. The core absorption amount (DA60) is measured as a sufficient amount of hydrogel in a sufficient absorption time, and is an excellent method for evaluating the potential of the absorption amount of the hydrogel, but the diffusion holding force measured at a thickness of 3 cm is as described above. Similar to SFC, it is the absorption performance of a hydrogel placed in a dense state, and can be said to be a performance evaluation based on the premise of an absorber configuration in which a liquid acquisition diffusion layer (ADL layer) is used in combination to separate liquid acquisition and liquid retention.

  However, as in Patent Document 1, in an absorber in which SAP is densely arranged and a high-density liquid holding layer and a bulky liquid acquisition diffusion layer (ADL layer) that effectively temporarily holds the liquid are used in combination, In order to improve the permeability of the hydrogel, the water retention ratio is lowered to reduce the water retention and high fluidity, so that it is used with a high basis weight, and combined with the bulky ADL layer, the thinning effect of the absorber is offset Therefore, there is a problem that thinning does not progress.

  In view of the above, an object of the present invention is to provide an absorbent body that can be thinned by improving the absorbent body of a sanitary product.

  For example, in the case of an absorber used for a paper diaper, in a region where the baby's body pressure is not applied, a relatively large amount of urine is temporarily stored inside and outside the absorber compared to the region where the body pressure is applied. The temporarily stored urine is (a) “absorbed urine outside the absorber” that stays outside the absorber (on the surface material), and (b) momentum excreted in the absorber, depending on the degree of binding with the water-absorbing material. There are continuously three stages of urine: “residual urine in the absorbent body” that has been permeated by water pressure but is not retained, and (c) “urine retained in the absorbent body” retained in hydrophilic fibers and SAP. In the excretion 1 to 2 times, there is little “residual urine outside the absorber” and “residual urine in the absorber” due to the large absorption capacity of pulp and SAP. “Externally retained urine” and “absorbed body urine”, particularly “externally absorbed urine” increase, and the risk of leakage outside the disposable diaper increases due to posture change and absorber deformation. In order to reduce the risk of leaking, it is necessary to minimize “residual urine outside the absorber”. To that end, it is necessary to move “residual urine outside the absorber” to the “residual urine within the absorber” as much as possible. is there. “Residual urine in the absorber” is urine temporarily held in a space formed between the water-absorbing materials in the absorber, and conventionally, a bulky material is disposed between the absorber and the surface material as an ADL layer. However, there is a problem that the absorber becomes thick. Therefore, by optimizing the ability of SAP to absorb water and swell, swollen particle diameter (A), swelling speed (B), and efficiency of swelling (C), the storage space of “residual urine in the absorbent” can be used to swell SAP. It was found that it can be effectively generated around the swollen SAP in the thin absorbent body, and the absorption capacity can be maximized repeatedly.

Specifically, the swollen particle diameter (A) is positively correlated with the water retention magnification. This is because SAP particles are swollen by the urine taken in by the SAP and the hydrogel particle diameter is enlarged. The water retention ratio is measured as a centrifugal retention capacity (CRC). The swelling rate (B) is measured as the water absorption rate of SAP, Demand Wetability (DW). The DW value is measured as the rate at which physiological saline is sucked and absorbed without applying a load, and the amount of physiological saline absorbed per hour is expressed in terms of weight or volume. The DW value is generally represented by a 2-minute value, a 5-minute value, or a 15-minute value as a representative value, but is further measured as a 60-minute value close to a state where the SAP is saturated, and has a positive correlation with the absorption rate. The DW5 value also has a high correlation with the repetitive absorption performance, but the higher correlation is the water absorption rate in the state of hydrogelation to some extent and the late water absorption rate. By having a high water absorption rate in the late stage of absorption, “residual urine in the absorber” is quickly taken into the SAP hydrogel and converted into “retained urine in the absorber”, and the remaining capacity of “externally retained urine” is taken into the absorber in parallel. It is possible to quickly reduce “residual urine outside the absorber”. The later absorption rate of the SAP hydrogel becomes important since the absorption capacity of water-absorbing fibers such as pulp remains little after the absorber has repeatedly absorbed. The late absorption rate of the SAP hydrogel is calculated from the time when the amount of SAP particles absorbed reaches 40 ml / g to 50 ml / g. The efficiency (C) for swelling can be measured as liquid permeability. As the liquid permeability, there are known cases where a hydrogel in which SAP has absorbed and swelled and has reached a saturated state is measured in a non-pressurized state, and a saline flow conductivity (SFC) measured in a pressurized state. However, in order to continuously transport “residual urine in the absorbent” to “retained urine in the absorbent”, there is a correlation with the slightly pressurized SFC measured by the hydrogel absorbed in the slightly pressurized state. I discovered that there is. Liquid transport between SAP hydrogels when the SAP hydrogel is fully saturated is unlikely to occur in the actual absorbent body. Moreover, since the liquid transport between the SAP hydrogels in a pressurized state under a large body pressure is too severe, the contribution ratio of the actual absorbent body of the diaper is not large. The absorption of the absorber most contributes to the liquid transport in a state where the SAP hydrogel swollen to the maximum under pressure corresponding to the body pressure of the baby is decompressed and placed in a slightly pressurized state, that is, at the time of slightly pressurized Liquid permeability (slightly pressurized SFC). As described above, in order for the absorber to continuously and stably absorb repeatedly, the water retention ratio of SAP, the absorption rate (DW 5-minute value, late absorption rate), and liquid permeability (slightly pressurized SFC) are important. . However, these are in a trade-off relationship with each other, and by setting the “repetitive absorbency index” obtained by water retention magnification × late stage absorption rate × absorbability under slight pressure × 10 ³ to 2 or more, “residual urine in the absorber” It has been found that the formation speed of the storage space can be maximized and the repeated absorption performance of the thin absorbent body can be maximized.

The present invention that has solved the above problems is an absorbent body comprising a highly water-absorbing polymer particle, an absorbent core containing a water-absorbing fiber, and a sheet member that encloses the absorbent core. Magnification is 37 g / g or more, DW5 minute value is 40 ml / g or more when the superabsorbent polymer particles are aspirated by contact with physiological saline for 5 minutes with no load, DW value of superabsorbent polymer particles The late absorption rate calculated from the time it takes to reach 50 ml / g from 40 ml / g is 6 ml / g · min or more, and the slightly pressurized SFC that is the liquid diffusion performance under slightly pressurized is 5 × 10 ⁻⁶ · ml · second. As described above, the repetitive absorbency index defined by water retention magnification × late-term absorption rate × slightly pressurized SFC × 10 ³ is 2 or more.

  According to the present invention, an SAP that exhibits a specific absorption behavior and a water-absorbing fiber are combined, and an absorbent body that can be thinned and has excellent repeated absorption performance, and a sanitary article including the absorbent body are provided.

The drawings illustrate specific embodiments of the invention and include selective and preferred embodiments as well as the essential features of the invention.
The partial fracture | rupture perspective view which represents typically the absorber which concerns on this invention. The figure showing the cross-sectional shape of a U-shaped test apparatus.

  The following embodiments relate to the absorbent body of the present invention, and include not only an indispensable structure of the invention but also a selective and preferable structure.

  With reference to FIG. 1, the absorbent body 1 includes an absorbent core 4 including SAP (highly water-absorbing polymer) particles 2, water-absorbing fibers 3, and a sheet member 5 that covers the absorbent core 4. It is preferable that the SAP particles 2 contained in the absorbent body 1 are 50 to 100% by mass, and the water absorbent fibers 3 are 0 to 50% by mass. Cellulose fibers, preferably pulp, can be used for the water absorbent fibers 3. The SAP particles 2 are particles of a crosslinked polyacrylic acid sodium salt, and details of the SAP particles 2 according to the present invention will be described later. A liquid-permeable sheet is used as the sheet member 5 that covers the absorbent core 4, and a liquid-permeable sheet can be arbitrarily combined with the liquid-permeable sheet. That is, the entire absorbent core 4 can be encapsulated with a liquid-permeable sheet alone. Moreover, the absorption core 4 can also be hold | maintained between a liquid-permeable sheet | seat and a liquid-impermeable sheet | seat. In this case, the liquid-permeable sheet is disposed on the skin facing surface side facing the skin of the user of the absorber, and the liquid-impermeable sheet is disposed on the non-skin facing surface side facing the skin facing surface. Examples of water permeable sheets include, but are not limited to, non-woven fabrics, tissue paper, and films having a large number of micropores. Examples of liquid-impervious sheets include, but are not limited to, resin films and water-repellent nonwoven fabrics.

The SAP particles 2 used in the absorber 1 of the present invention satisfy any or all of the following conditions.
(1) The water retention ratio of the SAP particles 2 is 37 g / g or more, preferably 39 g / g or more.
(2) The DW5 value of SAP particles 2 is 40 ml / g or more, preferably 50 ml / g or more, more preferably more than 60 ml / g.
(3) The late absorption rate calculated from the time when the amount of absorption of the SAP particles 2 in the DW method reaches from 40 ml / g to 50 ml / g is 6 ml / g · min, preferably 7 ml / g · min or more, preferably It is 10 ml / g · min or more, preferably 14 ml / g · min or more.
(4) The fine pressure SFC, which is the liquid diffusion performance under slight pressure, is 5 × 10 ⁻⁶ · ml · second or more, preferably 7 × 10 ⁻⁶ · ml · second or more.

  The amount of particles having a particle size of less than 300 μm in the SAP particles 2 is preferably 10% by mass or less, more preferably 9% by mass or less, more preferably 8% by mass or less, more preferably 7% by mass or less, and more. Preferably it is 6 mass% or less. The amount of the SAP particles 2 in the absorbent core 4 is 50 to 100% by mass, preferably 50 to 90% by mass, more preferably 50 to 80% by mass, more preferably 50 to 70% by mass, and more preferably. It is 50-65 mass%. At this time, components other than the SAP particles 2 in the absorbent core 4 are water absorbent fibers. Although there is no restriction | limiting in the upper limit of the particle size of SAP particle | grains 2, Preferably it is 1000 micrometers or less, More preferably, it is 900 micrometers or less, More preferably, it is 800 micrometers or less.

  The SAP particles 2 used in the present invention are not particularly limited as long as the above conditions are satisfied. For example, any one or both of the SAP particles 2 obtained by the following two methods can be used.

  In the first method, in order to satisfy the above conditions, an azo radical polymerization initiator having a small self-crosslinking reaction is used as the radical polymerization initiator in the polymerization crosslinking reaction of the acrylic acid polymer, and chain transfer is initiated during the polymerization reaction. The SAP particles 2 used in the present invention can be obtained by adding and reacting an agent. Specifically, the polymerization method described in Japanese Patent No. 5162634 can be used. Further, the reverse phase suspension polymerization method is desirable from the viewpoint that precise polymerization reaction control and a wide range of particle diameters can be controlled. For example, the polymerization method described in Japanese Patent No. 4969778 can be used. In the present invention, after carrying out reverse-phase suspension polymerization of 2 to 3 stages using a water-soluble azo radical polymerization initiator in the presence of a polyvalent glycidyl compound as an internal crosslinking agent, SAP particles 2 obtained by post-crosslinking with a cross-linking agent and having a higher cross-linking density in the vicinity of the surface than the inside are used. The obtained SAP particles 2 have a high water retention capacity, a high absorption capacity under load, an excellent absorption rate, and a low water-soluble content.

In the second method, the relational expression “Repeated Absorption Index” = Water Retention Ratio × Late Absorption Rate × SFC × 10 ³ under Slight Pressurization is deductively captured, and a water-absorbing polymer having a high pressureless DW (Comparative Example 5). The SAP particles 2 used in the present invention (see Examples 2 and 3) can be obtained by cutting a portion having a small particle diameter in (see). The portion having a small particle size contributes to the absorption rate, but the liquid permeability is lowered, and the repeated absorbency index does not increase. Therefore, by reducing the number of particles with a particle size of less than 300 μm contained in the SAP particles 2, the liquid permeability is improved without lowering the non-pressurized DW, and the “late absorption rate” and “repeated absorption index” are improved. It is possible to make it. Moreover, since the internal cross-linking ratio of the water-absorbing polymer is increased by cutting the small particle diameter portion, the water retention ratio can be improved.

<Measurement of water retention magnification>
For the water retention ratio, 1 gram of SAP particles was weighed in a tea bag, immersed in physiological saline at 25 ° C. for 1 hour, and the amount of absorption was measured. Unless otherwise specified, all measurements in this application are performed in a constant temperature and humidity room at 20 ° C. and 65% RH.

<DW5 minute value measurement>
1.000 g of SAP particles were weighed and dispersed as evenly as possible on a 250 mesh nylon mesh set in a DW measuring device, and the amount of physiological saline absorbed was read. As the initial absorption amount, the amount absorbed in 5 minutes (ml / g) was read and used as the DW 5-minute value. The DW measuring apparatus used for the measurement was Demand Wettability Tester manufactured by Scientific Machine & Supplies Co. LTD, and the 250 mesh nylon mesh was N-NO.250HD manufactured by NBC Industries.

<Late absorption rate>
The relationship between the absorption time and the absorption amount is graphed, and the time T ₄₀ (min) required for 1.000 g of SAP particles to absorb 40 ml of physiological saline and the time T ₅₀ (min) required to absorb 50 ml of saline are shown. Reading T ₅₀ -T ₄₀ = ΔT, 10 / ΔT (ml / g · min) was defined as the late absorption rate.

<Slight pressurization SFC>
For liquid permeability, SFC is well known, but it is measured under load and tends to have a low water retention ratio. On the other hand, liquid permeability in a non-pressurized state measured at the maximum swelling magnification is also known, but since the maximum swelling magnification is not reached in the absorbent body, the correlation with the absorbent performance is low. Therefore, a method for evaluating liquid permeability under slight pressure was devised and used as an evaluation index. The evaluation of the slightly pressurized SFC was performed according to the following procedure.
SAP particles (0.200 g) were weighed out and uniformly dispersed on a mesh of a cylinder having an inner diameter of 26 mm and a 250 mesh nylon mesh stuck on the bottom surface. Next, a piston (mass 30 g) having an outer diameter of 25 mm with a 250 mesh nylon mesh pasted on the bottom surface was inserted into the cylinder. Thereafter, the bottom surface of the cylinder into which the piston was inserted was placed on a spacer having a height of 2 mm set in a petri dish storing physiological saline, and water was absorbed for 30 minutes. Next, the cylinder was removed from the physiological saline, and a 200 g weight was placed on the piston and allowed to stand for 3 minutes. Thereafter, the weight and the piston were removed from the cylinder, the inside of the cylinder was filled with physiological saline, and the amount of liquid permeated for 1 minute was weighed to obtain a liquid passing speed F under a slight load. The slightly pressurized SFC was obtained from the following formula. The thickness L ₀ of the Gel layer was determined by measuring the SAP thickness after swelling with a ruler.

<Evaluation of SAP particle size>
SAP particles were evaluated by sieving SAP particles using a sieve specified in JIS Z 8801 and measuring the mass of the sample remaining on each sieve. The sieve openings used were 850 μm, 710 μm, 600 μm, 500 μm, 355 μm, 300 μm, 250 μm, and 150 μm.

<The absorber 1 used for the measurement and the preparation method of a simple diaper>
(1) Pulp (Weyerhaueser, NB416) slit to 5 cm width was supplied to a pulp crusher (Kamas Cell-mill) and pulverized. Next, an SMS nonwoven fabric made of PP fibers was laid on a wire net affixed on a suction box, and a wooden frame was placed thereon, and the pulverized pulp was fed for a predetermined time T for a predetermined basis weight.
(2) A screw feeder spray tube for supplying SAP particles was inserted between the pulp crusher and the suction box, and the rotation speed and supply time were set so as to obtain a predetermined basis weight during lamination. The SAP was supplied 1/4 × T seconds after the pulp was supplied, and a pulp skin layer containing no SAP was formed. Then, while dispersing SAP for 1/2 × T seconds, the mixture was fed into the air flow of pulverized pulp to form a 1 / 2-thick SAP blend layer of the laminate.
(3) An SMS nonwoven fabric was placed on the pulp / SAP laminate, and was pressed with a hydraulic press machine to a predetermined thickness, and the absorber was cut into a width of 120 mm and a length of 350 mm. After removing the SMS on the upper and lower surfaces of the SAP blend layer, a 16 g / m ² tissue (width 120 mm) coated with a hot melt adhesive in a spiral shape is adhered to the upper surface of the SAP blend layer, and the hot melt is further adhered to the lower surface. A 16 g / m ² tissue (width 150 mm) coated in a spiral shape was adhered. Next, both sides of the tissue having a lower width of 150 mm were folded back by 15 mm so that the width of the absorbent body 1 was 120 mm, and the front and rear ends were cut to a length of 350 mm. The thickness of the obtained absorbent body 1 was 2.4 mm. In this way, the absorbent body 1 having an SAP content of 65% by mass (SAP basis weight 300 g / m ² , pulp basis weight 160 g / m ² ) and an SAP content of 55% by mass (SAP basis weight 280 g / m ² , pulp basis weight) 230 g / m ² ) absorber 1 was prepared.
(4) Finally, a PE film coated with hot melt in a spiral shape is bonded to the upper surface of the absorbent body 1, and a hydrophilic through-air nonwoven fabric coated with a hot melt adhesive in a spiral shape is bonded to the lower surface of the absorbent body 1. And the simple diaper (width 190mm, length 400mm) for repeated absorption performance evaluation was created.

<Evaluation method for repeated absorption performance of absorber (method for measuring U-shaped absorption rate)>
1) The simple diaper for absorptive evaluation was arrange | positioned symmetrically to the U-shaped test apparatus shown in FIG. Note that the U-shaped test apparatus was prepared by bending a hard PVC plate having a width of about 170 mm. In FIG. 2, R is 90 mm, L1 is 230 mm, and L2 is 210 mm. The absorptivity was evaluated by supporting the test apparatus with a jig so that the U-shaped opening faced vertically upward.
2) After injecting 80 ml of artificial urine into the center of the simple diaper, the time (seconds) until the artificial urine on the surface of the simple diaper could not be visually observed was measured and taken as the absorption rate.
3) After leaving for 3 minutes, the artificial urine was diffused and marked.
4) The mixture was further left for 7 minutes, the second artificial urine was injected, and the absorption rate measurement and the diffusion position were marked as in the first time. This operation was repeated until the number of injections reached 4. The time (seconds) until 80 ml of artificial urine injected for the fourth time cannot be visually observed is measured, and this time (second) is used as an index for evaluating the repeated absorption performance of the absorber. "U-shaped absorption rate 4th time".

  Table 1 shows the results of repeated absorption performance evaluation of simple diapers prepared using the SAP particles 2 obtained by the first method described above.

  As shown in Table 1, only the SAP particles of Example 1 having a repetitive absorption index of 2 or more are U-shaped regardless of whether the SAP content in the absorber 1 is 55% by mass or 65% by mass. The fourth absorption rate was 60 seconds or less. This indicates that the ability to rapidly absorb 80 ml of artificial urine is maintained even when the SAP content is increased. Therefore, the absorber 1 can be thinned.

  Table 2 shows the results of repeated absorption performance evaluation of simple diapers prepared using the SAP particles 2 obtained by the second method described above.

  As shown in Table 2, the amount of particles having a particle diameter of less than 300 μm contained in the SAP particles 2 is 10% by mass or less, preferably 9% by mass or less, more preferably 8% by mass or less, more preferably 7% by mass or less. More preferably 6% by mass or less, DW5 value is 50 ml / g or more, preferably more than 60 ml / g, and late absorption rate is 6 ml / g · min or more. In both cases where the SAP content was 55 mass% and 65 mass%, the fourth U-shaped absorption rate was 60 seconds or less. This indicates that the ability to rapidly absorb 80 ml of artificial urine is maintained even when the SAP content is increased. Therefore, the absorber 1 can be thinned.

  As described above, the repeated absorption performance of the absorbent body 1 is maintained by reducing the amount of particles having a particle diameter of less than 300 μm in the SAP particles 2. On the other hand, the SAP particles 2 having a particle diameter of less than 300 μm have a large surface area to volume ratio, and thus have a low absorption performance but a high absorption rate. Therefore, the amount of particles having a particle diameter of less than 300 μm in the SAP particles disposed on the skin-facing surface side of the absorbent body 1 is set to 10 mass% or less, and the particle diameter of the SAP particles 2 is increased from the skin-facing surface toward the non-facing surface. Is reduced, the absorbent body 1 having both high repetitive absorption performance and high absorption speed can be obtained. Such an absorbent body 1 is, for example, sieved the SAP particles using a sieve having an opening of 300 μm, and placed the SAP particles 2 that did not pass through the sieve on the skin facing surface side of the absorbent body 1 and passed through the sieve. It is obtained by arranging the SAP particles 2 on the non-skin facing surface side.

  The absorbent body 1 of the present invention can be used for all sanitary products that utilize the absorbent body 1 containing SAP. Examples of sanitary products include, but are not limited to, known disposable diapers, sanitary napkins, incontinence pads, and breast milk pads.

The present invention described above can be arranged in at least the following matters.
An absorbent body comprising a highly water-absorbing polymer particle, an absorbent core containing a water-absorbing fiber, and a sheet member covering the absorbent core, wherein the water-absorbing polymer particle has a water retention ratio of 37 g / g or more, Calculated from the time it takes for the water absorption polymer particles to absorb from 40 ml / g to 50 ml / g when the DW5 minute value, which is the absorption amount when the water-soluble polymer particles are immersed in physiological saline for 5 minutes, is 40 ml / g or more. The late absorption rate is 6 ml / g · min or more, the fine pressurization SFC, which is the liquid diffusion performance under slight pressurization, is 5 × 10 ⁻⁶ · ml · second or more, the water retention ratio × late absorption rate × slight pressurization SFC × The repeated absorbency index defined by 10 ³ is 2 or more.

The present invention disclosed in paragraph 0034 can include at least the following embodiments. The embodiments can be adopted separately or in combination with each other.
(1) The water retention ratio is 39 g / g or more.
(2) The DW5 minute value is 50 ml / g or more.
(3) Late absorption rate is 7 ml / g · min or more.
(4) Slight pressurization SFC is 7 × 10 ⁻⁶ · ml · second or more.
(5) The absorbent body contains 50 to 100% by mass of superabsorbent polymer particles and 0 to 50% by mass of water absorbent fibers.
(6) The amount of particles having a particle diameter of less than 300 μm contained in the superabsorbent polymer particles is 10% by mass or less.
(7) The absorbent body has a skin facing surface facing the user's skin and a non-skin facing surface facing the skin facing surface, and the particle diameter in the superabsorbent polymer particles located on the skin facing surface side is 300 μm. The amount of particles less than 10% by mass is less and the particle diameter of the superabsorbent polymer particles decreases from the skin facing surface toward the non-facing surface.
(8) A sanitary article comprising the absorbent body of the present invention.

In addition, the present invention can include the following embodiments. The embodiments can be adopted separately or in combination with each other.
(1) and superabsorbent polymer particles, and an absorbent core comprising an absorbent fibers, said absorbent core An absorbent body and a sheet member encapsulating, 5 minutes superabsorbent polymer particles in saline The DW5 value, which is the amount absorbed when immersed, is 50 ml / g or more, preferably greater than 60 ml / g, and is calculated from the time taken for the amount of absorption of the superabsorbent polymer particles to reach 50 ml / g from 40 ml / g. Late absorption rate is 6 ml / g · min or more, preferably 14 ml / g · min or more, preferably 16 ml / g · min or more, and the amount of particles having a particle diameter of less than 300 μm in the superabsorbent polymer particles is 10 mass % Or less, more preferably 9% by mass or less, more preferably 8% by mass or less, more preferably 7% by mass or less, and more preferably 6% by mass or less.
(2) The absorbent body contains 50 to 100% by mass of superabsorbent polymer particles and 0 to 50% by mass of water absorbent fibers.
(3) The absorbent body has a skin facing surface facing the user's skin and a non-skin facing surface facing the skin facing surface, and the particle diameter in the superabsorbent polymer particles located on the skin facing surface side is 300 μm. The amount of particles less than 10% by mass is less and the particle diameter of the superabsorbent polymer particles decreases from the skin facing surface toward the non-facing surface.
(4) A sanitary article comprising the absorbent body of the present invention.

DESCRIPTION OF SYMBOLS 1 Absorber 2 SAP particle 3 Water-absorbent fiber 4 Absorbent core 5 Sheet member

Claims (9)

An absorbent body comprising a superabsorbent polymer particle, an absorbent core containing a water absorbent fiber, and a sheet member covering the absorbent core,
The water retention ratio of the superabsorbent polymer particles is 37 g / g or more,
DW5 minute value, which is the amount absorbed when the superabsorbent polymer particles are immersed in physiological saline for 5 minutes, is 40 ml / g or more,
Late absorption rate calculated from the time when the amount of absorption of the superabsorbent polymer particles reaches 40 ml / g to 50 ml / g is 6 ml / g · min or more,
The fine pressure SFC, which is the liquid diffusion performance under slight pressure, is 5 × 10 ⁻⁶ · ml · second or more,
Absorbent body having a repetitive absorbency index of 2 or more defined by water retention ratio × late-term absorption rate × slightly pressurized SFC × 10 ³ .   The absorbent according to claim 1, wherein the water retention ratio is 39 g / g or more.   The absorber according to claim 1 or 2, wherein the DW5 value is 50 ml / g or more.   The absorber according to any one of claims 1 to 3, wherein the late absorption rate is 7 ml / g · min or more. The absorber according to any one of claims 1 to 4, wherein the slightly pressurized SFC is 7 x 10 ^-6 · ml · sec or more.   The absorber according to any one of claims 1 to 5, wherein 50 to 100% by mass of the superabsorbent polymer particles and 0 to 50% by mass of the water-absorbent fiber are contained in the absorber.   The absorber according to any one of claims 1 to 6, wherein the amount of particles having a particle diameter of less than 300 µm contained in the superabsorbent polymer particles is 10% by mass or less.   It is an absorber of any one of Claims 1-7, Comprising: It has the skin opposing surface which faces a user's skin, and the non-skin opposing surface which opposes the said skin opposing surface, The said skin opposing surface The amount of the particles having a particle diameter of less than 300 μm in the superabsorbent polymer particles located on the side is 10% by mass or less, and the particle diameter of the superabsorbent polymer particles from the skin facing surface toward the non-opposing surface Reduce the absorber.   A sanitary article provided with the absorber of any one of Claims 1-8.

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