JP4790232B2 - Absorber and disposable diaper equipped with the absorber - Google Patents

Description

  The present invention relates to an absorber used for a body fluid absorbent article such as a paper diaper and a sanitary napkin, and a paper diaper including the absorber.

  Conventionally, absorbent bodies used for body fluid absorbent articles are generally used in which superabsorbent polymer particles are dispersed and held in a pile of short pulp fibers (see, for example, Patent Document 1). In order to meet the demand for weight reduction and thickness reduction in such a conventional absorbent body, the amount of fibers in the absorbent body must be reduced at present.

However, when the amount of pulp used is reduced, the bulk of the absorbent body is remarkably reduced, and there is a problem that the stiffness is lost, the feeling of use is impaired, and the absorption performance is deteriorated and leaking easily occurs. Therefore, the conventional absorber has a limit in weight reduction and thickness reduction, and a fundamental improvement is desired.
JP 2004-65300 A

  Therefore, a main problem of the present invention is to make it possible to reduce the weight and thickness without impairing the feeling of use and the absorption performance.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
An absorbent body having a fiber assembly, a powdery superabsorbent polymer, and a wrapping sheet for wrapping them, and an upper surface on the body fluid receiving side and a lower surface on the opposite side formed by the wrapping sheet. And
As the fiber assembly, a fiber tow which is a bundle of continuous fibers of 5,000 to 1,000,000 cellulose acetates intertwined with each other is used,
The cellulose acetate continuous fibers are crimped fibers having an irregular cross section, having a fineness of 2 to 8 denier and a crimping degree of 15 to 50 pieces / inch,
A layer made of the superabsorbent polymer is provided via a first adhesive layer that spreads on the inner surface of the packaging sheet that forms the lower surface of the absorber, and a second adhesive layer that spreads thereon is provided. A layer composed of the fiber assembly is provided, and the inner surface of the packaging sheet forming the upper surface of the absorbent body is bonded thereon via an adhesive,
It does not contain the high absorbent polymer in a layer made of the fiber aggregate,
Part or all of the superabsorbent polymer in the layer composed of the superabsorbent polymer located below the layer composed of the fiber assembly is adhered and fixed to the inner surface of the packaging sheet by the first adhesive layer. And being bonded and fixed to the lower surface of the fiber assembly by the second adhesive layer,
The basis weight of the superabsorbent polymer is 0.02 to 0.030 g / cm ² ;
The basis weight of the fiber assembly is 0.0060 to 0.0075 g / cm ² ;
The compression energy WC is 4.0 to 7.0 gf · cm / cm ² and the compression resilience RC is 45 to 60%.
Absorber characterized by that.
<Invention of Claim 2>
An absorbent body having a fiber assembly, a powdery superabsorbent polymer, and a wrapping sheet for wrapping them, and an upper surface on the body fluid receiving side and a lower surface on the opposite side formed by the wrapping sheet. And
As the fiber assembly, a fiber tow which is a bundle of continuous fibers of 5,000 to 1,000,000 cellulose acetates intertwined with each other is used,
The cellulose acetate continuous fibers are crimped fibers having an irregular cross section, having a fineness of 2 to 8 denier and a crimping degree of 15 to 50 pieces / inch,
A layer made of the superabsorbent polymer is provided via a first adhesive layer that spreads on the inner surface of the packaging sheet that forms the lower surface of the absorber, and a second adhesive layer that spreads thereon is provided. A layer made of the fiber assembly is provided, and a layer made of the superabsorbent polymer is provided between the layer made of the fiber assembly and the inner surface of the packaging sheet forming the upper surface of the absorber. The superabsorbent polymer located above the body layer is bonded to the fiber assembly layer,
It does not contain the high absorbent polymer in a layer made of the fiber aggregate,
Part or all of the superabsorbent polymer in the layer composed of the superabsorbent polymer located below the layer composed of the fiber assembly is adhered and fixed to the inner surface of the packaging sheet by the first adhesive layer. And being bonded and fixed to the lower surface of the fiber assembly by the second adhesive layer,
The basis weight of the superabsorbent polymer is 0.02 to 0.030 g / cm ² ;
The basis weight of the fiber assembly is 0.0060 to 0.0075 g / cm ² ;
The compression energy WC is 4.0 to 7.0 gf · cm / cm ² and the compression resilience RC is 45 to 60%.
Absorber characterized by that.
<Invention of Claim 3>
The absorbent body according to claim 1 or 2, wherein the adhesive is applied in a continuous surface shape in a range of at least 80% of a portion where the superabsorbent polymer is provided in the packaging sheet.
<Invention of Claim 4>
The part where the superabsorbent polymer is provided in the packaging sheet is provided with a part where the adhesive is applied and a part which does not have a plurality of adhesives surrounded by the part where the adhesive is applied, The superabsorbent polymer adhered to the packaging sheet by a portion to which the adhesive is applied, and the superabsorbent polymer present in a portion not having the adhesive, 2. The absorber according to 2.

(Function and effect)
By setting the polymer basis weight to 0.03 g / cm ² or less, it is possible to prevent the lightening effect from being hardly exerted by adopting a fiber assembly made of tow depending on the weight of the polymer.
If the fiber basis weight is excessively high, it is difficult to reduce the weight even if a fiber assembly made of tow is used. Therefore, it is preferable to use a fiber assembly having a fiber basis weight within the range described in this section.

<Invention of Claim 2>
The absorber according to any one of claims 1 to 4, wherein the superabsorbent polymer has a water absorption amount of 60 g / g or more, a water absorption speed of 40 seconds or less, and a gel strength of 1000 Pa or more.

(Function and effect)
By using a fiber assembly composed of tows (fiber bundles) composed of fibers and a highly absorbent polymer with high water absorption, the amount of fiber used is reduced while suppressing a decrease in bulk, stiffness, and absorption performance. In addition to making it possible to reduce the weight and thickness, it is possible to compensate for the unavoidable decline in absorption performance by adopting a high-absorbency polymer that absorbs more water than is normally used. The amount of water absorption is as described later.
When the water absorption speed exceeds 40 seconds, the body fluid supplied into the absorbent body tends to cause a so-called reversal that returns to the outside of the absorbent body, and therefore, it is preferably 40 seconds or less. The water absorption rate is as described later.

  When a bulky absorbent body is formed by using tow, the amount of the superabsorbent polymer existing outside the fiber assembly must be increased. However, when such a superabsorbent polymer absorbs body fluids, it promotes a feeling of stickiness. Therefore, in order to suppress this feeling of stickiness, in the invention described in this section, the gel strength is set to 1000 Pa or higher, which is higher than that generally used conventionally. The gel strength is as described later.

<Invention of Claim 6>
The absorber according to any one of claims 1 to 5, wherein the planar projection area is 400 cm ² or more, the thickness is 1 cm or less, and the weight is 15 g or less.

(Function and effect)
In the present invention, when the size of the absorber is within such a range, it is easy to reduce the weight and thickness without impairing the absorption performance.

Even if the weight exceeds 15 g, there is an effect of using the fiber assembly made of tow itself, and if the weight is the same, the absorption performance is improved. However, at this weight, the influence of the weight of the fiber assembly on the weight of the absorber is reduced, and the significance of using a fiber assembly made of tow is diminished. Therefore, if the viewpoint of weight reduction is emphasized, the weight of the absorber is preferably 15 g or less.
<Invention of Claim 7>
A disposable diaper comprising the absorber according to any one of claims 1 to 6.

  As described above, according to the present invention, weight reduction and thickness reduction can be achieved without impairing the feeling of use and absorption performance.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
<Example structure of absorber>
FIG. 1 schematically shows an example of the structure of an absorbent body according to the present invention. This absorbent body 10 includes a fiber assembly 1 made of tow composed of fibers, a superabsorbent polymer 2, and these. And a wrapping sheet 3 for wrapping.

  More specifically, in the form shown in FIG. 1, a layer made of the superabsorbent polymer 2 is provided on the inner surface of the packaging sheet 3 via an adhesive 4, and a fiber assembly is further provided thereon via an adhesive 5. 1 is provided, and a packaging sheet 3 is bonded onto the fiber assembly 1 via an adhesive. The packaging sheet 3 in the illustrated example is configured so as to wrap the fiber assembly 1 and the superabsorbent polymer 2 by being folded back on both sides, but a form in which the packaging sheet 3 is sandwiched between two upper and lower packaging sheets can also be employed. .

  When the superabsorbent polymer 2 is bonded to the packaging sheet 3, it is preferable to apply the adhesive 4 in a continuous surface form on the entire surface or substantially the entire surface of the packaging sheet 3 where at least the superabsorbent polymer is provided. . Note that “substantially the entire surface” means 80% of the portion where the superabsorbent polymer is provided. In this case, part or all of the superabsorbent polymer 2 is bonded and fixed to the packaging sheet 3 by the adhesive 4. Moreover, the part which apply | coated the adhesive agent and the part which does not have the some adhesive agent enclosed by the part which apply | coated the adhesive agent are provided, and it adhere | attached with respect to the sheet | seat 3 by the part which apply | coated the adhesive agent It is also preferable to have a superabsorbent polymer and a superabsorbent polymer that exists in a portion that does not have an adhesive. In this case, most of the superabsorbent polymer 2 is constrained in a closed space that does not have an adhesive surrounded by a portion to which the adhesive is applied. In the case of applying the adhesive 4 in a continuous surface shape, curtain coating or roll coating can be used, and it does not have a plurality of adhesives surrounded by a portion where the adhesive is applied and a portion where the adhesive is applied. Spiral coating can be used when providing the portion.

Further, part or all of the superabsorbent polymer 2 is bonded and fixed to the lower surface of the fiber assembly 1 with an adhesive 5. In addition, the code | symbol 6 has shown the adhesive agent which adhere | attaches the surface on the opposite side to the polymer side surface of the fiber assembly 1, and the packaging sheet 3. FIG. As these adhesives, an adhesive made of a thermoplastic resin described in the section of the fiber assembly described later can be used.

  2 to 4 show other applications. The form shown in FIG. 2 is different from the form shown in FIG. 1 in that the superabsorbent polymer 7 is held in the fiber assembly 1 and is a comparative form not included in the present invention. . 3 differs from the embodiment shown in FIG. 1 in which the superabsorbent polymer 2 is provided only on the lower side of the fiber assembly 1 on the upper and lower sides of the fiber assembly 1, respectively. This is different. In this case, the superabsorbent polymer 9 positioned on the upper side of the fiber assembly 1 can be bonded and fixed to the fiber assembly 1 with the adhesive 8. The form shown in FIG. 4 is the one shown in FIG. 3 in which the superabsorbent polymer 7 is held in the fiber assembly 21 as in the form shown in FIG. 2, and is not included in the present invention. It is a comparative form.

Moreover, when using these absorbers for a bodily fluid absorbent article, as shown in FIG.1 and FIG.3, it uses so that the fiber assembly 1 side may become a bodily fluid receiving side.

  Moreover, FIG. 5 has shown the application example with respect to the paper diaper DP and sanitary napkin NP of the absorber of this invention. As shown in FIGS. 5 (a) and 5 (b), the absorbent body 10 is preferably provided so that the fiber continuous direction of the tow is along the longitudinal direction (front-rear direction) of the article. ), The fiber continuous direction of the tow can be provided along the width direction of the article.

<Fiber assembly>
The fiber assembly 1 used in the present invention is composed of tows (fiber bundles) composed of fibers.

  Cellulose acetate is used as the tow constituent fiber. The viscosity average polymerization degree of cellulose acetate is, for example, about 50 to 900, preferably about 200 to 800. The average substitution degree of cellulose acetate is, for example, about 1.5 to 3.0 (for example, 2 to 3).

  The average degree of polymerization of cellulose acetate can be, for example, 10 to 1000, preferably 50 to 900, more preferably about 200 to 800, and the average degree of substitution of cellulose acetate is, for example, about 1 to 3, preferably 1 to 1. 2.15, more preferably about 1.1 to 2.0. The average degree of substitution of cellulose acetate can be selected from the viewpoint of enhancing biodegradability.

  The degree of acetylation of cellulose acetate is often about 43 to 62%, but about 30 to 50% is particularly preferable because it is excellent in biodegradability.

  The tow constituent fiber may contain various additives such as a heat stabilizer, a colorant, an oil agent, a yield improver, a whiteness improver, and the like.

  The fineness of the tow constituent fibers is 2 to 8 denier. The tow constituent fiber is a crimped fiber. The crimping degree of the crimped fiber is 15 to 50 per inch. Further, a crimped fiber that is uniformly crimped is often used. When crimped fibers are used, a bulky and light absorbent body can be produced, and a tow with high unity can be easily produced by entanglement between the fibers. The cross-sectional shape of the tow constituent fibers is an irregular (eg, Y-shaped, X-shaped, I-shaped, R-shaped) cross section. The tow constituent fiber is used in the form of a tow (fiber bundle) formed by bundling 5,000 to 1,000,000 single fibers. The fiber bundle is formed by bundling 5,000 to 1,000,000 continuous fibers.

  Since the entanglement between fibers is weak, a binder having an action of adhering or fusing the contact portions of the fibers can be used mainly for the purpose of maintaining the shape. Examples of binders include ester plasticizers such as triacetin, triethylene glycol diacetate, triethylene glycol dipropionate, dibutyl phthalate, dimethoxyethyl phthalate, and triethyl citrate, as well as various resin adhesives, especially thermoplastic resins. Can be used.

  The thermoplastic resin is a resin that exhibits an adhesive force by melting and solidifying, and includes a water-insoluble or hardly water-soluble resin and a water-soluble resin. A water-insoluble or poorly water-soluble resin and a water-soluble resin can be used together as necessary.

  Examples of water-insoluble or poorly water-soluble resins include polyethylene, polypropylene, ethylene-propylene copolymers, olefinic homo- or copolymers such as ethylene-vinyl acetate copolymers, polyvinyl acetate, polymethyl methacrylate, methacryl Acid methyl-acrylic acid ester copolymer, acrylic resin such as copolymer of (meth) acrylic monomer and styrene monomer, polyvinyl chloride, vinyl acetate-vinyl chloride copolymer, polystyrene, styrene monomer ( Styrenic polymers such as copolymers with (meth) acrylic monomers, optionally modified polyesters, nylon 11, nylon 12, nylon 610, nylon 612 and other polyamides, rosin derivatives (eg, rosin esters), Hydrocarbon resin (eg terpene tree , Dicyclopentadiene resins, and petroleum resins), and hydrogenated hydrocarbon resins. One or two or more of these thermoplastic resins can be used.

  Examples of water-soluble resins include various water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl ether, vinyl monomers, and copolymerizable monomers having a carboxyl group, a sulfonic acid group, or a salt thereof. Vinyl water-soluble resins such as copolymers, acrylic water-soluble resins, polyalkylene oxides, water-soluble polyesters, water-soluble polyamides, and the like can be used. These water-soluble resins can be used alone or in combination of two or more.

  Various additives such as stabilizers such as antioxidants and ultraviolet absorbers, fillers, plasticizers, preservatives, and antifungal agents may be added to the thermoplastic resin.

  The fiber assembly of the present invention made of tow can be produced by a known method, and at that time, it is spread in a strip shape so as to have a desired size and bulk. The opening width of the tow is arbitrary, and can be, for example, about 100 to 2000 mm, preferably about 150 to 1500 mm. Moreover, the density of an absorber can be adjusted by adjusting the degree of tow opening.

  As a method for opening a tow, for example, a method in which a tow is passed over a plurality of opening rolls and the width of the tow is gradually expanded as the tow progresses, and tension (elongation) and relaxation of the tow ( (Shrinkage) can be repeated, and a method of widening and opening using compressed air can be used.

  FIG. 6 is a schematic diagram showing an example of the opening facility. In this example, the tow 21 that is the raw fabric is sequentially fed out, and in the process of transporting, the widening means 22 using compressed air and a plurality of spread nip rolls 23, 24, and 25 whose peripheral speed is faster as the downstream side roll is combined. After passing through the opened portion and widened / opened, the fiber is passed through the binder addition box 26, and the binder is added (for example, the box is filled with mist of triacetin), and the fibers are formed of tow having a desired width and density. The assembly 1 is formed.

The fiber assembly of the present invention, the fiber density at the time of a thickness of 10mm is 0.0075 g / cm ³ or less, it is suitable as a particularly 0.0060~0.0070g / cm ^3. If the fiber density is excessively high, it is difficult to reduce the weight and thickness even if a fiber assembly made of tow is used. The fiber density can be adjusted by the degree of opening described above.

Further, the basis weight of the fiber assembly of the present invention is 0.0060 to 0.0075 g / cm ² , and particularly preferably 0.0060 to 0.0070 g / cm ² . If the fiber basis weight is excessively high, it is difficult to reduce the weight even if a fiber assembly made of tow is used. The fiber basis weight can be adjusted by selecting a tow serving as a raw fabric or manufacturing conditions thereof.

<About superabsorbent polymer>
As the superabsorbent polymer 2, one having a water absorption of 60 g / g or more is used. Examples of superabsorbent polymers include starch-based, cellulose-based and synthetic polymer-based polymers. Starch-acrylic acid (salt) graft copolymer, saponified starch-acrylonitrile copolymer, cross-linked sodium carboxymethylcellulose And acrylic acid (salt) polymers can be used. As the shape of the superabsorbent polymer, a commonly used granular material is used.

  As the superabsorbent polymer 2, those having a water absorption rate of 40 seconds or less are preferably used. When the water absorption speed exceeds 40 seconds, so-called reversion in which the body fluid supplied into the absorbent body returns to the outside of the absorbent body tends to occur.

  As the superabsorbent polymer 2, a polymer having a gel strength of 1000 Pa or more is preferably used. Thereby, even if it is a case where it is set as a bulky absorber by using tow | toe, the sticky feeling after bodily fluid absorption can be suppressed effectively.

The basis weight of the superabsorbent polymer 2 is 0.02 to 0.03 g / cm ² in the present invention, but can be particularly preferably 0.025 to 0.010 g / cm ² . By setting the polymer basis weight to 0.03 g / cm ² or less, it is possible to prevent the lightening effect from being hardly exerted by adopting a fiber assembly made of tow depending on the weight of the polymer.

<Packaging sheet>
As the packaging sheet 3 used for the absorbent body 10, a liquid permeable sheet such as a crepe paper, a nonwoven fabric or a perforated sheet, or a liquid impermeable sheet such as a polyethylene film can be used.

<Absorber size and weight>
On the other hand, the size of the absorber 10 is preferably such that the planar projection area is 400 cm ² or more and the thickness is 1 cm or less. If the size of the absorber is within such a range, it is easy to reduce the weight and thickness without impairing the absorption performance. Moreover, it is preferable to comprise so that the weight of an absorber may be 15 g or less. When the weight of the absorber is 15 g or less, the effect of reducing the weight by using the fiber assembly made of tow becomes particularly remarkable.

<Compressive properties of absorber>
In the present invention, it is preferable that the compression resilience RC of the absorbent body 10 is in the range of 45 to 60%, particularly 50 to 60%. Thereby, even if it does not use a member only for restoration, it becomes possible to exhibit sufficient restoration property by the absorber itself.

Furthermore, the compression energy WC of the absorber 10 is preferably 4.0 to 7.0 gf · cm / cm ² . As a result, the packaging can be compressed to the same level or higher than before.

  These compression characteristics can be adjusted by adjusting the fiber density of the fiber assembly 1 by opening or the like, selecting a fiber material, selecting a kind of binder such as a plasticizer, adjusting the degree of processing, or a combination thereof.

  Table 1 shows an absorbent body (Example) according to the present invention using a fiber assembly made of cellulose acetate fiber tow, a general absorbent body (conventional example) using short fiber pulp, and cellulose acetate fiber The following measurement was performed about the absorber (comparative example) which is using the fiber assembly which consists of a tow but does not satisfy the conditions of the present invention. In Table 1, the evaluation results are also shown.

(Measurement of water absorption of super absorbent polymer)
In a 1 liter beaker containing a rotor, 500.00 ± 0.10 g of 0.9% aqueous sodium chloride solution (prepared by dissolving 9.00 g of reagent-grade sodium chloride in 991.0 g of ion-exchanged water) was added, and magnetic While stirring the liquid with a stirrer, add 2.000 ± 0.0002 g of sample, cover with Saran wrap and stir for 1 hour.
The beaker contents are filtered using a standard sieve (38 μm, 200 mmφ × 45 mm), and the gel remaining on the sieve is drained with a Teflon (registered trademark) plate and left for 15 minutes. The weight A of the gel remaining on the sieve is measured, and the amount of water absorption is calculated by the following formula.
C = A / S (1)
Here, C is the amount of raw water absorbed (g / g), A is the weight of the gel remaining on the sieve (g), and S is the sample weight (g).

(Measurement of water content of superabsorbent polymer)
About 80% of 0.9% sodium chloride aqueous solution is put into a stainless steel container.
A sample 2.0000 ± 0.0002 g is precisely weighed and placed in a cotton bag (Membrode # 60 100 mm × 200 mm), and then about 100 ml of 0.9% sodium chloride aqueous solution is poured into the cotton bag. Is immersed in an aqueous solution in a stainless steel container.
The upper part of the cotton bag is tied with a rubber band and immersed for 15 minutes, then dehydrated with a dehydrator (167G) for 1 minute, and the weight of the cotton bag and gel is measured.
The same operation is performed without putting a sample, and the wet weight of an empty cotton bag is measured.
The water retention amount is calculated by the following formula.
C = (A−B) / S (2)
Here, C: water retention amount (g / g), A: weight of cotton bag and gel (g), B: weight of wet cotton bag when wet (g), and S: sample weight (g).

(Measurement of absorption rate of superabsorbent polymer)
Add 50.00 ± 0.01 g of 0.9% aqueous sodium chloride solution to a 100 ml beaker containing a rotor, and keep the temperature constant at 25 ± 0.2 ° C. in a constant temperature water bath.
Stir at a rotational speed of 600 ± 10 rpm using a magnetic stirrer and rotator.
2.000 ± 0.0002 g of sample is weighed and put into a vortex in a beaker, and measurement with a stopwatch is started at the same time. Record the time (seconds) from when the vortex disappears until the liquid level becomes horizontal, and use it as the absorption speed.

(Measurement of absorption amount of superabsorbent polymer under pressure)
As shown in FIG. 7, an acrylic resin cylinder 203 (with an inner diameter of 2 cm, a height of 5 cm, and a 75 μm nylon net 201N attached to the bottom) with the center aligned with the upper and lower through holes in the center of the support base 201, A sample 200 of 0.100 ± 0.0002 g is placed in the cylinder 203, and a cylindrical weight 202 (diameter 1.9 cm, weight 120 g) is placed on the sample 200.
The outlet of the burette 204 is connected to the lower opening of the through hole of the support base 201 by a conduit 206, and the scale value before opening the valves V1 and V2 and the scale value after 30 minutes are read.
The absorption under pressure is calculated by the following formula.
C = (A−B) / S (3)
Here, C: absorption amount under pressure (ml / g), A: scale value (ml) 30 minutes after the start of water absorption, B: scale value (ml) before water absorption, S: sample weight (g).

(Measurement of gel strength of superabsorbent polymer)
20.0 g of urea, 8.0 g of sodium chloride, 0.3 g of calcium chloride, 0.8 g of magnesium sulfate, 970.9 g of ion-exchanged water, and 0.25 g of ferrous sulfate were mixed to make a total of 1 liter of human urine ( Iron ions 50 ppm).
Add 49 ± 0.1 g of artificial urine containing 50 ppm of iron ions to a 100 ml beaker containing a rotor, and stir using a magnetic stirrer. A sample 1.0000 ± 0.0002 g is weighed and put into a vortex in a beaker, and then stirred until the vortex disappears and the liquid level becomes horizontal.
The produced gel is left in a constant temperature and humidity machine of 40 ° C. × 60% RH for 3 hours.
After immersing in a constant temperature water bath at 25 ° C. for 5 minutes, the gel strength is measured with a neo-card meter. The measured value is converted into a unit by the following formula, and the gel strength (Pa) is calculated.
C = A × 0.1 (4)
Here, C: gel strength (Pa), A: gel strength (dyne / cm ² ) obtained from a neocardometer, and 0.1: constant.

(Measurement of absorption under pressure in diapers)
First, the weight of the unabsorbed sample is measured.
Next, as shown in FIG. 8, in the sample diaper 100, a portion that shrinks with rubber thread or the like, for example, the waist portion 101, the leg periphery portion 102, and the gather portion 103 are cut at intervals of 2 cm as shown by dotted lines. , Make the diaper flattened unnaturally (naturally).
Human urine with the use surface (inner surface) facing up, a sample sandwiched flat between an acrylic plate and a metal plate, a weight (10 kg) placed on the acrylic plate, and maintained at 37 ° C. (as described above) Immerse in for 30 minutes.
After 30 minutes, the sample is pulled up from the human urine, the weight and the acrylic plate are removed, and then the sample is folded in three and placed on a scale to measure the weight.
The amount of absorption under pressure (g) is calculated by subtracting the unabsorbed sample weight from the sample weight after absorption.

(Measurement of absorption rate in diapers (hang method))
A U-shaped instrument is used which is made of a U-shaped plate formed assuming a portion extending from the crotch to the buttocks, and has an injection port formed at the center in the width direction at the lowest position.
Mark the longitudinal center position of the absorbent body in the sample diaper and align the mark position with the inlet to secure the sample to the outer surface of the U-shaped instrument.
Place a U-shaped instrument with a fixed sample on the hammock so that it does not tilt.
A weight (1 kg, 10 cm × 10 cm) having a through hole in the center is placed on the U-shaped instrument. At this time, the through hole of the weight is aligned with the inlet of the U-shaped instrument.
100 cc of artificial urine (as described above) is injected into the sample through the weight through hole and the injection port of the U-shaped instrument, and the time required for absorption of the entire amount is measured to obtain the absorption rate (seconds).

(Measurement of the amount of return in diapers)
A top sheet is placed on an absorber cut to 100 mm × 300 mm, and four sides are sealed to obtain a sample.
A cylindrical instrument (support 150 mm × 150 mm) with an inner diameter of 27 mm is placed in the center of the sample. The cylindrical instrument is weighted as necessary.
Artificial urine is dropped 3 times at an interval of 10 minutes in an amount of 50 cc.
Ten minutes after the third dropping, a filter paper (ADVANTEC No. 2, 10 cm × 10 cm, 30 sheets stacked) was put on, and after applying a load with a 5 kg weight for 10 seconds, the weight of the kitchen paper was measured and measured in advance. By subtracting the weight of the unabsorbed kitchen paper, the amount of human urine transferred to the kitchen paper is calculated and used as the reversal amount (g).

(Measurement of compression resilience RC and compression energy WC)
Using a compression tester manufactured by Kato Tech Co., Ltd., the sample was compressed under the conditions of speed: 0.01 cm / sec, compression area: 2 cm ² , sensitivity: 2 (force meter 200 g / 10v), compression load: 50 gf / cm 2. The compression resilience RC and the compression energy WC are calculated from the correlation diagram between the pressure and the deformation amount. The compression resilience RC means that the greater the value, the higher the recoverability after compression, and the compression energy WC means that the greater the value, the easier the compression.

(Sensory evaluation of resilience)
Paper diaper samples were manufactured using each absorbent body and using the same structure except for the absorbent body. What was not compressed after manufacture and what was unpacked after being compressed and packaged in a common form were prepared, and the restorability was evaluated visually and touched by 20 subjects. Evaluation was based on the conventional example, and in comparison with this, the case where almost no change was felt was indicated by Δ, and the case where the restoration property was high and the flexibility was high was indicated by ○.

  The present invention is suitable for absorbents of body fluid absorbent articles such as paper diapers and sanitary napkins and the production thereof, but can be applied to other uses within the scope of the present invention.

It is a longitudinal cross-sectional view which shows the structural example of an absorber roughly. It is a longitudinal cross-sectional view which shows the structural example of an absorber roughly. It is a longitudinal cross-sectional view which shows the structural example of an absorber roughly. It is a longitudinal cross-sectional view which shows the structural example of an absorber roughly. It is the schematic which shows the various forms of an absorber. It is the schematic which shows the manufacturing flow of a fiber assembly. It is a front view which shows roughly the measuring method of the amount of absorption under pressure of a superabsorbent polymer. It is a top view which shows roughly the measuring method of the absorbed amount under pressure in a diaper state.

  DESCRIPTION OF SYMBOLS 1 ... Fiber assembly, 2, 7, 9 ... Super absorbent polymer, 3 ... Packaging sheet, 4-6 ... Adhesive, 10 ... Absorber.

Claims (7)

An absorbent body having a fiber assembly, a powdery superabsorbent polymer, and a wrapping sheet for wrapping them, and an upper surface on the body fluid receiving side and a lower surface on the opposite side formed by the wrapping sheet. And
As the fiber assembly, a fiber tow which is a bundle of continuous fibers of 5,000 to 1,000,000 cellulose acetates intertwined with each other is used,
The cellulose acetate continuous fibers are crimped fibers having an irregular cross section, having a fineness of 2 to 8 denier and a crimping degree of 15 to 50 pieces / inch,
A layer made of the superabsorbent polymer is provided via a first adhesive layer that spreads on the inner surface of the packaging sheet that forms the lower surface of the absorber, and a second adhesive layer that spreads thereon is provided. A layer composed of the fiber assembly is provided, and the inner surface of the packaging sheet forming the upper surface of the absorbent body is bonded thereon via an adhesive,
It does not contain the high absorbent polymer in a layer made of the fiber aggregate,
Part or all of the superabsorbent polymer in the layer composed of the superabsorbent polymer located below the layer composed of the fiber assembly is adhered and fixed to the inner surface of the packaging sheet by the first adhesive layer. And being bonded and fixed to the lower surface of the fiber assembly by the second adhesive layer,
The basis weight of the superabsorbent polymer is 0.02 to 0.030 g / cm ² ;
The basis weight of the fiber assembly is 0.0060 to 0.0075 g / cm ² ;
The compression energy WC is 4.0 to 7.0 gf · cm / cm ² and the compression resilience RC is 45 to 60%.
Absorber characterized by that. An absorbent body having a fiber assembly, a powdery superabsorbent polymer, and a wrapping sheet for wrapping them, and an upper surface on the body fluid receiving side and a lower surface on the opposite side formed by the wrapping sheet. And
As the fiber assembly, a fiber tow which is a bundle of continuous fibers of 5,000 to 1,000,000 cellulose acetates intertwined with each other is used,
The cellulose acetate continuous fibers are crimped fibers having an irregular cross section, having a fineness of 2 to 8 denier and a crimping degree of 15 to 50 pieces / inch,
A layer made of the superabsorbent polymer is provided via a first adhesive layer that spreads on the inner surface of the packaging sheet that forms the lower surface of the absorber, and a second adhesive layer that spreads thereon is provided. A layer made of the fiber assembly is provided, and a layer made of the superabsorbent polymer is provided between the layer made of the fiber assembly and the inner surface of the packaging sheet forming the upper surface of the absorber. The superabsorbent polymer located above the body layer is bonded to the fiber assembly layer,
It does not contain the high absorbent polymer in a layer made of the fiber aggregate,
Part or all of the superabsorbent polymer in the layer composed of the superabsorbent polymer located below the layer composed of the fiber assembly is adhered and fixed to the inner surface of the packaging sheet by the first adhesive layer. And being bonded and fixed to the lower surface of the fiber assembly by the second adhesive layer,
The basis weight of the superabsorbent polymer is 0.02 to 0.030 g / cm ² ;
The basis weight of the fiber assembly is 0.0060 to 0.0075 g / cm ² ;
The compression energy WC is 4.0 to 7.0 gf · cm / cm ² and the compression resilience RC is 45 to 60%.
Absorber characterized by that.   The absorbent body according to claim 1 or 2, wherein the adhesive is applied in a continuous surface shape in a range of at least 80% of a portion where the superabsorbent polymer is provided in the packaging sheet.   The part where the superabsorbent polymer is provided in the packaging sheet is provided with a part where the adhesive is applied and a part which does not have a plurality of adhesives surrounded by the part where the adhesive is applied, The superabsorbent polymer adhered to the packaging sheet by a portion to which the adhesive is applied, and the superabsorbent polymer present in a portion not having the adhesive, 2. The absorber according to 2.   The absorber according to any one of claims 1 to 4, wherein the superabsorbent polymer has a water absorption amount of 60 g / g or more, a water absorption speed of 40 seconds or less, and a gel strength of 1000 Pa or more. The absorber according to any one of claims 1 to 5, wherein the planar projection area is 400 cm ² or more, the thickness is 1 cm or less, and the weight is 15 g or less.   A disposable diaper comprising the absorber according to any one of claims 1 to 6.

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