JP2013252330A - Absorbing body and absorbing article with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin absorbing body having bulky fiber layer having stable strength.SOLUTION: In an absorbing body 4 having an absorbing core 20 having liquid absorbability and a core wrap sheet 30 covering the absorbing core 20, the absorbing core 20 includes a fiber layer 21 mainly comprising thermoplastic fiber 211 and highly absorbable polymer particle 22 arranged while dispersed in the fiber layer 21, the thermoplastic fiber is a kind of sheath/core type thermoplastic fiber 211, the fiber layer 21 has a 3D network structure formed by thermally fusing a part of the thermoplastic fiber 211, an absorbing speed of the highly absorbable polymer particle 22 by a Vortex method is 20 sec or less, and the thermoplastic fiber 211 constituting the fiber layer 21 is crimped by a crimping rate of 10% to 40%.

Description

  The present invention relates to an absorbent body and an absorbent article including the absorbent body.

Conventionally, in absorbent articles such as disposable diapers and sanitary napkins, an absorbent body made of cellulose-based hydrophilic fiber material such as pulp and highly absorbent polymer particles dispersed in the hydrophilic fiber material is used. ing. In such an absorbent body, the liquid such as urine excreted from the wearer wearing the absorbent article is first absorbed by the hydrophilic fiber material having a high absorption rate, and then absorbed by the superabsorbent polymer particles. The
Further, the absorbent body is configured to include a fiber layer made of thermoplastic fibers and superabsorbent polymer particles dispersed and arranged in the fiber layer, and the content of the superabsorbent polymer particles is increased. Therefore, a technique for keeping the liquid absorbency high while reducing the thickness of the absorber has also been proposed (see, for example, Patent Document 1).

JP-A-10-118113

  By the way, in an absorbent body in which a fiber layer is formed of thermoplastic fibers, as many voids as possible are formed between the thermoplastic fibers to form a bulky fiber layer, and many highly absorbent polymer particles are held in these voids. It is also preferable to increase the liquid holding capacity in the fiber layer. On the other hand, in order to maintain the stability of the shape as the absorbent body, it is necessary to ensure the strength of the fiber layer by stably heat-sealing the entangled portions of the thermoplastic fibers constituting the fiber layer.

  Therefore, an object of the present invention is to provide a thin absorbent body having a bulky and stable fiber layer and having excellent liquid absorbability and an absorbent article comprising the absorbent body.

  The present invention is an absorbent body comprising an absorbent core having liquid absorbability and a core wrap sheet covering the absorbent core, wherein the absorbent core is a fiber layer mainly composed of thermoplastic fibers, Superabsorbent polymer particles dispersed in the fiber layer, and the thermoplastic fiber is a kind of seascore-type thermoplastic fiber, and the fiber layer is made of the thermoplastic fiber. The superabsorbent polymer particles have a three-dimensional network structure partly formed by heat fusion, the absorption rate by the Vortex method is 20 seconds or less, and the thermoplastic fiber constituting the fiber layer is The present invention relates to an absorber having a crimp rate of 10% to 40%.

  Moreover, it is preferable that the thermoplastic fiber is a crimped fiber to which crimpability is imparted by performing mechanical crimping.

  The absorber further includes a liquid permeable layer disposed on one surface side of the fiber layer, and the liquid permeable layer is configured by entangled crimped fibers having a porosity of 70% or more and 90% or less. It is preferable.

  Moreover, it is preferable that the said thermoplastic fiber has a hollow part.

  Moreover, it is preferable that the said absorptive core is formed with 40 weight%-5 weight% thermoplastic fiber, and 60 weight%-95 weight% superabsorbent polymer particle.

Moreover, it is preferable that the basic weight of the whole fiber contained in the said fiber layer is 20-100 g / m < ² >.

The core wrap sheet is preferably a hydrophilic sheet having a basis weight of 20 g / m ² or less.

The specific surface area of the superabsorbent polymer particles is preferably at least 0.03 m ² / g.

  The water retention of the superabsorbent polymer particles is preferably at least 20 g / g.

  Moreover, this invention relates to an absorbent article provided with the absorber in any one mentioned above, and a liquid-impermeable back surface sheet | seat arrange | positioned at one surface of this absorber.

  ADVANTAGE OF THE INVENTION According to this invention, the thin absorber which is equipped with the fiber layer which is bulky and has the stable intensity | strength, and is excellent in a liquid absorbency can be provided.

It is a top view which shows a disposable diaper provided with the absorber which concerns on 1st Embodiment of this invention. It is the XX sectional view taken on the line of FIG. It is sectional drawing of the absorber which concerns on 2nd Embodiment of this invention.

Hereinafter, preferred embodiments of the absorber of the present invention will be described with reference to the drawings.
Drawing 1 is a top view which looked at disposable diaper 1 in which the absorber concerning the present invention is used from the surface sheet side.
The disposable diaper 1 includes a liquid-permeable top sheet 2 made of a nonwoven fabric or a perforated plastic film, a liquid-impermeable back sheet 3 made of a plastic film, and an absorbent body 4 disposed between the two sheets 2 and 3. And comprising. The disposable diaper 1 is formed in a rectangular shape with a constricted central portion in the longitudinal direction LD.

  The top sheet 2 and the back sheet 3 constitute the outer shape of the disposable diaper 1 and have portions extending from the periphery of the absorbent body 4. The top sheet 2 and the back sheet 3 are joined by a hot melt adhesive at a portion extending from the periphery of the absorber 4.

The disposable diaper 1 is positioned between a front waistline region 6 disposed on one end side in the longitudinal direction LD, a rear waistline region 7 disposed on the other end side in the longitudinal direction LD, and the both waistline regions 6, 7. And a crotch region 8.
Elastic members 11, 12 extending in the waist direction, which is the width direction WD, are disposed between the top sheet 2 and the back sheet 3 at the edge portions of the front waist region 6 and the back waist region 7. The elastic members 11 and 12 are attached to at least one inner surface of the top sheet 2 and the back sheet 3 in an extended state.

A leg-around elastic member 13 is disposed between the top sheet 2 and the back sheet 3 at the side edge of the crotch region 8. The leg-hole elastic member 13 is attached to at least one inner surface of the top sheet 2 and the back sheet 3 in an extended state.
Tape fasteners 14 are attached to both side edges of the rear waistline region 7.

FIG. 2 is a cross-sectional view taken along the line XX in FIG.
The absorbent body 4 includes an absorbent core 20 and a core wrap sheet 30 that covers the absorbent core 20. This absorber 4 is a thin absorber 4 having a thickness of 1 mm to 5 mm.
The absorbent core 20 is formed in a sheet shape and constitutes a main part of the absorbent body 4. The absorbent core 20 includes a fiber layer 21 and superabsorbent polymer particles 22.

The fiber layer 21 is mainly composed of thermoplastic fibers 211. Further, the thermoplastic fiber 211 constituting the fiber layer 21 is one kind of thermoplastic fiber 211. As this thermoplastic fiber 211, a sea core type thermoplastic fiber comprising a sheath part made of a low melting point component and a core part made of a high melting point component and covering the sheath part is used. The thermoplastic fiber 211 is a crimped fiber crimped at a crimping rate of 10% to 40%. The crimp rate is measured according to the contents described in JIS L1015 (crimp rate and residual crimp rate). In the first embodiment, the seascore-type thermoplastic fiber 211 is subjected to mechanical crimping to impart crimpability.
Mechanical crimping means that the spun fiber is subjected to mechanical crimping using a crimper (high input speed and low take-off speed).

The fiber layer 21 has a three-dimensional network structure in which a part of the thermoplastic fiber 211 having a crimp rate of 10% to 40% is thermally fused. In the first embodiment, hot air having a temperature near the melting point of the sheath portion or hot air having a temperature exceeding the melting point is blown onto a fiber web in which the thermoplastic fibers 211 subjected to the mechanical crimping process are stacked to a predetermined thickness. Thus, a part of the thermoplastic fiber 211 is thermally fused to form a three-dimensional network structure.
As the thermoplastic fiber 211 constituting the fiber layer 21, one having a fineness of 0.5 dtex to 20 dtex is preferably used. Further, from the viewpoint of improving the water absorption of the fiber layer 21, the thermoplastic fiber 211 is preferably subjected to a hydrophilic treatment. Moreover, it is preferable that the basic weight of the whole fiber contained in the fiber layer 21 is 20 g-100 g / m < ² >, and the apparent density of the fiber layer 21 is 0.01 g-0.05 g / cm < ³ >. preferable.
The fiber length of the thermoplastic fiber 211 is preferably 30 mm to 60 mm.

  As the thermoplastic fiber 211, for example, the core portion is made of a polyester component having a melting point of about 250 ° C., and the sheath portion is made of a polyester component having a melting point of about 160 ° C. Further, a machine crimped one is used. Further, as the thermoplastic fiber 211, a sea core type composite fiber having a hollow portion may be used. By using a sea core type composite fiber having a hollow portion as the thermoplastic fiber 211, the bulkiness and softness of the fiber layer 21 can be further improved.

The superabsorbent polymer particles 22 are dispersed and arranged in the fiber layer 21. As the superabsorbent polymer particles 22, it is preferable to use particles having a particle size of 100 μm to 1000 μm and a water retention of at least 20 g / g.
The superabsorbent polymer particles 22 contain 20 wt% to 100 wt% of particles having an absorption rate of 20 seconds or less, preferably 10 seconds or less, as measured by the Vortex method according to JIS K 7224.

  The absorption rate by the Vortex method is represented by the time required for 2.0 g of the superabsorbent polymer particles 22 to absorb 50 g of 0.9% physiological saline. The water retention rate of the superabsorbent polymer particles 22 is obtained by immersing 1 g of the superabsorbent polymer particles 22 in 1 l of 0.9% physiological saline for 1 hour, draining for 15 minutes, and then centrifuging at 850 rpm for 90 seconds. Represented by the weight of

The preferred specific surface area of the superabsorbent polymer particles 22 (measured using Micrometrics Autopore III 9420) is at least 0.03 m ² / g, more preferably at least 0.07 m ² / g.
By setting the specific surface area of the superabsorbent polymer particles 22 to 0.03 m ² / g, the superabsorbent polymer particles 22 can be easily caught on the thermoplastic fibers 211, and can hardly be detached from the fiber layer 21. Moreover, since the surface area becomes relatively large, the absorption rate can be improved.

  In the first embodiment, the superabsorbent polymer particles 22 are stacked together with the thermoplastic fibers 211 and are dispersedly arranged in the thermoplastic fibers 211. Thereafter, the fiber layer 21 is formed by thermally fusing the thermoplastic fibers 211, and the superabsorbent polymer particles 22 are dispersedly arranged in the fiber layer 21.

  The absorbent core 20 described above is formed by 40% to 5% by weight of thermoplastic fibers 211 and 60% to 95% by weight of superabsorbent polymer particles 22.

The core wrap sheet 30 covers the upper surface (surface on the surface sheet 2 side), the lower surface (surface on the back sheet 3 side), and the side surface of the absorbent core 20. The core wrap sheet 30 is composed of a hydrophilic sheet having a basis weight of 20 g / m ² or less. Specifically, the core wrap sheets 30, basis weight 20 g / m ² or less tissue sheets and a basis weight of 15 g / m ² or less hydrophilic treated SMS used (spunbond - - Merutoburon spunbond) nonwoven be able to.
In 1st Embodiment, as shown in FIG. 2, the core wrap sheet | seat 30 coat | covers so that the absorbent core 20 may be wrapped from the upper surface side of the absorbent core 20, and the edge part of the core wrap sheet | seat 30 is an absorbent core. 20 has an overlapping portion on the lower surface side.

  As for the absorber 4, the core wrap sheet | seat 30 is joined to the surface sheet 2 and the back surface sheet 3 via the hot-melt-adhesive. In addition to fixing the position of the absorbent body 4 by joining the core wrap sheet 30 to the top sheet 2 and the back sheet 3, the adhesion between the absorbent body 4 and the top sheet 2 is improved, and the excreted liquid Quickly penetrates into the absorber 4.

  In the disposable diaper 1 described above, the moisture that has penetrated the absorbent core 20 through the top sheet 2 and the core wrap sheet 30 flows through the gaps in the fiber layer 21 having a network structure, and thus the superabsorbent polymer particles. 22 is absorbed. Here, the superabsorbent polymer particles 22 are dispersed and held in the network structure of the fiber layer 21. As a result, when the superabsorbent polymer particles 22 absorb moisture, it is difficult to prevent mutual swelling or form a gel block to inhibit moisture penetration into the interior of the absorbent core 20.

  According to the absorber 4 of 1st Embodiment demonstrated above, there exist the following effects.

  One type of seascore-type thermoplastic fiber 211, and the fiber layer 21 is composed of the thermoplastic fiber 211 having a crimp rate of 10% to 40%, and the absorption rate by the Vortex method is 20 seconds on the fiber layer 21 The following superabsorbent polymer particles 22 were dispersed to form the absorber 4. Thereby, since the fiber layer 21 can be comprised with the thermoplastic fiber 211 of a single melting | fusing point, the thermoplastic fibers 211 can be thermally welded stably and the intensity | strength of the fiber layer 21 can be maintained stably. Moreover, since the fiber layer 21 was comprised with the thermoplastic fiber 211 with a crimp rate of 10%-40%, the fiber layer 21 can be formed bulky. Furthermore, since the high-absorbent polymer particles 22 having an absorption rate of 20 seconds or less by the Vortex method are dispersed in the fiber layer 21, the absorption rate of the liquid can be improved. Therefore, it is possible to realize a thin absorbent body 4 that is bulky and has stable strength and excellent liquid absorbability.

  The thermoplastic fiber was constituted by a crimped fiber to which crimpability was imparted by mechanical crimping. Thereby, the thermoplastic fiber 211 in the crimped state can be thermally fused to form a three-dimensional network structure, so that the stability of the shape of the fiber layer 21 can be further improved.

  Next, an absorber 4A according to a second embodiment of the present invention will be described with reference to FIG. In the description of the second embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted or simplified.

The absorbent body 4A of the second embodiment is different from the first embodiment in that it includes a liquid permeable layer 40 disposed on the surface of the absorbent core 20 on the surface sheet 2 side.
The liquid permeable layer 40 is an aggregate of crimped fibers having a porosity of 93.5% or more and 99.9% or less, and more specifically, is composed of crimped fibers that are entangled irregularly.

  When the porosity of the liquid permeable layer 40 is less than 93.5%, the crimped fibers have a small degree of crimping, and the amount of compressive deformation is reduced, making it difficult to adapt to the shape of the body. Moreover, the liquid permeability to the absorbent core 20 of the liquid which permeate | transmitted the surface sheet 51 tends to be inhibited. Moreover, when the porosity of the liquid permeable layer 40 exceeds 99.9%, the amount of crimped fibers directed in the thickness direction between the topsheet 2 and the absorbent core 20 decreases, and the topsheet 2 The function of drawing body fluid into the absorbent core 20 is reduced.

The porosity of the liquid permeable layer 40 is calculated by the following equation.
Porosity (%) = (1−volume ratio) × 100
Here, the volume ratio is calculated by the following equation.
Volume ratio = density / fiber specific gravity (fiber specific gravity was calculated as 1.0 g / cm ³ )
The density is calculated by the following formula.
Density (g / cm ³ ) = basis weight of the liquid permeable layer / thickness of the liquid permeable layer The basis weight of the liquid permeable layer is obtained by sampling a measurement sample having a certain size (for example, 10 cm × 10 cm) and sampling the sample. Calculation was performed by measuring the weight of the sample. The average value of the measured values at N = 10 was defined as the basis weight of the liquid permeable layer.
The thickness of the liquid permeable layer was measured using an automated compression tester “KES FB-3A” manufactured by Kato Tech Co., Ltd. The sample for measurement is placed in a testing machine, and the thickness when the pressure applied to the sample by the measuring terminal is “0.5 g / cm ² ” is measured. Let the average value of the measured value in N = 10 be the thickness of a liquid-permeable layer.

  As the crimped fiber constituting the liquid permeable layer 40, a thermoplastic fiber made of a thermoplastic resin such as a homo PP (polypropylene) resin, a block PP (polypropylene) resin, or a high density PE (polyethylene) resin can be used.

  According to 4 A of absorbers of 2nd Embodiment, there exist the following effects other than the same effect as 1st Embodiment.

  The absorbent body 4A was configured to include a liquid permeable layer 40 made of crimped fibers. Thereby, the softness of the tactile sensation on the skin side of the absorbent body 4 </ b> A can be improved by disposing the bulky liquid permeable layer 40 on the skin side of the fiber layer 21.

  As mentioned above, although each preferred embodiment of the present invention was described, the present invention is not limited to each embodiment mentioned above, and can be changed suitably.

  For example, in 1st Embodiment and 2nd Embodiment, although the fiber layer 21 was comprised only with the thermoplastic fiber 211, it is not restricted to this. That is, you may comprise a fiber layer including cellulosic hydrophilic fiber materials, such as a pulp. When the fiber layer is constituted by including pulp or the like, the proportion of pulp or the like contained in the fiber layer is preferably 40% by weight or less, and 30% by weight or less from the viewpoint of reducing the thickness of the absorber. It is more preferable.

  Moreover, in 1st Embodiment and 2nd Embodiment, although the absorbers 4 and 4A of this invention were applied to the deployment-type disposable diaper, it is not restricted to this. That is, the absorbent body of the present invention may be applied to a pants-type disposable diaper, or may be applied to other absorbent articles such as sanitary napkins and urine pads.

DESCRIPTION OF SYMBOLS 1 Disposable diaper 2 Top sheet 3 Back sheet 4, 4A Absorber 20 Absorbent core 21 Fiber layer 22 Super absorbent polymer particle 30 Core wrap sheet 40 Liquid permeable layer 211 Thermoplastic fiber

Claims (10)

An absorbent body comprising an absorbent core having liquid absorbency and a core wrap sheet covering the absorbent core,
The absorbent core is
A fiber layer mainly composed of thermoplastic fibers;
Superabsorbent polymer particles dispersed and disposed in the fiber layer,
The thermoplastic fiber is a type of seascore-type thermoplastic fiber, and the fiber layer has a three-dimensional network structure formed by thermally fusing part of the thermoplastic fiber,
The superabsorbent polymer particles have an absorption rate by the Vortex method of 20 seconds or less,
The thermoplastic fiber which comprises the said fiber layer is an absorber which has a crimp rate of 10%-40%.   The absorbent body according to claim 1, wherein the thermoplastic fiber is a crimped fiber imparted with crimpability by being subjected to mechanical crimping. A liquid permeable layer disposed on one side of the fiber layer;
The absorbent body according to claim 1 or 2, wherein the liquid permeable layer is constituted by entangled crimped fibers having a porosity of 70% or more and 90% or less.   The absorbent body according to any one of claims 1 to 3, wherein the thermoplastic fiber has a hollow portion.   5. The absorbent core according to claim 1, wherein the absorbent core is formed of 40 wt% to 5 wt% thermoplastic fiber and 60 wt% to 95 wt% superabsorbent polymer particles. Absorber. The basis weight of the total fibers contained in the fiber layer, absorbent body according to any one of claims 1 to 5 is 20g~100g / ^{m 2.}   The absorbent core according to claim 1, wherein the core wrap sheet is a hydrophilic sheet having a basis weight of 20 g / m 2 or less. The absorber according to any one of claims 1 to 8, wherein a specific surface area of the superabsorbent polymer particles is at least 0.03 m ² / g.   The absorbent according to any one of claims 1 to 9, wherein the water retention of the superabsorbent polymer particles is at least 20 g / g. An absorptive article provided with the absorber according to any one of claims 1 to 9, and a liquid impermeable back sheet arranged on one side of the absorber.

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