DE202012102095U1 - Absorbent article - Google Patents

Abstract

An absorbent article comprising a backsheet and an absorbent core disposed on the backsheet, the absorbent core comprising: an absorbent core disposed on both sides of the absorbent core layer, the absorbent core layer comprising: superabsorbent polymers having one Basis weight of 50 g / m2 or more; Pulp fibers with a basis weight of 50 g / m 2 or less and each of the liquid-permeable layers arranged on one of the two sides being constructed from interwoven crimped fibers, the pore rate of which is between 93.5% and 99.9% inclusive.

Description

This application is based on and claims priority from Japanese Patent Application No. Hei. JP 2012-130300 with filing date of 8 June 2012, the contents of which application being incorporated herein by reference.

The field of the invention

The present invention relates to an absorbent article such as a sanitary napkin, a panty liner and a disposable diaper.

State of the art

In recent years, sanitary napkins, panty liners, urine absorbent pads, disposable diapers and the like have been used as absorbent articles for absorbing excrement. As a common embodiment of such an absorbent article, an absorbent core is provided at a predetermined position between a cover sheet and a backsheet. From the viewpoint of achieving a favorable ratio between an absorbing amount for the absorbent core and an absorption rate, basically, an absorbent core layer comprising: superabsorbent polymers (so-called SAPs) excellent in the absorbent amount but inferior in the absorption rate; However, pulp fibers that are inferior in the amount of absorbent are superior in their absorption rate; and the same. In recent years, attempts have been made to make the absorbent core layer thinner to thin the absorbent core, and for this purpose, it has been proposed to reduce the amount of pulp fibers and to increase the content of superabsorbent polymers.

However, as the proportion of the superabsorbent polymers is increased, a peculiar grainy feeling by the superabsorbent polymers becomes noticeable, which leads to another problem that the wearer of the absorbent articles feels an increased foreign body feeling. Therefore, there is a difficulty in reducing the amount of pulp fiber and increasing the proportion of superabsorbent polymers. It should be noted that, for example, to improve the texture of the absorbent core, foam was used as the absorbent core layer, for example, as described in Patent Document 1 below. However, in the general cases, the strength (compression hardness of foam) is relatively high, the elasticity is also high, the stimulus (resistance moment) on the skin is too strong, and therefore the wearer feels much more likely to have a foreign body sensation.

• Patent Document 1: Japanese Unexamined Patent Application (PCT Application Publication), Publication No. H10-512168 ,

Summary of the invention

As described above, when using a low-pulp fiber absorbent material and higher proportion of superabsorbent polymers on the skin of the body, a foreign body feeling produced by the superabsorbent polymers is immediately obtained. In other words, the wearer feels the foreign body feeling on the skin at the contact with the topsheet, and in addition, the wearer feels the foreign body feeling on a non-skin contacting side caused by the superabsorbent polymers particularly on his or her inner thigh areas. More specifically, once the absorbent core is worn in the vicinity of the crotch region, the wearer may feel a foreign body sensation caused by the superabsorbent polymers in the skin non-contacting portion of the absorbent core on the inner thigh areas. On the other hand, for example, in the cases where a person hugs a child wearing a disposable diaper as an absorbent article, a hand of the person hugging the child (for example, a caregiver) will touch an outside of the disposable diaper and it For example, a foreign body sensation caused by the superabsorbent polymers will similarly be felt by this person. This leads to a deterioration in the texture of the disposable diapers and the product image, which can have a negative impact on the buying behavior of those who buy these products. In addition, such a diaper will give the impression of a hugging person (nurse) that a comparable stimulus is also felt on the skin of the wearer. Consequently, the hugging person has a negative impression such that he / she may not put on the diaper with a secure feeling.

The present inventors have obtained the present invention by the knowledge that by disposing entangled crimped fibers having a predetermined void content on both sides of an absorbent core layer, a foreign body feeling of both a wearer and a hugging person can be eliminated. In particular, the present invention provides the following.

A first aspect of the present invention provides an absorbent article comprising: a backsheet; an absorbent core applied to the backsheet in which the absorbent core comprises an absorbent layer and liquid-permeable layers disposed on both sides thereof, the absorbent core layer comprising a superabsorbent polymer having a basis weight of 50 g / m ² or more and pulp fibers having a basis weight of 50 g / m ² or less and each of the liquid-permeable layers applied on both sides is provided with entangled, crimped fibers having a void fraction ranging from 93.5% up to and including 99.9%.

A second aspect of the present invention relates to an absorbent article according to the first aspect of the present invention, wherein the superabsorbent polymers are spherical particles or agglomerated secondary particles having a form of agglomerated spherical primary particles.

A third aspect of the present invention relating to an absorbent article according to the described first aspect of the invention relates to the fact that the superabsorbent polymers contain more than 80% of superabsorbent polymers having a particle diameter of 200 μm-500 μm, based on the total weight of the superabsorbent polymers.

A fourth aspect of the present invention regarding an absorbent article as described in any of the absorbent articles described in any one of the first to third aspects of the present invention, wherein the absorbent article is a disposable diaper and the liquid-permeable layers are disposed on both sides, refers to an inner liquid-permeable article A layer disposed toward the wearer's side at a position corresponding to the crotch area and puffing area of the wearer, and an outer liquid-permeable layer formed on the opposite side of the wearer at a location corresponding to the buttocks of the wearer is.

A fifth aspect of the present invention relates to the absorbent article formed according to the fourth aspect of the present invention, wherein the inner liquid-permeable layer is also disposed at a position corresponding to the abdomen portion of the wearer.

A sixth of aspects of the present invention relates to the absorbent article formed according to any one of the first to fifth aspects of the present invention, wherein a thickness of the absorbent core layer is made thinner than a thickness of the inner liquid-permeable layer, the thickness being measured below a load of 35 g / cm ² and the thickness of the absorbent core layer is made thinner than the thickness of the outer liquid-permeable layer.

According to the present invention, the foreign body feeling that a wearer feels caused by the superabsorbent polymers can be reduced. Further, the foreign body feeling caused by the superabsorbent polymers also to a person hugging the wearer can be reduced, and further, a feeling of safety to the person who lets the wearer wear a disposable diaper.

Brief description of the drawings

1 Fig. 10 is a front view of a disposable diaper according to an embodiment of the present invention;

2 Fig. 10 is a plan view of a disposable diaper according to an embodiment of the present invention;

3 is a sectional view along the section line II, as in 2 shown;

4A is an enlarged view of crimped fibers;

4B is an enlarged view of a crimped fiber;

5 Fig. 10 is a plan view of a disposable diaper according to another embodiment of the present invention; and

6 is a sectional view taken along the line II-II 5 ,

Detailed description of the invention

Although the present invention will be described below in detail, the invention is in no way limited to the following embodiment, and the present invention may be construed as making suitable modifications without departing from the scope of the invention.

overall structure

1 shows a front view of a disposable diaper as an example of an absorbent article according to the present invention; 2 is a unfolded view 1 ; 3 is a cross-sectional view taken along the line II 2 ; and 4 is an enlarged view of crimped fibers.

As in 1 - 3 includes a disposable diaper 50 following: an upper layer 51 which is liquid pervious and which is disposed on the skin contacting side of the wearer; a rear position 53 which is liquid-impermeable and which is disposed on a non-skin-contacting side of the wearer; an absorbent core 52 that sandwiched between the top layer 51 and the rear layer 53 is arranged, in which the rear layer 53 and the top layer 51 around the circumference of the absorbent core 52 connected to each other. The disposable diaper 50 is designed in a trouser shape (pants) with a front part 55 and a back part 56 where the diaper has a front waist area 57 as edge portion of the front part 55 trains and a back waist area 58 as edge portion of the back part 56 formed. In addition, the unfolded disposable diaper has a rectangular shape, the cutouts 59 which are formed as cutouts in a substantially U-shaped shape inward in a width direction WD in a substantially central portion on both sides along a longitudinal direction LD of the disposable diaper. If the front part 55 and the back part 56 are connected in a trouser shape (pantyhose shape) form the recesses 59 openings 60 for the legs off. Next are the front part 55 and the back part 56 so joined together that a waist opening 61 is trained.

It should be noted that the absorbent article according to the present invention is not limited to a so-called disposable diaper pants type as in the present embodiment, but also to embodiments such as disposable diapers which can be stuck together, sanitary napkins, panty liners, a urine absorbent pad, and the like Application finds.

The layered structure in the vicinity of the absorbent core

The following is the positional structure near the absorbent core 52 a disposable diaper 50 with reference to the sectional view according to the line II, as in 3 shown.

The absorbent core 52 that sandwiched between the backsheet 53 and the top layer 51 is arranged, is formed by an absorbent core layer 521 and liquid-permeable layers 522 and 523 on both sides of the absorbent core layer 521 are arranged. The liquid-permeable layers 522 and 523 include the inner liquid-permeable layer 522 disposed on the skin-contacting side of the wearer and the outer liquid-permeable layer 523 which is disposed on a side facing away from the wearer (a non-skin contacting side). According to the present embodiment, the liquid-permeable layers 522 and 523 the substantially same shape as the absorbent core layer 521 on, as in the plan view in 2 recognizable, wherein all layers are laminated in a three-layer structure in the order of the inner liquid-permeable layer 522 , the absorbent core layer 521 and the outer liquid-permeable layer 523 , The rear position 53 For example, it may be formed as a gas-permeable PE layer (polyethylene resin), a liquid impermeable or hydrophobic nonwoven fabric, a laminated material of such a nonwoven fabric or the like. Advantageous is the top layer 51 is formed as a liquid pervious nonwoven layer such as a spunbond layer, a hot air-bonded nonwoven fabric, a point-bonded nonwoven fabric, a spun-lace nonwoven fabric, or a porous layer which is hydrophilic or has been treated to have them equipped with hydrophilic properties.

The absorbent core layer

The absorbent core layer 521 forms a central layer of the absorbent core 52 and comprises at least one superabsorbent polymer having a basis weight of 50 g / m ² or greater in a dry state and pulp fibers having a basis weight of 50 g / m ² or less in a dry state.

A preferred basis weight of the superabsorbent polymer is 70 g / m ² or more. A preferable basis weight of the pulp fibers is 30 g / m ² or less, and a more preferable basis weight thereof is zero (0). It is not advantageous if the basis weight has a value above 50 g / m ² , resulting in a thickening of the absorbent core layer 521 and such pulp fibers increase stiffness and reduce flexibility. It is also not advantageous if the basis weight of the superabsorbent polymers is less than 50 g / m ² , since this reduces the absorption capacity. As the superabsorbent polymer, a conventional and known material such as a polyacrylic acid-based material may be used, and in particular, such a material is not limited in any form. However, it is more advantageous for the superabsorbent polymer to use those particles of a solid form such as a spherical or berry form, since it can reduce the foreign body feeling as compared with particles of undetermined shape obtained by crushing. As an example of particles having a solid form including agglomerated particles will be referenced to particles disclosed in Japanese Unexamined Patent Application, Publication Number JP 2007-123188 (Translation of the PCT application WO 2007/123188 Advantageously, there are used secondary particles having a diameter of 200 μm-500 μm, which are obtained by agglutination of spherical primary particles of 30 μm-130 μm, whereby the grainy feeling and the foreign body feeling, which originate from the superabsorbent polymers, are used. can be reduced, even if the amount of pulp fiber, as described above, is low.

In the present embodiment, it is further preferable that the superabsorbent polymers include more than 80% of a superabsorbent polymer having a particle size (diameter) of 200 μm-500 μm based on the total weight of the superabsorbent polymer. This prevents the superabsorbent polymers from migrating to the skin of the wearer and consequently reduces the foreign body sensation that occurs due to the presence of superabsorbent polymers.

Conventionally well-known pulp fibers, such as granular pulp fibers, can be used as pulp fibers, the use of the pulp fiber being particularly not limited to these. It should be noted that fibers, such as fabric fibers, may be used in addition to the pulp fibers. More specifically, the absorbent core layer 521 of tissue or the like, with the pulp fibers and the superabsorbent polymers being mixed.

The absorbent core layer 521 According to the present invention has a light and thin construction, since the basis weight per unit area of superabsorbent polymers is greater than the basis weight per unit area of the pulp fibers. Conversely, as described above, this leads to a foreign body feeling caused by the particle-shaped superabsorbent polymers felt by the wearer. In view of this point, the present invention reduces the foreign body feeling by virtue of the fact that the liquid-permeable layers 522 and 523 on both sides around the superabsorbent core layer 521 are arranged.

The liquid-permeable layers

Each of the liquid-permeable layers 522 and 523 on both sides of the absorbent core layer 521 are arranged, provide an aggregate of crimped fibers 70 with a pore rate of between 93.5% to 99.9% inclusive, and more specifically, this means that the layers of crimped fibers 70 are formed, which are irregular or regularly involved with each other.

As in 4B shown is each of the crimped fibers 70 by shrinking a fiber 71 formed with a length dimension a in a shape, such as a three-dimensional helical shape with a length b. The force required to obtain the length dimension b to the length dimension a in a fiber longitudinal direction is extremely small, and the elasticity in one direction with respect to the outside diameter d of a crimped fiber shows an extremely low coefficient of elasticity. In other words, the external force required to compress the outer diameter d of the crimped fiber is small, so that the ability to return to the original state of the crimped fiber having the outer diameter d is excellent when no force is applied.

Therefore, in the case that the fiber longitudinal direction along the surface (the liquid-absorbing side) of the absorbent core layer 521 and the crimped outer diameter d is oriented in a thickness direction TD from the surface when the disposable diaper 50 is curved in a length direction LD or in a width direction WD, the liquid-permeable layers 522 and 523 the disposable diaper to be bent 50 adjust and the liquid-permeable layers 522 and 523 do not experience excessive restoring force to the disposable diaper 50 to return to a flat state overall. In addition, if the top layer 51 is compressed by the liquid-receiving side, the liquid-permeable layers 522 and 523 compressed and deformed in its thickness direction TD, and the cover layer 51 will probably adapt and adhere to the shape of the body.

In addition, since the crimped outer diameter d is aligned in the thickness direction TD, the crimped portions of the fibers ensure rapid penetration of the body fluid through the upper layer 51 to the absorbent core layer 521 , In addition, the liquid-permeable layers 522 and 523 a high pore rate and consequently these are able to quickly transfer body fluid into the absorbent core layer 521 penetrates even if the crimped fibers are formed of hydrophobic resin without hydrophilic properties. For example, the above-mentioned functions with respect to the cross-sectional shape of the crimped fibers 70 Preferably, the width may be greater than the thickness dimension, wherein the thickness dimension is preferably 10 μm-100 μm, and further wherein the width dimension is preferably 10 μm-500 μm, and further wherein crimped outer diameter d of the crimped fibers, without an external force acting, preferably between 0.3 mm-20 mm.

A method to the crimped fibers 70 to intertwine, for example, is in 4A wherein two melt flow rate (MFR) resin layers are coextruded, that is, a low melt index (MFR) resin layer having a high expansibility and a high melt flow rate (MFR) layer having no Expansibility is coextruded into the shape of a laminated film, which are then softened to a temperature between 80 ° and 150 ° below the melting point and uniaxially stretched in a flow direction of the film to be aligned in the flow direction. Subsequently, the film is cut in a direction x by means of a fiberizing machine and cut into separate fibers, with scattered dots 71 partially retained. Due to the difference in melt flow rate (MFR) between the front side and the back side, ripples are formed in the separated fibers, and it is thereby possible to make the liquid-permeable layers 522 and 523 which are network-like and interconnected at connection points 71 are connected. In addition, a cavity with a predetermined pore rate between the crimped fibers 70 educated.

In addition, another method may be employed in which thermoplastic long and pre-crimped fibers are arranged in a matrix at a constant pitch (for example, at a pitch of 5 mm-50 mm) and crossover portions (joints) of the crimped fibers by thermal welding welded together to form a net-like structure. For example, to curl the elongated fibers, one of the following methods can be used. A method for producing irregularities in cross-sectional areas of the fibers, which are then subjected to a thermal treatment or a treatment with hot water, so that the ripples form; by a method of embossing the fibers between heated gears; by a process in which thermal alignment of the fibers occurs through erroneous rotations of the fibers; or by a method in which fiber filaments are inserted into a chamber with a heated jet of air to thereby produce bends. Examples of Thermoplastic Fibers for Forming Crimped Fibers 70 include homopolymer PP (homo polypropylene), block PP (block polypropylene), high density polyethylene resins, and the like. The pore rate (the occupied volume per volume fraction) of the liquid permeable sheets 522 and 523 is preferably in the range of 93.5% to 99.9% inclusive. In the case where the pore rate is lower than 93.5%, the degree of crimping of the crimped fibers is reduced, so that the compressed and deformed volume is reduced, and thus the article is unlikely to conform to the wearer's body. In addition, the fluid permeability of a fluid passing through the upper layer 51 to the absorbent core layer 521 penetrates, degraded. Further, in the case where the pore rate exceeds 99.9%, the number of crimped fibers oriented in the thickness direction TD is between the topsheet 51 and the absorbent core layer 521 reduces and reduces the ability of the body fluid from the upper layer 51 to the absorbent core layer 521 is distracted, is thereby worsened.

The pore rate of the liquid-permeable layer 40 is calculated by the following formula. Pore rate (% = 1 - volume ratio) × 100

Here, the volume ratio is calculated by the following equation.
Volume ratio = density / specific fiber weight
(the calculation assumes that the specific fiber weight is 1 g / cm ³ )

In addition, the density is calculated according to 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 was determined by using a test pattern of constant size (for example, 10 cm × 10 cm), and the test sample was weighed. An average value of n = 10 measurements was taken to determine the average basis weight of the liquid-permeable layer. The thickness of the liquid-permeable layer was determined by means of an automated compression testing machine "KESFB-3A" manufactured by Kato Tech Co., Ltd. is produced, measured. The test sample is placed in the testing machine and the thickness is measured at a pressure on the sample as indicated at 0.5 g / cm ² . An average of 10 measurements (n = 10) was used to determine the thickness of the liquid-permeable layer.

The liquid-permeable layers formed with such a pore rate 522 and 523 be on both sides of the absorbent core layer 521 arranged, with the result the following effects are achieved. First, the inner liquid-permeable layer acts 522 , which is disposed on the side of the wearer, such as a cushion between the granular superabsorbent polymers and the skin, thereby reducing the foreign body feel for the wearer resulting from the superabsorbent polymers. On the other hand, since the outer liquid-permeable layer 523 which is located on the side opposite to the wearer, as well as the foreign body feeling reduces in the event that a person the carrier, which the disposable diaper 50 which is also derived from the superabsorbent polymers. As a result, the person who lets the wearer wear the disposable diaper gives a sense of security.

It should be noted that the body fluid once entrapped in the space within the crimped fibers is then gradually absorbed by the superabsorbent polymers. Thereby, the reduction of the absorbing amount and the absorption rate can be simultaneously lowered even if the absorbent core 52 contains only a small amount of pulp fibers. In other words, the space formed by the crimped fibers becomes on both sides, that is, on the skin-contacting side and the garment-facing side, by attaching the inner liquid-permeable layer 522 and the outer liquid-permeable layer 523 whereby the body fluid can be temporarily held in both layers and thereby the absorption efficiency of the superabsorbent polymers can be improved.

Moreover, in the present embodiment, in which the thickness is measured under a surface load of 35 g / cm ² , the thickness of the absorbent core layer is 521 advantageously thinner than the thickness of the inner liquid-permeable layer 522 and the thickness of the absorbent core layer 522 is advantageously thinner than the thickness of the outer liquid-permeable layer 523 , As a result, even in the case of an external force on the absorbent core 52 interacts and the absorbent core layer 521 thereby partially into the inner liquid-permeable layer 522 or outer liquid-permeable layer 523 dipped, the foreign body feeling from the absorbent core layer 521 likely to be kept away from the front or back.

Second embodiment

5 Fig. 11 is an unfolded view of a disposable diaper as another embodiment of the present invention; in 6 is a cross-sectional view taken along the line II-II 5 shown. The present embodiment differs from the above-mentioned embodiment in that the inner liquid-permeable layer 522a and the outer liquid-permeable layer 523a at different locations on the absorbent core layer 521 are attached. Especially with regard to the liquid-permeable layers which are on both sides of the absorbent core layer 521 are disposed, is the inner liquid-permeable layer 522a disposed on the wearer-facing side, disposed at a position corresponding to the crotch region and buttock region of the wearer, the outer liquid-permeable layer 523a which is arranged on the side facing away from the carrier, so arranged at a position corresponding to the position of the buttocks of the wearer. In particular, in the present embodiment, the outer liquid-permeable layer 523a smaller and, in particular, the inner liquid-permeable layer 522a larger than the outer liquid-permeable layer 523a formed with respect to the areas on which the liquid-permeable layers are arranged.

The foreign body feeling can be sufficiently reduced for the wearer by changing the positions of the arrangement of the liquid-permeable sheets inside and outside, for example, by arranging the inner liquid-permeable sheet 522a in an area where the load is carried, near the area around the crotch portion and the area of the buttocks. In addition, the outer liquid-permeable layer covers 523 the absorbent core layer 521 located near the area of the buttocks that is touched by the hand of a wearer, thereby reducing the foreign body sensation for the hugging person for someone who includes the wearer of the diaper.

By selectively arranging the crimped fibers, the liquid-permeable layers thus formed can reduce the foreign-body feeling in an acceptable manner in a region which may possibly cause a foreign-body feeling. Although preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiment described above and can be appropriately adjusted. For example, although the inner liquid pervious layer 522a is arranged in the aforementioned embodiment in the vicinity of the crotch area and the buttocks, these may be arranged in other areas and is not limited thereto. Preferably, in the case of a disposable diaper for men (Boys), the inner liquid-permeable layer in the region of the abdomen may be arranged. In this case, the foreign body feeling around the sex organ can be reduced and the body fluid temporarily stored, so that such a disposable diaper is suitable for boys and shows an improved absorption efficiency. The foreign body sensation in the abdominal area of the wearer can also be reduced.

LIST OF REFERENCE NUMBERS

50

disposable diaper

51

upper layer

52

absorbent core

521

absorbent core layer

522

liquid permeable layer (inner liquid permeable layer)

523

liquid permeable layer (outer liquid permeable layer)

522a

liquid permeable layer (inner liquid permeable layer)

523a

liquid permeable layer (outer liquid permeable layer)

53

rear position

55

front body

56

rear body

57

front waist region

58

back waist region

60

leg openings

61

waist opening

70

crimped fibers (crimped fibers)

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2012-130300 [0001]
• JP 10-512168 [0005]
• JP 2007-123188 [0029]
• WO 2007/123188 [0029]

Claims (6)

An absorbent article comprising a backsheet and an absorbent core disposed on the backsheet, the absorbent core comprising: an absorbent core layer and liquid pervious layers disposed on both sides of the absorbent core layer, the absorbent core layer comprising superabsorbent polymers having a basis weight of 50 g / m ² or more; Pulp fibers having a basis weight of 50 g / m ² or less and wherein each of the liquid-permeable layers disposed on one of the two sides is composed of interwoven crimped fibers whose pore rate is between 93.5% and 99.9% inclusive. Absorbent article according to claim 1, wherein the superabsorbent polymers are spherical particles or agglomerated secondary particles whose shape is formed from agglomerated spherical primary particles. Absorbent article according to claim 1, wherein the superabsorbent polymers comprise more than 80% of superabsorbent polymers having a particle diameter of 200 μm-500 μm based on the total weight of the superabsorbent polymers. Absorbent article according to any one of claims 1 to 3, wherein the absorbent article is a disposable diaper and wherein, with respect to the liquid-permeable layers disposed on both sides, an inner liquid-permeable layer is disposed on the wearer-facing side in a layer which conforms to the step and buttocks layer of the wearer and an outer liquid-permeable layer on a side facing away from the carrier in a position corresponding to the buttocks layer of the wearer, is arranged. The absorbent article according to claim 4, wherein the inner liquid-permeable layer is also disposed at a position corresponding to the abdominal area of the wearer. The absorbent article according to any one of claims 1 to 5, wherein a thickness of the absorbent core layer is thinner than a thickness of the inner liquid-permeable layer and the thickness of the absorbent core layer is thinner than the thickness of the outer liquid-permeable layer, the thickness being below a surface load of 35 g / cm ^{2 is} measured.

Images