WO2007077215A1

WO2007077215A1 - Multilayer absorbent core for an absorbent hygiene product and absorbent hygiene product containing said core

Info

Publication number: WO2007077215A1
Application number: PCT/EP2007/000021
Authority: WO
Inventors: Alvaro Garcia; Katja Lerner
Original assignee: Johnson & Johnson Gmbh
Priority date: 2006-01-04
Filing date: 2007-01-03
Publication date: 2007-07-12
Also published as: DE102006000779A1

Abstract

The invention relates to a multilayer absorbent core comprising a front and a back for an absorbent hygiene product. Said multilayer absorbent core comprises at least one first layer having a front and a back, containing a mixture from superabsorbent fibers, multi-component fibers and regenerated cellulose-based and/or polyester-based fibers, and at least one second layer having a front and a back, containing a mixture from multi-component fibers and superabsorbent fibers, the front or back of the first layer being adjacent to the back or front of the second layer. The invention also relates to an absorbent product for feminine hygiene, containing at least one absorbent core according to the invention.

Description

A multi-layered absorbent core for an absorbent sanitary article and a sanitary absorbent product containing said core

description

The present invention relates to a multi-layered absorbent core for a sanitary absorbent article and to personal care absorbent products, in particular feminine hygiene absorbent feminine hygiene products comprising at least one absorbent core of the invention.

The trend in sanitary napkins and panty liners is currently towards ever thinner products. Of course, a high absorption and retention capacity is required even of these very thin hygiene products despite the lower material usage. Moreover, one is generally unwilling to accept any loss in wearing comfort. Even very thin absorbent products are required to feel very soft on the skin and at the same time be very flexible in order to be able to adapt to the body shape even under heavy stress, so that leakage can be prevented in any situation.

Particular importance is attached to sanitary napkins and panty liners to the absorbent core. This determines significantly the thickness of the hygiene product as well as the absorption and retention behavior of the absorbent product.

EP 1 030 633 B1 deals with absorbent articles, such as panty liners and sanitary napkins, which conform well to the body and thus reduce the risk of Reduce leakage. The absorbent article according to EP 1 030 633 Bl is characterized by a bending resistance which is not greater than 100 g. The absorbent core is in this case composed of a so-called "high loft" material having a density of preferably less than 0.01 g / cm ^3. Preference is given, for example, to thermally bonded, kadierte polyester fiber webs having a basis weight of about 50 g / m ² In addition, wood pulp fibers, meltblown polymer fibers, regenerated cellulose fibers and superabsorbent materials are also suitable for the core Preferably blends of synthetic polymer fibers, cellulosic fibers and fibers of a superabsorbent, hydrogel-forming polymer are used according to EP 1 030 633 B. The superabsorbent hydrogel-forming polymer can These airlaid nonwovens may, for example, be solidified by means of needlepunching If EP 1 030 633 B1 discloses an absorbent core with a layered structure, this is the airlaid fabric described above. Fleece, that is underlaid with a layer of particles or fibers of a gel-forming polymer material. However, the absorbent article according to EP 1 030 633 B1 still always leaves something to be desired with regard to the wearing comfort, the softness and the leakage protection, in particular in the case of absorbent hygiene articles which are designed in very thin form.

It is an object of the present invention to provide an absorbent article which does not suffer from the drawbacks of the prior art and which is characterized in particular by a high degree of softness and flexibility combined with a very high absorption and retention capacity.

Accordingly, there has been found a multi-layer absorbent core having a front and a back side for a sanitary absorbent article comprising at least a first layer having a front and a back containing a blend of superabsorbent fibers, multicomponent fibers, and regenerated cellulose based fibers and / or Polyester fibers, and at least a second layer having a front and a back containing a mixture of multicomponent fibers and superabsorbent fibers, wherein the front or back of the first layer is adjacent to the back of the second layer.

According to a preferred embodiment it is provided that the first layer 20 to 45% by weight of fibers based on regenerated cellulose, 30 to 50 wt .-% multi-component fibers and 5 to 50 wt .-% superabsorbent fibers and / or that the second layer 40 to 80 wt .-% multi-component fibers and 20 to 60 wt .-% superabsorbent fibers.

Another embodiment of the invention provides for combining at least two of the above-described multilayer absorbent cores. In this case, the respective outer surfaces of the second layer of the first core and of the first layer of the second core, for example the back of the second layer and the front of the first layer, preferably rest against each other or at least in large part, i. with a common overlap area of more than 50%, adjacent.

In a further development, the absorbent core of the present invention further comprises at least a third layer having a front and a back containing a blend of superabsorbent fibers, regenerated cellulose fibers and multicomponent fibers at least partially disposed between the first and second layers ,

Here, it is preferred that the first layer 20 to 45 wt .-% fibers based on regenerated cellulose, 30 to 50 wt .-% multi-component fibers and 5 to 50 wt .-% superabsorbent fibers and / or that the second layer 40 to 80th Wt .-% multi-component fibers and 20 to 60 wt .-% superabsorbent fibers and / or that the third layer 10 to 60 wt .-% fibers based on regenerated cellulose, 30 to 50 wt .-% multi-component fibers and 10 to 40 wt. comprise% superabsorbent fibers. A further embodiment according to the invention provides for combining at least two of the multilayer absorbent cores described immediately above. Preferably, the respective outer surfaces of the second layer of the first core and the first layer of the second core, for example, the back of the second layer and the front of the first layer, at least partially abut each other or are at least in large part, ie with a common overlap area of more than 50%, adjacent.

The cores of the invention are preferably configured flat with opposite upper and lower sides. The peripheral edge regions can assume a multiplicity of different cross-sectional geometries. The thickness of the planar cores according to the invention can be varied within wide ranges. Very thin cores, e.g. with a thickness in the range of about 1 to 5 mm, can be realized as well as thicker or very thick cores in the range of 5 to 20 mm, which with thick as well as in particular very thin cores invention, the desired properties sought with the present invention , as a very good absorption and retention capacity with high flexibility, can be achieved. Moreover, in a further embodiment, the planar cores according to the invention have a longitudinal axis and a smaller dimensioned transverse axis which can be arranged perpendicular thereto. With the cores according to the invention are therefore very thin products for feminine hygiene such as sanitary napkins and pantyliner accessible that hardly apply to clothing, are comfortable to wear and at the same time offer a high fluid absorption capacity. Likewise, with thicker products a very good wearing comfort with good flexibility.

In this case it can be provided that the fibers based on regenerated cellulose, e.g. Modal, cupro, lyocell and in particular viscose fibers and / or that the polyester fibers polyethylene terephthalate fibers and / or that the multicomponent or multicomponent fibers bicomponent fibers, in particular

Polyethylene / polypropylene fibers. Natural cellulose fibers are obtained, for example, from so-called wood fiber pulp. Their preparation and processing is well known to those skilled in the art. The same applies to regenerated cellulose fibers. Suitable regenerated cellulose also includes cellulose acetate fibers. Lyocell fibers are regenerated cellulose fibers which are particularly environmentally friendly to produce. These fibers are obtained by extrusion of an aqueous tertiary amine N-oxide, for example N-methymorpholine N-oxide, dissolved cellulose into an aqueous coagulation bath by the solvent spinning method. For further details regarding the production process of lyocell fibers, see US 5,094,690. Lyocell fibers are more similar in their property profile to cotton fibers than rayon fibers. Lyocell fibers are characterized in particular by a high strength in the wet state. Lyocell fibers can be purchased, for example, from the companies Acordis Cellulosic Fiber under the trade name Tencel or the company Lenzing Fibers under the trade name Lenzing Lyocell.

Suitable multicomponent fibers include, for. B. bi- and tricomponent fibers. By bicomponent fibers is generally understood those fibers in which two different polymers are present in non-homogeneous form next to each other. This may mean in one embodiment that two polymers are arranged side by side in a fiber strand side by side. In a further embodiment, a first polymer may form the core which is enveloped by a second polymer. In addition, it is possible for a first polymer to be completely enveloped by a second polymer to form individual islands in the second polymer. Suitable bicomponent fibers are generally composed of two thermoplastic polymers, for example polyolefins and polyamides, polyolefins and polyesters or polyamides and polyesters. Particularly suitable for the present fiber webs z. B. bicomponent fibers based on polyolefins and polyesters, in particular comprising the combinations polyethylene / polyethylene terephthalate and polypropylene / polyethylene terephthalate. Furthermore, it is provided in a further embodiment that the bicomponent fiber is a polyethylene / polypropylene fiber, a polypropylene / polyethylene terephthalate fiber, a Polyethylene / polyethylene terephthalate fiber, a polyethylene terephthalate / co-polyethylene terephthalate fiber or any mixture thereof. Bi-component fibers based on polyethylene and polypropylene are particularly preferred.

Furthermore, particularly preferred are absorbent cores in which the first, second and / or third layers comprise layers produced using the air-through-bonding technique.

Also of advantage are those embodiments in which the first layer has a basis weight in the range from 10 to 90 g / m ² and / or the second layer has a basis weight in the range from 10 to 90 g / m ² and / or the third layer has a basis weight in the range of 10 to 90 g / m ² .

Particularly preferred absorbent cores are characterized in that the fluid retention capacity of the core is at least twelve times the dry weight thereof.

In terms of retention capacity, the absorbent cores of the present invention are preferably capable of retaining at least 20% by weight of total absorbed amount of fluid in the absorbent core when pressure is applied.

In preferred embodiments, the absorbent core has a flexural stiffness, as determined by the circular bonding test, of not more than 100 g.

Very thin absorbent cores are erfϊndungsgemäß also accessible by calendering them at least partially.

It has also proved to be advantageous to mix the fibers of the first, second and / or third layer of the absorbent core by means of carding. Accordingly, the first, second and / or third layer at least partially a fiber mixture obtainable by carding.

According to a further aspect of the present invention, there are provided absorbent personal care products, in particular feminine hygiene absorbent products, such as panty liners and sanitary napkins, which comprise at least one absorbent core according to the invention. These absorbent products generally have at least one liquid-permeable cover layer and at least one liquid-impermeable barrier layer, between which at least one absorbent core according to the invention is provided.

Accordingly, in a further development according to the invention, the absorbent hygiene product comprises at least two abutting absorbent cores according to the invention, the front or back side of the first core being adjacent to the rear or front side of the second core.

The multilayer absorbent cores according to the invention are distinguished from comparable systems by a good absorption capacity and an increased retention capacity, in particular under pressure. This applies in particular to systems with higher basis weights. In addition, a considerably increased flexibility is achieved with the structures according to the invention. Above all, the absorbent cores of the invention are also distinguished from comparable systems produced by means of airlaid technology.

The advantages and properties of the absorbent core according to the invention are explained in more detail below by means of examples. The Examples II and IV according to the invention listed below can essentially be obtained by superimposing in each case two absorbent multilayer structures according to Example I or according to Example III, forming an absorbent multilayer core, and have been joined together. The composition of the absorbent cores according to the invention is shown in Table 1 below.

Table 1

^!) the viscose fiber is Lenzing viscose fibers from Lenzing,

the bicomponent fiber (Bico) is fiber ES-Cure from FiberVisions, the superabsorbent fiber (SAF) is the fiber "super absorbent fiber 102" from OASIS.

The fibers of the first and second layers according to Example I and the first, second and third layers according to Example III were each homogeneously mixed using the carding technique. The individual layers were consolidated by means of air-through-bonding technique, and obtained the multilayer composite by calendering. In the same way, the double structures of the absorbent cores according to Examples II and IV were obtained by overlaying and bonding the multilayer systems according to Examples I and III, respectively, by means of calendering.

In the following Table 2 the absorption and retention behavior of the absorption layer structures according to the invention is reproduced and compared with an absorbent core according to the prior art.

Table 2

³⁾ The multi-layered absorbent cores were soaked in water for two minutes and then placed on a horizontally arranged drip grid for 10 minutes.

⁴⁾ The comparative absorbent structure is the commercially available structure Concert MH 102 (80 g / m ² ).

As the foregoing examples show, the multi-layered absorbent cores of the invention are characterized by a very advantageous absorbency, although they have a substantially lower basis weight than conventional absorbent core structures. Without wishing to be bound by any theory, it is presently believed that the absorbent structures of the present invention do not exhibit gelation-related flow path blockages.

It is also of particular advantage that the advantageous properties of the absorbent cores according to the invention can also be achieved with very flexible structures with regard to absorption and retention capacity. For example, the absorbent cores according to Examples I and II have a bending resistance according to the Circular Bending Test of about 8 and 10 g, respectively. In contrast, the absorbent core according to the comparative example has a bending resistance according to the circular bending test of about 60 g.

The Circular Bending Test is generally performed with an Instron 4411, Series IX, with a 6.35 mm diameter plunger and a spherical attachment with a needle point 0.8 mm in diameter. The ram has a travel distance of 16.35 mm and is moved up and down at a speed of 500 mm / min. The layer structures to be examined had a size of 38 × 38 mm ² and were conditioned for 24 hours at 20 ° C. ± 2 ° C. and 65% ± 2% atmospheric humidity before the start of the test. The test bodies were polished over the opening Metal plate whose circular opening at the bottom of the plate had a diameter of 18.75 mm and at the top of 28.25 mm. The edge of this circular opening was inclined by 45 °. Maximum flexural stiffness was measured while the plunger deflected the 6.35 mm test product downwards. The reproduced values represent the arithmetic mean of a total of ten individual measurements.

The features of the invention disclosed in the foregoing description and in the claims may be essential both individually and in any combination for the realization of the invention in its various embodiments.

Claims

claims

A multi-layered absorbent core having a front and a back for an absorbent sanitary article comprising at least a first layer having a front and a back containing a blend of superabsorbent fibers, multicomponent fibers, and regenerated cellulose and / or polyester fiber based fibers; and at least one second layer having a front and a back containing a mixture of multicomponent fibers and superabsorbent fibers, wherein the front or back of the first layer is adjacent to the back of the second layer.

2. Absorbent core according to claim 1, characterized in that the first layer 20 to 45 wt .-% fibers based on regenerated cellulose, 30 to 50 wt .-% multi-component fibers and 5 to 50 wt .-% superabsorbent fibers and / or the second layer comprises 40 to 80% by weight of multicomponent fibers and 20 to 60% by weight of superabsorbent fibers.

The absorbent core of claim 1 or 2, further comprising at least a third layer having a front and a back containing a blend of superabsorbent fibers, regenerated cellulose fibers and multicomponent fibers at least partially interposed between the first and second layers is appropriate.

4. Absorbent core according to claim 3, characterized in that the first layer 20 to 45 wt .-% fibers based on regenerated cellulose, 30 to 50 wt .-% multi-component fibers and 5 to 50 wt .-% superabsorbent fibers and / or the second layer contains 40 to 80% by weight Multi-component fibers and 20 to 60 wt.% Superabsorbent fibers, and / or the third layer 10 to 60 wt.% Of regenerated cellulose fibers, 30 to 50 wt.% Of multicomponent fibers and 10 to 40 wt.% Of superabsorbent fibers includes.

5. Absorbent core according to one of the preceding claims, characterized in that the fibers based on regenerated cellulose modal, cupro, lyocell and in particular viscose fibers and / or that the polyester fibers polyethylene terephthalate fibers and / or that the multicomponent fibers bicomponent fibers, in particular Polyethylene / polypropylene fibers.

6. Absorbent core according to one of the preceding claims, characterized in that the first, second and / or third layer comprise layers produced using the air-through-bonding technique.

7. Absorbent core according to one of the preceding claims, characterized in that the first layer has a basis weight in the range of 10 to 90 g / m ² and / or the second layer has a basis weight in the range of 10 to 90 g / m ² and / or the third layer comprises a basis weight in the range of 10 to 90 g / m ² .

Absorbent core according to one of the preceding claims, characterized in that the liquid retention capacity of the core comprises at least 12 times the dry weight thereof.

Absorbent core according to one of the preceding claims, characterized in that, when pressure is applied, at least 20% by weight of absorbed total amount of liquid remain in the absorbent core.

10. Absorbent core according to one of the preceding claims, characterized by a flexural rigidity, determined by the "circular bonding test" of not more than 100 g.

11. Absorbent core according to one of the preceding claims, characterized in that it comprises at least one calendered region.

12. Absorbent core according to one of the preceding claims, characterized in that the first, second and / or third layer comprises, at least in regions, a fiber mixture obtainable by means of carding.

Absorbent sanitary product, in particular feminine hygiene absorbent product, comprising at least one absorbent core according to one of the preceding claims.

14. An absorbent article according to claim 13, characterized by at least two abutting absorbent cores according to one of claims 1 to 12, wherein the front or back side of the first core is adjacent to the rear or front side of the second core.

Absorbent product according to claim 13 or 14, comprising a sanitary napkin or panty liner.

16. An absorbent product according to any one of claims 13 to 15, comprising at least one liquid-permeable cover layer, at least one absorbent core according to any one of claims 1 to 12, and at least one liquid-impermeable barrier layer.