DE102006000782A1 - Multi-layer non-woven composite for absorptions and retention ability e.g. absorbing hygiene products, has first non-woven fabric layer, which has mixture of cellulose-based fabrics and thermoplastic fabrics - Google Patents

Abstract

Multi-layer non-woven composite, has a first non-woven fabric layer (2), which has a mixture of cellulose-based fabrics and thermoplastic fibers, a second layer (4), which has a super absorbing particle and super absorbing fibers. Multi-layer non-woven composite, has a third non-woven fabric, which has a partial hydrophobic spin bound fabrics. An independent claim is also included for the absorbing article.

Description

The The present invention relates to an absorbent multilayer composite nonwoven fabric and absorbent articles containing this composite nonwoven.

Regarding Comfort and absorption and retention capacity are These days, increasing demands are placed on absorbent hygiene products. At the same time, the trend is towards ever thinner absorbent products, for example, in the area of panty liners and sanitary napkins. The thinner one such hygiene product is less pronounced in the In general, however, its absorbency. In particular, the absorption capacity affected by such products. Nevertheless, at least fairly To obtain satisfactory absorption properties is included so thin Special care should be taken to ensure that the absorbent materials preferably equally distributed present and during the production, storage or use their intended Keep position.

In For example, US 2002/0034912 A1 discloses a fabric laminate comprising an upper and a lower fabric web and one between them arranged filling layer from a non-thermoplastic holey material, too may contain superabsorbent substances described. At the outer fabric tracks it is preferably nonwoven material made of thermoplastic Fibers, also comprising bicomponent fibers. In another embodiment are the outer fabric webs each of several layers of meltblown and / or spunbonded Built up fibers. For example, so-called MS or SMS systems are used in question. In the intermediate layer z. B. superabsorbent Particles or superabsorbent fibers, optionally mixed with an adhesive, be stored. Obtained according to US 2002/0034912 A1 a solid laminate composite also in that the thermoplastic materials the outer two Layers in the area of the holes the intermediate layer contact each other and heat-connected become. In this way you can use adjacent layers, which do not necessarily have to be thermally compatible without to rely on the use of adhesive materials.

The WO 98/47456 discloses an absorbent nonwoven web comprising a fiber layer obtained by the airlaying technique, which has more than 70% of fibers with a length below 12 mm. As a binder can thermoplastic fibers, in particular bicomponent fibers with a Polyester core and a polyolefin shell be present. A solidification the nonwoven fabric according to WO 98/47466 can by applying the so-called Hydroentengelment process brought become. The aforementioned nonwoven materials are suitable for example the production of tampons. Suitable short fibers also include Cellulose fibers and regenerated cellulose fibers.

Of the WO 95/03019 discloses an absorbent intermediate, comprising two outer nonwoven webs, which are available by means of airlaying technology, and one between them Layered layer containing superabsorbent particles or fibers with thermoplastic materials as thermal Adhesives are mixed. With the composite structure of WO 95/03019 should the absorbent particles in the liner at a desired Let it fix position without this absorbing material is solidified in this case. Because it has been found that superabsorbent Materials only show their maximum absorbency when they in a loose, loose state in an absorbent article available.

The DE 101 23 099 C1 describes a method for producing a multi-layer absorbent article whose outer panels are produced in particular by means of the airlaying technique and in which it is also possible to resort to superabsorbent polymers for the intermediate layer. The method according to the DE 101 23 099 C1 is characterized in that a first continuously applied intermediate absorbent layer is removed in parts from the first, outer layer again, wherein a transverse seal is applied in strips between the Saugmittelschichten arranged separately. In this way, absorbent materials can be fixed in an intermediate layer, without the absorbent material is solidified in the manufacturing process.

From WO 01/39880 an absorbent intermediate emerges which has a liquid-permeable upper layer, a lower layer and an intermediate layer containing e.g. For example, a blend of superabsorbent fibers and thermoplastic fibers. The thermoplastic fibers of the intermediate layer can be used to thermally bond the outer layers. Optionally, the outer layers can also be connected with the help of adhesive strips. While the top outer layer is a nonwoven fibrous web obtained by airlaying technology, including, for example, cellulosic fibers, polypropylene fibers, polyethylene fibers, and / or polyester fibers, the bottom layer may be formed inter alia by a so-called SM or SMS system. Such intermediates find z. B. as absorbent cores of absorbent hygiene products use. With the multi-layer system of WO 01/39880 an efficient leakage prevention and fluid retention is to be achieved without relying on additional outer layers.

nevertheless there is still a lack of absorbent hygiene products that sufficient are flexible and accordingly readily to any movement of the wearer or the wearer without changing their absorption and retention properties impaired to become.

Of the The present invention was therefore based on the object, an absorbent Material available to provide, which is characterized by a high wearing comfort a very soft surface feel at one nevertheless very thin-layered structure mediated and under static as well as dynamic conditions has an excellent absorption and retention capacity.

Accordingly, became a multilayer composite fleece found comprising at least a first A nonwoven fabric layer comprising a blend of cellulosic fibers and thermoplastic fibers, at least one second layer superabsorbent particles and / or superabsorbent fibers, and at least one third nonwoven fibrous layer comprising at least partially hydrophobic spunbond fibers.

there may be preferably provided that the thermoplastic fibers the first layer of multicomponent fibers, in particular bicomponent fibers, include.

Further is provided in a further embodiment that the bicomponent fiber 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.

suitable Multicomponent fibers include, for. B. bi- and tricomponent fibers. By bicomponent fibers is generally meant such fibers, in which two different polymers in non-homogeneous form coexist. This may be in one embodiment mean two polymers side by side in one Fiber strand are arranged. In a further embodiment For example, a first polymer may form the core that is enveloped by a second polymer. Furthermore Is it possible, that a first polymer is complete of a second polymer to form individual islands in the second polymer wrapped becomes. Suitable bicomponent fibers usually combine from two thermoplastic polymers, for example polyolefins and Polyamides, polyolefins and polyesters or polyamides and polyesters. Especially suitable for the present fiber webs are z. B. bicomponent fibers on the Basis of polyolefins and polyesters, in particular comprising the Combinations polyethylene / polyethylene terephthalate and polypropylene / polyethylene terephthalate. Furthermore, bicomponent fibers are based on polyethylene and Polypropylene suitable.

Further, in the present case, so-called "spiral crimp" fibers are to be subsumed under suitable bicomponent fibers. "Spiral crimp" fibers are generally obtained by using a thermoplastic polymer which is used in two different viscosities. Exemplary are the "spiral crimp" polyester fibers H18Y from Unitica Ltd., Japan, and 7-HCS from Sum Young, South Korea The different viscosities of the two polyester polymers used are generally attributed to the use of polyesters with different molecular weight. "Spiral crimp" fibers are usually characterized by a helical configuration. For more details on "Spiral Crimp" fibers, see the US 5,723,215 directed.

Of Furthermore, it can be provided that fibers based on cellulose natural Cellulose fibers and / or regenerated cellulose fibers, in particular Viscose, Modal, Cupro and / or Lyocell 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 includes, among others, 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-methylmorpholine 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 directed. 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.

The proportions of the cellulosic fibers and the thermoplastic fibers can be widely varied for the first nonwoven fabric layer be varied. For example, in a preferred embodiment, the cellulosic fiber may be present in amounts of from 30 to 70 percent by weight, based on the weight of the first nonwoven fibrous layer. Similarly, the thermoplastic fibers may be incorporated into the first nonwoven fibrous layer in amounts of from 30 to 70 percent by weight.

The thermoplastic fibers, powders and granules can be, for example, polyolefins, such as polyethylene or polypropylene, polyamides, polyacetals, polyesters, Polyacrylates and polymethacrylates include. The thermoplastic Material represents the binder, with the help of a solidification of the fibrous web is achieved. Particularly suitable thermoplastic Fibers include polyolefin fibers, polyester fibers and polyamide fibers.

One Another aspect of the invention provides that the second layer furthermore thermoplastic fibers, thermoplastic powders and / or thermoplastic granules and / or zeolites comprises or include. It is also particularly preferred that the third layer at least an SM, SMS and / or SMMS laminate.

at SM, SMS and / or SMMS laminates are those that at least one layer or layer comprising spunbond synthetic Fibers, and at least one layer or layer comprising meltblown synthetic fibers, included. In the aforementioned laminate structures Thus, layers containing melt-blown fiber sand are advantageously over or under layers containing spunbond fibers.

For example becomes in a manufacturing process for a SMS laminate first a Fiber layer of spunbonded fibers on a treadmill by means of Extrusion applied. The spunbond fibers of this layer are very long and can be designed as so-called endless fibers. Spunbond fibers are generally initially stretched after extrusion, before being applied to one Pad to be placed for the purpose of forming a nonwoven layer. Onto this spunbonded nonwoven layer are then meltblown fibers applied to form a second layer of nonwoven fabric. Meltblown Fibers usually over a smaller diameter than spunbond fibers. In addition are these fibers shorter as spunbond fibers, i. they are not as continuous Fibers before. On the nonwoven layer of meltblown fibers finally becomes again a layer as described above, applied. The obtained SMS multilayer structure can subsequently still undergo a calendering step, even to a connection between the individual layers.

Suitable starting materials for the production of meltblown and spunbonded fibers are thermoplastic polymers and mixtures thereof, in particular polyolefins. Polypropylene is a particularly preferred starting material for spunbonded and meltblown nonwoven fabric layers. The nonwoven laminates described above and their preparation can be found, inter alia, in the patents US 4,041,203 . US 5,169,706 and US 4,374,888 described.

The Multilayer nonwoven laminates can to increase structural resistance be bound together in a known manner. suitable Tying methods provide hydroentangling, needling, ultrasonic bonding, Adhesive binding and thermal bonding dar. Thermally, the Multi-layer nonwoven laminates z. B. By passing through the rollers of a Calendering machine can be connected. Here is at least one heated the rollers of the calender. While passing through the Calendering machine, the multi-layer nonwoven laminate is both pressure as well as subjected to heat.

Especially it is also preferred the third layer comprises at least one SM, SMS and / or SMMS laminate.

In a further development comprises the composite nonwoven fabric according to the invention at least one fourth nonwoven fibrous layer comprising at least partially hydrophobic spunbonded fibers between the first and second Layer is arranged.

moreover it can be provided that at least a fifth layer comprising superabsorbent Particles and / or superabsorbent fibers interposed between the first and fourth layer is arranged.

From It is also particularly advantageous that the first and fourth layers and / or the first and the third layer in regions with each other glued and / or welded, in particular thermowelded, are.

suitable Adhesive and / or adhesive to adjacent nonwoven fabric layers with each other are well known to those skilled in the art. At the preferred Variant of thermal welding becomes exploited that by applying energy, in particular Thermal energy, the thermoplastic fibers of the first nonwoven fabric layer and the spunbonded fibers of the third or fourth nonwoven fibrous layer at least partially melted. In particular, by application of pressure these melts are brought into contact with each other, so that they cool down form a close bond.

According to the invention, it is further provided that the first layer has a basis weight in the range from 15 to 100 g / m ² , in particular from 25 to 60 g / m ² , and / or the second and / or the fifth layer has a basis weight in the region of fifteen to 80 g / m ² , in particular in the range of 25 to 40 g / m ² , and / or the third and / or the fourth layer has a basis weight in the range of 5 to 60 g / m ² , in particular in the range from 15 to 30 g / m ² , or have.

The interconnected individual nonwoven layers can be particularly due to the selected layer materials and Layer structures each run very thin, which in turn is a very thin Composite nonwoven result. The thickness of the composite nonwoven fabric according to the invention can be varied within a wide range. Very thin composite nonwovens, z. B. with a thickness in the range of about 1 to 5 mm can also be realized like thicker or very thick composite nonwovens in the range of about 5 to 20 mm, with thick and in particular very thin composite non-wovens according to the invention the advantageous properties sought with the present invention, how very good absorption and retention capacity at the same time high Flexibility, achieve to let.

A another embodiment The invention is characterized in that the third and / or fourth Layer further natural and / or manipulated natural ones Fibers include or include.

suitable natural Fiber materials include silk, keratin and cellulose. Among these materials are cotton, wool, silk, linen, sisal, hemp, rami, flax and jute fibers particularly suitable. As so-called manipulated natural Fibers are especially regenerated cellulose fibers, such as. Viscose, cupro, modal and lyocell fibers, as well as polylactide and polyalginate fibers.

at Very particularly preferred composite nonwovens is provided that the first and / or fourth layer using the air-through-bonding Technique and / or the calendering technique is available or are.

The Through airbonding technique is generally known to those skilled in the art. This is a gentle procedure for treatment of fibers with heated or heated air, causing it over a softening or melting of the fibers for bond formation comes. Accordingly, in the through-air-bonding technique, fibers may be used of a web through heated air passing through this web, depressed or is pressed, at least partially melted or partially be melted. Solidifies a melted fiber, the on an adjacent, optionally also fused fiber is present, it comes to bond formation. In general, it is enough already out when the bond formation to undergo nonwoven fabric the heated one Air about five is suspended for ten seconds. The air temperature should be here preferably chosen such be that at least the outer areas Partially soften the fibers. To a through-air-bonding technique It is accordingly to obtain bonded or consolidated nonwoven fabric advantageous that in the nonwoven at least partially such fibers present, which can be thermally softened and then again can freeze. Particularly suitable for this purpose are so-called bi- or tricomponent fibers. Alternatively or in addition thermoplastic fibers can also be used for these thermoplastic fibers Powders or granules used for bond formation or solidification become. These powders and granules are preferably uniform in the Nonwoven material whose fibers are not necessarily themselves in one embodiment for bonding formation by means of the through-air-bonding technique must be provided. The through air bonding step is preferably a carding step upstream, in which the fibers to be joined first in be aligned to a common orientation.

When Particularly advantageous absorbent articles such. B. Panty liners, sanitary napkins, diapers, incontinence pads or wound dressings, having at least one composite nonwoven fabric according to the invention.

The multilayer according to the invention Bonded nonwovens are demonstrably characterized by a special softness and yield and dispose about that beyond a pronounced absorbance as well as opposite conventional composite nonwoven systems also over an increased retention capacity, especially under pressure.

Further Features and advantages of the invention will become apparent from the following Description, in the embodiments will be explained in detail with reference to schematic drawings. there demonstrate:

1 a schematic cross-sectional view of a composite nonwoven structure according to the invention and

2 a schematic plan view of the top of a composite layer according to the invention.

The present invention is based on the surprising finding that a multilayer composite nonwoven could be found which characterized by special softness even in a very thin-layered state and the user nevertheless creates the sensation of fullness. In addition, even the upper, first nonwoven fabric layer contributes to good intake, retention and transfer properties for fluids. Despite the very flexible composite nonwoven structure obtained, its absorbency and retention capabilities are excellent and do not revert to the thicker absorbent sanitary products of the prior art. In particular, when pressure is applied, the liquid once absorbed is not released from the composite nonwoven structure according to the invention, or released only to a limited extent. The layer sequence found has proved to be particularly advantageous also because the fluid which has penetrated into the third layer is passed on very easily from this layer or is delivered to adjacent absorbent materials. Accordingly, the composite nonwoven structure according to the invention is particularly suitable for very thin, sheet-like, absorbent articles such as panty liners and sanitary napkins, but also exhibits its outstanding properties in diapers, incontinence pads or wound dressings.

1 shows an absorbent composite web according to the invention 1 comprising an upper first layer 2 , an intermediate second position 4 and a lower layer 6 , In the upper layer 2 it is a non-woven fabric layer of viscose fibers (50 wt .-%) and PE / PP bicomponent fibers (50 wt .-%) obtained by the airlaying technique with a weight per unit area of 30 g / m ² . Alternatively, the upper layer 2 in the present case, a non-woven fabric layer of viscose fibers (50% by weight) and PET / co-PET bicomponent fibers (50% by weight) with a surface fabric of 40 g / m ² . The intermediate layer 4 is formed in the present case by a particulate material of a superabsorbent polymer and z. B. be obtained by this particulate material during the manufacturing process to the lower layer 6 is scattered and has, for example, a basis weight of about 30 g / m ² . At this lower position 6 this is an SMS multilayer system composed of a first layer of spunbonded polypropylene, a second layer of meltblown polypropylene and a third layer of spunbond polypropylene, and e.g. B. may have a basis weight of 25 g / m ² .

With application of pressure and heat, depending on a suitably high temperature, a bond between the thermoplastic fibers of the lower layer 6 with the bicomponent fibers of the upper layer 2 be brought about. Suitable bicomponent fibers are regularly designed such that the lower melting polymeric material forms the sheath and the higher melting polymeric material forms the core.

Again 2 it can be seen, the upper and lower layer 2 respectively. 6 also with the help of adhesive lines 8th be connected to each other. These adhesive lines are preferably applied spaced apart in parallel direction in the machine direction (arrow). Between adjacent adhesive lines that will be in the intermediate layer 4 included superabsorbent material.

As an example, the absorption and retention capacity of a composite nonwoven structure according to the invention of a hydrophilic SMS top layer (basis weight 30 g / m ² ), an intermediate layer of superabsorbent particles (basis weight 20 g / m ² ) and a hydrophobic SMS-barrier layer (basis weight 30 g / m ² ) compared to a conventional airlaid-type structure containing 20% by weight of bicomponent fibers, 17% by weight of superabsorbent fibers and 63% by weight of pulp fibers having a basis weight of 80 g / m ² . It was found that the comparison structures prepared by means of airlaid technology had a lower absorption capacity than the composite nonwoven structure according to the invention and their retention capacity was about 50% worse than the structure according to the invention.

The absorbance the in outline form a sanitary napkin present laminate structure was tested by 7 ml of aqueous test liquid were dripped onto a point of the cover layer in such a way that each Drop penetrated into the laminate structure and was absorbed. Of the Period between the onset of the first fluid drop and the complete absorption the last drop of liquid was measured.

The retention capacity of this laminate structure was determined in such a way that the preceding described, with liquid soaked product covered with ten layers of filter paper MN 615 (Macherey and Nagel) and for was weighted for three minutes with a weight of 5 kg. The difference between the weight of the filter paper in the dry state and after three minutes Contact with the test liquid containing laminate structure served as a measure of their retention capacity.

The in the above description, in the drawings and in the claims disclosed features of the invention can both individually and also in any combination for the realization of the invention in their various embodiments be essential.

Claims (14)

Multilayer composite fleece comprising at least a first fibrous nonwoven layer comprising a mixture of fibers cellulose-based and thermoplastic fibers, at least a second layer comprising superabsorbent particles and / or superabsorbent fibers, and at least a third nonwoven layer, comprising at least partially hydrophobic spunbonded fibers. Composite nonwoven according to claim 1, characterized the thermoplastic fibers of the first layer are bicomponent fibers, Comprise multicomponent fibers, in particular. Composite nonwoven according to claim 1 or 2, characterized 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 includes any mixture thereof. Composite nonwoven according to one of the preceding claims, characterized characterized in that fibers based on cellulose natural cellulose fibers and / or regenerated cellulose fibers, in particular viscose, modal, Cupro and / or lyocell fibers. Composite nonwoven according to one of the preceding claims, characterized characterized in that the second layer is further thermoplastic Fibers, thermoplastic powders and / or thermoplastic granules and / or zeolites. Composite nonwoven according to one of the preceding claims, characterized characterized in that the third layer comprises at least one SM, SMS and / or SMMS laminate. Composite nonwoven according to one of the preceding claims, characterized by at least a fourth nonwoven fibrous layer comprising at least partially hydrophobic spunbonded fibers between the first and second layer is arranged. Composite nonwoven according to one of the preceding claims, characterized by at least a fifth Layer comprising superabsorbent particles and / or superabsorbent Fibers arranged between the first and the fourth layer is. Composite nonwoven according to one of the preceding claims, characterized characterized in that the first and fourth layers and / or the first and the third layer partially bonded together and / or welded, in particular heat-sealed, are. Composite nonwoven according to one of the preceding claims, characterized in that the first layer has a basis weight in the range of 15 to 100 g / m ² , in particular from 25 to 60 g / m ² , and / or the second and / or the fifth layer Basis weight in the range of 15 to 80 g / m ² , in particular in the range of 25 to 40 g / m ² , and / or have and / or the third and / or the fourth layer has a basis weight in the range of 5 to 60 g / m ² , in particular in the range of 15 to 30 g / m ² , or have. Composite nonwoven according to one of the preceding claims, characterized characterized in that the third and / or fourth layer further natural and / or manipulated natural Fibers include or include. Composite nonwoven according to one of the preceding claims, characterized characterized in that the first and / or fourth layer using the air-through-bonding technique and / or the calendering technique available is or are. Absorbent articles comprising at least one Composite nonwoven according to one of the preceding claims. Absorbent article according to claim 13, characterized characterized in that this article panty liners, sanitary napkins, diapers, Incontinence pads and wound dressings includes.