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Title:
A NONWOVEN MATERIAL DESIGNED FOR USE IN HYGIENE APPLICATIONS
Document Type and Number:
WIPO Patent Application WO/2018/184049
Kind Code:
A1
Abstract:
The invention relates to a nonwoven material suitable for use in hygiene applications, that comprises at least a first cellulosic nonwoven web, wherein the cellulosic nonwoven web contains essentially continuous essentially pure cellulose filaments which are multibonded by merged filaments, hydrogen bonding and physical intermingling of the filaments. It further relates to the use of a nonwoven material for the manufacture of a hygiene product as well as to a hygiene product that contains a nonwoven material as a base sheet or component.

Inventors:
CARLYLE, Tom (7261 Dellwood Creek Circle, Spanish Fort, Alabama, 36527, US)
EINZMANN, Mirko (Sandlingstrasse 9, 4600 Wels, AT)
GOLDHALM, Gisela (Mozartstrasse 2, 3363 Neufurth, AT)
HAYHURST, Malcolm, John (251 Nuneaton Road, Bulkington CV12 9RZ, GB)
MAYER, Katharina (Feldstrasse 39/12, 4813 Altmünster, AT)
SAGERER-FORIC, Ibrahim (Prinz-Eugen-Strasse 51, 4840 Vöcklabruck, AT)
Application Number:
AT2017/000030
Publication Date:
October 11, 2018
Filing Date:
April 03, 2017
Export Citation:
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Assignee:
LENZING AG (Werkstrasse 2, 4860 Lenzing, 4860, AT)
International Classes:
D04H1/4258; D01D5/098; D01F2/00; D04H1/492; D04H3/013; D04H3/11
Domestic Patent References:
WO1998026122A11998-06-18
WO2007124521A12007-11-08
Foreign References:
US20050056956A12005-03-17
US6235392B12001-05-22
US20100167029A12010-07-01
US4340563A1982-07-20
US3849241A1974-11-19
US4863785A1989-09-05
US5879343A1999-03-09
US8329979B22012-12-11
US5938995A1999-08-17
US5843063A1998-12-01
US8598406B22013-12-03
US7923597B22011-04-12
US5626571A1997-05-06
US5647862A1997-07-15
US6118218A2000-09-12
US5830604A1998-11-03
US7989062B22011-08-02
US8518311B22013-08-27
US6358461B12002-03-19
US7067444B22006-06-27
US8012565B22011-09-06
US8191214B22012-06-05
US8263506B22012-09-11
US8318318B22012-11-27
EP1093536B12003-10-01
EP2013390B12015-08-19
EP2212456B12015-07-22
Other References:
HAYHURST M J: "SPUNBOND CELLULOSE", CHEMICAL FIBERS INTERNATIONAL,, vol. 56, no. 6, 1 June 2006 (2006-06-01), pages 386, 388 - 390, 393, XP001503726, ISSN: 0340-3343
Download PDF:
Claims:
Claims

1. A nonwoven material suitable for use in hygiene applications, that comprises at least a first cellulosic nonwoven web, characterized in that the cellulosic nonwoven web contains essentially continuous essentially pure cellulose filaments which are multibonded by merged filaments, hydrogen bonding and physical intermingling of the filaments.

2. The nonwoven material of claim 1 where the cellulosic nonwoven web is made according to a lyocell process.

3. The nonwoven material of Claim 1 where the nonwoven web is further bonded or treated by a hydroentanglement, needlepunch or chemical bonding process to modify the physical properties.

4. The nonwoven material of Claim 1 , containing a second cellulosic nonwoven web, which consists of essentially continuous filaments, pulp fiber or staple fiber, is formed on top of the first cellulosic nonwoven web, and subsequently both layers are hydroentangled together.

5. The nonwoven material of Claim 4, containing a third cellulosic nonwoven, which consists of essentially continuous filaments, pulp fiber or staple fiber and is formed on top, and subsequently all three layers are hydroentangled together.

6. The nonwoven material of Claim 4 or 5, where one or more of the cellulosic nonwoven layers within the nonwoven material, if formed of continuous filaments, are made according to a lyocell process.

7. The nonwoven material of claim 1 where the basis weight is between 10 and 120 grams per square meter.

8. The nonwoven material of claim 1 which has modified absorbency, wicking, or other liquid handling properties due to a post treatment with chemicals, polymers or other materials of the individual nonwoven web or the nonwoven material as a whole.

9. Use of a nonwoven material according to claim 1 for the manufacture of a hygiene product.

10. Use of a nonwoven material according to Claim 9 where it is combined with another nonwoven material to produce a nonwoven composite for hygiene applications.

11. Use of a nonwoven material according to Claim 10 where it is combined with other nonwoven materials through hydroentanglement.

12. Use of a nonwoven material according to Claim 9 where the nonwoven web is post treated with chemicals, polymers or other materials to modify absorbency, wicking, or other liquid handling properties.

13. Use of a nonwoven material according to Claim 9, wherein the hygiene product is a baby diaper, feminine care pad, adult incontinence and/or tampon

14. A hygiene product characterized in that it contains a nonwoven material according to claim 1 as a base sheet or component.

15. A hygiene product according to Claim 14, which is a baby diaper, feminine care pad, adult incontinence and/or tampon.

Description:
A nonwoven material designed for use in hygiene applications

This invention relates to a nonwoven material suitable to be used as the base sheet for hygiene products, and more particularly, to an essentially pure cellulose nonwoven web formed from essentially continuous filaments and multibonded by merged filaments, hydrogen bonding and physical

intermingling of the filaments. This inventive nonwoven material provides liquid absorbency, fast wicking, fast liquid uptake, good spread ability of liquid, low linting, dimensional stability, softness, comfort, strength, biodegradability and sustainability.

The term "essentially pure cellulose" shall address the fact that cellulosic moulded bodies, e.g. made according to the lyocell process, always contain a small amount of polymers other than cellulose, namely hemicellulose. This does not influence in any way the suitability for the use according to this invention.

This invention further relates to additional bonding of this web alone, or to other webs or materials through hydroentangling to enhance these key performance properties needed in a cleaning and disinfecting wipe.

Prior Art

Hygiene applications here include baby diaper components, feminine hygiene components, and adult incontinence components. Some of these

components are topsheet, secondary topsheet (STS), backsheet, legcuffs, acquisition/distribution layer (ADL), absorbent core, and core wrap.

There are several types of nonwovens known for use in hygiene applications. Spunbonded and meltblown polypropylene as well as spunbond/meltblown /spunbond composites are widely used in topsheet and core wrap. U.S.

4,340,563 (for spunbond), U.S. 3,849,241 (for meltblown) and U.S. 4,863,785 (for spunbond/meltblown/spunbond composites) teach processes for producing products for use in hygiene applications. Airlaid and coform nonwovens are widely known and used in hygiene absorbent core, STS and ADL. U.S. 5,879,343, U.S. 8,329,979 and U.S. 5,938,995 all teach the use of airlaid in hygiene. U.S. 5,843,063, U.S. 8,598,406 and U.S. 7,923,597 all describe coform or coform type nonwovens (meltblown/airlaid composites or spunbond/airlaid composites) used in hygiene applications.

Airlaid and coform nonwovens are absorbent and hydrophilic, but strength and dimensional stability, especially wet, are issues as is linting. Additionally, they use some biodegradable raw materials but not 100%. Carded and

hydroentangled or spunlace nonwovens are also used in hygiene

applications. U.S. 5,626,571 teaches the use of both carded and

hydroentangled nonwovens for hygiene applications. Hydroentangled or spunlace nonwovens and carded nonwovens are often compromise products, containing both synthetic and cellulosic components. These have marginally acceptable absorbency, liquid wicking and dimensional stability, and are usually not biodegradable. The optimal product would combine the strength, low linting and dimensional stability of spunlaid nonwovens with the

absorbency, wicking, and biodegradabillty of cellulose based nonwovens.

There has been significant research in nonwovens for hygiene applications but the current technology is not yet optimal. Spunlaid polyolefins, as taught in U.S. 4,340,563, U.S. 3,849,241 , and U.S. 4,863,785 have excellent dimensional stability, low linting and high strength, but are not absorbent, hydrophilic or biodegradable. There have been many previous attempts to correct these issues. The lack of hydrophilicity is addressed by many prior art technologies. U.S. 5,647,862 discloses the technology of applying a coating of a surfactant to impart temporary hydrophilicity. However, it also admits that the hydrophilicity is temporary and depletes with each successive liquid insult. U.S. 6,118,218 discloses corona and plasma treatment to impart hydrophilicity to spunlaid polyolefins, but this treatment is transient, diminishing with time in storage. U.S. 5,830,604 discloses the technology for chemically grafting hydrophilic polymer chains onto the surface of polyolefins; this technology is complex and has many steps and is very costly. Finally, U.S. 7,923,597 discloses technology for polymerizing a sheath of hydrophilic polymers over the core of the polyolefin, suing a UV curable material. Again, this is very complex and costly. Biodegradabillty and sustainability are also addressed by prior art. U.S. 7,989,062 and U.S. 8,518,311 both disclose a spunlaid bicomponent fibre nonwoven where the bicomponent fibre is based on two biodegradable polyesters. Again, this is an expensive and complex technology.

The present invention relates to the use of specially designed nonwoven substrates produced using novel variants of the spunlaid nonwoven process, comprising essentially pure cellulose polymers. There are known methods and products using spunlaid cellulose webs. U.S. 6,358,461 , U.S. 7,067,444, U.S. 8,012,565, U.S. 8,191 ,214, U.S. 8,263,506 and U.S. 8,318,318 all teach methods for producing and using spunlaid cellulose webs. None of these teaches either production methods for or products addressing the specific substrate requirements for products used in hygiene applications.

Problem

Hygiene applications for nonwovens includes several specific products, including baby diaper components, feminine hygiene components, and adult incontinence components. Some of these components are topsheet, secondary topsheet (STS), backsheet, legcuffs, acquisition/distribution layer (ADL), absorbent core, and core wrap. Each of these components has specific need, but most hygiene applications share some common

requirements. Most require absorbency and liquid wicking (topsheet, STS, ADL, core and core wrap). Most require dimensional stability, even wet. Most require fast liquid take up or acquisition. Most require good spreadability of liquids (to use as much of the product as possible rather than only product near the liquid introduction point). All require strength and low linting.

Biodegradability and sustainability are strongly desired for all hygiene applications.

The problem with current hygiene nonwovens technology is that none addresses all of the needs. Meltspun polyolefins and products incorporating them are not very absorbent or biodegradable or sustainably sourced.

Cellulosic nonwovens or products incorporating cellulosic fibres are typically not low linting, or dimensionally stable especially when wet, and may not be strong enough or soft enough for some hygiene tasks. An optimal solution is not available.

There is distinct need for a strong, soft, absorbent, liquid wicking, fast liquid uptaking, good liquid spreading, non-irritating (comfortable), dimensionally stable (even wet), low tinting, cost effective and biodegradable material for use in nonwovens for hygiene applications.

Description

It is the object of the present invention to provide a nonwoven material suitable for use in hygiene applications, that comprises at least a first cellulosic nonwoven web, wherein the cellulosic nonwoven web contains essentially continuous essentially pure cellulose filaments which are multibonded by merged filaments, hydrogen bonding and physical intermingling of the filaments. The nonwoven material according to the invention has good absorbency, has fast liquid uptake, has good spreadability of liquid, has good liquid wicking, has low linting, has good dimensional stability (wet and dry), is soft and strong, is non-irritating, and is biodegradable and made from sustainable raw materials.

For concise description purposes, we will use the term hygiene products to reference all baby diaper products, a women's feminine care pad product, a tampon product and/or any adult incontinence product, with the requirement that these products must contain at least one component that includes at least one nonwoven material.

Preferably, the cellulosic nonwoven web is made according to a lyocell process.

Cellulosic fibres can be produced by various processes. In one embodiment a lyocell fibre is spun from cellulose dissolved in N-methyl morpholine N-oxide (NMMO) by a meltblown process, in principle known from e.g. EP 1093536 B1 , EP 2013390 B1 and EP 2212456 B1. Where the term meltblown is used it will be understood that it refers to a process that is similar or analogous to the process used for the production of synthetic thermoplastic fibres (filaments are extruded under pressure through nozzles and stretched to required degree by high velocity/high temperature extension air flowing substantially parallel to the filament direction), even though the cellulose is dissolved in solution (i.e. not a molten thermoplastic) and the spinning & air temperatures are only moderately elevated. Therefore the term "solution blown" may be even more appropriate here instead of the term "meltblown" which has already become somewhat common for these kinds of technologies. For the purposes of the present invention both terms can be used synonymously. In another embodiment the web is formed by a spun bonding process, where filaments are stretched via lower temperature air. In general, spunbonded synthetic fibres are longer than meltblown synthetic fibres which usually come in discrete shorter lengths. Fibres formed by the solution blown lyocell process can be continuous or discontinuous depending on process conditions such as extension air velocity, air pressure, air temperature, viscosity of the solution, cellulose molecular weight and distribution and combinations thereof.

In one embodiment for making a nonwoven web the fibres are contacted with a non-solvent such as water (or water/NMMO mixture) by spraying, after extrusion but before web formation. The fibres are subsequently taken up on a moving foraminous support to form a nonwoven web, washed and dried.

Freshly-extruded lyocell solution ('solvent spun', which will contain only, for example, 5-15% cellulose) behaves in a similar way to 'sticky' and deformable thermoplastic filaments. Causing the freshly-spun filaments to contact each other while still swollen with solvent and with a 'sticky' surface under even low pressure will cause merged filament bonding, where molecules from one filament mix irreversibly with molecules from a different filament. Once the solvent is removed and coagulation of filaments completed, this type of bonding is impossible.

It is another object of the present invention to provide a process for the manufacture of a nonwoven material consisting of essentially continuous cellulosic filaments by:

a. Preparation of a cellulose-containing spinning solution b. Extrusion of the spinning solution through at least one spinneret containing closely-spaced meltblown jet nozzles

c. Attenuation of the extruded spinning solution using high velocity air streams,

d. Forming of the web onto a moving surface [e.g. a perforated belt or drum], e. Washing of the formed web

f. Drying of the washed web

wherein in step c. and/or d. coagulation liquor, i.e. a liquid which is able to cause coagulation of the dissolved cellulose; in a lyocell process this preferably is water or a diluted solution of NMMO in water, is applied to control the merged filament bonding. The amount of merged filament bonding is directly dependent on the stage of coagulation of the filaments when the filaments come into contact. The earlier in the coagulation process that the filaments come into contact, the greater the degree of filament merging that is possible. Both placement of the coagulation liquor application and the speed at which the application liquor is applied can either increase, or decrease, the rate of coagulation. Which results in control of the degree (or amount) of merged filament bonding that occurs in the material.

Preferably the merged filament bonding is further controlled by filament spinning nozzle design and arrangement and the configuration and temperature of filament extension air. The degree of molecular alignment that is present as the solution exits the spinning nozzle has an impact on the coagulation rate. The more aligned the molecules are, the faster the coagulation rate, and conversely, the less aligned the molecules are, the slower the coagulation rate. The spinning nozzle design and arrangement, along with the molecular weight of the cellulosic raw material used will determine the starting coagulation rate at the exit of the spinning nozzle. Additionally, the rate of cooling (temperature decrease) of the solution upon spinning nozzle exit will impact the coagulation rate as well. The slower the cooling rate, the slower the coagulation rate, and conversely, the faster the cooling rate, the faster the coagulation rate. Therefore, configuration of the filament extension air can directing impact the cooling rate and therefore, impact the coagulation rate, which impacts the achievable amount of merged filament bonding that is possible.

In a preferred embodiment of the process according to the invention at least two spinnerets (also known as jets), preferably between two and ten, and further preferred between 2 and 6, each one arranged to form a layer of nonwoven web, are used to obtain a multilayer nonwoven material. By applying different process conditions at the individual spinnerets it is even possible to obtain a multilayer nonwoven material wherein the individual layers have different properties. This may be useful to optimize the nonwoven material according to the invention for different applications. In one

embodiment this could provide a gradient of filament diameters from one side of the material to the other side by having each individual web having a standard filament diameter that is less than the web on top, it is possible to create a material suitable for use as an air filter media that will provide a gradient of pore size (particle size capture). This will provide an efficient filtration process and result in a lower pressure drop across the filter media compared to a single web with similar characteristics at the same basis weight and pore size distribution.

Preferably the filaments are spun using a solution of cellulose in an aqueous amine oxide and the coagulation liquor is water, preferably with a content of amine oxide not being able to dissolve cellulose, also referred to as a lyocell process; the manufacture of such a solution is in principle known, e.g. from U.S. 6,358,461 , U.S. 7,067,444, U.S. 8,012,565, U.S. 8,191 ,214, U.S.

8,263,506 and U.S. 8,318,3 8; preferably the amine oxide is NMMO.

The present invention describes a cellulosic nonwoven web produced via a meltblown or spunbond-type process. The filaments produced are subjected to touching and/or compaction and/or intermingling at various points in the process, particularly before and during initial web formation. Contact between filaments where a high proportion of solvent is still present and the filaments are still swollen with said solvent causes merged filament bonding to occur. The amount of solvent present as well as temperature and contact pressure (for example resulting from extension air) controls the amount of this bonding. In particular the amount of filament intermingling and hydrogen bonding can be limited by the degree of merged filament bonding. This is the result of a decrease in filament surface area and a decrease in the degree of flexibility of the filaments. For instance, as the degree of merged filament bonding increase, the amount of overall surface area is decreased, and the ability of cellulose to form hydrogen bonds is directly dependent on the amount of hydroxyl groups present on the cellulosic surface. Additionally, filament intermingling happens as the filaments contact the forming belt. The filaments are traveling at a faster rate of speed than the forming belt. Therefore, as the filament contacts the belt, it will buckle and sway side to side, and back and forth, just above the forming belt. During this buckling and swaying, the filaments will intermingle with neighboring filaments. If the filaments touch and merge prior to the forming belt, this limits the number of neighboring filaments by which it can intermingle with. Additionally, filaments that merge prior to contacting the forming belt with not have the same degree of flexibility as a single filament and this will limit the total area over which the filament will buckle and sway.

Surprisingly, it has been found that high levels of control of filament merging can be achieved by modifying key process variables. In addition, physical intermingling of at least partially coagulated cellulose filaments can occur after initial contact with non-solvent, particularly at initial filament laydown to form the web. It arises from the potential of the essentially continuous filaments to move laterally during initial filament formation and initial laydown. Degree of physical intermingling is influenced by process conditions such as residual extension air velocity at the foraminous support (forming belt). It is completely different from the intermingling used in production of webs derived from cellulose staple fibers. For staple fibers, an additional process step such as calendaring is applied after the web has been formed. Filaments which still contain some residual solvent are weak, tender and prone to damage.

Therefore, in combination with controlling degree and type of bonding at this stage, it is essential that process conditions are not of a type which could cause filament and web damage. Initial drying of the washed but never-dried nonwoven, together with optionally compacting, will cause additional hydrogen bonding between filaments to develop. Modifying temperature, compacting pressure or moisture levels can control the degree of this hydrogen bonding. Such treatment has no effect on intermingling or the merged filament bonding.

In a preferred embodiment of the invention the nonwoven material is dried prior to subsequent bonding/treatment.

In a preferred embodiment of the invention the percentage of each type of bonding is controlled using a process with up to two compaction steps, where one of these compaction steps is done after step d. of the inventive process where the spun filaments are still swollen with a solvent, and one of these compaction steps is done before or in step e. of the inventive process where all or most of the solvent has been removed and the web has been wet with water. As previously discussed, control of the coagulation of the spun solution is a factor in controlling the degree of merged filament bonding. This preferred embodiment concerns decreasing the coagulation rate to a state where additional compaction steps can be used after filament laydown to further increase the actual amount of merged filament boding that is achievable. It might be helpful to view the maximum achievable filament bonding as the state where we have merged all filaments into an essentially film-like structure.

The present invention describes a process and product where merged filament bonding, physical intermingling and hydrogen bonding can be controlled independently. However, the degree of merged filament bonding can limit the degree of physical intermingling and hydrogen bonding that can occur. In addition, for the production of multi-layer web products, process conditions can be adjusted to optimise these bonding mechanisms between layers. This can include modifying ease of delamination of layers, if required.

In addition to merged filament, intermingling and hydrogen bonding being independently set as described above, additional bonding/treatment steps may optionally be added. These bonding/treatment steps may occur while the web is still wet with water, or dried (either fully or partially). These

bonding/treatment steps may add additional bonding and/or other web property modification. These other bonding/treatment steps include hydroentangling or spunlacing, needling or needlepunching, adhesive or chemically bonding. As will be familiar to those skilled in the art, various post- treatments to the web may also be applied to achieve specific product performance. By contrast, when post-treatments are not required, it is possible to apply finishes and other chemical treatments directly to the web of this invention during production which will not then be removed, as occurs with, for example, a post-treatment hydroentanglement step.

Varying the degree of merged filament bonding provides unique property characteristics for nonwoven cellulose webs with regards to softness, stiffness, dimensional stability and various other properties. Properties may also be modified by altering the degree of physical intermingling before and during initial web formation. It is also possible to influence hydrogen bonding, but the desired effect of this on web properties is minor. Additionally, properties can be adjusted further by including an additional

bonding/treatment step such as hydroentangling, needlepunching, adhesive bonding and/or chemical bonding. Each type of bonding/treatment provides benefits to the nonwoven web. For example, hydroentangling can add some strength and soften the web as well as potentially modifying bulk density; needling is typically employed for higher basis weights and used to provide additional strength; adhesive and chemical bonding can add both strength and surface treatments, like abrasive material, tackifiers, or even surface lubricants.

The present invention allows independent control of the key web bonding features: merged filaments, intermingling at web formation, hydrogen bonding and optional additional downstream processing. Manipulation of merged filament bonding can be varied to predominantly dictate the properties of the nonwoven web.

In a preferred embodiment of the invention, the nonwoven web is

hydroentangled. Undergoing this additional process enables a greater range of material functionality design. Such attributes as thickness, drape, softness, strength and aesthetic appearance can be tailored to meet specific consumer requirements.

Preferably the nonwoven web of the nonwoven material according to the invention is further bonded or treated by a hydroentanglement, needlepunch or chemical bonding process to modify the physical properties.

This material is designed to be a sustainable and cost effective nonwoven with good absorbency. It is clear that an essentially pure cellulosic material has better absorbent capacity and superior liquid management properties (liquid uptake, good spreadability and good wicking) than synthetic polymers such as polypropylene and polyester, which are typically used for the majority of hygiene components.

The challenge is to also include the properties of low linting, good dimensional stability (wet and dry), soft and strong, and being non-irritating, because these properties are the key advantages to using synthetic polymers which are included in the majority of hygiene products today. The inventive material, which is essentially pure cellulosic, is able to achieve low linting, good dimensional stability (in both the wet and dry state) and can be both soft and strong. The advantages of the multibonding used in the inventive material is that high strength, low elongation and good stiffness are all achieved. This combination enables the material to exhibit very good dimensional stability and a high strength as an essentially pure cellulosic material. It also provides the low linting character that comes from good filament tie-down (merged filaments) and does not negatively influence the excellent softness that cellulosic materials are known to exhibit, and this translates into a

comfortable, non-irritating material that can be used next to the user's skin. All of this is accomplished while being 100% biodegradable, compostable and made from 100% sustainable raw materials.

In a preferred embodiment, the basis weight is between 10 and 120 grams per square meter (gsm). Within this range, we find that targeted hygiene product performances can be achieved. Furthermore, for use as a topsheet, the preferred basis weight is between 10 and 25 gsm. For use as an acquisition and distribution layer, the preferred basis weight is between 35 and 120 gsm. For a secondary topsheet, the preferred basis weight is between 20 gsm and 60 gsm. For a core wrap, the preferred basis weight is between 15 and 40 gsm. For a backsheet, the preferred basis weight is between 20 and 75 gsm.

In another embodiment, the inventive material may be combined with another nonwoven material to produce a nonwoven composite for hygiene applications. These hygiene products are composite nonwoven products in themselves, and they may use individual components that are composites as well. One embodiment is that the inventive material could be combined with a film (or other material with liquid barrier properties) to serve as the backsheet for a baby diaper. In this embodiment, the inventive material would provide the soft hand required for a back sheet, where the film would provide the liquid barrier to prevent leakage through the diaper structure.

In a further preferred embodiment of the invention the nonwoven material contains a second layer, consisting of a cellulosic nonwoven web, which is essentially formed of continuous filaments, pulp fiber or staple fiber, is formed on top of the first cellulosic nonwoven web, and subsequently both layers are hydroentangled together.

In a further preferred embodiment of the invention the nonwoven material contains a third layer, consisting of a cellulosic nonwoven, which is essentially formed of continuous filaments, pulp fiber or staple fiber, is formed on top, and subsequently all three layers are hydroentangled together.

In especially preferred embodiments of the invention one or more of the cellulosic nonwoven layers within the nonwoven material, if formed of continuous filaments, are made according to a lyocell process.

In another embodiment, for applications where it would be desirable to maximize (or minimize) liquid wicking, the nonwoven web within the inventive nonwoven material is post treated with chemicals, polymers or other materials to modify absorbency, wicking, or other liquid handling properties. Such post treatments are known to one experienced in the art. The individual nonwoven webs or the nonwoven material as a whole can be post treated accordingly.

Still another object of the present invention is the use of a nonwoven material according to the invention for the manufacture of a hygiene product. In particular, the nonwoven material will be used therein as a base sheet or component.

In particular the nonwoven material according to the invention is combined with another nonwoven material to produce a nonwoven composite for hygiene applications. Nevertheless the nonwoven material can also be is used as an individual component.

Preferably the nonwoven material according to the invention is combined with other nonwoven materials through hydroentanglement. In order to modify absorbency, wicking, or other liquid handling properties of the nonwoven material for use in hygiene products according to the invention it can be post treated with chemicals, polymers or other materials.

Typically, the nonwoven material according to the invention can be used in a hygiene product such as baby diaper, feminine care pad, adult incontinence and/or tampon. Nevertheless, many other applications, where the properties of the inventive nonwoven material are beneficial, are possible.

Still another object of the present invention is to provide a hygiene product characterized in that it contains a nonwoven material according to the invention as a base sheet or component. Typically, such a hygiene product can be a baby diaper, feminine care pad, adult incontinence and/or tampon. Nevertheless all other hygiene product, where the properties of the inventive nonwoven material are beneficial, are within the scope of the invention.

The invention will now be illustrated by examples. These examples are not limiting the scope of the invention in any way. The invention also includes any other embodiments which are based on the same inventive concept. Examples

All samples for testing were conditioned at 23°C ±2°C rel. humidity 50% ±5% for 24 hours.

Example 1

A 35-gsm product of the invention was tested for water uptake speed versus a hydrophilic commercial product of the same basis weight being comprised of soft, carded thermal-bonded coarse denier fibers, polypropylene.

Water uptake was measured using an ATS (Absorbency Testing System, ATS-600). With that the test sample (sample size round, diameter 5 cm) is supplied with water from the bottom and water taken up by the sample without having any hydrostatic pressure is evaluated. The measurement for each sample is stopped after 1800 seconds.

Figure 1 shows water uptake speed, average of 5 measurements. Sample 1 (product of invention) versus sample 2 (commercial product, soft carded thermal-bonded coarse denier fibers, polypropylene, permanently hydrophilic).

In figure 1 , it can be seen that only the product of invention was taking up water even though the competitive product was hydrophilic polypropylene.

Example 2

The same two samples of example 1 were further tested for spreadability of liquid.

The test method was as follows: 0.5 ml of test liquid (water with 2g/L dye Sulfacide brilliant green) was pipetted onto each sample using an Eppendorf pipette. After 5 min, a picture of the liquid spread was taken and software (lmageJ1.49v, National Institute of Health, USA) used to evaluate the area of the liquid spread.

The product of invention showed a 2.7 fold higher area in spread liquid compared to the commercial product. Example 3

The same two samples of example 1 were further tested for their tensile properties in MD and CD and for their stiffness.

Tensile properties were measured according to standard method DIN EN 29 073 part 3/ISO 9073-3, although a clamping length of 8cm rather than 20cm was used. Stiffness was measured using a 'Handle-o-meter', according to standard method WSP 90.3, with ¼ inch slot width, stainless steel surface, 1000 g beam. Sample size was to 10 x 10 cm.

The product of invention achieved 18 % more tensile strength in MD and 42 % more tensile strength in CD compared to the commercial product and showed 4 times more overall stiffness. This shows that the product of invention is superior in tensile strength and dimensional stability.