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Title:
A NONWOVEN WEB DESIGNED FOR USE AS A WIPES SUBSTRATE
Document Type and Number:
WIPO Patent Application WO/2018/184048
Kind Code:
A1
Abstract:
This invention relates to a nonwoven material suitable for use as a wipe Substrate, containing at least a first cellulosic nonwoven web, characterized in that the cellulosic nonwoven web is made from essentially pure cellulose formed of essentially continuous filaments and multibonded by merged filaments, hydrogen bonding and physical intermingling of the filaments, It further relates to the use of the inventive nonwoven material as a base sheet for the manufacture of a dry wipe, a wet wipe and a water-activated wipe.

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:
AT2017/000029
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; B32B5/02; B32B5/26; D04H1/4374; D04H1/485; D04H1/56; D04H3/013; D04H3/11
Domestic Patent References:
WO2007124521A12007-11-08
WO2009105490A12009-08-27
WO2004001128A12003-12-31
Foreign References:
US20100167029A12010-07-01
US20090324926A12009-12-31
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US7194788B22007-03-27
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US4442161A1984-04-10
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US6101661A2000-08-15
US6996871B12006-02-14
US7096531B22006-08-29
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US7422660B22008-09-09
US9220389B22015-12-29
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US8461066B22013-06-11
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US8012565B22011-09-06
US8191214B22012-06-05
US8263506B22012-09-11
US8318318B22012-11-27
EP1093536B12003-10-01
EP2013390B12015-08-19
EP2212456B12015-07-22
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Claims:
Claims

1. A nonwoven material suitable for use as a wipe substrate, containing at least a first cellulosic nonwoven web, characterized in that the cellulosic nonwoven web is made from essentially pure cellulose formed of essentially continuous filaments and multibonded by merged filaments, hydrogen bonding and physical intermingling of the filaments.

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

3. The nonwoven material of Claim 1 where the first cellulosic nonwoven web is made according to a lyocell process.

4. The nonwoven material of Claim 1 where a second 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.

5. A nonwoven material according to claim 1 , wherein the number of layers is at least two, preferably between two and ten, with a further preferred range from 2 to 6.

6. The nonwoven material of Claim 5, where the layers are formed of essentially continuous filaments, pulp fiber or staple fiber, and subsequently all layers are bonded together bonded together using merged filament bonding, hydrogen bonding and filament intermingling.

7. The nonwoven material of Claim 5, where the layers are formed of essentially continuous filaments, pulp fiber or staple fiber, and subsequently all layers are hydroentangled together.

8. The nonwoven material of Claim 1 , where one or more of the cellulosic nonwoven layers within the nonwoven material, if formed of essentially continuous filaments, are made according to a lyocell process.

9. The nonwoven material of Claim 1 , where the average filament diameters of the different cellulosic nonwoven layers within the nonwoven material, if formed of continuous filaments, are different.

10. The nonwoven material of any of Claims 1 to 9, where at least one cellulosic nonwoven web is essentially formed of pulp fiber according to an airlaid or wetlaid process.

11. Use of the nonwoven material of claim 1 as a base sheet for the manufacture of a dry wipe.

12. Use of the nonwoven material of claim 1 as a base sheet for the

manufacture of a wet wipe, such wipe being loaded with a functional solution designed for skin cleaning, antibacterial or disinfecting purposes and/or hard surface cleaning.

13. Use of the nonwoven material of claim 1 as a base sheet for the

manufacture of a water-activated wipe, such wipe being loaded with a low moisture content functional solution that is designed for skin cleaning, antibacterial or disinfecting purposes and/or hard surface cleaning, that can be packaged essentially dry and water-activated at the point of use.

14. A compostable dry wipe substrate containing a nonwoven material

according to claim 1 as a base sheet.

15. A compostable wet wipe substrate containing (a) a nonwoven material according to claim 1 as a base sheet and (b) a chemical solution.

16. A compostable water-activated wipe substrate containing (a) a

nonwoven material according to claim 1 as a base sheet and (b) a low moisture content chemical solution.

17. The compostable wipe substrate of Claim 14,15 & 16 wherein the nonwoven material is further bonded or treated by a hydroentanglement process.

Description:
A nonwoven web designed for use as a wipes substrate

This invention relates to a nonwoven web suitable to be used as wipes substrate, 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, providing strength, dimensional stability, abrasion resistance, absorbency, low linting and is biodegradable and compostable.

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 wipe substrate.

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.

Prior Art

The use of nonwovens in wipes is well known. U.S. 3,879,257 describes a cellulosic nonwoven describes as double re-crepe, or DRC, bonded with a latex binder. Coform is a nonwoven combining meltblown polyolefin with wood pulp and is described in U.S. 4,818,464, U.S. 4,100,324 and U.S.

8,846,116. U.S. 3,978,185, U.S. 8,333,918 and U.S. 7,994,079 describes a 100% meltblown polyolefin nonwoven used for wipers. U.S. 7,194,788 describes a hydroentangled composite material containing both staple length fibres as well as meltblown polyolefin webs. U.S. 3,494,821 , U.S. 4,144,370 and U.S. 7,331 ,089 describe continuous filament webs hydroentangled with staple length fibres, while U.S. 3,917,785 and U.S. 4,442,161 describe wood pulp hydroentangled with staple fibres. U.S. 3,965,519 describes a

nonwoven with reinforcement and bonding for use in wipes, U.S. 6,101 ,661 , U.S. 6,996,871 , and U.S. 7,096,531 describe a multilayer nonwoven wiper with density gradients to facilitate solution holding, dispensing and recovering; U.S. 6,762,138 and U.S. 7,422,660 describe a wetlaid nonwoven hydroentangled with an additional nonwoven layer, U.S. 9,220,389 describes a multilayer airlaid nonwoven with a meltblown nonwoven cover, and U.S. 8,250,719 describes an airlaid nonwoven hydroentangled with another nonwoven. U.S. 5,652,049 describes a composite, multilayer nonwoven comprised of a base nonwoven layer and an antibacterial nonwoven layer, which are then hydroentangled together. This patent teaches that the base nonwoven layer can be composed of cellulose spunbond, polypropylene spunbond, or polypropylene thermal bonded nonwovens. U.S. 6,986,897 teaches the use of a latex bonded carded cellulosic nonwoven as a base sheet for a wipe. U.S. 8,461 ,066 teaches the use of a bulked, crimped cellulosic tow nonwoven for wipes. U.S. 8,748,693 describes a nonwoven including two or more layers of meltspun polymers physically entangled to make a web suitable for wipes. U.S. 3,811 ,957 describes a hydrophobic meltblown polyolefin nonwoven with low linting, good cleaning, which is also treated to add hydrophilicity. U.S. 6,117,515 describes an absorbent nonwoven laminated between apertured films to provide both surface cleaning and absorbency, U.S. 7,968,480 describes a 100% multi-lobal polyolefin spunlaid nonwoven.

There has been a great deal of research into nonwovens for wipes substrate, as there are many and diverse needs for such a material. A wipe substrate must be strong, both dry and wet. It must be abrasion resistant and dimensionally stable, again both dry and wet. It must be able to clean a surface, and be absorbent to both hold lotions and remove spent cleaning fluids. It should not lint or shed fibres in use. B iod eg rad ability and

compostability are both strong desires for such products.

Existing products are either very strong, dimensionally stable, abrasion resistant and low linting, but lack absorbency, biodegradability and

compostability, notably spunbond, meltblown, and coform nonwovens, or are not as strong or dimensionally stable and can lint or shed fibres, but are more absorbent like spunlace and airlaid nonwovens. Those few existing products which are biodegradable and compostable are relatively weak, and not very dimensionally stable or abrasion resistant. These nonwovens are 100% viscose, lyocell or cotton spunlace, wood pulp/viscose or lyocell or cotton blends, or airlaid with special binders. Such products are additionally usually very expensive.

The present invention relates to the use of specially designed nonwoven substrates produced using novel variants of the spunlaid nonwoven process, comprising 00% 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 production methods for, or products addressing the specific requirements for wipes substrates.

Problem

There are some common problems inherent in all current nonwovens used as wipes media. To be commercially useful, wipes substrate must be capable of cleaning diverse surfaces, must be abrasion resistant, strong both wet and dry, dimensionally stable both wet and dry, should not lint or shed fibres, must be absorbent enough to hold and dispense liquids and/or remove spent liquids from a surface. Biodegradability and/or compostability are also desired.

The problem with current technology is that it does not meet all needs, but involves trading off one need for another. The strongest and most

dimensionally stable nonwovens are the spunbond, meltblown and spunbond or meltblown composites. U.S. 8,333,918 and U.S. 7,994,079 describe a 100% meltblown polyolefin nonwoven used for wipers. U.S. 7,194,788 describes a hydroentangled composite material containing both staple length fibres as well as meltblown polyolefin webs. These products have strength, dimensional stability and abrasion resistance, but lack surface cleaning ability, absorbency, biodegradability and compostability. Cellulose based nonwovens are more absorbent, biodegradable and compostable and better at surface cleaning, but are not as strong,

dimensionally stable or abrasion resistant. Cellulose based nonwovens, especially those containing wood pulp or short cut staple fibre, can and do lint or shed fibres. U.S. 3,879,257 describes a cellulosic nonwoven describes as double re-crepe, or DRC, bonded with a latex binder. Both wetlaid and airlaid nonwovens based on wood pulp are also well known as are carded nonwovens based on viscose, lyocell, or cotton. These do not have the strength, dimensional stability or abrasion resistance of the spunmelt based nonwovens, but are absorbent, biodegradable and compostable.

The best current products and technology involve combining cellulose based webs with polyolefin based nonwovens. Coform is a nonwoven combining meltblown polyolefin with wood pulp and is described in U.S. 4,818,464, U.S. 4,100,324 and U.S. 8,846,116. U.S. 7,194,788 describes a hydroentangled composite material containing both staple length fibres as well as meltblown polyolefin webs. U.S. 3,494,821 , U.S. 4,144,370 and U.S. 7,331 ,089 describe continuous filament webs hydroentangled with staple length fibres, while U.S. 3,917,785 and U.S. 4,442,161 describe wood pulp hydroentangled with staple fibres. U.S. 6,762,138 and U.S. 7,422,660 describe a wetlaid nonwoven hydroentangled with an additional nonwoven layer, U.S. 9,220,389 describes a multilayer airlaid nonwoven with a meltblown nonwoven cover, and U.S. 8,250,719 describes an airlaid nonwoven hydroentangled with another nonwoven. U.S. 6,986,897 teaches the use of a latex bonded carded cellulosic nonwoven as a base sheet for a wipe. U.S. 8,461 ,066 teaches the use of a bulked, crimped cellulosic tow nonwoven for wipes. U.S. 6,117,515 describes an absorbent nonwoven laminated between apertured films to provide both surface cleaning and absorbency,

The need for a general wipes substrate material is for it to have the cost, absorbency, surface cleaning, and biodegradability of a cellulosic based nonwoven with the lack of linting, strength, dimensional stability and abrasion resistance of a spunlaid polyolefin nonwoven. Description

It is an object of the present invention to provide a nonwoven material suitable for use as a wipes substrate, containing at least a first cellulosic nonwoven web, wherein the cellulosic nonwoven web is made from essentially pure cellulose formed of essentially continuous filaments and multibonded by merged filaments, hydrogen bonding and/or physical intermingling of the filaments.

Such a nonwoven material according to the invention will provide excellent strength, dimensional stability wet and dry, abrasion resistance, excellent absorbency, excellent surface cleaning capabilities, does not lint or shed fibers in use, and is biodegradable, compostable and based on renewable resources.

The nonwoven material according to the invention is used as a wipes substrate that is designed to be a cost effective, biodegradable and

sustainable nonwoven that is strong, absorbent, dimensionally stable (wet and dry), abrasion resistant, soft and non-irritating with excellent skin cleaning properties. This nonwoven material which is essentially pure cellulose formed from essentially continuous filaments will provide the low linting, dimensional stability, and strength of a meltspun polyolefin with the absorbency of a cellulosic nonwoven in a cost effective, biodegradable and sustainable product.

The process used to manufacture the inventive nonwoven web is a solution blown spinning process, which is often referred to as a cellulosic spunlaid process. The process is using a spunbond or meltblown die or head to form the continuous filaments, in principle known from the prior art cited above.

The degree of merged filament bonding also results in a wider range of filament diameters and cross-sections being present. This characteristic enables additional cleanability versus nonwoven webs with a tight range of fiber and/or filament diameters. Preferably the inventive nonwoven material is further bonded or treated by a hydroentanglement, needlepunch or chemical bonding process to modify the physical properties.

The first cellulosic nonwoven web is preferably 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. 8,318,318; 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 further preferred embodiment of the invention the nonwoven material contains a second layer, consisting of a cellulosic nonwoven web, which is formed of essentially continuous filaments, pulp fiber or staple fiber, which is formed on top of the first cellulosic nonwoven web, and subsequently both layers are hydroentangled together. One useful advantage of two layers is that one layer can be higher density, and have a more abrasive surface and clean a surface better ("scrubby layer") while the other is lower density, and more absorbent ("absorbent layer"). Another useful advantage of a dual-layer structure is that one layer can be designed to provide the tensile strength, while another layer can be designed to provide the absorbency, cleanability, or other desired attribute.

In a further preferred embodiment of the invention the nonwoven material contains a third layer, consisting of a cellulosic nonwoven, which is formed of essentially continuous filaments, pulp fiber or staple fiber, which is formed on top, and subsequently all three layers are hydroentangled together Here, another useful advantage is to have one outer layer as high density for cleaning a surface ("scrubby layers"), another outer layer to have a high surface area for excellent cleanability with the center layer designed to have a high absorbent capacity.

In especially preferred embodiments of the invention one or more of the cellulosic nonwoven layers within the nonwoven material, if formed of essentially continuous filaments, are made according to a lyocell process. As known to an expert in the art, the lyocell process allows for use of a sustainable raw material (pulp) and provides a final filament with high purity (very low residual chemicals).

In particularly preferred embodiments of a two-layer material according to the invention either both layers consist of continuous filaments, made according to a lyocell process, or one layer consist of continuous filaments, made according to a lyocell process, and the second layer consist of pulp fiber.

In particularly preferred embodiments of a three-layer material according to the invention either all three layers consist of continuous filaments, made according to a lyocell process, or the two outer layers consist of continuous filaments, made according to a lyocell process, and the middle layer consist of pulp fiber.

It is another object of the present invention to use the nonwoven material as described above as a base sheet for the manufacture of a compostable industrial cleaning wipe. The resulting wipe is both water and oil absorbent, has acceptable consumer acceptable drape and softness and is compostable and based on renewable resources.

Still another object of the present invention is to provide a compostable industrial cleaning wipe, containing the inventive nonwoven material according as a base sheet.

In a preferred embodiment of the invention, the nonwoven material of the compostable industrial cleaning wipe is further process by hydroentanglement. Undergoing this additional process enables a greater range of wipe functionality design. Such attributes as thickness, drape, softness, strength and aesthetic appearance can be tailored to meet specific wipe requirements.

It is another object of the present invention to use the nonwoven material as described above as a wipes substrate, such wipe being dry for its intended use. It is another object of the present invention to use the nonwoven material as described above as a wipes substrate, such wipe being loaded with a low moisture content chemical solution. Suitable solutions for specific applications of such wipes substrates are in principle well known to the expert. This low moisture chemical solution allows the wipe to essentially dry when packaged and water activated at the point of use. This gives remarkable economic and handling advantages to the retailers as well as to the end consumers.

It is another object of the present invention to use the nonwoven material as described above as a wipes substrate, such wipe being loaded with a chemical solution. These chemical solutions are functional solutions designed for skin cleaning, antibacterial or disinfecting purposes and/or hard surface cleaning. Such specific applications of such wipes substrates are in principle well known to the expert. These wipes will be packaged wet and ready for use.

Still another object of the present invention is to provide a compostable wipes substrate, such wipe containing the inventive material, and being dry for its intended use. A wipes substrate according to the invention has low linting, has good dimensional stability, is absorbent, provides excellent cleanability for surfaces and skin, is soft and strong, is non-irritating to skin, and is

biodegradable, compostable and based on renewable resources.

Still another object of the present invention is to provide a compostable wipes substrate, such wipe containing (a) a nonwoven material according to claim 1 as a base sheet and (b) a low moisture content chemical solution. A wipes substrate according to the invention can be loaded with a low moisture content chemical solution, has low linting, has good dimensional stability (wet and dry), is absorbent, provides excellent clean ability for hard surfaces and skin, is soft and strong, is non-irritating to skin, and is biodegradable, compostable and based on renewable resources. That wiper can be

packaged dry and water activated just prior to use. This gives remarkable economic and handling advantages to the retailers as well as to the end consumers. Still another object of the present invention is to provide a compostable wipes substrate, such wipe containing (a) a nonwoven material according to claim 1 as a base sheet and (b) a chemical solution. A wipes substrate according to the invention can be loaded with a chemical solution, has low linting, has good dimensional stability (wet and dry), is absorbent, provides excellent clean ability for hard surfaces and skin, is soft and strong, is non-irritating to skin, and is biodegradable, compostable and based on renewable resources. This wipe is packaged wet and ready for use.

In a preferred embodiment of the invention the nonwoven material of the compostable healthcare wiper is further bonded or treated by a

hydroentanglement process.

The invention will now be illustrated by examples. These examples are not limiting the scope of the invention in any way. The invention includes also 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 50-gsm fabric of the invention was analyzed for water uptake versus a 50 gsm commercial product being comprised of SBPP (spunbond polypropylene) + wetlaid pulp, hydroentangled.

The 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 when the amount of water taken up is below 0.005g/20sec Figure 1 shows water uptake speed, average of 5 measurements. Sample 1 is cellulosic; fabric of invention, sample 2 is a commercial sample (spunbond polypropylene, wetlaid pulp and hydroentangled)

In figure 1 it can be seen that the fabric of the invention has a much faster average liquid uptake and levels off at a higher average end value than the commercial sample. This is especially beneficial if water based body fluids are wiped.

Example 2

The product of invention of example 1 was tested for its visible wet lint by an in house built up method.

For this evaluation, the product of invention was wetted with water 3 fold (equilibrium time 2 h). Then it was used in MD for a wiping test wiping over a collagen foil, which was checked to be free of visible particles prior to test. The wiping equipment of this test system is simulating a real wiping

movement with 550 g wiping pressure. The product of invention showed within a threefold determination no visible wet lint within this test.

Example 3

A 40-gsm product of invention was compared in terms of stiffness to a commercial wipe product being SBPP (spunbond polypropylene) + wetlaid pulp, hydroentangled, also 40 gsm. The product of invention was showing 77 % less overall stiffness than the commercial wipe. This means that the product of invention is especially soft and drapeable and therefore fits perfectly for wiping uneven body surfaces.

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.