EP4702185A1

EP4702185A1 - Hydroentangled nonwoven comprising cellulosic filaments

Info

Publication number: EP4702185A1
Application number: EP23723838.1A
Authority: EP
Inventors: Anna Nihlstrand; Mikael Strandqvist; Binh PHAN
Original assignee: Essity Hygiene and Health AB
Current assignee: Essity Hygiene and Health AB
Priority date: 2023-04-26
Filing date: 2023-04-26
Publication date: 2026-03-04
Also published as: CO2025014533A2; MX2025012513A; AU2023444996A1; WO2024223041A1; CN120936764A

Abstract

A hydroentangled nonwoven comprising manmade cellulosic filaments, natural cellulosic fibres, and manmade staple fibres. The manmade staple fibres have a length of 10 to 20 mm. A wipe comprising a hydroentangled nonwoven. A method of producing a nonwoven, wherein a web of manmade cellulosic filaments is provided and natural cellulosic fibres and manmade staple fibres are wet-formed on top of said web of manmade cellulosic filaments, thus forming a fibrous web comprising said manmade cellulosic filaments, natural cellulosic fibres and manmade staple fibres. The fibrous web is subsequently hydroentangled to form a nonwoven. A method of producing a wipe.

Description

HYDROENTANGLED NONWOVEN COMPRISING CELLULOSIC FILAMENTS

Technical field

The present invention relates to a hydroentangled nonwoven comprising manmade cellulosic filaments, to a wipe comprising such a hydroentangled nonwoven, to a method of producing a nonwoven, and to a method for producing a wipe.

Absorbing nonwoven materials are often used for wiping spills and leakages of all kinds in industrial, service, office and home locations. There are many demands put on nonwoven materials made for wiping purposes. An ideal wipe should be strong, absorbent, abrasion resistant and exhibit low linting. To meet such demands, an absorbing nonwoven material typically comprises fibres of different types, such as a combination of fibre filaments and staple fibres, as well as fibres of different origins, such as fossil-based plastic fibres and/or natural fibres. Following a desire for nonfossil or plastic free materials, manmade cellulosic fibres, often referred to as regenerated cellulose fibres, have been considered as a component of absorbing nonwoven materials.

WO 2018/184042 discloses a nonwoven material for use in an industrial cleaning wipe. The nonwoven material contains a cellulosic nonwoven web made from essentially pure cellulose formed of continuous filaments. The nonwoven material may comprise layers formed of essentially continuous filaments, pulp fiber or staple fiber, all layers subsequently being hydroentangled together. Also disclosed is a process for the manufacture of a nonwoven material consisting of essentially continuous cellulosic filaments.

WO 2005/042819 discloses a hydroentangled nonwoven material comprising continuous filaments, natural fibres and synthetic staple fibres. Also disclosed is a method of producing a nonwoven material. The method comprises forming of a fibrous web of continuous filaments on a forming fabric and applying a wet-formed fibre dispersion containing synthetic staple fibres and natural fibres on top of said continuous filaments, and subsequent hydroentangling of the fibrous web.

Summary of the invention

It is an object of the present invention to provide strength, particularly wet strength, to a nonwoven material comprising manmade cellulosic fibres. This object, as well as other objects being apparent to a skilled person studying the present description, are achieved by the hydroentangled nonwoven, the wipe and the methods of the appended claims.

It has thus been found that staple fibres having a length of 10 to 20 mm, preferably 10 to 15 mm, are advantageous in providing strength to a hydroentangled nonwoven comprising manmade cellulosic filaments and wood pulp fibres. A high ratio of wet tensile index to dry tensile index could thus be obtained, despite cellulose-based nonwovens normally having a much lower such ratio than nonwovens based on synthetic or fossil materials.

In a first aspect, the present invention relates to a hydroentangled nonwoven comprising manmade cellulosic filaments, natural cellulosic fibres, and manmade staple fibres, wherein the manmade staple fibres have a length of 10 to 20 mm, preferably 10 to 15 mm.

Staple fibres are natural fibres or cut lengths from manmade filaments. Staple fibres used in nonwovens typically have a length of 5 to 60 mm, such as 20 to 60 mm or 40 to 60 mm. Staple fibres include short fibres (also called shortcut fibres), having a length of less than 20 mm or less than 15 mm. Filaments are typically fibres that in proportion to their diameter are very long, in principle endless. Filaments include fibres being the result of filaments breaking during manufacturing or web formation.

The hydroentangled nonwoven may comprise 10 to 50 weight percent of the manmade cellulosic filaments, 20 to 85 weight percent of the natural cellulosic fibres; and 2.5 to 25 weight percent of the manmade staple fibres, the weight percentages being based on the total weight of the nonwoven. Alternatively, the hydroentangled nonwoven may comprise 15 to 35 weight percent of the manmade cellulosic filaments, 40 to 75 weight percent of the natural cellulosic fibres; and 5 to 20 weight percent of the manmade staple fibres, the weight percentages being based on the total weight of the nonwoven.

The manmade cellulosic filaments may be formed of cellulose of natural origin, such as regenerated cellulose. Regenerated cellulose is obtained by conversion of natural cellulose to a soluble cellulosic derivative and subsequent regeneration of the cellulose, typically forming fibres or filaments. Examples of regenerated cellulose are rayon, viscose, lyocell and acetate. Use of cellulosic filaments formed of cellulose of natural origin contributes to the provision of a bio-based or non-fossil nonwoven. It is preferred that the natural cellulose has not been chemically modified. Examples of natural cellulose that has not been chemically modified are viscose or lyocell, preferably lyocell. Use of cellulosic filaments formed of natural cellulose that has not been chemically modified further contributes to the provision of a plastic free nonwoven. Generally, the manmade cellulosic filaments may comprise a plurality of filament types.

The manmade cellulosic filaments are preferably solution-blown filaments. WO 2018/184042 discloses a process for the manufacture of a nonwoven material consisting of essentially continuous cellulosic filaments. The process involves preparation of a cellulose-containing spinning solution, such as cellulose dissolved in N-methyl morpholine N-oxide (NMMO), extrusion of the spinning solution through a spinneret, attenuation of the extruded spinning solution using high velocity air streams, forming of a web onto a moving surface, and washing and drying of the web. During attenuation and/or web forming, a coagulation liquor able to cause coagulation of the dissolved cellulose is applied. The process is described as similar or analogous to the “meltblown” process used to produce synthetic thermoplastic fibres. As the cellulose is dissolved in solution (i.e. , not a molten thermoplastic) and the spinning and air temperatures are only moderately elevated, the disclosed process is referred to as “solution blown”.

The natural cellulosic fibres may be pulp fibres, such as wood fibres. Wood fibres are especially well suited to use. Both softwood fibres and hardwood fibres are suitable. Also recycled wood fibres can be used. The fibre lengths will vary from around 3 mm for softwood fibres to around 1.2 mm for hardwood, and may be even shorter for recycled fibres. Many other types of natural fibres may as well be used, especially those that have a capacity to absorb water and a tendency to help in creating a coherent sheet. Examples of further natural cellulosic fibres are seed hair fibres, e.g., cotton, kapok, or milkweed; leaf fibres, e.g., sisal, abaca, pineapple, or New Zealand hemp; and bast fibres, e.g., flax, hemp, jute, or kenaf. The natural cellulosic fibres may originate from a plurality of natural sources.

The manmade staple fibres may be formed of polyethylene, polypropylene, polyester, polyamide, polylactide, polyhydroxyalkanoate or cellulose, preferably of polylactide, polyhydroxyalkanoate or cellulose, more preferably of cellulose. Use of staple fibres formed of polylactide, polyhydroxyalkanoate or cellulose contributes to the provision of a bio-based or non-fossil, as well as biodegradable and compostable, nonwoven. The manmade staple fibres may be formed of bio-based polyethylene, biobased polypropylene, bio-based polyester or bio-based polyamide. Use of staple fibres formed of bio-based polyethylene, bio-based polypropylene, bio-based polyester or biobased polyamide contributes to the provision of a bio-based or non-fossil nonwoven. Further, the manmade staple fibres may be formed of cellulose of natural origin, such as regenerated cellulose. Examples of regenerated cellulose are rayon, viscose, lyocell and acetate. Use of staple fibres formed of cellulose of natural origin contributes to the provision of a bio-based or non-fossil nonwoven. It is preferred that the natural cellulose has not been chemically modified. Examples of natural cellulose that has not been chemically modified are viscose or lyocell, preferably lyocell. Use of staple fibres formed of natural cellulose that has not been chemically modified further contributes to the provision of a plastic free nonwoven. Generally, the manmade staple fibres may comprise a plurality of fibre types.

A plastic-free nonwoven may be provided if the manmade cellulosic filaments and the manmade staple fibres are formed of natural cellulose that has not been chemically modified, more preferably of viscose or lyocell, most preferably of lyocell. The cellulosic filaments and the staple fibres may, respectively, be formed of the same natural cellulose that has not been chemically modified or of different natural celluloses that have not been chemically modified.

The hydroentangled nonwoven may have a basis weight of 20 to 200 g/m², preferably 40 to 120 g/m².

In a second aspect, the present invention relates to a wipe comprising a hydroentangled nonwoven as disclosed herein. A wipe is a disposable cloth for wiping objects clean. A wipe may be provided as a discrete sheet or as a roll of wipe material from which sheets of suitable length may be torn off.

The wipe may be a wet wipe, such as a wipe further comprising a liquid formulation. The liquid formulation may comprise a cleansing agent, a disinfectant and/or a soothing agent.

In a third aspect, the present invention relates to a method of producing a nonwoven, wherein a web of manmade cellulosic filaments is provided and natural cellulosic fibres and manmade staple fibres are wet-formed on top of said web of manmade cellulosic filaments, thus forming a fibrous web comprising said manmade cellulosic filaments, natural cellulosic fibres and manmade staple fibres, and the fibrous web is subsequently hydroentangled to form a nonwoven, wherein the manmade staple fibres have a length of 10 to 20 mm, preferably 10 to 15 mm.

Hydroentangling, or spunlacing, is described in CA 841 938. Hydroentangling involves forming a fibrous web, after which the filaments and fibres are entangled by means of very fine waterjets under high pressure. Several rows of water jets are directed against the fibrous web, which is supported by a movable fabric.

Typically, a fibre dispersion comprising the natural cellulosic fibres and the manmade staple fibres may be wet-formed on top of said web of manmade cellulosic filaments. The wet-formation of the natural fibres and the staple fibres on top of the web may thus be performed in one single operation. The manmade staple fibres may be foam-formed on top of said web of manmade cellulosic filaments. Foam-forming of the fibres contributes towards homogeneous formation. Staple fibres having a length of 10 to 20 mm are otherwise difficult to distribute evenly, particularly when in dispersion together with natural fibres.

In WO 96/02701 there is disclosed hydroentangling of a foam-formed fibrous web. Foam-forming is a special variant of wet-laying where the water besides fibres and chemicals also contains a surfactant which makes it possible to create a foam where the fibres can be enmeshed in and between the foam bubbles. The fibres can be pulp fibres and other natural fibres and synthetic fibres.

The web of manmade cellulosic filaments may be provided by extrusion of a cellulose-containing solution through a spinneret onto a moving surface, such as by solution-blowing of a cellulose-containing solution. Alternatively, the web of manmade cellulosic filaments may be provided as a pre-manufactured web, such as a roll of web material. It is preferred that the web of manmade cellulosic filaments has a basis weight of 2 to 50 g/m², preferably 15 to 40 g/m².

Additives, such as wet strength agents, binder chemicals, latexes, debonders, etc, may be added during production of the nonwoven.

The method of producing a nonwoven may be further characterized as set out for the hydroentangled nonwoven disclosed herein.

In a fourth aspect, the present invention relates to a method of producing a wipe, comprising a method of producing a nonwoven as set out herein, wherein the nonwoven further is cut, perforated, folded, micro-creped, calendered, embossed, printed and/or provided with a liquid formulation.

The method of producing a wipe may be further characterized as set out for the wipe disclosed herein.

Brief description of the drawing

Fig. 1 shows schematically an exemplary production line for producing a hydroentangled nonwoven according to the invention.

Detailed description

With reference to Fig. 1, an exemplary production line for producing a hydroentangled nonwoven according to the invention will be described. The production line is formed along an endless forming fabric 1, on which manmade cellulosic filaments 2 are laid down and through which excess air is sucked off. A resulting web 3 of manmade cellulosic filaments is advanced to a wetlaying stage 4, where a foam comprising wood pulp fibres 5 and staple fibres 6 is wetlaid on top of the web 3 and where excess water is drained off through the forming fabric 1. A resulting web comprising said manmade cellulosic filaments, wood pulp fibres and staple fibres are advanced to a hydroentangling stage 7, where the filaments and fibres are bonded to form a nonwoven 8 by action of many thin jets of high-pressure water impinging on the web and where entangling water is drained off through the forming fabric 1.

The resulting nonwoven 8 is advanced to a drying stage (not shown) where the nonwoven 8 is dried, and further to stages (not shown) for rolling, cutting, packing, etc.

According to the embodiment shown in Fig. 1, the filaments 2 are laid down directly on the forming fabric 1 where they are allowed to form a web 3.

The air used for drawing and stretching the filaments is sucked through the forming fabric 1 , to let the filaments 2 follow the air flow into the meshes of the forming fabric to be stayed there.

The speed of the filaments 2 as they are laid down on the forming fabric 1 is much higher than the speed of the forming fabric, so that the filaments will form irregular loops and bends as they are collected on the forming fabric to form a very randomized web 3.

The wood pulp fibres 5 and staple fibres 6 are slurried in a conventional way, either mixed together or first separately slurried and then mixed, and conventional papermaking additives such as wet and/or dry strength agents, retention aids and/or dispersing agents, are added, to produce a well-mixed slurry of wood pulp fibres and staple fibres in water. This mixture is pumped out through a wet-laying headbox 4 onto the moving forming fabric 1, where it is laid down on the web 3. Excess water is sucked through the web 3 of filaments 2 laid on the forming fabric 1 and down through the forming fabric, by means of suction boxes arranged below the forming fabric. The web 3 of filaments 2, wood pulp fibres 5 and staple fibres 6 is hydroentangled while it is still supported by the forming fabric 1. In the hydroentangling stage 7, the different filament and fibre types will be entangled and a composite nonwoven 8 be obtained. The entangling stage 7 can include several transverse bars with rows of nozzles from which very fine waterjets under very high pressure are directed against the web 3 to provide an entangling of the filaments and fibres. The waterjet pressure can be adapted to provide a certain pressure profile with different pressures in the different rows of nozzles. Alternatively, or subsequently, the web 3 may be transferred to a separate entangling fabric (not shown) were (further) entangling occurs.

The drying stage (not shown) may be performed on conventional web drying equipment, preferably of the types used for tissue drying, such as through-air drying or Yankee drying. The material is after drying normally wound into mother rolls before converting. The material is then converted in known ways to suitable formats and packed.

The invention is not limited to embodiments or examples shown in the drawings or described herein but may be further modified within the scope of the claims.

Example

Nonwovens were prepared in a Formette sheet former by foam forming of wood pulp (Supersoft® Plus Fluff Pulp, a southern softwood fluff from International Paper), or a dispersion of wood pulp and lyocell staple fibres (1.7 dtex), onto a web of solution- blown lyocell filaments. Different contents of lyocell staple fibres of different lengths were applied to three different webs of solution-blown lyocell filaments, as set out in Tables 1 , 2 and 3 respectively.

The nonwovens were subsequently hydroentangled with 10 manifolds/jet strips on one side of the web with 120 bars with entanglement nozzles hole diameter 120 pm with a pitch of 0.8 mm between holes.

Basis weight (measured according to NWSP 130.1. RO (15)) and thickness (measured according to NWSP 120.6 R0 (15)), as well as dry and wet tensile properties (measured according to NWSP 110.4 R1 (22), 50 mm wide strip, clamp distance 50 mm, constant-rate-of-extension, testing speed 100 mm/min, for wet tensile properties wetting to saturation was applied), were obtained for the webs of solution- blown lyocell filaments and for the hydroentangled nonwovens, as set out in Tables 1, 2 and 3.

Tensile index as used the present description is calculated according to the following formula:

X2 - Tensile index (Nm/g)

XIMD - Tensile strength in MD (N/m)

XICD - Tensile strength in CD (N/m) gi - Basis weight (g/m²)

To facilitate evaluation of the effect of staple fibre length and staple fibre content on the strength of the nonwovens, the percent increase of dry and wet tensile properties of the nonwovens containing staple fibres were calculated in relation to the tensile properties of the nonwovens containing no staple fibres. The resulting data is presented in Tables 4 and 5. Table 1. First solution-blown web and hydroentangled nonwovens prepared Table 2. Second solution-blown web and hydroentangled nonwovens prepared

Table 3. Third solution-blown web and hydroentangled nonwovens prepared Table 4. Effect of staple fibre length on strength of nonwovens (percent increase in relation to sample containing no staple fibres)

Table 5. Effect of staple fibre content on strength of nonwovens (percent increase in relation to sample containing no staple fibres)

Claims

1. A hydroentangled nonwoven comprising manmade cellulosic filaments, natural cellulosic fibres, and manmade staple fibres, wherein the manmade staple fibres have a length of 10 to 20 mm, preferably 10 to 15 mm.

2. The hydroentangled nonwoven according to claim 1 , comprising

10 to 50 weight percent of the manmade cellulosic filaments,

20 to 85 weight percent of the natural cellulosic fibres; and

2.5 to 25 weight percent of the manmade staple fibres, the weight percentages being based on the total weight of the nonwoven.

3. The hydroentangled nonwoven according to claim 2, comprising

15 to 35 weight percent of the manmade cellulosic filaments,

40 to 75 weight percent of the natural cellulosic fibres; and

5 to 20 weight percent of the manmade staple fibres, the weight percentages being based on the total weight of the nonwoven.

4. The hydroentangled nonwoven according to anyone of the preceding claims, wherein the manmade cellulosic filaments are formed of cellulose of natural origin, preferably of natural cellulose that has not been chemically modified, more preferably of viscose or lyocell, most preferably of lyocell.

5. The hydroentangled nonwoven according to anyone of the preceding claims, wherein the manmade staple fibres are formed of polyethylene, polypropylene, polyester, polyamide, polylactide, polyhydroxyalkanoate or cellulose, preferably of polylactide, polyhydroxyalkanoate or cellulose, more preferably of cellulose.

6. The hydroentangled nonwoven according to claim 5, wherein the manmade staple fibres are formed of cellulose of natural origin, preferably of natural cellulose that has not been chemically modified, more preferably of viscose or lyocell, most preferably of lyocell.

7. The hydroentangled nonwoven according to anyone of claims 4 to 6, wherein the manmade cellulosic filaments and the manmade staple fibres are formed of natural cellulose that has not been chemically modified, more preferably of viscose or lyocell, most preferably of lyocell.

8. A wipe comprising a hydroentangled nonwoven according to anyone of claims 1 to 7.

9. The wipe according to claim 8, wherein the wipe is a wet wipe, such as a wipe further comprising a liquid formulation.

10. A method of producing a nonwoven, wherein a web of manmade cellulosic filaments is provided and natural cellulosic fibres and manmade staple fibres are wet-formed on top of said web of manmade cellulosic filaments, thus forming a fibrous web comprising said manmade cellulosic filaments, natural cellulosic fibres and manmade staple fibres, and the fibrous web is subsequently hydroentangled to form a nonwoven, wherein the manmade staple fibres have a length of 10 to 20 mm, preferably 10 to 15 mm.

11. The method according to claim 10, wherein a fibre dispersion comprising the natural cellulosic fibres and the manmade staple fibres is wet-formed on top of said web of manmade cellulosic filaments.

12. The method according to claim 10 or 11 , wherein the manmade staple fibres are foam-formed on top of said web of manmade cellulosic filaments.

13. The method according to anyone of claims 10 to 12, wherein the web of manmade cellulosic filaments is provided by extrusion of a cellulose-containing solution through a spinneret onto a moving surface, such as by solution-blowing of a cellulose-containing solution.

14. A method according to anyone of claims 10 to 13, further characterized according to anyone of claims 2 to 7.

15. A method of producing a wipe, comprising a method according to anyone of claims 10 to 14, wherein the nonwoven further is cut, perforated, micro-creped, calendered, embossed, printed and/or provided with a liquid formulation.