FIELD

The present disclosure relates to fibres for non-woven fabric and a process for their preparation.

DEFINITION

As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise: Nonwovens or nonwoven fabric refers to an assembly of fibers held together by mechanical interlocking in a random web or mat by fusing of the fibers, or by bonding with a binding medium. The fibers may be oriented in one direction or may be deposited in a random manner. This web or sheet of fibers is bonded together by one of the methods described above. Hydro-entanglement refers to a process for bonding non-woven fabrics by using fine, closely spaced and high-pressure jets of water to cause interlacing reorganizing and entangling loose bunches of fibres. Hydro-entanglement is sometimes known as spun lacing, as the arrangement of jets gives a wide variety of aesthetically pleasing effects. The uniform distribution of fibres has a direct bearing on the strength of the web or non-woven fabric. Flushability refers to the ability of a material to disintegrate in water under gentle agitation in a relatively short period of time to avoid choking in the sewer systems.

Filament refers to a fibre of continuous length. All fibres that have a practically unlimited length are considered as filaments.

Filament tow refers to a group of filaments that are arranged into a bundle, also referred to as a tow. A tow can be cut into the desired length to produce fibres.

Curled shortcut fibres refer to shortcut cellulosic fibres having curled shape i.e., the shortest distance between the two ends of at least 50% of the curled shortcut fibres is less than 90% of the total length of the curled shortcut fibres. BACKGROUND

The background information herein below relates to the present disclosure but is not necessarily prior art.

Non-woven fabrics are materials that are manufactured by a non-woven process by using either staple fibres or long fibres. The material used for producing non-woven fabrics such as wet wipes, needs to be biodegradable in nature as the used wipes usually end up in drains and water bodies. One of the limitations of such products is their relatively inferior flushability, which leads to inefficient disintegration in the sewer systems.

The commonly used material for wet wipes includes cellulosic pulp or materials derived therefrom. Cellulosic pulp is 100% biodegradable cellulose, which has relatively short stiff fibres with length of 2 to 3 mm, which do not easily entangle. The bond type between the fibres is hydrogen bonding which is reversible in nature. Further, the structure is relatively planar, with little or no fibre entanglement. In the absence of hydrogen bonds, a slurry of short, un-entangled biodegradable cellulose fibres exists. Hence, the fibres made from dispersible material such as viscose, lyocell, cotton, polyester, polypropylene (PP), polyethylene (PE), polylactic acid (PL A) and the like, are further added for improving the fabric wet strength and dry strength. However, the addition of these fibres can also reduce flushability. Further, the conventional shortcut fibres are obtained from well aligned tows which lead to parallel aligned shortcut fibres. In order to impart good wet tensile strength, high amounts of shortcut fibres need to be added. However, this not only adds to the cost of the fabric, but also leads to difficulty in processing during the manufacture of the non-woven fabric.

There is, therefore, felt a need for a non-woven fabric that mitigates the drawbacks mentioned hereinabove. OBJECTS

Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are as follows.

An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative. Another object of the present disclosure is to provide curled shortcut fibres.

Yet another object of the present disclosure is to provide an economical and commercially viable process for manufacturing curled shortcut fibres.

Yet another object of the present disclosure is to provide a process for making curled shortcut fibres from wet filament tow obtained during the process of viscose, modal or lyocell.

Yet another object of the present disclosure is to provide a non- woven fabric that has comparatively better wet strength, higher wet strength to dry strength ratio and comparatively better flushability.

Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY

The present disclosure envisages curled shortcut fibres for non-wovens. Each curled shortcut fibre has length in the range of 3 mm to 25 mm and denier in the range of 1.0 to 3.0. The curled shortcut fibres are made from the wet filament tow obtained during the process of manufacturing viscose, modal or lyocell. The shortest distance between the two ends of at least 50% of the curled shortcut fibres is in the range of 70% to 90% of the total length of the curled shortcut fibres. The curled shortcut fibres have a fibre-to-fibre friction in the range of 100 Nm/s to 500 Nm/s before washing and in the range of 200 Nm/s to 400 Nm/s after washing. In an embodiment, each curled shortcut fibre has length in the range of 3 mm to 25 mm.

Also envisaged is a non-woven fabric. The non-woven fabric comprises a blend of cellulosic pulp fibres and curled shortcut fibres wherein,

• the cellulosic pulp fibres are in the range of 60 wt.% to 99 wt.% of the total blend of the fabric; and · the curled shortcut fibres are in the range of 1 wt.% to 40 wt.% of the total blend of the fabric.

Preferably, the cellulosic pulp fibres have length in the range of 2 mm to 3 mm. Preferably, the curled shortcut fibres have a length in the range of 3 mm to 25 mm and denier in the range of 1.0 to 3.0. The shortest distance between the two ends of at least 50% of the curled shortcut fibres is in the range of 70% to 90% of the total length of the curled shortcut fibres.

In a further embodiment, a process for preparing the curled shortcut fibres for non-woven fabric is provided, comprising the following steps: i) obtaining a wet filament tow comprising filaments having denier in the range of 1.0 to 3.0;

ii) cutting the filaments in the wet filament tow to obtain straight shortcut fibres having a length in the range of 3 mm to 25 mm;

iii) subjecting the straight shortcut fibres to heat in a high turbulence zone comprising a mixture of steam, hot air or hot inert gases and water, at a predetermined temperature in the range of 90 °C to 100 °C to obtain a slurry of curled shortcut fibres;

iv) processing the slurry to obtain a mat of moist curled shortcut fibres;

v) treating the fibres in the mat with at least one reagent selected from the group consisting of a desulphurization agent, a bleaching agent and a surface modifier, to obtain moist curled shortcut fibres; and vi) drying the moist curled shortcut fibres at a pre -determined temperature to obtain curled shortcut fibres having length in the range of 3 mm to 25 mm and denier in the range of 1.0 to 3.0.

In an embodiment, the wet filament tow can be obtained during the conventional process of manufacturing viscose, modal or lyocell.

Preferably, in step (ii), the cutting of the wet filament tow is done by a rotary venturi cutter or a reel cutter.

In an embodiment, the process step of treating the mat comprises bleaching the fibres in the mat by using a bleaching agent followed by application of a surface modifier, prior to drying. The bleaching agent is at least one selected from the group consisting of hydrogen peroxide, sodium hypochlorite, a chlorine -free bleaching agent such as ozone, and a UV sensitive pigment. In an embodiment, when the wet filament is obtained during the process of manufacturing viscose or modal, in step (v), the fibres in the mat are treated with a desulphurization agent. The desulphurization agent is at least one selected from the group consisting of sodium hydroxide, sodium sulphide, hot water, an organic reagent, an ion exchange resin, a coagulant and/or a dispersant.

In an embodiment, the surface modifier is at least one selected from the group consisting of lubricating agent, dispersing agent and wax. Particularly, the surface modifier is at least one selected from the group consisting of polyacrylamidoalkylltrimonium chloride, guar derivatives, blend of lubricant and emulsifiers with net cationic/anionic/non-ionic character, polysiloxanes, saturated and unsaturated fatty acids based alkanolamine esterquats, fatty acid amides, alkylketene dimers dodecyl alkylammonium chloride, Alkyl EO/PO polymer, trimonium chloride compounds, trimonium methosulphates, branched alkylphenol polyethylene glycol polypropylene glycol mono ether, alkyl polyethyleneglycol ethers, polyoxyethyleneamine, cationic textile auxilaries, fatty acid amide derivatives, polypropylene terephthalate, polyether siloxane, hydrophilic polyether siloxane emulsion, and quaternary silicone. In an embodiment, the surface modifier added in step (v) is in an amount in the range of 0.01 wt.% to 1 wt. % of the mat.

Preferably, the process parameters are adjusted to obtain curled shortcut fibres that have the shortest distance between the two ends of at least 50% of the curled shortcut fibres in in the range of 70% to 90% of the total length of said curled shortcut fibres

Also envisaged is a personal care product selected from the group consisting of wipes, diapers, training pants, baby wipes, feminine care products, adult incontinence products, wound dressings, surgical caps and drapes which comprise the curled shortcut fibres described above. In an embodiment, the use of a desulphurization agent can be avoided in case the filament tow is obtained during the process of making lyocell as it is a solvent spinning process.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The present disclosure will now be described with the help of the accompanying drawing, in which: Figure 1(A) illustrates the photographic image of conventional parallel aligned shortcut fibres; and

Figure 1(B) illustrates the photographic image of curled shortcut fibres (Sample 1), in accordance with the present disclosure.

DETAILED DESCRIPTION

Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.

Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

The terminology used, in the present disclosure, is only for the purpose of explaining particular embodiments and such terminology should not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising,"“including,” and“having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.

Products such as wet wipes, are required to be biodegradable as they usually end up in drains and water bodies. They are prepared from cellulosic pulp or materials derived therefrom such as viscose, lyocell, cotton and the like. However, the conventionally manufactured wet wipes may have relatively inferior flushability, leading to inefficient disintegration in the sewer systems. Shortcut fibres made from bio-degradable material such as viscose, modal, lyocell or cotton, are added to the cellulosic pulp material for obtaining fabric having improved strength. Further, the conventional viscose shortcut fibres are obtained from well-aligned tows which lead to obtaining straight viscose shortcut fibres. The process of making such fibres involves several complications like difficulty in providing sufficient residence time to the fast-moving tow for efficient washing of the tow for removal of carbon disulphide (CS2), acid and other chemical ingredients. Thus, such processes require special hardware for washing, and sophisticated equipment for capturing exhaust air and recovering carbon disulphide released during fibre regeneration. All these aspects add to cost of manufacturing fibres.

Further, these straight aligned fibres are needed to be added in high amounts to get the requisite wet strength and wet strength-to-dry strength ratio. Flowever, this not only adds to the cost of the fabric, but also leads to difficulty in processing during the manufacture of the non-woven fabric. Parallely aligned fibres, obtained conventionally, are also susceptible to exist as bunches of unseparated fibres leading to defects or knots on the fabric.

The present disclosure envisages curled shortcut fibres for non-woven fabric and a process for preparation thereof. A non-woven fabric made using the curled shortcut fibres of the present disclosure, produced by staple fibre process, has comparatively better fabric strength, better softness, uniform distribution of fibres, lower level of defects and comparatively improved flushability, than conventional fabric prepared using parallel aligned fibres.

In one aspect, the present disclosure envisages curled shortcut fibres, wherein each fibre has length in the range of 3 mm to 25 mm and denier in the range of 1.0 to 3.0.

The curled shortcut fibres can be made from, but are not limited to, viscose. The curled shortcut fibres can also be made from the wet filament tow obtained from the process of manufacturing modal or lyocell.

The curled shortcut fibres have a curled shape, wherein the shortest distance between two ends of at least 50% of the curled shortcut fibres is in the range of 70% to 90% of the total length of the curled shortcut fibres.

The curled shortcut fibres have a fibre-to-fibre friction in the range of 100 Nm/s to 500 Nm/s. In an embodiment, the curled shortcut fibres have a fibre-to-fibre friction in the range of 200 Nm/s to 400 Nm/s. After washing, the curled shortcut fibres have fibre-to- fibre friction in the range of 100 to 500 Nm/s. In an embodiment, after washing, the fibre-to-fibre friction is in the range of 200 - 400 Nm/s.

The fibre-to-fibre friction is an important criterion. A relatively lower value of fibre-to-fibre friction (or cohesion) indicates relatively higher lubrication that allows relatively improved movement for better dispersion in water (for wet-laid processes) or better separation (for dry processes including air-laid/carding). However, it is required that the friction should be high after production of the fabric by methods such as hydro-entanglement.

By using the process of the present disclosure, the friction behaviour can be tuned for better dispersibility in water with choice of specific fibre soft finish and its amount.

The material of the curled shortcut fibres can be, but is not limited to, viscose, modal and lyocell.

In another aspect, the present disclosure provides a non-woven fabric comprising cellulosic pulp fibres in an amount in the range of 60 wt.% to 99 wt.% of the blend and curled shortcut fibres in an amount in the range of 1 wt.% to 40 wt.% of the blend.

The curled shortcut fibres have a length in the range of 3 mm to 25 mm and denier in the range of 1.0 to 3.0.

In an embodiment, the length of the cellulosic pulp fibres is in the range of 2 mm to 3 mm.

The material of the curled shortcut fibres can be, but is not limited to, viscose, modal or lyocell.

The curled nature of the curled shortcut fibres leads to improved properties of the non-woven fabric, such as comparatively better fabric strength, better softness, uniform distribution of fibres, lower level of defects and improved flushability, than the fabric prepared by using conventional parallel aligned shortcut fibres. The curled cellulosic fibres of the present disclosure can be suitably used for making products requiring cellulose fibres that are substantially wet stable, such as disposable absorbent products including, but not limited to, personal care products, such as diapers, training pants, baby wipes, feminine care products, adult incontinence products, and medical products such as wound dressings, surgical caps or drapes. They can also be used for semi-disposable items.

In yet another aspect, the present disclosure also provides a process for preparing curled shortcut fibres. The process comprises the following steps:

(i) obtaining a wet filament tow comprising filaments having denier in the range of 1.0 to 3.0;

(ii) cutting the filaments in the wet filament tow to obtain straight shortcut fibres having a length in the range of 3 mm to 25 mm;

(iii) subjecting the straight shortcut fibres to heat in a high turbulence zone comprising a mixture of steam (or other gas like air/nitrogen etc.) and water, at a temperature in the range of 90 °C to 100 °C to obtain a slurry of curled shortcut fibres;

(iv) processing the slurry to obtain a mat;

(v) treating the fibres of the mat with at least one reagent selected from the group consisting of a desulphurization agent, a bleaching agent and a surface modifier, to obtain a mat containing moist curled shortcut fibres; and

(vi) drying the fibres of the mat at a pre-determined temperature to obtain curled shortcut fibres having length in the range of 3 mm to 25 mm and denier in the range of 1.0 to 3.0.

The material of the filaments can be, but not limited to, viscose, modal or lyocell.

In an exemplary embodiment, the step of obtaining the viscose filament tow is done by extrusion of the viscose dope through spinnerets into a spinning bath comprising 70 g/litres to 140 g/litres of sulfuric acid, 8 g/litres to 50 g/litres of zinc sulphate and 100 g/litres to 360 g/litres sodium sulphate. The filaments so obtained are withdrawn from the bath, passed over stretch bath and stretch rollers to achieve a stretch of 35% to 100%, to obtain obtain the viscose filament tow. The spinning speed is maintained at 30 m/min to 75 m/min.

The step of cutting the filaments of the wet filament tow can be done by any one equipment including, but not limited to, rotary venturi cutter and reel cutter.

In one embodiment, the step of cutting the tow is done by using a rotary venturi cutter. The cutter is made of a rotor having arms mounted with blades, wherein the rotating action of the cutter blades cuts the tow. The tow is fed into the cutter using a venturi funnel operated with soft water, wherein the venturi helps to keep the tow straightened for achieving accurate cutting, to obtain the straight shortcut fibres.

In another embodiment, the step of cutting is done by using a reel cutter, which uses a reel made of two discs mounted together and separated apart by tie pins. The peripheries of the discs are mounted with blades parallel to each other with the sharp edge facing outward. As the reel rotates, tow is wrapped around the reel and blade tips. A pressure roller wheel is fixed in position close to the blade tips such that the wheel forces the fibre against the blade tips thus cutting the fibre to obtain the straight shortcut fibres. The cut fibre passes through the opening between the blades and falls from the centre. The tow is washed during the stage of stretching with hot water, using the cutter and then optionally squeezed to help washing of the acid being carried with the tow. The washed tow is squeezed for reducing the acid content of the tow to less than 5 %. It is to be noted that, wet viscose fibres (tow) tend to form hard deposits which can adversely impact performance of the cutter. It is obvious for a person skilled in the art to perform various modifications in the design of the cutter to improve the performance and reliability of the cutter.

Other suitable equipment for cutting the fibres can also be used.

In one embodiment of the disclosure, the cut fibres are introduced in a high turbulent zone where the fibres are subjected to heat by a mixture of steam, hot air or hot inert gases and water at a predetermined temperature. The turbulent zone causes the fibres to curl. Other methods can also be used to curl to the straight shortcut fibres.

The predetermined temperature is at least 90 °C. In an embodiment, the predetermined temperature is 90 °C to 100 °C. In an exemplary embodiment, the predetermined temperature is 92 °C.

The curled fibres obtained from the high turbulent zone are received in the form of slurry. The slurry is squeezed to remove some of the water and to obtain a mat.

In a preferred embodiment of the invention, the mat is washed with hot water repeatedly to remove impurities from the mat, while maintaining the temperature of the water between 85°C and 95°C. The mat of the curled shortcut fibres obtained from the turbulent zone can be subjected to the step of bleaching the fibres by using a bleaching agent, followed by application of a surface modifier, prior to drying.

The bleaching agent is at least one selected from the group consisting of hydrogen peroxide, sodium hypochlorite, chlorine-free bleaching agents such as ozone, a peroxide and a UV pigment.

The surface modifier can be at least one selected from the group consisting of lubricating agent, dispersing agent and wax. In particular, the surface modifier is at least one selected from the group consisting of, but not limited to, polyacrylamidoalkylltrimonium chloride, guar derivatives, blend of lubricant and emulsifiers with net cationic/anionic/non-ionic character, polysiloxanes, saturated and unsaturated fatty acids based alkanol amine esterquats, fatty acid amides, alkylketene dimers, dodecyl alkylammonium chloride, Alkyl EO/PO polymer, trimonium chloride compounds, trimonium methosulphates, branched alkylphenol polyethylene glycol polypropylene glycol mono ether, alkyl polyethyleneglycol ethers, polyoxyethyleneamine, cationic textile auxiliaries, fatty acid amide derivatives, polypropylene terephthalate, polyether siloxane, hydrophilic polyether siloxane emulsion, and quaternary silicone. Other suitable surface modifiers can also be used.

The surface modifiers are added to the fibres in the mat to give a soft finish to the fibres and prevent entanglement or static during carding or other downstream processes. The surface modifier is used in an amount in the range of 0.01 wt.% to 1 wt.% of the fibres in the mat. In an embodiment, the amount of the surface modifier added is less than 0.5 wt.% of the fibres in the mat.

The surface modifier coats the surface of the fibres and it is not impregnated within the fibres and is particularly used to give a soft finish to the fibres and therefore, to the final product in which the fibres are incorporated. For instance, the wax is added to give hydrophobicity to the fibres. The lubricating agent may be added to prevent entanglement.

The mat comprises moisture to an extent of even 120%. The firbes in the mat are then subjected to drying. The pre-determined temperature of drying the moist curled shortcut fibres is in the range of 60 °C to 120 °C to achieve the desired moisture percentage. The moisture percentage is typically 10% to 15%.

When the wet filaments are obtained during the manufacture of viscose or modal, the curled shortcut fibres mat is subjected to a desulphurization process.

The desulphurization agent can be at least one selected from the group consisting of, but not limited to, sodium hydroxide, sodium sulphide, hot water, an organic reagent, an ion exchange resin, a coagulant, a dispersant.

When the wet filament tow is obtained during the conventional process of manufacturing lyocell, in the above mentioned step (v), the mat is not to be treated with a desulphurization agent, as it is a solvent spinning process and does not involve any chemical modification with carbon disulphide. Thus, the step of desulphurization can be avoided. However, the wet filament tow is subjected to multiple washings in water baths to reduce N-methylmorpholine N-oxide (NMMO) content prior to cutting of the tow.

In an exemplary embodiment, the straight cut fibres are prepared by cutting viscose filament tow in fibre lengths ranging from 3 mm to 25 mm and then subjecting the cut fibres to high turbulence zone made up of a mixture of steam, hot air or hot inert gases and water to allow curling of the shortcut fibres, washing and carbon disulphide removal, to obtain moist curled shortcut fibres. This is followed by multiple steps of washing for impurity removal, followed by bleaching and application of surface modifier in wet state and then drying to desired moisture level to obtain curled shortcut fibres having length in the range of 3 mm to 25 mm and fibre denier in the range of 1.0 to 3.0.

In an embodiment, before washing, the fibres have a sliver width in the range of 10 to 20 cm, and after washing with excess of water have a sliver width of less than 10 cm. In an embodiment, frictional properties of fibres such as fibre-to-fibre friction, fibre-to-metal friction, and cohesion width are measured by evaluating the width of the sliver by roto ring test.

The process parameters are adjusted such that the shortest distance between the two ends of at least 50% of the curled shortcut fibres are in the range of 70% to 90% of the total length of the curled shortcut fibres. This is examined by drawing samples from the curled shortcut fibres produced and examining them through a microscope.

In an embodiment, the curled shortcut fibres are used for preparing a non-woven fabric for a variety of end use applications. In an exemplary embodiment, the non-woven fabric is a wet wipe or flushable wipe.

The non-woven fabric, prepared by using the curled shortcut fibres of the present disclosure, has the following characteristics as illustrated in Table 1 below, which is provided in comparison to a non-woven fabric made from conventionally used parallel aligned fibres.

Table 1: Comparison of fibre performance

As summarized above, the curled shortcut fibres of the present disclosure exhibit improved characteristics as compared to the conventionally used parallel aligned fibres. Further, the flushability of the non-woven fabric made by using curled shortcut fibres of the present disclosure is comparatively better than the non-woven fabric made by conventionally used parallel aligned fibres, as given in Table 2 below:

Table 2: Comparison of flushability of the conventional non-woven fabric and the non- woven fabric made from curled shortcut fibres of the present disclosure

The present disclosure provides curled shortcut fibres and a non-woven fabric prepared therefrom, which has comparatively better fabric strength, better softness, uniform distribution of fibres, lower level of defects and comparatively improved flushability, in comparison to a fabric prepared from conventionally used parallel aligned fibres. The foregoing description of the embodiments has been provided for purposes of illustration and is not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.

The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale. Experimental Details:

Experiment la: Preparation of viscose filament tow Viscose was spun to form filament tow by extrusion of viscose dope through spinnerets into a spinning bath comprising HOg/litres of sulfuric acid, lOg/litres of zinc sulphate and 340g/litres sodium sulphate. The filaments were withdrawn from the bath, passed over stretch bath and stretch rollers to achieve a stretch of 40%, wherein the spinning speed was maintained at 49m/min, to obtain a wet viscose filament tow with 1.2dpf.

Experiment lb: Preparation of curled shortcut fibres

The filaments in the wet viscose filament tow were cut to obtain straight shortcut fibres, using reel cutter method. The straight shortcut fibres were subjected to processing by treating with hot water in a high turbulence zone comprising a mixture of steam, hot air or hot inert gases and water, at 92°C for around 10 minutes, wherein the removal of carbon disulphide takes place. The moist curled shortcut fibres were squeezed to remove some amount of moisture and obtain a mat of moist of curled shortcut fibres. This was followed by hot water washing while maintaining the temperature of the water between 85°C and 95 °C, and washing in the desulphurization bath, a bleach bath and an acetic acid bath for neutralization of the alkalis used in the earlier bath. The fibre mat was then treated in a soft finish zone by a lubricating agent to obtain treated moist curled shortcut fibres. The treated moist curled shortcut fibres were dried at 110 °C for 20 minutes, to obtain curled shortcut fibres having moisture of around 10%.

Experiment lc: Preparation of Lyocell filament tow

Cellulose dope comprising N-methylmorpholine N-oxide (NMMO) was spun to form filament tow by extrusion of viscous dope solution through spinnerets at a range of temperatures around 100°C depending on the viscosity of the solution. The cellulose is regenerated after passing through an air gap into the spinning bath comprising NMMO and water mixture, which lie outside the solubility range. The filaments were withdrawn from the bath, passed over stretch bath and stretch rollers to obtain a wet lyocell filament tow with 1.2dpf.

Experiment Id: Preparation of curled shortcut fibres of Lyocell

The filaments in the wet Lyocell filament tow were cut to obtain straight shortcut fibres, using reel cutter method. The straight shortcut fibres were subjected to processing by treating with hot water in a high turbulence zone comprising a mixture of air and water, at 92 °C for around 10 minutes, wherein the removal of residual solvent (NMMO) takes place. The moist curled shortcut fibres were squeezed to remove some amount of moisture and obtain a mat of moist of curled shortcut fibres. This was followed by hot water washing, followed by a bleach bath. The fibre mat obtained was then treated in a soft finish zone with a surface modifier to obtain treated moist curled shortcut fibres. The treated moist curled shortcut fibres were dried at 110 °C for 20 minutes, to obtain curled shortcut fibres having moisture of around 10%.

The curled shortcut fibres of length of 8 mm (Sample 1) and of length of 10 mm (Sample 2) from viscose filament tow and of length of 10 mm (Sample 3) from lyocell filament tow were obtained.

The conventional parallel aligned fibres and the curled shortcut fibres of the present disclosure are illustrated in Figures 1(A) and 1(B) respectively.

Experiment 2: Preparation of fabric at bench scale

The curled shortcut fibres (Sample 1 and Sample 2) were used for manufacturing non-woven fabric at bench scale, using wet laid technique, which had fibre characteristics as shown in Table 3. A reference fabric sample was also prepared by using conventional parallel aligned fibres.

Table 3: Comparison of fibre performance at bench scale fabric making

As observed in Table 3, the fabric obtained by the bench scale method by using curled shortcut fibres of the present disclosure have improved strength in wet state and higher wet/dry strength ratio, than conventional fabric made from parallel aligned fibres.

Experiment 3: Preparation of fabric at commercial scale The curled shortcut fibres (Sample 1 and Sample 2) were used for manufacturing non-woven fabric at commercial scale, using wet laid technique, which had fibre characteristics as shown in Table 4. A reference fabric sample was also prepared by using conventional parallel aligned fibres.

The fabric obtained by commercial scale method was subjected to testing of fibre characteristics as given in Table 4.

Table 4: Comparison of fibre performance at commercial scale fabric making

As observed in Table 4, the fabric obtained by the commercial scale method by using curled shortcut fibres of the present disclosure had improved strength, in dry and wet state, as compared to the conventional fabric made from parallel aligned fibres.

The curled shortcut fibres were further subjected to the following tests: Measurement of fibre-fibre friction and Fibre-Metal friction using fibre friction test:

The fibre-to-fibre friction was measured using sledge method for friction measurement. Fibre samples were conditioned at 25 °C and 50% relative humidity before friction measurement. Carded fibre lap was then horizontally placed on a metal plate. The sledge was placed on the far end of the plate above the lap. This sledge was then pulled with 2kg weight placed on it by means of a wire which was hooked with a load cell. When the sledge moved, the fibres slide against each other and against the metal surface, hence a frictional force was developed which was measured on the load cell.

Roto-ring test:

The sliver width of the fibres was measured using the Roto ring test. Fibre sliver was formed which was used for measuring the cohesion width. It was observed that with increase in the value of sliver width the cohesion decreases and vice versa.

The friction characteristics of the samples 1, 2 and 3, before washing and after washing, are depicted in Table 5. Table 5: Friction characteristics for the fibres

Flushabilitv Test

The commercially available non-woven fabric (wet wipes) made up of parallel aligned lyocell fibres having 1.3 denier and length of 10 mm fibre was tested against the non-woven fabric (wet wipes) made from sample 1 as per experiment 3. One wipe was put in 2 litres water in a transparent acrylic cuboid mounted on a shaker. The shaker is operated at 26 rpm, wherein the time was noted when disintegration of the fabric started and ended. The results are summarized in Table 6 below. Table 6: Comparison of flushability of the conventional non-woven fabric and the non- woven fabric prepared on commercial scale from curled shortcut fibres of the present disclosure

As observed in Table 6, the fabric obtained by commercial scale method by using curled shortcut fibres of the present disclosure had improved flushability as compared to the conventional fabric made from parallel aligned fibres, especially due to the curled nature of the shortcut fibres used.

The present disclosure provides curled shortcut fibres and a non-woven fabric prepared therefrom, which has comparatively better fabric strength, better ratio of wet/dry strength, lower level of defects on the fabric and comparatively improved flushability, in comparison to a fabric prepared from conventionally used parallel aligned fibres.

TECHNICAL ADVANCEMENTS AND ECONOMICAL SIGNIFICANCE described herein above has several technical advantages including, but not limited to, the realization of curled shortcut fibres for non-woven fabric, wherein the fabric has: - comparatively better fabric strength characteristics; better softness; lower level of defects on the fabric; uniform distribution of fibres in the fabric; comparatively improved flushability; - ease of scalability and operations; and lower process costs.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein. The foregoing description of the specific embodiments so fully revealed the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

The use of the expression“at least” or“at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application. The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

ECONOMIC SIGNIFICANCE

The invention disclosed herein will contribute to the country’s economy growth by way of involvement of a new efficient and quality method of manufacturing a product. The applicant submits that the present disclosure will contribute to the country’s economy positively. The flush-ability of the final product will ensure that sewers and drains are not clogged.

The product in accordance with present invention will be in great demand in country and worldwide due to the novel technical features of the present invention. This invention is a technical advancement in the fibres for non-woven fabric. The technology in accordance with present disclosure will provide a cheaper product, saving in time of the total process of manufacture. The saving in production time will improve the productivity, and cost cutting of the product, which will directly contribute to economy of the country.

The product will contribute a new concept in the fibres for non-woven fabric and a process for their preparation. The present disclosure will replace the whole concept of non-woven fabric being used in multitude of product types such as personal care products, incontinence products, medical products since decades.