WO2012103893A1

WO2012103893A1 - Non-wowen fabric comprising kapok, methods for producing and usages thereof

Info

Publication number: WO2012103893A1
Application number: PCT/DK2012/050042
Authority: WO
Inventors: Jeannette ALMSTRØM
Original assignee: KAPOK FABRIK ApS
Priority date: 2011-02-03
Filing date: 2012-02-01
Publication date: 2012-08-09
Also published as: DK201170062A

Abstract

This invention discloses a non-woven fabric comprising a mixture of kapok fibres and binding fibres, which said non-woven fabric forms a structure that is essentially flat with at least one layer with a first surface and with a second surface where at least part of said structure contains kapok fibres at least partially bonded to binding fibres and where at least one of said first or second surfaces has a pattern of bonding between kapok fibres and binding fibres with ripples extending in at least part of the span of said layer and in at least one direction of said one surface.

Description

Non-wowen fabric comprising kapok, methods for producing and usages thereof

Field of the Invention

This invention relates to a non-woven fabric comprising a mixture of kapok fibres and binding fibres, which said non-woven fabric forms a structure that is essentially flat with at least one layer with a first surface and with a second surface where at least part of said structure contains kapok fibres at least partially bonded to binding fibres.

Background of the Invention

Kapok (Latin: Ceiba Pentandra) is a tree that grows in tropical climates. Some species of the tree grow to become as tall as 70 m.

In the 3^rd to 4^th year, adult trees produce several hundred approximately 20 cm long fruit (seed pods). Inside, the seed pods are covered with fluffy, yellowish, shiny fibre, which resembles cotton fibre. The fibre is a mix of cellulose and lignin.

The fibre from the kapok tree is commonly know or referred to as kapok, rather than kapok fibre. The kapok fibre is the lightest natural fibre, it is 8 times lighter than cotton fibre, and is obtained from the seed pods.

The length of the kapok fibre is 2 to 4 cm. The empty cavities of the fibre contain 80 percent of air. The walls of the cavities are very thin and have numerous folds. On the outside, the kapok fibre is covered with wax. No water is required for cleaning kapok fibre (i.e. removal of seeds), while the processing of 1 kg of cotton requires 12,000 to 27,000 litres of water, depending on the growing conditions and region.

As natural resources continue to be sparse, the use of environmentally sustainable resources continues to be important. As such any replacement of one product by another to save the primary resource is important. Equally important is it when one product can replace another product and save secondary resources needed in the process to produce the product. Kapok is further advantageous in that it can be pre-processed with less water than say cotton thereby handling and processing can take place in locations where water resources are lacking, which this is of key importance on the global scale.

The kapok fibre is hydroscopic and 30 percent more buoyant than cork, kapok fibre has good insulation properties: it preserves warmth in winter and cools in summer.

The kapok fibre is odourless and mould-resistant. Since the kapok fibre contains bitter substances, it does not attract insects. This is why no pesticides are needed to grow kapoks, kapok is recommended to allergic people because the bitter substances contained in its fibre have an antibacterial and antimicrobial effect, kapok fibre does not provoke allergic reactions.

It is known that the kapok fibre is used in some fabrics.

One such example of a fabric with kapok is disclosed in US 2,464,301 in which a fabric is formed by fibres, potentially adhesive fibres, and with a surface with a pattern to provide greater porosity. More specifically, WO 2010/012734 discloses a non-woven body including a fabric, which body is formed by a mixture of fibres, which fibres are kapok fibres and non- kapok cellulose fibres.

These fabrics do make use of kapok's advantageous properties, but it has long been believed that kapok only could be used in a limited number of products due to its softness and lack of strength, and hence the use of kapok is not as widespread as it could have been.

In particular the lack of strength of non-woven fabrics comprising kapok is a problem. Object of the Invention

A desire to overcome the limited usage, partly due to common belief, of kapok fibres in fabrics or textiles in combination with experimentation, has revealed one solution to provide a strong enough fabric including kapok that allow the penetration of kapok based fabrics into existing markets.

An object of this invention is for practical purposes of using non-woven fabrics to provide a sufficiently strong non-woven fabric comprising kapok. Another real problem, and perceived troublesome to overcome, with kapok in the industry is fibre dust.

The object of the present invention is to overcome these problems.

Description of the Invention

This is achieved by the present invention, that describes a non-woven fabric comprising a mixture of kapok fibres and a binding fibres, which said non-woven fabric forms a structure that is essentially flat with at least one layer with a first surface and with a second surface where at least part of said structure contains kapok fibres at least partially bonded to binding fibres.

By bonded binding fibres is understood that said binding fibres have been activated so that the binding fibres change state so as to bond to the kapok fibres.

This activation can be a hardened as compared to unhardened binding fibres through a process of partially melting or softening followed by solidification, hardening, con- gealment or equivalents.

This activation can be the transition from a network of fine connections that collapse on the surface under pressure.

In a more general sense, the hardening of the binding fibres can be understood as an activation of binding or glueing capacities of the binding fibres. In an embodiment of the bonding a calendering press is used to provide a temperature above the activation temperature, i.e. the melting or annealing temperature of the outer part, of the binding fibre to partially melt or soften the binding fibres for engagement with the kapok fibres. This is followed by a subsequent cooling or drying either by having a cooler temperature on the calendering press or subsequent to calendering press.

I an embodiment of the bonding a calendering press is used to provide pressure to partially melt or soften the binding fibres for engagement with the kapok fibres.

In a preferred embodiment of the bonding a calendering press is used to provide a desired temperature in combination with a desired pressure as described.

Thereby it implicitly implies that the binding fibres could have been in a non-hardened state before and changed by a process that includes melting or softening the binder fibres at least partially.

Due to the hardening of the binding fibre they themselves provide increased strength. Thereby the fabric that is strong enough whilst maintaining the basic properties and advantages of using kapok.

According to an embodiment of the invention, the binding fibre is a bi-component fibre. The said bi-component fibre can have a core of polyester (PET) covered with polyeth- ylene (PE). The bi-component fibre can be a so-called "bico", "bico-fibre" or "bicom- ponent" or any equivalent fibre composition.

According to an embodiment of the invention, the wt%-ratio of kapok fibres to binding fibre is around 40-75 % kapok and 60-25 % binding fibre, correspondingly.

It is noted, that the density of the textile (dtex) for kapok is typically dtex kapok = 0.7 and for a binder fibre around dtex _bico = 1 7. The density of the binding fibre can vary. Commercially available binding fibres such as FiberVisions® Binding Fibre has a dtex _bico = 1 to 20.

According to an embodiment of the invention, the non-woven fabric is special in that, at least one of said first or second surfaces has a pattern of bonding between kapok fibres and binding fibres, which pattern varies in height perpendicular to at least part of said plane of structure.

Thereby and for a given pattern the result is an increased or varying strength according to the geometry of the pattern. In a particular embodiment the pattern is a series of parallel ripples or linear waves varying between a summit and a valley. In this case strength is achieved along the predominant direction of the summits of the ripples or linear waves. By varying the distance between the ripples or waves the strength is varied. The closer the waves or ripples, i.e. shorter wavelength, the stronger.

Such pattern can be applied to the kapok and binder mixture by a method of calendering, where the calendering press has an inverse pattern as the pattern on the non-woven fabric.

The calendering press providing pressure and temperature to the mixture of kapok and binding fibres formed as a layer.

Typically varying pressure is an obvious parameter to vary and control the pattern at a give temperature, which temperature however also is variable.

According to an embodiment of the invention, the non-woven fabric is special in that, at least one of said first or second surfaces has a pattern of bonding between kapok fibres and binding fibres, which pattern varies in density across at least part of said plane structure.

Thereby typically higher density areas will provide increased strength according to the geometry of the density pattern. In a particular embodiment the density pattern is a series of parallel ripples or linear waves varying between a summit and a valley. In this case strength is achieved along the predominant direction of said structure.

Typically varying temperature is an obvious parameter to vary and control the density pattern at a give temperature, which temperature however also is variable. Both pattern as a geometric pattern and a density pattern is generally formed in combination through a combined process of applying pressure and temperature by usage of the calendering press.

According to an embodiment of the invention, the non-woven fabric is special in that, at least one of said first or second surfaces has ripples extending in at least part of the span of said layer and in at least one direction of said one surface.

By ripples are meant wavelike formation. Typically linear waves with wave shapes varying from sinusoidal to square wave forms. The form of the calendering press pattern can include overhangs of varying forms thereby controlling strength and softness. The more square form, the less soft the non- woven fabric.

According to an embodiment of the invention, the non-woven fabric is special in that, said non-woven fabric has perforations between said first surface and second surface.

Thereby the perforations provide for easy transport through the fabric.

According to an embodiment of the invention, the non-woven fabric is special in that, said perforations are located in valleys of said ripples or said waves.

According to an embodiment of the invention, the non-woven fabric is special in that, at least one of said first or second surface is embossed. Thereby such embodiment provides information about the fabric, the maker, the producer of the fabric or information regarding the capabilities of the products formed by the fabric.

Alternatively the embossed surface carries a logo or a trademark.

It has been found that a calendered surface prepares the surface for finer and more clear embossing that are also more durable and resistant to wear and tear.

According to a method for producing a non-woven fabric, said method comprising at least the steps of:

- a step of mixing kapok fibres wt % with binding fibres wt%, followed by

- a step of carding of mixture of kapok and binding fibers, followed by

- either

- a step hydro entanglement OR

- a step of thermal bonding

for forming a formed layer, followed by

- a step of calendering said formed layer.

Thereby producing a kapok based non-woven fabric is produces that is stronger and therefore durable as a replacement product for sparse or foreseen spares natural fibres.

Thereby a producing a kapok based non-woven fabric that reduces the release of unwanted kapok fibres due to the calendering process.

The step of mixing takes place in an enclosed or semi-closed space such as a box or a chamber and is referred to as the mixing chamber.

From the mixing chamber the mixture of kapok and binding fibres are transported to the next step.

The step of carding involves the distribution of the fibres uniformly into a thin light weight structure referred to as a 'Web'. During the carding process the mixture of fibres is arranged into parallel arrays by use of rotating cylinders with fine teeth which comb the fibres. In an alternative process the mixture of fibres is arranged into layers of parallel arrays with each layer's parallellity being non-parallel the layers being i.e. cross laid.

The step of hydro entanglement involves the usage of a jet, preferably a jet of water, at high pressure, i.e. several hundred bars at present, to consolidate a web of fibres. Dur- ing the process of hydrogen entanglement, the web of fibres collapse to stick together.

The step of thermal bonding includes forming and binding the mixture of fibres together to a layered structure that will hold together. The step of calendering includes the passing of the layered fabric structure through say one or several metal rolls with a desired pattern according to needed variations in MD- strength and CD-strength.

The metal rolls are heated to have a surface temperature for contact with at least one surface of the layered fabric.

The metal rolls provide a certain pressure to the layered fabric.

The temperature and the pressure of the rolls, or in general the press, are the main fac- tors determining the calendering process step.

The speed at which the fabric passes through the press is also a parameter.

The pattern of the press or the rolls is an important free design parameter as described.

The cooling of the fabric after passing the calendering is yet another parameter determining the strength and surface characteristics of the non-woven kapok rich fabric. It is natural for the person skilled in the art to experiment and explore parameter ranges of the mentioned variables. According to a method for producing a non-woven fabric and in combination with any of said methods including at least one further step of:

- embossing said essentially plane structure OR

- perforating said essentially plane structure. Thereby and when embossing, enabling figures, information, instructions, logos etc to be embossed onto at lease on surface of the kapok base non-woven fabric in a more lasting than when not calendered.

In one embodiment the non-woven fabric is wetted or damped before the step of em- bossing.

Thereby and when perforating, enabling the fluids such as gasses or liquids to pass the kapok based non-woven fabric from one side to another site so that ventilation or drainage is possible. According to an alternative embodiment, the embossing step is integrated with the calendering step. This is done by applying whatever needed embossing tool/pattern/signature into the used calendering tool.

According to an alternative embodiment, the perforating step is integrated with calen- dering step. This is done by applying whatever needed perforating tool such as needles, pressurised air valves, pressurised water vales into the used calendering tool.

According to a method for producing a non-woven fabric and in combination with any of said methods wherein the said step of calendering of at least on surface is done by a pressure between 10 N and 100 N and at a temperature of between 90 degrees C and 190 degrees C, preferably by a pressure of around 40 N and at a temperature around 138 degrees C. According to one usage of a non-woven fabric as described or a non-woven fabric produced by a method as described, a special usage is where said non-woven fabric is used to form an article as a bed linen. According to one embodiment of a non-woven fabric used for a bed linen is a kapok non-woven fabric containing 50 % wt kapok fibres and 50 % wt binding fibres such as Bico-fibres according to the previously described products and methods with a MD between 60-200 N and preferably around 150 N and a CD between 60-200 N and preferably around 150 N.

A suitable process of producing the kapok-rich non-woven fabric involves a process step of hydro-entanglement.

A suitable pattern of the kapok bonded binding fibres is a square grid extending the bed linen. Hence the pattern gives approximately equal strength in MD and in CD.

According to another embodiment of a non-woven fabric for usage as a disposable hygiene bed linen, as known from a doctor's examination bed, stored on as a roll. In this embodiment a kapok non-woven fabric containing 50 % wt kapok and 50 % wt binding fibres such as Bico-fibres.

Having machine direction MD in the same direction as the length of the rolled-up fabric these parameters are usable: MD-strength between 60-200 N and preferably around 150 N. CD (perpendicular to the roll-out direction) is not important and can be as low as a few N, say 2-10 N.

A suitable pattern of the kapok bonded binding fibres a series of linear extending in the roll-out direction i.e. in the machine direction.

According to one usage of a non-woven fabric as described or a non-woven fabric produced by a method as described, a special usage is where said non-woven fabric is used to form an article as a diaper. According to one embodiment of a non-woven fabric used for a diaper is a kapok non- woven fabric containing 40 - 50 % wt kapok fibres and 60 - 50 % wt binding fibres such as Bico-fibres according to the previously described products and methods with a MD-strength between 10 - 20 N and preferably around 15 N and a lower CD-strength of about 5 N. The non-woven fabric is preferably perforated to allow for ventilation and drainage or passage of possible fluids.

A suitable process of producing the kapok-rich non-woven fabric involves a process step of thermal bonding as is it a simple process which drawbacks are outweighed by the fact that diapers typically are disposable.

Typically the pattern is only applied to one side of the non-woven fabric. This gives the strength and the other side remains soft and suitable for skin-contact. According to one usage of a non- woven fabric as described or a non- woven fabric produced by a method as described, a special usage is where said non-woven fabric is used to form an article as a wipe.

According to one embodiment of a non-woven fabric used for a wipe or a cloth is a kapok non-woven fabric containing 50 % wt kapok fibres and 50 % wt binding fibres such as Bico-fibres according to the previously described products and methods with a MD-strength in the order of 80 N and a CD-strength of about 40 N.

The calendering process uses a pressure of about 80 N at a temperature in the range between 90 - 140 degrees Celsius, although a temperature around 125 degrees Celsius is durable.

For disposable wipes a suitable process of producing the non-woven fabric involves a step of thermal bonding thereby having a cost and resource effective step.

Typically the non-woven kapok rich fabric is 60 g/m2 with a MD-strength around 80 N and a CD-strength around 40 N for wipes for domestic usage. However the strength and variations in strength can easily be varied up or down to facilitate usage in say heavier industry setting or in finer settings.

For non-disposable wipes a suitable process of producing the non-woven fabric in- volves a step of hydro-entanglement thereby increasing the durability of the non-woven fabric as compared to using a step of thermal bonding.

According to one usage of a non-woven fabric as described or a non-woven fabric produced by a method as described, a special usage is where said non-woven fabric is used to form an article for packing, wrapping and carrying goods.

According to one embodiment of a non-woven fabric used for wrapping or carrying goods is a kapok non- woven fabric containing 50 % wt kapok fibres and 50 % wt binding fibres such as Bico-fibres according to the previously described products and methods with a MD-strength in the order of between 200 - 300 N and a CD-strength of up to the MD-strength. The MD of the non-woven fabric will typically be aligned in the direction of the effective force, which for carrying goods is the direction of gravity.

The calendering process uses a pressure of around 80 N or more at a temperature in the range between 90 - 140 degrees Celsius, although temperatures around 140 degrees Celsius seem durable.

Typically patterns are applied to both sides of the non-woven fabric. This can be done in a single calendering process step or a double calendering process steps.

In many cases the non-woven kapok rich fabric is embossed with practical information such as date, seals, logos, weight limits or alike. A further advantage of the calendered non-woven kapok rich fabric is that it can easily be printed on with at least a dye-based inkjet printer.

According to the invention, a method of producing any of said articles for usage ac- cording to any said usage, wherein said method of producing involves a step of welding together at least part of one or two surfaces of said non-woven fabric.

Thereby before mentioned articles such as, but not excluding, bed linen, diapers, wipes, wrapping and carrying bags can be produced without the need to sew.

Description of the Drawings and Figures

The invention is in one embodiment understood according to the following drawing and figures:

Figure 1 : Processes-diagram for producing kapok fabric.

Figure 2: Prior Art - Non- woven kapok no calendaring.

Figure 3: Non-woven kapok with calendering on one side.

Figure 4: Non-woven kapok with calendering on both sides.

Figure 5: Prior Art - Non- woven kapok no calendaring.

Figure 6: Non-woven kapok with calendaring.

Figure 7: Non-woven kapok with calendaring.

Figure 8: Non- woven kapok with calendering and perforation.

Detailed Description of the Invention

Figure 1 shows a process diagram for producing a durable kapok fabric.

As a first step (1) in the process kapok fibres are mixed with binder fibres. The can be done in a mixer chamber.

As a second step (2) the mixed kapok and binder fibres are carded. In an alternative embodiment, a step of cross-laying the fibres or layers of fibres is introduced or added.

According to one embodiment, the carded fibre mixture result (2) further undergoes a process of hydro entanglement (3) followed by a carding process (4) and finally a process of embossing or perforating (5).

According to another embodiment, the carded fibre mixture result (2) further undergoes through a process of thermal bonding (6) followed by a process of carding (7) and finally a process of embossing or perforating (8).

For each example some parameters are given and supported by a graph with relative strain or stretch (Dehnung), ε-Fmax, [Δ1/1₀] on the horizontal axis and strength as a force [N] on the vertical axis.

MD is the Machine Direction and CD is the Cross Direction.

In the following examples (1 to 7) a binding fibre chosen from the ranges of properties listed below is used.

Figure 2 shows the result of the stretch test performed on a non-woven fabric considered to be prior art. A scan of the surface of the non-woven fabric is inserted top right of the stretch test. Example 1 - Prior Art.

The fibre mixture consists of 50 % wt kapok and 50 % wt binding fibres made into a non-woven fabric with a thickness of 0.51 mm and a weight of 47 g/m2 - all numbers representative of samples during process.

The non-woven fabric is in the insert seen to have a fine and relatively flat surface with no apparent pattern but traces of the fibres.

The curves in figure, representing different samples of the production, shows a breaking strength Fmax to be between approximately H O N and 140 N at a stretch ε-Fmax just under 20 %. Figure 3 shows the result of the stretch test performed on non-woven fabric according to the invention and with a pattern, here caused by a calendering, on one side. A scan of the surface of the non-woven fabric is inserted top right of the stretch test.

The figure indicates a pair of waves (W) and their preferred directions and their differ- ent orientations.

Example 2 - Invention

Using the same composition of fibre mixture as in example 1, i.e. a mixture that con- sists of 50 % wt kapok and 50 % wt binding fibres, that is made into a non-woven fabric with a thickness of 0.45 mm and a weight of 60 g/m2 - all numbers representative of samples during process.

The non-woven fabric is in the insert seen to have a pattern defining where the binding fibres have been specially activated or bonded to the kapok fibres. In this embodiment the activation or bonding is done by a process of calendering 60 N at a temperature of

degrees Celsius. The curves in the figure, representing different samples of the production, shows a breaking strength Fmax of approximately 165 N and 198 N at a stretch ε-Fmax of around 21 %. Compared to example 1, example 2 represents a stronger and more durable non- woven fabric comprising kapok at a substantial level.

Furthermore and compared to example 1, example 2 represents a non- woven fabric with at least one surface that is less dusty than example 1 and thereby easier to work with during production as well as during usage. In particular in hospitals and institutions.

Example 2 whilst having one surface with patterns that increase the strength, the second surface remains soft due to the kapok.

Figure 4 shows the result of the stretch test performed on non-woven fabric according to the invention and with a pattern, here caused by a calendering, on both sides. A scan of one surface, the other being identical, of the non-woven fabric is inserted top right of the stretch test. Example 3 - Invention

Using the same composition of fibre mixture as in example 1, i.e. a mixture that consists of 50 % wt kapok and 50 % wt binding fibres, that is made into a non-woven fabric with a thickness of 0.52 mm and a weights of 71 to 91 g/m2 - all numbers represen- tative of samples during process.

The non-woven fabric is in the insert seen to have a pattern defining where the binding fibres have been specially activated or bonded to the kapok fibres. In this embodiment the activation or bonding is done by a process of calendering 60 N at a temperature of T_cai_endering=138 degrees Celsius on both sides. The curves in the figure, representing different samples of the production, shows a breaking strength Fmax of approximately 240 N and 328 N at a stretch ε-Fmax of around 21 %. Compared to example 1 and 2, example 2 represents a stronger and more durable non- woven fabric comprising kapok at a substantial level.

Figure 5 shows the result of the stretch test performed on a non-woven fabric considered to be prior art. A scan of the surface of the non-woven fabric is inserted top right of the stretch test.

Example 4 - Prior Art

The fibre mixture consists of 60 % wt kapok and 40 % wt binding fibres made into a non-woven fabric with a thickness of 0.53 mm and a weight of 33 g/m2 - all numbers representative of samples during process.

The non-woven fabric is in the insert seen to have a fine and relatively flat surface with no apparent pattern but traces of the fibres. The curves in figure, representing different samples of the production, shows a breaking strength

to be between approximately 10 N at a stretch ε-Fmax at between 16 and 20 %.

This non-woven fabric is softer than example 1 due to the increase amount of kapok. However, the strength of this non-woven fabric is as seen very low and practically useless for many purposes.

Figure 6 shows the result of the stretch test performed on non-woven fabric according to the invention and with a pattern, here caused by a calendering, on one side. A scan of one surface, the other being identical, of the non- woven fabric is inserted top right of the stretch test.

Example 5 - Invention Using the same composition of fibre mixture as in example 4, i.e. a mixture that consists of 60 % wt kapok and 40 % wt binding fibres, that is made into a non-woven fabric with a thickness of 0.39 mm and a weights of 40 to 48 g/m2 - all numbers repre- sentative of samples during process.

The non-woven fabric is in the insert seen to have a pattern defining where the binding fibres have been specially activated or bonded to the kapok fibres. In this embodiment the activation or bonding is done by a process of calendering 40 N at a temperature of

degrees Celsius on one side.

In the machine direction (MD) the non-woven fabric is from the curves in the figure, representing different samples of the production, seen to have a breaking strength Fmax of approximately 43 N and 56 N at a stretch ε-Fmax of around 13 - 14 %.

In the cross direction (CD) the non-woven fabric is from the curves in the figure, representing different samples of the production, seen to have a breaking strength

of approximately 3 - 4 N at a stretch ε-Fmax of around 32 - 39 %. Compared to example 4, example 5 represents a stronger and more durable non-woven fabric comprising kapok at a substantial level. In example 5 the kapok-rich non-woven fabric has as larger strength in the machine direction than in the cross direction as per design or free choice. Figure 7 shows the result of the stretch test performed on non-woven fabric according to the invention and with a pattern, here caused by a calendering, on one side. A scan of one surface, the other being identical, of the non-woven fabric is inserted top right of the stretch test. Example 6 - Invention

Using the same composition of fibre mixture as in example 4 and 5, i.e. a mixture that consists of 60 % wt kapok and 40 % wt binding fibres, that is made into a non-woven fabric with a thickness of 0.50 mm and a weights of 38 to 43 g/m2 - all numbers representative of samples during process.

degrees Celsius on one side.

In the machine direction (MD) the non-woven fabric is from the curves in the figure, representing different samples of the production, seen to have a breaking strength Fmax of approximately 81 N at a stretch ε-Fmax of around 15 %.

of approximately 3 - 4 N at a stretch ε-Fmax of around 30 - 41 %.

Compared to example 4, example 5 represents a stronger and more durable non-woven fabric comprising kapok at a substantial level. In example 5 the kapok-rich non-woven fabric has as larger strength in the machine direction than in the cross direction as per design or free choice.

Increasing the pressure during the calendering process also increase the strength of the kapok rich non woven fabric enabling the fabric to be put into practical usage.

Figure 8 shows the result of the stretch test performed on non-woven fabric according to the invention and with a pattern, here caused by a calendering, on one side followed by a process of perforating. A scan of one surface, the other being identical, of the non- woven fabric is inserted top right of the stretch test.

Example 7 ^'— Invention

Using a fibre mixture that consists of 60 % wt kapok and 40 % wt binding fibres, that is made into a non-woven fabric with a thickness of 0.53 mm and a weight approximately 46 g/m2 - all numbers representative of samples during process. The non-woven fabric is in the insert seen to have a pattern defining where the binding fibres have been specially activated or bonded to the kapok fibres. In this embodiment the activation or bonding is done by a process of calendering at 50 N at a temperature of

degrees Celsius on one side.

In the machine direction (MD) the non-woven fabric is from the curves in the figure, representing different samples of the production, seen to have a breaking strength Fmax of approximately between 38 - 45 N at a stretch ε-Fmax of around 9 to 11 %.

of approximately 3 N at a stretch ε-Fmax of around 65 - 103 %. Compared to example 5, example 7 represents an almost equally strong and durable non-woven fabric comprising kapok at a substantial level, but includes the added perforations making the non-woven fabric more permeable of fluids and even particles as compared to the non- woven fabric from example 5. As such the invention is described and exemplified. A person skilled in the art will find it natural to explore parameters of pressure and temperature during the calendering process.

Likewise a person skilled in the art will be inclined to choose a pattern, whose inverse can be on the press, to be applied on at least on surface of the prepared non-woven fabric comprising kapok in such a way that the strength can be controlled or designed according to needs.

In the case where the fabric is intended for use in contact with human skin a soft surface of the fabric is desirable.

Claims

1. Non-woven fabric comprising a mixture of kapok fibres and binding fibres, which said non-woven fabric forms a structure that is essentially flat with at least one layer and with a first surface and with a second surface, where at least part of said structure contains kapok fibres at least partially bonded to binding fibres and where at least one of said first or second surfaces has a pattern of bonding between kapok fibres and binding fibres, which pattern varies in height perpendicular to at least part of said plane of structure or which pattern varies in density across at least part of said plane structure characterised in that, at least one of said first or second surfaces has a pattern of bonding between kapok fibres and binding fibres with ripples extending in at least part of the span of said layer and in at least one direction of said one surface.

2. Non-woven fabric according to claim 1, characterised in that said non-woven fab- ric has perforations between said first surface and second surface.

3. Non- woven fabric according to any of claims 1 to 2, characterised in that said perforations are located in valleys of said ripples or said waves.

4. Non- woven fabric according to any of claims 1 to 3, characterised in that at least one of said first or second surface is embossed.

5. Non- woven fabric according to any of claims 1 to 4, characterised in that the binding fibre is a bi-component fibre, which said bi-component fibre can be a core of poly- ester (PET) covered with polyethylene (PE).

6. Non-woven fabric according to any of claims 1 to 5, characterised in that the wt%- ratio of kapok fibres to binding fibre is around 40-75 % kapok and 60-25 % binding fibre, correspondingly.

7. Non- woven fabric according to any of claims 1 to 6, characterised in that the kapok a density dtex of about 0.7 and the binding fibres a density dtex between 1 to 20, and preferably a dtex of about 1.7.

8. A method of producing a non- woven fabric comprising a mixture of kapok fibres and binding fibres according to any of claims 1 to 7, which method comprises:

- a step of mixing kapok fibres wt % with binding fibres wt%, followed by - a step of carding of mixture of kapok and binding fibers, followed by

- either

- a step hydro entanglement OR

- a step of thermal bonding

for forming a formed layer, followed by

- a step of calendering said formed layer with ripples extending in at least part of the span of said layer and in at least one direction of one surface of the layer.

9. A method of producing a non-woven fabric according to claim 8 including at least one further step of:

- embossing said essentially plane structure OR

- perforating said essentially plane structure.

10. A method of producing a non-woven fabric according to any of claims 8 to 9, wherein the said step of calendering of at least one surface is done by a pressure between 10 N and 100 N and at a temperature of between 90 degrees C and 190 degrees C, preferably by a pressure of around 40 N and at a temperature around 138 degrees C.

11. Usage of non-woven fabric according to any of claims 1 to 7 or non-woven fabric produced by a method according to any of claims 8 to 10, wherein said non- woven fabric is used to form an article as a bed linen.

12. Usage of non-woven fabric according to any of claims 1 to 7 or non-woven fabric produced by a method according to any of claims 8 to 10, wherein said non- woven fabric is used to form an article as a diaper.

13. Usage of non- woven fabric according to any of claims 1 to 7 or non- woven fabric produced by a method according to any of claims 8 to 10, wherein said non-woven fabric is used to form an article as a wipe.

14. Usage of non-woven fabric according to any of claims 1 to 7 or non-woven fabric produced by a method according to any of claims 8 to 10, wherein said non- woven fabric is used to form an article for packing, wrapping and carrying goods.

15. Method of producing any of said articles for usage according to any of claims 11 to 14, wherein said method of producing involves a step of welding together at least part of one or two surfaces of said non-woven fabric.