WO2007143762A1

WO2007143762A1 - Fibre containing article

Info

Publication number: WO2007143762A1
Application number: PCT/AT2007/000259
Authority: WO
Inventors: Thomas Richard Burrow; Gert Kroner; Dieter Eichinger; Friedrich Weninger; Wilhelm Feilmair
Original assignee: Lenzing Aktiengesellschaft
Priority date: 2006-06-14
Filing date: 2007-05-30
Publication date: 2007-12-21
Also published as: TW200819565A; JP2009540140A; AT504704A1; AT504704B1

Abstract

The present invention relates to a fibre containing article having therein as a means for identification at least some man-made fibres of a reproducible unique shape, which is clearly distinguishable from the shape of the rest of the fibres contained in the article.

Description

Fibre Containing Article

Background

This invention relates to fibre containing articles and has particular reference to methods of identification of such fibre containing articles for tracing or security purposes.

The development of high value fibre containing products takes resources in respect of both development costs and marketing costs. This is particularly true in the textile field where there is a complex supply chain. There are many textile fibre materials in the market available from different suppliers which can be used to produce certain textile articles to the disadvantage of the organisation which carries out the expensive original development work. Furthermore, processing of fibre material into final textile articles comprises many different processing steps which in most cases are undertaken by different companies on a worldwide basis.

Therefore it is not an easy task to identify in either intermediate (precursor) products or the final textile articles the origin of the material or materials and the composition of these materials. This also leads to the problem that sometimes textile articles are not described properly in regard to their origin. On occasions the generic name of the fibres is used incorrectly.

Final customers in the textile chain want to be sure that specified fibre materials are properly used and that branding activities are correctly complied with. Some fibre-containing articles, such as paper, may require identification especially for security purposes. It is well known to incorporate a watermark in paper as a means of identifying the paper. Because watermarks have to be incorporated into the paper as it is produced, it makes a hurdle which has to be overcome in the event that fake paper products are manufactured. Other textile containing articles or even articles formed entirely of textile may also usefully be uniquely identifiable. For example, medical items such as swabs could usefully be made identifiable in order that a trace could be kept in the event that the medical swabs appeared in unauthorised positions. Additionally, certain textile containing products can be faked and particularly those which have a safety implication such as brake pads etc could also usefully be made identifiable.

It is known to incorporate non cellulosic matter into man made cellulosic fibres which are resistant to the processing used to convert the raw material into fibre. This means that this additional material does not change the properties of the fibre material and has no impact on processing the material.

These chemical elements or compounds have then to be detected via chemical analysis of the textile material.

A disadvantage of that approach is that the chemical analysis of the textile material can only be performed with special equipment, is expensive and takes time. Relying on this alone can therefore be problematical. It is an object of the invention to provide an article with a special set of parameters or characteristics that enables easy identification of the article. Especially an object of the invention is to provide an article containing or essentially consisting of fibre material, which is identifiable by itself, or amongst other fibre containing articles. The set of parameters is chosen in a way that identification can be performed in a simple way by many people and organisations on a cheap basis.

Statements of Invention

By the present invention there is provided a fibre containing article having therein as a means for identification at least some man-made fibres of a reproducible unique shape.

Under "reproducible unique shape", for the purposes of the present invention, a shape is understood which is clearly distinguishable from the shape of the rest of the fibres contained in the article.

The fibre containing article preferably essentially consists of fibres.

Preferably the man-made fibres with said reproducible shape are cellulosic fibres, further preferably being selected from the group consisting of viscose fibres, polynosic fibres, high wet modulus fibres or lyocell fibres. Especially preferred is an article consisting essentially of man-made cellulosic fibres, with a certain amount of man-made cellulosic fibres of a reproducible unique shape.

The article may be a textile article, such as a bale of fibre, a sliver, a yarn, a fabric, a garment or a home-textile, or may be a non-woven article, such as a web, a filling fibre, particularly for sleeping bags or bedding articles, or may be a technical article such as a fibre reinforcement, a rope, a flocked wallpaper, or may be a paper.

In a further preferred embodiment, the article is a specialty paper, especially a paper for banknotes.

The unique shaped fibre may comprise any proportion within the fibre containing article sufficient to enable it to be readily identified. Preferably the article contains at least 1% of the fibres of the unique shape, and preferably less than 10%. Further preferably, the article contains 1-5%, most preferably 1-2% of the fibres of the unique shape. The unique shaped fibres may further contain a chemical tracer, preferably one capable only of incorporation into the man-made fibres during the manufacturing process.

The fibres may be of a unique sized cross-sectional shape. For example, the fibers may be of a unique sized circular cross-sectional shape or a unique non- circular cross sectional shape. A non-circular cross-sectional shape may be produced for example by fusing cellulosic filaments immediately after extrusion or by extrusion of a suitable spinning dope through shaped spinnerette holes.

In the case of cellulosic man-made fibres there are already differences between the cross-sectional shape of the various known fiber-types per se:

For example, a standard viscose fibre exhibits a rather serrated cross-sectional shape, whilst polynosic and some special high wet modulus fibres as well as standard lyocell fibre exhibit an essentially round cross-section shape. Both cross- sectional shapes can be clearly distinguished from each other.

Therefore, admixing a certain amount of a fibre with an essentially round-cross- section to an article containing a fibre with a serrated cross-section will enable the article to be readily identified.

It is also possible that the unique shape may comprise a unique length of the fibre. Because staple fibre is normally produced by a process which involves the extrusion of a continuous tow of filaments and then cutting the tow to form staple fibre, the manufacturer of the fibre is in a unique position to create fibres of a certain length which once created cannot be faked by subsequent users of the fibre. Subsequent users could only cut the staple fibre into smaller lengths but the reality is that fibre containing articles contain millions of individual staple fibres which could not possibly be cut individually into different lengths by someone wishing to fake a design. Manufacturing man-made cellulosic fibres is a capital intensive process which requires very expensive plant and cannot be carried out cheaply by a prospective counterfeiter.

In the event that a tracer element were to be incorporated into the fibre, a coloured pigment, a fluorescent pigment, a uniquely shaped particle using micro spheres or a chemical with known reactivity or clearly divined UV or infra red spectrum could be used.

The present invention, furthermore, relates to a method for enabling identification of a fibre containing article, comprising the step of providing in said article at least some man-made fibres of a reproducible unique shape, which is clearly distinguishable from the shape of the rest of the fibres contained in the article.

Admixing of the man-made fibres with unique reproducible shape to the other fibres contained in the article according to the invention may take place in various stages of the production process.

For example, the fibres may be mixed together already during the fibre production process, such as after having been spun from the respective spinning solution. Alternatively, the fibres may be mixed together at the stage of forming a textile

article such as a yarn.

Embodiments of the Invention By way of example only, embodiments of the present invention will now be described with reference to the accompanying drawings, which are taken from US Patent 6 333 108 and which show examples of unique fibre shapes in cellulosic fibres which could not be faked without access to a viscose fibre production plant.

In the drawings:

FIGS 1 , 6 and 8 are diagrammatic representations of extrusion holes used for spinning filaments for use in the present invention; FIGS 2, 3, 5, 7 and 9 are reproductions of photomicrographs of filament cross- sections; and

FIG 4 shows the measurements taken to determine the aspect ratio of a filament limb.

Although some man-made fibres, such as polyester fibres or polypropylene fibres are produced by heating a meltable polymer and extruding it through a spinnerette, this is not the case with cellulosic fibres. Man-made fibres such as polyester and polypropylene would therefore be more readily made on a small scale (albeit given the difficulties of producing spinnerette) than would be the case for cellulosic fibres. Cellulosic fibres such as viscose fibres are produced in large, complex, manufacturing plants by processes which are well known in themselves but which cannot be reproduced very easily on a small scale to enable faking of fibres to be produced. This is also the position with lyocell fibres where again large production plants are used to manufacture the fibres for commercial use. Both the viscose process and the lyocell process are well known.

In the viscose process, cellulose is slurried with caustic soda to form an alkali cellulose which is pressed out and drained. This is pre-aged to partially depolymerise the cellulose. After pre-aging the alkali cellulose is reacted with carbon disulphide to form sodium cellulose xanthate. This in turn is dissolved in more caustic soda to form a spinning solution also known as viscose or a dope.. The dope is then ripened to permit redistribution of the xanthate groups to ease the spinning process. The ripened dope is filtered and is extruded through a spinnerette into an acidic liquid, typically containing sulphuric acid. The acid reacts with the alkali to form a sodium salt, typically sodium sulphate, and carbon disulphide is released regenerating the cellulose in the form of long filaments.

In the lyocell process cellulose is mixed with water and an organic solvent such as n-methyl morpholine N-oxide (NMMO) and the mixture is heated under a vacuum to drive off some off the water so as to cause the cellulose to go into solution in the NMMO and the remaining water mixture. This forms a dope which is extruded through a spinnerette and an air gap into a spin bath. In the spin bath the NMMO is dissolved out of the extruded filaments, so that the dissolved cellulose precipitates to form cellulose filaments.

In both cases the filaments of cellulose are passed to a suitable cutting machine to form the staple fibre which is the product preferably used in connection with the present invention. The shaped fibres may be produced by extruding the filaments through shaped spinnerette holes as shown in the drawings or they may be produced by extruding the filaments through spinnerettes having closely adjacent holes so that the filaments fuse immediately after extrusion so as to form the shaped fibres. Both the shape of the fibres and the length of the staple fibre filaments are controllable and within the production process the fibre producer can produce large numbers of different combinations which can each be sold to a unique customer to enable the production of uniquely identifiable articles in accordance with the invention.

Full details of how to prepare shaped fibres are given in US Patent 6333 108B, the contents of which are incorporated herein by way of reference. Essentially the viscose dope is spun through extrusion holes which are shaped to conform to the shape of the desired fibre. For example, viscose can be extruded through Y shaped extrusion holes as shown in Figure 1 where the three legs are arranged at 120° to one another and the limbs of each leg are 89 microns long and 25 microns wide. This produces the fibre as shown in Figures 2, 3, 5 and schematically as shown in Figure 4. Similarly the hole as shown in figure 6 produces fibres as shown in Figure 7 and the hole as shown in Figure 8 produces fibre as shown in

Figure 9.

Since the fibre production process requires large viscose fibre plants, it is not possible to produce fake fibre without a very large investment. It is possible for the fibre producer to produce fibres having different lengths of the limbs, so that the length L as shown in figure 4 can be varied either with one limb having a different length to the other two limbs or all three limbs having different lengths or all three limbs having the same length. It is also possible to alter the width W of the limbs. Furthermore, the number of limbs can be varied.

Not only can the cross sectional shape of the fibre be altered but the staple length of the fibre can be altered. Again, cutting staple fibre to a given length is only possible on a full scale production plant for e.g. viscose or lyocell fibers and is not capable of being faked without a considerable investment.

By mixing a small quantity of such a viscose cellulosic shaped fibre with regular viscose fibre, it is possible to have a product which can be processed and dyed exactly as pure viscose fibre whilst capable of easy identification simply by taking a cross section of a set of fibres either from a bale or from a yarn or from fabric or from a garment and examining them under the microscope. This means that the origin of the fibre can readily be traced which is a considerable aid to identification and in the case of certain items such as security papers to easily enable the security aspects of the product to be identified.

The following examples illustrate various embodiments of a textile article according to the present invention:

- A textile article such as a bale or a yarn, containing a mixture of 98% viscose fibre with standard (serrated) cross-sectional shape and 2% viscose fibre with a Y- or H-shaped cross-sectional shape. - A textile article such as a fibre bale of a yarn, containing a mixture of 97% modal fibre with a standard (e.g. peanut-like) cross-sectional shape and 3% modal fibre with a Y-shaped cross-sectional shape, such as disclosed in PCT/AT2005/000493 (not pre-published).

In all the above-mentioned examples, the skilled artisan can easily determine the identity of the article in question, by checking the cross-sectional shape of the fibres contained therein via microphotographs. In all cases, the minor amount of fibres with a different cross-sectional shape will clearly be recognisable.

Claims

1. A fibre containing article having therein as a means for identification at least some man-made fibres of a reproducible unique shape, which is clearly distinguishable from the shape of the rest of the fibres contained in the article.

2. An article as claimed in Claim 1 in which the man-made fibres are staple fibres.

3. An article as claimed in Claim 1 or 2 in which the man-made fibres are cellulosic fibres.

4. An article as claimed in Claim 2 in which the cellulosic fibres are selected from the group consisting of viscose fibres, polynosic fibres, high wet modulus fibres and lyocell fibres.

5. An article as claimed in any one of claims 1-4 in which the article essentially consists of fibres, preferably cellulosic fibres.

6. An article as claimed in any one of claims 1-5 in which said reproducible unique shape is selected from the group consisting of unique circular cross-sectional shapes, unique non-circular cross-sectional shapes and unique fibre staple lengths.

7. An article as claimed in any one of Claims 1-6 in which the article is a textile article.

8. An article as claimed in any one of Claims 1-6 in which the article is selected from the group consisting of non-woven articles, such as a web, a filling fibre, particularly for sleeping bags or bedding articles, technical articles such as a fibre reinforcement, a rope, a flocked wallpaper, and papers.

9. An article as claimed in claim 8, in which the article is a specialty paper, especially a paper for banknotes.

10. An article as claimed in Claim 7 in which the textile article is selected from the group consisting of a bale of fibre, a sliver, a yarn, a fabric, a garment or a home-textile.

11. An article as claimed in any one of Claims 1-10 in which the unique shaped fibres comprise 1 to less than 10%, further preferably 1-5%, most preferably 1-2% of the fibres contained in the article.

12. An article as claimed in any one of Claims 1-11 in which the fibres further contain a chemical tracer.

13. A method for enabling identification of a fibre containing article, comprising the step of providing in said article at least some man-made fibres of a reproducible unique shape, which is clearly distinguishable from the shape of the rest of the fibres contained in the article.

14. A method according to claim 13, characterized in that the unique shaped fibres comprise 1 to less than 10%, further preferably 1-5%, most preferably 1-2% of the fibres contained in the article.