WO2013026098A1

WO2013026098A1 - Method for marking threads and fibres

Info

Publication number: WO2013026098A1
Application number: PCT/AU2012/000988
Authority: WO
Inventors: Kerry PEEK; Gerhard Frederick Swiegers
Original assignee: Datatrace DNA Pty Ltd
Current assignee: Datatrace DNA Pty Ltd
Priority date: 2011-08-23
Filing date: 2012-08-23
Publication date: 2013-02-28
Anticipated expiration: 2014-02-23
Also published as: AU2012300190A1; AU2012300190B2

Abstract

The present invention provides a method for marking thread or fibre. The thread or fibre is made to pass through a coating solution comprising particles of a marker material so as to apply the marker material to the thread or fibre (110). Thereafter, the thread or fibre is subjected to a curing process (120). Presence of the marker material is detectable even after the thread or fibre has been subjected to extreme handling conditions (130).

Description

METHOD FOR MARKING THREADS AND FIBRES TECHNICAL FIELD

The present invention relates to a method for marking threads and/or fibres with particulate taggants or marker materials in order to identify or verify the legitimacy and/or origin of items to which the threads are attached or within which the threads are incorporated. BACKGROUND

Taggants and other identification devices are commonly attached to or incorporated within items of value in order to identify ownership, legitimacy, and/or origin and to hinder theft, diversion, and/or illegal use of such items. Typical examples of such items include, but are not limited to, financial and other instruments, high-value consumer goods, documents, storage media, branded products, spirits, machinery, equipment, and the like.

A wide variety of materials may be used as taggants for such purposes, including microscopically small labels containing visual indicia, encrypted radio-frequency identification (RFID) transponders, and luminescent materials which emit unique spectroscopic signatures when illuminated with light of one or more particular wavelengths.

One class of high- value items that particularly benefit from such marking are branded textiles and textile products. Numerous brands of clothing, handbags, apparel and accessories are subject to counterfeiting and diversion each year. Taggants or marker materials may be incorporated into or onto such materials to prevent or hinder such illegal activities.

In view of the foregoing, a need exists for improved methods of marking threads and fibres for identification purposes. Another need exists for new and improved methods for incorporating taggants, such as luminescent marker materials, into or onto fibres and threads. A further need exists for new and improved methods of marking threads and fibres with taggants or marker materials that are robust and durable. Another need exists for new and improved methods of marking threads and fibres with taggants or marker materials that are compatible with existing techniques for manufacturing the fibres or threads. Ideally, the new and improved methods will be transparent to the manufacturing technique - that is, there will be no need to modify the existing manufacturing technique in any substantial way to incorporate marking of the threads and fibres.

SUMMARY

An aspect of the present invention provides a method for marking thread or fibre comprising the steps of: causing the thread or fibre to pass through a coating solution comprising particles of a marker material so as to apply the marker material to the thread or fibre; and subjecting the thread or fibre to a curing process. Presence of the marker material is detectable even after subjecting the thread or fibre to extreme handling conditions.

The marker material may possess little or no affinity for the thread or fibre.

The thread or fibre may comprise a monofilament or a plurality of filaments.

In the case of a plurality of filaments, the method may compreise the further step of twisting the plurality of filaments after the plurality of filaments has passed through the coating solution, thereby trapping the marker material particles within interstitial spacings created between the plurality of filaments when twisted.

Concentration of the marker material in the coating solution may be within the range 0.1 % to 20%. The coating solution may comprise a polymer solution, a polyamide solution, or a fluoropolymer solution.

The marker material may comprise a luminescent material and may emit

luminescence when activated by ultra-violet, visible, or infra-red light. The marker material may comprise particles of size in the range 100 nm to 100 microns, and preferably in the range of about 1-20 microns, and more preferably in the range of about 2 to 4 microns.

The method may comprise the further step of detecting presence of the marker material after the thread or fibre has been subjected to said extreme handling conditions. Such extreme handling conditions may comprise the thread or fibre being sewn into a fabric and the fabric being subjected to multiple laundry cycles. _λ

BRIEF DESCRIPTION OF THE DRAWINGS

A small number of embodiments of the present invention are described hereinafter, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a flow diagram of a method for marking thread or fibre in accordance with an embodiment of the present invention;

Figure 2 depicts a sewing thread produced by the company Coats PLC after marking in accordance with an embodiment of the present invention and sewing into white and blue cloth;

Figure 3 depicts a sail-making thread after marking in accordance with an embodiment of the present invention and sewing into red canvas;

Figure 4 depicts a common red sewing thread after marking in accordance with an embodiment of the present invention and sewing into white and blue cloth; and

Figure 5 depicts detection of luminescent markers or taggants on the thread shown in

Figure 1 using an electronic reader.

DETAILED DESCRIPTION

A small number of embodiments of methods for marking threads and/or fibres with marker materials comprising particulate taggants are described hereinafter. The skilled reader will appreciate that the embodiments described hereinafter are illustrative only and are not intended to limit the present invention in any way.

International Patent Publication No. WO2006/119561, which was published on 16 November 2006 and which has common inventors with the present application, relates to high-resolution tracking of industrial process materials using trace incorporation of luminescent markers. The contents of International Patent Publication No. WO2006/119561 is incorporated herein by reference, as if expressly set forth. A step in the manufacture of many sewing threads (and other fibres), particularly multi-filament sewing threads, is their treatment in the final step of the process with a thin polymer coating which bonds the filaments together and which finishes the thread. The coating is usually applied by a high-speed dip-coating method (i.e., the thread is caused to pass through a polymer solution in a coating bath) and is typically very thin, being less than 5 microns in thickness. The coating is, nevertheless, very robust. This robustness is required because of the highly flexible nature of sewing thread and the extreme physical conditions to which it is subjected during sewing and, later, during everyday use. These conditions include extremes of friction, abrasion, and stretching, as well as elevated and local variations in temperature, and chemical and physical attack (during everyday wear and multiple laundry cycles, for example).

The present inventors have surprisingly discovered that simply adding particulate (e.g., micro- and nano-particulate) tagging or marker materials, which have little or no affinity for the fibre/s in sewing threads (i.e., there are no attractive forces between the marker materials and the fibres - no ion-pairing, electrostatic, or other attractive chemical forces between the marker materials and the fibres), in low concentrations to the dip-coating bath used for bonding or finishing during commercial manufacture of sewing and other threads, results in remarkably robust incorporation of the particulate tagging or marker material/s within the polymer coating, The tagging or marker material/s become physically trapped within the polymer coating, and particularly within the thicker interstitial spacings that are created between the multifilament fibres when they are twisted. Despite extreme physical treatment, including abrasion, friction, stretching and multiple laundry cycles, the polymer coating substantially retains the particulate tagging or marker material/s. The tagging or marker material/s does/do not substantially interfere with any of the other processes involved in the manufacture of the sewing thread.

Figure 1 is a flow diagram of a method for marking thread or fibre in accordance with an embodiment of the present invention.

Referring to Figure 1, the thread or fibre is caused to pass through a coating solution comprising particles of marker material at step 1 10. Preferably, the marker material has little or no affinity for the thread or fibre.

At step 120, the thread or fibre is subjected to a curing process that cures the applied coating solution including particles of the marker material.

The thread or fibre may then be subjected to extreme handling conditions as described hereinbefore.

At optional step 130, presence of the marker material in or on the the thread or fibre (that may have been subjected to extreme handling conditions) is spectroscopically detected.

The thread or fibre may comprise a monofilament or a plurality of filaments. In the latter case, twisting of the multiple filaments during or after the filaments have passed through the coating solution causes some of the marker material particles to become trapped within the interstitial spacings created between the twisted filaments. This advantageously provides an additional degree of robustness and durability to the marked thread or fibre. Furthermore, the multiple filaments may be untwisted before entering or while in the coating solution bath, and may be subsequently retwisted.

In certain embodiments, the concentration of the marker material in the coating solution is within the range 0.1% to 20%.

In certain embodiments, the coating solution comprises a polyamide solution or a fluoropolymer solution.

In certain embodiments, the marker material comprises a luminescent material which emits luminescence when activated by ultra-violet, visible, or infra-red light.

In certain embodiments, the marker material comprises particles of size in the range 100 nm to 100 microns.

In certain embodiments, the marker material comprises particles of size about 1 to 20 microns.

In certain embodiments, the marker material comprises particles of size about 2 to 4 microns.

The embodiments described hereinafter in greater detail employ two different industry-standard polymer coating solutions to treat widely used threads and fibres. The coating processes employed closely resemble those routinely used for bonding and/or finishing during the conventional manufacture of threads and fibres. However, in the embodiments described hereinafter, one or more particulate luminescent spectroscopic marker materials (e.g., particulate luminescent spectroscopic marker materials) are added to the polymeric solution in the coating bath. Results of tests are also presented, which were carried out to establish whether the physical properties of the coatings (i.e., durability and resistance to friction, temperature, winding unwinding/ stretching, multiple laundry cycles, etc.) are preserved after the coated threads and fibres are subjected to extreme handling conditions.

Two separate coating baths were prepared using two different polymer coating solutions, as follows:

(i) an industry-standard polyamide coating solution (Hercosett 125, available from Hercules Inc., 1313 N. Market St., Hercules Plaza, Wilmington, DE 19894-0001 ) of the type currently used by major sewing thread

manufacturers to bond and finish their multi-filament threads, and

(ii) an industry-standard fluoropolymer coating solution (Nanotex A620,

available from Nano-tex, 2220 Livingston Street, #201 Oakland, California 94606) of the type used by manufacturers to impart stain repellent and soil release properties on their fibres, threads, and yarns.

The polymer coating solutions were diluted according to the suppliers instructions, in dilutions ranging from zero (no dilution) to 1 : 10 solution.water (i.e., a 90% dilution).

Particulate luminescent marker materials in the particle size range 2-4 microns were then included in the baths. The materials were incorporated or mixed in concentrations of 1 - 4% for two different single materials and 11% for a three-material combination (this was necessary as the individual material concentrations are additive). The marker particles employed were luminescent tracer materials typically used for brand-protection, as supplied by the company DatatraceDNA Pty Ltd of 9/19 Rodborough Road, Frenchs Forest, NSW 2086, Australia, and which are referred to herein as MARKER A (DatatraceDNA Product No. A6), MARKER B (DatatraceDNA Product No. A4), and MARKER C (DatatraceDNA Product No. A2). The coating solutions were gently agitated to prevent settlement of the taggant or tracer materials.

Three commercial sewing threads were passed through separate coating baths containing taggant or marker materials, as follows:

• Coats Gramax 03149 pink sewing thread - passed through a 90% diluted polyamide solution with marker material A added in a 1% dilution ratio;

· Off-white sail-making thread - passed through an undiluted fluorinated solution with marker material B added in a 4% dilution ratio; and

• Commercial sewing thread (red) - passed through an undiluted fluorinated solution with marker materials A, B and C added in a 11% dilution ratio. The threads were passed through the coating baths at a rate of about 5 metres per minute. However, the skilled reader will appreciate that a wide range of alternative rates may be used to pass threads and fibres through the coating bath. On emergence from a bath, the threads were treated in accordance with the recommendations of the particular coating solution suppliers. This typically involves passing the threads briefly over absorbent media and then through the path of a curing unit. A heat gun was set at a distance of 15 cm from the threads to achieve the recommended flash heating temperature for heat-ciiring the threads. The skilled reader will, however, appreciate that other curing methods may alternatively or additionally be used. For example, the threads (or fibres) may simply be cured by being exposed to ultra-violet light (UV-curing) or oxygen (air-curing). Air-curing may require a relatively longer time. After curing, the threads were wound onto spindles.

The marked sewing threads were sewn into various fabrics using domestic and industrial sewing machines. Figures 2 and 5 show sewing thread produced by the company Coats PLC sewn into white and blue cloth using a Pfaff Creative 7570 domestic sewing machine. Figure 3 shows sail-making thread sewn into red canvas using an industrial sailcloth sewing machine. Figure 4 shows common red sewing thread sewn into white and blue cloth using a Pfaff Creative 7570 domestic sewing machine.

The marked threads were tested after being sewn into the various textile fabrics using a commercially available DataTrace PI reader available from DatatraceDNA Pty Ltd of 9/19 Rodborough Road, Frenchs Forest, NSW 2086, Australia. Figure 5 includes a PI reader (authenticator) displaying the message "Code Found", thus indicating detection of the marker material incorporated in or on the Coats sewing thread. The test results are presented hereinafter in Table 1.

Table 1: Test Results using a Standard Datatrace PI Electronic Reader

As can be seen from the results in Table 1 hereinbefore, the marker materials were readily and correctly detected on all of the threads after being sewn into the various textile fabrics. The marker materials were retained by the threads even after the threads were subjected to extreme handling conditions. As can be seen in Table 1, the intensity of detection of the marker materials is expressed in 'counts'. The number of counts is a relative measure of the intensity of a particular emission. As an example, a standard flourescent light tube typically produces an intensity greater than 10,000 counts.

Attempts to remove the spectroscopically detectable marker materials by vigorously scraping or wearing them off, were unsuccessful. Furthermore, subjecting the marked threads to multiple laundry cycles, or through household or industrial sewing machines at high speed, tension, and under circumstances of maximum abrasion and friction, including sewing the threads into canvas using an industrial sail-making sewing machine, failed to cause the marker materials to be undetectable. In all cases, the covert spectroscopically- detectable marker materials were indelibly applied to the threads and could be readily detected using a Datatrace P 1 electronic reader.

The foregoing description provides exemplary embodiments only, and is not intended to limit the scope, applicability or configurations of the invention. Rather, the foregoing description of exemplary embodiments provides those skilled in the art with enabling descriptions for implementing one or more embodiments of the invention. Various changes may be made in the function and arrangement of elements arid/or features without departing from the spirit and scope of the invention as set forth in the claims hereinafter.

Claims

1. A method for marking thread or fibre, said method comprising the steps of:

causing said thread or fibre to pass through a coating solution comprising particles of a marker material so as to apply said marker material to said thread or fibre; and

subjecting said thread or fibre to a curing process;

wherein presence of said marker material is detectable even after subjecting said thread or fibre to extreme handling conditions.

2. A method according to claim 1 , wherein said thread or fibre comprises a

monofilament.

3. A method according to claim 1 , wherein said thread or fibre comprises a plurality of filaments.

4. A method according to claim 3, comprising the further step of twisting said plurality of filaments after said plurality of filaments has passed through said coating solution, thereby trapping said marker material particles within interstitial spacings created between said plurality of filaments when twisted.

5. A method according to any one of claims 1 or claim 4, wherein concentration of said marker material in said coating solution is within the range 0.1% to 20%.

6. A method according to any one of claims 1 or claim 4, wherein said coating solution comprises a polymer solution.

7. A method according to claim 6, wherein said coating solution comprises a polyamide solution.

8. A method according to claim 6, wherein said coating solution comprises a fluoropolymer solution.

9. A method according to claim 1 or claim 4, wherein said marker material comprises a luminescent material.

10. A method according to claim 9, wherein said marker material emits luminescence when activated by ultra-violet, visible, or infra-red light.

11. A method according to claim 1 or claim 4, wherein said marker material comprises particles of size in the range 100 nm to 100 microns.

12. A method according to claim 1 or claim 4, wherein said marker material comprises particles of size about 1 to 20 microns.

13. A method according to claim 1 or claim 4, wherein said marker material comprises particles of size about 2 to 4 microns.

14. A method according to claim 1 or claim 4, wherein said curing process comprises application of heat to said thread or fibre.

15. A method according to claim 1 or claim 4, comprising the further step of spectroscopically detecting presence of said marker material after said thread or fibre has been subjected to said extreme handling conditions.

16. A method according to claim 1 or claim 4, wherein said extreme handling conditions comprise said thread or fibre being sewn into a fabric.

17. A method according to claim 1 or claim 4, wherein said extreme handling conditions comprise said thread or fibre being subjected to multiple laundry cycles.

18. A method according to claim 1 or claim 4, wherein said marker material has little or no affinity for said thread or fibre.

19. A thread or fibre subjected to the method of claim 1 or claim 4.