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Publication numberEP0328320 A1
Publication typeApplication
Application numberEP19890301071
Publication date16 Aug 1989
Filing date3 Feb 1989
Priority date5 Feb 1988
Publication number1989301071, 89301071, 89301071.10, EP 0328320 A1, EP 0328320A1, EP-A1-0328320, EP0328320 A1, EP0328320A1, EP19890301071, EP89301071
InventorsPeter Wright
ApplicantCourtaulds Plc
Export CitationBiBTeX, EndNote, RefMan
External Links: Espacenet, EP Register
Security device
EP 0328320 A1
Abstract
One or more threads of a photochromic yarn are used as a security device in woven material, for example a label (1). The threads are substantially colourless when ir­radiated with visible light but are reversibly converted to a coloured state (2) when irradiated with ultraviolet light.
Images(2)
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Claims(10)
1. A security device comprising woven material containing one or more threads of photochromic yarn, the yarn being substantially colourless when irradiated with visible light and reversibly converting to a coloured state when irradiated with UV light.
2. A security device as claimed in claim 1, which is in the form of a label.
3. A security device as claimed in claim 1 or 2, wherein the photochromic yarn is woven into the woven material.
4. A security device as claimed in any preceding claim, wherein the device comprises one thread of photo­chromic yarn incorporated in the woven material.
5. A security device as claimed in any preceding claim, wherein the photochromic yarn comprises cellulose acetate fibre having photochromic compound incorporated therein.
6. A security device as claimed in claim 5, wherein the photochromic compound is a spiropyran or a spiro-­oxazine.
7. A security device as claimed in claim 5, wherein the photochromic compound is a fulgide or fulgimide.
8. The use of one or more threads of photochromic yarn as a security device in woven material, the yarn being substantially colourless when irradiated with visible light and reversibly converting to a coloured state when ir­radiated with UV light.
9. The use as claimed in claim 8, wherein the woven material is a label.
10. The use as claimed in claim 8, wherein the woven material is a textile piece good and a thread of photo­chromic yarn is woven into an edge thereof.
Description
  • [0001]
    This invention relates to a security device for use in marking articles such as goods, packages or identification cards to prove their authenticity.
  • [0002]
    The device is based on the use of photochromic com­pounds. A photochromic compound is a compound that under­goes a colour change when irradiated with light of a certain wavelength, which colour change is usually rever­sible. In general the compounds become coloured when irradiated with UV light and convert to a pale or colour­less form in visible light.
  • [0003]
    It is known to use photochromic compounds by coating them onto or incorporating them into a support such as a film or plate. For example, GB-A-1,600,615 describes coating a film with a photochromic compound and using the coated film as a means for holographic data storage.
  • [0004]
    It has also been suggested to make photochromic fibre by dyeing fibre with a photochromic dye, or by incorporat­ing photochromic compound into fibre. FR-A-1,588,282 describes a process for producing polyvinylidene chloride, polyester, polyacrylonitrile, polypropylene or polyamide fibre containing an indolino-spiropyran photochromic compound. The photochromic compound is incorporated into the spinning dope prior to spinning the fibre. Alterna­tively, the photochromic compound can be fixed to a fibre by soaking the fibre with a solution of the photochromic compound
  • [0005]
    JP-A-60-21975 describes a method for producing a photochromic fibre in which a spiropyran compound is mixed with a monomer, fibre is impregnated with the monomer and the monomer is polymerised within the fibre. It is stated that the fibre can be used for clothes, dresses, parasols and bags for special fashion effects.
  • [0006]
    JP-A-61-179399 describes the preparation of a photo­chromic fibre by causing photochromic transition metal acids to adhere to or be impregnated into various fibres, and reacting the resulting product with a water-soluble condensation resin or polymerisation resin. The fibres can be used as a raw material for the production of security paper or confidential documents.
  • [0007]
    The present invention is a novel application of photochromic compound for security purposes and accordingly provides a security device comprising woven material containing one or more threads of photochromic yarn, the yarn being substantially colourless when irradiated with visible light and reversibly converting to a coloured state when irradiated with UV light.
  • [0008]
    One suitable form of the device according to the invention is a label. The label can be attached, by way of sewing, adhering or the like, to an authentic article such as a garment, bag, towel, linen, blanket, carpet, fabric or other textile piece good, or a non-textile article, by the manufacturer. The photochromic yarn incorporated in the label is invisible under normal light conditions and so the label appears as an ordinary identification label. However, when the label is irradiated with UV light the photochromic yarn becomes coloured and is visible to the naked eye. Any article not carrying a label with a colour­able thread can be readily identified as counterfeit. After irradiation with UV light, the photochromic yarn will gradually revert to colourless under normal light condi­tions, or it can be rapidly converted back by irradiating the label with strong white light. The label then appears to be an ordinary identification label once more. UV light sources are widely available, portable and easy to use, the irradiation not normally taking longer than a few seconds. In addition the UV light does not damage the article to which the label is attached. Thus the device according to the invention provides a convenient, harmless and relative­ly inexpensive method of protecting authentic articles against counterfeiting.
  • [0009]
    In an alternative embodiment of the invention and where the authentic article to be protected is a woven article, such as a roll of fabric or other textile piece good, the photochromic yarn can be incorporated directly within the article by, for example, weaving a thread into its edge.
  • [0010]
    The photochromic yarn is preferably incorporated into the woven material of the security device by weaving. It may be incorporated as either a weft or warp yarn, but is preferably a weft yarn. The resulting material may contain any number of photochromic threads in any suitable pattern, depending upon the desired arrangement and complexity. Surprisingly it has been found that, for white or pale materials, one single thread of photochromic yarn is sufficient for yarn to be seen when the material is ir­radiated with UV light.
  • [0011]
    The photochromic yarn comprises fibre containing or treated with a photochromic compound or mixture of photo­chromic compounds. Two classes of generally suitable photo­chromic compounds are the spiropyrans and spiro-oxazines, although their properties must be checked to ensure they are colourless or near-colourless under normal light condi­tions. Examples of spiro-pyrans and spiro-oxazines that can be used include 1′,3′,3′-trimethylindolino-6-nitroben­zospiropyran, 6,8-dichloro-1′,3′,3′-trimethyl-indolinoben­zospiropyran and spiroindolinonaphthoxazine.
  • [0012]
    Other classes of suitable photochromic compounds are the fulgides and fulgimides. Examples of such compounds are described in GB-A-1,442,628, 1,464,603 and 2,170,202 and in our co-pending UK Patent Application 8830336, the disclosures of which are incorporated herein by reference.
  • [0013]
    The photochromic compound is preferably incorporated into the fibre prior to spinning, conveniently by dissolv­ing or dispersing the photochromic compound into the spinning dope or melt. Any polymeric material can be used that is capable of containing a photochromic compound and being spun into a fibre without adversely affecting the photochromic compound, and that is transparent to light having the wavelength required to convert the photochromic compound from colourless to coloured or vice versa. Examples of polymeric materials that can be spun into fibre from a spinning dope into which a photochromic compound is incorporated include cellulose acetate, acrylics, for example polyacrylonitrile or polymethylmethacrylate, polyurethanes, polycarbonates, vinyl polymers, for example polyvinylalcohol, polyvinylacetate or polyvinylchloride, and regenerated cellulose. Cellulose acetate, especially secondary cellulose acetate, is preferred. The photo­chromic compound is preferably dissolved in the spinning dope, so that it is more uniformly dispersed in the fibre formed. The photochromic fulgides, spiropyrans and spiro-­oxazines for instance are soluble in a wide range of organic solvents, for example ketones such as acetone or methylethyl ketone, esters such as ethyl acetate, aromatic hydrocarbons such as toluene, chlorinated hydrocarbons such as chloroform or methylene chloride, or ethers. They are not soluble in aliphatic hydrocarbons, are reactive to some extent with lower alcohols such as methanol and ethanol and are only sparingly soluble in water. The photochromic fulgides, spiropyrans and spiro-oxazines, for example, can readily be incorporated in an acetone-based cellulose acetate dope. The photochromic compound may be mixed directly into the spinning dope, but it is preferred first to form a solution of the photochromic compound by dissolving the compound in a little of the spinning dope solvent and then mixing this into the dope. Alternatively the photochromic compound, in particulate form, may be dispersed into the spinning dope, this being necessary, for example, when the photochromic compound is insoluble in the spinning dope, as is the case when the spinning solvent is water.
  • [0014]
    Examples of polymer melts into which the photochromic compound can be dispersed prior to spinning include poly­olefins for example polyethylene, polypropylene or copoly­mers thereof, polyesters for example polyethylene tereph­thalate, polycarbonates and polyamides.
  • [0015]
    Any conventional technique may be employed for spinning the fibre such as wet, dry, air-gap or melt spinning, although where melt spinning is carried out it is important that the temperature does not exceed that which would thermally degrade the photochromic compound.
  • [0016]
    The concentration of the photochromic compound in the resulting fibre is preferably 0.1 to 20% by weight based on the total weight of the fibre, more preferably 0.2 to 2%. Correspondingly the proportion of photochromic compound in the spinning dope is generally 0.01 to 10% by weight based on the total weight of the dope, more preferably 0.04 to 1%.
  • [0017]
    In an alternative embodiment, the photochromic fibre may have a core-sheath structure, the photochromic compound being incorporated in the sheath component. The polymeric material of the sheath component may be the same or dif­ferent from the polymeric material of the core component.
  • [0018]
    The woven material that comprises the security device may be woven from any suitable textile yarn, for example cellulose acetate, viscose, solvent-spun cellulose, cotton, wool, silk, nylon, polyester or acrylic yarn or a mixture thereof. Cellulose acetate or polyester is generally preferred.
  • [0019]
    The invention will now be illustrated by the following Examples and with reference to the accompanying drawings in which:
    • Figures 1A and 1B show a label before and after irradiation with UV light; and
    • Figures 2A and 2B show an alternative label before and after irradiation with UV light.
  • [0020]
    Irradiation with UV light was carried out using a 125W mercury arc lamp (Phillips HPR 125W) transmitted through a 3mm thick, 300-400mm band pass filter (Schott glass UG1). Irradiation with white light was carried out using a 375W photoflood lamp (Phillips PF215) transmitted through a 3mm thick, 420mm cut-off filter (Schott glass GG420).
  • Example 1
  • [0021]
    A solution of photochromic compound was first prepared by dissolving 5g of the fulgide alpha-2,5-dimethyl-3-­furylethylidene (isopropylidene) succinic anhydride in 50ml acetone. The mixture was stirred for 2 hours to ensure complete dissolution.
  • [0022]
    The solution was then added to 2kg of acetone-based cellulose diacetate spinning dope having the following composition:
    Dope concentration : 27.8% w/w solids
    Dope viscosity : 115 Pa s (1150 poise) at 25°C
    Water content : 3.1%
    Acetyl value of flake : 54.8
    Flake viscosity : 100 mPa s (100 centipoise) at 6% concentration
    Amount of photochromic compound : 0.25 w/w dope
    The dope was agitated by rolling for 24 hours to ensure complete mixing.
  • [0023]
    Fibre was spun from the dope using conventional dry spinning techniques. The dope was maintained at a tempera­ture of 60°C and was pumped through a 42 hole x 50 micro­metres spinneret at a rate of 12 mls/min. The fibre was spun into a drying cell having an upper cell temperature of 60°C and a lower cell temperature of 100°C and an air flow of 0.57 m³ (20 standard cubic feet) per minute. The resulting yarn was taken up at a speed of 200 m/min on a cheesewinder. Between the take-up godet and the cheese­winder the yarn was interlaced using an air jet. The resulting yarn was 167(42) (decitex 167, no. of filaments 42), and was a very pale yellow with a shiny appearance. A matt yarn can be produced by adding titanium dioxide to the spinning dope.
  • Example 2
  • [0024]
    A solution of photochromic compound was prepared by dissolving 0.4g of the spiropyran 1′,3′,3′-trimethylin­dolino-6-nitrobenzospiropyran in 50ml acetone. The mixture was shaken for 1 hour.
  • [0025]
    The solution was then added to 1.4kg of cellulose acetate spinning dope having the same composition as that described in Example 1, and blended for 24 hours by roll­ing.
  • [0026]
    A 167 (42) yarn was spun from the dope using the same spinning conditions as described in Example 1. The result­ing yarn was a very pale pink colour with a bright ap­pearance.
  • Example 3
  • [0027]
    The photochromic yarn as produced in Example 1 was woven together with a cellulose diacetate yarn known as Dicel (Registered Trade Mark), available from Courtaulds Fibres Ltd., into a fabric. The fabric had a 1 and 3 broken twill construction. The warp yarn was solely Dicel, and the weft yarn was a combination of photochromic yarn (1 over 6mm) and Dicel, each photochromic region consisting of 20 picks photochromic yarn.
  • [0028]
    The resulting fabric was slit into a number of labels measuring 40mm x 30mm. One of these labels is shown in Figures 1A and 1B. In visible light, before irradiation with UV light, the label 1 is completely white as shown in Figure 1A and the photochromic threads could not be seen. After irradiation with UV light for 20 seconds magenta-­coloured stripes 2 appeared where the photochromic yarn had been woven in, as shown in Figure 1B. The stripes were each approximately 7mm in width and ran along the length of the label 1 in the weft direction. Subsequent irradiation with white light for 30 seconds caused the photochromic compound to revert to its near colourless form and the magenta stripes 2 disappeared, the label 1 again having the plain white appearance as shown in Figure 1A.
  • Example 4
  • [0029]
    The photochromic yarn as produced in Example 1 was woven into a fabric as described in Example 3 except that the weft yarn was a combination of photochromic yarn (1 over 50mm) and Dicel, and each photochromic region con­sisted of only one single pick of photochromic yarn.
  • [0030]
    The resulting fabric was slit into a number of labels measuring 50mm x 30mm. One of these labels is shown in Figures 2A and 2B. In visible light, before being ir­radiated with UV light, the label 10 appears completely white. After irradiation with UV light for 20 seconds the photochromic thread was clearly seen as a single magenta-­coloured line 12 against the white background as shown in Figure 2B. After subsequent irradiation for 30 seconds with white light the magenta line disappeared and the label once more was completely white.
  • Example 5
  • [0031]
    The photochromic yarn as produced in Example 2 was woven into a fabric and the fabric slit into labels as described in Example 4.
  • [0032]
    After irradiation of a label with UV light the single photochromic thread was clearly seen as a purple line against a white background. After subsequent irradiation with white light the photochromic compound reverted to its near colourless state and the photochromic thread was no longer visible.
  • Example 6
  • [0033]
    The photochromic yarn as produced in example 1 was woven together with polyester yarn into a fabric. The warp was solely 76 (24) polyester and the weft was a combina­tion of 167 (30) polyester with 4 picks of the photochromic yarn inserted every 200mm.
  • [0034]
    After irradiation of the fabric with UV light for 30 seconds magenta-coloured stripes appeared, each measuring approximately 2 mm in width. After subsequent irradiation with white light for 20 seconds the photochromic compound reverted to its near colourless state and the stripes were no longer visible.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
EP0169750A1 *11 Jun 198529 Jan 1986Michel JalonLuminescent security fibres; security documents and other materials containing these fibres
FR1588282A * Title not available
GB423281A * Title not available
GB1600615A * Title not available
JPS61179399A * Title not available
Non-Patent Citations
Reference
1 *WPIL FILE SUPPLIER, no. 86-249926/38, Derwent Publications Ltd, London, GB; & JP-A61 179 399 (OKURASHO INSATSU KY) 12-08-1986
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
EP0488902A1 *29 Nov 19913 Jun 1992Arjo Wiggins S.A.Security document including a security element having photochromic properties
EP0621574A1 *15 Apr 199426 Oct 1994Nakamura Label Co. Ltd.Forgery-preventing textured or printed emblem
EP0798415A3 *1 Feb 19973 Jun 1998Hueck Folien GmbH & Co. KGFlat textile element
EP0919650A1 *11 Nov 19982 Jun 1999Rinke Etiketten Karl Rinke GmbH & Co. KGWoven strip, particularly label strip, and method of manufacturing and using the same
EP1019574A1 *4 Sep 199819 Jul 2000Nocopi Technologies, Inc.Authenticating a textile product
EP1019574A4 *4 Sep 19982 Jan 2003Nocopi Int IncAuthenticating a textile product
EP1533406A1 *21 Nov 200325 May 2005Sulzer Markets and Technology AGMethod for producing a fabric and inspection method for verifying the authenticity of the fabric
US5289547 *6 Dec 199122 Feb 1994Ppg Industries, Inc.Authenticating method
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US5824393 *26 Oct 199520 Oct 1998Nakamura Label Inc.Forgery-preventing textured emblem
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US928069610 Sep 20158 Mar 2016Copilot Ventures Fund Iii LlcAuthentication method and system
US93630838 Aug 20067 Jun 2016Copilot Ventures Fund Iii LlcAuthentication method and system
US981167122 Jan 20167 Nov 2017Copilot Ventures Fund Iii LlcAuthentication method and system
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WO1999014416A1 *4 Sep 199825 Mar 1999Nocopi Technologies, Inc.Authenticating a textile product
WO2000073559A1 *27 Apr 20007 Dec 2000Textilma AgMethod of producing labels with an invisible barcode on a weaving machine and label produced using such a method
WO2002082383A2 *5 Dec 200117 Oct 2002Ambalux CorporationDetection method and apparatus
WO2002082383A3 *5 Dec 20011 Apr 2004Ambalux CorpDetection method and apparatus
WO2016199173A1 *10 Jun 201615 Dec 2016Council Of Scientific & Industrial ResearchNovel spiropyran based composition and application thereof as security tag
Classifications
International ClassificationD06Q1/00, D06H1/00, G09F3/02
Cooperative ClassificationD06Q1/00, G09F3/0294, D06H1/00
European ClassificationG09F3/02D3, D06Q1/00, D06H1/00
Legal Events
DateCodeEventDescription
16 Aug 1989AKDesignated contracting states:
Kind code of ref document: A1
Designated state(s): AT BE CH DE ES FR GB GR IT LI LU NL SE
3 Oct 199018DDeemed to be withdrawn
Effective date: 19900217