Source: https://patents.google.com/patent/US20070206249
Timestamp: 2018-04-27 01:15:44
Document Index: 714239388

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60']

US20070206249A1 - Security Devices Incorporating Optically Variable Adhesive - Google Patents
Security Devices Incorporating Optically Variable Adhesive Download PDF
US20070206249A1
US20070206249A1 US11682059 US68205907A US2007206249A1 US 20070206249 A1 US20070206249 A1 US 20070206249A1 US 11682059 US11682059 US 11682059 US 68205907 A US68205907 A US 68205907A US 2007206249 A1 US2007206249 A1 US 2007206249A1
US11682059
US8164810B2 (en )
A structure for providing an optical effect comprises a first and second substrates hot stamped together by an adhesive. The adhesive comprises an energy activated binder having a plurality of particles distributed therein or thereon for providing the optical effect detectable through the first substrate.
The present application claims priority from U.S. Provisional Application No. 60/744,842 filed on Apr. 14, 2006; U.S. Provisional Application No. 60/779,484 filed on Mar. 6, 2006; U.S. Provisional Application No. 60/832,826 filed on Jul. 24, 2006; and U.S. Provisional Application No. 60/861,608 filed on Nov. 29, 2006. All patents and patent applications mentioned heretofore and hereafter are incorporated herein by reference, for all purposes.
This application is related to U.S. patent application Ser. No. 11/273,985 filed Nov. 15, 2005, which is a continuation-in-part application of U.S. patent application Ser. No. 10/666,318 filed on Sep. 18, 2003, now U.S. Pat. No. 6,987,590 issued on Jan. 17, 2006 entitled “Patterned Reflective Optical Structures”; U.S. Provisional Application No. 60/673,080 filed on Apr. 20, 2005 entitled “Patterned Reflective Optical Structures”; and U.S. Provisional Application No. 60/729,907 filed Oct. 25, 2005 entitled “Patterned Optical Structures With Enhanced Security Feature” which are all incorporated herein by reference for all purposes.
This invention relates generally to hot-stamping and more particularly, to the hot-stamping of an optical device with a hot-stamp adhesive having optical effect flakes to a substrate or article.
The term Chromagram used hereafter is meant to include optical structures that have a patterned or windowed substrate together with special effect coatings or layers supported by or supporting the patterned or windowed substrate. Chromagrams of various designs are described in US Patent Application Publication No. 2006/0285184, and used as security devices or for enhancing the security of products and for their aesthetic appeal.
By use of the term “patterned” layer, it is meant that a reflective, opaque, or partially transmissive layer is applied over a substrate which may be planar or have a surface relief pattern therein, in a manner that forms a desired “pattern” or design. By way of non-limiting examples, the patterned reflective layer can be formed in the shape of letters, numerals, bar codes and/or graphical or pictorial designs.
Although not limited thereto, this invention primarily relates to types of Chromagrams, made with optical and, or, magnetic effect hot stamp adhesive having flakes and/or colorant therein. Heretofore, a desirous quality of adhesives used to bond two substrates together, wherein one substrate is to be seen through the other, has been for the adhesive to be substantially transparent and having required bonding properties. Therefore the goal has been to have an adhesive that “appears” to be as invisible as possible, and substantially matched in refractive index to the substrates with which it is bonding, thereby substantially un-affecting light passing therethrough.
It is an object of this invention to provide a hot stamp adhesive, that has therein, special effect flakes, and wherein the flakes can be seen through one or more layers the adhesive is bonding. It was not anticipated that acceptable adhesion would result when optically variable pigment was added to the hot stamp adhesive. The adhesive could also be printed in a pattern so as to affect a patterned transfer even though a flat die would be used to make the hot stamp transfer. Printing the adhesive rather than having an image in the die of the hot stamper results in a better transferred image with higher definition without “fringe” often seen in foil type transfers. Fringe refers to the ragged edges of the foil image when hot stamped onto surface of paper, for example. The problem is evident often in the hot stamp transfer of the letter “A” where the triangle of the letter “A” is covered with foil.
Security threads have been known for some time. U.S. Pat. No. 4,186,943 to Lee describes a windowed security thread that is contained within the banknote paper. Lee uses diachronic coatings, in all-dielectric optical stack, having a symmetrical design so that the same reflected and transmitted color and color shift is seen from either side of the paper through elongate windows of the paper substrate. In one embodiment, paper is removed at various points over the embedded security thread to allow the thread to be more clearly seen. Furthermore, unfortunately, counterfeiters have at their disposal from the packaging field commercially available transparent film made from hundreds of alternating layers of polymeric films that display similar color shifting and reflection and transmission characteristics as found in '943. See http://www.ptonline.com/articles/200603fa1.html. This makes foils based on all-dielectric suspect as an anti-counterfeit system. US Patent Application Publication No. 2006/0255586 by Lazzerini describes a security device composed of holographic regions with a continuous metal layer of aluminum but with variations in its thickness. In co-pending application, WO2004014665 by Lazzerini, the method of “thinning” the deposited aluminum is by chemical etching after some areas of the aluminum are protected by a transparent ink adapted to preserve the aluminum by the attacks of acid substances. The aluminum is thinned from an optical density of 1.8, transmission of 1.6%, down to 0.7 optical density or about 20% transmission, in the “A” portion, item 3 of the '586 patent application. In other words, the aluminum is opaque in areas other than the “A” portion and only semi-transparent in the “A’ areas. The use of magnetic elements in register with the holographic elements is mentioned but does not indicate the nature of the magnetic elements. Another version of the invention uses color shifting ink between the backing layer of Polyethylene Terephtalate (PET) and the continuous aluminum metal layer. The type of color shifting ink is not defined—they could be mica based transparent color shift with angle pigments, or liquid crystal color shift inks both of which are transparent—in our invention the pigment is opaque). At any rate, Lazzerini does not teach a color shift material based on Optically Variable Adhesive (OVA), does not have color shift from both sides of the security thread, does not have covert charms, and has no-demet areas in the holographic regions and does not have magnetic elements confined within the color shift pigment.
In accordance with this invention a structure for providing an optical effect is provided, comprising a first substrate and a second substrate affixed to the first substrate by an adhesive alone, wherein the adhesive comprises an energy activated binder having a plurality of particles distributed therein or thereon for providing the optical effect detectable through the first substrate.
a) providing a first substrate having at least a first optical effect;
b) coating the first substrate with a carrier vehicle having optical effect particles therein or thereon, wherein the particles provide a second optical effect detectable through the first substrate; and
c) hot stamping the coated first substrate to a second substrate or article so that the carrier vehicle is solely used as an adhesive in the hot stamping.
FIG. 21 is a cross-sectional view of a refined “synthetic thread” wherein multiple optical effects are produced by a layered security system.
For the purpose of this application, the term “energy activated adhesive” or “energy activated binder”, means a bonding substance that requires an energy source for curing. The energy activated adhesives include, but are not limited to, hot stamp adhesives, UV activated adhesives, thermoplastic and thermoset adhesives, paint-based polymeric compositions, varnishes, and staining compositions. By way of example, an adhesive is selected from the group of: polymethacrylate, polyacrylate, polyamide, nitrocellulose, alkyd resin, polyvinyl alcohol, polyvinyl acetate, and polyurethane.
The methods of activating the adhesives include hot stamping, UV curing, applying heat, or a beam of electrons. For brevity, an energy activated adhesive, possibly with special flakes therein, is referred to as “an adhesive” hereinbelow where it does not lead to confusion.
An absorber can be a grey metal with a ratio of n/k about 1, where n is the real part of the refractive index and k is the imaginary part of the reflective index, for example Cr, Ti, or Ni, or can be a non-selective absorber across the visible spectrum like TiN, or can be a cermet, as described in the article entitled “Influence of Nanosized Metal Clusters on the Generation of Strong Colors and Controlling of their Properties through Physical Vapor Deposition (PVD)” by R. Domnick et al., 49th Annual Technical Conference Proceedings (2006), Society of Vacuum Coaters, incorporated herein by reference. By way of example, a cermet material comprises silver islands in a dielectric matrix.
FIG. 4 is a photograph of a portion of a Chinese note, wherein the structure shown in FIG. 2 is hot stamped to the banknote paper. This structure includes a hologram made by Hologram Industries of Paris, France, and provides color shifting effects, i.e. different colors can be seen from different angles. For example, a square background changes its color from indigo, pointed by arrow 301, through violet—arrow 302, to hot pink color, pointed by arrow 303.
The device shown in FIG. 4 has at least five security elements: 1) a hologram with a double image—the number “25” in the center of the hologram appears at one angle and disappears at other angles, 2) an image of Venus de Milo that is easily remembered. 3) the hologram has a demetallized Al layer in a lace pattern, 4) a color shift, and 5) covert images seen at 100× or higher magnification.
In reference to FIG. 11, an additional embodiment of this invention is a structure wherein an optically variable adhesive is used to laminate two pieces of transparent PET to produce a color shifting security thread. Looking at one side of such a structure, in FIG. 11 from top down, one would see the image formed by the demet hologram and a color shift in addition to the covert images e.g. fluorescent. From the other side, one would only see a color shift if the opaque pigments were used at high concentration. For example, interference based metal-dielectric pigments at concentrations greater than 10% of pigment weight in total solids—pigment plus adhesive produce such an effect. In this embodiment, a release layer is absent, and the patterned metal layer and the covert images are optional.
Shown in FIG. 12 d, a layer of adhesive with OV particles can be used as shown in another embodiment shown in FIG. 2 d. This embodiment is similar to shown in FIG. 12 b in many respects, however has a first substrate, preferably made of PET, coated with a color shifting flakes 235 in a carrier 234, an adhesive or acrylic- or urethane-based ink, hot stamped to the same upper structure as in FIG. 12 b. After the ink has dried and cured, thus forming a color shifting coating, a hot stamp adhesive 230 is applied and cured. To form a Chromagram the coated first substrate having the hot stamp adhesive 230 is bonded with a second substrate covered with the same layers as in the embodiment shown in FIG. 12 b.
In another embodiment shown in FIG. 12 c, covert flakes 245 bearing indicia that cannot be seen with the unaided eye are mixed into the hot stamp adhesive 240 and are used to bond the two structures together as in the previous embodiments. In this embodiment both color shifting effects that can be seen though the windows where the Al coating is missing and with magnification the covert flakes 245 can be seen and serve as a means of authentication. Instead of covert flakes, optically variable flakes could be used at low concentrations so that the OV foil colors are modified when viewing from the top.
The adhesive coating was carried out on a 10” wide solvent roll coater with 100 feet of drying oven. The adhesive was applied by reverse roll gravure.
Each of the coated web samples was evaluated for stamping performance and optical density. Hot stamp transfers were made of all the samples. The optimum stamping conditions for transfer were found to be 100° C. to 125° C., 0.5-1.0 second dwell time, using the Kenson Hot Stamp Press with the 35 mm×22 mm rectangular brass stamp. The pressure was adjusted to its lowest operational point to minimize embossing of the evaluation samples. Very little fringing was observed with any of the samples. Hot stamp transfers of each of the samples were made onto the black and white areas of Leneta cards. The transfers were made at 100° C., 1.0 sec. dwell time. Reflectance scans and color variation measurements were made over the black and white backgrounds for each transfer.
Grams of deposited pigment=0.1351465523379770×(OD coated film)+0.0591124749175451
Grams of High Red deposited per sq meter=0.135546396874281×(OD coated film)+0.05.
In Table 4 of experimental data, “Charm L” stands for Low concentration of charms and “Charm H”—for High concentration of charms.
Appl % pigment % pigment Pigment Calc % Total
Roll Feet Roll Adhesive solids in liquid in Total applied to total solids
# Coated Description formulation g/sqM ink solids web g/sqM solids Measured Comments
1 150′ Charm L 400 gams 2 0.05% 0.36% 0.0071174 12% 12%-13%
(Opaque Al Venus adhesive +
de Milo layer 400 g toluene
of US $ charms with .4 gram
applied US $ pigment
2 450′ Charm H 400 gams 1.5 0.33% 2.33% 0.0349182 12% 480.8 grams of
(Opaque Al Venus adhesive + Charm L adhesive
de Milo layer of 400 g toluene mix + 159.9 g
US $ and Euro with 2.6693 adhesive +
mixed charms total gram 159.9 grams
applied Euro + toluene + .98
$pigment US$ + 1.44Euro
3 50′ High Red .5OD 120 g high red 7.965 13.04% 33.33% 2.66 39.13%
adhesive on in 800 g
Opaque Al Venus adhesive
4 50′ High Red .8OD 350 high red 10.6 30.43% 59.32% 6.29 51.30%
5 100′ High Red .8OD 350 high red 10.63 30.43% 59.32% 6.31 51.30%
6 200′ High Red .8OD 350 high red 13.42 30.43% 59.32% 7.96 51.30%
7 200′ Blur-Red .8OD 234 g BR in 8.2 22.63% 49.37% 4.05 45.84%
adhesive on 800 g adhesive
8 230′ Blue-Red .8OD 234 g BR in 7.53 22.63% 49.37% 3.72 45.84%
9 200′ Blue-Red .4OD 70 g BR in 6.51 8.05% 22.58% 1.47 35.63%
adhesive on Low 800 g adhesive
10 120′ Blue-Red .5OD 100 g BR in 6.97 11.11% 29.41% 2.05 37.78%
11 80′ High Red .3OD See below 5.6 10.51% 29.03% 1.6257332 36.19% 37% Adhesive
adhesive on Low dilution, 166 g
density Al Venus adhesive into
de Milo 687 g (120 g
Total added Total
Start ink Total Total adhesive adhesive HR.3OD Total Total adhesive % solids
wt solids pigment solids solids Formula solids pigment solids pigment
687 268.826087 89.60869565 179.2174 39.84 308.66609 89.6086957 219.057391 29.03%
To produce the aforedescribed chips, the adhesive coated rolls were slit down the length to a width of 3.25 inches so that two rolls of hologram/OVP adhesive i.e. Chromagrams could be hot stamped two at a time. A Malahide hot stamping machine, model, E4-PK, was used to transfer the Chromagrams to poker chips made of acrylonitrile butadiene stryrene (ABS) copolymer. The die was made of silicone rubber and was set at about 375° F.
Described hereinafter are embodiments of refined “synthetic threads” wherein multiple optical effects are produced by a layered security system.
Relief structure 100, is embossed into the resin layer 106 covered with demet layer 102 a, provides a demet holographic effect and includes such features as a double image hologram, a zero order hologram, a kinegram or other imagery based on grating technology. Demet layer 102 a is patterned to provide visibility of OVA layer, when the security thread shown in FIG. 21 is viewed from the top. Layer 102 a or 102 b can be patterned with fine lines of lace-like pattern for providing an additional counterfeit feature, and/or with insignia 133 a.
An image familiar to most people, such as famous statues of David and Venus de Milo, famous buildings including Eiffel Tower and Great Wall of China, famous people like Einstein, can be incorporated as a zero order diffractive image, allowing the common person to recognize and remember the device and authenticate it by combination of the image and the associated color shift.
The thread is protected from both sides, on one side by substrate 110, and on the other—by a hardcoat/resin layer 106.
When the thread is viewed at one side, the top as shown in FIG. 21, a color shifting effect of layer 130, a double image hologram or a zero order hologram 100, a demet lace-like pattern of aluminum 102 a with indicia 133 a and covert features such as “charms”, are visible. When the thread is viewed from another side, a color shifting pattern showing the color shifting background 130 in the windows of layer 102 b, surrounded by reflective aluminum 102 b, is visible.
Another advantage of the aforedescribed thread is multiple technologies used to manufacture this thread. This makes counterfeiting difficult since the counterfeiter must have multiple skill sets to make a counterfeit. Holographic structure, optically variable pigment and demet Al on the PET could be made in separate and perhaps distant facilities and brought together at the point of currency manufacture to make the final product. The OVA weds all the components together. The idea of putting components together right before the security device is inserted into the currency paper gives added security to the device since interception of one component by during shipment gives the counterfeiting only one component of the overall device. Optionally, said prefabricated components have matching symbols, for example in the aluminum layer 102 b and in the demet hologram 100 and 102 a.
Moreover, fine lines of demet layer, such as lace-like pattern, in the hologram make it very difficult for a counterfeiter to reproduce the patterning using scissor, die cutting or even using photopolymers since precise registration is required in the demet process to align the demet patterns to the holographic features.
Dielectric a* b* L* (Δa*2 + Δb*2 + ΔL*2)
4QW@550 nm −18.16 73.908 87.96 27.4
4QW@561 nm −4.082 69.098 86.597
4QW@539 nm −31.345 70.625 88.432
6QW@550 nm −14.757 19.862 81.992 31.47
6QW@561 nm 8.58 7.272 81.033
6QW@539 nm −39.085 31.712 81.693
1. A structure for providing an optical effect, comprising a first substrate and a second substrate affixed to the first substrate by an adhesive alone, wherein the adhesive comprises an energy activated binder having a plurality of particles distributed therein or thereon for providing the optical effect detectable through the first substrate.
2. A structure as defined in claim 1 wherein the first substrate has a relief structure thereon, and wherein the optical effect provided by the plurality of particles is externally visibly detectable through the diffractive structure.
4. A structure as defined in claim 2 wherein the first substrate has a high refractive index layer disposed between the diffractive structure and the adhesive.
5. A structure as defined in claim 1 wherein one of the first and second substrates has at least one of: a thin film interference stack, a reflective coat, and a high refractive index coat, and a patterned release layer thereon.
6. An optical structure as defined in claim 1 wherein the energy activated binder is activated by one of: hot stamping, ultraviolet light, heat, and a beam of electrons.
8. A structure as defined in claim 1 wherein the effect provided by the plurality of particles is detectable by using one of: a human eye, a microscope, a magnetic sensor, UV light, and IR light.
9. A structure as defined in claim 1 wherein the plurality of particles comprises at least one of: fluorescent material particles, magnetic material particles, dye particles, up-conversion pigments, nano-particles, and transparent conductive particles, flakes having a length of at least 2 microns.
10. A structure as defined in claim 1 wherein the plurality of particles are flakes having a length of at least 2 microns, and wherein the flakes are at least one of: optically variable flakes, thin film light interference flakes, diffractive flakes, reflective flakes, light absorbing flakes, covert flakes, flakes bearing symbols or indicia, flakes that are uniform in shape, magnetic flakes, metal-dielectric flakes, all-dielectric flakes, mica based flakes, and liquid crystal based flakes.
11. An optical structure as defined in claim 1 wherein one of the first and second substrates is one of: a light transmissive substrate, an essentially transparent substrate, a PET substrate, a high refractive index coat, a protective coat, a release coat, and a piece of paper.
12. A structure as defined in claim 1 wherein the first substrate has at least one region not bound by the adhesive to the second substrate.
13. A structure as defined in claim 1 wherein the adhesive comprises a first and second adhesive sub-layers.
14. A structure as defined in claim 1 wherein the adhesive has a color variation from one sample to another of ΔE, wherein ΔE is about 5.0 or less.
a. providing a first substrate with an energy activated binder thereon, wherein the energy activated binder has a plurality of particles distributed therein or thereon for providing an effect detectable through the first substrate;
c. curing the energy activated binder by applying one of: UV light, e-beam radiation, heat, and hot stamping.
18. A method as defined in claim 16 wherein in step (a) the first substrate is covered with a first energy activated binder having first particles distributed therein or thereon, and then covered with a second energy activated binder having second particles distributed therein or thereon, and the first particles are different from the second particles.
19. A method as defined in claim 16 wherein in step (a) the energy activated binder is first applied to the first substrate and then the particles are added onto the surface of the energy activated binder.
20. A method as defined in claim 19 wherein in step (a) the added particles are covered with more of the energy activated binder.
21. A method of forming an article for providing an optical effect, comprising the steps of:
a. providing a first substrate having at least a first optical effect;
b. coating the first substrate with a carrier vehicle having optical effect particles therein or thereon, wherein the particles provide a second optical effect detectable through the first substrate; and
c. hot stamping the coated first substrate to a second substrate or article so that the carrier vehicle is solely used as an adhesive in the hot stamping.
US11682059 2006-03-06 2007-03-05 Security devices incorporating optically variable adhesive Active 2028-11-15 US8164810B2 (en)
US77948406 true 2006-03-06 2006-03-06
US74484206 true 2006-04-14 2006-04-14
US83282606 true 2006-07-24 2006-07-24
US86160806 true 2006-11-29 2006-11-29
US11682059 US8164810B2 (en) 2006-03-06 2007-03-05 Security devices incorporating optically variable adhesive
US11954332 US20080088895A1 (en) 2006-03-06 2007-12-12 Article With Micro Indicia Security Enhancement
US11954332 Continuation-In-Part US20080088895A1 (en) 2006-03-06 2007-12-12 Article With Micro Indicia Security Enhancement
US13250480 Continuation-In-Part US20120075701A1 (en) 1999-07-08 2011-09-30 Optically variable security devices
US20070206249A1 true true US20070206249A1 (en) 2007-09-06
US8164810B2 US8164810B2 (en) 2012-04-24
ID=38137322
US11682059 Active 2028-11-15 US8164810B2 (en) 2006-03-06 2007-03-05 Security devices incorporating optically variable adhesive
US (1) US8164810B2 (en)
EP (1) EP1832439B1 (en)
JP (1) JP5686495B2 (en)
KR (1) KR101388615B1 (en)
CN (1) CN101058285B (en)
CA (1) CA2580321C (en)
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KR101388615B1 (en) 2014-04-29 grant
CN101058285B (en) 2010-12-01 grant
JP5686495B2 (en) 2015-03-18 grant
EP1832439A1 (en) 2007-09-12 application
CA2580321A1 (en) 2007-09-06 application
JP2007241283A (en) 2007-09-20 application
EP1832439B1 (en) 2014-04-23 grant
CN101058285A (en) 2007-10-24 application
US8164810B2 (en) 2012-04-24 grant
KR20070091565A (en) 2007-09-11 application
CA2580321C (en) 2014-11-04 grant
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PHILLIPS, ROGER W.;MAYER, THOMAS;LAMAR, SCOTT;AND OTHERS;REEL/FRAME:019101/0585;SIGNING DATES FROM 20070227 TO 20070328
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PHILLIPS, ROGER W.;MAYER, THOMAS;LAMAR, SCOTT;AND OTHERS;SIGNING DATES FROM 20070227 TO 20070328;REEL/FRAME:019101/0585