Patent Application
20080145612
This invention relates to labels. In one aspect, the invention relates to tamper-evident labels while in another aspect, the invention relates to tamper-evident labels with a planar ingress solvent-indicating feature. In still another aspect, the invention relates to an electronic device bearing a tamper-evident label with a planar ingress solvent indicating feature while yet in another aspect, the invention relates to a method of visibly recording the exposure of an electronic device to solvent.
Solvents, i.e., liquid water and/or an organic solvent such as a hydrocarbon or halogenated hydrocarbon, e.g., gasoline, turpentine, chloroform, perchloroethylene, etc., can readily damage electronic devices such as laptop computers, cell phones and personal digital assistants. Accordingly, a need exists for a label or other device to indicate whether or not an electronic device has been subjected to contact with a solvent, at least sufficient solvent to void a product warranty. This need is filled to some extent by various commercially available, single-purpose labels with a format as described in
As shown in
Water enters the structure from an edge surface of the label, not a face surface or in other words, the structure is an edge ingress label. If an edge surface of the label comes in contact with liquid water, then water will wick along the paper layer dissolving the water-soluble ink beneath the paper layer. The paper layer will absorb the solubilized ink, and the ink will become visible to an observer. The clear plastic film protects the label and keeps dissolved ink from seeping to the surface of the label and contaminating the electronic device and/or marking the user's person or clothing. If, of course, an organic solvent-soluble ink replaces the water-soluble ink, then this label will detect and report contact of the label with the organic solvent, not water.
While these single-purpose labels perform as designed, a strong interest in the electronic device industry exists for a label that can perform more. For example, an unscrupulous person could remove an activated water-indicating label from a device that has been in contact with liquid water, and replace it with an unactivated water-indicating label. One label that had both water- and tamper-indicating features could report such activity. The use of separate labels for each function would not report such activity and in any event, surface space on many electronic devices is limited thus making a dual or multi-purpose label more desirable than two or more separate labels.
One approach to a dual purpose label is to attach a small solvent-indicating label to a larger tamper-indicating label, but this approach has several drawbacks. First, the solvent-indicating label takes space on an already small label, and that space could be better used for printed information, e.g., a bar code. Second, a roll of labels with non-uniform thickness is difficult to roll uniformly. Third, the thicker portion of the label creates difficulties if print is imparted to the label using thermal transfer printing. Fourth, such a label with another label creates a very thick profile and interferes with efficient packing of a battery and other components into a thin electronic device.
Better solutions and improved formats are desired for an effective label that possesses both tamper- and solvent-indicating features.
In one embodiment, the invention is a multi-layer, planar ingress tamper- and solvent-indicating label comprising a single layer of a solvent-indicating composition coated over a tamper-indicating label. The composition of the solvent-indicating label is porous to solvent, and it comprises an organic solvent-soluble binder, pigment at a concentration greater than the critical pigment-binder ratio, and dispersed solvent (typically water) soluble dye particles. The tamper-indicating label can be of any construction, e.g., frangible and difficult to remove, or easy to remove but leaving behind a pattern of adhesion, or cleanly removed but irreversibly changed.
In another embodiment, the invention is a multi-layer, planar ingress tamper- and solvent-indicating label comprising a tamper-indicating label, a composition porous to solvent and coated over the label, and an ink applied as indicia, typically in a single printing pass, over the composition. The tamper-indicating label can be of any construction, the composition comprises an organic solvent-soluble binder and pigment at a concentration greater than the critical pigment-binder ratio, and the ink comprises a solvent (typically water) soluble dye.
In another embodiment, the invention is a multi-layer, planar ingress tamper- and solvent-indicating label comprising a tamper-indicating label, a composition porous to solvent and coated over the label, and a crosslinked polymer film (through which solvent can migrate) coated or laminated to the composition. If the solvent-indicating label is a water-indicating label, the crosslinked polymer is hydrophilic. The tamper-indicating label can be of any construction, the composition comprises an organic solvent-soluble binder and pigment at a concentration greater than the critical pigment-binder ratio and dispersed solvent (typically water) soluble dye particles, and the crosslinked polymer film can absorb and transmit solvent while still maintaining integrity as a continuous layer. For water-indicating labels, one film that can serve these functions is polyvinyl(alcohol) crosslinked with aziridine.
In another embodiment, the invention is a multi-layer, planar ingress tamper- and solvent-indicating label comprising (A) a tamper-indicating label, (B) a composition coated over the label to form a first layer that is non-porous to solvent, (C) a second layer coated over the first layer and comprising an organic solvent-soluble binder, dispersed solvent (typically water) soluble dye particles, and (D) a crosslinked polymer film coated over the second layer that can absorb and transmit solvent while still maintaining integrity as a continuous layer. In operation, solvent comes in contact with the dye particles in the second layer, and dissolves the dye particles. The soluble dye then is trapped in or below the crosslinked polymer film staining it to produce a permanent color.
“Tamper-indicating label”, “tamper-evident label” and like terms mean a label that provides evidence that the label was removed, or an attempt was made to remove the label, from the substrate to which it was attached. The evidence is usually visible to the unaided human eye, and the evidence can be on the substrate, label or both.
“Solvent-indicating label”, “solvent-evident label” and like terms mean a label that provides evidence that it was in contact with a solvent. The evidence is usually visible to the unaided human eye, and the evidence is typically confined to the label itself.
“Tamper- and solvent-indicating label” and like terms mean that a label provides evidence that it was removed, or an attempt was made to remove it, from a substrate, and that it provides evidence that it was in contact with a solvent.
“Planar ingress label”, “planar ingress, multi-layer tamper- and solvent-indicating label” and like terms mean a label into which solvent enters primarily, if not exclusively, through a planar for facial or top) surface. Planar, or facial or top ingress is used in distinction to edge ingress in which solvent enters the label primarily, if not exclusively, through an edge surface.
“Solvent-soluble” and like terms mean that a material, e.g., dye, ink, etc., will at least partially dissolve, i.e., enter solution, in a solvent (e.g., water, or an organic compound, or a mixture of water and an organic compound such as water and an alcohol).
“Solvent” and like terms mean a substance that is capable of dissolving another substance (i.e., a solute) to form an essentially uniformly dispersed mixture (i.e., solution) at the molecular or ionic size level. Solvents include water and organic compounds. In the context of this invention, the solvents are typically liquid but can be a gas, e.g, steam.
“Organic solvent” and like terms mean a solvent other than water, e.g., a hydrocarbon or oxygenated or halogenated hydrocarbon such as gasoline, turpentine, chloroform, perchloroethylene, acetone, alcohol and the like.
“Dye” and like terms mean a visible light absorbing compound that is present in a molecularly dispersed (dissolved) form.
“Ink” and like terms mean a coatable or printable formulation containing a dye and/or pigment.
“Pigment” and like terms mean a visible light absorbing material or compound that is present in a non-molecularly dispersed (particulate) form.
“Binder” and like terms mean a film- or matrix-forming material in which dye or pigment particles are dispersed. Usually these materials are solvent polymers that exhibit adhesive properties towards fillers, dyes, pigments and the like. Representative of these materials are drying or mineral oils, and polymeric substances such as alkyd resins, acrylates and methacrylates, polyvinyl alcohol, ethyl vinyl acetate, etc.
“Planar surface”, “facial surface”, “top surface”, “bottom surface” and the like are used in distinction to “edge surface”. If rectangular in shape or configuration, a label will comprise two opposing planar surfaces joined by four edge surfaces (two opposing pairs of edge surfaces, each pair intersecting the other pair at right angles). If circular in configuration, then the label will comprise two opposing planar surfaces joined by one continuous edge surface. The labels can be of any size and shape and as such, so can the planar and edge surfaces, e.g., thin or thick, polygonal or circular, flat or wavy, etc.
The invention is described generally with reference to the drawings for the purpose of illustrating the certain embodiments only, and not for the purpose of limiting the scope of the invention. In the drawings like numerals are used to designate like parts throughout the same.
The embodiments described by the drawings are in the context of tamper- and water-indicating labels. Each of these embodiments can be altered to be tamper- and organic solvent-indicating labels by replacing the water-soluble components with organic solvent-soluble components, and the organic solvent-soluble components with water-soluble components. Those components that are impervious to water, e.g., the top film layer, the pressure sensitive adhesive, etc., are replaced with components that are either impervious to organic solvents or impervious to both water and organic solvents.
Composition 21 comprises (i) a solvent-based (i.e., non-aqueous based) binder, (ii) a non-water soluble pigment that is present at a concentration above the critical pigment to binder ratio, and (iii) dispersed water-soluble dye or pigment particles. The critical pigment to binder ratio is that ratio at which there is just enough volume of binder to fill all of the space between pigment particles such that any additional pigment results in void formation. The presence of this excess non-water soluble pigment in the composition renders the composition porous to liquid water. Typically, the excess non-water soluble pigment is present in the composition on a volume percent (vol %) basis, based on the volume of the binder, of at least 50, preferably at least 65 and more preferably at least 75, vol %. The water-soluble dye or pigment particles are present at a fairly low concentration, e.g., typically at a wt % between 1 and 20, preferably between 2 and 10 and more preferably between 4 and 8, based on the weight of the composition. One or more dyeing assistants, e.g., sodium chloride or sodium sulfate, can also be used if desired.
The color of the dye and pigment can vary to convenience and depending upon the amount and color of the pigment, the dye can be hidden to some extent until wetted. Pigments can include but are not limited to silicas, aluminas, carbonates, clays, metals, metal oxides, glasses, and solid forms of dyes, polymers and any insoluble particulates. The porous composition is sufficiently porous that water can quickly enter, yet sufficiently thin that the underlying tamper-indicating features remain operational.
The water-soluble dye or pigment is present in dispersed or particulate form. The pigment or particles are typically smaller than 100, preferably less than 50, microns to minimize visibility. Upon contact with water, the particles dissolve and the dye “blooms” thus becoming highly visible. If the dye in particulate form is too intense such that its color is objectionable, this can be moderated by adding a complementary colorant such that the color of the dye is muted or “greyed-out” until activated upon contact with water. For example, a colorant selected to give a red color upon contact with water may impart a pink color to composition 21. If a pale green colorant, e.g., dye, pigment, ink, is included in composition 21, then the observed color is of a more neutral hue.
Although the invention has been described in considerable detail by the preceding examples and reference to the drawings, this detail is for the purpose of illustration and is not to be construed as a limitation upon the spirit and scope of the invention as it is described in the appended claims. All U.S. patents, allowed U.S. patent applications and U.S. Patent Application Publications cited above are incorporated herein by reference.
This application claims the benefit of U.S. provisional application Nos. 60/870,271 and 60/885,710 filed Dec. 15, 2006 and Jan. 19, 2007, respectively.
| Number | Date | Country | |
|---|---|---|---|
| 60870271 | Dec 2006 | US | |
| 60885710 | Jan 2007 | US |
