MXPA00010404A - Tamper-indicating article for reusable substrates - Google Patents

Abstract

A tamper-indicating article comprises (a) a pressure-sensitive adhesive film or pressure-sensitive adhesive-coated tape that can be removed, without exhibiting cohesive failure, from a substrate surface (e.g., an automobile windshield) by stretching the film or tape;and (b) at least one damageable layer that shows cohesive or intralayer failure when an attempt is made to remove the article from the substrate surface. The article is especially useful for application to valuable, non-disposable substrates and can be removed therefrom without substrate damage.

Description

INDICATOR ARTICLE OF THE UNDUE USE FOR REOTILIZABLE SUBSTRATES Field of the Invention This invention relates to articles indicating improper use, coated with adhesive, sensitive to pressure.

Background of the Invention A variety of articles coated with a pressure adhesive, for example, labels or gummed labels, have been developed to provide visual evidence of misuse. In general, the articles have been designed to leave a residual indication, adhering tenaciously, of improper use on the surfaces of the substrate. Such articles and / or their residues can be removed only with the aid of solvents and / or mechanical scraping, which can damage the surfaces of the substrate. Accordingly, for valuable substrates (i.e., reusable, non-disposable substrates, such as automobile windshields), there is an R? F.124366 need in the art for an article that exhibits permanent evidence of misuse when any inmate is removed from the substrate, but this either leaves no residue during the removal or provides a residue that is removable without the aid of the solvents or mechanical scraping. Such an article must exhibit sufficiently high adhesion to the substrate to enable it to remain adhered during normal use conditions and must provide a sufficient indication of misuse to render it non-transferable (eg to another vehicle).

Brief Description of the Invention Briefly, in one aspect, this invention provides an article indicating misuse for use on valuable, ie, non-disposable or reusable substrates. The article comprises (a) a pressure sensitive adhesive film or tape covered by a pressure sensitive adhesive that can be removed, without exhibiting a cohesive failure, from a surface of the substrate (eg, a car windshield) by the stretching of the film or tape; and (b) at least one layer that can be damaged showing a cohesive or crosstraining failure when an attempt is made to remove the article from the surface of the substrate. Preferably, the component (b) comprises signals or indications and / or a holographic layer, and the component (a) comprises a film of pressure sensitive adhesive or a tape coated with a pressure sensitive adhesive that can be removed by stretching at an angle of approximately 45 degrees with respect to the surface of the substrate. The article also preferably comprises additionally a retroreflective layer. The indicative characteristics of the misuse of the article of the invention are derived from the incorporation of a layer that can be damaged, for example, a layer that can be destroyed (totally or in part) or that is irreversibly deformable. The cohesive strength of this layer (component (b)) is less than the strength of the adhesive between (a) and the substrate, and this adhesive strength is less than the cohesive strength of component (a). The article thus remains durably attached to a surface of the substrate under the conditions of normal use. However, an attempt to forcefully remove the article from the substrate leads to the cohesive or intra-layer failure of component (b), accompanied by the separation of components (a) and (b). The component (a) remains substantially intact and bonded to the surface of the substrate. The article provides both a sufficient indication of the misuse making it non-transferable to another substrate. Although the article of indication of the misuse of the invention can be used on a wide variety of substrates, it is especially useful for application to substrates which are not disposable, single-use substrates, for which use is desirable. repeated or continuous. An attempt to remove the article from a substrate will activate its indicator characteristics of misuse, still the portion of the remaining article on the substrate (after activation) can be easily and completely removed without the need for chemical agents (eg, organic solvents) or mechanical tools (eg, blades or scrapers). Therefore, the problem of the prior art of substrate damage is avoided. Accordingly, this article is particularly useful as a safety label for a vehicle window, bumper or fender, license plate; as a closing seal for portfolios, boot circuits for computer disk, doors, and filing cabinets; and as a security label for identification cards and other documents.

In another aspect, this invention also provides a substrate that carries the indicator article of the misuse of the invention.

Brief Description of the Drawings These and other features, aspects, and advantages of the present invention will become better understood with respect to the following description, the appended claims, and the accompanying drawings, wherein: Figures 1 and 2 show sectional views of the two modalities of the indicator article of the improper use of the invention. Figure 3 shows a sectional view of the embodiment of Figure 2 after application to a substrate and the subsequent activation of the characteristics indicative of the misuse of the modality during the attempted removal of the substrate. These Figures, which are idealized, are not shown to scale and are proposed to be illustrative only and not limiting.

Detailed description of the invention Reference Numbers: Indicator of misuse 20, 40 Adhesive (s) sensitive to pressure 30 Carrier 50, 55 Layers that can be damaged 60 Defined release coating 70 Primer or Preparator 80 Retroreflective layer 90 Substrate Component (a): Film or Adhesive Tape Pressure Sensitive The component (a) of the indicator article of the misuse of the invention can be better understood by reference to the accompanying drawings, wherein Figures 1 and 2 show the embodiments of the article 10 of the invention wherein a doubly coated tape it works as the component (a) of the article. The doubly coated tape comprises a carrier 30 carrying a pressure sensitive adhesive 20 on at least a portion of a first major surface thereof and a pressure sensitive adhesive 40 on at least a portion of a second major surface thereof. The pressure sensitive adhesives (PSAs) 20 and 40 may be the same or different in composition, depending on the nature of the substrates and component (b). The PSAs are, for at least some embodiments, preferably chosen to provide a bond to the substrate which is of a greater adhesive strength than the bond between the components (a) and (b). Alternatively, a PSA film (or even a PSA tape with a single cover having a carrier that is capable of adhering to component (b)), may be used in place of a double-coated tape as component (a) , provided that the film (or the single-deck tape) can be designed to provide the appropriate adhesive strengths for a particular application. PSA-coated tapes and PSA films suitable for use in the preparation of the article of the invention are those which can be removed, without exhibiting a cohesive failure, from a substrate surface by stretching. Useful PSAs include those acrylic PSAs, block copolymer PSAs, PSAs from rubber resins, poly (alpha olefin) PSAs, and silicone PSAs that exhibit sufficient adhesion to a substrate selected for provide a bond that is durable under conditions of normal use and of sufficient stretch capacity and cohesive strength (alone and / or in combination with a carrier that will be cleanly removable from the substrate by stretching). Acrylic PSAs and silicone PSAs are generally preferred because of their light transmission capacity characteristics (more preferably, transparency), with the acrylic PSAs being more preferred. Optionally, the PSA layer (s) may contain one or more additives such as tackifying resins, plasticizers, antioxidants, fillers, and other common additives, depending on the particular application.

Suitable carriers for PSA include both elastic and inelastic polymeric films (preferably, lightweight films); more preferably, transparent films) exhibiting sufficient stretch capacity (a suitable Young's modulus to be manually stretchable) and a tensile strength to enable the strip to be removed from a surface of the substrate by stretching the the tape manually and without breaking the carrier during the removal. Representative examples of suitable polymer films include polyolefins, for example, polyethylene, polypropylene, and polybutylene; vinyl polymer, for example, poly (vinyl chloride) and poly (vinyl acetate); acrylic polymers; silicone polymers; natural or synthetic rubbers; polyurethanes; and mixtures thereof. Copolymers, for example, ethylene / methacrylate, ethylene / vinyl acetate, acrylonitrile / butadiene / styrene, ethylene / propylene, and block copolymers (for example, styrene-isoprene-styrene (SIS) or styrene-ethylene-butylene- Styrene (SEBS)) can also be used. Polyolefins, especially polyethylene and polypropylene, and block copolymers are preferred, with linear low density polyethylene, low density polyethylene, and block copolymers of SIS and SEBS which are more preferred. Low density, linear polyethylene is the most preferred. If desired, the carrier can be treated or its composition modified to improve its adhesion to the PSA (s). For example, the carrier can be treated with electronic beam or arc in corona, or coated with a composition that promotes adhesion, or, alternatively, the carrier can contain added chemical groups or adhesion promoter compounds. The carrier may also contain other types of additives, for example, fillers, tackifiers, or plasticizers.

The PSA coated tapes and the preferred PSA films for use as the component (a) are those which can be removed cleanly from a substrate by stretching in a direction substantially parallel to the surface of the substrate. Such tapes and films are described, for example, in DE 3,331,016 (Beiersdorf AG), U.S. Pat. No. 4,024,312 (Korpman), and U.S. Pat. No. 5,516,581 (Kreckel et al.). DE 3,331,016 discloses an adhesive film comprising a PSA of sticky block copolymer and exhibiting high elasticity, low plasticity, greater cohesion than adhesion, a decreasing adhesive strength during stretching, and a ratio of the removal force with respect to the breaking force of 1: 2 or larger. The U.S. Patent No. 4,024,312 discloses a tape comprising a PSA of rubber resin or a PSA of sticky block copolymer and a carrier of the elastic and highly extensible block copolymer exhibiting a longitudinal elongation at break of at least about 200 percent and a 50 percent rubber modulus of no more than about 13.8 N / mm2 (2,000 pounds per square inch). A preferred tape especially for use as component (a) is the removable adhesive tape described in U.S. Pat. No. 5,516,581. This tape it comprises a highly extensible and substantially inelastic carrier and a PSA layer. The carrier has a tensile strength at break that is sufficiently high so that the carrier does not break during the removal of the tape from a surface of the substrate (eg, a tensile strength at break preferably of at least about 29.6 N / mm2 (4300 pounds per square inch (psi)), more preferably at least about 36.5 N / mm2 (5300 psi), even more preferably at least about 43.4 N / mm2 (6300 psi). has a longitudinal elongation at the break from about 50 to about 1200 percent (preferably from about 150 to about 700 percent, more preferably from about 350 to about 700 percent), with less than about 50 percent of elastic recovery after the stretching (preferably less than about 30 percent, more preferably, less than approximately 20 percent), and a Young's modulus of at least about 17.2 N / mm2 (2500 psi) (preferably at least about 20.7 N / mm2 (3000 psi)) but less than about 500 N / mm2 (72,500 psi) (preferably, less than about 345 N / mm2 (50,000 psi), more preferably, between about 34.5 and about 207 N / mm2 (5000 and 30,000 psi)). The PSA is preferably highly extensible, does not separate from the carrier during stretching, and has a higher cohesion than adhesion to any suitable substrate. After it is applied to a substrate, the adhesive tape becomes firmly bonded, but can be easily removed without damaging the substrate by simply stretching it, preferably at an angle of approximately 45 degrees to the surface of the substrate, more preferably in one direction substantially parallel, for example less than about 35 degrees (preferably, less than about 30 degrees, more preferably, less than about 10 degrees), with respect to the surface of the substrate.

Component (b): Layer (s) that can be damaged The component (b) of the article of indication of misuse of the invention can be better understood by reference to the accompanying drawings, wherein Figures 1 and 2 show the embodiments of the article 10 of the invention wherein (b) ), which comprises at least one layer that can be damaged, is attached to the component (a) through contact with the adhesive sensitive to the pressure 40. In the embodiment of Figure 1, the damaging layer 50 (a paper layer, optionally carrying a configured release liner) serves as the component (b). Figure 2 shows a preferred embodiment of the article 10 of the invention wherein the damageable layers 50 (ink comprising marks or signals) and 55 (a holographic film) together constitute the component (b). In general, the damaged layer has a limited cohesive strength and is the weakest layer in the multi-layer article. This is thus the predetermined point of failure of the article during the attempted removal of the article from a substrate. The damaging layer may comprise a brittle material that breaks during misuse (eg, a metallized or non-metallized holographic film such as those described in EP 253,089 (LGZ Landis &Gyr Zug AG), EP 328,086 (American) Bank Note Holographics, Inc.), EP 401,466 (Landis &Gyr Betriebs AG), and US Patent No. 4,856,857 (Takeuchi et al.), Or an acrylic resin optionally containing ceramic microspheres); a paper (for example, as shown in Figure 1), wherein the internal strength and the thickness of the paper are chosen so that the paper layer exhibits an intralayer flaw during the removal of the article; the marks or signals (for example, comprising an ink, as in Figure 2) applied to an inner layer by any of a variety of methods including, for example, transfer processes and direct printing processes such as thermal transfer printing, printing by ink jet, laser beam printing, flexographic printing, gravure printing, and screen printing; and any other types of layers that are capable of being destroyed (totally or partially) or irreversibly deformed during the removal of the intended article. Such layers may comprise, for example, a hot melt adhesive, a pressure sensitive adhesive, and / or an irreversibly deformable polymer film. Preferred, damaging layers are light transmitters (more preferably, transparent). Preferably, the article of the invention includes (as a layer that can be damaged) a holographic film, for example, one which comprises a structured sublayer and an optional reflecting sublayer. The structured sublayer may be formed by several methods that are well known in the art, for example, as described in U.S. Pat. No. 4,856,857 (Takeuchi et al.). It can be made from materials such as polymethyl methacrylate (PMMA), nitrocellulose, and polystyrene. The structured sublayer may include a microstructured relief configuration of holographic or diffraction imagery in the form of logos or configurations that reflect light. In one embodiment, a microstructured, embossed sublayer can be formed by contacting the material from which the structured sublayer will be made with a non-deformable embossed plate having a microstructured relief configuration, and applying heat and pressure. Alternatively, the structured sublayer can be made by any other suitable process such as radiation curing, and can be made of materials such as urethane, epoxy, polyester and acrylic monomers and oligomers, which are formulated with photoinitiators, cast or cast on a non-deformable tool having a microstructured relief configuration, and cured with radiation. An optional reflection sublayer can be coated on the structured sublayer either before or after embossing. The reflecting sublayer preferably has a higher refractive index than the structured sublayer. In a preferred embodiment, the reflecting sublayer is substantially transparent and colorless. Illustrative examples of the materials of the reflecting sublayer include but are not limited to trioxide bismuth, zinc sulfide, titanium dioxide, and zirconium oxide, which are described in U.S. Pat. No. 4,856,857 (Takeuchi et al.). Less transparent materials such as thin aluminum or silver or configured reflectors can also be used. The reflecting sublayer improves the reflection of light through the structured sublayer due to the difference in the Fraction Index between the structured and reflective sublayers. Accordingly, the structured holographic configuration is more easily visible to the naked eye once the reflective sublayer is coated on the structured sublayer, and, if desired, a preparation adhesive that promotes adhesion, can be applied directly to the structured sublayer without diminishing the visibility of the structured configuration. The article of the invention may comprise more than one layer that can be damaged, as shown in Figure 2 wherein both the markings or signals and a holographic film are used and wherein the pressure sensitive adhesive 40 can also serve as a layer that can be damaged if it is selected to have a low cohesive resistance. The failure configuration of multi-layer articles such as the article of the invention is complex and depends on several parameters, such as the elasticity or brittleness of the various layers, the tensile strength of the materials used, the adhesion between the adjacent layers, the thickness of the layers and the configuration of any discontinuous layers, as well as during the removal, the direction, angle, force, and speed and temperature during removal. Therefore, in some cases, the removal of the article from a substrate can lead to failure at points other than, or in addition to, the pre-selected (s) damaged, pre-selected layer (s) of the article. . However, in general the damaging layer (s) of the article fail or break and through this a permanent indication of misuse is provided. This fault can be better understood by the reference to Figure 3, which shows a sectional view of the preferred embodiment of Figure 2 after application to a substrate 90 and the subsequent activation of the indication characteristics of the misuse of the article during the attempted removal of the substrate.

Additional component In addition to the damageable layers 50 (marks or signals) and 55 (holographic film), the embodiment of Figures 2 and 3 (a preferred embodiment) further comprises a configured release liner., a primer coating 70, and a retroreflective layer 80. The configured release coating 60 (which can be any of the types known in the art, for example, of compositions based on silicone, fluorinated chemicals, waxes, and polyvinyl alcohol, and can be made in any of the known configurations) and the primer coating 70 (which can also be selected from the known primer coatings and treatments, for example, of the types described above for use on the carrier) serves to provide larger or smaller adhesion areas of the holographic film 55 (which carries the markings or signals 50) to the underlying retroreflective layer 80. Accordingly, during the attempted removal of the article from a substrate, the holographic film bearing the marks or signals is broken, with the portions of the film and the marks or signals remaining with the component (a) (attached to the sensitive adhesive). the pressure 40) and the portions remaining attached to the retroreflective layer 80. The relative sizes and spacings of the portions remaining with the component (a) and with the retroreflective layer, respectively, may be varied according to the variable nature of the configuration (of the coating). configured release) and the extent of surface coverage, as is known in the art.

As shown in Figures 2 and 3, preferred embodiments of the article of the invention comprise a retroreflective layer 80, which preferably comprises the icroparticles of the corner elements of cubic shape. For example, the retroreflective layer, as described in U.S. Pat. No. 2,407,680 (Palmquist et al.), May comprise a monolayer enclosed by glass microspheres that are coated in a spacer resin comprising, for example, polyvinyl butyral or polyester. The spacer resin adapts to the shape of the microspheres. A reflective sublayer extends below the spacer resin, and may comprise opaque materials such as silver, aluminum, chromium, nickel, or magnesium, or reflective materials of high transparency index such as zinc sulphide, or the multi-layer reflectors as described in US Pat. No. 3,700,305 (Bingham). Therefore, the Light that is introduced to the retroreflective layer is focused by the glass microspheres through the spacer resin and reflected by the reflecting sublayer back through the spacer resin and the glass microspheres towards an observer. The retroreflective layer may further comprise a backing sublayer, which may optionally carry a heat-activatable or pressure sensitive adhesive to assist adhesion to the reflecting sublayer. A sublayer of union by means of pearls, optional, can also be provided. In such an embodiment, the glass microspheres can be coated on the bonding sublayer by means of beads, and then the spacer resin can be coated onto the glass microspheres. The sublayer of union by means of beads can contain a colored pigment (which includes the black pigment) which gives the retroreflective layer a colored appearance in normal light, and the appearance of a different color, such as silver, in light retroreflected. This is further described in U.S. Pat. No. 2,407,680 (Palmquist et al.). The reverse side of the microspheres can be protected by any suitable sealing or protective material). An alternative retroreflective layer 80 comprises a multiplicity of retroreflective elements of cubic corners instead of glass microspheres and resin. Cubic corner elements can be made of materials such as vinyl, polycarbonate, or acrylic for embossed cubic corner elements, and of urethane, epoxy, polyester, and acrylic monomers and oligomers for cubic corner elements cured with radiation. The cube corner elements typically have three mutually perpendicular faces with surface areas of approximately 1.9 x 10 ~ 3 to 0.1 mm. The retroreflective elements of cubic corners can be embossed by a master mold in a material in the form of sheets or sheets under the appropriate temperature and pressure. The elements can also be created by coating a radiation curable resin on a master mold, laminating a superposed film under sufficient pressure, and solidifying the resin by radiation curing. The retroreflective elements of cubic corners can optionally have a reflective coating, which can be made of the same materials as those previously described for the retroreflective microsphere material and is typically applied on the back surface of the cubic corners. A sealant film or adhesive layer can be applied over the reflective coating while still being allowed retroreflection. Also, retroreflective elements of cubic corners can be used without a reflective coating. A holographic film and a retroreflective layer can be joined together by an adhesion layer. Suitable materials for such an adhesion layer include the primers (e.g., the preparation coating 70 in Figures 2 and 3) or the adhesives, either as coatings or as films, such as urethanes, olefins, vinyls, and materials acrylics The adhesion layer can be of any suitable thickness and can be applied either to the holographic film or to the retroreflective layer or to both prior to the bonding of these layers together. The adhesion layer can be made from a material that can be shrunk with heating, which provides protection against improper use by the application of heat, because the application of a sufficient amount of heat causes the layer that can be shrink with heat become deformed. The polyolefin film is a preferred material for the binding layer which can be shrunk with heat. An optional, configured coating layer (e.g., the release coating configured in FIGS. 2 and 3) that either increases or reduces the adhesion, can be provided at the interface of the holographic and retroreflective layers. A particularly useful application of the configured layer is one in which this layer is used adjacent to a layer having imprinted markings or signals or an array of the one or more holographic emblems (e.g., holographic film 55 in Figures 2 and 3) . When the article is delaminated in the configured coating layer, a portion of the mark (s) or emblem (s) remains attached to each delaminated portion. An optional marking or signal configuration can be applied in the same places as the configured coating layer described above, or in other places within the construction. The configuration of marks or signs or logos are preferably printed with colored inks, inks with the effect of the color of the beads, or the inks visible under ultraviolet light, or their images are formed using organic pigments or dyes in a configuration. These colored markings or signals are especially useful when printed at some location above the front surface of a retroreflective layer having a colored bead bond. In normal light, the line of colored beads (preferably black) hides the colored marks or signals and only the hologram is visible typically, because the hologram decreases the visibility of colored marks or signals. However, under retroreflective lighting conditions, the colored markings or signals are brightly visible against the background, which is preferably silver, and the hologram is no longer visible. The image of the wide or narrow angular marks or signals in the retroreflective layer of microspheres can also be formed, for example, by the laser beam imaging process described in U.S. Pat. Nos. 4,688,894 (Hockert) and 4,200,875 (Galanos). Usually, when this process is used to image the retroreflective materials of microspheres enclosed with opaque reflectors, the marks or signals are visible with both normal and retroreflective illumination. This invention also includes the use of the retroreflective material of microspheres enclosed with transparent reflectors, with which the marks or signals are not visible in normal light but are visible only under retroreflection. Therefore the marks or signals are hidden until they are observed under retroreflective lighting conditions. When, for example, an article for application to the inner part of a windshield of the motor vehicle is desired, the components used in addition to components (a) and (b) are preferably light transmitters (more preferably, transparent), especially when used with a posterior retroreflective layer or a subsequent layer bearing marks or signals which must remain visible from the outside of the vehicle . When one or more heat-sensitive components, eg, thermoplastics, are used in such an article, the component (s) are preferably used in combination with both a configured release coating and a continuous coating of the primer to promote accession. The article indicating the misuse of the invention, if desired, may further comprise at least one coating (e.g., to protect the PSA layer 20). Such a coating may be of materials known in the art, such as paper or a polymeric film (optionally bearing a release coating or having been treated or processed in some way to make it possible, for example, to release the PSA from the coating). The article of the invention can be prepared using conventional coating, lamination, and / or transfer techniques. The thicknesses of the various component layers can vary widely, depending on the number and nature of the particular components, the particular application, and the desired performance characteristics. The objects and advantages of this invention are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and des, should not be construed to unduly limit this invention.

Examples Test Methods Adhesion Test During 180 ° Detachment Adhesion during peeling is the force required to remove a flexible sheet material, coated with an adhesive, from a test panel. The adhesion during detachment is measured at a specific angle and speed of removal. In the following examples, this adhesion force during peeling is expressed in Newtons / centimeter of width (N / cm) of the coated sheet. The adhesion forces during the detachment measured everywhere are the adhesion forces during the detachment initials taken at approximately one minute of the drying time, unless otherwise indicated. These initial adhesion forces during the release can not be indicative of the aging adhesion forces during the release which can be obed. Adhesion during detachment (180 °) are measured according to PSTC-1 (Test Methods of the Pressure-Sensitive Tape Council, 9th Edition, 1989, Deerfield, II., USA). A strip (1.27 cm wide) of the sheet coated with the adhesive was applied to the horizontal surface of a clean sless steel test plate with at least 12.7 linear centimeters of both surfaces that are in firm contact. One pass with a 2 kg hard rubber roller was used to apply the strip. The free end of the coated strip was folded over itself until it almost touched so that the angle of removal was 180 °. The free end was set to the scale of the adhesion tester. The sless steel test plate was clamped in the jaws of a stress test machine that was able to move the plate away from the scale at a constant speed of 30.5 cm / min. The reading of the scale was recorded in Newtons when the tape was detached from the glass surface. The data were reported as the average of the range of numbers observed during the test.

Adhesion during Detachment from the Glass to Various Clearance Angles Adhesion values during detachment were measured as described above with the exception that the equipment configuration was altered to allow the forces of removal to be measured at other detachment angles. A glass test plate was anchored or fixed in the lower jaw of the tension testing machine in various configurations so that when the end of the coated strip was pulled by the second opposite jaw of the machine, the strip was removed from the plate at other angles, in addition to the 90 ° and 180 ° detachment angles that are more commonly tested. The force required to separate the adhesive coated strip from the plate was recorded, as well as the elongation during the strip removal process. The removal angles of 0 °, 45 °, 90 °, 145 °, and 180 ° were evaluated.

Example 1 A sheet of photocopying paper measuring 5 cm x 7 cm was gravure coated on one side with a checkerboard configuration of a composition of release comprising an organopolysiloxane-polyurea copolymer. The organopolysiloxane-polyurea copolymer was the product of the condensation reaction of an organopolysiloxane diamine with a diisocyanate and a diamine chain extender and was prepared essentially as described in U.S. Pat. Nos. 5,214,119 and 5,290,615. The organopolysiloxane-polyurea was coated from a solution of isopropanol in such a way that the unique elements of the resulting checker board configuration measured 5 mm on each side. The paper coated with the configuration was dried at 70 ° C for 1 minute. A sheet or sheet of a linear, low density polyethylene (LLDPE) film treated with a crown arc, 38 microns (1.5 mils) thick, available as XMAX 312.0 LLDPE from Huntsman Packaging, Scunthorpe, UK, is coated on both sides with a pressure sensitive adhesive, and then cut to the same dimension as the paper described above (5 cm x 7 cm). The adhesive on one side of the film was an acrylic solvent-based pressure sensitive adhesive comprising a terpolymer of 70% by weight of isooctyl acrylate, 22.5% by weight of methyl acrylate, and 7.5% by weight. in weight of acrylic acid. The adhesive had an inherent viscosity of 0.7 and contained an agent of crosslinking of thermally activated bisamide. (Adhesion during detachment of this adhesive on a polyethylene terephthalate (PET) film of 50 microns (2 mils) was evaluated, and an adhesion value during peeling at 180 ° of 5.6 N / cm was obtained ). The adhesive was coated on the LLDPE film using a knife coater and dried in a pressurized air oven to give a final adhesive coating weight of 40 g / m2. A 50 mil (2 mil) thick silicone-treated polyester coating was then laminated to the dry adhesive layer. The reverse side of the LLDPE film was coated with an organic solution of an acrylic pressure sensitive adhesive. The adhesive solution was prepared by combining two adhesive compositions in a weight ratio of 11.9 parts of Adhesive Composition A (30 parts of the solid components thereof) and 88.1 parts of Adhesive Composition B (70 parts of the solid components). Of the same) . (This adhesive solution was also coated on a 50 mil (2 mil) thick polyethylene terephthalate film using a knife coater to give a final coating weight after drying in a forced air pressure oven. g / m2, and an adhesion value during the 180 ° detachment of 1.4 N / cm was obtained). Adhesive Composition A comprised an acrylic pressure sensitive adhesive, having a weight ratio of isooctyl acrylate: acrylic acid of 95.5: 4.5, which was prepared essentially by the emulsion polymerization method described in Example 5 of the US Patent No. Re. 24,906 (Ulrich). Following the polymerization, the resultant acrylic pressure sensitive adhesive was coated from the emulsion and dissolved in a 80/20 mixture of heptane and propyl alcohol to form a 25% by weight solution. The Adhesive Composition B comprised an acrylate microsphere adhesive, which was prepared essentially as described in U.S. Pat. No. 3,691,140 (Silver), using 98% isooctyl acrylate and 2% ammonium acrylate. The microspheres were isolated from the resulting suspensions and then dispersed in heptane to form a dispersion of 8 wt.% Microspheres. The surface coated with the paper configuration described above was then laminated to one side of the resulting doubly coated LLDPE film, which bears the adhesive containing the microspheres to form a simple embodiment of the use indicator article. undue of the invention. The polyester coating was removed from the article, and the resulting exposed adhesive layer was adhered to a tempered, shatterproof, or safety glass sheet of two layers and pressed firmly by hand. After 15 minutes, an attempt was made to remove the article from the glass substrate. The edge of the article was slightly raised and pulled in a direction of approximately 90 ° to the surface of the substrate. This caused the article to be divided into two separate parts. One part remained on the substrate, and the other part completely disconnected. The part that remains on the substrate comprised the first adhesive layer, the film, the second adhesive layer, and a checker board configuration of the areas comprising the fibers deslammed from the paper. The fibers of the paper were easily identifiable in the areas where no release coating was present. The part that was completely disengaged comprised the configured release liner and the rest of the paper. Visual inspection revealed that the paper has been discarded on one side in a checkerboard configuration. The remaining parts on the substrate were removed in one piece by holding it on its edge and pulling at an angle of approximately 45 degrees with respect to the surface of the substrate. The part stretched during the removal process but did not break. The pressure-sensitive adhesive bonded to the substrate broke progressively and cleanly and, after removal, no residue of the adhesive could be observed on the substrate. A number of doubly coated LLDPE films were prepared as described above and were applied to a glass test plate. Adhesion values during detachment obtained at various removal angles are shown in Table 1.

Table 1 * MD = film machine stretch removal CD = stretch removal in the cross direction of the film DD = stretch removal in the diagonal direction of the film Example 2 The non-retroreflective back side of a flexible retroreflective sheet comprising glass beads as reflective elements (available as the VP5500 Scotchlite® Reflective Sheet from 3M Company, St. Paul, MN) was hot rolled to a polyethylene terephthalate film (PET) white, opaque, 25 microns thick to protect its aluminum reflective layer. The sheet was then coated on its front retroreflective surface with a continuous adhesion layer of polyurethane resin (available as Neorez® R960 from Zeneca Resins, Waalwijk, The Netherlands). The water-based resin composition was applied by gravure coating and dried at 80 ° C for 1 minute at a dry thickness of about 4 microns. A checker board configuration of the release composition described in Example 1 was then applied on the resulting adhesion layer by the gravure coating, essentially as described in Example 1. Next, a continuous layer of ink based on a solvent, transparent (available as Transparent Ink 1900 Scothlite® (Blue-Violet) 3M Company, St. Paul, MN) was then applied over the release coating configured by stencil printing. The resulting ink coating was dried for 40 seconds at 60 ° C to give a dry thickness of about 10 microns. The doubly coated LLDPE film of Example 1 was adhered to the laminate comprising the reflective sheet, the adhesion layer, the configured release coating, and the ink layer. The side of the film carrying the adhesive containing the microspheres was attached to the ink layer using a mechanical laminator at 23 ° C to form an article indicating improper, retroreflective use. The protective PET film was removed from the article, and the resulting exposed adhesive layer was adhered to a two-layer tempered safety glass sheet and pressed down firmly by hand. After 15 minutes, an attempt was made to remove the article from the glass substrate. The edge of the article was lifted lightly and pulled in a direction of approximately 90 degrees with respect to the surface of the substrate. The article could not be removed in one piece. Instead, it exhibited an intralayer flaw and separated into two parts, one that remained attached to the substrate and the other disjoined completely. The part that remained attached to the substrate comprised the doubly coated LLDPE film and the easily identifiable portions of the ink layer corresponding to the areas bearing a release coating. The part that was completely dissociated from the substrate comprised the reflective sheet, the adhesion layer, the configured release coating, and the portions of the ink layer corresponding to the areas where the coating of the release was absent. The damaged ink layer thus provided a visual indication of misuse. The part of the article that remained attached to the glass substrate was then removed from the one-piece glass by holding the part at its edge and pulling at an angle of approximately 45 degrees with respect to the surface of the substrate. The part stretched during the removal process but did not break. The pressure-sensitive adhesive bonded to the glass substrate broke down Progressive and clean, and, after removal, no adhesive residue could be observed on the substrate.

Example 3 The sheet of Example 2 was coated on its front retroreflective surface with a continuous polyurethane adhesion layer and a configuration coating of the release composition, essentially as in Example 2. A thin transparent holographic film (available from Crown Roll Leaf, Peterson, NJ) was then laminated onto the configured release coating using a heated laminator (available from Sallmetal, Raalte, The Netherlands) at 100 ° C. The holographic film comprised a polyester release coating, a structured layer based on polymethyl methacrylate, a zinc sulfide reflector of high refractive index, and a thin adhesive layer. After the lamination, the polyester coating was removed. A continuous layer of solvent-based ink, transparent, (available as the Scotchlite® Transparent Ink 1900 (Blue-Violet) from 3M Company, St. Paul, MN) was then applied over the thin transparent holographic layer by stencil printing . The coating of The resulting ink was dried for 40 seconds at 60 ° C to give a dry coating thickness of about 10 microns. The doubly coated LLDPE film of Example 1 was then adhered to the laminate comprising the reflective sheet, the adhesion layer, the configured release coating, the holographic film, and the ink layer. The side of the film carrying the adhesive containing the microspheres was attached to the ink layer using a mechanical laminator at 23 ° C to form an article indicating misuse. The protective PET film was removed from the article, and the resulting exposed adhesive layer was adhered to a two-layer tempered safety glass sheet and pressed firmly by hand. After 15 minutes, an attempt was made to remove the article from the glass substrate. The edge of the article was raised slightly and pulled in a direction of approximately 90 degrees with respect to the surface of the substrate. The article could not be removed in one piece and was separated into two parts, one that remained attached to the glass substrate and the other that was completely disjointed. The part that remained attached to the glass substrate comprised the doubly coated LLDPE film and the easily identifiable portions in both the ink layer and the holographic film, these portions correspond to the areas where the release coating was present. The part that completely disengaged from the glass substrate comprised the reflecting sheet, the adhesion layer, the configured release coating, and portions of both the ink layer and the holographic film, these portions corresponding to the release coating were absent. The damaged ink layer thus provided a visual indication of misuse. The part that remained attached to the glass substrate was then removed from the one-piece glass by holding the part at its edge and pulled at an angle of approximately 45 degrees with respect to the surface of the substrate. The part stretched during the removal process but did not break. The pressure sensitive adhesive bonded to the glass substrate broke progressively and cleanly and, after removal, no adhesive residue could be observed on the substrate. A second indicator article of abuse was prepared essentially as described above in this Example 3 and adhered to a glass substrate and allowed to stand there for 40 days at 70 ° C to stimulate long-term exposure with respect to heating on a glass windshield. The tries Removal of the article led to intralayer failure and delamination as described above. The misuse was evident, because both the hologram and the ink layer were damaged during the removal process.

Example 4 Example 3 was repeated with the exception that the doubly coated LLDPE film carried the same acrylic-based pressure sensitive adhesive on both sides. The adhesive comprised a copolymer of isooctyl acrylate and acrylic acid in a weight ratio of 95.5 to 4.5. One hundred parts by weight of the copolymer were bonded with 25 parts by weight of a highly stabilized rosin ester resin (available as Foral® 85 from Hercules, Rijswijk, The Netherlands). Differential adhesion was provided using a higher coating weight of the adhesive on one side of the film than on the other. The coating on one side (the side to be used for fixing to a substrate) had a thickness of 100 microns. (Such an adhesive coating on a polyethylene terephthalate (PET) film of 50 microns (2 mils) thick exhibited an adhesion value during peeling. 180 ° of 7.5 N / cm). The adhesive coating on the opposite side of the film had a thickness of 50 microns. (Such an adhesive coating on a polyethylene terephthalate (PET) film 50 microns (2 mils) thick, exhibited an adhesion value during peeling at 180 ° of 4.0 N / cm). The resulting doubly coated LLDPE film was then adhered to the laminate of Example 3 comprising a retroreflective sheet, an adhesion layer, a shaped release coating, a holographic film, and an ink layer. The side of the film carrying the less thick adhesive coating was attached to the ink layer using a mechanical laminator at 23 ° C to form an indicator article of misuse. The article was adhered to a glass substrate, and the behavior of the article during the attempted removal of the substrate was similar to that described in Example 3. The part remaining on the substrate was removed by holding the part on its edge and pulling on a angle of approximately 90 ° with respect to the surface of the substrate. The part stretched but did not break during the removal process. After the adhesive bond to the substrate was completely broken, no adhesive residue was visible on the substrate.

A sheet of 220 microns thick of the styrene-ethylene-co-butylene-styrene block copolymer (SEBS), available from Shell Chemicals as Kraton® G-1657, was prepared by standard screw twin extrusion techniques. The resulting elastic sheet was coated on both sides with a pressure sensitive adhesive based on rubber resin comprising 100 parts by weight of the styrene-isoprene-styrene synthetic block polymer (available as Kraton® 1107 from Shell Chemicals), 129 parts by weight of an aliphatic sticky resin of C5 (available as Escorez® 1310 from Exxon, Belgium), 54 parts by weight of the polyterpene resin (available as Zonarez® A25 from Arizona Chemicals), and 3 parts of antioxidant (available as Irganox® 1076 from Ciba Geigy, Basel, Switzerland). The adhesive was coated on one side of the SEBS sheet to a thickness of 35 microns and the other side to a thickness of 19 microns. A polyester coating coated with silicone was laminated to the thicker adhesive coating. Adhesion during release of each adhesive coating to a stainless steel substrate was measured and found to be 6.8 N / cm (19 micron layer) and 8.5 N / cm (35 micron layer).

The doubly resulting coated sheet was laminated to form an improper use indicator article by bonding the coating of the thinnest adhesive of the sheet to the ink layer of a retroreflective laminate of the type described in Example 3. This laminated material comprised (in this order), the retroreflective sheet, a continuous bonding layer, a configured release coating, a thin, transparent holographic film, and a continuous layer of ink. The polyester coating was removed, and the article was pressed firmly against a clean glass plate. When removal from the substrate was attempted, the article delaminated essentially in the same manner as described in Example 3, leaving a part of the article on the substrate. The part of the article that remained attached to the substrate consisted of the doubly coated SEBS sheet and a checker board configuration of the hologram / ink fragments corresponding to the areas where the release coating was present. The part of the article that completely disengaged from the substrate comprised the retroreflective sheet, the adhesion layer, the configured release coating, and the portions of both the ink layer and the holographic film corresponding to the areas where no Release coating was present. The part of the article that remained attached to the substrate could be removed cleanly from the substrate by holding the part on an edge and stretching until it separated cleanly from the surface of the substrate.

Example 6 Example 5 was repeated with the exception that a different elastomeric sheet was used as a carrier for the adhesive layers. A sheet of 50 microns thick of the anisotropic, semitransparent elastic film, comprising 60 parts of the triblock polymer of styrene-isoprene-styrene (commercially available as Vector® 4111D from Deutsche Exxon Chemicals GmbH) and 40 parts of polypropylene (density of 0.9045 g / cm3, available as PPH 7060S from Fina Chemicals, Belgium) was prepared by an extrusion process. The resulting elastic sheet comprised the insoluble polypropylene fibers that extend in the plane of the sheet in the direction of the falling web, interspersed in an elastomeric matrix. The anisotropic sheet was extensible and elastic in the direction of the transverse web, but had less extensibility and elasticity in the direction of the downward web.

The elastic sheet was coated on both sides with the pressure sensitive adhesive based on the rubber resin of Example 5 and laminated to the retroreflective laminate used in Example 3, comprising the retroreflective sheet, a continuous adhesion layer, a configured release coating, a thin holographic film, and a continuous layer of ink. The thinner layer of the pressure sensitive adhesive on the elastic carrier was laminated to the ink layer of the retroreflective laminate. The article indicating the resulting misuse was affixed to a glass substrate. When attempts were made to remove the article from the substrate, the article delayed. The part of the article that remained attached to the substrate could be removed cleanly from the substrate by pulling the edge of a part and stretching it until the part separated from the surface of the substrate.

Example 7 An indicator article of abuse was prepared using a pressure sensitive adhesive (PSA) film (which does not comprise any carrier for the adhesive), instead of the doubly coated sheet or film comprising the carrier of the above Examples. The PSA film was an opaque film of the adhesive based on synthetic rubber resin (available as Power Strips® from Beiersdorf AG, Hamburg, Germany). The PSA film was homogeneous, and its two adhesive surfaces were covered with protective coatings. One of the coatings was removed from the film, and the exposed adhesive side was laminated to the retroreflective laminate of Example 3 (comprising (in this order) the retroreflective sheet, a continuous adhesion layer, a configured release coating, a film thin transparent holographic, and a continuous layer of transparent ink). The second protective coating was removed from the indicator article of the resulting misuse, and the article was adhered to a glass substrate. After 15 minutes, an attempt was made to remove the article. The article exhibited an intralayer failure and separated into two parts, one part completely disengaged and the other remaining attached to the surface of the substrate. The remaining part on the surface of the substrate comprised the PSA film, the entire ink layer, and a checker board configuration of the holographic film corresponding to the areas where the release coating was present. The configuration of the checkerboard of the film The damaged hologram could easily be observed when the light was reflected from the surface (of the completely disjointed part of the article) at certain angles. The part of the article that was separated, consisted of the retroreflective sheet, the continuous adhesion layer, the release coating configured in checkerboard form, and a checker board configuration of the holographic film corresponding to the areas where the release coating was absent. The part of the article that remains on the substrate could be removed from a part by pulling on a hold lug provided at one end of the PSA film at an angle of approximately 30 degrees with respect to the surface of the substrate.

Example 8 Example 3 was repeated with the exception that a doubly coated LLDPE film was prepared by coating both sides of the LLDPE film with the same acrylic-based pressure sensitive adhesive composition. The adhesive comprised a sticky copolymer of isooctyl acrylate and acrylic acid in a weight ratio of 95.5 to 4.5. One hundred parts by weight of the copolymer were bonded with 25 parts by weight of an ester resin of highly stabilized rosin (available as Foral® 85 from Hercules, Rijswijk, The Netherlands). Preferential adhesion was provided using a weight of the highest coating of the adhesive on one side of the film over the other. An indicator article of abuse was prepared by laminating the doubly resulting coated film to the retroreflective laminate of Example 3 (comprising the retroreflective sheet, a continuous adhesion layer, a shaped release coating, a thin transparent holographic film, and a continuous layer of transparent ink) by the bonding of the ink layer of the laminate material to the side of the doubly coated film bearing a lower coating weight of the adhesive. The resulting article was applied to a glass substrate, and, during the attempted removal, the article was delaminated. The remaining part fixed to the substrate comprised the doubly coated film and a configuration of the ink fragments and the holographic film. This part was removable by holding it and stretching it to break the adhesive bond to the surface of the substrate.

Example 9 Example 8 was repeated with the exception that the LLDPE carrier film was replaced with a low density polyethylene (LDPE) sheet having a thickness of 28 microns and a density of 0.92 g / cm 3 (available from Klerk's, Noordwijkhernout, Netherlands). The resulting article was applied to a glass substrate, and, during the attempted removal, the article was delaminated. The remaining part fixed to the substrate comprised the doubly coated film and a configuration of ink fragments and the holographic film. This part was renewable by holding it and stretching it to break the adhesive bond with the surface of the substrate.

Example 10 Example 3 was repeated with the exception that the flexible retroreflective sheet was replaced by a clear polyethylene terephthalate (PET) film 50 microns (2 mils) thick. The clear PET was provided with a continuous adhesion layer, a configured release coating, a thin holographic film, and a continuous ink layer, essentially as described in Example 3. The Indicator article of the resulting misuse was translucent when adhered to a glass substrate. During the attempted removal, the item was delayed. During the attempted removal, the item was delayed. The part that remains attached to the substrate was removable cleanly by stretching.

Example 11 Example 3 was repeated with the exception that the flexible retroreflective sheet of Example 3 comprising the glass beads as the reflective elements was replaced by a flexible retroreflective sheet comprising cube corner elements as reflective elements (available as Reflective Sheet 973 Flexible Diamond Grade® from 3M Company, St. Paul, MN). The resulting article was applied to a glass substrate, and, during the attempted removal, the article was delaminated. The part that remains fixed to the substrate comprised the doubly coated film and a configuration of fragments of the ink and the holographic film. This part was removable by holding it and stretching it until the adhesive bond broke to the surface of the substrate.

Various modifications and alterations of this invention will become apparent to those persons skilled in the art without departing from the scope and spirit of this invention.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, property is claimed as contained in the following

Claims (11)

1. An indicator article of misuse comprising: (a) a film of a pressure sensitive adhesive or a tape coated with a pressure sensitive adhesive that can be removed from a substrate surface, without exhibiting a cohesive failure, stretching the movie or the tape; and (b) at least one hardenable layer exhibiting a cohesive failure when an attempt is made to remove the article from the surface of the substrate, characterized in that the attempt to remove the article from the surface of the substrate also leads to separation. of the components (a) and (b), with the component (a) that remains attached to the surface of the substrate.

2. The article according to claim 1, characterized in that the film or tape can be removed from said surface of the substrate by stretching the film or tape at an angle of approximately 45 degrees to said surface of the substrate.

3. The article according to claim 1 or claim 7, characterized because the film of the tape comprises a pressure sensitive adhesive selected from the group consisting of acrylic pressure sensitive adhesives, block copolymers, rubber resin, poly (alpha olefin), and silicone, and where the tape comprises a carrier selected from the group consisting of the films of the silicone polymers, the films of the polyurethanes; polymer films comprising polymerized units derived from one or more olefin monomers, from one or more acrylic monomers, from one or more vinyl monomers, and from mixtures thereof; and the films of the mixtures or combinations of said polymers.

4. The article according to claim 3, characterized in that the pressure sensitive adhesive is selected from the group consisting of pressure sensitive adhesives, acrylics and silicone pressure sensitive adhesives; and wherein the polymers are selected from the group consisting of polyolefins and block copolymers.

5. The article according to claim 1, characterized in that the tape comprises: (a) a carrier having a longitudinal elongation in the break from about 50 to about 1200 percent, a Young's modulus of at least about 17.2 N / mm2 (2500 psi), but less than about 500 N / mm2 (72,500 psi), and a tensile strength at break which is sufficiently high so that the carrier does not break during the removal of the tape from the surface of the substrate; and (b) a pressure sensitive adhesive on at least a portion of at least a portion of at least one major surface of the carrier; the tape is capable of being firmly attached to the surface of the substrate and furthermore capable of being removed therefrom by being stretched at an angle of approximately 45 degrees to said surface of the substrate.

6. The article according to claim 1, characterized in that the damageable layer is selected from the group consisting of fragile materials, papers, markings or signs, hot melt adhesives, pressure sensitive adhesives, and polymeric films. irreversibly deformable.

7. An article indicating misuse, characterized in that it comprises: (a) a tape coated with the pressure sensitive adhesive comprising (i) a carrier having first and second major surfaces and having a longitudinal elongation at the break from about 50 to about 1200 percent, a Young's modulus of at least about 17.2 N / mm2 (2500 psi), but less than about 500 N / mm2 (72,500 psi), and a tensile strength at break that is sufficiently high so that the carrier does not break during the removal of the tape from a substrate surface, and (ii) a pressure sensitive adhesive on the substrate. at least a portion of the first and second major surfaces of said carrier; the tape is capable of being firmly attached to the surface of the substrate and furthermore capable of being removed therefrom by being stretched at an angle of approximately 45 degrees with respect to the surface of the substrate; (b) a hardenable layer exhibiting a cohesive failure when an attempt is made to remove the article from the surface of the substrate, the layer that can be damaged comprises marks or signs; (c) a configured release coating; and (d) a retroreflective layer.

8. The article according to Claim 1 or Claim 7, characterized in that the pressure sensitive adhe comprises the acrylic pressure sensitive adhe.

9. The article according to claim 1 or claim 7, characterized in that it also comprises a second layer that can be damaged, the second layer that can be damaged comprises a holographic film.

10. The article according to claim 9, characterized in that it also comprises a preparation coating.

11. A substrate, characterized in that it carries the article in accordance with claim 1 or claim 7.