초록 ▼

A tape or label for sealing a container that provides visual evidence if the seal is forced open or cooled below a breakdown temperature. The tape includes a plastic strip, a layer of ink printed on a surface of the plastic strip, and a layer of pressure-sensitive adhesive. The tape can be incorpora

A tape or label for sealing a container that provides visual evidence if the seal is forced open or cooled below a breakdown temperature. The tape includes a plastic strip, a layer of ink printed on a surface of the plastic strip, and a layer of pressure-sensitive adhesive. The tape can be incorporated into a bag for sealing the bag closed. The tape includes an ink layer that is sandwiched between the plastic strip and the adhesive layer. The adhesive can be secured to portions of a bag to seal it closed. If the seal is forced open, the ink layer visibly delaminates from the plastic strip. The adhesive layer and the plastic strip are chosen to have different rates of shrinking when cooled, so that when the tape is cooled below its breakdown temperature, the ink layer delaminates. In an alternative embodiment of the tape, two layers of ink are printed onto the plastic strip. The first layer of ink is clear and is printed onto the untreated plastic strip in a pattern. The second layer of ink is opaque and is printed uniformly over the plastic strip and the clear ink after the plastic strip is treated.

대표청구항 ▼

A tamper-evident tape for use in forming a closure for a security bag which will provide a visual indication of both opening of the closure and cooling of the closure below a breakdown temperature even if the closure is not opened, said tape comprising: an elongate flexible plastic strip being adapt

A tamper-evident tape for use in forming a closure for a security bag which will provide a visual indication of both opening of the closure and cooling of the closure below a breakdown temperature even if the closure is not opened, said tape comprising: an elongate flexible plastic strip being adapted to be secured to one wall of a bag at an opening into the bag and having one surface thereof adapted to face another wall of the bag, said plastic strip having a first rate of thermal contraction or expansion, a layer of ink applied to first portions of the surface of said plastic strip adapted to face the other wall of the bag and having an initial adhesion to that surface of said strip, said initial adhesion being lost upon separation of said ink layer from said plastic strip and said ink layer thereafter having no adhesive affinity for said strip, a layer of adhesive applied to the surface of said strip having said ink layer thereon, including second portions thereof not covered by said ink layer, such that said ink layer is between said strip and said layer of adhesive, said adhesive layer having an adhesive tack at temperatures above a glass transition temperature at or below which said layer of adhesive loses its tack and being adhered to said strip and to said ink layer so long as said adhesive layer has the adhesive tack, said adhesive layer being adapted to contact and adhere to the other wall of the bag to close the opening into the bag to provide a secure closure therefor, said adhesive layer having a second rate of thermal contraction or expansion different from said first rate of contraction or expansion of said plastic strip, said ink layer having a greater adhesion to said adhesive layer than its initial adhesion to said plastic strip and said adhesive layer having a greater adhesion to said plastic strip and for the other wall of a bag than said initial adhesion of said ink layer to said plastic strip so that said ink layer will separate from said plastic strip before said adhesive layer will separate from said plastic strip and will give a visual indication upon separation of said ink layer from said plastic strip, and said tape having a breakdown temperature substantially lower than ambient temperature but higher than said glass transition temperature of said adhesive layer, below which said initial adhesion of said ink layer to said plastic strip is lost because of said differential rates of contraction or expansion and said ink layer will separate from said plastic strip.