Security enclosures

A laminate for use in forming a security enclosure, the laminate comprising a first layer of an insulating material carrying a linear electrically responsive element on at least one surface thereof, a layer of low tensile strength material having lower cohesion than adhesion being located between the first layer of insulating material and the electrically responsive element a second layer of insulating material being adhered to and covering the electrically responsive element, the element being arranged in a configuration on the surface so dividing the surface that attempted penetration of the laminate changes an electrical characteristic of the element, which change may be detected by an appropriate electrical circuit and an attempt to remove the second layer of insulating material to gain access to the linear electrically responsive element will result in breakup of the low tensile strength layer and thus damage the element and produce a detectable change in said electrical characteristic of the element.

A security enclosure comprising a flexible laminate which is folded and joined at overlapping edge portions to define the enclosure, the laminate comprising a flexible first layer of insulating material extending over the whole of the area of the enclosure and carrying lines of electrically responsive material on one side thereof, a further layer of insulating material being adhered to and covering the lines with the lines at at least one of the overlapping edges of the laminate being exposed beyond and adjacent edge of the insulating layer, the lines being arranged in a configuration on the surface so dividing the laminate that attempted penetration of the enclosure changes an electrical characteristic of the lines, means being provided for detecting said changes in the electrical characteristics of the lines and a layer of low tensile strength material being provided between the first layer of insulating material and the lines of electrical responsive material at said at least one of the overlapping edges, the low tensile strength material having lower cohesion than adhesion and any attempt to separate the overlapping edges to gain access to the enclosure resulting in breakup of the low tensile strength layer and damage to the lines to produce said detectable change.