| 摘要 |
<p>PURPOSE: To decide an illegal matter on a heat sensitive sheet at a glance by setting thermal conductivity via a release layer and an adhesive layer to a specific value or less in a label in which a base material, the release layer and the adhesive layer are sequentially laminated. CONSTITUTION: In order to prevent tampering with a document made of a heat sensitive sheet, a base material 1, a release layer 2 and an adhesive layer 3 are sequentially laminated in a label to form a protective film on the surface of a printed matter in such a manner that the material 1 and the layer 2 are releasable therebetween and the thermal conductivity via the layers 2 and 3 is set to 10 (cal/sec/cm2 deg.C/cm) or less. Or, finely particulated developer and leuco dye or photochromic material for coloring with ultraviolet or infrared rays are dispersed in the layer 2 or 3 as required. According to this, the conductivity of the layer 2 or 3 is low, and the sheet is heated to effectively prevent an illegal additional writing.</p> |
