摘要 |
<p>A heat sensitive color-producing multi-layer coating including a first coating layer formed from a base polymeric coating composition comprising a solution of film-forming polymer, a source of polyvalent metallic ions, and at least one fatty acid or derivative thereof; a second coating layer, on the first coating layer, formed from a sensitizing coating composition comprising a solution of organic film-forming polymer, at least one fatty acid or derivative thereof, and reducing agent selected from catechol, pyrogallol, hydroquinone, diphenyl carbazides, gallic acid esters including ethyl gallate, propyl gallate and lauryl gallate, and derivatives thereof; and a third coating layer, on the second coating layer formed from a base polymeric coating composition as defined above.</p> |