Process for the manufacture of paper sheets for paper money, paper securities and other items, and sheets made by this process

摘要

The paper pulp is made to contain heat-sensitive dyes which are visible by external inspection and whose colour varies with a variation in their temperature. Preferably, the paper pulp will be made to contain incorporated components such as fibrils, laminar fragments (chad), threads or chips, these components being dyed with heat-sensitive dyes.