08-03-2023 дата публикации
Номер: EP4143378A1
The present invention concerns a tracking dyeing method for the colouring or dyeing a natural fibre to be marked or identified, comprising the following steps: k) preparing a natural fibre in a dye tank; L) adding a siloxane agent in said tank; m) dispersing a liquid colouring solution comprising a pigment in said tank; n) heating said dye tank comprising said natural fibre, said siloxane agent and said colouring solution at a temperature of between 50 °C and 70 °C, preferably at 60 °C; o) keeping said temperature constant for a time comprised between 1 and 3 hours, optionally for a time of two hours; wherein said pigment is a piezochromic pigment, comprising: - an inorganic matrix having a lamellar conformation, - an organic filler configured to be intercalated or absorbed between the lamellae of said inorganic matrix, said pigment having a first configuration, at a first pressure value (P1), wherein said inorganic matrix lamellae are spaced apart and at least one organic filling layer is positioned between two of said layers, and a second configuration, at a second pressure value (P2), said second pressure (P2) being higher than said first pressure (P1), wherein said inorganic matrix lamellae are close together allowing a molecular aggregation of said organic filler, said molecular aggregation generating a change in pigment coloration such that, in a configuration of use of the pigment applied on the support surface, when a compression is applied on a portion of the treated support surface, the pigment changes from said first to said second configuration, resulting in a change in coloration of the portion of treated surface that has undergone compression with respect to the rest of the treated surface that has not undergone compression, allowing a marking or identification of the authenticity of the treated support surface, said molecular aggregation generating a change in pigment coloration such that, in a second configuration of use of the pigment once activated ...
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