Patent ID: 11920047
Assignee: SOCIÉTÉ BIC
Field: Basic materials chemistry (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. A method for preparing a thermochromic water-based gel ink composition comprising the steps of:
(i) preparing a thermochromic pigment composition by mixing:
(A) at least one electron-donating color-developing organic compound,
(B) at least one electron-accepting compound, and
(C) at least one color change temperature regulator,

(ii) encapsulating the thermochromic pigment composition prepared in step (i) in presence of a copolymer surfactant comprising at least one monomer of maleic anhydride, to generate an aqueous suspension of thermochromic pigment microcapsules,
(iii) acidifying the aqueous suspension of thermochromic pigment microcapsules obtained in step (ii) at a pH lower than or equal to 4.6, by adding a monocarboxylic or polycarboxylic acid,
(iv) preparing a thermochromic water-based gel ink composition comprising the aqueous suspension of thermochromic pigment microcapsules obtained in step (iii) and at least a gelling agent.