The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 16, 2025
Filed:
Aug. 28, 2020
Societe Bic, Clichy, FR;
Universite DE Haute Alsace, Mulhouse, FR;
Centre National DE LA Recherche Scientifique, Paris, FR;
Olivier Albenge, Clichy, FR;
Romain Metillon, Clichy, FR;
Karine Mougin, Paris, FR;
Feriel Ghellal, Clichy, FR;
Arnaud Spangenberg, Mulhouse, FR;
Société BIC, Clichy, FR;
Universite de Haute Alsace, Mulhouse, FR;
Centre National de la Recherche Scientifique, Paris, FR;
Abstract
The present invention concerns a process for preparing in situ an aqueous gel ink with fixed color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink comprising reducing agent chosen in the group consisting of citric acid and/or derivatives of citric acid, (ii) adding a solution of gold salts, (iii) adding iron powder, (iv) adding polyvinylpyrrolidone to obtain an aqueous gel ink with fixed color, wherein the steps (ii) and (iii) can be interchanged. The present invention also relates to an aqueous gel ink with fixed color obtained according to the process of the invention, comprising citric acid and derivatives, gold nanoparticles, and iron powder. The invention finally concerns a writing instrument comprising an aqueous gel ink with fixed color according to the invention.