| CPC C09D 11/17 (2013.01) [B22F 9/24 (2013.01); C07C 69/618 (2013.01); B82Y 30/00 (2013.01); B82Y 40/00 (2013.01); C08K 2003/0806 (2013.01); C08K 2003/0831 (2013.01)] | 19 Claims |
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1. A process for preparing an aqueous gel ink with fixed color comprising the steps of:
(i) preparing a gel-based matrix of aqueous ink;
(ii) preparing an aqueous suspension of gold or silver nanoparticles with fixed color by mixing gold or silver salts with:
water,
a derivative of alkaline earth metal,
an ester of retinol of formula (I):
![]() wherein R is an optionally substituted C1-C6 aliphatic group, and
optionally, a carbonate;
(iii) adding under stirring the aqueous suspension of gold or silver nanoparticles obtained in step (ii) to the gel-based matrix of aqueous ink obtained in step (i), thereby obtaining an aqueous gel ink with fixed color with gold or silver nanoparticles dispersed therein.
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