| Ink jet recording is a non-impact digital printing technology, it combines digital technology with traditional printing technologies, and has made a great success. Now, with the increasing of PC and printer, the demands for ink-jet ink increase sharply. Ink jet inks using water-soluble dyes usually show low water resistance and low light resistance, so it is an inevitable trend to introduce pigment into ink jet inks, to overcome the shortcomings of using dye-based inks. In order to maintain the dispersion of pigment stable, it is essential to synthesize the dispersants with high-tech features. To meet the requirement of environmental protection, water is used as the solvent of ink. And the core issue of preparing pigment based ink is as the follow: How can we synthesis a kind of polymer that can disperse the pigment and keep the pigment in water steady? On the one hand, the polymer synthesised can being a dispersanthas because of the surfactant characteristics; On the other hand, the polymer can also play the traditional role of ink binders.In the research acrylic-styrene resin was synthesized through semi-batch solution polymerization process, adopting styrene (St) as one of the comonomers and methacrylic acid (MAA) as the other one, takes AIBN as the initiator and takes n-butanol as the solvent. By discussing initiator's amount, reaction temperature, solvent and monomers' allocated proportion, instilment time to the resin's performance influence, such as the content of the resin, the conversion rate and the visconsity. We obtain the best formula of synthesis water-soluble acrylic resin for water-based inks: St:MAA(mole rate) is 1:2, the AIBN amount used is 1.5%, the solvent :monomer (mass ratio) is 1:1 and the best conditions: the monomer instilment time is 2h, the heat preservation time is 2h, the reaction temperature is 80℃。The polymer synthesised isn't soluble in water unless it was prepared through the reactions of amination. Ethanolamine is used as the neutralizer.We used the aminated polymer to disperse Pigment Red 122 , the relationship between the ratio of pigment to base material and the stability of pigment dispersion were discussed. Changes of particle size owing to emulsification time were also investigated.We obtain the best formula of synthesis pigment dispersion for water-based inks: the ratio of pigment to base material is 3:1, high-speed emulsifying time was 1h.The water-based inkwas prepared with the dispersant synthesized.And the index which obtained by checking funetions of the inks finallydemonstrates that many can reach the National Standards.
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