Synthesis Of Two Kinds Of Polyamide Resins For Waterborne Ink

Along with human environment protection consciousness increasing, waterborne inks are attached more important to and called as new green printing materials. They have characteristics of low pollution, low volatility, unflammability, avirulence or low toxicity and low peculiar smell. Now, most of developed countries never use solvent printing inks. As the binder of waterborne inks, the capability of polyamide resin has great influence on the quality of inks.The use of polyamide resin in inks impacts to them excellent bond strength, adh- esion, gloss, and printability. These resins are widely used for the gravure, flexograhic pringting inks and informative graphics to various packaging materials, particularly for cellophane, polyethylene films, polypropylene films and so on, which are meaningful for applications. This paper aimed to develop the polymerization processing and conditions, which is meaningful for synthesis of novel polyamide resin. We studied two methods to synthesize two sorts of novel polyamide resin.Resin 1: The product was synthesized by maleic anhydride, and then esterified with pentaerythritol. The optimum reaction conditions are as follows: wt (rosin): wt (m-aleic anhydride): wt (pentaerythritol) =50:11:6; catalyst dosage:0.15% of rosin addition; reaction temprature:190±5℃; addition reaction time, 2 hours; the esterication reaction temperature, 200±5℃, the esterication reaction time, 1 hour. This water-based resin had high soften temperature, good solubility in many solvents, excellent adhesion to PE and PP film. Fine colligation performance of resin was obtained.Resin 2: at first, a water-dispersible graft copolymer was synthesized by reacting the polyamide with acrylic acid, methyl methacrylate and styrene.Acrylic acid (AA): meth-ylmethacrylate (MMA): styrene (ST) : alcohol-soluble polyamide resin (APR)= 9.9:16.5:9.2:64.4(wt). The graft copolymer solved in ethanol and n-propanol, and BPO as initiator. Through solution polymerization, a kind of polyamide resin with acid value 55 (mgKOH/g resin) was synthesized. Secondly, a proper amine, such as triethylamine, was choosed. For amination, we got polyamide resin with pH value 8.5~9.5. Lastly, at room temperature, waterborne polyamide resin emulsion was prepared using phase inversion. The deionized water was added into the flash under high speed stirs. With increasing of the amount of the deionized water slowly, the viscosity of mixture rised and then descended suddenly, stable polyamide resin emulsion was prepared. The cured film of emulsion had good water resistance and excellent adhesion to PE and PP film.The resin was characterized by IR, GPC and 1HNMR spectra. On the base of the research of the prescription of polymer, we studied the affectting factor of amount , kind of initiators and reaction temperature. With increasing the amount of the initiator, the rate of graft rised. But when the amout increased to 0.6%, the rate of graft descended. The best technics was sure: the amount of initiator was 0.5%, polymerization temperature was 90℃.