Preparation,Characterization And Application Of Waterborne Epoxy Modified Acrylic Resin For Plastic Substrate

As people's awareness of environmental protection increases,waterborne inks are favored by the packaging and printing industry.However,when applied to plastic substrates with low polarity,waterborneinks often have the disadvantages of low adhesion and poor water resistance.Inkjet printing can quickly,conveniently and arbitrarily form an ink layer with a required pattern.It has a wide range of applications in the fields of electronics and electrical insulation.However,inkjet printing has extremely high requirements on stability and printing fluency for waterborne inks.Printing inks for plastic films need to have the characteristics of rapid drying and film formation process to meet the needs of rapid industrial printing production.This dissertation focuses on the research of epoxy-modified waterborne acrylic resin as a binder for inkjet printing waterborne inks for PET substrates and waterborne printing inks for plastic film substrates,which has important theoretical and practical significance.(1)A waterborne epoxy-modified acrylic resin was prepared by free radical solution polymerization method using ethanol as solvent,AIBN as initiator,MMA as hard monomer,BA as soft monomer,AA and HPA as functional monomer,epoxy resin E-51 as modifier,and applied in a waterboren inkjet ink for PET film.Based on the analysis of the reaction and gel mechanism of the waterborne epoxy-modified acrylic resin,the influence of the resin formulation and process on the printing fluency and ink layer adhesion of the water-based inkjet ink was discussed,and the optimized formulation and process were obtained.The experimental results showed that E-51 was grafted to the molecular chain of acrylic resin by a free radical polymerization reaction mechanism,and the cross-linking reaction between free E-51 and the carboxyl group in the resin caused the viscosity increase of the resin an even gelation.When the amount of AIBN is 3.02?3.93%,the amount of E-51 is 4.5?5.2%,the amount of AA is15.1%,and the amount of HPA is 5.1%,based on the total monomer amount an epoxy-modified acrylic resin with good water solubility and stability was obtained.The obtained resin is formulated into a water-based inkjet ink with a solid content of 5%and a ratio to pigment of1:1.The ink showed excellent inkjet printing adaptability.The ink coating film was cured at90°C for 1 hour and showed very strong adhesion that non-fading was found after withstanding100?boiling water for 30 minutes.(2)On the basis of the waterborne epoxy-modified acrylic resin,a low-temperature self-cross linkable waterborne epoxy-modified acrylic resin was synthesized by introducing the low-temperature self-crosslinking(DAAM-ADH)system.The obtained resin can achieve low temperature(?60?)cross-linking reaction.When applied to low-polarity film inks,the film showed improved adhesion and water resistance.In view of the sharp increaseof viscosity for the resin stored in winter(the average room temperature is lower than 20°C),which affects the printing adaptability of the ink,the reasons were discussed in detail and found that the-NH₂group has a strong hydrogen bonding effect between components,forming associated molecules,thus leading to the viscosity increaseing sharply.When the amount of DAAM is 2%and the amount of A-151 is 2%,the viscosity of the resin can be controlled within 2000 c P,and the coating film has excellent adhesion and water resistance.(3)To solve the problem of excessive irritating odor caused by the volatilization of a large amount of neutralizer ammonia during the drying and film forming process when the plastic film ink is applied in the factory,the method to reduce the odor was explored.The experiment results found that when the carboxyl monomer is 8%,the amount of hydroxyl monomer was reduced to 9%,the amount of neutralizer ammonia was reduced and the irritating odor was reduced obviously.When the amount of crosslinking monomer AAEM is 3%,or the amount of A-151 is 1?2%,the film could keep good adhesion and water resistance to meet the requirements.