| In recent years, aluminum foil was widely applied in many areas such as food,medicine, and aerospace for their excellent lightweight, high seal performance, wellencapsulated performance, environmental protection and so on. Food industry andpharmaceutical industry were the major market in aluminum foil packing, which askedfor the printing ink having the properties of good adhesion in the non polar and smoothaluminum foil, the rapid preliminary drying process, water resistance, good water wearresistance, after tackiness resistance and so on. However, with the requirement ofpeople gradually improved in health, and put forward the new criterion of aluminumfoil package printing industry in food, cigarettes and wine, pharmaceutical industryand so on, tradition solvent aluminum foil ink contented volatile organic solvents suchas aromatic hydrocarbons, ketones, alcohols or esters, which had the disadvantages inenvironment and human health, for this reason, the study and development of the newenvironmental waterborne aluminum foil ink had became the primary question inpresent aluminum foil printing ink industry.At present, the properties of the waterborne gravure aluminum foil printing inkpossess many defects, such as the weak adhesion in the aluminum foil, the lowglossiness of ink coating after printing, slow dryness rate, the weak tackiness andwater resistance, which limit the waterborne gravure aluminum foil printing ink widelyapplied in food and pharmaceutical aluminum foil package, and the high-gradealuminum foil package which has the high requirement in sanitation. This paper hasstudied the synthesis of the waterborne polyurethane-polyacrylate composited hybridand discussed the application in the formula of waterborne gravure aluminum foilprinting ink. The full paper has three parts:In the first part of this article, the structure, properties, application andmodification of waterborne polyurethane were outlined. Furthermore, the formationand application of the water-borne polyurethane-polyacrylate composited hybridsystem were emphatically introduced. At the same time, the present approaches forsynthesizing the polyurethane-polyacrylate hybrid were also introduced.In the second part, Ethylenediamine extended and ethylene glycol methacrylatecapped anionic waterborne polyurethane (EDAWPU and VLWPU) contained thecarboxyl groups which served as internal emulsifier were made by acetone process,respectively. In order to improve the performances of WPU film, the uncrosslinked and crosslinked polyurethane/polyacrylate (UCPUA and CPUA) composite emulsions withcore and shell structure were prepared via soap-free emulsion polymerizationtechniques. The chemical structures of the EDAWPU and VLWPU were confirmed byFTIR. TEM images showed the core-shell structure of the CPUA whose core and shellregions were occupied by acrylic polymer and polyurethane, respectively. The averagemolecular weight of CPUA and UCPUA were310934and86522, respectively. TGAshowed that the initial decomposed temperature of CPUA (276.12℃) presented betterthermal stability than that of UCPUA (269.3℃). The higher glass transitiontemperatures were observed in CPUA film from DSC curves. The tensile strength wasalso improved by cross-linking in CPUA film. All the results showed that the CPUAexhibited superior performance properties in terms of hardness, adhesion, flexibility,glossiness and water resistance.In the third part, the waterborne aluminum foil ink major vehicle was made by theCPUA, acrylic resin dispersion and styrene-acrylic ester emulsion for their excellentperformance. Where-after, the integral performances of waterborne aluminum foil inkwere further improved by adding flow ping agent, smooth agent, and coalescing agent.The result shows that the fundamental characteristics of the new developed waterbornegravure aluminum foil printing ink had meet the basic standard, but the rate of alldrying, the weak tackiness and water wear resistance were also necessary to improve inthe later time. |
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