Preparation And Printability Of Waterborne Polyurethane Plastic Printing Ink

Waterborne polyurethane ink has been widely concerned and applied because of its excellent environmental performance,but its printing suitability on plastic film is poor.The main factor affecting the performance of waterborne ink printing is the performance of the linker.Therefore,it is of great significance to develop water-based polyurethane connection material with excellent attachment performance and stable color reproduction with applicable ink formula for the preparation and promotion of water-based polyurethane plastic printing ink.This paper will firstly compare the printing suitability of waterborne polyurethane ink on paper and plastic film and obtains the key problems of waterborne polyurethane ink’s poor printing suitability on plastic film,followed by the influences on waterborne ink’s printing suitability studied from three directions: kaolin filler,content of waterborne polyurethane ionic group and degree of crosslinking.The main research contents are as follows:The water-based polyurethane ink was prepared and sampled on different printed paper and plastic film respectively.The water-based ink’s water resistance,adhesion and color reproduction were compared and analyzed.It is concluded that after the printing of waterborne polyurethane ink on plastic film,before and after wetting,the color difference △E>10,and the adhesion fastness is about 70%.Compared with the color reproduction of paper,the color difference △E>10,which exposes the ink is poor in water resistance,adhesion performance and color reproduction and mainly needs to be improved from the adhesion performance.To explore its impact on the printability of waterborne polyurethane ink,an appropriate proportion of kaolin filler was added to the ink.The addition of kaolin slightly improved the adhesion of water-based ink on offset paper and copper paper,and its color reproduction was stable.However,the adhesion of water-based ink on PET film was not improved,and its color reproduction ability performed badly on PET film.The ink with 10-12% kaolin content can meet the requirements of paper printing and can be applied in Guangdong Tianlong Ink Co.,Ltd.,but still it is not adaptive to PET film.In the experiment,a series of polyurethane emulsions with different ion groups were synthesized using different DMPA contents to investigate their adhesion properties on PET films.The results show that with the increase of DMPA content,the surface tension of the emulsion and the contact Angle on PET film become larger,which will make the wettability of waterborne polyurethane on PET film become worse.With4wt% DMPA content,the peel strength reaches the maximum,so as the wettability,and the waterborne polyurethane can be attached well to PET plastic film.Also,emulsions contains different crosslinking densities were synthesized by crosslinking with different DETA contents.Through the study of their properties,results show that with the increase of DETA content,the T-shape peel strength of waterborne polyurethane increases first,and then decreases.With 2wt% DETA content,the peel strength reaches 2.75N/15 mm,which is significantly improved compared to those without DETA crosslinking.The ink,configured with ion group content and crosslinking density waterborne polyurethane emulsions that differs from the previous content,was investigated from viscosity,fineness,initial drying,water resistance and adhesion fastness.The conclusion is,in WPU-3 ink,its waterborne polyurethane binder not only has DMPA to improve the content of the ion group,but also EDTA for crosslinking,and under the superposition of the two modifications,its adhesion fastness on the PET film reaches 98%,indicating its excellent adhesion ability and color reproduction ability on PET film,which meet the printing requirements and can be applied in Guangdong Tianlong Ink Company.Also it has certain reference significance for the preparation of waterborne polyurethane plastic printing ink.