Printing elastic white base ink appearance quality is the external quality appearance,its includes printing white base ink appearance state, exquisite level,flow performance.Good quality printing elastic white base ink its appearance should be uniform liquid, white viscous semi-paste, delicate balance, good fluidity, shiny surface. However,the poor quality printing elastic white base ink when storage often occurs:stratified solidification, poor liquidity, water flocculation, viscosity is too large, from paste state, directly affect the quality, color, coverage, water resistance, leveling, cover rate, gloss, color yield performance ect.
There are many factors affecting printing elastic white base ink appearance quality,such as printing materials,like: resin (binder) wetting and dispersing agent,thickener, filler,formulas and production processes will have an impact on it.Qingyi analysis printing elastic white base ink appearance quality control methods to you, mainly divided into the following categories:
Choose the resin meets formulation requirements.
Resin is the most important in printing elastic white base ink formula. Different resin particle size distribution is not the same, chemical ion stability, mechanical stability is not the same, water-in-oil, oil-in-water and their hydrophilic are not the same, have a great impact on the appearance. Therefore, when choose resin, we must fully consider resin characteristics, especially resin compatibility, in order to coordination process formula filler, additives and other options.
With a good dispersant, leveling agent.
Leveling agents produced by different manufacturers, dispersants have different HLB values.
Generally dispersant, leveling agent(water) HLB value are larger, the system will reduce more viscosity; different types dispersion leveling agent with its HLB value increases, the lower viscosity to system and the greater impact to resin.
Hydrophilic dispersion leveling agent will improve printing elastic white base ink storage stability,hydrophobic dispersion leveling agent will improve printing elastic white base ink scrub resistance after film formed. Therefore, hydrophilic and hydrophobic dispersion leveling agent used in conjunction, can effectively improve printing elastic white base ink storage flexibility. If you add more dispersion leveling agent, will increase its hydrophilicity, fluidity, but it’ll reduce the water fastness, water resistance become worse.If you add too little dispersion leveling agent, it will directly affect the appearance quality, so general should be controlled at 3% -5%.
Reasonable use thickener, to improve printing elastic white base ink performance.
Currently printing elastic white base ink commonly used in thickeners are: polyacrylic acid, cellulose ethers, alkali-soluble acrylic, non-ionic associative polyurethane.
Cellulose thickener (mainly including hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose) with high thickening efficiency, good stability, but poor leveling, easy to cause mark in the screen printing , and have a certain impact on slurry gloss. Polyurethane thickener price is higher,in printing elastic whitebase ink is not much use. Polyacrylic thickener because of good leveling, not easy to produce mesh marks, doesn’t affect slurry gloss, has a good water resistance and biological stability, good compatibility,formation molecular links between particles,resulting in resin-filler-resin forms a net structure, provides a high medium-to-high shear rate, making printing elastic white base ink have a good rheology ability, make appearance present milky white liquid half cream.
Printing elastic white base ink appearance quality,it’s the product give to customers the first impression.Therefore, to do a good job appearance quality about printing paste is very important. To control printing elastic white base ink appearance quality, we must design a good formula resin, additives, fillers and other elements and use the right production process.