Study On Offset Fountain Solution

The nonionic surfactant fountain solution is low surface tension and new solution which use nonionic surfactant instead of alcohol. It has become perfect fountain solution owing to its low surface tension and good wetting and reducing the dosage. The purpose is to choose suitable nonionic surfactant as additives of fountain solution and configure a new one that has good wetting and anti-hard water, and stable performance.This paper chooses AEO₇, Tween-80, APG0810, L64 from the numerous surfactants as additives according to printing technical principle and printability and the relation of configuration and character of surfactant and the value of HLB. Through measuring the cloud point and hard water stability and critical micelle concentration of surfactant the Tween-80 and L64 was chose as additives owing to its higher cloud point and stable in hard water and suitable surface tension.Tween-80 was blended with L64 then the wetting of mixed system was measured. Nonlinear regression was used to deal with experimental data and the mixing ratio and wetting was obtained. Then programming method was used to obtain best ratio when the best synergy and the dosage of main additives was determined.The emulsion rate and stability of emulsion ink is an important indicator to evaluate the character of fountain solution. Polar organic interacted with water-soluble polymers and come into complex, so the interfacial film of ink and water was strengthened and the stability of emulsion ink was improved. The glycerol and polyethylene glycol200 was chose as additive because of its good wetting and hygroscopic. The dosage of additives of glycerol and polyethylene glycol200 was determined by uniform experimental design.The pH value of fountain solution has an important effect on transfer of offset ink which too low or high will not be suitable for wetting plate. Fountain solution should have pH buffer in order to maintain pH stability of fountain solution. Citric acid and sodium citrate that have cleaning performance and less side-effect was chose to make up of buffer solution. Finally, some of the basic properties of configuration solution were measured.The results show that configuration solution has strong anti-hard water, better wetting and buffer and meets the requirements of printing.