Study On Preparation Technology Of Pigment Blue Gel Ink

The production and yield scale of gel pen in China exist the largest in the world.Although our country's pen industry is big but not strong,due to the shallow of technology awareness about domestic gel ink,high-end products still rely on imports.Therefore,achieving a comprehensive localization of gel ink was essential to strengthen independent research and technological innovation.Based on previous research experience of our group on carbon black gel ink,the basic knowledge,composition and research background of gel ink were first reviewed,and then analyzed current stage the technical difficulties in the process of research,namely phthalocyanine blue particles dispersion stability of pigment dispersion system,optimization rheological parameters and writing performance of gel ink.The choice of blue pigment was an important step in the development of gel ink,whose type and adding quantity are directly related to the dispersion stability of phthalocyanine blue slurry and gel ink.The particle size distribution and dispersion stability of different types of phthalocyanine blue slurry were studied by using ? and ? form phthalocyanine blue(15,15: 1,15: 2,15: 3,15: 4) as the colorant.And it was explored that the gel ink with different types of phthalocyanine blue slurry influenced the writing performance and dispersion stability.The dispersion stability of the gel ink was investigated by using the phthalocyanine blue 15: 3 with better performance.The relationship between the different additions and the rheological parameters(apparent viscosity,thixotropic value,thixotropic loop area and yield stress)of the gel ink was discussed.The results turned out that the pigment slurry and gel ink showed the best performance when the optimal dosage of phthalocyanine blue 15: 3 was7.5 wt.%.The dispersion stability of the pigment depended largely on the preferred dispersion resin,and its different additions will directly affect the particle size and dispersion of the pigment and the stability of the gel ink.Taking the slurry and gel ink as the object of study,the effects for different ratio of pigment to resin on the performance of the two systems were studied.In the aspect of slurry,the dispersion regularity with the grinding time and stability was studied.In the aspect of gel ink,the relationship between the rheological parameters(apparent viscosity,thixotropic value)with the amount of thickener added under different ratio of pigment to resin was explored.The results turned out that the pigment slurry and gel ink showed the best performance when the optimal dosage of ratio of pigment to resin was 3:1.In order to improve the performance of the whole needle-type gel ink,this paper studied the thickening results with two hydrophobically modified acrylicacid swelling thickeners under the two ratios of pigment to resin affectted the higher thixotropic values.The influence of the amount thickeners on the gel ink rheological parameters(thixotropic loop area,yield stress)was found.The optimum proportion of ratio of pigment to resin and compound thickeners was investigated from the aspects of rheology and particle dispersion stability by high speed centrifugal and constant temperature heating experiment.The results turned out that the gel ink solid-liquid separation degree was smaller and microscopic dispersion was better when the adding quantity of thickener ALCOGUARD 5800 and T-938 were 0.4 wt.% and 1.0 wt.% with the ratio of pigment to resin(3:1).It also showed that there was a stably dynamic competitive adsorption to pigment particles between dispersion resin and thickener.So the gel ink behaved a stability state.Surfactants favored the pigments wetting,dispersing and improving gel ink writing performance.In this paper,the effects of different contents of single and compound surfactants on the rheological parameters(apparent viscosity and thixotropic value)of gel ink were investigated with surfactants with different HLB.At the same time,explored the relationship between the different surfactant types and stability,and established the correlation between stability and writing performance.The results turned the rheological performance and writing performance were matched to those of Japanese Mikuni ink when the gel ink adding quantity of OP-7 and OP-20 were 0.4 wt.% and 0.4 wt.%.