The Research Of The Dispersing Agent's Types For The Gel Ink's Stability And Writing Quality

Although China was the major manufacture of ball-point pens in the world, the gel pen ink which was in high technology is still rely on importing so far. Gel ink import prices had been high, had become a foreign enterprises in China gel ink pen business "profit porter", gel ink had restricted China's sustainable development of pen manufacturing industry. Thus, it was significant to promote China gel pen ink industry to develop healthily, by studying the preparation technology of gel pen ink deeply, resolving the technical difficulties in the preparation process and achieving the localized production of gel pen ink.At present, the poor stability and bad rheological properties were the big technical bottlenecks of China gel pen ink, which influenced the healthy development of China gel pen ink industry seriously. Selecting suitable dispersant not only gave pigment good dispersity in the system, but also influenced the stability and rheological properties of gel pen ink system. It was possible to realize dispersity,stability and rheological properties. There were many kinds of dispersant in the market. And the actual employ results of dispersant were influenced by the system environment of gel pen ink. Therefore, it was difficult to select suitable disperant and to research the technique of gel pen ink. The paper based on related theory and a great many experiments, we selected a serious of disperant which were suitable for gel pen ink system and made many gel pen ink whose quality achieved the world level.Accordingly, this research subject aims to achieve the independent R & D and production of black high-quality gel ink. In the present work, composition of the gel pen ink system, dispersant type, structure and dispersion mechanism are mainly discussed. The non-ionic dispersants OP, anionic dispersants 5029 and polymer dispersant K30 have been chosen. Positive and negative effects of each dispersant on the gel pen ink system are mainly studied in this paper.First, dispersing efficiency of OP, 5029 and K30 have been contrasted by micro-disperse state of color paste. Effects of each dispersant on the stability of gel pen ink have been investigated through high-speed centrifugation and heating experiments. The results showed that OP and K30 have advantage of improving dispersing efficiency and stability of system respectively.Second, effects of each dispersing agents on viscosity and thixotropic of gel pen ink have been measured via the viscometer. The results showed that anionic dispersants 5029 could keep a good balance between system stability and rheological properties. Finally, effects of each dispersant on writing performance of gel pen ink were proved through crossed line. Also, the amount of each dispersant were determined.The results showed that the stability of gel pen ink prepared by using anionic dispersants 5029 is poor. Using non-ionic dispersants OP as dispersing agent, the prepared gel pen ink could not reach the dispersity and thixotropy in the same time. If the amount of OP was decreased, the dispersity of pigment was not good; if we added too much OP, the thixotropic index of the ink system would decline and the ink had a poor rheological property. When K30 was added into the gel pen ink, the dispersity of the system was good. However, the dispersant K30 had a bad influence on the system's viscosity and thixotropy, which had a strong impact on the rheological property of the syetem. Finally, prepared by adding anionic dispersants 5029, non-ionic dispersants OP and polymer dispersant K30 as multicomponent dispersant, the gel pen ink had better performance of dispersity, stability and thixotropic. In addition, the gel pen ink added in multicomponent dispersant was smooth writing, out of ink even and all the other indexes were excellent.