Toner production by in situ emulsion polymerization: Investigation of the effect of reaction temperature and stirrer speed

In recent years, toner-based printers have found many applications for ease of use, economical, high speed and quality. Therefore, many attempts have been made to produce toner by various methods such as suspension polymerization and emulsion aggregation. But in all these methods, despite the proper color properties and particle size, the reaction conversion is low.

In the present study, in situ emulsion polymerization method based on styrene and butyl acrylate monomers in the presence of carbon black has been used to produce toner with a conversion above 75%. In this regard, the effect of polymerization reaction temperature and stirrer speed on conversion at different times, particle size and particle size distribution, thermal and color properties of the final product were investigated. Color measurement was performed to evaluate the color characteristics. Also, the microstructure of the synthesized toners was evaluated using scanning electron microscopy.

The results show that in situ emulsion polymerization method while having the proper conversion of the reaction in the range of 75-90% is well able to create the suitable color characteristics and particle size distribution for the toner. All toners produced had a particle size distribution and a spherical shape that was unaffected by the reaction temperature and stirrer speed. By increasing the polymerization temperature from 70℃ to 80℃, resulted in a higher conversion, but the increase in stirrer speed had a dual effect on the conversion. Sticking of spherical particles with each other was observed by increasing the temperature to 90℃. The sudden addition of a monomers to the reaction media and using batch process resulted in the observation of two glass transition temperatures. This type of toner synthesis can be a guide for future research to produce toner with the highest conversion.