Polymerization method is used to directly prepare electrostatic copying toner. The main methods include suspension polymerization [1,2] interface/radical polymerization [3,4] agglomeration treatment method [5], etc. The suspension polymerization method uses water as the reaction medium, and the cost is low. No pollution, no organic solvent recycling problem; and the polymerization reaction product can be put into use after washing and drying, the process is simple, the production cycle is short, and the energy consumption is low. This paper uses a special dispersion equipment process and dispersion system to obtain the granularity by suspension polymerization. 10μm electrostatic copying powder (Magenta yellow blue), the use of the machine to achieve the desired effect of this article discusses the disperse equipment process conditions dispersion system selection, similar research has not yet seen in the literature reported
1 Experimental section
1.1 Experimental raw materials
Monomer: Styrene butyl acrylate; Initiator: Azobisisobutyronitrile; Dispersant: macromolecular dispersant D, dispersing aid surfactant DY, all above chemically pure, various dyes are pure industrial
1.2 Experimental Process and Formula
Initiator and other additives are added to the mixed monomer to dissolve; this monomer additive mixture is added to deionized water containing a dispersant, etc., in a high shear mixing emulsifier (homogenizer) (manufactured by Jiangsu Qidong Changjiang Machinery Factory) Stir pre-dispersed; reactor heated to 85 °C, constant temperature reaction 8 ~ 10h, the product washing separation reaction system basic formula as shown in Table 1
1.3 Test
The toner particle size test was performed using a Coulter counter [6], manufactured by HIALEAH FLORIDA USA; the surface tension was measured using an interfacial tension meter, manufactured by Chengde Material Testing Machine Factory; and the liquid-liquid dispersion was observed with a microphotographer. The photograph was taken, type 2A, Shanghai Camera factory manufacturing
2 Results and Discussion
2.1 Choose the homogenizer for pre-dispersion theory basis and test results
In this paper, a powder with a particle size of about 10 μm is prepared by a suspension polymerization process, which is smaller than the particle size of 50 to 2000 μm obtained by conventional suspension polymerization processes. Therefore, a special dispersion equipment process and dispersant system must be adopted. The particle size of the powder depends largely on the liquid solution. Dispersion process Dispersion phase monomer droplet size
Walstra[7] studies on the dispersion effect of ordinary stirring equipment, ultrasonic equipment and homogenizer show that the homogenizer among the three has the best dispersion effect.
Based on this, we adopt a process in which the mixture of monomer phase and water phase is sufficiently dispersed under a homogenizer before the polymerization reaction to make it close to the required particle size, and then the polymerization reaction is performed. The polymerization reaction process is performed by selecting an appropriate dispersant to help dispersant and stir By inputting energy and the like, the droplets of the monomer phase obtained by the predispersion substantially do not coalesce and take place, and finally the toner having a droplet size close to that of the monomer phase is obtained. FIG. 1 shows the reaction system with the same composition passing through and without predistortion through the homogenizer. The resulting toner particle size distribution shows that homogenizer dispersion plays a decisive role in reducing toner particle size.
Curve 1 - Homogenizer Predispersion; Curve - 2 Unhomogenizer Predispersion