Study on the preparation and performance of water-based transparent iron oxide red dispersion (2)

1 shows that when the amount of dispersant is 4.0% to 5.0% of the amount of transparent iron oxide red, the stability of the preparation of water-based transparent iron oxide red is the highest and the L value is the lowest. When the dispersant dosage is less than 4. 0%, can not all occupy the transparent iron oxide red surface, the particles between the rejection force is small, resulting in the transparent iron oxide red without attachment to the dispersant again gathered, however, when the dispersant added too much, due to the bridge phenomenon of the dispersant, thermal storage, the transparent iron oxide red particles occurring on the bridge can easily be deposited, resulting in poor stability of the system.
2. 2 The effect of the wetting agent on the performance of the dispersionSelecting a wetting agent that matches the transparent iron oxide red surface can speed up the wetting of the water on its particle surface, thus improving the grinding efficiency and effect. Table 2 shows the effect of wetting agent on the performance of water-transparent iron oxide red dispersion.As can be seen from Table 2, after Wa prepares water-based transparent iron oxide red dispersion heat storage for wetting agent, the viscosity change rate and particle size change rate are the smallest, and the stability is obviously improved. This may be due to Wa's HLB value and transparent iron oxide red pigment HLB value is close, on the one hand, improve the dispersion efficiency of transparent iron oxide red in the water solution containing Wa, on the other hand, Wa molecular chain adsorption in fa and transparent iron oxide red adsorption space, enhance the strength of the hydration layer, thus improving the storage stability of the dispersion. Wb's hydrocarbon chain is longer than Wa's, and the HLB value is much lower than the HLB value of transparent iron oxide, resulting in the wetting agent on the pigment surface can not be evenly adsorbed, and even more wetting agents flow out of the solution, and the dispersant adsorption, reducing the dispersion efficiency of the dispersant to transparent oxidationiron red.2 is the effect of the amount of wetting agent on the performance of the water-transparent iron oxide red dispersion.As can be known from Figure 2, with the increase of Wa dosage, the L value of the prepared water-transparent transparent iron oxide red dispersant L is reduced and then increased, and the viscosity change rate, particle size change rate and transparency of wetting agent dosage are the best at 0.6% to 1%. When the amount of wetting agent is reasonable, it promotes the dispersion effect to a certain extent, and excessive wetting agent will cause the competitive adsorption phenomenon with the dispersant on the pigment surface, so that the dispersant can not be fully adsorbed on the pigment surface, comprehensive consideration, Wa reasonable dosage of 1%.3 Effect of pigment content on dispersion performanceTable 3 shows the effect of pigment content on dispersion performance.By Table 3, it can be known that when the pigment content is 10%, the rate of change of the thermal storage particle size is as high as 21.7%, and the heat storage caused a small number of particles subside phenomenon, this is because when the transparent iron oxide red content is low, the system viscosity is low, resulting in large particles in the system after thermal storage subsidion. When the transparent iron oxide red content is higher than 20%, the viscosity of the system increases rapidly, and the rate of change of storage viscosity increases sharply, which may be due to the increase in the content of transparent iron oxide red pigment, the reduction of pigment particle spacing in the dispersion body, the dispersion of particles easily and the dispersion medium in the system The formation of a tight aggregate, bridges or adsorption between the aggregates caused a mesh structure and make the viscosity change rate after storage greatly increased, pigment content of 20%, the preparation of water-based transparent iron oxide red dispersion is in good condition, high stability. It can be seen that 20% is the preparation performance of excellent transparent iron oxide red dispersion of the preferred pigment content.2. 4 Effect of grinding frequency and time on the performance of water-based transparent iron oxide red dispersionFigure 3 shows the effect of the preparation process on the performance of water-based transparent iron oxide red dispersion. Among them, the pigment content of 20% (accounting for the mass fraction of the dispersion system), the amount of dispersant and humidifier, respectively, 4% and 1% of the amount of pigment used.Figure 3 shows that the increase of grinding frequency, the transparency of water-transparent iron oxide red dispersion is faster to reach the highest, indicating that the higher the grinding frequency, the shorter the time for the dispersion to achieve dispersion and reunion balance, so the experiment selected 45 Hz as the preferred grinding frequency for the preparation of the dispersion, and 45 min as the better grinding time.3 Conclusion Through the study of the preparation and performance of transparent iron oxide red dispersion, dispersants, wetting agents, grinding frequency and grinding time have a great impact on the performance of transparent iron oxide red dispersion, and the process of preparing water-based transparent iron oxide is better for the use of 20% pigment content (which accounts for the mass fraction of the dispersion system), Fa and Wa dosage of 4% and 1% of pigment dosage, respectively.