| 配方类型： |
EMULSIONS AND DISPERSIONS |
| 配方说明： |
Tar Emulsion |
| 配方组成： |
"RT-12" Tar/50
"Ethomeen" C-25/0.625
"Carbopol" 941/0.125
Water/50
Sodium Hydroxide (10% sol'n)/0.375 |
| 配制方法： |
Carefully disperse the Carbopol 941 in the water in a jacketed vessel, and then add the sodium hydroxide and amine. Heat both the water mucilage and the tar to 65'C. Slowly add the molten RT-12 to the hot mucilage with vigorous mixing (A mixer such as a medium-speed Eppenbach homogenizer is recommended.) The mixing step is critical. With very high shear mixing, the tar particles are extremely small, and the emulsions are very smooth. Films deposited from such emulsions are difficult to dry, however, because an impermeable layer forms on the top. By contrast, emulsions formed with moderate shear have relatively large tar particles but dry evenly and rapidly.
After the last of te tar has been added, mix briefly to ensure homogeneity. It is then very important to rapidly cool the emulsion without further mixing by running cold water through the vessel water jacket. The transition of the RT-12 from liquid droplets to solid particles requires careful handling. On a production basis, conventional shock cooling |
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