| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Masahiro Green Techno, Manager, 部長(研究職)
NIMURA Isao Hodogaya Chemicals Ltd., Research Institute, President, 筑波研究所, 所長(研究職)
MOMOSE Yoshihiro IBARAKI Univ., Faclty of Engieering, Prof., 工学部, 教授 (10006314)
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| Research Abstract |
Powder coating is known as a technique, which is free from volatile organic compounds. Brushing-up of powder coating technique has been tried by using charge control agent(CCA), most of which are organic materials, to tribocharging powder coating to form coating layers with high quality with high transfer efficiency in this study
First, effects of CCA on tribocharging of coating powders was examined. For that purpose, CCA was incorporated into a polymer layer, and tribocharging characteristics of a ferrite powder with polymer coating by the polymer was measured by cascade method. The CCA free styrene-acrylic polymer sheet tribocharges the ferrite powder slightly negatively. When a positive CCA is incorporated into the polymer, the negative tribocharge of the ferrite powder increases, and a negative CCA shifis the tribocharging of the ferrile powder in the positve direction.
Next, CCA was incorporated into a triobcharging power spray gun, and change in the tribocharging of coating powders was examined. It could be confirmed that the tribocharging of coating powders was controlled by CCA.However, most organic CCAs decompose easily at relatively low temperature, which limits practical application of CCA to powder spray gun, because spray guns are usually fabricated by modlding.
If we use metal oxide powders instead of organic CCAs, we can clear the problem of decomposition of CCAs. Unfortunately, however, charge control power of metal oxides are weaker than usual organic CCAs.
In conclusiron, application of CCA to powder coating improves the tribocharging of coating powders, bringing about improvement of coated layers.
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