| 摘要 |
PURPOSE:To produce a paint additive having excellent corrosion resistance, by adding a cationic surfactant to specified clay mineral to make it lipophilic and then adding tannic acid and an aq. alkaline soln. thereto. CONSTITUTION:Smectite and/or vermiculite clay mineral having a thickness of 0.01-0.1mum, a size of 0.1-1mum and an aspect ratio of not lower than 10 are/is dispersed in ion exchanged water in an amount of at least 10 times that of the clay mineral to obtain a dispersion. 10-40% cationic surfactant is added thereto and the mixture is left to stand for 24hr or longer to make the clay mineral lipophilic, thus obtaining a clay mineral mixture which is made org. by the above treatment and in which the surfactant is electrochemically bonded to the surface of the clay mineral or the interlaminar surface thereof. 3-10% tannic acid and an aq. alkaline soln. are added to the mixture to adjust the pH to 8-12, whereby tannic acid is electrochemically bonded to the clay mineral through the surfactant to thereby impart corrosiveness. The product is washed with water to remove unbonded surfactant and unbonded tannic acid.
|
