●Water-based paint general-purpose wetting agent Use
-Aqueous coatings and inks
-Industrial cleaning agent
In the process of oxidative polymerization of dry oil, many side reactions occur, some of which promote polymerization, but most of the side reactions break fatty acids to form low-molecular acids, such as formic acid and acetic acid, and also produce aldehydes, ketones, alcohols, etc. Volatile substances such as esters, carbon dioxide and water. It polymerizes during film formation
During the induction period, the formation of peroxides, the decomposition and polymerization of peroxides, the absorption and viscosity of oxygen, and the viscosity of oxygen dissolved in oil. Until the layer is destroyed, the paint film loses its flexibility and toughness and becomes brittle, resulting in chalking, cracking, and peeling.
The approximate process of time oil drying.
The oxidative polymerization of oil-based paint in the drying process of drying oil can be greatly accelerated after adding some metal soaps. The accelerated polymerization mechanism is not yet fully understood. montan glycol wax It is generally believed that it has four functions:
① shorten the induction period;
② increase the rate of oxygen absorption Speed up;
③Promote the formation and decomposition of peroxides;
①Reduce the oxygen demand of polymerization.
The most researched on the mechanism of drier accelerating auto-oxidation drying is cobalt soap. The mechanism proposed by Muller is the repeated conversion of the valence of cobalt Co 2+–Co+–Co. Girard et al. confirmed this with spectroscopic methods.
Its data suggests that the drier and the unsaturated part of the ester bond form a weak coordination compound, which is accompanied by an increase in conjugated bonds. It has been confirmed that this is the key to determining how fast the ester absorbs oxygen. It has been found that in the presence of cobalt octoate, the activation energy required to absorb oxygen is 5.44 kJ/mol, while it is 43.10 kJ/mol in the absence of cobalt. These studies further show that cobalt has a catalytic effect on oxygen absorption and drying processes. Cobalt soap acts as a drier through the change of metal ions. It catalyzes the acquisition of oxygen, the release of protons, the activation of double bonds, the decomposition of acids, and the decomposition of peroxides through their own changes.
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