Are there additives which, when incorporated in waterbased paints, act as antifoam agent and at the same time prevent flocculation ?
The antifoam effect ominates in systems such as mineral and paraffin oils, modified polyglycol ethers and boron esters such as triethyl borate. Their effectiveness is due to the fact that they more or less neutralise the original surface tension of the paint, so that foams disappear.
Besides the antifoam effect there occurs stabilisation of the pigment dispersions with substances like partial esters containing hydroxyl groups, fatty acid derivatives ( including unsaponifiable ones ), various surfactants and the low molecular weight silicone.
A pure deflocculating agent is aminomethyl phosphonic acid. In addition there are silicone free combinations such as triglyceride oxyethylene condensates, polyalkylene glycols as well as condensates based on polyoxyethylene and polyoxypropylene.
The stabilisation of the degree of pigment dispersion will then be based, depending on ionic character, stricture and molecule size on charge-related repulsion of the pigment particles or on the entropic repulsion of the adsorption shells which form the anti flocculation agents.
