Dispex A40 Ammonium salt of an acrylic polymer Ciba Dispersing agents >> Surfactants-like >> Sodium polyacrylates / Polyacrylic acids Coatings >> Waterborne Water in excess of 100°C. Use of DISPEX A40 should be limited to pH 5-10.5 and temperatures lower than 70°C due to potential loss of volatile ammonia. Compared with inorganic dispersing agents, e.g. polyphosphate products, the organic polymer based DISPEX N40 and DISPEX A40 provide improved storage stability of both, the pigment dispersion and the formulated paint. There is little or no adverse reaction to high temperatures or pH changes as indicated in the graphs below, which are examples showing the accelerated effects. Preparation of the ready-for-use DISPEX R50 formulation Dilute DISPEX R50 to a 10% active substance solution by adding water. Then carefully add the selected alkali with constant stirring to achieve a pH of 7.5 - 8.5. It is natural that some heat is generated during this procedure. Incorporation of DISPEX N40, DISPEX A40 or DISPEX R50 formulation It is recommended to add the pigment to heavily stirred water containing the dispersing agent as opposed to addition of the dispersing agent to a pigment slurry. In general, the pH of the final preparation should be in the region of 8.5 to obtain optimum dispersing efficiency. The optimum amount of dispersing agent required to form a stable dispersion strongly depends on the pigment’s chemical nature, the particle surface and shape. The polymer base of the latex also plays a very important part in the stability equation. In general, significant overdosing may deteriorate the coatings properties (e.g. water resistance) and also generates an economic disadvantage. Likewise insufficient dispersing agent will lead to instability on storage. In common with other dispersing agents, because of the batch-to-batch variations of the demands of a specific pigment or latex type it is recommended that the formulator uses 1.5 - 2.0 times the determined optimum level of the dispersing agent. Ciba holds a database with information on recommended dosage levels for a variety of commonly used pigments in selected latex preparations. A more detailed explanation of dispersing agent evaluation is contained in the “Rheology Performance Brochure” which is also available from Ciba. Dispersing agents for a wide range of water-borne coatings. Can be used as supplied. The neutralising alkali used in conjunction with the acrylic polymer can significantly impact the properties of the final coating. Releases ammonia during the drying process and therefore has little impact on water and alkaline resistance of the dry film. Should be limited to pH 5-10.5 and temperatures lower than 70°C due to potential loss of volatile ammonia. Compared with inorganic dispersing agents, e.g. polyphosphate products, provides improved storage stability of both, the pigment dispersion and the formulated paint. There is little or no adverse reaction to high temperatures or pH changes. Recommended usage level: 0.5-2.0% based on total pigment weight. Add the pigment to heavily stirred water containing the dispersing agent as opposed to addition of the dispersing agent to a pigment slurry. In general, the pH of the final preparation should be in the region of 8.5 to obtain optimum dispersing efficiency.