Properties / Applications: Bayhydrol A 2470 is a hydroxyfunctional polyacrylic dispersion which can be thinned with water to application viscosity. The viscosity of the product is largely governed by the pH. As the pH may decrease during storage, a decrease in viscosity is also to be expected. The viscosity can be restored to its original value by the addition of small amounts of an aqueous 10% solution of dimethyl ethanol amine. Bayhydrol A 2470 combined with aliphatic polyisocyanates yields high-gloss top coats which can be dried at room temperature or force-dried, e.g. at 80°C. The cured paint films are hard and flexible with outstanding resistance to solvents and water and excellent weatherability. Application of a clearcoat based on Bayhydrol A 2470 directly on wood may lead to discoloration. When properly formulated, e.g. in combination with Bayhydur 304 in an NCO / OH ratio of 1.5 : 1, the pot life is approximately 4 hours. Bayhydrol A 2470 has good pigment wetting properties and high shear stability. Bead mills have proved suitable as grinding equipment. Only pigments and extenders with a minimum water-soluble content should be used. Given the many pigments and extenders available, compatibility testing should always be carried out. When mixing Bayhydur or Desmodur into the mill base, a thickener must be added to ensure a high shear effect. The addition of approximately 0.4% Borchigen® PW 25 (calculated on the solid binder) has proved suitable for formulations based on Bayhydrol A 2470. Levelling and substrate wetting can be optimised by adding, for example Byk® 380. Byk® 011 has proved to be a suitable antifoam. Application and formulation equipment can be cleaned with water, alkaline cleaning agents or isopropanol. As with any product, use of Bayhydrol A 2470 in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability.

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