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ACRYSOL™ RM-8W Rheology Modifier - dow.com

ACRYSOL™ RM-8W Rheology Modifier Description ACRYSOL RM-8W is a nonionic urethane rheology modifier, designed to formulate high performance, environmentally ...

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Text of ACRYSOL™ RM-8W Rheology Modifier - dow.com

ACRYSOL RM-8W Rheology Modifier Description ACRYSOL RM-8W is a nonionic urethane rheology modifier, designed to formulate high performance, environmentally friendly, low VOC solvent-free interior/exterior paints. ACRYSOL RM-8W has a pseudoplastic rheology profile, similar to the ones of ACRYSOL RM-8 and ACRYSOL RM-825 but is delivered free of solvents. ACRYSOL RM-8W allows the formulation of paints with an excellent balance between flow and sag. ACRYSOL RM-8W can be used as a cothickener in many types of formulations for attaining a desired balance of low and high shear viscosities. ACRYSOL RM-8W has excellent compatibility at all blend ratios with the more Newtonian, solvent-free rheology modifier ACRYSOL RM-2020. The combination of the two, gives a wider formulation latitude to the paint formulator than previously attainable for solvent-free systems. ACRYSOL RM-8W is delivered as a low viscosity liquid and is therefore very easy to incorporate and should improve the paint manufacturing process. Characteristics of the Product zSolvent-free zLow odor zResistant to microbial attack zExcellent water and alkali resistance zExcellent spatter resistance zUse over a wide pH range zEase of handling Formulations Guidelines ACRYSOL RM-8W rheology modifier is supplied as a pourable and pumpable liquid, free of solvent and with very low odor. It can be added to the mill-base or to the letdown portion of the formulation. ACRYSOL RM-8W should not be preblended with other rheology modifiers prior to paint addition but should be added separately. Rheology Profile ACRYSOL RM-8W has a pseudoplastic rheology profile, similar to the ones of ACRYSOL RM-8 and ACRYSOL RM-825, but is delivered free of solvents. ACRYSOL RM-8W rheology modifier shows a very good balance of low and high shear viscosity, which allows to formulate paints with outstanding flow and sag resistance. Typical Properties These properties are typical but do not constitute specifications. Appearance Hazy liquid Active solids content % * Brookfield viscosity <3500 cps Specific gravity (wet polymer) Solvent Water ChemistryHEUR***Total solids content is including solvent-free proprietary viscosity suppressant**Hydrophobically modified polyethylene oxide urethaneACRYSOL RM-8W can be used as a cothickener in many types of formulations for attaining a desired balance of low and high shear viscosities. It has excellent compatibility at all blend ratios with the more Newtonian, solvent-free rheology modifier ACRYSOL RM-2020. The combination of the two gives a wider formulation latitude to the paint formulator than previously attainable for solvent-free systems. Dispersing Agents Dispersing agents with low ionic content have proven to work well with ACRYSOL RM-8W. OROTAN 165, 681 and 731A ER are all very compatible and OROTAN 1124 can be recommended as well. For environmentally friendly, low odor paints, we recommend the ammonia and solvent-free OROTAN 731A ER. Depending on formulation type, usage levels of calculated on total powder have been found adequate. Dispersants which introduce a high level of electrolytes into the paint formulation, such as polyacid homopolymers, should be avoided, as they may cause syneresis. Surfactants, Wetting Agents, and Cosolvents See below under Interactive effects of the Paint System. Paint pH Control Being nonionic, ACRYSOL RM-8W is usable over a wide pH range and in most formulations pH is not a critical factor. For most latex paints formulated with ACRYSOL RM-8W, a pH between will give best stability and rheology control. Thickener Combinations ACRYSOL RM-8W can be combined with other rheology modifiers to tailor the viscosity profile of the paint. Combinations with ACRYSOL RM-2020 for increased high shear viscosity and ACRYSOL RM-12W for increased low shear viscosity have proven to be very successful in this respect. ACRYSOL RM-8W should not be preblended with other rheology modifiers prior to paint addition. Interactive Effects of the Paint System The rheology modifying mechanism of ACRYSOL RM-8W is primarily associative. Hydrophobic elements of the molecular structure tend to associate with other hydrophobic elements in the paint. These other hydrophobic elements are mostly latex binder and opaque polymers. Association with anorganic pigments is less frequent, but can exist. In the end, we get a network of associations, modifying the rheological profile of the paint and giving it the desired flow. However, associative also means that the rheology of the paint is influenced by a whole range of elements other than the thickener itself. The following factors have a direct impact on the efficiency of ACRYSOL RM-8W in latex paints: zLatex polymer particle size and distribution zLatex polymer composition and stabilization zSurfactants and cosolvents Latex Polymer Particle Size and Distribution The primary site for the associative characteristics of a rheology modifier is the surface of the binder particles. As a consequence, a greater surface area will lead to stronger association. Greater association leads to an increased efficiency. For a given volume of unimodal latex binder, a small particle size binder will have a greater total surface area than a larger particle size binder. Thus, the rheology modifier will work more efficiently with the smaller particle size binder. When a binder contains a distribution of particle sizes, the answer is not as clear. Here the distribution of particle sizes from large to small will determine the associative conditions more realistically than average particle size. Latex Polymer Composition ACRYSOL RM-8W is most efficient with hydrophobic latexes. This hydrophobicity may vary with the latex composition or the stabilizing system. Surfactants The hydrophobic nature of surfactants allows them to compete with the associative capacity of the rheology modifier for the latex polymer surfaces. If the surfactant is able to displace the rheology modifier, the viscosity that is inherent to the rheology modifier polymer interaction can be reduced considerably. This means that special attention is needed for the type and amount of surfactant that is used, and to the combination with the binder. In addition, consideration must be given to the surfactants introduced with the colorant system. Predispersed colorants generally contain surfactants for stability and to facilitate color acceptance. Each colorant may have a different type and level of surfactant. Cosolvents Water insoluble cosolvents, such as Texanol, have little or no effect on the medium shear viscosity of a paint thickened with an associative thickener. Water soluble cosolvents, however, may reduce the low shear viscosity. Products such as ethylene glycol and propylene glycol will have the least effect, while butyl Carbitol will have the greatest effect among the cosolvents tested to date. As in the case of surfactants, the level of cosolvent that is introduced with a predispersed colorant must be accounted for. One outcome of this cosolvent interaction is the potential to use these products for low shear viscosity adjustments. This can be done very effectively, but with a cost penalty and a potential reduction in water resistance due to the water solubility of these products. Unique Technology Although the thickener is purely nonionic by nature, this technology accounts for the fact that in many ways ACRYSOL RM-8W does not behave in the exact same manner as its predecessor (ACRYSOL RM-8). This is particularly true about its interactions with surfactants and cosolvents (in case they are used). With most urethane thickeners, addition of surfactants leads to lesser efficiency. In the case of ACRYSOL RM-8W, quite the opposite can occur. Up to a certain point, addition of surfactants may increase the thickening efficiency, until a certain maximum is reached, after which the product behaves like a traditional urethane rheology modifier and efficiency starts to drop. Therefore, if increased efficiency is required, testing addition of surfactants is recommended, in particular when the binder system is stabilized by colloids. In these situations Triton X-100, Triton X-405 and Rhodafac RS-410 and Rhodafac RS-610 have proved to be very effective. Safe Handling Information The Dow Chemical Company Material Safety Data Sheets (MSDS) contain pertinent information that you may need to protect your employees and customers against any known health or safety hazards associated with our products. Under the OSHA Hazard Communication Standard, workers must have access to and understand MSDS on all hazardous substances to which they are exposed. Thus, it is important that you provide appropriate training and information to your employees and make sure they have available to them MSDS on any hazardous products in their workplace. The Dow Chemical Company sends MSDS on non-OSHA-hazardous as well as OSHA-hazardous products to its customers upon initial shipment, including samples. If you do not have access to one of these MSDS, please contact your local Dow representative for a copy. Updated MSDS are sent upon revision to all customers of record. In addition, MSDS are sent annually to all customers receiving products deemed hazardous under the Superfund Amendments and Reauthorization Act. MSDS should be obtained from suppliers of other materials recommended in this bulletin. The Dow Chemical Company is a member of the American Chemistry Council and is committed to ACC s Responsible Care Program. ACRYSOL is a trademark of The Dow Chemical Company. These suggestions and data are based on information we believe to be reliable. They are offered in good faith, but without guarantee, as conditions and methods of use of our products are beyond our control. We recommend that the prospective user determine the suitability of our materials and suggestions before adopting them on a commercial scale. Suggestions for uses of our products or the inclusion of descriptive material from patents and the citation of specific patents in this publication should not be understood as recommending the use of our products in violation of any patent or as permission or license to use any patents of The Dow Chemical Company. 2007-2009 Rohm and Haas is a wholly owned subsidiary of The Dow Chemical Company. All rights 2007

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