Wacker Chemical Corporation

Tile grouts are applied between tiles to form a uniform surface and to protect the substrate from environmental exposure. Three main types of grouting materials exist: cement, epoxy or high performance polymeric, and ready-to-use (RTU). Each has its own respective strengths and deficiencies. RTU, or pre-mixed grouts, are formulated similarly to highly filled, water-based architectural coatings. As such, RTU grouts are relatively easy to apply and clean-up. While RTU grouts may not offer the high degree of water-protection and stain repellency of high performance polymer grouts, RTU grouts perform much better than cement grouts with respect to these properties. This reduction in performance compared to epoxy grouts is mitigated by the much lower cost and ease of use, as compared to epoxy grouts. This paper will investigate the major formulation parameters and their effect upon the final performance of RTU grout. The main focus of this work is to give chemists information which will allow them to formulate better RTU grouts. The main properties investigated were tensile (modulus, UTS and elongation), shear (lap-shear testing for adhesion), water permeability, stain repellency, and ease of application/clean-up—properties important for all grouts. A Taguchi Method DOE was set up to investigate the raw materials effect upon performance. The raw materials include: calcium carbonate fillers with a range of particle size and oil-absorption values, two acrylic polymers (Tg ~ 13 and 32°C), and two polyethylene fibers (lengths – 3 and 6 mm). These raw materials were chosen after evaluating commercially available grouts and finding these to be some of the key raw materials used.
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