Sag-resistance for tile cements - additive based on polyacryl amide Long-chain organic polymers having a Flocculation Index of less than 0.5 are described as thickening agents for cementitious systems: Polyacrylamides, starch ethers, sodium CMC, polyethylen oxides. (Includes the description of a "Flocculation Index Test Method" for organic polymers.) Publisher: Tile Council of America Inc., 1977, US4021257 Cat: Patents: Polyacryl amide-based thickeners