A process of manufacturing thickeners and the use of thus produced thickeners in high-viscosity unsaturated polyester containing formulations

The invention relates to the use of at least one mixed mineral organoclay rheology additive, which comprises or consists of a quaternary alkyl-ammonium salt treated mineral clay mixture prepared by forming an aqueous hormite clay slurry (a), forming an aqueous smectite clay slurry (b), combining the aqueous hormite clay slurry (a) with the aqueous smectite clay slurry (b) to form a combined clay slurry (c), treating the combined clay slurry (c) with one or more quaternary alkyl-ammonium salts, separating the thus produced quaternary alkyl-ammonium salt treated mineral clay mixture from the aqueous medium, in which the aqueous hormite clay slurry (a) being formed by (i.1) dispersing a fraction of one or more hormite clays selected from the group of sepiolites and palygorskites in an aqueous medium to form a dispersion, and the aqueous smectite clay slurry (b) being formed by (ii.1) dispersing a fraction of one or more smectite clays in an aqueous medium to form a dispersion, and in that the weight of the hormite clay content exceeds the weight of the smectite clay content in the combined clay slurry (c); and subjecting the dispersions formed in (i.1) and (ii.1) to high speed fluid shear before carrying out step iii. and/or after having carried out step iii; and wherein the one or more hormite clays employed in the formation of the aqueous hormite clay slurry (a) exhibit a methylene blue exchange capacity below 20 mmol methylene blue per 100 g of the one or more hormite clays in dry state, the methylene blue exchange capacity being determined on the part of an aqueous hormite clay slurry that passes a 100 mesh U.S. standard screen, and the hormite clay slurry before passing the 100 mesh U.S. standard screen having a particle size distribution such that at least 90 % by weight of the hormite clay contained in the aqueous hormite clay slurry passes the 100 mesh U.S. standard screen, in a liquid composition comprising at least one unsaturated polyester. The invention also relates to a process for producing a mixed mineral organoclay rheology additive and the use of the thus produced additive as a thickening agent in liquid compositions.