Patent ID: 7455728
Filing Date: 2008-11-25
Classification: C04B

Abstract:
1. A method for retarding plaster setting and plaster preparations, comprising admixing with said plaster or said plaster preparations the following composition: a) tartaric acid in an amount of at least 0.01 to 1.0 weight % relative to the plaster amount; b) sodium trimetaphosphate in an amount of 0.05 to 0.5 weight %, relative to the plaster amount; and c) 0 to at least 0.01 weight % , relative to said plaster or said plaster preparations, sodium polyphosphate with an average chain length of at least 4 to 50 phosphate units; which is further characterized in that the components b) said sodium trimetaphosphate and/or c) sodium polyphosphate are mixed together in the dry state and are added to the plaster to be retarded in the form of a fine-particle powder, having a particle size distribution for which at least 95% of the components are smaller than 200μm.