READY MADE CEMENTITIOUS COMPOSITION

摘要

(57) Abstract The invention provides ready mixed composition comprising: calcium sulphate hemihydrate; water; and a retarder comprising one of the following: (1) a polymer or a copolymer of a monomer of formula (I) (2) a modified maleic anhydride polymer or copolymer. (3) a polymer or copolymer of a monomer having formula (II) wherein R is C4H9 or (CH3) 2CH. (4) 0.09 to 0.1 % by weight plaster of a polymer or copolymer of a monomer having formula (III) and having a molecular weight in the range of about 110 000 to about 140 000. The invention provides ready mixed gypsum plaster jointing compounds with long shelf lives which can be induced to set by the addition of an accelerator. The invention also provides a ready mixed coating system comprising a gypsum composition as described above and a setting accelerator which when mixed with the cementitious composition induces the cementitious composition to set.