Gypsum plaster
AssigneeManufacture de Produits Chimiques Protex
InventorChristian M. Joseph
Life of this patent
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Abstract
Gypsum and anhydrite plaster is improved by adding at least one alkylene diphosphonic acid or water soluble salt thereof, represented by the following formula: ##STR1## wherein X is hydrogen or lower alkyl of 1-4 carbons, Y is hydrogen, hydroxy or lower alkyl of 1-4 carbons, and n is 1-10. The plaster is found to have an increased finishing time, while the quantity of water necessary is reduced and the mechanical strength of the finished plaster is improved.
Claims7
A gypsum or anhydrite plaster composition, comprising said plaster and a small quantity sufficient to increase finishing time while reducing the quantity of water necessary and increasing mechanical strength, of an additive of at least one alkylene diphosphonic acid, or water soluble salt thereof, represented by the following general formula:
- ##STR11## wherein X is a hydrogen atom or a lower alkyl group containing from 1 to 4 carbon atoms, Y is a hydrogen atom, a hydroxy radical or a lower alkyl group containing from 1 to 4 carbon atoms and n is a whole number between 1 and 10, inclusive.
Process of preparing and using compositions of gypsum plaster or plaster base mixtures, comprising either premixing dry with the plaster when it is in powder form, or adding to the plaster mixing water when it is in liquid form,
- an additive composition comprising at least one alkylene diphosphonic acid, or water soluble salt thereof, represented by the formula:
- ##STR12## wherein X is a hydrogen atom or a lower alkyl group containing from 1 to 4 carbon atoms, Y is a hydrogen atom, a hydroxy radical or a lower alkyl group containing from 1 to 4 carbon atoms and n is a whole number between 1 and 10, inclusive,
- with a content of said additive composition ranging between 0.001 and 2 parts per hundred, the content expressed in dry material in relation to the plaster.
Dependencies are inferred from the claim text.