Improvements in or relating to plaster bandages

A plaster composition, primarily for use in a plaster of Paris bandage, comprises plaster of Paris intimately mixed with between 0.1 and 10% of hydroxide of an alkali metal, or an oxide or hydroxide of an alkaline earth metal, and between 0.1 and 10% of a finely divided water-repellent organopolysiloxane. Suitable organopolysiloxanes include those in which the organo group may be an alkyl group, such as methyl or ethyl, an aryl group, such as phenyl, or an unsaturated group such as vinyl or allyl. Those with methyl groups are normally preferred. The constituents may be mixed dry but it is also proposed to form a slurry of the metal hydroxide and poly-siloxane with unburnt gypsum and subsequently to heat it to a temperature sufficiently high to convert the gypsum to plaster of Paris.ALSO:A plaster bandage comprises plaster of Paris intimately mixed with between 0.1 and 10% of hydroxide of an alkali metal, or an oxide or hydroxide of an alkaline earth metal, and between 0.1 and 10% of a finely divided water-repellent solid organopolysiloxane. Suitable organopolysiloxanes include those in which the organo group may be an alkyl group, such as methyl or ethyl, an aryl group, such as phenyl, or an unsaturated group such as vinyl or allyl. Those with methyl groups are normally preferred. The dry constituents, after mixing, may be applied directly to a gauze backing or a slurry may be formed for application to the gauze, but if water is used to form the slurry the application and drying are carried out at above 95 DEG C. to prevent the plaster of Paris setting. It is also proposed, however, to form a slurry of the metal hydroxide and polysiloxane with unburnt gypsum and after this has been applied to the gauze to heat it to a temperature sufficiently high to convert the gypsum to plaster of Paris.