GB379892A - A process for the production of foams - Google Patents

Abstract

A process for the production of foams consists in bringing together at the place of application of the foam components of salve-like consistency containing respectively a substance capable of evolving a gas and a substance which will cause the evolution. The material to which the salve-like consistency is due may be tragacanth or the like. The gas-producing components may be, for example, a salt such as sodium bicarbonate and an acid such as tartaric acid or an acid salt such as aluminium acetate for producing carbon dioxide, sodium sulphide and tartaric acid for producing sulphuretted hydrogen, sodium nitrite and tartaric acid for producing nitric oxide, sodium nitrite and hydroxylamine hydrochloride for producing nitrous oxide, calcium hydroxide and ammonium chloride for producing ammonia. Oxygen or sulphur dioxide may be produced together with carbon dioxide by suitable additions, for instance pyrolusite and the material known under the registered Trade Mark "Perhydrol" to produce oxygen and an addition of sodium bisulphite to produce sulphur dioxide. The salves should contain sufficient water for the necessary reaction to occur. Strong acids or pure alkali carbonates are unsuitable as components as they disintegrate the salve and have injurious effects on the body. A mixture of sodium carbonate and bicarbonate is however suitable. As alkali carbonates tend to make the salves viscous agar may be added to prevent this effect. The foams are useful for exterminating pests on the bark or in the wood of trees by means of the evolved gas or an added active substance, or for heating wounds or body cavities in medicinal and veterinary practice. A preparation for exterminating tree pests consists of the components: A, a salve comprising tragacanth in glycerine and water into which sodium carbonate and bicarbonate are stirred, and B, a salve having the same base as A mixed with tartaric acid or aluminium acetate and nicotine sulphate. Instead of the alkali carbonate and bicarbonate liver of sulphur may be used. For use as a medicine a component such as A is used with a component similar to B but with iodoform or bismuth subgallate substituted for the nicotine. Emulsions of fatty, oily and like substances may be used alone or in association with tragacanth albumen, starch, saponin, gums, &c. as the basis of the salves. Devices for bringing the components together may consist of rigid containers arranged side by side with a duplex piston or of collapsable tubes having compartments side by side, one within the other or centrally divided and discharged simultaneously by pressing the bottom of the compartments by a suitable key device. In the case of containers having separate openings a bifurcated inset tube is used to direct the two components to the place of application.