GB621732A - Improvements in or relating to the dispersion or dissemination of insecticides, fungicides, weed-killers and the like - Google Patents

Abstract

621,732. Insecticidal fumigants. BATEMAN, E. W., and FLETCHER, W. Jan. 8, 1945, No. 689. [Class 81(i)] [Also in Group XXI] An ignitable composition, adapted to evolte on burning under confined conditions a gas incorporating a vapour of a pest - controlling substance, comprises in admixutre a heat sensitive vaporizable pest-controlling substance, a solid combustible organic compound and a highly oxygenated inorganic compound capable of promoting combustion, these components being pesent in such proportions and the organic and inorganic compounds having such a nature that the calorimetric value of the ignitable composition is not substantially greater than 320 calories/gram. and the composition burns at a rate adequate to ensure that a high proportion of the pest-controlling substance is vaporised without being decomposed. Suitable pestcontrolling substances are D.D.T. and benzene hexachloride including the gamma isomer. Suitable stabilizers (for the pestcontrolling substance) which may be incorporated are urea, diphenylamine or a metal oxide or carbonate, e.g. magnesium or zinc oxide. The self combustible composition which may comprise from 35 to 50 per cent of the ignitable composition may comprise an inorganic oxidizing agent, e.g., a chlorate or a perchlorate such as potassium chlorate, together with an excess of an organic fuel, e.g., lactose, sucrose, glucose, mannitol or sorbitol. Thiourea may also be employed in admixture with other fuels. The ignitable composition may also include an absorbent material such as kieselguhr. A suitable container for igniting the composition has a relatively small discharge orifice or orifices spaced from the composition. In one embodiment the composition is contained in an inner body portion 2 having a perforated wall 6 and co-axially arranged within a container 1 to form an annular space 3 there between. A closure 11 of the container is provided with orifices 20, which may be sealed with waterproof adhesive tape or shellacked paper, and an inner cylindrical part adapted to fit into a recess 10 of a lid 8 of the inner body portion 2 and form a socket to receive an ignition device. In another form suitable as a projectile, the charge in the container is in the form of a tube arranged to burn from the bore and discharge gas through a perforated baffle into a central conduit of the container from which the gas escapes at the end or ends thereof. The composition may be ignited by means of cap, a pull-wire friction device or match composition, or where intended to be ejected, the flash of the propellant may be employed. The container may be of compressed paper, moulded composition or metal. According to the Provisional Specification the self combustible composition may be a propellant such as a smokeless powder or N.C.Y. propellant powder or it may contain a nitrate as the inorganic oxidizing agent. Dinitro-o-creosol is disclosed as a suitable weed killer.