Patent GB-1527870-A (GB)
Title: Device for emitting vapours of active substance
IPC: A01M1/20
Filed: 1975-11-27
Abstract: 1527870 Electrical device emitting insecticidal vapours; organophosphorus compounds and pyrethrinoids CIBA-GEIGY AG 27 Nov 1975 [27 Nov 1974] 48832/75 Headings A5E and A5G Devices intended to emit active vapours emitted by an active insecticidal substance comprises in a rigid assembly (a) a reservoir intended to contain the active substance and, having an evaporation surface for the emission of the active vapours, (b) an electrical resistance 6 associated with the reservoir 1 and 2 to heat at least the part thereof which comprises, or is close to, the evaporation surface, and (c) a system 10 for connecting the resistance to a source of electric current, wherein the reservoir comprise (i) a system of two plates 1 and 2 of a porous or fibrous material, one of the large faces of one of the plates facing one of the large faces of the other, and a frame for the plates, which separates the space between the two plates from the exterior, whilst leaving entirely or partially free at least one of the two large external faces of the two plates, which can thus serve as an evaporation surface, and (ii) an insecticidal organo-phosphorus substance having a vapour pressure, at 25‹C, of from 5 x 10<SP>-5</SP> to 5 x 10<SP>-3</SP> mbar, with or without addition of a pyrethrinoid insecticidal compound having a vapour pressure, at 25‹C, of from 1 x 10<SP>-6</SP> to 2 x 10<SP>-4</SP> mbar, with which the two plates are impregnated, the total evaporation surface of the two plates being at least 20 cm<SP>2</SP>, the amount of active substance being sufficient to give effective evaporation, at 85‹C, for a period of at least 10 hours, the thickness of the plates being sufficient to absorb the amount of active substance, and the resistance being enclosed within the system and so constructed as to heat the large internal faces of the two plates to a temperature of maximally 85‹C. The case consists of two halves 3 and 4 joined by a circular weld 5 and provided with perforated faces 11 and 12, the perforations being in the form of windows. Mica insulating plates 7, 8 and 9 are provided as shown in Fig. 2. Insecticidal compositions comprise an insecticidal organo-phosphorus substance having a vapour pressure at 25‹C, of from 5 x 10<SP>-5</SP> to 5 x 10<SP>-3</SP>mbar with or without addition of a pyrethrinoid insecticidal substance having a vapour pressure, at 25‹C, of from 1 x 10<SP>-6</SP> to 1.5 x 10<SP>-4</SP>mbar and optionally an adjuvant chosen from diluents, thickeners, stabiliser, perfumes, synergistic agents and dyestuffs. The diluent may be selected from the diesters formed from alkanols and dicarboxylic hydrocarbons, the diesters formed from alkyl-substituted or unsubstituted phenols and dicarboxylic hydrocarbons, the diesters formed from alkyl-substituted or unsubstituted cycloalkanols and dicarboxylic hydrocarbons, the diesters formed from phenyl alkanols and dicarboxylic hydrocarbons, the diesters formed from alkanediols and monocarboxylic hydrocarbons, the triesters formed from alkyl substituted or unsubstituted phenols and phosphoric acid, the triesters formed from alkanols and phosphoric acid, the polyalkylene glycols, the fatty alcohols, the fatty acids, C 18  + alkanes, C 18  + alkanones, C 18  + alkenones, chlorinated biphenyls, chlorinated terphenyls and the non- volatile halogenoalkanes. The stabiliser may be selected from epoxidised compounds, azo compounds and metal complex azo compounds, benzodioxides, phenolic compounds, carboxylic acid anhydrides, sulphur, compounds containing at least one divalent sulphur atom and aromatic amines. The thickener may be selected from metal salts of a fatty acid, amine salts of a fatty acid and modified montmorillonites.