GB719360A - Insecticidal preparations - Google Patents

Abstract

A pourable insecticidal preparation comprises (a) 10 to 75 per cent by weight of a finely divided solid material including one or more insecticides and one or more filter materials capable of absorbing at least 60 per cent of water, by weight of the dry filler, (b) 10 to 50 per cent by weight of a water-immiscible liquid having a viscosity below about 3000 centipoises at 20 DEG C, which does not solidify above 20 DEG C and which substantially does not include components boiling below 50 DEG C, (c) 0.25 to 25 per cent by weight of one or more emulsifying agents, and (d) 10 to 40 per cent by weight of water, the particle size of the solid components being below about 100 microns and not more than about 30 per cent by weight of said solid components being dissolved in the water-immiscible liquid. Specified filters, which preferably comprise 0.5 to 10 per cent of the insecticide, are silica gels, magnesium oxide and clays such as pyrophyllite, kaolinite, talc, Fullers earth and bentonite, stability is improved by the addition of resins (0.3 to 2 per cent of the preparation), e.g. synthetic resins such as coumarone and indene resins, phenol-formaldehyde resins, and natural resins. Specified insecticides are naphthalene, p-dichlorobenzene, benzene hexachloride, D.D.T., and D.D.T. type containing fluorine or methoxy substituents, metaldehyde, aldrin, dieldrin, rotenone, tetraphenyl tin, lead arsenate, calcium arsenate; chloroethyl-b (p-tertiary butyl phenoxy) a-methyl ethyl sulphite; bis (p-chlorophenoxy) methane and 1.1 bis (p-chlorophenyl) ethanol; dinitro-o-ocresol and thiocyanates of sulphonic acids derived from polycyclic hydrocarbons such as pinene. Specified water-immiscible liquids are chlorinated diphenyl, tetrachloroethane and other halogenated hydrocarbons; alcohols, ketones, esters, ethers, amines and silicones; hydrocarbon mineral oils, e.g. spindle oil, kerosine and gas oil; and vegetable oils such as cottonseed oil, castor oil and animal oils, e.g. sperm. Specified emulsifiers are (a) non-ionic, e.g. ethers of alkyl phenols with polyethylene glycols and N-substituted long chain fatty acid amides, and (b) ionic, e.g. sodium salts of acid alkyl esters of sulphuric acid, sulphonates and oleates. The larger proportion of the emulsifier is of the non-ionic type. The solids may be ground with at least 25 per cent and preferably 45 to 70 per cent of liquid, preferably the water-immiscible liquid, the emulsifier dissolved in water or the water-immiscible liquid being incorporated before, during or after grinding. Alternatively, the insecticide may be recrystallized from the water-immiscible liquid by cooling the heated solution or by adding the whole or a part of the water content of the preparation in the form of ice, the preparation then being ground in a mill. The solids may have a particle size below 25 microns and even below 10 microns.