GB895992A - Calcium silicate pesticidal carrier - Google Patents

Abstract

Diatomaceous calcium silicate, produced by reacting hydrated lime and diatomaceous earth as described in Specification 268,011, is reacted at 0 DEG -90 DEG C. in the presence of water with carbon dioxide until a carbonated diatomaceous calcium silicate is obtained which has a bulk density of 8,45 to 0,54 grams per cubic centimeter and which imparts a lower pH to an aqueous system than the diatomaceous calcium silicate before carbonation. The carbonated product is particularly suitable as a pesticide carrier. The carbon dioxide may be employed in gaseous, liquid or solid state; the reaction is preferably effected in the presence of 5-20% by weight of water based on the silicate reactant and continued until 7 to 25 parts by weight of carbon dioxide per 100 parts of silicate are taken up. Termination of carbonation is indicated by abatement of exothermic reaction heat.ALSO:A carbonated diatomaceous calcium silicate, employed as a carrier for pesticides, is prepared by reacting a diatomaceous calcium silicate (the reaction product of hydrated lime and diatomaceous earth) with carbon dioxide in the presence of water (see Group III). The carbonated silicate, which imparts a lower pH to an aqueous solution than the initial silicate reactant, is particularly suitable for base-sensitive pesticides. A typical dry, wettable powder formulation consists of 47 to 87 parts of the carrier, 15-50 parts of the pesticide, 2 parts of a dispersing agent such as a naphthalene sulphonic acid-formaldehyde condensate and 1 part of a wetting agent such as an alkylphenoxypolyethoxyethanol. Specific formulations referred to comprise 72 parts of the carrier, 2 parts of the sodium salt of a copolymer of maleic anhydride and diisobutylene, 1 part of octylphenoxypolyethoxyethanol and 25 parts of either 1,1-bis-(chlorophenyl) - 2,2,2 - trichloroethanol ("Kelthane," Registered Trade Mark), dinitro - (1 - methylheptyl) - phenyl crotonate ("Karathane," Registered Trade Mark), or o,o - dimethyl - 5 - (1,2 - dicarbethoxyethyl) - dithiophosphate ("Malathion," Registered Trade Mark). Further insecticides referred to are octachloro - 4,7 methane tetrahydroindain ("Chlordane," Registered Trade Mark), D.D.T., hexachlorocyclohexane (Lindane), chlorinated camphene (Toxaphene), chloroethyl-methyl (p-tert-butylphenoxy) ethyl sulphite ("Aramite," Registered Trade Mark), ethyl 2-hydroxy-2,2-bis - (4 - chlorophenyl) - acetate (Chlorobenzilate), dichloro - 2,2 - bis - (p - chlorophenyl) - ethane ("Rhothane," Registered Trade Mark), and dichloro - 2,2 - bis - (p - ethylphenyl) ethane ("Perthane," Registered Trade Mark), and dichloro - 2,2 - bis - (p - ethylphenyl) ethane ("Perthane," Registered Trade Mark), and trichloro - 2,2 - bis - (p - methoxy phenyl) ethane (Methoxychlor). Specification 268,011 is referred to.