Patent GB-1033015-A (GB)
Title: Improvements in or relating to the prevention of microbial growth
IPC: C10M173/00
Filed: 1963-02-06
Abstract: An anti-microbial aqueous emulsion of suspension of a mineral lubricating oil comprises a source of halogen ions capable of giving a concentration of 1 to 50 p.p.m. by weight of halogen in said emulsion or suspension, and an oxidizing agent.  The preferred halogen is iodine and sources specified are the iodides, iodates and periodates of sodium, K, Al and Zn are used and elemental iodine crystals may be used in the emulsion as the growth inhibitor, by passage of a slow stream of water through the crystals and thereafter passing the iodine solution into the emulsion.  The pH of the emulsions may be between 3 and 9.6.  The appropriate pH is obtained by addition of citric and/or phosphoric acid and buffers, or addition of NaOH and Na3PO4. Oxidizing agents specified are soluble permanganates, hypochlorites, chlorates, perchlorates, ferric salts, chromates, dichromates, cerates, persulphates, nitrites, periodates, iodates, are used in the emulsion in a pH range 5.5-6.5. In further embodiments of the invention, organic iodine compounds such as polyvinylpyrrolidone and pyridine complexes of iodine, organic alkyl and aryl iodine-containing compounds of the iodo, iodoso and iodoxy types; and inorganic chlorine and bromine compounds of types equivalent to the inorganic iodine compounds previously mentioned, also organic chlorine or bromine compounds, e.g. acetylcholine Br, acetyl choline Cl and a basin can be used in the acid medium, pH range 5.5-6.5. All these above-mentioned compounds plus the inorganic iodine compounds can also be used in alkaline emulsion medium (7-9.6), in which case alternative oxidizing agents operative in this range are used.  For example, iodate ions supported by NiSO4, ZnSO4, boric acid and mannitol, chromic sulphate, Fe2(SO4)3 as catalysts. Two examples are given of typical soluble oil emulsions according to the invention.ALSO:An aqueous organic emulsion or suspension comprises a source of halogen ions capable of giving a concentration of 1 to 50 p.p.m. by weight of halogen in said emulsion or suspension, and an oxidizing agent, present in sufficient quantity to oxidize to elemental halogen, any halogen ions produced by the reduction of elemental halogen by micro-organisms present in said emulsion or suspension.  Inhibition of microbial growth in industrial organic emulsions or suspensions such as latex emulsions, starch pastes and urethane foam emulsions is referred to.  In the preferred embodiment of the invention, water-soluble inorganic iodine compounds are employed in an emulsion having a pH of 5.5-6.5. Such compounds as the iodides, iodates and periodates of sodium, K, Al and Zn are used and elemental iodine crystals may be used in the emulsion as the growth inhibitor, by passage of a slow stream of water through the crystals and thereafter passing the iodine solution into the emulsion. The pH of all of the emulsions of the invention may be between 3 and 9.6, but are preferably between 5.5 to 6.5.  The appropriate pH is obtained by addition of citric and/or phosphoric acid and buffers, or addition of NaOH and Na3PO4.  An oxidizing agent is employed in the emulsion to re-oxidize the iodine ions formed as a result of the destruction of micro-organisms. Such oxidizing agents as water-soluble permanganates, hypochlorites, chlorates, perchlorates, ferric salts, chromates, dichromates, cerates, persulphates, nitrites, periodates, iodates, are used in the emulsion in a pH range 5.5-6.5.  In further embodiments of the invention, organic iodine compounds such as polyvinylpyrrolidone and pyridine complexes of iodine, organic alkyl and aryl iodine-containing compounds of the iodo, iodoso and iodoxy types; and inorganic chlorine and bromine compounds of types equivalent to the inorganic iodine compounds previously mentioned, also organic chlorine or bromine compounds, e.g. acetyl-chlorine Br, acetyl choline Cl and acetyl carbromal can be used in the acid medium, pH range 5.5-6.5. All these above-mentioned compounds plus the inorganic iodine compounds can also be used in alkaline emulsion medium (7-9.6), in which case alternative oxidizing agents operative in this range are used; for example, iodate ions supported by NiSO4, ZnSO4, boric acid and mannitol, chromic sulphate, Fe2(SO4)3 as catalysts.ALSO:An aqueous organic emulsion or suspension comprises a source of halogen ions capable of giving a concentration of 1 to 50 p. p. m. by weight of halogen in said emulsion or suspension, and oxidising agent, present in sufficient quantity to oxidize to elemental halogen, any halogen ions produced by the reduction of elemental halogen by micro-organisms present in said emulsion or suspension. Inhibition of microbialgrowth in other industrial organic emulsions or suspension such as latex emulsions, urethane foam emulsions paste suspensions such as starch paste, and wood pulp emulsions can be achieved by the method of the present invention. In the preferred embodiment of the invention water soluble inorganic iodine compounds are employed in an emulsion having a pH of 5.5-6.5.  Such compounds as the iodides, iodates and periodates of sodium, K, Al and Zn are used and elemental iodine crystals may be used in the emulsion as the growth inhibitor, by passage of a slow stream of water through the crystals and thereafter passing the iodine solution into the emulsion.  The pH of all of the emulsions of the invention may be between 3 and 9.6 but are preferably between 5.5 to 6.5.  The appropriate pH is obtained by addition of citric and/or phosphoric acid and buffers, or addition of NaOH and Na3PO4.  An oxidising agent is employed in the emulsion to reoxidise the iodine ions formed as a result of the destruction of micro-organisms.  Such oxidising agents as water soluble permaganates, hypochlorites, chlorates, perchlorates, ferric salts chromates, dichromates, cerates, persulphates, nitrites, periodates, iodates, are used in the emulsion in a pH range 5.5-6.5.  In further embodiments of the invention, organic iodine compounds such as polyvinylpyrrolidone and pyridine complexes of iodine, organic alkyl and aryl iodine-containing compounds of the iodo, iodoso and iodoxy types: and inorganic chlorine and bromine compounds of types equivalent to the inorganic iodine compounds previously mentioned, also organic chlorine or bromine compounds e.g. acetyl-choline Br, acetyl choline C1 and acetyle carbromal can be used in the acid medium, pH range 5.5-6.5.  All these above mentioned compounds plus the inorganic iodine compounds can also be used in alkaline emulsion medium (7-9.6), in which case alternative oxidising agents operative in this range are used.  For example, iodate ions supported by NiSO4, ZnSO4, boric acid and mannitol, chromic sulphate, Fe2(SO4)3 as catalysts.  Two examples are given of typical soluble oil emulsions according to the invention.