Patent GB-1006777-A (GB)
Title: Novel silicone-silicate polymers and their use in inhibiting the corrosion of metals
IPC: C08G77/00
Filed: 1961-11-29
Abstract: An organosiloxane-silicate polymer containing silicon-bonded groups of the formula M 1/a OOCR-, wherein R is a divalent hydrocarbon radical M is a cation that forms a watersoluble silicate and a is the valency of M (see Division C3), is used as a corrosion inhibitor in any aqueous liquid which comes into contact with metals, and particularly in anti-freeze and coolant compositions for use in cooling internal combustion engines.  Whereas the anti-freeze compositions are anhydrous or contain, in addition to the alcohol and inhibitor, a small amount of water, the coolant compositions contain large amounts of water. The inhibitor is usually used in amount of 0.1 to 10 pts. (by wt.) per 100 pts. of alcohol, e.g. methanol, ethanol, propanol, glycerol or ethylene, diethylene or triethylene glycol, and the compositions can contain from 0 to 900 pts. of water per 100 pts. of alcohol.  Anti-foam agents, identifying dyes, pH indicators, conventional inhibitors, sealants and anti-creep agents, may also be added.  The compositions can be made by merely mixing the ingredients together, or by forming the starting siloxane in situ from a suitable silane, e.g. by adding an anhydrous mixture of the silane, silicate and alcohol (which mixture can be stored per se) to the cooling water of a cooling system.  The compositions can also be used as heat-transfer media and hydraulic fluids.ALSO:The corrosion of metals below sodium in the electromotive series that come into contact with aqueous liquids is inhibited by adding to the liquid an inhibiting amount of a certain organosiloxane-silicate polymer (see Division C3) or a mixture of reactants capable of forming the inhibitor in situ.  The inhibitors are particularly suitable in aqueous alcohol solutions for use as anti-freeze or coolant compositions in internal combustion engine cooling systems composed of iron, brass, copper, aluminium or alloys thereof.  The inhibitor is usually used in amount of 0.1 - 10 parts (by weight) per 100 parts of the alcohol.ALSO:A polymer comprising (by weight per 100 parts of the polymer) from 0.1 to 99.9 parts of siloxane units of the formula <FORM:1006777/C3/1> and from 0.1 to 99.9 parts of units of the formula <FORM:1006777/C3/2> wherein M is an inorganic or organic cation that forms a water-soluble silicate, a is the valency of M, R is a divalent hydrocarbon radical containing 0 or 1 substituent [M 1/a OOC-] group, each [M 1/a OOC-] group is connected to Si through at least 2 C atoms of the R radical, R1 is a monovalent hydrocarbon radical, b is 1, 2 or 3, c is 0, 1 or 2, b+c is 1, 2 or 3 and d is 1, 2 or 3, is made by reacting a siloxane containing a unit of the formula <FORM:1006777/C3/3> wherein Y is a [M 1/a OOC-], [HOOC-], [R1OOC-] or cyano group, with a water-soluble silicate, many examples of which are given.  If desired, the siloxane can be formed in situ from the corresponding silane.  The starting siloxanes are described in Specifications 882,094 and 882,097.  The novel polymers may also contain units of the formula <FORM:1006777/C3/4> wherein R11 is a saturated or unsaturated hydrocarbon or aminohydrocarbon radical and e is 0, 1, 2 or 3.  In a typical Example (1) b -carbethoxyethyltriethoxysilcane was added to an aqueous solution of KOH and K2SiO3, and the mixture was refluxed for 3 hours after which alcohol and some water were removed by distillation to yield a clear aqueous solution of the polymer which was composed of [KOOC.CH2CH2SiO1.5] and (KO2(SiO units.  Uses.-As corrosion inhibitors in any aqueous liquid which comes into contact with metals, and particularly in anti-freeze and coolant compositions for use in cooling systems of internal combustion engines.  Whereas the anti-freeze compositions are anhydrous or contain, in addition to the alcohol and inhibitor, a small amount of water, the coolant compos tions contain large amounts of water.  The organosilicon inhibitor is usually used in amount of 0.1 to 10 parts (by wt.) per 100 pts. of alcohol, e.g. methanol, ethanol, propanol, glycerol or ethylene, diethylene, triethylene or propylene glycol, and the compositions can contain from 0 to 900 pts. of water per 100 pts. of alcohol. Anti-foam agents, identifying dyes, pH indicators, conventional inhibitors, sealants and anti-creep agents, may also be added. The compositions can be made merely by mixing the ingredients together, or by forming the starting siloxane in situ from a suitable silane, e.g. by adding an anhydrous mixture of the silane, silicate and alcohol (which can be stored per se) to the cooling water of a cooling system.  The compositions can also be used as heat-transfer media and hydraulic fluids and as coating, laminating and moulding resins.