GB2298575A - Biguanide compositions containing a corrosion inhibitor - Google Patents

Biguanide compositions containing a corrosion inhibitor Download PDF

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GB2298575A
GB2298575A GB9604856A GB9604856A GB2298575A GB 2298575 A GB2298575 A GB 2298575A GB 9604856 A GB9604856 A GB 9604856A GB 9604856 A GB9604856 A GB 9604856A GB 2298575 A GB2298575 A GB 2298575A
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biguanide
composition
corrosion inhibitor
corrosion
solution
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John Robert Lawson
Julie Ann Stocks
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Syngenta Ltd
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Zeneca Ltd
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Priority claimed from GBGB9504855.9A external-priority patent/GB9504855D0/en
Priority claimed from GBGB9519180.5A external-priority patent/GB9519180D0/en
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/18—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using inorganic inhibitors
    • C23F11/185—Refractory metal-containing compounds
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N47/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom not being member of a ring and having no bond to a carbon or hydrogen atom, e.g. derivatives of carbonic acid
    • A01N47/40—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom not being member of a ring and having no bond to a carbon or hydrogen atom, e.g. derivatives of carbonic acid the carbon atom having a double or triple bond to nitrogen, e.g. cyanates, cyanamides
    • A01N47/42—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom not being member of a ring and having no bond to a carbon or hydrogen atom, e.g. derivatives of carbonic acid the carbon atom having a double or triple bond to nitrogen, e.g. cyanates, cyanamides containing —N=CX2 groups, e.g. isothiourea
    • A01N47/44—Guanidine; Derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C23F11/167—Phosphorus-containing compounds
    • C23F11/1676—Phosphonic acids

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Description

COMPOSITIONS This invention relates to compositions, in particular to compositions containing a biguanide and a corrosion inhibitor.
Biguanides and their anti-bacterial and anti-fungal properties have been known for many years. GB 702,268 described biguanides, their preparation and their ability to inhibit the growth of certain bacteria and fungi. More recently European Patent Application 0485,079 Al described biguanide solutions having a pH below 5 and suggested their use in geological drilling lubricants, paper mill liquors, metal working fluids and various other applications.
Hitherto compositions containing a biguanide and a corrosion inhibitor apparently have not been known. During our research we have found that many corrosion inhibitors react with biguanides to form a precipitate which has greatly reduced biocidal activity and/or tends to clog the fine filters used in recirculating water systems.
We assessed other biocides for use with corrosion inhibitors but many of these were found to be toxic or unstable, or cause excessive foaming or corrosion of metals.
According to the present invention there is provided a composition comprising a biguanide and a corrosion inhibitor which is compatible with said biguanide.
The biguanide preferably contains at least one, more preferably at least two, group(s) of the Formula (I):
When the biguanide contains at least two groups of Formula (I) it is preferred that the groups of Formula (I) are connected by a divalent organic linking group.
Preferred divalent organic linking groups are alkylene, more preferably C2.12-alkylene, especially C4-8-alkylene; arylene, more preferably C6-10-arylene, especially phenylene; and aralkylene, more preferably C7.11-aralkylene, especially benzylene or xylylene; which optionally contain an ether (.0-), thioether (-S-) or amine (-NH-) link; and combinations of alkylene, arylene an aralkylene groups with or without ether, thioether and amine links.
Preferably each end of the group of Formula (I) is attached to a methylene group.
Examples of divalent organic linking groups include -(CH2)r; -(OH2)8-; -CH2CH(-)(CH2)4CH3; 2-hydroxy-1 ,6-hexylene; 1,4-, 2,3- and 1 3-butylene; 2,5-hexylene; 1 -(methoxycarbonyl)-1, Spentylene; 2,7-heptylene; 3-methyl-l, Shexylene; -CH2. C6H4. CH2-; -CH2O.C6H4.OCHr; -CH20.C6H,O.OCH2-; -(CH2)30(CH2)3-; and -(CH2)2S(CH2)2-.
A preferred biguanide contains a group of the Formula (Il):
wherein n has a value of at least 1 and not greater than 80, preferably from 2 to 40, more preferably from 2 to 20 and especially from 4 to 15; and each X is, independently a divalent organic linking group as hereinbefore described. The nature of the group terminating each end of biguanides containing a group of Formula (I) or (II) is not believed to be critial, provided it does not destroy biocidal activity of the biguanide. Typically acyl, preferably CH3CO; hydrogen; alkyl, preferably C"0-alkyl; acyloxy, preferably OCO(C14alkyl); halo preferably Cl; or cyano groups terminate the biguanide.
A particularly preferred biguanide is of the Formula (III) and salts thereof:
wherein n is from 1 to 40, preferably from 2 to 30, more preferably from 2 to 20, especially 2 to 18, more especially 4 to 15; and each Y independently is -(CH2)3-NH2, -(CH2)3-NH-C(=NH)-NHCN or -(CH2)3-NH-C(=NH)-NH2.
Another preferred biguanide is of the Formula (IV):
wherein W is C1 ,0-alkyl (which may be linear or branched) or optionally substituted phenyl, especially phenyl having 1 or 2 groups selected from C14-alkyl, especially methyl; halo, especially Cl; nitro; cyano; and C4-alkoxy, especially methoxy. It is particularly perferred that W is 4-chlorophenyl or 2-ethyl hexyl.
Biguanides may be prepared by known methods, for example by reacting a compound of the Formula (V):
with a diamine H2N-X-NH2 wherein each X independently is a divalent organic linking group as hereinbefore defined.
Biguanides may also be prepared by reacting H2NC(=NH)NHCN with compounds of Formula H2N-X-NH2 wherein X is as hereinbefore defined.
Methods for preparing biguanides are described in UK Patent specifications Nos. 702,268 and 1,152,243 and any of the polymeric biguanides described therein and mixtures thereof may be used as the biguanide component of compositions of the present invention.
Typically the biguanides are mixtures of polymers in which the polymer chains are of different lengths. Often the number of groups of Formula (I) in the biguanides is from 3 to 80.
In the case of poly(hexamethylene biguanide), which is a preferred biguanide, one finds a group of the Formula (Vl):
wherein the value of n is in the range from 2 to 80, preferably 2 to 40 and especially 4 to 15. The average molecular weight of the poly(hexamethylene biguanide) is preferably from about 1100 to about 3300.
The biguanide may be used as a salt with an inorganic or organic acid, for example as the hydrochloride, acetate or gluconate salt.
When compositions according to the invention are in aqueous solution, for example when supplied as a concentrated liquid form, the aqueous solution preferably has a pH of 6 to 9, more preferably 7 to 8.
The preferred biguanides in accordance with the present invention contain a group of Formula (VI).
One may determine whether a corrosion inhibitor is compatible with a biguanide as follows: A 0.1% solution of corrosion inhibitor in water at pH 7.4 is added to an equal volume of a 0.4% solution of biguanide at pH 7.4 and the mixture is stirred at 200C for 24 hours; the absorbance of the stirred biguanide is measured on a spectrophotometer using a 1 cm cell at a wavelength of 600nm before addition of the corrosion inhibitor (Li) and 24 hours after addition of the corrosion inhibitor (L2) and if (L2 - L1) is less than 1.0 the corrosion inhibitor is compatible with the biguanide and if (1-2 L1) is equal to or greater than 1.0 the corrosion inhibitor is not compatible with the biguanide.
Preferred corrosion inhibitors which are compatible with biguanides are phosphomolybdates and organic amines having at least one and preferably at least two alkylene phosphonic acid groups. The preferred alkylene phosphonic acid group is a methylene phosphonic acid group e.g. N[(CH2)mP03H2j3 and (H203PCH2)2N-(CH2) < N(CH2PO3H2)2, and salts thereof, wherein m is 1 to 6, preferably I to 3, especially 1; and r is 3 to 8, preferably 4 to 7, especially 6. The preferred phosphomolybdates are of the formula [Tn+]q[P(Mo3O10)4]3- wherein n is 1, 2 or 3; q is (3 . n); and T is a cation, especially K, Na, Li, Ca, Zn.
In a preferred embodiment the corrosion inhibitor which is compatible with the biguanide comprises a mixture of a phosphomolybdate and a compound of formula N[(CH2)mPO3H2]3 or a salt thereof. Such mixtures of corrosion inhibitors are preferred because they have good corrosion inhibitor properties in both hard and soft waters. The term hard water has the conventional meaning in that it contains inorganic salts such as calcium and/or magnesium carbonates and/or bicarbonates.
When compositions according to the invention are used in circumstances where they come into contact with metals, especially copper the biocidal activity of the biguanide may be adversely affected. This reduction in biocidal activity can be inhibited by including an azole in the composition.
Therefore, as a further feature of the invention there is provided a composition which additionally comprises an azole.
The azole is preferably a triazole, pyrazole, imidazole, isoxazole, oxazole, isothiazole or thiazole, preferably a triazole. The preferred triazoles are 1,2,3-triazoles, for example 1,2,3-triazole itself or a 1,2,3-triazole having a substituent at one or both of the 4 and 5- positions. Preferred 1,2,3-triazoles having substitents at one or both of the 4- and 5- positions include 4- and 5-phenyl-l 2,3-triazole, optionally substituted naphthotriazole and especially optionally substituted benzotriazole. Preferred optional substituents which may be present on the naphthotriazole and benzotriazole are 01A alkyl, especially methyl; C14-alkoxy, especially methoxy; nitro; amino; halo1 especially chloro.The preferred azole is benzotriazole.
The preferred ratio of biguanide to corrosion inhibitor will depend to some extent on the intended use of the composition and desired level of biocidal activity and corrosion inhibtion for that use. In general, however, the ratio (by weight) of biguanide to corrosion inhibitor is in the range 19:1 to 1:19, preferably 9:1 to 1:9, more preferably 5:1 to 1:5, especially 3:1 to 1:3. The azole, when present, is preferably present in an amount of from 2 to 90% (by weight) relative to the total weight of biguanide and compatible corrosion inhibitor1 more preferably 2 to 50%, especially 5 to 30%.
Compositions according to the invention can be used in quite low amounts to reduce the presence of bacteria and/or fungi in water and at the same time reduce corrosion of metals which come into contact with the water. This has particular value in domestic and industrial recirculating water systems, e.g. cooling and heating waters which come into contact with corrodible metals under conditions which provide a breeding ground for undesirable bacteria and fungi. Compatibility of the corrosion inhibitors with biguanides leads to good biocidal activity for the biguanide and reduces the likelihood of filters being blocked in such systems.
Thus a further feature of the invention provides a composition comprising water; 5 to 500 ppm, preferably 10 to 100 ppm, more preferably 20 to 90 ppm of a biguanide and 10 to 1000 ppm, preferably 20 to 500 ppm, more preferably 25 to 250 ppm of a corrosion inhibitor which is compatible with said biguanide. When present1 the amount of azole is up to 1000 ppm, but is preferably 5 to 500 ppm, more preferably 10 to 100 ppm. The term ppm means parts per million by weight relative to the weight of water.
The invention is further illustrated by the following Examples in which all parts and percentages are by weight unless specified otherwise.
The following abbreviations are used: Mild Steel panels - mild steel panels supplied by Pro-Test Panels, Solihull, England of size 50mm x 20mm x 0.5mm. Before testing these panels were smoothed using emery paper (P120) then immersed in methylated spirits, placed in an ultrasonic bath for 15 minutes, rinsed in tap water and airaried.
Copper panels - copper panels supplied by BDH Limited, Poole, England cut to 70mm x 20mm x 0.1mum. Each panel was scrubbed with an abrasive pad, rinsed with acetone and air-dried.
ExamDle 1 Selecting Compatible Corrosion Inhibitors 2.0 parts by weight of 20% strength aqueous solution of the commercially available biguanide ' "Vantocil" (Vantocil is poly(hexamethylene biguanide) hydrochloride, obtained from Zeneca Limited, Manchester, England) was diluted to 80 parts by volume using distilled water and the pH adjusted to 7.4 using 1M NaOH solution, before diluting to 100 parts by volume with distilled water. This solution was referred to as "Solution A".
The absorbance of solution A (L1) was measured using a 1cm cell in a Perkin Elmer Lambda 15 W-visible spectrophotometer at 600nm and was found to be 0.0.
0.1 parts by weight of a candidate corrosion inhibitor were dissolved in distilled water and the pH adjusted, if necessary, to pH 7.4, then the volume adjusted to 100 parts to give "Solution B".
Equal volumes of Solutions A and B were mixed together at 20 C and optionally stirred for 24 hours, after which the absorbance of the stirred mixture was measured on a Perkin-Elmer Lambda 15 UV-visible spectrophotometer at a wavelength of 600nm, using a 1 cm glass cell, to give absorbance Figure L2. If the (L2 - LI) was less than 1.0 the corrosion inhibitor was deemed compatible with the biguanide.The results of the compatibility tests are shown in Table A below: Table A
Corrosion Inhibitor absorbance absorbance Compatible? (1cm cell) at (1cm cell) at 600nm 600nm after before mixing mixing with with biguanide biguanide solution (L2) solution Sodium benzoate 0.0 3.2 No Sodium salicylate 0.0 3.0 No Sodium bonate 0.0 3.9 No Sodium polyphosphate 0.0 2.7 No Sodium hexametaphosphate 0.0 2.5 No Sodium 1-hydroxyethylidene 0.0 2.4 No phosphonate Na3.[P(Mo3O10)4] 0.0 0.10 Yes N(CH2PO3Na2)3 0.0 0.45 Yes ((NaO3PCH2)2N-)2(CH2)6 0.0 0.05 Yes Footnote to Table A Sodium bonate is the sodium salt of 3-hydroxy-2-naphthoic acid Solution C A stock solution of hard water, hereinafter referred to as solution C, was prepared by dissolving MgCl2.6H2O (3.385 parts), CaCI2.2H20 (4.899 parts) and NaHCO3 (1.008 parts) in 5.0 litres of distilled water. Solution C has a total hardness of 1000ppm, alkalinity 120ppm, total dissolved solids 1259ppm and a pH of about 7.4 at 200C.
Composition 1 To solution C (500ml, prepared as described above) was added H3[P(Mo3010)4] (0.1 parts) and the pH was adjusted to pH 7.4 using 1M NaOH solution.
To the resultant solution was added solution A (12.5ml, prepared as described above) before diluting to 1000ml with distilled water. Compostion 1 thus had a total hardness of 500ppm, alkalinity 60ppm and total dissolved inorganic solids of 629.5ppm. The weight ratio of biguanide to corrosion inhibitor was 1:2 and the content of biguanide and corrosion inhibitor were 50ppm and I OOppm respectively.
ComDosition 2 Composition 2 was prepared exactly as described for composition 1 except that in place of H3[P(Mo3O10)4] there was used 0.1 part of N(CH2PO3H2)3. The weight ratio of biguanide to corrosion inhibitor was 1:2 and the content of biguanide and corrosion inhibitor were 50ppm and 100ppm respectively.
Composition 3 Composition 3 was prepared exactly as described for composition 1 except that in place of H3[P(Mo3O10)4] there was used 0.15 part of (H203PCH2)2N-(CH2)6- N(CH2PO3H2)2. The weight ratio of biguanide to corrosion inhibitor was 1:3 and the content of biguanide and corrosion inhibitor were 50ppm and 150ppm respectively.
Composition 4 To solution C (500ml) was added H3[P(Mo3O10)4] (0.1 part), and benzotriazole (0.025 part) and the pH was adjusted to 7.4 using 1M NaOH solution. To the resultant solution was added solution A (12.5ml) and the whole diluted to 1000ml with distilled water. The weight ratio of biguanide to corrosion inhibitor was 1:2 and the azole was present in an amount of 14% relative to the total amount of biguanide and corrosion inhibitor. The content of biguanide, corrosion inhibitor and benzotriazole were 50ppm, 100ppm and 25ppm respectively.
ComDosition 5 Composition 5 was prepared exactly as described for composition 4 except that in place of H3[P(Mo3O10)4] there was used 0.1 part of N(CH2PO3H2)3.
ComDosition 6 Composition 6 was prepared exactly as described for composition 4 except that in place of 0.1 part of H3[P(Mo3010)4] there was used 0.05 part of H3[P(Mo3010)4l and 0.05 part of N(CH2PO3H2)3. The weight ratio of biguanide to corrosion inhibitors was 1:2, and the content of biguanide, corrosion inhibitors and benzotriazole were 50ppm, 100ppm and 25ppm respectively.
ComDosition 7 Composition 7 was prepared exactly as described for composition 6 except that only 6.25ml of solution A was used. The weight ratio of biguanide to corrosion inhibitors was 1:4 and the benzotriazole was present in an amount of 17% relative to the total amount of biguanide and corrosion inhibitors. The content of biguanide, corrosion inhibitors and benzotriazole were 25ppm,100ppm and 25ppm respectively.
ComDosition 8- ComDarative (no biguanide) To solution C (500ml) was added 0.1 part of H3[P(Mo3O10)4l and the pH adjusted to pH 7.4 using 1M NaOH solution. The resultant solution was diluted to 1000ml with distilled water.
ComDosition 9 - ComDarative (no biguanide) Composition 9 was prepared exactly as composition 8 except that in place of H3[P(Mo3O10)4l there was used 0.1 part of N(CH2PO3H2)3.
Composition 10 - Comparative (no biguanide) Composition 10 was prepared exactly as described for composition 8 except that in place of H3[P(Mo3010)4] there was used 0.1 part of (H203PCH2)2N-(CH2)6- N(CH2PO3H2)2.
Composition 11 - Comparative (no corrosion inhibitor) To solution C (500ml) was added 12.5ml of solution A, and the volume of the mixture was dilited to 1000ml.
ComDosition 12 - ComDarative (no corrosion inhibitor, different biocide) To solution C (500ml) was added 0.35ml of a 14.2% solution in water of the biocide "Kathon" which is not a biguanide. (Kathon is a trade mark of Rohm and Haas and the biocide is a mixture of 2-methyl- and 5-chloro-2-methylisothiazolin-3-one).
The pH was adjusted to 7.4 and the mixture diluted to 1000ml with distilled water.
ComDosition 13- Comparative (Kathon biocide and corrosion inhibitor) Composition 13 was prepared exactly as composition 12 except that 0.10 parts of N(CH2PO3H2)3 was added before adjusting the pH to 7.4 and diluting to 1000ml.
ComDosition 14 - Comoarative ( hard water only) Solution C (500ml) was diluted to 1 000ml using distilled water.
Composition 15- Comparative (Benzotriazole alone) To solution C (500ml) was added 0.025 part of benzotriazole, followed by dilution to 1000ml with distilled water.
ComDosition 16 Comoarative (biguanide and incompatible corrosion inhibitor) To solution C (500ml) was added polyphosphoric acid (0.10 part) and the pH was adjusted to 7.4 using 1M NaOH solution. To the resultant solution was added solution A (12.5ml) and the whole diluted to 1000ml with distilled water. The resultant mixture was opaque due to the formation of a heavy white precipitate.
Comrosition 17 - ComDarative (biguanide and incompatible corrosion inhibitor) Composition 17 was prepared exactly as described for composition 16 except that in place of polyphosphoric acid there was used sodium hexametaphosphate (0.1 part). The resultant mixture was opaque due to the formation of a heavy white precipitate.
ComDosition 18 - ComDarative (biguanide and incompatible corrosion inhibitor) Composition 18 was prepared exactly as described for composition 16 except that in place of polyphosphoric acid there was used 1-hydroxyethylidene diphosponate (0.1 part). The resultant mixture was opaque due to the formation of a heavy white precipitate.
Example 2 - Testina Compositions 1 to 18 were assessed for their ability to inhibit corrosion and inhibit the growth of Staphylococcus aureus ("Sa") using the tests described below.
The results are given in Table B below.
Corrosion Inhibition Weighed copper and mild steel panels were placed in separate glass tubes containing a composition under examination. Tubes containing mild steel panels were shaken at room temperature for 4 days. Tubes containing copper panels were left standing for 14 days. The panels were removed, washed, dried and weighed again.
The mild steel corrosion rates quoted in Table B, were calculated by weight loss in which 1 mpy = a reduction in thickness of 0.0254mm per year. Thus a low mpy indicates a low rate of corrosion.
The copper corrosion rates quoted in Table B are scored from 0 to 5 wherein 0 means no corrosion and 5 means severe corrosion.
Biocidal Activitv These tests were performed to find the lowest concentration at which compositions I to 18 inhibit micro-organism growth (Minimum Inhibitory Concentration, abbreviated to MIC).
The micro-organisms used were Pseudomonas aeruainosa ("Psa") for compositions 1 to 15, and Stachvlococcus aureus ("Sa") for compositions 11 and 16 to 18. These bacteria (Psa and Sa) were tested ovemight at 370C, one colony per 20ml nutrient broth (20ml in 20ml, giving a concentration of 109 viable cells per millilitre of culture).
The following abbreviations are used in Table B: Big = poly(hexamethylene biguanide hydrochloride) from Zeneca Limited, England.
CII = Na3P(Mo3O,0)4 Cl2 = N(CH2PO3H2)3 Cl3 = (Na2O3PCH2)2N-(CH2)6-N(CH2PO3Na2)2 KAT = "Kathon" Biocide (not a biguanide) AZO = Benzotriazole HEDP = 1-hydroxyethylidene diphosphonate &num; = Pitting corrosion &num;&num; = Versus Pseudomonas aeuruginosa * = Comparative Table B
Comp@ Ingredients of composition (ppm) Corrosion test results bioactivity vs. S.a:min inhibitory No conc of biocide (in the composition) which prevented bacterial growth Big Cl1 Cl2 Cl3 KAT* AZO Mild steel: Copper: corrosion corrosion rate in mpy rating 1 50 100 - - - - 0.09 4 0.4 2 50 - 100 - - - 0.08 1-2 0.4 3 50 - - 150 - - 0.35 1-2 0.4 4 50 100 - - - 25 1.14 0 0.4 5 50 - 100 - - 25 0.97 0 0.4 6 50 50 50 - - 25 0.77 0 0.8/0.4 7 25 50 50 - - 25 0.16 0 0.8/0.4 8* - 100 - - - - 0.0 4 not bioactive 9* - - 100 - - - 0.31 0 not bioactive 10* - - - 100 - - 0.24&num; 1-2 not bioactive 11* 50 - - - - - 3.47 4-5 0.4 12* - - - - 50 - 13.6 5 0.4 13* - - 100 - 50 - 6.4 5 0.4 14* - - - - - - 5.3 4 not bioactive 15* - - - - - 25 5.5 0 not bioactive 16* 50 100ppm polyphosphoric acid not done 32&num;&num; 17* 50 100ppm sodium hexamethaphosphate not done 62.5&num;&num; 18* 50 100ppm HEDP not done 16&num;&num; 11* 50 - 3.47 4-5 2&num;&num;

Claims (10)

  1. CLAIMS 1. A composition comprising a biguanide and a corrosion inhibitor which is compatible with the biguanide.
  2. 2. A composition according to claim 1 wherein the biguanide contains at least two groups of the formula (I):
  3. 3. A composition as claimed in either claim 1 or claim 2 wherein said compatible corrosion inhibitor is a phosphomolybdate salt.
  4. 4. A composition as claimed in either claim 1 or 2 wherein the corrosion inhibitor is an organic amine having at least one alkylene phosphonic acid group.
  5. 5. A composition as claimed in claim 4 wherein the amine is (H2O3PCH2)2N-(CH2)rN(CH2PO3H2)2 or N[(CH2)mPO3H2]3, or a salt thereof, wherein r is 3 to 8 and m is 1 to 6.
  6. 6. A composition as claimed in either claim 1 or 2 wherein the corrosion inhibitor is a mixture comprising a phosphomolybdate and N[(CH2)mPO3H2]3, or salts thereof, wherein m is 1 to 6.
  7. 7. A composition as claimed in any one of claims 1 to 6 which further comprises an azole.
  8. 8. A composition as claimed in claim 7 wherein the azole is 1,2,3benzotriazole.
  9. 9. Use of a composition as claimed in any one of claims 1 to 8 to reduce the amount of bacteria andlor fungi in water and at the same time reduce corrosion of metals which come into contact with the water.
  10. 10. A composition comprising water, 5 to 500ppm of a biguanide, 10 to 1000ppm of a corrosion inhibitor which is compatible with the biguanide, and 0 to 1000ppm of an azole.
GB9604856A 1995-03-10 1996-03-07 Biguanide compositions containing a corrosion inhibitor Withdrawn GB2298575A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9504855.9A GB9504855D0 (en) 1995-03-10 1995-03-10 Compositions
GBGB9519180.5A GB9519180D0 (en) 1995-09-20 1995-09-20 Compositions

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GB9604856D0 GB9604856D0 (en) 1996-05-08
GB2298575A true GB2298575A (en) 1996-09-11

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GB (1) GB2298575A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997028091A1 (en) * 1996-01-29 1997-08-07 Bausch & Lomb Incorporated Swimming pool treatment
US5885562A (en) * 1995-04-03 1999-03-23 Chesebrough-Pond's Usa Co., Division Of Conopco, Inc. Deodorant compositions
EP2470009A1 (en) * 2009-08-24 2012-07-04 Arch Chemicals, Inc. Compositions for treating water systems

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909200A (en) * 1967-05-22 1975-09-30 Petrolite Corp Use of guanidine derived compounds as corrosion inhibitors

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909200A (en) * 1967-05-22 1975-09-30 Petrolite Corp Use of guanidine derived compounds as corrosion inhibitors

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WPI Abstract Acc. No. 94-103492/13 and FR002695297A *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5885562A (en) * 1995-04-03 1999-03-23 Chesebrough-Pond's Usa Co., Division Of Conopco, Inc. Deodorant compositions
WO1997028091A1 (en) * 1996-01-29 1997-08-07 Bausch & Lomb Incorporated Swimming pool treatment
US5935518A (en) * 1996-01-29 1999-08-10 Bausch & Lomb Incorporated Swimming pool treatment
EP2470009A1 (en) * 2009-08-24 2012-07-04 Arch Chemicals, Inc. Compositions for treating water systems
EP2470009A4 (en) * 2009-08-24 2013-06-05 Arch Chem Inc Compositions for treating water systems

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