WO2016105941A1 - Corrosion inhibitors and methods of using corrosion inhibitors - Google Patents
Corrosion inhibitors and methods of using corrosion inhibitors Download PDFInfo
- Publication number
- WO2016105941A1 WO2016105941A1 PCT/US2015/064593 US2015064593W WO2016105941A1 WO 2016105941 A1 WO2016105941 A1 WO 2016105941A1 US 2015064593 W US2015064593 W US 2015064593W WO 2016105941 A1 WO2016105941 A1 WO 2016105941A1
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- WO
- WIPO (PCT)
- Prior art keywords
- salt
- cleaning composition
- alkaline
- amount
- weight
- Prior art date
Links
- 238000005260 corrosion Methods 0.000 title claims abstract description 119
- 230000007797 corrosion Effects 0.000 title claims abstract description 119
- 239000003112 inhibitor Substances 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 29
- 239000000203 mixture Substances 0.000 claims abstract description 198
- 238000004140 cleaning Methods 0.000 claims abstract description 168
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 claims abstract description 160
- 229960005070 ascorbic acid Drugs 0.000 claims abstract description 79
- 235000010323 ascorbic acid Nutrition 0.000 claims abstract description 78
- 239000011668 ascorbic acid Substances 0.000 claims abstract description 78
- 150000003839 salts Chemical class 0.000 claims abstract description 73
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical compound OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 claims description 72
- 150000003014 phosphoric acid esters Chemical class 0.000 claims description 48
- 230000002401 inhibitory effect Effects 0.000 claims description 43
- 150000003013 phosphoric acid derivatives Chemical class 0.000 claims description 40
- 229910052751 metal Inorganic materials 0.000 claims description 26
- 239000002184 metal Substances 0.000 claims description 26
- NJGCRMAPOWGWMW-UHFFFAOYSA-N octylphosphonic acid Chemical compound CCCCCCCCP(O)(O)=O NJGCRMAPOWGWMW-UHFFFAOYSA-N 0.000 claims description 9
- NLBSQHGCGGFVJW-UHFFFAOYSA-N 2-carboxyethylphosphonic acid Chemical compound OC(=O)CCP(O)(O)=O NLBSQHGCGGFVJW-UHFFFAOYSA-N 0.000 claims description 7
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 6
- 235000019832 sodium triphosphate Nutrition 0.000 claims description 6
- UNXRWKVEANCORM-UHFFFAOYSA-I triphosphate(5-) Chemical compound [O-]P([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O UNXRWKVEANCORM-UHFFFAOYSA-I 0.000 claims description 6
- 230000000116 mitigating effect Effects 0.000 claims description 5
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 4
- 229920000642 polymer Polymers 0.000 claims description 4
- LJKDOMVGKKPJBH-UHFFFAOYSA-L 2-ethylhexyl phosphate Chemical compound CCCCC(CC)COP([O-])([O-])=O LJKDOMVGKKPJBH-UHFFFAOYSA-L 0.000 claims description 3
- 239000004094 surface-active agent Substances 0.000 claims description 3
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 2
- 150000002148 esters Chemical class 0.000 claims description 2
- 230000001419 dependent effect Effects 0.000 claims 1
- 229910052782 aluminium Inorganic materials 0.000 description 29
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 29
- 230000004580 weight loss Effects 0.000 description 10
- 230000005764 inhibitory process Effects 0.000 description 8
- 239000002253 acid Substances 0.000 description 7
- -1 for example Chemical class 0.000 description 7
- 229910001369 Brass Inorganic materials 0.000 description 5
- 239000010951 brass Substances 0.000 description 5
- 238000009472 formulation Methods 0.000 description 5
- 150000003009 phosphonic acids Chemical class 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 239000011734 sodium Substances 0.000 description 5
- 238000004659 sterilization and disinfection Methods 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 4
- 239000008367 deionised water Substances 0.000 description 4
- 229910052708 sodium Inorganic materials 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- HWGNBUXHKFFFIH-UHFFFAOYSA-I pentasodium;[oxido(phosphonatooxy)phosphoryl] phosphate Chemical compound [Na+].[Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O HWGNBUXHKFFFIH-UHFFFAOYSA-I 0.000 description 3
- UEZVMMHDMIWARA-UHFFFAOYSA-M phosphonate Chemical compound [O-]P(=O)=O UEZVMMHDMIWARA-UHFFFAOYSA-M 0.000 description 3
- 229910052700 potassium Inorganic materials 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- 159000000000 sodium salts Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- OVSKIKFHRZPJSS-UHFFFAOYSA-N 2,4-D Chemical compound OC(=O)COC1=CC=C(Cl)C=C1Cl OVSKIKFHRZPJSS-UHFFFAOYSA-N 0.000 description 2
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- DUYCTCQXNHFCSJ-UHFFFAOYSA-N dtpmp Chemical compound OP(=O)(O)CN(CP(O)(O)=O)CCN(CP(O)(=O)O)CCN(CP(O)(O)=O)CP(O)(O)=O DUYCTCQXNHFCSJ-UHFFFAOYSA-N 0.000 description 2
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- SIOXPEMLGUPBBT-UHFFFAOYSA-N picolinic acid Chemical compound OC(=O)C1=CC=CC=N1 SIOXPEMLGUPBBT-UHFFFAOYSA-N 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000001954 sterilising effect Effects 0.000 description 2
- BPSYZMLXRKCSJY-UHFFFAOYSA-N 1,3,2-dioxaphosphepan-2-ium 2-oxide Chemical compound O=[P+]1OCCCCO1 BPSYZMLXRKCSJY-UHFFFAOYSA-N 0.000 description 1
- NPSJHQMIVNJLNN-UHFFFAOYSA-N 2-ethylhexyl 4-nitrobenzoate Chemical compound CCCCC(CC)COC(=O)C1=CC=C([N+]([O-])=O)C=C1 NPSJHQMIVNJLNN-UHFFFAOYSA-N 0.000 description 1
- 239000004808 2-ethylhexylester Substances 0.000 description 1
- FEHSBMNKLYTBCO-UHFFFAOYSA-N C(CCCCCCC)P(O)(O)=O.P(O)(O)=O Chemical compound C(CCCCCCC)P(O)(O)=O.P(O)(O)=O FEHSBMNKLYTBCO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 206010011409 Cross infection Diseases 0.000 description 1
- CIWBSHSKHKDKBQ-MVHIGOERSA-N D-ascorbic acid Chemical compound OC[C@@H](O)[C@@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-MVHIGOERSA-N 0.000 description 1
- ZZZCUOFIHGPKAK-UHFFFAOYSA-N D-erythro-ascorbic acid Natural products OCC1OC(=O)C(O)=C1O ZZZCUOFIHGPKAK-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 239000002211 L-ascorbic acid Substances 0.000 description 1
- 235000000069 L-ascorbic acid Nutrition 0.000 description 1
- 206010029803 Nosocomial infection Diseases 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229920002594 Polyethylene Glycol 8000 Polymers 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- 101000983338 Solanum commersonii Osmotin-like protein OSML15 Proteins 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229930003268 Vitamin C Natural products 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- YDONNITUKPKTIG-UHFFFAOYSA-N [Nitrilotris(methylene)]trisphosphonic acid Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CP(O)(O)=O YDONNITUKPKTIG-UHFFFAOYSA-N 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- MRNZSTMRDWRNNR-UHFFFAOYSA-N bis(hexamethylene)triamine Chemical compound NCCCCCCNCCCCCCN MRNZSTMRDWRNNR-UHFFFAOYSA-N 0.000 description 1
- 238000012993 chemical processing Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- DKPHLYCEFBDQKM-UHFFFAOYSA-H hexapotassium;1-phosphonato-n,n-bis(phosphonatomethyl)methanamine Chemical compound [K+].[K+].[K+].[K+].[K+].[K+].[O-]P([O-])(=O)CN(CP([O-])([O-])=O)CP([O-])([O-])=O DKPHLYCEFBDQKM-UHFFFAOYSA-H 0.000 description 1
- 238000011086 high cleaning Methods 0.000 description 1
- 208000015181 infectious disease Diseases 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- XMYQHJDBLRZMLW-UHFFFAOYSA-N methanolamine Chemical compound NCO XMYQHJDBLRZMLW-UHFFFAOYSA-N 0.000 description 1
- 229940087646 methanolamine Drugs 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- 125000002347 octyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229940081066 picolinic acid Drugs 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229960004418 trolamine Drugs 0.000 description 1
- 235000019154 vitamin C Nutrition 0.000 description 1
- 239000011718 vitamin C Substances 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- 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
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/0005—Other compounding ingredients characterised by their effect
- C11D3/0073—Anticorrosion compositions
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/16—Organic compounds
- C11D3/20—Organic compounds containing oxygen
- C11D3/2096—Heterocyclic compounds
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/16—Organic compounds
- C11D3/36—Organic compounds containing phosphorus
- C11D3/361—Phosphonates, phosphinates or phosphonites
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/16—Organic compounds
- C11D3/36—Organic compounds containing phosphorus
- C11D3/362—Phosphates or phosphites
-
- 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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
- C23G1/16—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions using inhibitors
- C23G1/18—Organic inhibitors
-
- C11D2111/16—
Abstract
There is presented an alkaline corrosion inhibitor composition comprising ascorbic acid or a salt thereof, alkaline cleaning compositions comprising the alkaline corrosion inhibitor composition, and methods of using the same.
Description
CORROSION INHIBITORS AND METHODS OF USING CORROSION
INHIBITORS
Cross-Reference to Related Application
This application claims priority to Great Britain Patent Application Serial No. 1423165.8 filed on December 24, 2014, the disclosure of which is incorporated herein by reference in its entirety. Field of the Invention
The disclosure pertains to compositions and methods useful for minimizing or inhibiting corrosion. In particular, the disclosure pertains to minimizing or inhibiting corrosion of metal articles during cleaning with alkaline cleaning compositions.
Background of the Invention
Effective cleaning, sterilization and disinfection of articles are of the upmost importance in many industries, such as healthcare, the food industry, etc. For example, reusable medical instruments, such as surgical instruments or probes, including flexible endoscopes, must be cleaned and sterilized/disinfected after every use to ensure that the risks of cross infection between patients is minimized. Medical instruments that are thermally stable are sterilized by processing at a high temperature, once cleaned. Those medical instruments that may be temperature sensitive, especially at relatively high temperatures, must be disinfected by chemical processing, i.e. by treatment with chemical compositions. Any cleaning composition to be used in these situations must be able to clean the articles effectively to ensure effective disinfection following the cleaning step of those instruments. Accordingly, typical cleaning compositions used in the art are aggressive and often use alkaline conditions to provide a high cleaning performance and therefore, guarantee a high level of sterilization/disinfection.
However, many articles that are to be cleaned comprise metallic components, and the moderately or highly alkaline cleaning compositions typically used are often highly aggressive towards metals, such as steel, stainless steel, copper, zinc, brass, aluminum, and especially anodized aluminum, for example. Such aggressive formulations can corrode the metal of the articles to be cleaned over time, and discolor or degrade any plastic-based portions that may be present. Therefore, the metallic components of the articles can become corroded and degraded, potentially forming additional sites for bacterial colonies to be established, and may even require the articles to be repaired or replaced. One method of inhibiting corrosion in suitable cleaning compositions is the addition of a corrosion inhibitor. For example, it is known in the art to include a phosphonic acid or a phosphoric acid ester in a cleaning composition to inhibit the rate of metal corrosion in aqueous environments. However, corrosion of metallic components still occurs, if at a reduced rate.
Therefore, there exists a need for improved cleaning compositions that can provide the required high level of cleaning and sterilization action, whilst inhibiting or preventing any corrosive action of the cleaning composition on metals. Summary of the Invention
Alkaline corrosion inhibitor compositions are provided that comprise ascorbic acid or a salt thereof. The compositions may further comprise at least one phosphonic acid, and/or at least one phosphoric acid ester, and/or at least one phosphate salt. Such corrosion inhibitor compositions may be used with cleaning compositions, and are especially suited to be used with alkaline cleaning compositions.
In preferred embodiments, the at least one phosphonic acid comprises octyl phosphonic acid, and/or 2-carboxyethyl phosphonic acid, or a salt thereof.
An alkaline cleaning composition is provided that comprises at least one surfactant, and ascorbic acid or a salt thereof. Typically, the cleaning composition has a pH greater than 8.5, 9.5 or 11.0. The alkaline cleaning composition may further comprise at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof,
and/or at least one phosphate salt. For example, the alkaline cleaning composition may comprise the alkaline corrosion inhibitor composition. Alternatively, the alkaline corrosion inhibitor composition may be added to the alkaline cleaning composition prior to use or simultaneously dosed in the washing solution.
In some aspects, the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is present in the cleaning composition in an amount ranging from about 0.1 to 5.0 weight % and the ascorbic acid is present in an amount ranging from about 0.2 to 10.0 weight %. In certain aspects, the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is present in the cleaning composition in an amount ranging from about 0.1 to 1.0 weight % and the ascorbic acid is present in an amount ranging from about 0.1 to 2.0 weight %. In some aspects, the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is present in the cleaning composition in an amount of about 0.5 weight % and the ascorbic acid is present in an amount of about 1.0 weight %.
Methods of cleaning articles using an alkaline cleaning composition whilst inhibiting corrosion of those articles by the alkaline cleaning composition is also provided. An effective amount of the alkaline corrosion inhibitor composition may be added to an alkaline cleaning composition to produce an alkaline corrosion inhibiting cleaning composition, and the article may then be cleaned with the alkaline corrosion inhibiting cleaning composition. Alternatively, an alkaline cleaning composition may comprise the alkaline corrosion inhibitor composition, and therefore, the alkaline cleaning composition may be an alkaline corrosion inhibiting cleaning composition. In a further alternative embodiment, the alkaline cleaning composition may comprise at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt, and the alkaline corrosion inhibitor composition may comprise ascorbic acid and be devoid of at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt.
Typically, the alkaline corrosion inhibiting cleaning composition is diluted prior to use.
In certain embodiments of the invention, an effective amount of alkaline corrosion inhibitor composition is such that the amount of phosphonic acid within the corrosion inhibiting cleaning composition ranges from about 0.1 to 5.0 weight % and the amount of ascorbic acid within the corrosion inhibiting cleaning composition ranges from about 0.2 to 10.0 weight %, and the corrosion inhibiting cleaning composition is then diluted with water to between 10% original concentration to 0.1% original concentration. For example, the corrosion inhibiting cleaning composition may be diluted to 10%, 5%, 1% or preferably 0.7, 0.6 or 0.5% the original concentration prior to use. Typically, the articles to be cleaned are metal articles or comprise metallic components. The methods can include the steps of providing an article to be cleaned, providing an effective amount of the corrosion inhibitor composition, providing a cleaning composition, adding the corrosion inhibitor composition to the cleaning composition to form a corrosion inhibiting cleaning composition and cleaning the article with the corrosion inhibiting cleaning composition.
The articles are typically surgical instruments. For example, the articles may be flexible endoscopes. In some aspects, the step of cleaning the article with the corrosion inhibiting cleaning composition is carried out automatically. For example, the article may be processed in a cleaning machine using the alkaline cleaning composition. In some aspects, the step of cleaning the article with the corrosion inhibiting cleaning composition is carried out manually.
The foregoing has outlined rather broadly the features and technical advantages of the present disclosure in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter that form the subject of the claims. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent embodiments do not depart from the spirit or scope of the disclosure as set forth in the appended claims.
Embodiments of the present invention will now be described, by way of non-limiting example, with reference to the accompanying drawings. Description of the Figures
Figure 1 is a chart showing weight loss of anodized aluminum plates immersed in an alkaline cleaning composition at room temperature containing (A) no corrosion inhibitors (B) ascorbic acid only (C) octyl phosphonic acid only and (D) ascorbic acid and octyl phosphonic acid.
Figure 2 is a chart showing average weight loss of blue anodized aluminum plates immersed in an alkaline cleaning composition at 55°C, where AC is Alkaline Cleaning composition, "Vit C" is ascorbic acid, and P is octyl phosphonic acid.
Figure 3 is a chart showing average weight loss of blue anodized aluminum plates exposed to an alkaline cleaning composition at 55 °C during machine washing (5 runs), where AC is an alkaline cleaning composition, "Vit C" is ascorbic acid, and P2 is 2-carboxyethyl phosphonic acid.
Figure 4 is a chart showing average weight loss of red anodized aluminum plates exposed to an alkaline cleaning composition at 55 °C during machine washing (5 runs), where AC is an alkaline cleaning composition, "Vit C" is ascorbic acid, and P2 is 2-carboxyethyl phosphonic acid.
Figure 5 is a chart showing average weight loss of aluminum plates exposed to an alkaline cleaning composition at 55 °C during machine washing (5 runs), where AC is an alkaline cleaning composition, "Vit C" is ascorbic acid, and P2 is 2-carboxyethyl phosphonic acid. Figure 6 is a chart showing average weight loss of brass plates exposed to an alkaline cleaning composition at 55°C during machine washing, where AC is an alkaline cleaning composition, "Vit C" is ascorbic acid, and P2 is 2-carboxyethyl phosphonic acid.
Figure 7 is a chart showing the average weight loss of blue anodized aluminum plates immersed in an alkaline cleaning composition at 55 °C, where AC is an alkaline cleaning composition, "Vit C" is ascorbic acid, Hordaphos MDAH is phosphoric acid, 2-ethylhexyl ester (Clariant), TEA is Methanol amine and TP phosphate is tripolyphosphate.
Detailed Description of Preferred Embodiments
The present disclosure provides a treatment including compositions and methods useful for inhibiting corrosion of metal articles during cleaning with alkaline and mild-alkaline cleaning compositions.
As used herein, "corrosion inhibitor" is intended to refer to at least one of, or any combination of, the disclosed corrosion inhibitors, corrosion inhibitor intermediates, and corrosion inhibitor product formulations.
As used herein, "an effective amount" is intended to refer to an amount by which the referred to component should be present to perform its intended function. For example, an effective amount of a corrosion inhibitor is an amount of that component that at least partially inhibits corrosion.
As used herein, "ascorbic acid", also known as "Vitamin C", is intended to refer to L- ascorbic acid, D-ascorbic acid, salts thereof, or a mixture thereof. As used herein, pH values are those measured at room temperature.
It is vital in many industries that the articles or instruments used in those industries are clean and/or sterilized / disinfected. For example, in the healthcare industry, it is crucial that surgical instruments are cleaned and sterilized after every use to ensure that the risk of contamination and infection are minimized. Many of these articles are metallic, or comprise metallic components, and these metallic articles may suffer from corrosion if cleaned with an aggressive cleaning composition. However, it is often of more importance that the articles are cleaned as thoroughly as possible, than ensuring that corrosion of the articles is prevented. Therefore, alkaline cleaning compositions are often used, with high
pH (such as pH 12, for example), that provide a high quality of cleaning, but also can corrode the articles over time.
Accordingly, it would be advantageous to provide a cleaning composition that may inhibit the corrosion of articles to be cleaned without inhibiting the cleaning action of the cleaning composition.
According to a first aspect of the invention, there is presented an alkaline corrosion inhibitor composition comprising ascorbic acid or a salt thereof.
Typically, alkaline cleaning compositions, once diluted down to the concentrations that are to be used, have a pH between 9.0 and 13.0. The use of ascorbic acid or a salt thereof in such alkaline conditions is contraindicated by ascorbic acid being ready oxidized and broken down in those conditions. In addition, the use of ascorbic acid would not be expected to improve the corrosion inhibition properties of a cleaning composition. However, the inventors have surprisingly found that alkaline cleaning compositions comprising ascorbic acid and no additional corrosion inhibitor provide effective corrosion inhibition for metal articles being cleaned repeatedly using the alkaline cleaning compositions.
The inventors have found that alkaline cleaning compositions comprising ascorbic acid or a salt thereof are especially effective at inhibiting corrosion of aluminum and anodized aluminum articles. The alkaline corrosion inhibitor composition may further comprise at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt.
Surprisingly, the inventors have found that the use of an alkaline corrosion inhibitor composition comprising both ascorbic acid and a phosphonic acid, phosphoric acid ester, or phosphate salt in combination provides greater corrosion inhibition of metals in alkaline conditions than would be the case for alkaline solutions or compositions that do not comprise ascorbic acid or a phosphonic acid, or a phosphoric acid ester, or phosphate salt,
or that comprise either ascorbic acid or a phosphonic acid , phosphoric acid ester, or phosphate salt alone.
The at least one phosponic acid may include a plurality of phosphonic acid or phosphonates including, for example, organic phosphonate, condensed phosphonate, mixtures thereof, or the like. Suitable condensed phosphonates include sodium and potassium orthophosphonate, sodium and potassium pyrophosphonate, sodium and potassium tripolyphosphonate, sodium hexametaphosphonate. Exemplary commercially available phosphonic acids, phosphoric acid esters and phosphate salts include phosphonates sold under the trade name DEQUEST® from Thermphos or Cublen® from Zschimmer & Schwarz or Briquest® from Rhodia including, for example, l-hydroxyethylidine-l,l-diphosphonic acid (CH3C(P03H2)20H) (HEDP) DEQUEST® 2010; amino(tri(methylenephosphonic acid)), (N[CH2P03H2]3), available as DEQUEST® 2000, or as Cublen® AP5 from Zschimmer & Schwarz, or as Briquest® 301-50A from Rhodia; ethylenediamine[tetra(methylenephoshonic acid)], available from Thermphos as DEQUEST® 2041; diethylene triamine penta(methylene phosphonic acid), available from Thermphos as DEQUEST® 2066, or as Cublen® D 3217S from Zschimmer & Schwarz; 2-phosphonobutane-l,2-tricarboxylic acid available from Lanxess as Bayhibit® AM. Phosphate esters are also available from Solvia under Rhodafac range (RHODAFAC® AAP, RHODAFAC® ARB/70, RHODAFAC® ARB/90, RHODAFAC® ASI80, RHODAFAC® ASI HW, RHODAFAC® BN-936/S, RHODAFAC® H-66 E, RHODAFAC® HA-70, RHODAFAC® LO/529-E, RHODAFAC® LO-l l/ALA, RHODAFAC® LO-529, RHODAFAC® MB, RHODAFAC® PA15, RHODAFAC® PA23, RHODAFAC® PA32, RHODAFAC® PE- 510, RHODAFAC® RA-600 E, RHODAFAC® RA-600, RHODAFAC® RE-610 E, RHODAFAC® RE-610, RHODAFAC® RM-510 E, RHODAFAC® RP-710, RHODAFAC® RS-410, RHODAFAC® RS-610 E, RHODAFAC® RS-610, RHODAFAC® RS-610/A25, RHODAFAC® RS-710 E, RHODAFAC® RS-710, RHODAFAC® RS-960. Phosphoric acid esters are also available from Clariant; Hordaphos MDAH, Hordaphos MDGB. Further phosphoric acid esters are available from BASF: Korantin® LUB and Korantin® SMK.
The phosphonate can include: an organic -phosphonic acid and alkali metal salts thereof. Exemplary suitable organic phosphonates for use herein include:
1- hydroxyethane-l,l-diphosphonic acid, CH3C(OH)[PO(OH)2]2;
aminotri(methylenephosphonic acid): Ν[Ο¾Ρ0(0Η)2]3 ;
aminotri(methylenephosphonate), sodium salt; 2-hydroxyethyliminobis
(methylenephosphonic acid), HOCH2CH2N[CH2PO(OH)2]2;
diethylenetriaminepenta(methylene phosphonic acid),
(HO)2POCH2N[CH2CH2N[CH2PO(OH)2]2]2; diethylenetriaminepenta(methylene- phosphonate), sodium salt, CgH(28 _x)N3Nax0i5P5 where x=7;
hexamethylenediamine(tetramethylene phosphonate), potassium salt, CioH(28_x)N2KxOi2P4 where x=6; bis(hexamethylene)triamine (pentamethylenephosphonic acid),
(H02)POCH2N[CH2)6N[CH2PO(OH)2]2]2; and phosphorus acid H3P03; and other similar organic phosphonates, and mixtures thereof; or salts thereof, such as the alkali metal salts, ammonium salts, or alkyloyl amine salts, such as mono-, di-, or tetra-ethanolamine salts, picolinic acid or di-picolinic acid salts or mixtures thereof.
Some further examples of suitable organic phosphonic acids including their corresponding phosphonates include:
Alkyl (C1-C20) phosphonic acid:
R[PO(OH)2], where R is C1-C20;
2- carboxy phosphonic acid:
COOH[PO(OH)2];
2-carboxy alkyl (C1-C20) phosphonic acid:
COOHR[PO(OH)2], where R is C1-C20.
In one preferred embodiment, the at least one phosphonic acid comprises octyl phosphonic acid (alkyl (C8) phosphonic acid). In another preferred embodiment the at least one phosphonic acid comprises 2-carboxyethyl phosphonic acid (2-carboxyalkyl (C2) phosphonic acid).
In a further alternative preferred embodiment, the at least one phosphate salt comprises tripolyphosphate. In a yet further alternative preferred embodiment, the at least one phosphoric acid ester comprises phosphoric acid, 2-ethylhexyl ester. In a further
alternative preferred embodiment, the at least one phosphoric acid ester comprises phosphoric acid, mixed esters with butyl alcohol and ethylene glycol.
It will be appreciated by the skilled person that the alkaline corrosion inhibitor composition may comprise any suitable combination of phosphonic acids, phosphoric acid esters, salts thereof and phosphate salts. For example, the alkaline corrosion inhibitor composition may comprise a plurality of phosphonic acids, such as two, three, four or more phosphonic acids. Alternatively, the alkaline corrosion inhibitor composition may comprise a phosphonic acid and a phosphoric acid ester. Further variations will be readily appreciated by the skilled person.
The corrosion inhibitor composition may be provided as a dry powder, tablet or block. Accordingly, the corrosion inhibitor composition may be added to a liquid alkaline cleaning composition immediately prior to use. The corrosion inhibitor composition may be included in the formulation of the alkaline cleaning composition and the alkaline cleaning composition may be provided as a dry powder, tablet or block.
In preferred embodiments comprising ascorbic acid and at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt, the ratio of the amount of ascorbic acid to the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is approximately 3:1, 2.5:1, 2:1, 1.5:1, or 1: 1. Accordingly, the ratio of ascorbic acid to the at least one phosphonic acid or salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is approximately from 3:1 to 1:1, from 2.5:1 to 1:1, from 2:1 to 1:1 or from 1.5:1 to 1:1. Preferably, the ratio is approximately 2:1.
According to a second aspect of the invention there is provided an alkaline cleaning composition comprising the corrosion inhibitor composition of the first aspect.
Preferably, the alkaline cleaning composition further comprises at least one surfactant and/or polymer.
In preferred embodiments, the alkaline cleaning composition has a pH greater than 8.5. Preferably, the cleaning composition has a pH greater than 9.5. More preferably, the alkaline cleaning composition has a pH greater than 11.0. In further preferred embodiments, the alkaline cleaning composition has a pH between 8.5 and 14.0, between 10.0 and 14.0, or between 11.0 and 14.0.
An alkaline cleaning composition comprising both a phosphonic acid and/or phosphoric acid ester and/or phosphate salt, and ascorbic acid has been found to provide surprising corrosion inhibitory properties far greater than merely the sum of corrosion inhibition of the phosphonic acid and/or phosphoric acid ester and/or phosphate salt, or ascorbic acid alone.
In embodiments where the alkaline corrosion inhibitor composition comprises at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt, the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt may be present in an amount ranging from about 0.1 to 5.0 weight %, and the ascorbic acid may be present in an amount ranging from about 0.2 to 10.0 weight %. The at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt may be present in an amount ranging from about 0.1 to 3.0 weight %, and the ascorbic acid may be present in an amount ranging from about 0.1 to 5.0 The at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt may be present in an amount ranging from about 0.1 to 2.0 weight %, and the ascorbic acid may be present in an amount ranging from about 0.1 to 4.0 weight %..0 weight %.
Preferably, the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is present in an amount ranging from about 0.1 to 1.0 weight % and the ascorbic acid is present in an amount ranging from about 0.1 to 2.0 weight %. More preferably, the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is present in an amount of about 0.5 weight % and the ascorbic acid is present in an amount of about 1.0 weight %.
The invention extends in a third aspect to a method of mitigating corrosion of metallic articles during cleaning, the method comprising the steps:
(a) providing a metal article to be cleaned;
(b) providing an effective amount of the alkaline corrosion inhibitor according to the first aspect;
(c) providing an alkaline cleaning composition;
(d) adding the alkaline corrosion inhibitor to the alkaline cleaning composition to produce an alkaline corrosion inhibiting cleaning composition; and
(e) cleaning the metal article with the alkaline corrosion inhibiting cleaning composition.
Step (e) may be carried out automatically, be a processing machine, for example. Step (e) may be carried out manually.
An effective amount of corrosion inhibitor may be such that the amount of the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt within the corrosion inhibiting cleaning composition ranges from about 0.1 to 5.0 weight %, and the amount of ascorbic acid within the corrosion inhibiting cleaning composition ranges from about 0.2 to 10.0 weight %. An effective amount of corrosion inhibitor may be such that the amount of the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt within the corrosion inhibiting cleaning composition ranges from about 0.1 to 3.0 weight %, and the amount of ascorbic acid within the corrosion inhibiting cleaning composition ranges from about 0.1 to 5.0. An effective amount of corrosion inhibitor may be such that the amount of the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt within the corrosion inhibiting cleaning composition ranges from about 0.1 to 2.0 weight %, and the amount of ascorbic acid within the corrosion inhibiting cleaning composition ranges from about 0.1 to 4.0 weight %..0 weight %.
An effective amount of corrosion inhibitor may be such that the amount of the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof,
and/or at least one phosphate salt within the corrosion inhibiting cleaning composition ranges from about 0.1 to 1.0 weight %, and the amount of ascorbic acid within the corrosion inhibiting cleaning composition ranges from about 0.2 to 2.0 weight %. An effective amount of corrosion inhibitor is such that the amount of the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt within the corrosion inhibiting cleaning composition is about 0.5 weight % and the amount of ascorbic acid within the corrosion inhibiting cleaning composition is about 1.0 weight %. Preferably, the metallic articles are surgical instruments. The surgical instruments are flexible endoscopes, for example.
The inventors have found that using alkaline cleaning compositions comprising the alkaline corrosion inhibitor according to the first aspect are especially effective in the method of the present aspect at inhibiting corrosion of aluminum and anodized aluminum articles. Therefore, the method may be a method of cleaning aluminum and/or anodized aluminum articles.
According to a fourth aspect of the invention there is provided a method of mitigating corrosion of metallic articles during cleaning, the method comprising the steps:
(a) providing a metal article to be cleaned;
(b) providing an effective amount of the alkaline cleaning composition according to the second aspect;
(c) cleaning the metal article with the alkaline cleaning composition.
Examples
Procedures were set up to test the effectiveness of the presently disclosed alkaline corrosion inhibitor compositions in mitigating corrosion of metal plates in alkaline environments.
Immersion testing of anodized aluminum at room temperature
12cm by 6cm by 0.1cm anodized aluminum plates were weighed, and then immersed and suspended in an alkaline cleaning composition diluted to 0.6% the original concentration in deionised water for three weeks. After each week, the plates were taken out of the cleaning composition, dried and weighed, and the cleaning composition solution changed. The plates were then reimmersed in the new cleaning composition.
Four alternative cleaning compositions were made (pH 9.5), based upon cleaning composition A, one without either ascorbic acid or a phosphonic acid, one with ascorbic acid, one with a phosphonic acid, and one with both ascorbic acid and phosphonic acid.
The cleaning composition A plus ascorbic acid and the phosphonic acid octyl phosphonic acid is shown in Table 1, and the final 0.6% solution in deionized water was pH 9.5.
When anodized aluminum plates were exposed to an alkaline cleaning composition that did not comprise a phosphonic acid or ascorbic acid for three weeks (Figure 1A), the plates were observed to have lost approximately 0.12 % weight. When anodized aluminum plates were exposed to an alkaline cleaning composition comprising ascorbic acid only for three weeks (Figure IB), the plates were observed to have lost approximately 0.09 % weight. When anodized aluminum plates were exposed to an alkaline cleaning composition comprising octyl phosphonic acid only (Figure 1C), the plates were observed to have lost approximately 0.11 % weight. However, when anodized aluminum plates
were exposed to an alkaline cleaning composition comprising both ascorbic acid and octyl phophonic acid (Figure ID), the plates were observed to lose approximately no weight.
Accordingly, the effect of combining ascorbic acid and a phosphonic acid provided a greater corrosion inhibition than the mere sum of the effect for each of ascorbic acid and the phosphonic acid individually, and therefore, it has been surprisingly shown that the combination of both ascorbic acid and a phosphonic acid provides much greater corrosion inhibition than expected from that observed for either one alone. - Immersion of anodized aluminum plates at 55 °C
The above procedure was followed with an elevated temperature of 55°C and results taken after 24 hours. 12cm by 6cm by 0.1cm anodized aluminum plates were weighed, and then immersed and suspended in a cleaning composition B diluted to 0.6% in deionised water for 24 hours.
The results are shown in Figure 2. The composition of cleaning composition B is shown in Table 2, and included an alkaline cleaning formula shown in Table 3, to which ascorbic acid (sourced from VWR) and octyl phosphonic acid (Rhodafac ASI 80, sourced from Solvay) were added. The final 0.6% solution was pH 12.
Table 2 - Cleaning composition B
Alkaline Cleaning formula
Sodium Hydroxide alkali source 1.82
Polyacrylic acid
sodium salt polymer complexing agent 0.32
Suface active
PEG 8000 polymer agent 0,10
Total 100.00
Table 3 - Alkaline Cleaning Formulation
Machine test of metal plates at 55 °C
Automatic processing of a red anodized aluminum, blue anodized aluminum, (both 12cm by 6cm by 0.1cm) aluminum (10cm by 5cm by 0.1cm), and brass (5cm by 5cm by 0.1cm) plates using a Miele 8528 instrument reprocessing machine was carried out to reproduce the effect that may be observed by machine processing of metal articles.
The metal plates were processed using four different cleaning compositions based upon the alkaline cleaning formulation of Table 3 and dosed to 0.6% with deionized water (~pH 11.3). The first cleaning composition comprised the alkaline cleaner only. The second cleaning composition comprised the alkaline cleaner and ascorbic acid. The third cleaning composition comprised the alkaline cleaner and the phosphonic acid only. The fourth cleaning composition comprised the alkaline cleaner, ascorbic acid and the phosphonic acid.
Table 4 -Cleaning composition C plus ascorbic acid and the phosphonic acid
Each cleaning composition was added to the machine and the metal plate to be tested placed in the machine for processing. The machine then processed the metal plate using
the composition and the resulting metal plate was weighed to determine the extent of corrosion from the weight lost from the metal plate.
The results are shown in Figures 3-6. As can be seen for blue anodized aluminum, red anodized aluminum, aluminum and brass, cleaning compositions comprising both ascorbic acid and phosphonic acid resulted in a greater reduction in weight loss of the metal plates than compositions with either ascorbic acid or phosphonic acid alone. Accordingly, the cleaning combination comprising both ascorbic acid and phosphonic acid are much more effective corrosion inhibitors than cleaning compositions with either ascorbic acid or phosphonic acid alone, or than might be expected by the additive effect of both ascorbic acid and the phosphonic acid together. Indeed, whilst compositions with ascorbic acid or phosphonic acid alone increased the weight loss of the brass plate compared to the cleaning composition alone, surprisingly, the combination of ascorbic acid and phosphonic acid resulted in a decrease in weight loss.
In further examples, the results of which are shown in Figure 7, the corrosion inhibiting properties of compositions D and E on blue anodized aluminum plates were investigated. Composition D (pH 11.3-11.4) comprised the alkaline cleaning composition of Table 3, triethanol amine, phosphonic acid, 2-ethylhexyl ester (sourced from Clariant), and/or ascorbic acid. The combination of the phosphoric acid ester and ascorbic acid again provided substantially increased corrosion inhibition when compared to the cleaning composition alone or comprising either ascorbic acid or the phosphoric acid ester alone.
Composition E (pH 11.4-11.5) comprised the alkaline cleaning composition of Table 3, tripolyphosphate and/or ascorbic acid. The combination of tripolyphosphate and ascorbic acid provided substantially increased corrosion inhibition when compared to the cleaning composition alone or comprising either ascorbic acid or tripolyphosphate alone.
All of the compositions and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. In addition, unless expressly stated to the
contrary, use of the term "a" is intended to include "at least one" or "one or more." For example, "a device" is intended to include "at least one device" or "one or more devices."
Any ranges given either in absolute terms or in approximate terms are intended to encompass both, and any definitions used herein are intended to be clarifying and not limiting. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges (including all fractional and whole values) subsumed therein.
Furthermore, the invention encompasses any and all possible combinations of some or all of the various embodiments described herein. It should also be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
Claims
1. An alkaline corrosion inhibitor composition comprising ascorbic acid or a salt thereof.
2. An alkaline corrosion inhibitor composition according to claim 1 further comprising at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt.
3. An alkaline corrosion inhibitor composition according to claim 2, wherein the at least one phosphonic acid comprises octyl phosphonic acid, and/or 2-carboxyethyl phosphonic acid, or a salt thereof.
4. An alkaline corrosion inhibitor composition according to either one of claim 2 or claim 3, wherein the at least one phosphoric acid ester comprises phosphoric acid, 2-ethylhexyl ester and/or phosphoric acid, mixed esters with butyl alcohol and ethylene glycol.
5. An alkaline corrosion inhibitor composition according to any of claims 2 to 4, wherein the at least one phosphate salt comprises tripolyphosphate.
6. An alkaline corrosion inhibitor composition according to any one of claims 2 to 5, wherein the ratio of the amount of ascorbic acid to the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt in the composition is approximately between 3:1 and 1:1.
7. An alkaline corrosion inhibitor a composition according to claim 6, wherein the ratio of the amount of ascorbic acid to the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt in the composition is approximately 2:1.
8. An alkaline cleaning composition comprising the corrosion inhibitor composition of any of claims 1 to 6.
9. An alkaline cleaning composition according to claim 8 further comprising at least one surfactant and/or polymer.
10. An alkaline cleaning composition according to either one of claims 8 or 9, wherein the cleaning composition has a pH greater than 8.5.
11. An alkaline cleaning composition according to claim 10, wherein the cleaning composition has a pH greater than 9.5.
12. An alkaline cleaning composition according to claim 11, wherein the cleaning composition has a pH greater than 11.0.
13. An alkaline cleaning composition according to any of claims 8 to 12 when dependent on claim 2, wherein the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is present in an amount ranging from about 0.1 to 5.0 weight %, and the ascorbic acid is present in an amount ranging from about 0.2 to 10.0 weight %.
14. An alkaline cleaning composition according to claim 13, wherein the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is present in an amount ranging from about 0.1 to 1.0 weight % and the ascorbic acid is present in an amount ranging from about 0.1 to 2.0 weight %.
15. An alkaline cleaning composition according to claim 14, wherein the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt is present in an amount of about 0.5 weight % and the ascorbic acid is present in an amount of about 1.0 weight %.
16. A method of mitigating corrosion of metallic articles during cleaning, the method comprising the steps:
(a) providing a metal article to be cleaned;
(b) providing an effective amount of the alkaline corrosion inhibitor according to any of claims 1 to 7;
(c) providing an alkaline cleaning composition;
(d) adding the alkaline corrosion inhibitor to the alkaline cleaning composition to produce an alkaline corrosion inhibiting cleaning composition; and
(e) cleaning the metal article with the alkaline corrosion inhibiting cleaning composition.
17. A method according to claim 16, wherein step (e) is carried out automatically.
18. A method according to claim 16, wherein step (e) is carried out manually.
19. A method according to any of claims 16 to 18, wherein an effective amount of corrosion inhibitor is such that the amount of the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt within the corrosion inhibiting cleaning composition ranges from about 0.1 to 5.0 weight %, and the amount of ascorbic acid within the corrosion inhibiting cleaning composition ranges from about 0.2 to 10.0 weight %.
20. A method according to claim 19, wherein an effective amount of corrosion inhibitor is such that the amount of the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt within the corrosion inhibiting cleaning composition ranges from about 0.1 to 1.0 weight %, and the amount of ascorbic acid within the corrosion inhibiting cleaning composition ranges from about 0.2 to 2.0 weight %.
21. A method according to claim 20, wherein an effective amount of corrosion inhibitor is such that the amount of the at least one phosphonic acid or a salt thereof, and/or at least one phosphoric acid ester or a salt thereof, and/or at least one phosphate salt within the corrosion inhibiting cleaning composition is about 0.5 weight % and the amount of ascorbic acid within the corrosion inhibiting cleaning composition is about 1.0 weight %.
22. A method according to any of claims 16 to 21, wherein the metallic articles are surgical instruments.
23. A method according to claim 22, wherein the surgical instruments are flexible endoscopes.
24. A method of mitigating corrosion of metallic articles during cleaning, the method comprising the steps:
(a) providing a metal article to be cleaned;
(b) providing an effective amount of the alkaline cleaning composition according to any of claims 8 to 15;
(c) cleaning the metal article with the alkaline cleaning composition.
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| GB201423165 | 2014-12-24 | ||
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| WO2008057380A1 (en) * | 2006-11-03 | 2008-05-15 | S. C. Johnson & Son, Inc. | Corrosion inhibitor system for mildly acidic to ph neutral halogen bleach-containing cleaning compositions |
| RU2010150939A (en) * | 2010-12-13 | 2012-06-20 | Открытое акционерное общество "Нижнекамскнефтехим" (RU) | CORROSION INHIBITOR |
| RU2519685C1 (en) * | 2013-05-06 | 2014-06-20 | Открытое акционерное общество "Химический завод им. Л.Я. Карпова" | Method of producing corrosion inhibitor |
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2015
- 2015-12-09 WO PCT/US2015/064593 patent/WO2016105941A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008057380A1 (en) * | 2006-11-03 | 2008-05-15 | S. C. Johnson & Son, Inc. | Corrosion inhibitor system for mildly acidic to ph neutral halogen bleach-containing cleaning compositions |
| RU2010150939A (en) * | 2010-12-13 | 2012-06-20 | Открытое акционерное общество "Нижнекамскнефтехим" (RU) | CORROSION INHIBITOR |
| RU2519685C1 (en) * | 2013-05-06 | 2014-06-20 | Открытое акционерное общество "Химический завод им. Л.Я. Карпова" | Method of producing corrosion inhibitor |
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