US3277011A - Corrosion restraining compositions - Google Patents
Corrosion restraining compositions Download PDFInfo
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- US3277011A US3277011A US385450A US38545064A US3277011A US 3277011 A US3277011 A US 3277011A US 385450 A US385450 A US 385450A US 38545064 A US38545064 A US 38545064A US 3277011 A US3277011 A US 3277011A
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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
- 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
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/04—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors
- C23G1/06—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors organic inhibitors
Definitions
- This invention relates to corrosion restraining compositions and more particularly it relates to liquid compositions for restraining the corrosion of ferrous metals in acid pickling baths.
- Ferrous metals such as steel, which are subjected to working at elevated temperatures during the course of manufacture become coated with a layer of oxide impurity, often referred to as mill scale.
- a layer of oxide impurity often referred to as mill scale.
- acid pickling an operation referred to as acid pickling.
- the acid commonly used for this purpose is sulphuric acid, although other acids such as hydrochloric acid, phosphoric acid and sulphamic acid may be used.
- a particularly valuable corrosion-restraining composition for acid pickling baths may be obtained from a mixture of di-n-butylthiourea, an amine/alkylene oxide condensate and a propylene glycol solvent.
- a corrosion restraining composition which comprises a mixture of 1 part by weight of di-n-butylthiourea and from 2 to 5 part-s by weight of an amine/alkylene oxide condensate as hereinafter defined incorporated with a propylene glycol solvent as hereinafter defined, the weight of the said solvent being from 1 to 4 times the weight of the said mixture.
- the amine/alkylene oxide condensates used in the corrosion restraining compositions of our invention are the condensates of 1 mol. of an aliphatic primary amine containing from 8 to 18 carbon atoms or of 1 mol. of a mixture of such amines with from 3 to 20 mols. of an alkylene oxide.
- the condensates are thus essentially tertiary amines having an aliphatic hydrocarbon radical of from 8 to 18 carbon atoms as one of the N-substituents and having as the remaining N-substituents two polyalkanoxy radicals, or are mixtures of such amines.
- the aliphatic primary amines from which the condensates are derived may have saturated or unsaturated hydrocarbon radicals which include, for example, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, octadecenyl, octadecadienyl and octadecatrienyl.
- Such aliphatic primary amines and mixtures of such amines may be derived, for example, from naturally occurring fatty glycerides such as coconut oil, soyabean oil and tallow, which contain mixtures of such saturated and unsaturated hydrocarbon radicals.
- the alkylene oxide from which the amine/alkylene oxide condensates are derived may be ethylene oxide or propylene oxide, but is preferably ethylene oxide.
- the amine/alkylene oxide condensates contain a substantial proportion of compounds which may be represented by the following formulaice in which R represents a saturated or unsaturated hydrocarbon radical of from 8 to 18 carbon atoms, n represents one of the integers 2 and 3, and p and q independently represent zero or a positive integer although the condensates are not restricted solely to compounds of this formula.
- the condensates are obtained by methods al' ready well known in themselves. Depending on the molecular size of the hydrocarbon radical of the amine and the number of mols. of alkylene oxide used in the prep aration, the condensates may or may not be soluble in water. We prefer that the condensates are soluble in water, but the invention is not limited to water-soluble condensates.
- a propylene glycol solvent we mean a monopropylene glycol, a dipropylene glycol, a tripropylene glycol or mixtures of two or more of these glycols. Particularly suitable are mixtures of a major proportion by weight of a dipropylene glycol with a minor proportion by weight of a monopropylene glycol.
- the corrosion restraining compositions of our invention are obtained from mixtures of 1 part by weight of di-n-butyl thiourea with from 2 to 5 parts by weight of the amine/alkylene oxide condensate. Particularly valuable are those compositions in which about 3 parts of amine/alkylene oxide condensate are used for each part of di-n-butylthiourea.
- the mixture is incorporated with from 1 to 4 times its weight of the propylene glycol solvent. Within these limits the proportion of the solvent to the mixture is not critical, and the formulation may be varied depending on the particular circumstances in which the corrosion restraining composition is to be used.
- the corrosion restraining compositions of our invention may be prepared by simple mixing of the components optionally followed by heating, for example, to 50 C. to ensure complete solution.
- compositions of our invention have the further advantage that they remain fluid and pourable down to quite low temperatures. This is particularly important since in some of the acid pickling plants in which corrosion restraining compositions are used it is not always possible to store them in heated conditions in cold weather.
- the compositions of our invention remain fluid and pourable at temperatures substantially below that of the freezing point of water, for example down to temperatures of 12 C. (10 F.).
- Our compositions also have the advantage that they induce foaming in acid-pickling baths, and so reduce acid spray.
- Example 1 A mixture of 10 parts of di-nbutylthiourea and 30 parts of the condensation product of a cocoarnine with 15 mols. of ethylene oxide was dissolved in 70 parts of dipropylene glycol.
- Example 2 A 40 cm. length of bright annealed mild steel strip, 6 mm. wide and 0.3 mm. thick, was immersed in 20% w./w. aqueous sulphuric acid containing 0.05% W./w. of the composition of Example 1 for 15 minutes at 95 C. and was found to have lost 0.0178 gram in weight. A similar mild steel strip treated under the same conditions with 20% w./w. aqueous sulphuric acid omitting the composition of Example 1 was found to have lost 1.7740 grams in weight.
- a corrosion restraining composition which consists essentially of a mixture of 1 part by weight of di-n-butylthiourea and from 2 to parts by weight of an amine/alkylene oxide condensate incorporated with a propylene glycol solvent selected from the class consisting of monopropylene glycol, dipropylene glycol, tripropylene glycol and mixtures of said glycols, the weight of said solvent being from 1 to 4 times the weight of the said mixture, and said amine/alkylene oxide condensate having the formula:
- R represents a radical selected from the class consisting of saturated and unsaturated hydrocarbon radicals containing from 8 to 18 carbon atoms, and the sum of p and q represents a number selected from 0 to 20.
- R represents a radical selected from the class consisting of saturated and unsaturated hydrocarbon radicals containing from 8 to 18 carbon atoms, and the sum of p and q represents a number selected from 0 to 20.
- a liquid corrosion restraining composition which consists essentially of a mixture of 10 parts of di-n-butylthiourea and 30 parts of the condensation product of 1 molecular proportion of a cocoamine with 15 molecular proportions of ethylene oxide dissolved in parts of dipropylene glycol.
- An acid pickling bath consisting of an aqueous pickling acid containing a corrosion restraining composition which comprises a mixture of 1 part by weight of di-nbutylthiourea and from 2 to 5 parts by weight of an amine/alkylene oxide condensate incorporated with a propylene glycol solvent selected from the class consisting of monopropylene glycol, dipropylene glycol, tripropylene glycol and mixtures of said glycols, the Weight of the said solvent being from 1 to 4 times the weight of the said mixture, said amine/alkylene oxide condensate having the following formula:
- R represents a radical selected from the class consisting of saturated and unsaturated hydrocarbon radicals containing from 8 to 18 carbon atoms, and the sum of p and q represents a number selected from 0 to 20.
- An acid pickling bath as claimed in claim 5 which contains between 0.03% and 0.5% of the corrosion restraining composition calculated on the weight of acid.
- An acid pickling bath as claimed in claim 5 in which the aqueous acid is 5% to 25% sulphuric acid.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Detergent Compositions (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Description
United States Tatent O 3 277 011 CORROSION RESTIiAII IING COMPOSITIONS Eric Milton Chadwick and Richard Stanley Moreton, Manchester, England, assignors to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain No Drawing. Filed July 27, 1964, Ser. No. 385,450 Claims priority, application Great Britain, Aug. 22, 1963, 33,303/ 63 8 Claims. (Cl. 252-149) This invention relates to corrosion restraining compositions and more particularly it relates to liquid compositions for restraining the corrosion of ferrous metals in acid pickling baths.
Ferrous metals, such as steel, which are subjected to working at elevated temperatures during the course of manufacture become coated with a layer of oxide impurity, often referred to as mill scale. For many subsequent processing operations, such as coating or plating, it is necessary to remove the layer of oxide scale, and it is usual to do this by treating the metal in a bath of aqueous acid, an operation referred to as acid pickling. The acid commonly used for this purpose is sulphuric acid, although other acids such as hydrochloric acid, phosphoric acid and sulphamic acid may be used. Once the layer of oxide scale is removed, the acid is free to attack the exposed metal surface and in order to reduce the attack on the metal itself as much as possible it is advantageous to add a corrosion restrainer to the acid pickling bath.
We have now found that a particularly valuable corrosion-restraining composition for acid pickling baths may be obtained from a mixture of di-n-butylthiourea, an amine/alkylene oxide condensate and a propylene glycol solvent.
Thus according to our invention we provide a corrosion restraining composition which comprises a mixture of 1 part by weight of di-n-butylthiourea and from 2 to 5 part-s by weight of an amine/alkylene oxide condensate as hereinafter defined incorporated with a propylene glycol solvent as hereinafter defined, the weight of the said solvent being from 1 to 4 times the weight of the said mixture.
The amine/alkylene oxide condensates used in the corrosion restraining compositions of our invention are the condensates of 1 mol. of an aliphatic primary amine containing from 8 to 18 carbon atoms or of 1 mol. of a mixture of such amines with from 3 to 20 mols. of an alkylene oxide. The condensates are thus essentially tertiary amines having an aliphatic hydrocarbon radical of from 8 to 18 carbon atoms as one of the N-substituents and having as the remaining N-substituents two polyalkanoxy radicals, or are mixtures of such amines. The aliphatic primary amines from which the condensates are derived may have saturated or unsaturated hydrocarbon radicals which include, for example, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, octadecenyl, octadecadienyl and octadecatrienyl. Such aliphatic primary amines and mixtures of such amines may be derived, for example, from naturally occurring fatty glycerides such as coconut oil, soyabean oil and tallow, which contain mixtures of such saturated and unsaturated hydrocarbon radicals.
The alkylene oxide from which the amine/alkylene oxide condensates are derived may be ethylene oxide or propylene oxide, but is preferably ethylene oxide. The amine/alkylene oxide condensates contain a substantial proportion of compounds which may be represented by the following formulaice in which R represents a saturated or unsaturated hydrocarbon radical of from 8 to 18 carbon atoms, n represents one of the integers 2 and 3, and p and q independently represent zero or a positive integer although the condensates are not restricted solely to compounds of this formula. The condensates are obtained by methods al' ready well known in themselves. Depending on the molecular size of the hydrocarbon radical of the amine and the number of mols. of alkylene oxide used in the prep aration, the condensates may or may not be soluble in water. We prefer that the condensates are soluble in water, but the invention is not limited to water-soluble condensates.
By a propylene glycol solvent we mean a monopropylene glycol, a dipropylene glycol, a tripropylene glycol or mixtures of two or more of these glycols. Particularly suitable are mixtures of a major proportion by weight of a dipropylene glycol with a minor proportion by weight of a monopropylene glycol.
The corrosion restraining compositions of our invention, as already defined, are obtained from mixtures of 1 part by weight of di-n-butyl thiourea with from 2 to 5 parts by weight of the amine/alkylene oxide condensate. Particularly valuable are those compositions in which about 3 parts of amine/alkylene oxide condensate are used for each part of di-n-butylthiourea. The mixture is incorporated with from 1 to 4 times its weight of the propylene glycol solvent. Within these limits the proportion of the solvent to the mixture is not critical, and the formulation may be varied depending on the particular circumstances in which the corrosion restraining composition is to be used.
The corrosion restraining compositions of our invention may be prepared by simple mixing of the components optionally followed by heating, for example, to 50 C. to ensure complete solution.
The corrosion restraining properties of thiourea and its derivatives are already well known, but the corrosion restraining compositions of our invention have very much better corrosion restraining properties than would be expected from the known properties of the individual components. Moreover, our compositions have other advantages over corrosion inhibiting compositons used hitherto. Thus our compositions are liquid and when they are added to acid pickling baths they readily become emulsified and evenly distributed throughout the bath so that the maximum effect is obtained with a minimum usage of agent. The amount of the composition which is added to the acid pickling bath may be varied over wide limits but we prefer to add between 0.03% and 0.5% of the composition calculated on the weight of acid. Thus in the case of sulphuric acid we prefer to add between 0.5 lb. and 8 lbs. of the composition to 1 ton of 76% sulphuric acid (B.O.V.). This acid can then be diluted to any strength required, usually to between 5% and 25% sulphuric acid before use as a pickling medium. The compositions of our invention have the further advantage that they remain fluid and pourable down to quite low temperatures. This is particularly important since in some of the acid pickling plants in which corrosion restraining compositions are used it is not always possible to store them in heated conditions in cold weather. The compositions of our invention remain fluid and pourable at temperatures substantially below that of the freezing point of water, for example down to temperatures of 12 C. (10 F.). Our compositions also have the advantage that they induce foaming in acid-pickling baths, and so reduce acid spray.
The invention is illustrated but not limited by the following examples in which the parts and percentages are by weight.
Example 1 A mixture of 10 parts of di-nbutylthiourea and 30 parts of the condensation product of a cocoarnine with 15 mols. of ethylene oxide was dissolved in 70 parts of dipropylene glycol.
Example 2 A 40 cm. length of bright annealed mild steel strip, 6 mm. wide and 0.3 mm. thick, was immersed in 20% w./w. aqueous sulphuric acid containing 0.05% W./w. of the composition of Example 1 for 15 minutes at 95 C. and was found to have lost 0.0178 gram in weight. A similar mild steel strip treated under the same conditions with 20% w./w. aqueous sulphuric acid omitting the composition of Example 1 was found to have lost 1.7740 grams in weight.
What we claim is:
1. A corrosion restraining composition which consists essentially of a mixture of 1 part by weight of di-n-butylthiourea and from 2 to parts by weight of an amine/alkylene oxide condensate incorporated with a propylene glycol solvent selected from the class consisting of monopropylene glycol, dipropylene glycol, tripropylene glycol and mixtures of said glycols, the weight of said solvent being from 1 to 4 times the weight of the said mixture, and said amine/alkylene oxide condensate having the formula:
in which R represents a radical selected from the class consisting of saturated and unsaturated hydrocarbon radicals containing from 8 to 18 carbon atoms, and the sum of p and q represents a number selected from 0 to 20. 2. A composition as claimed in claim 1 which contains about 3 parts by weight of said amine/alkylene oxide condensate for each part of di-n-butylthiourea.
- 3. A composition as claimed in claim 1 in which the amine/alkylene oxide condensate is the condensate of 1 molecular proportion of aliphatic primary amine containing from 8 to 18 carbon atoms in each molecule with from 3 to 20 molecular proportions of ethylene oxide.
4. A liquid corrosion restraining composition which consists essentially of a mixture of 10 parts of di-n-butylthiourea and 30 parts of the condensation product of 1 molecular proportion of a cocoamine with 15 molecular proportions of ethylene oxide dissolved in parts of dipropylene glycol.
5. An acid pickling bath consisting of an aqueous pickling acid containing a corrosion restraining composition which comprises a mixture of 1 part by weight of di-nbutylthiourea and from 2 to 5 parts by weight of an amine/alkylene oxide condensate incorporated with a propylene glycol solvent selected from the class consisting of monopropylene glycol, dipropylene glycol, tripropylene glycol and mixtures of said glycols, the Weight of the said solvent being from 1 to 4 times the weight of the said mixture, said amine/alkylene oxide condensate having the following formula:
in which R represents a radical selected from the class consisting of saturated and unsaturated hydrocarbon radicals containing from 8 to 18 carbon atoms, and the sum of p and q represents a number selected from 0 to 20.
6. An acid pickling bath as claimed in claim 5 which contains between 0.03% and 0.5% of the corrosion restraining composition calculated on the weight of acid.
7. An acid pickling bath as claimed in claim 5 in which the aqueous acid is 5% to 25% sulphuric acid.
8. An acid pickling bath as claimed in claim 7 wherein the corrosion restraining composition is presented in a proportion of from 0.5 lb. to 8 lbs. of the said composition to 1,520 lbs. of sulphuric acid.
References Cited by the Examiner UNITED STATES PATENTS 1,797,401 3/1931 Calcott et al. 25239l FOREIGN PATENTS 923,865 4/1963 Great Britain.
OTHER REFERENCES Armour Ethoxylated Chemicals, Armour Industrial Chemical Company, April 1963, page 17.
LEON D. ROSDOL, Primary Examiner.
JULIUS GREENWALD, Examiner.
S. E. DARDEN, Assistant Examiner.
Claims (1)
1. A CORROSION RESTRAINING COMPOSITION WHICH CONSISTS ESSENTIALLY OF A MIXTURE OF 1 PART BY WEIGHT OF DI-N-BUTYLTHIOUREA AND FROM 2 TO 5 PARTS BY WEIGHT OF AN AMINE/ALKYLENE OXIDE CONDENSATE INCORPORATED WITH A PROPYLENE GLYCOL SOLVENT SELECTED FROM THE CLASS CONSISTING OF MONOPROPYLENE GLYCOL, DIPROPYLENE GLYCOL, TRIPROPYLENE GLYCOL AND MIXTURE OF SAID GLYCOLS, THE WEIGHT OF SAID SOLVENT BEING FROM 1 TO 4 TIMES THE WEIGHT OF SAID MIXTURE AND SAID AMINE/ALKYLENE OXIDE CONDENSATE HAVING THE FORMULA
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB33303/63A GB1010753A (en) | 1963-08-22 | 1963-08-22 | Corrosion restraining compositions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3277011A true US3277011A (en) | 1966-10-04 |
Family
ID=10351197
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US385450A Expired - Lifetime US3277011A (en) | 1963-08-22 | 1964-07-27 | Corrosion restraining compositions |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US3277011A (en) |
| BE (1) | BE651880A (en) |
| DE (1) | DE1521790B2 (en) |
| DK (1) | DK128660B (en) |
| GB (1) | GB1010753A (en) |
| NL (1) | NL6409242A (en) |
| SE (1) | SE315782B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3466192A (en) * | 1967-01-23 | 1969-09-09 | Amchem Prod | Corrosion prevention process |
| US4381249A (en) * | 1979-05-14 | 1983-04-26 | Bouffard Joseph O | Rust removing and metal surface protecting composition |
| US4557838A (en) * | 1982-04-08 | 1985-12-10 | Air Products And Chemicals, Inc. | Inhibiting acid corrosion of metals |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4514320A (en) * | 1980-10-27 | 1985-04-30 | Petrolite Corporation | Halide free corrosion inhibitors |
| US4539140A (en) * | 1980-10-27 | 1985-09-03 | Petrolite Corporation | Mixtures of non-halogen salts of nitrogen heterocyclics and nitrogen-sulfur heterocyclics |
| US4525296A (en) * | 1980-10-27 | 1985-06-25 | Petrolite Corporation | Halide free corrosion inhibitors |
| US4559163A (en) * | 1980-10-27 | 1985-12-17 | Petrolite Corporation | Halide free octahydrophenanthridine corrosion inhibitors |
| DE4244245A1 (en) * | 1992-12-24 | 1994-06-30 | Norsk Hydro Chemtech Gmbh | Use of easily removable inhibitors in pickling acids |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1797401A (en) * | 1931-03-24 | And herbert w | ||
| GB923865A (en) * | 1960-06-13 | 1963-04-18 | Union Chimique Belge Sa | Pickling inhibitor compositions |
-
1963
- 1963-08-22 GB GB33303/63A patent/GB1010753A/en not_active Expired
-
1964
- 1964-07-27 US US385450A patent/US3277011A/en not_active Expired - Lifetime
- 1964-08-04 DK DK385564A patent/DK128660B/en unknown
- 1964-08-11 NL NL6409242A patent/NL6409242A/xx unknown
- 1964-08-14 BE BE651880A patent/BE651880A/xx unknown
- 1964-08-21 DE DE19641521790 patent/DE1521790B2/en not_active Withdrawn
- 1964-08-21 SE SE10135/64A patent/SE315782B/xx unknown
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1797401A (en) * | 1931-03-24 | And herbert w | ||
| GB923865A (en) * | 1960-06-13 | 1963-04-18 | Union Chimique Belge Sa | Pickling inhibitor compositions |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3466192A (en) * | 1967-01-23 | 1969-09-09 | Amchem Prod | Corrosion prevention process |
| US4381249A (en) * | 1979-05-14 | 1983-04-26 | Bouffard Joseph O | Rust removing and metal surface protecting composition |
| US4557838A (en) * | 1982-04-08 | 1985-12-10 | Air Products And Chemicals, Inc. | Inhibiting acid corrosion of metals |
Also Published As
| Publication number | Publication date |
|---|---|
| DE1521790B2 (en) | 1971-03-25 |
| NL6409242A (en) | 1965-02-23 |
| GB1010753A (en) | 1965-11-24 |
| DK128660B (en) | 1974-06-10 |
| DE1521790A1 (en) | 1970-08-13 |
| BE651880A (en) | 1965-02-15 |
| SE315782B (en) | 1969-10-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: ABM CHEMICALS LIMITED, UNITY MILL. POLEACRE LANE, Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:IMPERIAL CHEMICAL INDUSTRIES LIMITED,;REEL/FRAME:003848/0731 Effective date: 19810401 |