CA1139543A - Corrosion inhibitors, method of producing them and protective coatings containing them - Google Patents
Corrosion inhibitors, method of producing them and protective coatings containing themInfo
- Publication number
- CA1139543A CA1139543A CA000365509A CA365509A CA1139543A CA 1139543 A CA1139543 A CA 1139543A CA 000365509 A CA000365509 A CA 000365509A CA 365509 A CA365509 A CA 365509A CA 1139543 A CA1139543 A CA 1139543A
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- Canada
- Prior art keywords
- anions
- particles
- corrosion inhibiting
- corrosion
- alumina
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
CORROSION INHIBITORS, METHOD OF PRODUCING
THEM AND PROTECTIVE COATINGS CONTAINING THEM
Corrosion inhibiting particles comprise an inorganic oxide, particularly alumina, having corrosion inhibiting anions, particularly phosphate, chromate or benzoate anions, chemically bound to them. They may be prepared by contacting an oxide containing hydroxyl groups with an acidic solution containing the anions at ambient temperatures.
The particles may be incorporated into protective coatings, e.g.
paints based on epoxy resins, alkyd resins or chlorinated rubbers, in amounts up to 80% wt based on dry film weight, giving coatings with up to 4.0% corrosion inhibiting anions.
Release of the anions is by ion-exchange with other anions, e.g.
the chloride anions of sea water or salt spray, and does not, as is normal with corrosion inhibiting coatings, depend on water solubility.
CORROSION INHIBITORS, METHOD OF PRODUCING
THEM AND PROTECTIVE COATINGS CONTAINING THEM
Corrosion inhibiting particles comprise an inorganic oxide, particularly alumina, having corrosion inhibiting anions, particularly phosphate, chromate or benzoate anions, chemically bound to them. They may be prepared by contacting an oxide containing hydroxyl groups with an acidic solution containing the anions at ambient temperatures.
The particles may be incorporated into protective coatings, e.g.
paints based on epoxy resins, alkyd resins or chlorinated rubbers, in amounts up to 80% wt based on dry film weight, giving coatings with up to 4.0% corrosion inhibiting anions.
Release of the anions is by ion-exchange with other anions, e.g.
the chloride anions of sea water or salt spray, and does not, as is normal with corrosion inhibiting coatings, depend on water solubility.
Description
~736 CORROSION INHIBITORS, METHOD OF PRODUCING
~HEM AND PROTECTIVE COATINGS CONTAINING THEM
This invention relates to corrosion inhibitors suitable for incorporation into protective coatings, e.g. paints.
It is well known that certain anions, e.g. phosphate, chromate and benzoate anions have corrosion inhibiting properties and that compounds containing such species can be included in protective coatings. The compounds are usually in the form of sparingly water-soluble salts. The coatings themselves have a limited permeability to water and it is believed that the mechanism of corrosion inhibition involves the gradual dissolving of the compounds in water releasing the anions as the active inhibitors. For such systems to be effective over a long perlod the solubiIity of the compound is particularly ~; important. If the compound~ e soluble, blistering of the coating may occur and the compound will be rapidly depleted; if it is insufficiently soluble the compound will be ineffective.
The present invention is concerned with corrosion inhibitors which depend for their effectiveness on ion exchange rather than solubility.
According to the present invention, a corrosion inhibitor comprises particles of an inorganic oxide having corrosion inhibiting anions chemically bound to the particles.
The preferred corrosion inhibiting anions are those mentioned above, i.e. phosphate, chromate and benzoate anions but other known corrosion inhibiting anions may also be used provided, as discussed hereafter, they are stable in acid media.
The preferred inorganic oxide is alumina. Other oxides which may .
be suitable include zirconia, iron oxides (Fe2O3 and Fe3O4), and tin .
oxide. Mixed metal oxides may also be suitable as may naturally occurring clays such as kaolinite. As is well known, particles of aiumina and other oxides may be prepared which have a proportion of hydroxyl groups on their surface, e.g. the so-called activated aluminas of commerce used, inter alia, as packing for chromatographic columns.
It has been found that the hydroxyl groups can be replaced by contacting the oxide (e.g. alumil!a) with an acidic solution containing phosphate, chromate or benzoate anions. Th~ u~take of "~r~ anions tends to increase as the pH is decreased below p~, and at 8 relatively low pH, (e.g. a pH of from 2 to 5), uptake will occur at ambient temperature relatively quickly (contact time of, for example, up to 5 hours). Elevated temperatures are not damaging, however, and may be used if required, e.g. with benzoic acid to increase its solubility in water. The uptake of anions on the oxide can be ~ teC,~ ,. ;y~- es measured by standard analytical-e~d~si~a~, e.g. x-ray fluoresence for phosphate or chromate anions, and carbon analysis for benzoate anions. The mini~um uptake will depend on the proportion of replaceable hydroxyl groups and, clearly, oxides with a high proportion of such groups are preferred. Examples of suitable aluminas are the commercially available activated aluminas sold under the name "Camag' and defined as having a ~rockman Activity I
for chromatography, and Fl aluminas sold by the Aluminium Company of America.
Depending on the proportion of hydroxyl groups on the inorganic oxide it has been found that up to 5% wt of anion can be combined with the oxide ~i.e. up to 0.7 millimoles/g). Since, as indicated above, the technique of ion-exchange i~ relatively simple the selection of preferred inorganic oxides and the treatments to give maximum uptake of corrosion inhibiting anions can be determined by simple comparative experiments. The preferred lower limit is 1% wt.
The corrosion inhibiting particles may be included in protective coatings and the present invention includes protective coatings containing corrosion inhibiting particles as described above. The protective coating may be any of the known types of protective coaeings based on film forming polymers or resins, e.g. paints, ~'90~
.r;t ~ r~, varnishes and lacquer3. It may, in particular, be primer paints based on-e~ r~slns, vinyl resins, alkyd resins or chlorinated ~ubb~
The corrosion inhibiting particles may act as a filler for the coating and may be included in relatively large amount of up -to 40~ wt., based on the composition to be applied and up to 80% wt. based on the dry film weight.
Having re~ard to the quantity of anions which can be combined with the oxide as discussed previously it will be seen that the coatings may contain up to 4~ wt. of corrosion-inhibiting anions based on the dry film weight.
Preferably the quantity of corrosion-inhihiting anions is at the upper end of the range, preferred amounts of particles being 30-30% wt. based on the dry film weight giving from 1.5 up to 4.0% wt. of corrosion inhibiting anions.
When used in protective coatings the particles should be suitably small so as to remain in suspension in the composition before application and so as not to substan-tially affect the ease of application or the smoothness of the dry coating. Suitable particles sizes may be up to 100 micron diameter.
The corrosion inhibiting particles act to release the anion into solution by ion exchange with an anion which exists in the environment in which the particles are used.
Thus the invention is particularly useful for protecting structures in or above the sea, the sea providing chloride anions for exchange with the corrosion inhibiting anions.
The structures will normally be metal structuxes and the cor-rosion inhibiting particles will normally be in a protective coating. Unlike present paints which act by the solubili-zation of corrosion inhibiting salts, it is the permeability to the exchanging anions rather than the permeability of water which controls the rate of release of the corrosion inhibiting ions. Thus the corxosion inhibiting anions will be preferentially released from the alumina in those areas where the desired barrier properties of the coating are weak-est.
Particular structures which may be protected are the hulls and superstructures of ships, and rigs and platforms used for oil or gas exploration or production.
The invention may, however, have application for protecting structures on land where potentially corrosive anions may be present in the atmosphere, e.g. structures subject to atmospheres with relatively high concentrations of S02, S03 or Cl .
In addition to control of the release of the corrosion inhibiting anions by control of the ion permeability of the protective coating, control may also be exercised by the typP of anion and the type of oxide.
Thus, in otherwise identical conditions, it has been folmd that phosphate anions are released less easily than chromate anions which, in their turn, are released less easily than benzoate anions.
There may also be differences in the rate of release as between different types of alumina.
The invention is illustrated by the following examples.
Example 1 Preparation of ion-exchanged aluminas The aluminas used were activated aluminas sold under the designations Fl by the Aluminium Company of America and "CAMAG"
M.F.C. Brockmann Activity 1 (Neutral) by Hopkin and Williams.
The same treatment was given to both aluminas. The Fl alumina was in the form of 14-28 mesh granules and the "CAMAG" alumina was also in similar granular form. Chromate, phosphate and ben~oate anions were combined with the aluminas as follows:-1. 500 g of the activated alumina were treated with 1 litre of 25 an aqueous solution of 40g R2CrO4 at 25C. Concentrated nitric acid (approximately 40 ml) was added to give a pH of 3.5 after 2 hours stirring. The alumina was then separated on a sieve and washed thoroughly with distilled water.
~HEM AND PROTECTIVE COATINGS CONTAINING THEM
This invention relates to corrosion inhibitors suitable for incorporation into protective coatings, e.g. paints.
It is well known that certain anions, e.g. phosphate, chromate and benzoate anions have corrosion inhibiting properties and that compounds containing such species can be included in protective coatings. The compounds are usually in the form of sparingly water-soluble salts. The coatings themselves have a limited permeability to water and it is believed that the mechanism of corrosion inhibition involves the gradual dissolving of the compounds in water releasing the anions as the active inhibitors. For such systems to be effective over a long perlod the solubiIity of the compound is particularly ~; important. If the compound~ e soluble, blistering of the coating may occur and the compound will be rapidly depleted; if it is insufficiently soluble the compound will be ineffective.
The present invention is concerned with corrosion inhibitors which depend for their effectiveness on ion exchange rather than solubility.
According to the present invention, a corrosion inhibitor comprises particles of an inorganic oxide having corrosion inhibiting anions chemically bound to the particles.
The preferred corrosion inhibiting anions are those mentioned above, i.e. phosphate, chromate and benzoate anions but other known corrosion inhibiting anions may also be used provided, as discussed hereafter, they are stable in acid media.
The preferred inorganic oxide is alumina. Other oxides which may .
be suitable include zirconia, iron oxides (Fe2O3 and Fe3O4), and tin .
oxide. Mixed metal oxides may also be suitable as may naturally occurring clays such as kaolinite. As is well known, particles of aiumina and other oxides may be prepared which have a proportion of hydroxyl groups on their surface, e.g. the so-called activated aluminas of commerce used, inter alia, as packing for chromatographic columns.
It has been found that the hydroxyl groups can be replaced by contacting the oxide (e.g. alumil!a) with an acidic solution containing phosphate, chromate or benzoate anions. Th~ u~take of "~r~ anions tends to increase as the pH is decreased below p~, and at 8 relatively low pH, (e.g. a pH of from 2 to 5), uptake will occur at ambient temperature relatively quickly (contact time of, for example, up to 5 hours). Elevated temperatures are not damaging, however, and may be used if required, e.g. with benzoic acid to increase its solubility in water. The uptake of anions on the oxide can be ~ teC,~ ,. ;y~- es measured by standard analytical-e~d~si~a~, e.g. x-ray fluoresence for phosphate or chromate anions, and carbon analysis for benzoate anions. The mini~um uptake will depend on the proportion of replaceable hydroxyl groups and, clearly, oxides with a high proportion of such groups are preferred. Examples of suitable aluminas are the commercially available activated aluminas sold under the name "Camag' and defined as having a ~rockman Activity I
for chromatography, and Fl aluminas sold by the Aluminium Company of America.
Depending on the proportion of hydroxyl groups on the inorganic oxide it has been found that up to 5% wt of anion can be combined with the oxide ~i.e. up to 0.7 millimoles/g). Since, as indicated above, the technique of ion-exchange i~ relatively simple the selection of preferred inorganic oxides and the treatments to give maximum uptake of corrosion inhibiting anions can be determined by simple comparative experiments. The preferred lower limit is 1% wt.
The corrosion inhibiting particles may be included in protective coatings and the present invention includes protective coatings containing corrosion inhibiting particles as described above. The protective coating may be any of the known types of protective coaeings based on film forming polymers or resins, e.g. paints, ~'90~
.r;t ~ r~, varnishes and lacquer3. It may, in particular, be primer paints based on-e~ r~slns, vinyl resins, alkyd resins or chlorinated ~ubb~
The corrosion inhibiting particles may act as a filler for the coating and may be included in relatively large amount of up -to 40~ wt., based on the composition to be applied and up to 80% wt. based on the dry film weight.
Having re~ard to the quantity of anions which can be combined with the oxide as discussed previously it will be seen that the coatings may contain up to 4~ wt. of corrosion-inhibiting anions based on the dry film weight.
Preferably the quantity of corrosion-inhihiting anions is at the upper end of the range, preferred amounts of particles being 30-30% wt. based on the dry film weight giving from 1.5 up to 4.0% wt. of corrosion inhibiting anions.
When used in protective coatings the particles should be suitably small so as to remain in suspension in the composition before application and so as not to substan-tially affect the ease of application or the smoothness of the dry coating. Suitable particles sizes may be up to 100 micron diameter.
The corrosion inhibiting particles act to release the anion into solution by ion exchange with an anion which exists in the environment in which the particles are used.
Thus the invention is particularly useful for protecting structures in or above the sea, the sea providing chloride anions for exchange with the corrosion inhibiting anions.
The structures will normally be metal structuxes and the cor-rosion inhibiting particles will normally be in a protective coating. Unlike present paints which act by the solubili-zation of corrosion inhibiting salts, it is the permeability to the exchanging anions rather than the permeability of water which controls the rate of release of the corrosion inhibiting ions. Thus the corxosion inhibiting anions will be preferentially released from the alumina in those areas where the desired barrier properties of the coating are weak-est.
Particular structures which may be protected are the hulls and superstructures of ships, and rigs and platforms used for oil or gas exploration or production.
The invention may, however, have application for protecting structures on land where potentially corrosive anions may be present in the atmosphere, e.g. structures subject to atmospheres with relatively high concentrations of S02, S03 or Cl .
In addition to control of the release of the corrosion inhibiting anions by control of the ion permeability of the protective coating, control may also be exercised by the typP of anion and the type of oxide.
Thus, in otherwise identical conditions, it has been folmd that phosphate anions are released less easily than chromate anions which, in their turn, are released less easily than benzoate anions.
There may also be differences in the rate of release as between different types of alumina.
The invention is illustrated by the following examples.
Example 1 Preparation of ion-exchanged aluminas The aluminas used were activated aluminas sold under the designations Fl by the Aluminium Company of America and "CAMAG"
M.F.C. Brockmann Activity 1 (Neutral) by Hopkin and Williams.
The same treatment was given to both aluminas. The Fl alumina was in the form of 14-28 mesh granules and the "CAMAG" alumina was also in similar granular form. Chromate, phosphate and ben~oate anions were combined with the aluminas as follows:-1. 500 g of the activated alumina were treated with 1 litre of 25 an aqueous solution of 40g R2CrO4 at 25C. Concentrated nitric acid (approximately 40 ml) was added to give a pH of 3.5 after 2 hours stirring. The alumina was then separated on a sieve and washed thoroughly with distilled water.
2. 500 g of the activated alumina were treated with 1 litre of 30 water and approximately 50 ml orthophosphoric acid (90%) at 25C
to give a pH of 3.2 after 3 hours stirring. The alumina was then separated on a sieve and washed thoroughly with dist;lled water.
to give a pH of 3.2 after 3 hours stirring. The alumina was then separated on a sieve and washed thoroughly with dist;lled water.
3. 500g of the activated alumina were treated with 1 litre of a 70:30 water:isopropanol solution containing 42g benzoic acid for 2 hours at 25C. The alumina was then separated on a sieve and washed thoroughly, first with 70:30 water:isopropanol and finally with distilled water.
4. The alumina used as a control was simply washed thoroughly with distilled water.
The amounts of anion incorporated by these treatments were 0.3 mmole/g chromate, 0.7 mmole/g phosphate and 0.4 m~ole/g benzoate for the Fl alumina. For the "CAMAG" alumina the figures were 0.2 mmole/g chromate and 0.6 mmole/g phosphate. The benzoate anion content was not measured but was predicted to be 0.3 mmole/g.
Example 2 Preparation and testing of paints The chromate exchanged "CAMAG" aLu~ina of Example 1, which had a maxi~um particle size of 100 micron (after dry grinding in a porcelain ball mill for 9 hours), was incorporated into a paint by ball milling for 15 minutes. Untreated alumina was also incorporated, in the same amount, into another sample of the same paint as control.
The composition of the paint was:
"~lloprene" R1015 g "Cereclor" 70 10 g "Cereclor'~ 42 5 g Alumina 30 g Xylene 25 g White Spirit 6 g Alloprene R10 is a chlorinated rubber sold by ICI Limited. Cereclor~
70 and 42 are chlorinated paraffins sold by ICI Limited.
Paints 2a (chromate exchanged alumina) and 2b (un-exchanged alumina), were applied by brush to polished mild steel pla~es (15cm x lOcm size) at a thickness of 80 microns. When dry, each paint film was scored through to the metal with diagonal lines and each paint tested by immersing the plates in salt water for 384 hours and by placing the plates in a salt spray cabinet conforming to ASTM B117/73 for 360 hours.
After testing each paint film was assessed visually for corrosion using a scale from 1 (= little corrosion) to 5 (= severe corrosion). The results are shown in Table 1 below.
~ ?'~ ~ ~ k Table 1 __ _ .
PaintSalt water Salt spray immersion 2b_ _ _ It will be seen that the paint containing chromate anions had better corrosion inhibiting properties than the paint containing unexchanged alumina.
Example 3 Chromate, phosphate, benzoate and unexchanged Fl aluminas prepared as described in Example 1 were prepared for incorporation into paints by grinding in distilled water in a porcelain ball mill for 60 hours and drying for 16 hours at 100C under vacuum The maximum particle size was 10 ~m. The ground particles were incorporated into paints by ball milling for 16 hours. The composition of the paints was-"Synolac 76W" ~ 30 g 36% Lead Octoate 0.25 g 12% Cobalt Octoate 0.75 g "Nuodex Exkin" 2 0.15 g Soya Lecithin0.04 g Alumina (each of samples a to d) 21.1 g "Microdol" Extra* 7.2 g White Spirit 5.0 g Synolac 76W is a long-oil alkyd solution in white spirit sold by Cray Valley Products Ltd. The lead and cobalt octoates are driers sold by Manchem Ltd. Nuodex Exkin 2 is an anti-skinning agent sold by Durham Raw Materials Ltd. Soya Lecithin is a pig~ent dispersant sold by BOCM Silcock. Microdol Extra is a micronised talc sold by A/S Norwegian Talc.
Paints 3a (chromate exchanged alumina), 3b (phosphate exchanged alumina), 3c (benzoate exchanged alumina) and 3d (unexchanged alumina), were brush-applied to polished mild steel plates (15cm x lOcm size) at a thickness of approximately 35 ~m. The plates were D ~ Yf~
3~5~
allowed to dry for one week at room temperature before testing by placing the plates in a salt spray cabinet (conforming to ASTM Bl17-73) for 336 hours.
After testing each plate was assessed visually for corrosion as in example 2. The results are sho~m in Table 2 below:
Table 2 Paint Salt Spray 3a 3b 2 3d 5 It will be seen that the paints containing ion exchanged alumina had better corrosion inhibiting properties than the paints containing unexchanged alumina.
The amounts of anion incorporated by these treatments were 0.3 mmole/g chromate, 0.7 mmole/g phosphate and 0.4 m~ole/g benzoate for the Fl alumina. For the "CAMAG" alumina the figures were 0.2 mmole/g chromate and 0.6 mmole/g phosphate. The benzoate anion content was not measured but was predicted to be 0.3 mmole/g.
Example 2 Preparation and testing of paints The chromate exchanged "CAMAG" aLu~ina of Example 1, which had a maxi~um particle size of 100 micron (after dry grinding in a porcelain ball mill for 9 hours), was incorporated into a paint by ball milling for 15 minutes. Untreated alumina was also incorporated, in the same amount, into another sample of the same paint as control.
The composition of the paint was:
"~lloprene" R1015 g "Cereclor" 70 10 g "Cereclor'~ 42 5 g Alumina 30 g Xylene 25 g White Spirit 6 g Alloprene R10 is a chlorinated rubber sold by ICI Limited. Cereclor~
70 and 42 are chlorinated paraffins sold by ICI Limited.
Paints 2a (chromate exchanged alumina) and 2b (un-exchanged alumina), were applied by brush to polished mild steel pla~es (15cm x lOcm size) at a thickness of 80 microns. When dry, each paint film was scored through to the metal with diagonal lines and each paint tested by immersing the plates in salt water for 384 hours and by placing the plates in a salt spray cabinet conforming to ASTM B117/73 for 360 hours.
After testing each paint film was assessed visually for corrosion using a scale from 1 (= little corrosion) to 5 (= severe corrosion). The results are shown in Table 1 below.
~ ?'~ ~ ~ k Table 1 __ _ .
PaintSalt water Salt spray immersion 2b_ _ _ It will be seen that the paint containing chromate anions had better corrosion inhibiting properties than the paint containing unexchanged alumina.
Example 3 Chromate, phosphate, benzoate and unexchanged Fl aluminas prepared as described in Example 1 were prepared for incorporation into paints by grinding in distilled water in a porcelain ball mill for 60 hours and drying for 16 hours at 100C under vacuum The maximum particle size was 10 ~m. The ground particles were incorporated into paints by ball milling for 16 hours. The composition of the paints was-"Synolac 76W" ~ 30 g 36% Lead Octoate 0.25 g 12% Cobalt Octoate 0.75 g "Nuodex Exkin" 2 0.15 g Soya Lecithin0.04 g Alumina (each of samples a to d) 21.1 g "Microdol" Extra* 7.2 g White Spirit 5.0 g Synolac 76W is a long-oil alkyd solution in white spirit sold by Cray Valley Products Ltd. The lead and cobalt octoates are driers sold by Manchem Ltd. Nuodex Exkin 2 is an anti-skinning agent sold by Durham Raw Materials Ltd. Soya Lecithin is a pig~ent dispersant sold by BOCM Silcock. Microdol Extra is a micronised talc sold by A/S Norwegian Talc.
Paints 3a (chromate exchanged alumina), 3b (phosphate exchanged alumina), 3c (benzoate exchanged alumina) and 3d (unexchanged alumina), were brush-applied to polished mild steel plates (15cm x lOcm size) at a thickness of approximately 35 ~m. The plates were D ~ Yf~
3~5~
allowed to dry for one week at room temperature before testing by placing the plates in a salt spray cabinet (conforming to ASTM Bl17-73) for 336 hours.
After testing each plate was assessed visually for corrosion as in example 2. The results are sho~m in Table 2 below:
Table 2 Paint Salt Spray 3a 3b 2 3d 5 It will be seen that the paints containing ion exchanged alumina had better corrosion inhibiting properties than the paints containing unexchanged alumina.
Claims (10)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A corrosion inhibitor comprising particles of an inorganic oxide having corrosion inhibiting anions, selected from the group comprising phosphate, chromate or benzoate, chemically bound to the particles by ion exchange, whereby the anions bound to the particles can only be released by further ion exchange.
2. A corrosion inhibitor as claimed in Claim 1 characterised in that the inorganic oxide is alumina.
3. A corrosion inhibitor as claimed in Claim 1, characterised in that the particles contain 1 to 5% by weight of corrosion inhibiting anions.
4. A corrosion inhibitor as claimed in Claim 1 characterised in that the particles are up to 100 micron in diameter.
5. A method of forming corrosion inhibiting particles as claimed in Claim 1 characterised in that an inorganic oxide containing hydroxyl groups is contacted with an acidic solution containing phosphate, chromate or benzoate anions at ambient temperature.
6. A method as claimed in Claim 5, wherein the pH of the acidic solution is from 2 to 5.
7. A protective coating containing corrosion inhibiting particles as claimed in Claim 1.
8. A protective coating as claimed in Claim 7, characterised in that it contains up to 80% wt. of particles based on the dry film weight.
9. A protective coating as claimed in Claim 8, containing 30 to 80% wt.
of particles based on the dry film weight.
of particles based on the dry film weight.
10. A protective coating as claimed in Claim 7, characterised in that the coating is based on an epoxy resin, vinyl resin, alkyd resin or chlorinated rubber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000365509A CA1139543A (en) | 1980-11-26 | 1980-11-26 | Corrosion inhibitors, method of producing them and protective coatings containing them |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000365509A CA1139543A (en) | 1980-11-26 | 1980-11-26 | Corrosion inhibitors, method of producing them and protective coatings containing them |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1139543A true CA1139543A (en) | 1983-01-18 |
Family
ID=4118554
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000365509A Expired CA1139543A (en) | 1980-11-26 | 1980-11-26 | Corrosion inhibitors, method of producing them and protective coatings containing them |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1139543A (en) |
-
1980
- 1980-11-26 CA CA000365509A patent/CA1139543A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |