Title of Invention

"RUST REFORMING AND INHIBITING COMPOSITION AND A METHOD OF PREPARATION THEREOF"

Abstract A rust reforming and inhibiting composition comprising latex in amount of 55-65%, tannic acid in an amount of 3-6%, oxalic acid in an amount of 3-6%, anti-foaming agent in an amount of 3-6%, clay in an amount of 2-5%, zinc oxide in an amount of 0.5-1%, Barium Chloride in an amount of 0.5-1%, wetting agent in an amount of 0.5-1%, wherein the said composition optionally contains an oxygen scavenger, all amounts being expressed in terms of weight of the total composition, the entire composition being dispersed in water.
Full Text Field of the invention
The present invention relates to a rust reforming and inhibiting composition. More particularly, the present invention relates to a rust reforming and inhibiting coating composition which is applicable across a host of surfaces, enabling the reforming of rust formed on ferro-metallic surfaces and preventing the formation of further rust thereon. The composition of the invention finds application in several industries such as shipping, automobile, petroleum and petrochemical industries, cement and steel industries, construction, agro-based industries, pipelines, storage tanks, railways, dams and bridges, food and beverage industries, defence installations, water supply industries, and the like. Background of the invention
Corrosion and rusting and associated problems result in tremendous losses in several industries, particularly in the fields of plant, machinery, storage tanks, pipelines, construction, and the like. The losses take the form of actual corrosive damage and reduction in operational life of the equipment, thereby resulting in losses due to maintenance, shut down, repair time, and the like. Rust preventing compositions are a field where a large degree of research has been undertaken with a view to overcome some of the above mentioned problems. It is known in the art to use rust preventers, protectors, enamel and epoxy coatings to overcome or minimize such losses. However such methods are found to be economically not effective, since a multiplicity of coatings are required. It is also found that such coatings need to be applied at periodic intervals, thereby resulting in a recurrent cost. Anodier problem faced with some of the prior art compositions is that they result in a reduction of the strength of the ferrometalhc surface to which they are applied due to the presence of phosphates therein, thereby reducing the life of the substrate.
US Patent 3,753,924 discloses a rust inhibitor containing tannins with a chelation catalyst and a cross-linking agent. The composition of this patent comprises essentially a rust inhibitor such as tannic acid, and a catalyst capable of initiating chelation of iron atoms such as aluminium sulfate, ferric chloride, stannic
chloride, maleic acid, oxalic acid, and phthalic acid, and a and cross linking agent such as formaldehyde, glyoxal, hexamethylene diamine, and paraphenylene diamine.
Japanese Patent 11246311 teaches a rust control agent containing an active compound isolated from Zingiber officinale Rose, and mixing the active compound with a carrier, a surfactant, a dispersant, an auxiliary and the like.
US Patents 4,363,889; 4,239,804; 6,464,763; 5,239,002 all disclose various water soluble compositions for surface coating to prevent atmospheric corrosion of substrates. However, none of the above patents teach the inhibition and prevention of corrosion.
Another disadvantage of prior art rust preventive or rust inhibiting compositions is that their action is physical — i.e. they prevent the formation of rust by forming a coating on the substrate. As a result of natural conditions, such coatings tend to degrade and erode over a period of time and therefore require repeated application as indicated above. The physical functioning of such coatings also means that once rust sets in on the substrate, the rust layer itself tends to result in the peeling off of the coating, thereby exposing further portions of the substrate to oxidation and formation of rust.
It is therefore imperative to provide compositions which while enabling the reforming of rust from ferrometalic surfaces do not degrade the surface, do not require repeated applications and at the same time are economically efficient. It is also important that such compositions function not just physically as a coating on the ferrometaUic substrates but actually chemically remove rust therefrom and also prevent the formation of rust thereon. Objects of the invention
The main object of the invention is to provide a rust reforming and inhibiting composition which does not degrade the ferrometaUic surfaces.
It is another object of the invention to provide a rust reforming and inhibiting composition which does not require repeated application and is also economically efficient.
It is a further object of the invention to provide a rust reforming and inhibiting composition which possesses a longer life and is more durable.
Summary of the invention
The present invention provides a rust reforming and inhibiting composition which comprises a synergistic mixture of latex, tannic acid, oxalic acid, anti-foaming agent, clay, zinc oxide, barium chloride, wetting agent, the mixture being dissolved in water.
Accordingly, the present invention provides a rust reforming and inhibiting composition comprising latex in an amount of 55 — 65%, tannic acid in an amount of 3 — 6%, oxalic acid in an amount of 3 to 6%, antifoaming agent in an amount of 3 to 6%, clay in an amount of 2 — 5%, zinc oxide in an amount of 0.5 to 1%, barium chloride in an amount of 0.5 to 1%, a wetting agent in an amount of 0.5 to 1%, all amounts being expressed in terms of weight of the total composition, the entire composition being dispersed in water.
In another embodiment of the invention, the composition also includes an oxygen scavenger selected from the group consisting of ascorbic acid, aminopolycarboxylic acid, sodium sulphate, diethyl hydroxyl amines and pyrogaliic acid.
In another embodiment of the invention, the latex used is preferably acid stabilized to a pH in the range of 2 to 5.
In yet another embodiment of the invention, the anti-foaming agents comprise conventional anti-foaming agents such as silicon based defoamers.
In a further embodiment of the invention, the clay used is preferably a thixOtropic flow modifier such as a mineral colloid.
In another embodiment of the invention, the wetting agent is preferably selected from ethylene glycol and esters thereof
The composition of the invention is a synergistic composition with unexpected properties over the aggregate properties of the individual ingredients. Specifically, it is noted that the composition of the invention results in the formation of a non-corrosive organometaliic matrix which is easily removable, which property is not seen in any of the individual ingredients.
The present invention also provides a method for the manufacture of a rust reforming and inhibiting composition comprising latex in an amount of 55 — 65%, tannic acid in an amount of 3 — 6%, oxalic acid in an amount of 3 to 6%,
antifoaming agent in an amount of 3 to 6%, clay in an amount of 2 - 5%, zinc oxide in an amount of 0.5 to 1%, bariumchloride in an amount of 0.5 to 1%, a wetting agent in an amount of 0.5 to 1%, all amounts being expressed in terms of weight of the total composition, the entire composition being dispersed in water, the method comprising admixing the above ingredients in the ranges of proportions mentioned above imder conditions suitable for the formation of a complete mixture.
In one embodiment of the invention, an oxygen scavenger selected from the group consisting of ascorbic acid, aminopolycarboxyhc acid, sodium sulphate, diethyl hydroxyl amines and pyrogaUic acid is added to the composition. Detailed description of the invention
The present invention provides a rust reforming and inhibiting composition which comprises a synergistic mixture of latex, tannic acid, oxalic acid, anti-foaming agent, clay, zinc oxide, barium chloride, wetting agent, the mixture being dissolved in water. The latex used is preferably acid stabilized to a pH in the range of 2 to 5. The anti-foaming agents comprise conventional anti-foaming agents such as silicon based defoamers. The clay used is preferably a thixottopic flow modifier such as a mineral colloid. The wetting agent is preferably selected from ethylene glycol and esters thereof
The composition of the invention when applied to any ferrometaliic substrate reacts with the surface and sub-surface rust and changes it chemically to a non-corrosive organo-metaliic complex. This results in the stabilization of the surface and also arrests the process of rusting. A significant advantage of the composition of the invention is that it does not contain phosphoric acid or any phosphates and therefore does not result in a weakening of the ferrometaUic substtate.
The rust already formed on the surface or sub-surface of the ferrometaUic substtate is converted into the form of an organo-metal matrix which is non-corrosive. This matrix is easily removable from the substtate. AdditionaUy, the composition of the invention forms a tenacious polymer coating on the substtate and thereby seals the surface of the substtate from the elements. The polymer coating so formed is sttong and durable thereby ensuring that the surface is not
subjected to further oxidation. The strength of the coating also ensures that repeated periodic applications are not required, thereby saving on the recurrent expenditure and shut down otherwise seen in the use of prior art formulations for rust prevention.
The composition of the invention primarily comprises latex in an amount of 55 — 65%, tannic acid in an amount of 3 — 6%, oxalic acid in an amount of 3 to 6%, antifoaming agent in an amount of 3 to 6%, clay in an amount of 2 — 5%, zinc oxide in an amount of 0.5 to 1%, barium chloride in an amount of 0.5 to 1%, a wetting agent in an amount of 0.5 to 1%, all amovmts being expressed in terms of weight of the total composition, the entire composition being dispersed in water.
The composition of the invention is a synergistic composition with vmexpected properties over the aggregate properties of the individual ingredients. Specifically, it is noted that the composition of the invention results in the formation of a non-corrosive organometallic matrix which is easily removable, which property is not seen in any of the individual ingredients.
The composition of the invention is prepared by admixing the various ingredients in the ranges of proportions mentioned above under conditions suitable for the formation of a complete mixture. If desired, an additional amount of an oxygen scavenger such as ascorbic acid, aminopolycarboxylic acid, sodium sulphate, diethyl hydroxyl amines and pyrogaliic acid can also be added to the mixture.
The present invention will now be described with reference to the following examples which are illustrative and should not be construed as limiting the scope of the invention in any manner. Example 1:
Several batches of the composition of the invention were prepared comprising latex in an amount of 55 — 65%, tannic acid in an amount of 3 — 6%, oxalic acid in an amount of 3 to 6%, antifoaming agent in an amount of 3 to 6%, clay in an amount of 2 — 5%, zinc oxide in an amount of 0.5 to 1%, barium chloride in an amount of 0.5 to 1%, a wetting agent in an amount of 0.5 to 1%, all amounts being expressed in terms of weight of the total composition. The batches were dispersed in water.
Example 2
A mild steel rod was coated with one coating of the composition of the invention. After 26 hours of curing, the rod was immersed in 5 to 10% salt solution in water at normal ambient temperature. On contact with water, a bluish black colored dispersion was obtained. After about 30 minutes, the dispersion in water resulted in solid specks of dark colored particles. The coated mild steel rod was left overnight in water (for about 14 hours) and then dried for about another 14 hours. It was noted that no further rust formed even after prolonged immersion in water. Example 3
Another mild steel rod piece was first coated with the composition of the invention, cured for about 36 hours, and then immersed in boiling water with a saline content of 5 to 10%. After boiling for about 30 minutes, natural reduction in water level and increase in salt concentration did not result in any visible impact on the substrate. The rod piece was removed and dried for 18 to 20 hours. No physical or chemical change was seen thereon, establishing that the composition of the invention prevented rust formation. Example 4
A single coat of the composition of the invention was applied on several rusted pieces of iron sheets and mild steel rods. The coated substrates were then buried in moist mud and kept covered for 2 weeks. The substrates were then washed and dried. No further formation of rust was noted. Example 5
The composition of Example 1 was applied as a single coating on a metal sheet which had been completely rusted as well as on 2 pieces of steel pipes which were partly rusted and on pieces of mild steel rods which were fully rusted. The composition was applied in free flowing form similar to primer paint. The surface drying time was uniform on all surfaces - from 20 - 30 minutes. After drying, the separate pieces of metal were smooth to the touch showing that no granulated pieces which serve as an indication of presence of rust, were present. Example 6
A first coat of the composition of Example 1 was applied on three pieces of mild steel. After 30 minutes, a second coating was applied and it was observed that
the viscosity was good and the spread of the coating on the surface was even. The reaction with the rusted portions was observed to start immediately and a blue-black colour was prevalent after 60 minutes of drying. The samples were shaken vigorously before the second coating and some frothing was observed. A defoaming agent was added to the composition and the experiment repeated. It was observed that the problem of frothing was overcome. Example 7
The experiment of Example 6 was repeated with the addition of an oxygen scavenger to the composition. Separate batches of the composition of example 1 were prepared with different oxygen scavengers selected from ascorbic acid, aminopolycarboxylic acid, sodium sulphate, diethylhydroxyl amines and pyrogallioic acid. It was observed that the performance in terms of rust inhibition was improved significantly. Example 8
The first application was done simultaneously on a fully rusted metal sheet, scraped and cleaned before application, on one side, and on the other surface, which was partially rusted.
a) It was observed after 4 hours of surface drying that the fully rusted sheet had turned completely black and on the partially rusted side, the rusted portions had turned black but the non-rusted portions were coated with a transparent film.
b) After 8 hours and 24 hours/48 hours, there was no further change in the color or texture of the application and the observations made after 4 hours drying was maintained.
c) Water was not splashed on these metal sheets at any time during the drying periods.
Example 9
The composition of the invention was applied simultaneously on three small
pieces of rusted MS rod, and the following was observed.
a) After 4 hrs. surface drying, the first piece was immersed in a beaker of water. Almost immediately the water was discolored as numerous black particles were dispersed from the metal piece and this process continued slowly imtil the water
was dark brown. The metal piece was taken out after 24 hrs. immersion and almost all the composition application was removed.
b) After 8hrs. of svirface drying, the results were almost identical to those observed after 4 hrs. surface drying. The only difference was that the dispersion was no so complete and the resxoltant water in the beaker was only slightly lighter than the earlier experiment. After 24 hrs. immersion, the metal piece was partially covered with the composition.
c) After 24 / 36 Hrs. of surface drying, the third piece was immersed in water. There was no immediate discoloration, but after 2 hrs. of immersion the water was discolored with small black particles. After 24 hrs. immersion, the dispersion remained almost the same, but on removing the metal piece from the water the application was observed to be coming off by touch and rubbing. However, the effect was only minimal though some rusted portions could be observed on the basis where the application had been rubbed off
A fresh composition was prepared by adding further polymer. Example 10
The composition of the invention was kept in an open beaker for 36 hrs. There was some evaporation. Ordinary water was added to the beaker in the "same proportion as that which had evaporated. The resultant mixture was appUed on a rusted metal strip in comparison with the first application of the composition on the same strip — applied 36 hrs. earlier. The sample containing the evaporated solution and diluted by adding water, was applioed side by side and after surface drying of 24 hrs. It was observed that though the original application was completely black and covered the entire applied portion, the diluted application was also quite effective. The applied portion was almost entirely black approx. 90-95% and in the portions where the black coloring did not take place, it was observed that the rusted portions underneath were cured and the application had formed a transparent film over these portions.
The above examples are non-limiting and are illustrative of the composition of the invention. Modifications and variations therefrom are possible without departing from the spirit of the invention.












We claim:
1. A rust reforming and inhibiting composition comprising latex in amount of 55-65%, tannic acid in an amount of 3-6%, oxalic acid in an amount of 3-6%, anti-foaming agent in an amount of 3-6%, clay in an amount of 2-5%, zinc oxide in an amount of 0.5-1%, Barium Chloride in an amount of 0.5-1%, wetting agent in an amount of 0.5-1%, wherein the said composition optionally contains an oxygen scavenger, all amounts being expressed in terms of weight of the total composition, the entire composition being dispersed in water.
2. The composition as claimed in claim 1, wherein the said oxygen scavenger is selected from the group consisting of ascorbic acid, aminopolycarboxylic acid, sodium sulphate, diethyl hdroxyl amines and pyrogallic acid.
3. The composition as claimed in claims 1 or 2, wherein the latex used is preferably acid stabilized to a pH in the range of 2 to 5.
4. The composition as claimed in any of claims 1 to 3, wherein the anti-foaming agents comprise conventional anti-foaming agents such as silicon based defoamers.
5. The composition as claimed in any of claims 1 to 4, wherein the clay used is preferably a thixotropic flow modifier such as mineral colloid
6. The composition as claimed in any of claims 1 to 5, wherein the wetting agent is preferably selected from ethylene glycol and esters thereof.
7. A method for the manufacture of a rust reforming and inhibiting composition comprising latex in an amount of 55 to 65 %, tannic acid in an amount of 3-6%, oxalic acid in an amount of 3-6%, anti-foaming agent in an amount of 3-6%, clay in an amount of 2-5%, zinc oxide in an amount of 0.5-1%, Barium Chloride in an amount of 0.5-1%, wetting agent in an amount of 0.5-1%, wherein the said composition optionally contains an oxygen scavenger, all amounts being expressed in terms of weight of the total composition, the entire composition being dispersed in water, the method comprising admixing the above ingredients in the ranges of proportions mentioned above under conditions suitable for the formation of a complete mixture.
8. The method as claimed in claim 7, wherein the said oxygen scavenger is selected
from the group consisting of ascorbic acid, aminopolycarboxylic acid, sodium
sulphate, diethyl hdroxyl amines and pyrogallic acid.
9. The method as claimed in claims 7 or 8, wherein the latex used is preferably acid
stabilized to a pH in the range of 2 to 5.
10. The method as claimed in any of claims 7 to 9, wherein the anti-foaming agents
comprise conventional anti-foaming agents such as silicon based defoamers.
11. The method as claimed in any of claims 7 to 10, wherein the clay used is preferably a
thixotropic flow modifier such as mineral colloid
12. The method as claimed in any of claims 7 to 11, wherein the wetting agent is preferably selected from ethylene glycol and esters thereof.

Documents:

607-DEL-2003-Abstract-(11-11-2011).pdf

607-del-2003-Abstract-(12-08-2011).pdf

607-DEL-2003-Abstract-(30-05-2011).pdf

607-del-2003-abstract.pdf

607-DEL-2003-Claims-(11-11-2011).pdf

607-del-2003-Claims-(12-08-2011).pdf

607-del-2003-claims.pdf

607-del-2003-Correspodence Others-(12-08-2011).pdf

607-del-2003-Correspondence Others-(06-06-2011).pdf

607-DEL-2003-Correspondence Others-(08-09-2011).pdf

607-DEL-2003-Correspondence Others-(11-11-2011).pdf

607-DEL-2003-Correspondence Others-(19-09-2011).pdf

607-DEL-2003-Correspondence Others-(30-05-2011).pdf

607-del-2003-correspondence-others.pdf

607-del-2003-correspondence-po.pdf

607-DEL-2003-Description (Complete)-(11-11-2011).pdf

607-del-2003-description (complete).pdf

607-del-2003-description (provisional).pdf

607-del-2003-Form-1-(06-06-2011).pdf

607-DEL-2003-Form-1-(11-11-2011).pdf

607-del-2003-Form-1-(12-08-2011).pdf

607-DEL-2003-Form-1-(30-05-2011).pdf

607-del-2003-form-1.pdf

607-del-2003-form-18.pdf

607-DEL-2003-Form-2-(11-11-2011).pdf

607-del-2003-form-2.pdf

607-del-2003-form-3.pdf

607-del-2003-form-4.pdf

607-del-2003-Form-5-(06-06-2011).pdf

607-DEL-2003-Form-5-(19-09-2011).pdf

607-DEL-2003-Form-5-(30-05-2011).pdf

607-del-2003-form-5.pdf

607-del-2003-gpa.pdf

607-DEL-2003-Petition-137-(19-09-2011).pdf


Patent Number 250111
Indian Patent Application Number 607/DEL/2003
PG Journal Number 49/2011
Publication Date 09-Dec-2011
Grant Date 07-Dec-2011
Date of Filing 16-Apr-2003
Name of Patentee INDIAN INSTITUTE OF TECHNOLOGY-DELHI
Applicant Address HAUZ KHAS, NEW DELHI-110 016, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 GHOSH, A.K. INDIAN INSTITUTE OF TECHNOLOGY, DELHI, (IIT), HAUZ KHAS, NEW DELHI 110 016, INDIA.
2 JASWAL, SURINDER INDIAN INSTITUTE OF TECHNOLOGY-DELHI-(IIT), HAUZ KHAS, NEW DELHI 110 016, INDIA.
PCT International Classification Number B05D 7/14
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA