DESC:EARLIEST PRIORITY DATE:
This application claims priority from a provisional patent application filed in India having patent application no. 202411027734, filed on April 03, 2024, and titled “A METHOD TO FORM A HOMOGENEOUS PROTECTIVE COATING FROM A WATER BASED SOLUTION”.
FIELD OF INVENTION
[0001] Embodiments of the present disclosure relate to the field of metal corrosion prevention techniques, and more particularly, a method for coating a water-wax based solution on a metal surface to prevent corrosion.
BACKGROUND
[0002] Corrosion during sea shipment is a common concern, particularly for metallic items. The marine environment, characterized by high levels of moisture, salt, and other corrosive elements, can accelerate the corrosion process. There are several factors contributing to corrosion during sea shipment and preventive measures.
[0003] Sea air contains high levels of moisture and salt, which can accelerate corrosion. When metallic surfaces are exposed to these elements for extended periods, they are prone to rusting and corrosion. The duration of sea shipment plays a crucial role, the longer the exposure, the greater the risk of corrosion. Items shipped over long distances are at a higher risk of corrosion compared to shorter shipments. Additionally, improper packaging or handling can expose metallic items to moisture and salt during loading, unloading, and transit. Therefore, using appropriate packaging materials and techniques is crucial to minimizing exposure.
[0004] Applying protective coatings such as paints, varnishes, or corrosion inhibitors can provide a barrier against moisture and salt exposure, thereby reducing the risk of corrosion. For metallic components that require further processing, such as engine parts, moving or mating parts are coated with rust preventive oils which leave a very thin protective film ranging from 1-10 micron. Such coatings do not need to be removed before subsequent operations, do not interfere with part functionality, and do not contaminate further processing.
[0005] Solvent-based rust preventive oils are coating designed to protect metal surfaces from corrosion. These oils typically contain a mixture of solvents, rust inhibitors, and sometimes lubricants. The solvents are used to carry the rust inhibitors and lubricants onto the metal surface, where they form a protective film that inhibits oxidation and prevents rust formation. Solvents offer a key advantage due to their low surface tension, enabling them to completely wet the metal surface and distribute inhibitors homogeneously. Furthermore, solvents evaporate quickly, leaving behind a uniform corrosion inhibitor layer almost immediately.
[0006] A cheaper and more environmentally friendly alternative to solvent-based coatings is the use of water along with corrosion inhibitors and oil. However, water has a significantly higher surface tension compared to solvents, making it difficult to completely wet metallic surfaces and form a uniform film. Even if water is made to wet the surface effectively, its slow evaporation rate prevents the formation of the desired homogeneous layer. These two factors hinder the ability of water-based coatings to create an even and effective corrosion inhibitor layer. While higher temperatures can be used to speed up water evaporation, the resulting film formation is still inferior to that of solvent-based corrosion inhibitors. Due to these limitations, water-based rust preventives are generally not trusted for protecting parts during sea transport or extended storage.
[0007] Hence, there is a need for a method for coating a water-wax based solution on a metal surface to prevent corrosion which addresses the aforementioned issue(s).
OBJECTIVES OF THE INVENTION
[0008] Primary objective of the invention is to create a method for corrosion prevention that utilizes a temperature difference between a heated, stable water-wax based solution and a cooler metal surface, facilitating immediate formation of a protective layer.
[0009] Another objective of the invention is to ensure that the water-based solution freezes upon contact with the metal surface, which has a lower temperature than the water-based solution, effectively forming a uniform and durable corrosion-preventive layer.
BRIEF DESCRIPTION
[0010] In accordance with another embodiment of the present disclosure, a method for coating a water-wax based solution on a metal surface to prevent corrosion is provided. The method includes preparing the water-wax based solution. The water-wax based solution includes 1 to 35 percentage by weight of a base wax. The water-wax based solution includes 3 to 10 percentage by weight of an emulsifying agent. The water-wax based solution includes 1 to 35 percentage by weight of an oil. The water-wax based solution includes 1 to 35 percentage by weight of water. The water-wax based solution includes 1 to 5 percentage by weight of a plurality of additive. The method includes diluting the water-wax based solution with a pre-determined volume of water at a first predefined temperature to achieve a desired coating thickness as per requirement. The method includes exposing the metal surface maintained at a second predefined temperature lower than the first predefined temperature, to the water-wax based solution, thereby facilitating the formation of a uniform protective layer due to the temperature difference. The method includes freezing the water-wax based solution upon contact with the metal surface, thereby forming a corrosion-resistant coating.
[0011] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:
[0013] FIG. 1 illustrates a flow chart representing the steps involved in a method for coating a water-wax based solution on a metal surface to prevent corrosion in accordance with an embodiment of the present disclosure.
[0014] Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
DETAILED DESCRIPTION
[0015] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.
[0016] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or subsystems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.
[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.
[0018] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
[0019] Embodiment of the present disclosure relates to a method for coating a water-wax based solution on a metal surface to prevent corrosion. The method includes preparing the water-wax based solution. The water-wax based solution includes 1 to 35 percentage by weight of a base wax. The water-wax based solution includes 3 to 10 percentage by weight of an emulsifying agent. The water-wax based solution includes 1 to 35 percentage by weight of an oil. The water-wax based solution includes 1 to 35 percentage by weight of water. The water-wax based solution includes 1 to 5 percentage by weight of a plurality of additive. The method includes diluting the water-wax based solution with a pre-determined volume of water at a first predefined temperature to achieve a desired coating thickness as per requirement. The method includes exposing the metal surface maintained at a second predefined temperature lower than the first predefined temperature, to the water-wax based solution, thereby facilitating the formation of a uniform protective layer due to the temperature difference. The method includes freezing the water-wax based solution upon contact with the metal surface, thereby forming a corrosion-resistant coating.
[0020] FIG. 1 illustrates a flow chart representing the steps involved in a method (100) for coating a water-wax based solution on a metal surface to prevent corrosion in accordance with an embodiment of the present disclosure. Corrosion is a natural process that converts a metal into a more chemically stable oxide. The corrosion is the gradual deterioration of the metal by chemical or electrochemical reaction with their environment. Examples of metals that may benefit from the method (100) include, but are not limited to, iron, steel, aluminum, copper, zinc, and the like. The water-wax based solution is applied to the surface of any of these metals.
[0021] The method (100) includes preparing the water-wax based solution in step 110. The water-wax based solution includes 1 to 35 percentage by weight of a base wax. Examples of the base wax includes but not limited to petroleum wax, paraffin wax, soya wax, carnauba wax, beeswax, and the like. The base wax is solid at room temperature but become viscous liquids when heated above their melting points.
[0022] In an embodiment, the soya wax is preferred for auto components due to its higher melting point (above 65°C), making it suitable for parts exposed to high temperature washing.
[0023] It is noted that the base wax may be partially dissolved in oil to produce a softer coating that is less prone to flaking.
[0024] Alternatively, the base wax may be substituted with grease or other coatings that are soluble in water only at higher temperatures.
[0025] The water-wax based solution includes 3 to 10 percentage by weight of an emulsifying agent. The emulsifying agent helps in stabilizing the wax-water based solution and maintaining its homogeneity. Examples of the emulsifying agent include but are not limited to TWEEN 80, and the like.
[0026] The water-wax based solution includes 1 to 35 percentage by weight of an oil. Paraffin oil is primarily used, but other oils that may soften the base wax and add lubricity to the coating may also be used. The oil prevents the base wax from becoming hard and flaky, maintaining a slightly viscous and lubricating surface.
[0027] In one embodiment, the solution may include or exclude oil in a water medium to prevent both localized and general corrosion on multi-metal surfaces exposed to humid or coastal environments.
[0028] The water-wax based solution includes 1 to 35 percentage by weight of water. The water's temperature is kept above the base wax's melting point to maintain a homogeneous mixture. A high-shear mixer may be used to disperse the wax thoroughly.
[0029] The water-wax based solution includes 1 to 5 percentage by weight of a plurality of additive. Examples of the plurality of additive includes but not limited to rust inhibitor, preservatives, and the like. The rust inhibitors enhance the corrosion resistance of the coating. Preservatives may extend the shelf life of the wax-water emulsion, preventing microbial growth.
[0030] The specific composition of the base wax, plurality of additive, oils, and the emulsifying agent may vary depending on the temperature of the metal to be coated and the desired thickness of the coating. These suitable compositions may be determined through a routine testing by professionals in the field by means of routine trials.
[0031] Components of the water-wax-based solution are combined by first heating the base wax in a double boiler. Oils and other additives are added sequentially, followed by water, to create the final concentrate. The final concentrate may be made viscous to facilitate pouring and mixing with water to achieve the desired coating thickness.
[0032] In one embodiment, the concentration of the emulsifying agent is preferably adjusted to a lower dosage so that the wax emulsion does not remain homogeneous at lower or ambient temperatures. Instead, the emulsifying agent becomes homogeneous only when the suggested temperature is reached. If the emulsifying agent concentration is too high, the wax emulsion may remain homogeneous even at lower or room temperature, which would prevent effective freezing and coating of the component.
[0033] In an embodiment, the wax-water based solution is heated to maintain homogeneity and stability before application on the metal surface.
[0034] The method (100) includes diluting the water-wax based solution with a pre-determined volume of water at a first predefined temperature to achieve a desired coating thickness as per requirement in step 120. The pre-determined volume of water can be adjusted based on the composition of the water-wax-based solution.
[0035] The first predefined temperature is the refers to the optimal temperature of the water-wax solution for effective metal coating, determined by the melting point of its components.
[0036] The method (100) includes exposing the metal surface maintained at a second predefined temperature lower than the first predefined temperature, to the water-wax based solution, thereby facilitating the formation of a uniform protective layer due to the temperature difference in step 130. The second predefined temperature is the temperature that the metal surface must maintain during the coating process. The water-wax solution remains stable at or above this second predefined temperature.
[0037] In one embodiment, the metal surface is dipping in cold water before being exposed to the water-wax based solution, thereby reducing the temperature of the metal surface to the second predefined temperature.
[0038] It must be noted that the water-wax-based solution is applied on the metal surface using at least one of spraying, dipping, brushing, and flow coating.
[0039] Specifically, when a metal surface is just below a solidification temperature of the wax or wax-oil mixture is dipped in the solution, the wax solidifies immediately on contact. As the wax solidifies, oils, corrosion inhibitors, and additives from the solution also solidify, forming the uniform protective film.
[0040] The method (100) includes freezing the water-wax based solution upon contact with the metal surface, thereby forming a corrosion-resistant coating in step 140. The corrosion-resistant coating formed due to temperature difference and freezing of base wax along with the plurality of additive on such metal surfaces.
[0041] Let’s consider an example where the method (100) is applied. A 1010 steel panel polished with 600 emery paper is dipped in the wax-water based solution which contains 80-85% water, 5-10% Soya and Paraffin wax, 5-10% paraffin oil and 5% of emulsifiers (TWEEN 80). The wax-water based solution is heated to or above 75°C to ensure homogeneous dilution of the base wax in the water. The polished steel panel, maintained at room temperature, is dipped into the solution for 1 second. After resting for 45 minutes, the coated panel is sprayed with a 1% NaCl solution and placed in a controlled environment containing 10 ml of a glycerin-water mixture (1:4 ratio) to create humidity.
[0042] Another 1010 steel sample, also polished with 600 emery paper as control is also sprayed with 1% NaCl solution and then kept in the same container as coated sample. Visual inspection of corrosion on both samples is conducted, and the results are summarized in Table 1.
Table 1
Corrosion tests on 1010 steel coupon
Example Results
Control Sample Rust within 1 hours
Coated Sample No rust for 24 hours
[0043] The results in Table 1 show the coated sample exhibits superior corrosion resistance, showing no visible rust even after 24 hours, while the control sample begins rusting within 1 hour.
[0044] In another test, the 1010 steel panel are dipped in 1% NaCl solution for 6 hours and then dried to observe rust formation. The control sample fully rusts, whereas coated sample shows appreciable protection against rust, with only about 3-5% of the surface area rusted compared to the 100% rusted area of the control sample. It is noted that no rust inhibitor additive is used in the above testing, and the rust prevention results solely from the coating layer.
[0045] Various embodiments of the method (100) for coating a water-wax based solution on a metal surface to prevent corrosion as described above provide several advantages. The method provides an effective corrosion-preventive layer on metal surfaces by utilizing the temperature difference between the water-wax based solution and the metal surface. The wax-based corrosion-resistant coating enhances durability, offers long-lasting resistance to corrosion under various environmental conditions, and is environmentally friendly. Additionally, the use of readily available waxes, oils, and emulsifying agents makes the method cost-effective for large-scale implementation.
[0046] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the disclosure and are not intended to be restrictive thereof.
[0047] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.
[0048] The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.
,CLAIMS:1. A method (100) for coating a water-wax based solution on a metal surface to prevent corrosion, comprising:
preparing the water-wax based solution, wherein the water-wax based solution comprises:
1 to 35 percentage by weight of a base wax;
3 to 10 percentage by weight of an emulsifying agent;
1 to 35 percentage by weight of an oil;
1 to 35 percentage by weight of water; and
1 to 5 percentage by weight of a plurality of additive; (110)
diluting the water-wax based solution with a pre-determined volume of water at a first predefined temperature to achieve a desired coating thickness as per requirement; (120)
exposing the metal surface maintained at a second predefined temperature lower than the first predefined temperature, to the water-wax based solution, thereby facilitating the formation of a uniform protective layer due to the temperature difference; and (130)
freezing the water-wax based solution upon contact with the metal surface, thereby forming a corrosion-resistant coating. (140)
2. The method (100) as claimed in claim 1, wherein the base wax comprises at least one of petroleum wax, paraffin wax, soya wax, carnauba wax, or beeswax.

3. The method (100) as claimed in claim 1, wherein the oil is paraffin oil.

4. The method (100) as claimed in claim 1, wherein the plurality of additive comprises rust inhibitor and preservatives.

5. The method (100) as claimed in claim 1, comprising dipping the metal surface in cold water before exposing to the water-wax based solution, thereby reducing the temperature of the metal surface to the second predefined temperature.

6. The method (100) as claimed in claim 1, wherein the first predefined temperature is set based on the temperature of a component of the water-wax-based solution.

7. The method (100) as claimed in claim 1, wherein the water-wax-based solution is stable at or above the second predefined temperature.

8. The method (100) as claimed in claim 1, wherein the wax-water solution is heated to maintain homogeneity and stability before application on the metal surface.

9. The method (100) as claimed in claim 1, wherein the water-wax-based solution is applied on the metal surface using at least one of spraying, dipping, brushing, and flow coating.

Dated this 25th day of March 2025
Signature

Prakriti Bhattacharya
Patent Agent (IN/PA-5178)
Agent for the Applicant