A METHOD TO APPLY COATING ON A BARBED WIRE
BUNDLE TO ENHANCE CORROSION RESISTANCE PROPERTIES

FIELD OF INVENTION:

[001] The present subject matter described herein, relates to a method to enhance corrosion resistance properties of a barbed wire. The present subject matter in particularly relates to a method to apply uniform coating on a barbed wire bundle to enhance corrosion resistance properties and increase the life span of the barbed wire.
BACKGROUND AND PRIOR ART AND PROBLEM IN PRIOR ART:
[002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[003] Barbed wire is a type of fencing wire constructed with sharp edges or point arranged at interval along the strands. Barbed wires are primarily used by the farmers to restrict unwanted persons or animals from their agricultural fields. Barbed wires are mainly manufactured from carbon steel which are not resistant to corrosion.
[004] In normal environmental conditions barbed wires are prone to corrosion. To increase barbed wire’s life expectancy, zinc coating is provided on the outer surface of the carbon steel barbed wires. Higher the zinc coating thickness higher is the life expectancy of fencing. But higher zinc coating leads to increase in the price of barbed wires. Currently, the available barbed wires in the market use zinc coating of 90 mg/sq. m which is about 12-micron thick. These barbed wires have a life expectancy of 4-8 years depending on the environmental conditions.
[005] Currently, few wire manufacturers do in-line secondary coating on wire galvanizing lines which gives limited life improvement to the fencing. Further, galvanized barb wires are painted after fencing to further increase their life span.
[006] International application WO2002068704A1 discloses colored wire and method for manufacturing the same. In this patent the color coating is applied on-line on the wire.
[007] Indian Patent 307038 discloses organic coating application on galvanized iron wire. It also mentioned on-line coating process to enhance corrosion resistance properties of wire.
[008] International application WO2015128364 describe sol-gel coating formulation on galvanized iron wire for enhance corrosion resistance properties.
[009] Technical Problem: The conventional solutions such as higher zinc coating or applying paint on wire increases the production cost to very high level making barbed wire costlier. Further, the in-line secondary coating on wire galvanizing lines gives limited life improvement due to lower thickness of coating and damages of secondary coating during barbing operation as coating was done before barbing operation. Also, uniform coating on barbed wire of complex shape is challenging as compared to plain wires.
[0010] Technical objective: A method is required for applying coating on the barbed wire bundle to decrease cost of coating.
[0011] The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
OBJECTS OF THE INVENTION:
[0012] It is therefore the object of the invention to overcome the aforementioned and other drawbacks in prior method/product/apparatus.
[0013] The principal objective of the present invention is to develop a method to apply uniform coating on a barbed wire bundle to enhance corrosion resistance properties of the barbed wire.
[0014] Another object of the present invention is to develop a method to apply uniform coating on a barbed wire bundle to reduce production time and manufacturing cost.
[0015] Another object of the present invention is to develop a method to apply uniform coating on a barbed wire bundle in order to avoid damage of secondary coating.
[0016] Yet another object of the present invention is to develop a method to apply uniform coating on a barbed wire bundle to avoid application of subsequent paint to enhance life span of barbed wire.
[0017] Yet another object of the present invention is to provide develop a method to apply uniform coating on a barbed wire bundle in which applying operation and drying operation is done simultaneously.
[0018] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.
SUMMARY OF THE INVENTION:
[0019] Solution to one or more drawbacks of conventional method for applying coating on barbed wires, and additional advantages are provided through the method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
[0020] The present subject matter relates to a method to apply uniform coating on a barbed wire bundle to enhance corrosion resistance properties and increase the life span of the barbed wire.
[0021] In an embodiment, the present subject matter discloses a method to apply coating on a barbed wire bundle to enhance corrosion resistance properties, the method includes degreasing the barbed wire bundle by an alkali solution to de-contaminate the barbed wire surface from oil, grease or any oxide; cleaning the alkali treated barbed wire bundle from demineralized water; passivating the cleaned barbed wire bundle to improve adhesion of coating on barbed wire bundle surface; dipping a portion of the passivated barbed wire bundle in liquid coating bath and simultaneously keeping the remaining portion of the passivated barbed wire bundle exposed to hot air conditions for drying; horizontally rotating the coated barbed wire bundle to uniformly coat the adjacent portion of the coated barbed wire bundle and simultaneously drying the freshly coated part of the bundle for successive coating; maintaining the rotation of the coated barbed wire bundle until desired thickness of coating is achieved and rotating the coated barbed wire bundle at high speed to remove trapped coating liquid from the coated barbed wire bundle.
[0022] In an aspect, the liquid coating solution of liquid coating bath is selected from organic coating, polymer coating, sol-gel coating or any liquid coating of combinations thereof.
[0023] In an aspect, pigments of desired color are introduced in the liquid coating solution of the liquid coating bath to provide vibrant colorful look to the coated barbed wire.
[0024] In an aspect, the number of rotation of barbed wire bundle in liquid coating bath ranges from 2 rotations to 20 rotations depending on the desired thickness of coating ranging from 5µm to 50µm.
[0025] In an aspect, the temperature of hot air condition maintained around the liquid coating bath ranges from 25oC to 100oC depending on the type of liquid coating solution used for coating.
[0026] In an aspect, the barbed wire bundle is rotated in vertical or horizontal position at a speed of 100 rpm to 500 rpm to remove extra liquid during degreasing, passivating and after coating.
[0027] In an aspect, wherein after coating, the barbed wire bundle is subjected to temperature varying from room temperature to 180oC depending on the type and material of liquid coating solution.
[0028] In an aspect, the structure of barb wire can be any one from single barb, double barb, conventional twist, reverse twist, single stand and double stand.
[0029] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[0030] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0032] Fig. 1 illustrates flow diagram of method, in accordance with an embodiment of the present subject matter;
[0033] Fig. 2 illustrates barbed wire bundle without coating and barbed wire bundle after coating; and
[0034] Fig. 3a and 3b illustrates regular barb wire and coated barb wire respectively, after 72 hours’ exposure in salt spray test.
[0035] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0036] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
[0037] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.
[0038] The present subject matter relates to a method to apply uniform coating on a barbed wire bundle to enhance corrosion resistance properties and increase the life span of the barbed wire.
[0039] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0040] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0041] The present subject matter discloses a method to apply uniform coating on the barbed wire bundle as a whole, to decrease production time and increase efficiency. According to present subject matter, coating is applied on the galvanized barbed wire bundles after barbing operation. Therefore, coating covers all cut and damaged portion of galvanized coated surface developed due to barbed forming operation. Further, simultaneous applying of coating and drying of coating is done, so that coating of required thickness is achieved at once.
[0042] Referring to Figure 1, illustrating flow diagram of method, in accordance with an embodiment of the present subject matter. At step 101, degreasing of barbed wire bundle is done to de-contaminate the barbed wire surface from oils, grease, or any oxide. These contaminants hinder the adhesion of coating on barbed wire surface and leads to poor coating. Depreciation of poor coating occurs earlier than expected. As a result of which life span of barbed wires reduces dramatically. Degreasing of barbed wire bundle is done by using alkali solution. One such example can be solution made up sodium hydroxide sodium carbonate and other additives. The alkali solution which do not affect the coating performance is used for degreasing. The alkali solution removes the contaminants from the barbed wire surface as a consequence of which adhesion property of barbed wire is enhanced.
[0043] At step 102, the alkali treated barbed wire bundles obtained at the step 101 are cleaned with demineralized water (DM water). The DM water removes the traces of alkali solutions from the surface of the barbed wire bundle. After the cleaning process with DM water, the barbed wire bundle is de-contaminated from every kind of impurity like oils, grease, any oxide or alkali solution. After treatment of barbed wire with DM water, the barbed wire is in order for passivation.
[0044] At step 103, passivation is performed on the surface of the barbed wire bundle to improve the adhesion property of the barbed wire bundle for application of coating. During passivation, a thin layer of substrate is applied on the cleaned surface of the barbed wire bundle. The thin layer of substrate enhances adhesion property of the surface. The passivation solution is an inorganic composition primarily comprising of either chromium compound, titanium compound, vanadium compound, or their mixture in acidic electrolytic condition. As the passivation solution is applied on the barbed wire bundle which have non-uniform surface structure, it leads to trapping of solution on the barb surface. This trapping of solution leads to non-uniform coating at later stages. To avoid non-uniform coating, the passivated barbed wire bundle is rotated horizontally or vertically at a speed in range 100 rpm to 500 rpm to remove trapped substrate in the barbed wire bundle. However, passivation is an optional operation and it can be eliminated. With the passivation better results are achieved as explained in table 1.
[0045] At step 104, coating process for the barbed wire bundle is initiated. A portion of passivated barbed wire bundle is dipped in a liquid coating bath for coating and remaining portion is kept outside the liquid coating bath. The temperature around the liquid coating bath is maintained so as to facilitate the drying of coated portion. The temperature around the liquid coating bath depends on type of coating applied on the barbed wire bundle. The temperature of hot air condition maintained above the liquid coating bath ranges from 25o C to 100o C depending on the type of liquid coating solution used for coating.
[0046] The coating material in the liquid coating bath depends on the type of coating being performed on the barbed wire bundle. Method disclosed in present subject matter can be applied to any kind of organic coating, paint coating, polymer coating, sol-gel coating or any liquid coating combination thereof, which can enhance corrosion resistance property of the barbed wire bundle.
[0047] According to one embodiment of the present invention, the organic coating is applied on the barbed wire bundle. The organic coating applied is a polymer based coating formulation comprises of water based polymer, corrosion inhibitor and other functional additives. The formulation of the organic coating in the present can be taken from Indian patent number 299778 which describes the coating formulation chemistry. Vibrant colors are introduced during coating operation by adding pigments of desired color in organic coating formulation. Properly formed organic coating gives very good barrier protection which enhance corrosion resistance properties of the produced barbed wire bundle. Like other coatings, life span of the organic coated barbed wire depends on coating quality, coating chemical used and thickness of coating.
[0048] At step 105, the barbed wire bundle is kept rotating at a constant speed for uniform application of liquid coating. As the bundle is rotated, the adjacent portion of the barbed wire bundle is slowly dipped in the liquid coating bath and the coated portion slowly comes out of the liquid coating bath. The atmosphere above the liquid coating bath is maintained at a temperature to facilitate simultaneous drying of the coated portion of the barbed wire bundle. In case of organic coating, the temperature above the liquid coating bath is maintained in the range of 25oC to 100oC. As soon as the coated portion comes out of the liquid coating bath, the coating applied on the barbed wire bundle starts drying due to the hot temperature maintained around the liquid coating bath.
[0049] At step 106, the rotation of barbed wire bundle in the liquid coating bath continues until pre-determined thickness of coating is achieved. The speed of rotation is maintained in a way such that, when coated portion is again dipped in the liquid coating bath, the previous coating is partially dried up. The uniform rotation speed ensures uniform coating on the surface of barbed wire bundle. The rotation speed during organic coating is maintained in the range of 0.5 rpm to 5 rpm and a total of 2 complete rotations to 20 complete rotations are performed depending on the predetermined thickness of coating.
[0050] At step 107, as the coating is applied on the barbed wire bundle that have non-uniform surface structure, it leads to trapping of liquid coating on the barb surface. To avoid this trapping of the liquid coating, the coated barbed wire bundle is rotated horizontally or vertically at a speed of 100 rpm to 500 rpm to remove coating liquid trapped in the coated barbed wire bundle.
[0051] The coated barbed wire bundle can be further cured at a temperature ranging from room temperature to 180oC. The present curing process is optional and depends upon the coating properties.
[0052] Referring to figure 2 illustrating barbed wire bundle without coating and barbed wire bundle after coating. The barbed wire manufactured with the present method produced uniformly coated vibrantly colored barbed wire bundle. The present method saves production time and increase efficiency of whole coating process, as application of coating film and drying of the coating film is done simultaneously. Further, the required thickness of coating is formed on the barbed wire at once which reduces the cost of manufacturing. Also, coating is done after barbing operation so coating covers all cut and damaged portion of galvanized coated surface developed due to barbed forming operation.
SCALE TEST
[0053] Pilot scale test were performed on five samples at different process condition. The organic coating is applied on the subject barb wire bundles. The result table is shown below:
Table 1:
Sample No.
Process coatings Test Results Final Product
Cleaning Passivation Organic Coating Coating Thickness range (µm) 10% red rust in SST (h)
1 No No No NA 72 Regular GI
2 Yes Yes Yes 11-18 768 Color coated GI
3 Yes No Yes 11-18 504 Color coated GI
4 Yes Yes Yes 6-9 528 Colour coated GI
5 Yes No Yes 6-9 384 Colour coated GI

[0054] In the table 1, the impacts of three major steps of present method are shown. The major steps are cleaning, passivation, and organic coating. The coated samples were characterized for organic coating thickness and corrosion resistance properties. The coating thickness was determined using Confocal Laser Scanning Microscope. The corrosion resistance properties of color coated barbed wires and regular GI wires were evaluated by Salt Spray Test (SST) as per ASTM B117. The samples were exposed inside the salt spray chamber and was observed on each working day till the samples get minimum 10 % red rust. The maximum salt spray resistance of 768 h was observed on wire that was passivated and organic coated. The salt spray resistance lowered to 528 h on sample that was passivated and coated with lower thickness (6-9 ?m). The regular GI sample showed about 72 of salt spray resistance.
[0055] Referring to figure 3 which shows the photographs of samples after 72 h of salt spray test. The regular wire (without organic coating) rusted in 72 hours whereas the color coated wire was not rusted and shining. All color coated wires showed similar appearance after 72 h and therefore only one sample is shown in Figure 3 to represent the color coated sample appearance.
[0056] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
[0057] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.
[0058] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:

1. A method (100) to apply coating on a barbed wire bundle to enhance corrosion resistance properties, the method (100) comprises steps of:
degreasing (101) the barbed wire bundle by an alkali solution to de-contaminate the barbed wire surface from oil, grease or any oxide;
cleaning (102) the alkali treated barbed wire bundle from demineralized water; and
applying coating on the cleaned alkali treated barbed wire bundle.
2. The method (100) as claimed in claim 1, wherein the method further comprising:
passivating (103) the cleaned alkali treated barbed wire bundle by applying a thin layer of substrate to enhance adhesion property of the coating on the barbed wire bundle surface and subsequently rotating the passivated barbed wire bundle to remove trapped substrate from the barbed wire bundle.
3. The method (100) as claimed in claim 1, wherein the applying coating comprises steps of:
dipping (104) a portion of the cleaned alkali treated barbed wire bundle in a liquid coating bath;
rotating (105) the barbed wire bundle in the liquid coating bath to apply uniform coating and simultaneously drying the freshly coated part of the bundle in a hot air condition for successive coating; and
rotating (107) the coated barbed wire bundle at high speed to remove trapped coating liquid from the coated barbed wire bundle.
4. The method (100) as claimed in claim 1, wherein liquid coating solution of liquid coating bath is selected from organic coating, polymer coating, sol-gel coating or any of combinations thereof.
5. The method (100) as claimed in claim 4, wherein the organic coating solution of the liquid coating bath comprises of a water based polymer, corrosion inhibitor and other functional additives such as coloring agent, adhesion promoter, wetting agent etc.
6. The method (100) as claimed in claim 1, wherein the alkali solution used for degreasing the barbed wire bundle.
7. The method (100) as claimed in claim 1, wherein the passivation coating solution is an inorganic composition primarily comprising of either chromium compound, titanium compound, vanadium compound, or their mixture in acidic electrolytic condition.
8. The method (100) as claimed in claim 1, wherein a plurality of pigments of a color is added in the liquid coating solution of the liquid coating bath to provide the color to the coated barbed wire.
9. The method (100) as claimed in claim 1, wherein the barbed wire bundle is rotated in the liquid coating bath with a number of rotation in range from 2 rotations to 20 rotations depending on the predetermined thickness of applied coating that is ranging from 5µm to 50µm.
10. The method (100) as claimed in claim 3, wherein the temperature of hot air condition maintained around the liquid coating bath ranges from 25oC to 100oC depending on type of the liquid coating solution used for coating.
11. The method (100) as claimed in claim 3, wherein the barbed wire bundle is rotated in vertical or horizontal position at a speed in range pf 100 rpm to 500 rpm to remove the trapped liquid during the degreasing (101), the passivating (103) and after the coating (107).
12. The method (100) as claimed in claim 1, wherein the method further comprises: the coated barbed wire bundle is subjected to temperature in range from room temperature to 180oC depending on the type of the liquid coating solution.
13. The method (100) as claimed in claim 1, wherein structure of the barbed wire is selected from single barb, double barb, conventional twist, reverse twist, single stand, and double stand.
14. The method (100) as claimed in claim 1, wherein the liquid coating solution has viscosity ranging from 1 centipoise to 100 centipoises.
15. The method (100) as claimed in claim 1, wherein the specific gravity of liquid coating solution ranges from 0.9g/ml to 1.2 g/ml.