DESC:FIELD
The present disclosure relates to Fiber Reinforced Polymer (FRP) coated pre-painted profile steel sheets.
BACKGROUND
Fiber reinforced composite materials for roofing and other applications can be designed and constructed that have mechanical and physical properties such as low density, high tensile strength, and high modulus of elasticity or stiffness. However, these materials have low resistance to wear including abrasive and erosive wear, and are susceptible to oxidation and other forms of corrosion which limits their application.
The present disclosure therefore, envisages a Fiber Reinforced Polymer coating on pre-painted profile steel sheets that mitigate the drawbacks associated with the conventional coated sheets.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide a fiber reinforced polymer coated pre-painted profile steel sheet, having improved mechanical strength and resistance to corrosion.
Another object of the present disclosure is to provide a process for preparing a fiber reinforced polymer coated profile steel sheet.
Yet another object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Other objects and advantages of the present disclosure will be more apparent from the following description which is not intended to limit the scope of the present disclosure.

SUMMARY
The present disclosure envisages a fiber reinforced polymer coated pre-painted profile steel sheet that is corrosion/acid fume resistant for roofing and vertical applications. In one embodiment, at least one layer of fiber reinforced polymer coating is applied on a bottom surface of the profile steel sheet.
The present disclosure also envisages a process for making the fiber reinforced polymer coated profile steel sheet. The process for making the fiber reinforced polymer coated profile steel sheet comprises the following steps: (i) coating a layer of aluminum-zinc alloy on the top surface and the bottom surface of a steel strip to obtain an aluminum-zinc coated steel strip; (ii) applying a layer of primer and a layer of color coating on the top surface of the aluminum-zinc coated steep strip; (iii) passing the color and aluminum-zinc coated steel strip through a plurality of steel rolls having different contours to obtain a pre-painted profile steel sheet; (iv) roughening the bottom surface of the pre-painted profile steel sheet using a roughening agent to obtain a profile sheet having a roughened bottom surface; (v) applying a layer of resin coat with hardener on the pre-painted profile steel sheet having a roughened bottom surface (vi) applying a fiber mat to the resin coated pre-painted profile steel sheet to obtain a pre-painted profile steel sheet with a roughened and resin coated bottom surface on which the fiber mat is adhered; (vii) applying a second layer of liquid resin coat on the fiber reinforced coated pre-painted profile sheet, to obtain a double layer resin coated bottom surface; (viii) applying a second layer of fiber mat over the second layer of resin coat to obtain a Fiber Reinforced Polymer coated pre-painted profile steel sheet; and (ix) drying the Fiber Reinforced Polymer (FRP) coated pre-painted profile steel sheet in the open atmosphere.
In one embodiment, the aluminum-zinc alloy coating on the top surface of the steel strip has thickness in the range of 60 to 80 micron and the aluminum zinc alloy coating on the bottom surface of the steel strip has a thickness ranging from 30 to 50 micron. In another embodiment of the present disclosure, the roughening agent is any suitable roughening agent such as a grinder, an emery board, sand paper, glass paper, steel wool, grit blast, chemical treatment agents, and abrasives.
In yet another embodiment, the primer is selected from the group of epoxy, polyester, and universal primers such that the layer of the primer has a thickness of 5-7 micron and the color coating is selected from the group consisting of regular modified polyester paint, silicon modified polyester paint, and acrylic paint such that the layer of color coating applied on the top surface has a thickness of 20-25 micron.
In another embodiment of the present disclosure, each of the resin coat layer is selected from the group of isophthalic resin and polymeric epoxy resin and the hardener is cobalt catalyst hardener. In still another embodiment of the present disclosure, the fiber used is typically glass wool.
In one exemplary embodiment, the drying of the fiber reinforced polymer coated pre-painted profile steel sheet is done for 30 to 40 minutes.
DETAILED DESCRIPTION
Corrosion of the pre-painted profiled roofing steel sheets is observed due to continuous exposure to acidic fumes in the pickling line and acid re-generation plant area. The corroded roofing sheets have to be frequently replaced, resulting in operational shut down which affects the productivity. Also, the corroded roofing sheets can pose a safety threat.
The present disclosure provides fiber reinforced polymer coated profile steel sheets that are corrosion/acid fume resistant for roofing and vertical applications. The present disclosure also envisages a process for making fiber reinforced polymer coated pre-painted profile steel sheet. The FRP coating disclosed in the present disclosure is typically applied on the bottom surface of the pre-painted profile steel sheet. The process for making fiber reinforced polymer coated pre-painted profile steel sheet can include the steps disclosed herein below.
1. The top surface and the bottom surface of the steel strip are coated with a layer of aluminum-zinc alloy to obtain an aluminum-zinc coated steel strip. In one embodiment, the aluminum-zinc alloy coating on the top surface of the steel strip may have thickness in the range of 60 to 80 micron. In another embodiment, the aluminum zinc alloy coating on the bottom surface of the steel strip may have a thickness ranging from 30 to 50 micron.
2. A layer of primer and a layer of color coating are applied on the top surface of the aluminum-zinc coated steep strip. The bottom surface of the aluminum-zinc coated steep strip is not provided with primer and color coating. In one embodiment, the primer can be selected from the group of epoxy, polyester, universal primers and the like. In another embodiment, the layer of primer can have a thickness of 5-7 micron. The color coating is done on the top surface of the aluminum-zinc coated steel strip after the primer is applied to obtain a color and aluminum-zinc coated steel strip. In one embodiment, the color coating can be selected from the group consisting of regular modified polyester paint, silicon modified polyester paint, acrylic paint and the like. In another embodiment, the layer of color coating applied on the top surface can have a thickness of 20-25 micron.
3. The color and aluminum-zinc coated steel strip is then passed through a plurality of steel rolls having different contours to obtain a pre-painted profile steel sheet. In one embodiment, the profiling of the steel strip is done at a profiling line. In another embodiment, the pre-painted profile steel sheet can be trapezoidal in shape. The color and aluminum-zinc coated steel strip is cut to obtain the pre-painted profile steel sheet.
4. Roughening of the bottom surface of the pre-painted profile steel sheet is done using a roughening agent to obtain a profile sheet having a roughened bottom surface. In one embodiment, the roughening agent is typically a grinder so as to provide a strong bonding of fiber reinforced polymer with base metal. In another embodiment, the roughening agent is any suitable roughening agent that can be selected from the group consisting of a grinder, emery board, sand paper, glass paper, steel wool, grit blast, chemical treatment agents, and abrasives.
5. Next, a layer of resin coat is applied on the pre-painted profile sheet having a roughened bottom surface to obtain a resin coated bottom surface. In one embodiment, the resin coat may be selected from the group of isophthalic resin, polymeric epoxy resin and the like. In another embodiment, the resin is mixed with a hardener before applying it on the pre-painted profile sheet having a roughened bottom surface. In an exemplary embodiment, the hardener can be a cobalt catalyst hardener.
6. In the next step, a fiber mat is applied to the resin coated layer to obtain a pre-painted profile steel sheet with a roughened bottom surface on which the fiber mat is adhered. In one embodiment, the fiber used is typically glass wool. In another embodiment, the fiber can be natural or synthetic fiber. In yet another embodiment, the fiber can be selected from the group consisting of jute, coconut coir/fiber, polyester, silk and the like.
7. In the next step, a second layer of resin coat is applied on the pre-painted profile sheet having a roughened and resin coated bottom surface on which the fiber mat is adhered to, to obtain a double layer resin coated bottom surface. In one embodiment, the second layer of resin coat may be selected from the group of isophthalic resin, polymeric epoxy resin and the like. In another embodiment, the second layer of resin is also mixed with a hardener before applying it on the pre-painted profile sheet having a roughened bottom surface. The mixture of resin and hardener may act as an adhesive layer.
8. In the next step, a second layer of fiber mat is applied over the second layer of resin coat to obtain a Fiber Reinforced Polymer (FRP) coated pre-painted profile steel sheet. In one embodiment, the second layer of fiber used is typically glass wool. In another embodiment, the second layer of fiber can be natural or synthetic fiber. In yet another embodiment, the second layer of fiber can be selected from the group consisting of jute, coconut coir/fiber, polyester, silk and the like.
9. After the step 9, the Fiber Reinforced Polymer (FRP) coated pre-painted profile steel sheet is dried in open atmosphere for around 30 to 40 minutes in the open atmosphere to achieve complete bonding.
The application of the different layers to the bottom surface of the profile steel sheet in accordance with the present disclosure can be manual or automated. In one embodiment, the fiber reinforced polymer coated pre-painted profile steel sheet is made with different FRP colors with the use of Pigments and the like. In another embodiment, further modification in the design of the roofing sheets with respect to the use of natural source of light.
The Fiber Reinforced Polymer coating on the bottom surface of the profile steel sheet in accordance with the present disclosure increases the life of the colour coated profile steel sheet under corrosive/acid fume conditions. The Fiber Reinforced Polymer layers are reduced to about 0.9 to 1mm thickness from the conventional pure Fiber Reinforced Polymer layer of about 3mm resulting in reduced cost. The Fiber Reinforced Polymer (FRP) coated profile steel sheet also has improved mechanical strength. The FRP coated profile steel sheet can be used for roofing and vertical application. The anti-corrosive property of the FRP coat combined with the strength of the steel sheet results in enhanced safety and sustainability.
TECHNICAL ADVANCEMENTS
-The present disclosure provides a fiber reinforced polymer coated pre-painted profile steel sheet which is corrosion/acid fume resistant and is used for roofing and vertical applications.
-The present disclosure also provides a fiber reinforced polymer (FRP) coating on a pre-painted profile steel sheet having reduced thickness as compared to conventional FRP resulting in significant cost reduction.
The exemplary embodiment herein quantifies the benefits arising out of this disclosure and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:1. A fiber reinforced polymer coated pre-painted profile steel sheet that is corrosion/acid fume resistant for roofing and vertical applications.
2. The fiber reinforced polymer coated pre-painted profile steel sheet as claimed in claim 1, wherein at least one layer of fiber reinforced polymer coating is applied on a bottom surface of the profile steel sheet.
3. A process for making fiber reinforced polymer coated pre-painted profile steel sheet, comprising the following steps:
a. coating a layer of aluminum-zinc alloy on the top surface and the bottom surface of a steel strip to obtain an aluminum-zinc coated steel strip;
b. applying a layer of primer and a layer of color coating on the top surface of the aluminum-zinc coated steel strip;
c. passing the color and aluminum-zinc coated steel strip through a plurality of steel rolls having different contours to obtain a pre-painted profile steel sheet;
d. roughening the bottom surface of the pre-painted profile steel sheet using a roughening agent to obtain a profile sheet having a roughened bottom surface;
e. applying a layer of resin coat with hardener on the pre-painted profile steel sheet having a roughened bottom surface to obtain a resin coated bottom surface;
f. applying a fiber mat to the resin coated layer to obtain a pre-painted profile steel sheet with a roughened and resin coated bottom surface on which the fiber mat is adhered;
g. applying a second layer of resin coat on the fiber reinforced coated pre-painted profile sheet, to obtain a double layer resin coated bottom surface;
h. applying a second layer of fiber mat over the second layer of resin coat to obtain a Fiber Reinforced Polymer coated pre-painted profile steel sheet; and
i. drying the Fiber Reinforced Polymer (FRP) coated pre-painted profile steel sheet in the open atmosphere.
4. The process for making fiber reinforced polymer coated pre-painted profile steel sheet, as claimed in claim 3, wherein the aluminum-zinc alloy coating on the top surface of the steel strip has thickness in the range of 60 to 80 micron and the aluminum zinc alloy coating on the bottom surface of the steel strip has a thickness ranging from 30 to 50 micron.
5. The process for making fiber reinforced polymer coated pre-painted profile steel sheet, as claimed in claim 3, wherein the roughening agent is any suitable roughening agent such as a grinder, an emery board, sand paper, glass paper, steel wool, grit blast, chemical treatment agents, and abrasives.
6. The process for making fiber reinforced polymer coated pre-painted profile steel sheet, as claimed in claim 3, wherein the primer is selected from the group of epoxy, polyester, and universal primers such that the layer of the primer has a thickness of 5-7 micron.
7. The process for making fiber reinforced polymer coated pre-painted profile steel sheet, as claimed in claim 3, wherein the color coating is selected from the group consisting of regular modified polyester paint, silicon modified polyester paint, and acrylic paint such that the layer of color coating applied on the top surface has a thickness of 20-25 micron.
8. The process for making fiber reinforced polymer coated pre-painted profile steel sheet, as claimed in claim 3, wherein each of the resin coat layer is selected from the group of isophthalic resin and polymeric epoxy resin and the hardener is cobalt catalyst hardener.
9. The process for making fiber reinforced polymer coated pre-painted profile steel sheet, as claimed in claim 3, wherein the fiber used is typically glass wool.
10. The process for making fiber reinforced polymer coated pre-painted profile steel sheet, as claimed in claim 3, wherein the drying of the fiber reinforced polymer coated pre-painted profile steel sheet is done for 30 to 40 minutes.