Claims:1. A composite lining for fiber cement corrugated roofing sheet comprising: a chemically cured resinous material that is applied on a reinforced fiber with:
the grams per square meters (GSM) of the reinforced fiber being between 50 and 400; and
the weight percentage of the reinforced fiber varying between 35% and 50%; and
said chemically cured resinous material comprising:
a resin in a weight percentage that ranges between 40% and 65%;
an accelerator in a weight percentage that ranges between 0.1% and 2%;
a promoter in a weight percentage that range between 0.1% and 2%; and an initiator in a weight percentage that range between 1% and 3%.

2. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the reinforced fiber is one or a mixture of: cellulose pulp, glass fiber, carbon fiber, graphite fiber, boron fiber, high silica fiber, polyamide fiber, acrylic fiber, polyester fiber, poly para-aramid fiber, polyolefin fiber, polyvinyl alcohol fiber, and mineral fibers.

3. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the reinforced fiber is in the form of one or a combination of: mat, roving, mesh, woven or non-woven fabric, chopped strand, monofilament, branched, and unidirectional, bidirectional, or randomly oriented, which are of short length or long length.

4. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the resin is one or a mixture of: polyester resin derived from orthophthalic acid, isophthalic acid, or terephthalic acid, which contains minimum 30% by weight of styrene or acrylate as a reactive monomer; vinyl ester resin; acrylic resin; UV curable resin; and copolymers.

5. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the accelerator is one or a mixture of: potassium ocotate, barium octoate, cobalt octoate, and cobalt naphthanate.

6. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the promoter is one or a mixture of: diethyl aniline, dimethyl aniline, dimethyl-p-toluidine, and N-methylacetamide.

7. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the initiator is one or a combination of: benzyl peroxide, di-t-butyl peroxide, 2,4-dichlorobenzoyl peroxide, hydrogen peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, diisopropyl benzene hydroperoxide, acetyl acetone peroxide, tert-butyl hydroperoxide, diisopropylperoxydicarbonate, and cyclohexanone peroxide.

8. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein resinous material is applied on the reinforced fiber by: hand lay-up, spray-up, dipping, resin transfer molding, resin film infusion, resin impregnation, vacuum infusion resin transfer molding, and prepreg method.

9. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the curing of the resin after the addition of the accelerator, the promoter, and the initiator happens either at room temperature or at an elevated temperature.

10. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the curing of the resin happens through exposure to ultraviolet radiation in the presence of a photoinitiator.

11. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the reinforced fiber is coated with silanes or titanates to improve the adhesion and compatibility with matrix material.

12. The composite lining for fiber cement corrugated roofing sheet as claimed in claim 1, wherein the composite lining comprises resins of low volatile organic components from either isophthalic acid or vinyl ester resin with 35% styrene as reactive monomer.

13. A fiber cement corrugated roofing sheet with the composite lining as claimed in claim 1, for roof safety and acid resistance. , Description:TITLE OF THE INVENTION: COMPOSITE LINING FOR FIBER CEMENT CORRUGATED ROOFING SHEET

FIELD OF THE INVENTION
The present disclosure is generally related to a composite lining for fiber cement corrugated roofing sheet that improves the strength and acid resistance of the roofing sheet, and a method for manufacturing the fiber cement corrugated roofing sheet with composite lining. More particularly, the present disclosure is related to a composite lining for corrugated roofing sheet, with a fiber reinforced synthetic resin of chemically cross-linked, three-dimensional cured polymer network.
BACKGROUND OF THE INVENTION
The manufacturing of fiber cement corrugated roofing sheet using both asbestos and non-asbestos by Hatschek process is well-known in the art. However, both products available commercially have showed limitations.
The main cause for concern with fiber cement corrugated roofing sheet is its lack of safety and inferior acid resistance. Although the fiber cement corrugated roofing sheet is relatively strong, it can be easily broken under the right circumstances. Due to the presence of more cementitious material in the composition, the corrugated roofing sheets of both asbestos and non-asbestos are highly brittle in nature. As a result, the roof structure is leading to unsuccessful performance in particular situations, like stone impact, storm, hail, foot traffic, and monkey obstacles.
Further, due to their brittleness, sometimes they are unable to bear the weight of personnel during installation and maintenance. They can also suffer the effects of long-term exposure to acids, wind, and the environment.
JP2002292769 and US3415674A describe the manufacturing of composite structure for waterproofing flooring and decorative finish coating applications. However, a composite lining for corrugated roofing sheet is definitely not known. Further, it is desirable that the composite lining for the fiber cement corrugated roofing sheet shall itself exhibit at least comparable resistance to the environment.
There is, therefore, a need in the art for a composite lining for fiber cement corrugated roofing sheet that overcomes the aforementioned drawbacks and shortcomings.
OBJECTIVES OF THE INVENTION
The primary objective of the present disclosure is to provide for fiber cement corrugated roofing sheets, having an improved strength and deflection as compared to conventionally available fiber cement corrugated roofing sheets.
Another object of the present disclosure is to provide for fiber cement corrugated roofing sheets with composite lining, that aid in the protection against acids and the impact of stone, storm, hail, and the like, and also improve the safety during installation and maintenance as well.
SUMMARY OF THE INVENTION
A composite lining for fiber cement corrugated roofing sheet is disclosed. The composite lining comprises: a chemically cured resinous material that is applied on a reinforced fiber.
The grams per square meters (GSM) of the reinforced fiber range from 50 to 400, and the weight percentage of the reinforced fiber varies between 35% and 50%.
Said chemically cured resinous material comprises: a resin in a weight percentage that ranges between 40% and 65%; an accelerator in a weight percentage that ranges between 0.1% and 2%; a promoter in a weight percentage that ranges between 0.1% and 2%; and an initiator in a weight percentage that ranges between 1% and 3%.
The resinous material is applied on the reinforced fiber by: hand lay-up, spray-up, dipping, resin transfer molding, resin infusion, or impregnation.
The curing of the resin after the addition of the accelerator, the promoter, and the initiator happens either at room temperature or at an elevated temperature. Further, the curing is also possible through exposure to ultraviolet radiation in the presence of a photoinitiator.
Corrugated roofing sheet with the disclosed composite lining is stronger, along with better resistance to acids and impact, than the conventional corrugated roofing sheet without composite lining.
DETAILED DESCRIPTION OF THE INVENTION
Throughout this specification, the use of the word "comprise" and “include”, and variations such as "comprises" "comprising", “includes”, and “including” may imply the inclusion of an element or elements not specifically recited.
Throughout this specification, the disclosure of a range is to be construed as being inclusive of the lower limit of the range and the upper limit of the range.
A composite lining for fiber cement corrugated roofing sheet is disclosed. In an embodiment of the present disclosure, the composite lining comprises: a chemically cured resinous material that is applied on a reinforced fiber.
The reinforced fiber may be either organic or inorganic and natural or synthetic; for instance, cellulose pulp, glass fiber, carbon fiber, graphite fiber, boron fiber, high silica fiber, polyamide fiber, acrylic fiber, polyester fiber, poly para-aramid fiber, polyolefin fiber, polyvinyl alcohol fiber, and mineral fibers, or combination thereof.
In another embodiment of the present disclosure, the reinforced fiber is in the form of one or a combination of: mat, roving, mesh, woven or non-woven fabric, chopped strand, monofilament, branched, and unidirectional, bidirectional, and/or randomly oriented, which are of short length or long length.
In yet another embodiment of the present disclosure, the grams per square meters (GSM) of the reinforced fiber is from 50 to 400. Typically, high GSM reinforced fiber is thicker and heavier; hence, absorbs more liquid resin than lighter, low GSM reinforced fiber.
In yet another embodiment of the present disclosure, the reinforced fiber is coated with a chemical to improve the adhesion and compatibility with matrix material. For example, silanes, phosphates, and titanates are employed as sizing or coupling agents.
In yet another embodiment of the present disclosure, the weight percentage of the reinforced fiber typically varies between 35% and 50%. The type of reinforcing fiber, weight percentage, adhesion, uniform distribution of fiber with matrix, and extent of curing play a vital role in improving the strength of corrugated roofing sheets.
The chemically cured resinous material comprises: a resin in a weight percentage that ranges between 40% and 65%; an accelerator in a weight percentage that ranges between 0.1% and 2%; a promoter in a weight percentage that ranges between 0.1% and 2%; and an initiator in a weight percentage that ranges between 1% and 3%. The curing of the resin after the addition of the accelerator, the promoter, and the initiator happens either at room temperature or at an elevated temperature. Further, the curing is also possible through exposure to ultraviolet radiation in the presence of a photoinitiator.
In yet another embodiment of the present disclosure, the resin is selected from either cross-linkable thermoplastic or thermosetting materials including, but not limited to, polyester resin derived from a resin like orthophthalic acid, isophthalic acid, or terephthalic acid, which contains minimum 30% by weight of styrene or acrylate as a reactive monomer; vinyl ester resin; acrylic resin; UV curable resin; and copolymers or mixtures of the same.
In yet another embodiment of the present disclosure, the resins of low volatile organic components from either isophthalic acid or vinyl ester resin with 35% styrene as reactive monomer provide the acid resistance to the fiber cement corrugated roofing sheets.
In yet another embodiment of the present disclosure, the curable resin may be either a one component or a two component system. The viscosity, molecular weight, active solid content, and amount of functional groups decide the performance properties of the corrugated roofing sheets.
In yet another embodiment of the present disclosure, the accelerator may be selected from, for example, potassium ocotate, barium octoate, cobalt octoate, cobalt naphthanate and mixtures thereof. Heat exposure may also be required to promote the curing reactions.
In yet another embodiment of the present disclosure, the promoter may be selected from diethyl aniline, dimethyl aniline, dimethyl-p-toluidine, N-methylacetamide, and combination thereof.
In yet another embodiment of the present disclosure, the initiator may be, for example, benzyl peroxide, di-t-butyl peroxide, 2,4-dichlorobenzoyl peroxide, hydrogen peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, diisopropyl benzene hydroperoxide, acetyl acetone peroxide, tert-butyl hydroperoxide, diisopropylperoxydicarbonate, and cyclohexanone peroxide, and combinations thereof.
The composite lining is prepared by applying the chemically cured resinous material on the reinforced fiber. The method of application of the resinous material on the reinforced fiber includes, but is not limited to, hand lay-up, spray-up, dipping, resin transfer molding, resin infusion, impregnation and prepreg method.
The method of manufacturing of the fiber cement corrugated roofing sheet with the composite lining, as disclosed in the present disclosure, shall now be explained.
The conventional fiber cement corrugated roofing sheet is surface cleaned after the complete curing. The foreign or contaminated materials on the surface of the corrugated roofing sheet are removed by wiping with a fast evaporating solvent or smooth clean cloth, and then rubbing with mild emery paper to create a rough surface for better adhesion.
The composite lining is placed on the surface of the corrugated roofing sheet and then allowed to harden or cure. Different methods of application are employed for the preparation of the corrugated roofing sheet with composite lining, including, but not limited to, hand lay-up, spray-up, wet lay-up, dipping, resin transfer molding, resin film infusion, resin impregnation, vacuum infusion resin transfer molding, and prepreg method.
The cured corrugated roofing sheet with composite lining has a superior strength along with high deflection and acid resistance as compared to conventional fiber cement corrugated roofing sheets available. Examples of the composite lining composition are shown in Table 1.
Raw Material Example
1 Example
2 Example
3 Example
4
Orthophthalic acid resin 60 - - -
Isophthalic acid resin - 60 - -
Terephthalic acid resin - - 60 -
Vinyl ester resin - - 60
Cobalt octoate 0.6 0.6 0.6 0.6
Dimethyl aniline - - - 1.0
Methyl ethyl ketone peroxide 1.5 1.5 1.5 1.5
Chopped strand mat 40 40 40 40
Table 1
Various tests have been performed to prove the improved performance properties, such as parallel bending strength and load bearing capacity of the corrugated roofing sheets with composite lining.
By the way of comparison, the corrugated roofing sheet with composite lining of the present disclosure exhibit improved performance properties, such as parallel bending strength, load bearing capacity, and deflection, which are measured as per GOST 8423-57, IS 5913-89, IS 14871-00 and IS 459-92, respectively.
For parallel bending strength test, corrugated roofing sheet of about 200 mm x 300 mm (length x width) is used and for the load bearing capacity measurement about 1200 mm x 1100 mm corrugated roofing sheet is used. The constant thickness is maintained in both the cases. The measured data are shown in Table 2 and Table 3.
S. No. Sample Description Thickness (mm) Parallel Bending Strength (Kg/cm2)
1 Reference sheet 6.9 85
2 Roofing sheet with composite lining of 100 GSM fiber mat 7.0 111
3 Roofing sheet with composite lining of 200 GSM fiber mat 7.1 192
4 Roofing sheet with composite lining of 300 GSM fiber mat 7.0 190
5 Roofing sheet with composite lining of 350 GSM fiber mat 7.2 193
Table 2
The parallel bending strength comparison of the corrugated roofing sheet with composite lining of the present disclosure, with various GSM of reinforced fiber, and a reference roofing sheet are shown in Table 2. The reference roofing sheet is conventionally available non-asbestos fiber cement corrugated roofing sheet without composite lining.
It can be observed that, regardless of fiber GSM, the corrugated roofing sheet with composite lining provides higher parallel bending strength as compared to the conventional corrugated roofing sheet, i.e. reference sheet. However, corrugated roofing sheet with composite lining having the fiber with 200 GSM showed better parallel bending strength and, after that, there is no considerable change in performance properties with respect to GSM of the fiber.
S. No. Sample Description LBC
(kg) Deflection
(mm)
1 Reference - 1 550 10.5
2 Reference -1 with composite lining of 200 GSM fiber mat 710 14.1
3 Reference - 2 415 33.2
4 Reference - 2 with composite lining of 200 GSM fiber mat 630 46.5
Table 3
Table 3 shows the load bearing capacity (LBC) and deflection comparison test results of the corrugated roofing sheets with composite lining and reference corrugated roofing sheets (which are conventional fiber cement corrugated roofing sheet without composite lining).
Reference - 1 is an asbestos fiber cement corrugated roofing sheet without composite lining and Reference - 2 is non-asbestos fiber cement corrugated roofing sheets without composite lining. The results clearly indicate that the corrugated roofing sheet with composite lining significantly improves the LBC of corrugated roofing sheet irrespective of asbestos and non-asbestos fiber cement sheet.
For instance, LBC of Reference - 1 with composite lining is approximately 29% higher than that of Reference - 1. Likewise, the LBC of Reference - 2 with composite lining is approximately 52% higher than that of Reference - 2.
The deflection of corrugated roofing sheet with composite lining is also improved when compared to that of the conventional fiber cement corrugated roofing sheet without composite lining. Hence, it is clear that the corrugated roofing sheet with composite lining is stronger, along with better impact resistance, than the conventional corrugated roofing sheet without composite lining.
Further the corrugated roofing sheet with composite lining shows a minor surface cracks after LBC testing whereas the conventional corrugated sheet has been broken down on the same situation. It indicates that composite lining provides an additional load support to the corrugated roofing sheets that aids the safety during installation, maintenance and abrupt impact condition.
Generally conventional fiber cement corrugated roofing sheets have poor resistance to acids, particularly hydrochloric acid, acetic acid, nitric acid, sulphuric acid, phosphoric acid, and boric acid. However, the disclosed corrugated roofing sheets with composite lining provide better resistance to acids. This can be due to the polymer back bone and formation of highly cross-linked three-dimensional network on the composite roofing system.
It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations and improvements without deviating from the spirit and the scope of the disclosure may be made by a person skilled in the art. Such modifications, additions, alterations and improvements should be construed as being within the scope of this disclosure.