The present disclosure relates to the development of coating materials for application on articles/substrates. A coating material comprising cycloalkyl amine based curing agent and epoxy acrylate based resin is provided by the present disclosure. Said coating material/composition is breathable as it is impermeable to water but possess enough permeability to evaporate the water vapor. Further, the present coating material/composition possesses excellent mechanical and chemical properties when applied onto steel framed structural/construction articles.

BACKGROUND OF THE DISCLOSURE
Concretes are utilized in reinforced concrete bridges/dams/buildings/floors due to its versatility. As a material, concrete works well in compression, but it has less resistance in tension. Steel, however, is very strong in tension, even when used only in relatively small amounts. Steel framed concrete means concrete which is reinforced by steel structures. In particular, steel framed concretes use concrete's compressive strength alongside steel's resistance to tension, and when tied together this results in a highly efficient and lightweight unit that is commonly used for structures such as multi-storey buildings and bridges. However, corrosion is a major problem in reinforcing concretes with steel structures. This is majorly due to the moisture content which limits gaseous diffusion such as oxygen, chlorides and carbon dioxide ingression. Therefore, surface treatment/coating is needed for limiting the penetration of water and injurious substances into concrete. However, this does not remove intrinsic problems within the concrete itself such as alkali silica reaction and calcium chloride contamination.

The currently available surface coatings provide resistance to water in its liquid state. Mostly, the impermeable coatings such as silane based hydrophobic coatings resist the ingress of carbon dioxide, chloride ions and provide a barrier to water vapor. There is another class of penetrant materials such as epoxy resin impregnation or crystal growth materials whose action is to block the pores of the concrete. The former requires expensive provisions to get adequate penetration while the latter is yet to be proved as effective. But if these type of coatings are applied by keeping the concrete in a less saturated condition, it will allow to carbonate faster. However, corrosion is likely to occur even in the drier concretes. Further, impermeable materials have been achieved which are less vulnerable to weathering as they are present below the surface of the concrete. However, complete impermeability to water vapor can lead to failure of the coating because loss of adhesion of water vapor pressures can build up behind the coating. Also, evaporation of water can leave behind salts at the interface of the coating and the concrete, and freezing of water trapped behind the coating can cause loss of adhesion. Further, concretes crack under load due to shrinkage and thermal movements. Therefore, elasticity is a desirable property allowing the coating to bridge the cracks. Moreover, if the surface coating has a different temperature coefficient compared to the concrete, then it can be a severe failure.

Water vapor permeance (breathability) is generally considered as a desirable quality in a coating as it allows moisture in the concrete to escape. Particularly, breathable coatings contain several pores that are too small to allow water/rain droplets and wind to pass through, but large enough to evaporate water vapor/moisture. Further, breathable coating contains elasticity to prevent cracks generated through shrinkage and temperature variations. Breathable coatings/systems are very much useful for damp surfaces as well. Such coatings bond with the damp substrate and the new concrete upon four or five days of curing, thus making it unique. However, most of the epoxy resin based coatings are impermeable to water vapor/moisture and can fail if applied to damp substrates or to slabs with high moisture-vapor emission rates.

Accordingly, there is a need in the art to develop breathable coatings which are permeable to water vapor but impermeable to water/rain droplets, for application on to steel framed concretes in order to avoid cracking and poor adhesion, and further possessing enhanced corrosion resistance and mechanical properties, thereby addressing the aforesaid drawbacks.

STATEMENT OF THE DISCLOSURE
The present disclosure relates to a coating composition comprising a curing agent and a resin, wherein the curing agent comprises cycloalkyl amine or a substituted cycloalkyl amine thereof, and the resin comprises epoxy acrylate, and wherein the curing agent and resin is present at a ratio of about 3:5 to 5.5:5.

The disclosure further relates to a method for preparing the coating composition as described above, comprising:
a) preparing the curing agent and the resin, and
b) mixing the curing agent and the resin at a ratio of about 3:5 to 5.5:5, to obtain the coating composition.

The present disclosure also relates to coated article comprising the coating composition as described above, and a method of preparing said coated article comprising:
a) preparing the coating composition according to the method described above, and
b) applying the coating composition onto the article and curing for a time-period of about 6 to 8 hours at a temperature of about 25 ? to 30 ?, to obtain the coated article.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1 depicts FT-IR results of the breathable coating composition of the present disclosure.
Figure 2 depicts XRD results of the breathable coating composition of the present disclosure.
Figure 3 depicts salt spray test results of the present breathable coating composition in 5 wt. % NaCl aqueous solution.

DETAILED DESCRIPTION OF THE DISCLOSURE
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” or “containing” or “has” or “having” wherever used, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

As used herein, the term ‘curing agent’ refers to a mixture or blend of components primarily comprising cycloalkyl amine or substituted cycloalkyl amine thereof. In an embodiment, the ‘curing agent’ is a mixture or blend comprising cycloalkyl amine or substituted cycloalkyl amine thereof along with one or more agents selected from thixotropic or anti-settling agent, anti-crater agent, levelling agent, wetting agent, defoamer, opacifier and filler. In another embodiment, the ‘curing agent’ comprises a cycloalkyl amine or a substituted cycloalkyl amine thereof, a thixotropic or anti-settling agent, an anti-crater agent, levelling agent or wetting agent, a defoamer, an opacifier, filler(s) and optionally, water.

As used herein, the term ‘resin’ refers to a mixture or blend of components primarily comprising epoxy acrylate and viscosity reducing agent. In an embodiment, the ‘resin’ is a mixture or blend comprising bisphenol dimethacrylates and a viscosity reducing agent.

The present disclosure is in relation to the development of coating material for application on steel based structural/construction articles. An object of the present disclosure is to develop a breathable coating material/composition possessing: (i) excellent breathability possessing water vapor permeance; (ii) improved mechanical and chemical properties when applied on steel framed structural/construction articles, especially steel framed concretes (SFCs); and (iii) improved anti-rust and humidity prevention even in wet/damp/uncleaned surfaces of steel framed structural/construction articles, especially steel framed concretes.

Accordingly, a unique two component water based and volatile organic compound (VOC) free epoxy acrylate-cycloalkyl amine based coating material/composition is developed in the present disclosure to avoid cracking and poor adhesion along with possessing excellent chemical and mechanical properties when applied on to steel framed articles. Said coating material/composition of the present disclosure is called breathable coating as it is impermeable to water but possess enough permeability to evaporate the water vapor. The coating material inhibits corrosion, acid or alkali attack, and improves mechanical properties such as tensile strength, scratch hardness, abrasion and adhesion of articles including steel framed concrete structures. Additionally, the present coating material provides breathability and a foundation for top coat of epoxy and polyurethane on the coated article.

The present disclosure particularly relates to a coating composition comprising a curing agent and a resin, wherein the curing agent comprises cycloalkyl amine or a substituted cycloalkyl amine thereof, and the resin comprises epoxy acrylate, and wherein the curing agent and resin is present at a ratio of about 3:5 to 5.5:5.

In an embodiment of the disclosure, the curing agent of the present coating composition is a mixture comprising cycloalkyl amine, thixotropic or anti-settling agent, anti-crater agent, levelling agent, wetting agent, defoamer, opacifier and filler.

In another embodiment of the disclosure, the cycloalkyl amine or the substituted cycloalkyl amine of the present coating composition is cycloheptane amine or a substituted cycloheptane amine; and wherein the substituted cycloheptane amine is selected from a group comprising 5-amino-3-ethyl-1,3-dimethyl cycloheptane ethylamine, 5-amino-1-ethyl-3,3-dimethyl cycloheptane ethylamine, 4-amino-3-ethyl-1,6-dimethyl cycloheptane ethylamine, and combinations thereof.

In yet another embodiment of the disclosure, the thixotropic or anti-settling agent is modified solution of urea, organophilic phyllosilicates, or a combination thereof; the anti-crater agent, levelling agent or wetting agent is selected from a group comprising pre-neutralized fluorocarbon modified poly-acrylic; the defoamer is selected from a group comprising organically modified polysiloxane, silicone based agent and combination thereof; the opacifier is selected from a group comprising rutile titanium dioxide, anatase titanium dioxide and combination thereof; and the filler is selected from a group comprising calcite, barytes, silica 300 mesh and combinations thereof.

In still another embodiment of the disclosure, the curing agent comprises cycloalkyl amine or substituted cycloalkyl amine at a concentration ranging from about 15 to 25 wt%, the thixotropic or anti-settling agent at a concentration ranging from about 0.5 to 1.5 wt%, the anti-crater agent, levelling agent or wetting agent at a concentration ranging from about 0.3 to 0.5 wt%, the defoamer at a concentration ranging from about 0.5 to 1.5 wt%, the opacifier at a concentration ranging from about 3 to 15 wt%, and the filler at a concentration ranging from about 30 to 65 wt%.

In still another embodiment of the disclosure, the curing agent comprises cycloheptane amine or substituted cycloheptane amine at a concentration ranging from about 15 to 25 wt%, modified solution of urea at a concentration ranging from about 0.5 to 1.5 wt%, pre-neutralized fluorocarbon modified poly-acrylic at a concentration ranging from about 0.3 to 0.5 wt%, organically modified polysiloxane at a concentration ranging from about 0.5 to 1.5 wt%, titanium dioxide at a concentration ranging from about 3 to 15 wt%, and fillers comprising calcite at a concentration ranging from about 15 to 45 wt%, silica 300 mesh at a concentration ranging from about 15 to 45 wt% and barytes at a concentration ranging from about 3 to 10 wt%.

In still another embodiment of the disclosure, the resin of the present coating composition is a mixture comprising epoxy acrylate and viscosity reducing agent.

In still another embodiment of the disclosure, the epoxy acrylate is bisphenol dimethacrylate selected from bisphenol A dimethacrylate, bisphenol F dimethacrylate, or a combination thereof, preferably a combination of bisphenol A dimethacrylate and bisphenol F dimethacrylate; and the viscosity reducing agent is mono-glycidyl ether of fatty alcohol, preferably mono-glycidyl ether of C-14 fatty alcohol.

In still another embodiment of the disclosure, the resin comprises the epoxy acrylate at a concentration ranging from about 60 to 80 wt.%, and the viscosity reducing agent at a concentration ranging from about 20 to 40 wt.%.

In still another embodiment of the disclosure, the resin comprises bisphenol A dimethacrylate at a concentration ranging from about 30 to 40 wt%, bisphenol F dimethacrylate at a concentration ranging from about 30 to 40 wt%, and mono-glycidyl ether of fatty alcohol at a concentration ranging from about 20 to 40 wt%.

In still another embodiment of the disclosure, the present coating composition comprises a curing agent mixture and a resin mixture; wherein the curing agent mixture comprises cycloalkyl amine at a concentration ranging from about 15 to 25 wt%, thixotropic or anti-settling agent at a concentration ranging from about 0.5 to 1.5 wt%, anti-crater agent, levelling agent or wetting agent at a concentration ranging from about 0.3 to 0.5 wt%, defoamer at a concentration ranging from about 0.5 to 1.5 wt%, the opacifier at a concentration ranging from about 3 to 15 wt%, and the filler at a concentration ranging from about 30 to 65 wt%, and the resin mixture comprises epoxy acrylate at a concentration ranging from about 60 to 80 wt%, and viscosity reducing agent at a concentration ranging from about 20 to 40 wt%; and wherein said curing agent mixture and the resin mixture is present in the composition at a ratio of about 3:5 to 5.5:5.

In still another embodiment of the disclosure, the present coating composition comprises a curing agent mixture and a resin mixture; wherein the curing agent mixture comprises cycloheptane amine or substituted cycloheptane amine at a concentration ranging from about 15 to 25 wt%, modified solution of urea at a concentration ranging from about 0.5 to 1.5 wt%, pre-neutralized fluorocarbon modified poly-acrylic at a concentration ranging from about 0.3 to 0.5 wt%, organically modified polysiloxane at a concentration ranging from about 0.5 to 1.5 wt%, titanium dioxide at a concentration ranging from about 3 to 15 wt%, and fillers comprising calcite at a concentration ranging from about 15 to 45 wt%, silica 300 mesh at a concentration ranging from about 15 to 45 wt% and barytes at a concentration ranging from about 3 to 10 wt%, and the resin mixture comprises bisphenol A dimethacrylate at a concentration ranging from about 30 to 40 wt%, bisphenol F dimethacrylate at a concentration ranging from about 30 to 40 wt%, and mono-glycidyl ether of C-14 fatty alcohol at a concentration ranging from about 20 to 40 wt%; and wherein said curing agent mixture and the resin mixture is present in the composition at a ratio of about 4:5

The disclosure further relates to a method for preparing the coating composition as described above, comprising:
a) preparing the curing agent and the resin, and
b) mixing the curing agent and the resin at a ratio of about 3:5 to 5.5:5, to obtain the coating composition.

In an embodiment of the method described above, the curing agent is a mixture comprising cycloalkyl amine or substituted cycloalkyl amine at a concentration ranging from about 15 to 25 wt%, thixotropic or anti-settling agent at a concentration ranging from about 0.5 to 1.5 wt%, anti-crater agent, levelling agent or wetting agent at a concentration ranging from about 0.3 to 0.5 wt%, defoamer at a concentration ranging from about 0.5 to 1.5 wt%, the opacifier at a concentration ranging from about 3 to 15 wt%, and filler at a concentration ranging from about 30 to 65 wt%, and the resin is a mixture comprising epoxy acrylate at a concentration ranging from about 60 to 80 wt%, and viscosity reducing agent at a concentration ranging from about 20 to 40 wt%.

In another embodiment of the method described above, the curing agent is a mixture comprising cycloheptane amine or substituted cycloheptane amine at a concentration ranging from about 15 to 25 wt%, modified solution of urea at a concentration ranging from about 0.5 to 1.5 wt%, pre-neutralized fluorocarbon modified poly-acrylic at a concentration ranging from about 0.3 to 0.5 wt%, organically modified polysiloxane at a concentration ranging from about 0.5 to 1.5 wt%, titanium dioxide at a concentration ranging from about 3 to 15 wt%, and fillers comprising calcite at a concentration ranging from about 15 to 45 wt%, silica 300 mesh at a concentration ranging from about 15 to 45 wt% and barytes at a concentration ranging from about 3 to 10 wt%, and the resin is a mixture comprising bisphenol A dimethacrylate at a concentration ranging from about 30 to 40 wt%, bisphenol F dimethacrylate at a concentration ranging from about 30 to 40 wt%, and mono-glycidyl ether of C-14 fatty alcohol at a concentration ranging from about 20 to 40 wt%.

In yet another embodiment of the method described above, the curing agent mixture is prepared by adding the cycloalkyl amine or substituted cycloalkyl amine, the thixotropic or anti-settling agent, the anti-crater agent, levelling agent or wetting agent, the defoamer, the opacifier, the filler and water in a homogenizer, and grinding for a time-period of about 45 to 60 minutes.

In still another embodiment of the method described above, the resin mixture is prepared by blending epoxy acrylate and viscosity reducing agent, preferably bisphenol A dimethacrylate, bisphenol F dimethacrylate and mono glycidyl ether of C-14 fatty alcohol at a ratio of about 2:2:1 in a reactor at a temperature of about 55? to 65? and time-period ranging from about 30 minutes to 45 minutes.

In still another embodiment of the method described above, the curing agent and the resin are mixed at a ratio of about 4:5, 3:5, 5:5 or 5.5:5, preferably 4:5; and wherein induction or incubation period after mixing ranges from about 1 minutes to 2 minutes, preferably 2 minutes.

The present disclosure also relates to coated article comprising the coating composition as described above, and a method of preparing said coated article comprising:
a) preparing the coating composition according to the method described above, and
b) applying the coating composition onto the article and curing for a time-period of about 6 to 8 hours at a temperature of about 25 ? to 30 ?, to obtain the coated article.
In an embodiment of the disclosure, the coated article is a steel framed concrete (SFC) coated with the coating composition as described above.

The disclosure further provides a method of preparing a coated article comprising the present coating composition, comprising:
a) preparing the coating composition according to the method as described herein; and
b) applying the coating composition on to the article and curing for a time-period of about 6 to 8 hours at a temperature of about 25 ? to 30 ?, to obtain the coated article.

Thus, according to the present disclosure, there is provided a uniform, stabilized and VOC-free breathable coating for application on to steel based structural/construction articles such as steel framed concrete (SFC) slabs including but not limiting to concrete roof water proofing, cooling towers, concrete bridge and tanks, basements, dams, irrigation, tunnels, subways, chemical processing plants, marine, offshore cooling towers or platforms.

In an exemplary embodiment of the present disclosure, the breathable coating composition is developed by:
a) preparing curing agent mixture by:
i) providing cycloheptane amine or substituted cycloheptane amine; modified solution of urea as a thixotropic/anti-settling agent; pre-neutralized fluorocarbon modified poly-acrylic in water as an anti-crater, levelling, hydrophobic and wetting agent; organically modified polysiloxane as a defoamer for high shear application; titanium dioxide for good opacity; and fillers including calcite, barytes and silica 300 mesh,
ii) adding all components of step i) except fillers into a bead mill or a similar homogenizer,
iii) grinding for about 15 minutes with a high shear rate,
iv) adding fillers and continuing grinding for about 45 minutes, wherein demineralized water is additionally added for good shearing;

b) preparing resin mixture by: providing epoxy acrylate resin by preparing a blend of Bisphenol A dimethacrylate with Bisphenol F dimethacrylate and mono-glycidyl ether of C14 fatty alcohol at about 2:2:1 ratio in a reactor at temperature of about 600C temperature;

and

c) mixing of curing agent mixture of step (a) and resin mixture of step (b) at a ratio of about 3:5 to 5.5:5, preferably about 4:5, for a time-period of about 1 minute to 2 minutes, preferably 2 minutes, to obtain the coating composition.

In an embodiment, the substituted cycloheptane amine employed in the preparation of curing agent in the present disclosure is as shown below (Formula A):

Formula A
wherein, R1, R3, R5 and R6 is independently an alkyl group,
R2 is alkylamine group, and
R4 is amine.

In another embodiment, R1, R3, R5 and R6 is independently a methyl group or a ethyl group; R2 is ethylamine group; and R4 is amine, in the Formula A described above.

In an exemplary embodiment, the substituted cycloheptane amine employed in the present disclosure is selected from 5-amino-3-ethyl-1,3-dimethyl cycloheptane ethylamine (Formula A1), 5-amino-1-ethyl-3,3-dimethyl cycloheptane ethylamine (Formula A2), 4-amino-3-ethyl-1,6-dimethyl cycloheptane ethylamine (Formula A3), or any combination thereof.

Formula A1 Formula A2 Formula A3

In an embodiment, the molecular weight of Bisphenol A dimethacrylate is 364.43 g/mol and has the formula [H2C=C(CH3)CO2C6H4]2C(CH3)2 as shown below (Formula B):

Formula B
In another embodiment, the molecular weight of Bisphenol F dimethacrylate is 336.43 g/mol and has the formula [H2C=C(CH3)CO2C6H4]2CH2 as shown below (Formula C):

Formula C

In an embodiment of the present disclosure, the bisphenol A dimethacrylate is synthesized by reacting bisphenol A diglycidyl ether and acrylic acid at a ratio of about 1.4:1 in the presence of a nitrogen base catalyst at a temperature of about 100? for about 4 hours. In another embodiment, any known method of synthesizing bisphenol A dimethacrylate can be employed in the present disclosure.

In another embodiment of the present disclosure, the bisphenol F dimethacrylate is synthesized by reacting bisphenol F diglycidyl ether and acrylic acid at a ratio of about 1.4:1 in the presence of a nitrogen base catalyst at a temperature of about 100? for about 4 hours. In another embodiment, any known method of synthesizing bisphenol F dimethacrylate can be employed in the present disclosure.

In an exemplary embodiment, the present coating composition comprises the following curing agent and resin at a ratio of 4:5, respectively:
Curing Agent mixture -
a) 5-amino-3-ethyl-1,3-dimethyl cycloheptane ethylamine; 5-amino-1-ethyl-3,3-dimethyl cycloheptane ethylamine; or 4-amino-3-ethyl-1,6-dimethyl cycloheptane ethylamine, either individually or in any combination thereof: 20 wt%
b) Modified solution of urea (eg. BYK 420): 0.5 wt%,
c) Pre-neutralized fluorocarbon modified polyacrylic (eg. AFCONA 3570): 0.5 wt%,
d) Organically modified polysiloxane (eg. AFCONA 2503): 0.5 wt%,
e) Titanium dioxide: 5 wt%,
f) Calcite: 28 wt%,
g) Silica: 28 wt%,
h) Barytes: 4 wt%, and
i) Demineralized (DM) water: 13.5 wt. %
Resin mixture -
a) Bisphenol A dimethacrylate: 40 wt%,
b) Bisphenol F dimethacrylate: 40 wt%, and
c) mono-glycidyl ether of fatty alcohol (eg. EPOTEC RD 108): 20 wt%.

In an embodiment of the present disclosure, the epoxy acrylate resin mixture provides adherent and levelled film on the substrate/article upon curing with the curing agent mixture.

In another embodiment of the present disclosure, the pot life of the coating composition is around 30 minutes at about 250C and can be applied onto the substrate/article within 30 minutes. In an exemplary embodiment, the specific gravity of the present coating composition is about 1.5 ± 0.10.

In an embodiment of the present disclosure, the present coating composition/solution is applicable on any kind of surface including prepared or non-prepared concrete, especially steel framed concrete. Said application includes applying the present coating composition by rolling, spraying and brushing for preventing water seepage, inhibiting corrosion, acid & alkali attack and to improve the tensile strength, hardness, scratch resistance, abrasion and adhesion and to also provide the good adhesion for a top/final coat of epoxy and polyurethane onto the substrate/article coated with the present composition.

In an exemplary embodiment of the present disclosure, a coated steel framed article, preferably a coated steel framed concrete comprising the present coating composition is developed by:
a) preparing the coating composition as described above;
b) applying said coating composition to the article via. bristle brush, roller, spray or any similar application device; and
c) curing for a time-period of about 6 hours to 8 hours at a temperature of about 25? to 30?, preferably about 27? to allow evaporation of water and formation of a film, to obtain the coated article.

In yet another exemplary embodiment, the method of preparing the present coating composition and a coated article comprises the following: synthesizing curing agent (PART B) by adding about 15-25 wt% of substituted cycloheptane amine selected from 5-amino-3-ethyl-1,3-dimethyl cycloheptane ethylamine [amine hydroxyl equivalent weight (AHEW): 54 g/eq], 5-amino-1-ethyl-3,3-dimethyl cycloheptane ethylamine or 4-amino-3-ethyl-1,6-dimethyl cycloheptane ethylamine with 0.5-1.5 wt% modified solution of urea, a mixture of 0.3-0.5 wt% pre-neutralized fluorocarbon modified polyacrylic and 0.3-0.5 wt% organically modified polysiloxane, 3-15 wt% titanium dioxide, and a mixture of 15-45 wt% calcite, 15-45 wt% silica 300 mesh, 3-10 wt% barytes at ratio of about 9:9:1 and the remaining portion comprising demineralized water. In an embodiment, all the fillers including the mixture of 15-45 wt% calcite, 15-45 wt% silica 300 mesh, 3-10 wt% barytes are responsible to decide the desired permeability of the coating. Synthesis of said curing agent (PART B) is carried out for a time-period of about 60 minutes in a bead mill. The curing agent is thereafter mixed with resin (PART A) at a ratio of about 3:5 to 5.5:5 wherein said resin is a epoxy acrylate resin mixture prepared in a reactor by blending of bisphenol A dimethacrylate with bisphenol F dimethacrylate and mono-glycidyl ether of C-14 fatty alcohol at a ratio of about 2:2:1 at a temperature of about 60? and a time-period of about 2 hours to obtain the present coating composition. In an exemplary embodiment, the epoxy acrylate resin is prepared by blending about 30-40 wt% of Bisphenol F dimethacrylate [prepared by reacting Bisphenol F diglycidyl ether with Acrylic acid in about 1.4:1 ratio in the presence of N base catalyst (eg. triethylamine) at about 1000C for about 4 hours], 30-40 wt% of Bisphenol A dimethacrylate [prepared by reacting Bisphenol A diglycidyl ether with acrylic acid in about 1.4:1 ratio in the presence of N base catalyst (eg. triethylamine) at about 1000C for about 4 hours] and 15-20 wt% of mono-glycidyl ether of C-14 fatty alcohol at about 600C for about 2 hours in a reactor. In an embodiment, the mono-glycidyl ether of C-14 fatty alcohol is employed to lower the viscosity of epoxy resins. Said component increases the pot life of the curing resin, provides better non-yellowing characteristics and excellent levelling properties of the final composition. Before application of the coating composition, the composition is left for about 2 minutes. Thereafter, the coating composition is applied on to the article and cured for a time-period of about 6 hours to 8 hours at a temperature of about 27?.

In an exemplary embodiment, PART B [curing agent - amine hydroxyl equivalent weight (AHEW): 54) and PART A [epoxy acrylate resin - Epoxy Equivalent Weight (EEW): 335] is mixed at a ratio of about 4:5 by weight.

In another embodiment, the concentration of curing agent ranges between 15-25 wt% and the corresponding AHEW value of the curing agent is between 216 to 360. Accordingly, the mixing ratio of curing agent:resin is in the range of about 3:5 to 5.5:5.

In an embodiment, the following function/advantages are achieved by the components of the resin (PART A): the acrylic acid with bisphenol A/F diglycidyl ethers employed for the synthesis of bisphenol A dimethacrylate and bisphenol F dimethacrylate provide additional elasticity to the coating formulation which is needed to prevent cracks generated through shrinkage and temperature variations. In particular, the ethers viz. bisphenol A diglycidyl ether and bisphenol F diglycidyl ether have been modified into acrylates to make waterborne solutions. Moreover, both acrylates (bisphenol A dimethacrylate and bisphenol F dimethacrylate) combine together to increase the chemical resistance, temperature resistance, durability and flexibility of the final product/article. Further, as described above, both acrylates are diluted by reactive diluent (viscosity reducing agent) and used for lowering the viscosity of the final resin mixture. More particularly, said viscosity reducing agent such as mono-glycidyl ether of fatty alcohol increases the pot life of the resin mixture, provides better non-yellowing characteristics and excellent levelling properties of the coating formulation. Furthermore, since the above described epoxy resin employed in the present coating composition is more flexible, a more flexible curing agent (cycloheptane ethylamine or substituted cycloheptane ethylamine based curing agent) is employed to cure accordingly.

In another embodiment, the following function/advantages are achieved by the components of the curing agent (PART B): substituted or unsubstituted cycloheptane ethylamine with a modified solution of urea provides thixotropy for preventing settling, substituted or unsubstituted cycloheptane ethylamine with pre-neutralized fluorocarbon modified polyacrylic in water provides anti-crater, levelling and wetting properties, substituted or unsubstituted cycloheptane ethylamine with organically modified poly siloxane provides defoaming, titanium dioxide provides high refraction index and hiding. Further, fillers calcite, barytes and silica 300 mesh provide high alkali resistance, acid resistance, and elasticity.

In an embodiment of the present disclosure, if the surface of the steel framed article (eg. steel framed concrete) is rough, then the application of the present coating composition is carried out by:
a) applying a first coat of about 100 micron of dry film thickness (DFT), and
b) applying a second coat of about 100 micron DFT.

The present disclosure also provides industrial application of the present breathable coating composition. In an embodiment, the present coating composition is employed on steel framed structures including but not limiting to steel framed concrete, masonry and any kind of concrete surfaces such as Ultra-High Performance Concrete (UHPC), WJ, power tool cleaning, dry blasting, wet abrasive blasting. The present coating composition when applied onto the steel framed structures inhibits corrosion, acid, alkali attack and improves the tensile strength, hardness, scratch resistance, abrasion and adhesion of the steel framed structures. In addition, the present coating composition provides breathability and foundation for top coat of epoxy and polyurethane in the article coated with the present composition.

The present disclosure further provides characterization and analysis of properties of the coating composition described herein.

In an embodiment of the present disclosure, the liquid properties of the present coating composition including specific gravity and pot life are 1.5±0.10 and 30 minutes at room temperature, respectively. In another embodiment of the present disclosure, the characterization of fluid and its mechanism is analysed by FT-IR (Fourier transform-Infrared spectroscopy). In yet another embodiment of the present disclosure, film characterization is analysed by X-ray diffraction (XRD), chemical resistance test, taber abrasion test, tensile strength test, scratch resistance test, salt spray test, pull off adhesion test, and, hardness and wet cup test for breathability.

In an embodiment, the foregoing descriptive matter is illustrative of the disclosure and not a limitation. 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. 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.

EXAMPLES
Preparation of coating composition, Characterization and Analysis of properties
A coating composition was prepared for application onto steel framed concrete (SFC) slab. The composition was obtained by preparing curing agent comprising adding about 20 wt% of 5-amino-3-ethyl-1,3-dimethyl cycloheptane ethylamine with about 0.5 wt% modified solution of urea (BYK 420), mixture of about 0.5 wt% pre-neutralized fluorocarbon modified poly-acrylic and about 0.5 wt% organically modified poly-siloxane, about 5 wt% titanium dioxide and about 28 wt% calcite, about 28 wt% silica 300 mesh, and about 4 wt% barytes. The remaining portion comprised of demineralized water. Said curing agent mixture (PART B) was synthesized in bead mill for about 60 minutes.

Epoxy acrylate resin (PART A) was obtained by blending of Bisphenol A dimethacrylate [prepared by reacting Bisphenol A diglycidyl ether and Acrylic acid at about 1.4:1 ratio in the presence of N base catalyst at about 1000C for about 4 hours], Bisphenol F dimethacrylate [prepared by reacting Bisphenol F diglycidyl ether and Acrylic acid at about 1.4:1 ratio in the presence of N base catalyst at about 1000C for about 4 hours], and mono-glycidyl ether of C-14 fatty alcohol at a ratio of about 2:2:1 at about 600C temperature in a reactor. The obtained resin mixture was PART A. The formulation is further depicted in Table A below.

Table A: Formulation of breathable coating
Ingredients of Curing Agent (PART B) Wt. % Ingredients of Resin (PART A) Wt.%
5-amino-3-ethyl-1,3-dimethyl cycloheptane ethylamine : 20 wt.% Bisphenol F Dimethacrylate 40 %
BYK 420: Thixotropic agent : 0.5 wt.%
Pre-neutralized fluorocarbon modified polyacrylic : 0.5 wt.% Bisphenol A Dimethacrylate 40%
Organically modified polysiloxane : 0.5 wt.%
Titanium dioxide : 5 wt.% Mono-glycidyl ether of C14 fatty alcohol 20 %
Calcite : 28 wt.%
Silica : 28 wt.%
Barytes
Demineralized water : 4 wt.%
: 13.5 wt. %

PART A and PART B was mixed in 4:5 ratio and was left for about 2 minutes. The composition was then applied by brush over SFC slabs with total thickness of about 200 µm. Curing allowed water evaporation and a film was built within 6-8 hours at room temperature (about 270C). Said coated article/product provided excellent corrosion resistance up to > 2000 hours (Figure 3, Salt spray test), excellent mechanical properties (Table 3), chemical resistance (Table 4) and desirable water vapor permeance of up to 15 g / m2/ 24 hrs (wet cup test). The film properties were also analysed by FT-IR and XRD as depicted in Figure 1, Table 1 and Figure 2, Table 2, respectively.

Table 1: FT-IR of breathable coating composition
Coating Wavenumber (Cm-1) Description
Coating solution 3687.7 -OH
3335/3377.9 -C-OH stretching
2926, 3035,2629 -CH2, -CH3 asymmetric and symmetric structure
2531 CaCO3 (calcite) with Titanium
2075, 1996 Ar-CH overtone
1878 Ar-C-H overtone
1811.4 Ar C-H overtone
1733/1720.5 Ar-C-H overtone
1601/1598.1 C-O stretching (aromatic vibrations)
1504 Carbonate, Ar-C=C-H stretching
1455/1431 -CH2, -CH3 bending
1243/1245 C-C-O-C stretching
1114,1041,1091 SiO32-, -C-N stretching
878,831 Ar-1,4 substitute ring
470, 607.9, 608.8 -C-H, -N-H bending

Table 2: XRD of breathable coating composition
Compound name Structure Reference code Chemical formula
Quartz low Hexagonal 98-008-3849 SiO2
Calcium titanate Orthorhombic 98-009-3082 Ca(TiO3)

Table 3: Mechanical properties of breathable coating composition
Surface/Tem Properties Corrosion Testing Mechanical Testing Drying @ 25°C
DFT 80-100 µ in one time application SST
(ASTM B117) >5000 hours Pull off adhesion test (ASTM D 454) >654 Psi Touch dry
2-3 hours

Scratch resistance (ASTM D5778) 5.0 Kg
Hardness, Shore D (ASTM 2240) 82
Appearance Off white Compressive strength (ASTM D 695) > 18500 Psi Tack free 6-8 hours
Flexural strength (ASTM D 790) > 5800 Psi
Temperature resistance -5 to 800C Tensile strength (ASTM D638) >5500 psi Hard dry 24 hours
Abrasion resistance (ASTM D4060) 55 mg loss /1000 cycles

Table 4: Chemical resistance test of samples for 7-days immersion at 210C (70° F)
Acid/Alkali/solvent/oil Immersion test Acid/alkali/solvent/oil Immersion test
Hydrochloric acid, 33% Occasional contact Bleach 5 % Regular contact
Hydrochloric acid, 10% Occasional contact Sugar (saturated) Regular contact
Sulphuric acid 10 % Short term contact Sodium chloride (5% in water) Regular contact
Sulphuric acid 25 % Short term contact Methanol Regular contact
Sulphuric acid 50 % Avoid contact Butanol Short term contact
Sulphuric acid 98 % Avoid contact Acetone Occasional contact
Phosphoric acid 50 % Short term contact Xylene Short term contact
Acetic acid 5 % Occasional contact Lubrication oil Regular contact
Sodium hydroxide 20 % Regular contact Gasoline Regular contact
Ammonia 10 % Short term contact skydrol Short term contact
Bleach concentrate Short term contact

Chemical resistance test was conducted for seven days with various types of concentrates by varying the concentrations. The coated samples exhibit excellent chemical resistance in regular/continuous immersion for 7 days in various concentrates like lubrication oil, gasoline, 20 % sodium hydroxide, bleach (5%), sugar (saturated), methanol and sodium chloride (5 % in water) for 7 days. In 33 % of hydrochloric acid, 10 % of hydrochloric acid, 5 % of acetic acid and acetone, the coated samples exhibited occasional chemical resistance (6-8 hours of immersion for 7 days) while in some concentrates like 10 % sulphuric acid, 25 % sulphuric acid, 50 % phosphoric acid, 10 % ammonia, skydrol, xylene, butanol and bleach concentrate, the coated samples exhibited short term chemical resistance (2-3 hours of immersion for 7 days). Overall, the present coating composition exhibited good chemical resistance.

Wet cup test (ASTM E 96)
The water was placed in a dish and then the SFC slab coated with the present coating composition (100 mm thick slab) was placed on it. An initial weight was measured and the slab was put in a test chamber. The test chamber was maintained at a constant temperature of about 230C and a relative humidity of about 50 ± 2 %. After 24 hours, weight of the slab was again measured based on which water vapor transmission rate was calculated using:
WVT= (G/t)/A
where,
G: Weight gain
T: time tested
A: area of the test area

The water vapor transmission rate was found to be 15 g / m2/ 24 hours which indicates desirable water vapor permeance.

WE CLAIM:

1. A coating composition comprising a curing agent and a resin, wherein the curing agent comprises cycloalkyl amine or a substituted cycloalkyl amine thereof, and the resin comprises epoxy acrylate, and wherein the curing agent and resin is present at a ratio of about 3:5 to 5.5:5.

2. The coating composition of claim 1, wherein the curing agent is a mixture comprising cycloalkyl amine, thixotropic or anti-settling agent, anti-crater agent, levelling agent, wetting agent, defoamer, opacifier and filler.

3. The coating composition of any of the preceding claims, wherein the cycloalkyl amine or the substituted cycloalkyl amine is cycloheptane amine or a substituted cycloheptane amine; and wherein the substituted cycloheptane amine is selected from a group comprising 5-amino-3-ethyl-1,3-dimethyl cycloheptane ethylamine, 5-amino-1-ethyl-3,3-dimethyl cycloheptane ethylamine, 4-amino-3-ethyl-1,6-dimethyl cycloheptane ethylamine, and combinations thereof.

4. The coating composition of any of the preceding claims, wherein the thixotropic or anti-settling agent is modified solution of urea, organophilic phyllosilicates, or a combination thereof; the anti-crater agent, levelling agent or wetting agent is selected from a group comprising pre-neutralized fluorocarbon modified poly-acrylic; the defoamer is selected from a group comprising organically modified polysiloxane, silicone based agent and combination thereof; the opacifier is selected from a group comprising rutile titanium dioxide, anatase titanium dioxide and combination thereof; and the filler is selected from a group comprising calcite, barytes, silica 300 mesh and combinations thereof.

5. The coating composition of any of the preceding claims, wherein the curing agent comprises cycloalkyl amine or substituted cycloalkyl amine at a concentration ranging from about 15 to 25 wt%, the thixotropic or anti-settling agent at a concentration ranging from about 0.5 to 1.5 wt%, the anti-crater agent, levelling agent or wetting agent at a concentration ranging from about 0.3 to 0.5 wt%, the defoamer at a concentration ranging from about 0.5 to 1.5 wt%, the opacifier at a concentration ranging from about 3 to 15 wt%, and the filler at a concentration ranging from about 30 to 65 wt%.

6. The coating composition of any of the preceding claims, wherein the curing agent comprises cycloheptane amine or substituted cycloheptane amine at a concentration ranging from about 15 to 25 wt%, modified solution of urea at a concentration ranging from about 0.5 to 1.5 wt%, pre-neutralized fluorocarbon modified poly-acrylic at a concentration ranging from about 0.3 to 0.5 wt%, organically modified polysiloxane at a concentration ranging from about 0.5 to 1.5 wt%, titanium dioxide at a concentration ranging from about 3 to 15 wt%, and fillers comprising calcite at a concentration ranging from about 15 to 45 wt%, silica 300 mesh at a concentration ranging from about 15 to 45 wt% and barytes at a concentration ranging from about 3 to 10 wt%.

7. The coating composition of claim 1, wherein the resin is a mixture comprising epoxy acrylate and viscosity reducing agent.

8. The coating composition of any of the preceding claims, wherein the epoxy acrylate is bisphenol dimethacrylate selected from bisphenol A dimethacrylate, bisphenol F dimethacrylate, or a combination thereof, preferably a combination of bisphenol A dimethacrylate and bisphenol F dimethacrylate; and the viscosity reducing agent is mono-glycidyl ether of fatty alcohol, preferably mono-glycidyl ether of C-14 fatty alcohol.

9. The coating composition of any of the preceding claims, wherein the resin comprises the epoxy acrylate at a concentration ranging from about 60 to 80 wt.%, and the viscosity reducing agent at a concentration ranging from about 20 to 40 wt.%.

10. The coating composition of any of the preceding claims, wherein the resin comprises bisphenol A dimethacrylate at a concentration ranging from about 30 to 40 wt%, bisphenol F dimethacrylate at a concentration ranging from about 30 to 40 wt%, and mono-glycidyl ether of fatty alcohol at a concentration ranging from about 20 to 40 wt%.

11. The coating composition of any of the preceding claims, wherein the composition comprises a curing agent mixture and a resin mixture; wherein the curing agent mixture comprises cycloalkyl amine at a concentration ranging from about 15 to 25 wt%, thixotropic or anti-settling agent at a concentration ranging from about 0.5 to 1.5 wt%, anti-crater agent, levelling agent or wetting agent at a concentration ranging from about 0.3 to 0.5 wt%, defoamer at a concentration ranging from about 0.5 to 1.5 wt%, the opacifier at a concentration ranging from about 3 to 15 wt%, and the filler at a concentration ranging from about 30 to 65 wt%, and the resin mixture comprises epoxy acrylate at a concentration ranging from about 60 to 80 wt%, and viscosity reducing agent at a concentration ranging from about 20 to 40 wt%; and wherein said curing agent mixture and the resin mixture is present in the composition at a ratio of about 3:5 to 5.5:5.

12. The coating composition of any of the preceding claims, wherein the composition comprises a curing agent mixture and a resin mixture; wherein the curing agent mixture comprises cycloheptane amine or substituted cycloheptane amine at a concentration ranging from about 15 to 25 wt%, modified solution of urea at a concentration ranging from about 0.5 to 1.5 wt%, pre-neutralized fluorocarbon modified poly-acrylic at a concentration ranging from about 0.3 to 0.5 wt%, organically modified polysiloxane at a concentration ranging from about 0.5 to 1.5 wt%, titanium dioxide at a concentration ranging from about 3 to 15 wt%, and fillers comprising calcite at a concentration ranging from about 15 to 45 wt%, silica 300 mesh at a concentration ranging from about 15 to 45 wt% and barytes at a concentration ranging from about 3 to 10 wt%, and the resin mixture comprises bisphenol A dimethacrylate at a concentration ranging from about 30 to 40 wt%, bisphenol F dimethacrylate at a concentration ranging from about 30 to 40 wt%, and mono-glycidyl ether of C-14 fatty alcohol at a concentration ranging from about 20 to 40 wt%; and wherein said curing agent mixture and the resin mixture is present in the composition at a ratio of about 4:5.

13. A method for preparing the coating composition of any of the preceding claims, comprising:
a) preparing the curing agent and the resin; and
b) mixing the curing agent and the resin at a ratio of about 3:5 to 5.5:5, to obtain the coating composition.

14. The method of claim 13, wherein the curing agent is a mixture comprising cycloalkyl amine or substituted cycloalkyl amine at a concentration ranging from about 15 to 25 wt%, thixotropic or anti-settling agent at a concentration ranging from about 0.5 to 1.5 wt%, anti-crater agent, levelling agent or wetting agent at a concentration ranging from about 0.3 to 0.5 wt%, defoamer at a concentration ranging from about 0.5 to 1.5 wt%, the opacifier at a concentration ranging from about 3 to 15 wt%, and filler at a concentration ranging from about 30 to 65 wt%, and the resin is a mixture comprising epoxy acrylate at a concentration ranging from about 60 to 80 wt%, and viscosity reducing agent at a concentration ranging from about 20 to 40 wt%.

15. The method of claim 13, wherein the curing agent is a mixture comprising cycloheptane amine or substituted cycloheptane amine at a concentration ranging from about 15 to 25 wt%, modified solution of urea at a concentration ranging from about 0.5 to 1.5 wt%, pre-neutralized fluorocarbon modified poly-acrylic at a concentration ranging from about 0.3 to 0.5 wt%, organically modified polysiloxane at a concentration ranging from about 0.5 to 1.5 wt%, titanium dioxide at a concentration ranging from about 3 to 15 wt%, and fillers comprising calcite at a concentration ranging from about 15 to 45 wt%, silica 300 mesh at a concentration ranging from about 15 to 45 wt% and barytes at a concentration ranging from about 3 to 10 wt%, and the resin is a mixture comprising bisphenol A dimethacrylate at a concentration ranging from about 30 to 40 wt%, bisphenol F dimethacrylate at a concentration ranging from about 30 to 40 wt%, and mono-glycidyl ether of C-14 fatty alcohol at a concentration ranging from about 20 to 40 wt%.

16. The method of any of the preceding claims, wherein the curing agent mixture is prepared by adding the cycloalkyl amine or substituted cycloalkyl amine, the thixotropic or anti-settling agent, the anti-crater agent, levelling agent or wetting agent, the defoamer, the opacifier, the filler and water in a homogenizer, and grinding for a time-period of about 45 to 60 minutes.

17. The method of any of the preceding claims, wherein the resin mixture is prepared by blending epoxy acrylate and viscosity reducing agent, preferably bisphenol A dimethacrylate, bisphenol F dimethacrylate and mono glycidyl ether of C-14 fatty alcohol at a ratio of about 2:2:1 in a reactor at a temperature of about 55? to 65? and time-period ranging from about 30 minutes to 45 minutes.

18. The method of any of the preceding claims, wherein the curing agent and the resin are mixed at a ratio of about 4:5, 3:5, 5:5 or 5.5:5, preferably 4:5; and wherein induction period after mixing ranges from about 1 minutes to 2 minutes, preferably 2 minutes.

19. A coated article comprising the coating composition of any of the claims 1-12.

20. The article of claim 19, wherein the article is a steel framed concrete (SFC) coated with the coating composition of any of the claims 1-12.

21. A method of preparing the coated article of claim 19 or claim 20, said method comprising:
a) preparing the coating composition according to the method of any of the claims 13-18; and
b) applying the coating composition on to the article and curing for a time-period of about 6 to 8 hours at a temperature of about 25 ? to 30 ?, to obtain the coated article.