DESC:FIELD OF THE INVENTION
[001] The invention relates to lubricant formulation and the process of preparing the same. More particularly, the invention relates to a lubricant formulation for copper continuous casting which provides good lubricity, better anti-wear property and overcomes foaming tendency. It also provides protection against microbial growth.

BACKGROUND OF THE INVENTION
[002] Copper continuous casting and rolling is an important process usually used in the wire and cable industry. Copper, a very malleable metal, is well suited for this operation and by drawing, among other things, thin wires used in electric fields are produced.
[003] The cast-rolling wire process flow includes smelting, casting, rolling, and cleaning. Copper cathodes are melted down at 1,200°C, added to the casting machine via troughs as liquid copper and then cast into an endless bar. During the rolling, the diameter of the wire is progressively reduced, while at the same time, a proportional lengthening is obtained. Due to constant changes to the cross-section, the 900°C bar in the rolling train is transformed into a continuous cast rod with a diameter of approx. 23.5 to 8 mm. Rolling produces a product having a constant cross-section throughout its length. Many shapes and sections are possible to roll by the rolling process. At about 400°C to 500°C, the wire is surface treated, cooled down to approximately 40°C and protected with a wax coating before winding onto coils.
[004] Lubrication during copper continuous casting and rolling is an important factor, and its application can help control the forces and metal flow. Lubrication also extends the life of the mold, reduces temperature, and improves surface finish. During the continuous casting process, lubrication of the mould is vital to avoid sticking the strand to the mold. In addition, lubricant also provides good surface quality, heat reduction & dissipation, and protects machinery.
[005] Many lubricants available in the market are used for copper continuous casting, however unable to completely remove the deposit on the machinery. The inadequate lubricity of the conventionally known lubricants leads to metal sticking to rolls leading to copper staining and wearing scar. Further, conventional lubricants provide poor microbial degradation, poor foam protection and consist of triethylamine (TEA) exposure which leads to copper staining and skin problems.
[006] Owing to the foregoing problems, there is a need for improved lubricant formulations, preferably for continuous casting of copper.

SUMMARY OF THE INVENTION
[007] In one aspect, the present invention relates to a lubricant formulation comprising: 95 to 98% w/w of at least one base oil, 1 to 3% w/w of at least one anti-wear additive and extreme-pressure additive (AW/EP), 0.25 to 1 % w/w of at least one metal passivator, 0.01 to 0.05% w/w of at least one biocide, and 0.01 to 0.05% w/w of at least one defoamer, based on the total weight of the formulation.
[008] In another aspect, the invention is directed to a method of method for preparing the lubricant formulation as claimed in claim 1, comprising the steps of: (a) adding at least one base oil and stirring the same at a predetermined high speed and temperature; (b) adding at least one anti-wear additive and extreme-pressure additive along with at least one metal passivator to the base oil prepared in step (a) and stirring the same at a predetermined high speed and temperature; (c) adding at least one biocide along with at least one defoamer to the mixture prepared in step (b), and stirring the same at a predetermined high speed and room temperature to achieve the lubricant formulation.
[009] In a further aspect, the invention is related to a lubricant formulation for copper continuous casting which provides protection against microbial growth, good lubricity, better anti-wear property and overcomes foaming tendency.

DESCRIPTION OF THE DRAWINGS
[010] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 shows the impact of lubricant formulations on total bacterial count: (a) conventional (SK-40); (b) CWD-21; (c) CWD-46; and (d) CWD-47.
Figure 2 shows the impact of lubricant formulations on yeast and fungal count: conventional (SK-40); (b) CWD-21; (c) CWD-46; and (d) CWD-47.
Figure 3 shows the impact of lubricant formulation on foaming property: (a) conventional (SK-40) lubricant demonstrates slight foaming; (b) CWD-46; and (c) CWD-47.
Figure 4 shows the impact of lubricant formulation on copper staining: (a) triethylamine (TEA); and (b) CWD 42 to CWD 47.

DETAILED DESCRIPTION OF THE INVENTION
[011] Before the compositions and formulations of the present invention are described, it is understood that this invention is not limited to particular compositions and formulations described, since such compositions and formulations may, of course, vary. It is also to be understood that the terminology used herein is not intended to be limited since the scope of the present invention will be limited only by the appended claims.
[012] The terms “comprising”, “comprises” and “comprised of” as used herein are synonymous with “including”, “includes” or “containing”, “contains”, and are inclusive or open-ended and do not exclude additional, non-recited members, elements, or method steps. It will be appreciated that the terms “comprising”, “comprises” and “comprised of” as used herein comprise the terms “consisting of”, “consists” and “consists of”.
[013] Furthermore, the terms “first”, “second”, “third” or “(a)”, “(b)”, “(c)”, “(d)” etc. and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein. In case the terms “first”, “second”, “third” or “(A)”, “(B)” and “(C)” or “(a)”, “(b)”, “(c)”, “(d)”, “i”, “ii” etc. relate to steps of a method or use or assay there is no time or time interval coherence between the steps, that is, the steps may be carried out simultaneously or there may be time intervals of seconds, minutes, hours, days, weeks, months or even years between such steps unless otherwise indicated in the application as set forth herein above or below.
[014] In the following passages, different aspects of the present invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.
[015] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some, but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments, as would be understood by those in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.
[016] Furthermore, the ranges defined throughout the specification include the end values as well, i.e., a range of 1 to 10 implies that both 1 and 10 are included in the range. For the avoidance of doubt, the applicant shall be entitled to any equivalents according to applicable law.
[017] In an aspect, the present invention is directed towards a lubricant formulation comprising the following: at least one base oil, at least one anti-wear additive and extreme-pressure additive (AW/EP), at least one metal passivator, at least one biocide, and at least one defoamer.
[018] In an embodiment the lubricant formulation comprises at least one base oil in the range of 95 to 98 % w/w based on the total weight of the formulation. The base oil aids in dissolving additives, has good solvent power, provides basic lubricity and acts as heat transfer media. The base oil can be selected from methyl esters, polyol esters (preferably TMP esters), poly alkylene glycol, water soluble ethylene oxide/ propylene oxide co-polymers. Preferably the base oil comprises of water soluble monol initiated, ethylene oxide/propylene oxide co-polymers.
[019] In an embodiment the lubricant formulation comprises base oil wherein the base oil preferably is a combination of Breox 50 A 50 (60%) and Breox 50 A 140 (40%).
[020] In an aspect the lubricant formulation comprises base oil wherein the preferable viscosity of base oil in the lubricant formulation in the range of 70-80 mm2/s at 40°C
[021] In an embodiment the lubricant formulation comprises at least one Anti-wear additive in the range of 1 to 3% w/w based on the total weight of the formulation and selected from phosphate esters and amines, fatty acid esters.
[022] In an embodiment the lubricant formulation comprises at least one Extreme pressure additive in the range of 1-3 % w/w based on the total weight of the formulation and selected from phosphate esters and amines, fatty acid esters.
[023] Preferably Anti-wear additive or Extreme pressure additive used is ADDITIN RC 9720.
[024] In an embodiment the lubricant formulation comprises at least one metal passivator in the range of 0.25 to 1 % w/w based on the total weight of the formulation. The metal passivator acts as a corrosion inhibitor that counteracts the catalytic effects of metals on oxidation and corrosion. The metal passivators are preferably selected from dimercapto thiadiazole (DMTD) or its derivative, Chromates, nitrates, tungstate and molybdates.
[025] In an embodiment the lubricant formulation comprises at least one biocide preferably in the range of 0.01 to 0.05% w/w based on the total weight of the formulation. The biocides provide control of the bacterial and microbial growth. The biocides of the lubricant formulation are preferably selected from glycol-based solution of 1,2-benzisothiazolinone (BIT), 5-chloro-2-methyl-4-isothiazolin-3-one (CIT) ,2-methyl-4-isothiazolin-3-one (MIT) and 2-bromo-2-nitropropane-1,3-diol (BNPD).
[026] In an embodiment the lubricant formulation comprises at least one defoamer in the range of 0.01 to 0.05% w/w based on the total weight of the formulation and preferably selected from polysiloxane-based compound, blend of Siloxane and water.
[027] In an embodiment the defoamer comprising the blend of siloxane and water has viscosity in the range of viscosity in range 2,500 to 4,000 cps.
[028] In another aspect the present invention is directed towards a method of preparing lubricant formulation comprising the following steps:
a. adding at least one base oil and stirring the same at a predetermined high speed and temperature,
b. adding at least one anti-wear additive and extreme pressure additive along with at least one metal passivator to the base oil prepared in step (a) and stirring the same at a predetermined high speed and temperature,
c. adding at least one biocide along with at least one defoamer to the mixture prepared in step (b), and stirring the same at a predetermined high speed and room temperature, to achieve the lubricant formulation.
[029] In an embodiment of the method, the predetermined high speed is between the range of 500 – 1500 rpm, preferably the predetermined high speed is 1000 rpm.
[030] In an embodiment of the method, the predetermined temperature is in the range of 50 to 70oC, preferably the predetermined temperature is 60oC.
[031] The lubricant formulation prepared according to the described method provide better lubricant properties in terms of viscosity, wear scar diameter, weight load, foaming tendency and microbial growth etc. were observed.
[032] In yet another aspect, the present invention is directed to the use of the lubricant formulation for copper continuous casting which provides good lubricity, better anti-wear property and poor foaming tendency in addition to better protection against microbial growth.

EXAMPLES
[033] The following experimental examples are illustrative of the invention but not limitative of the scope thereof:
[034] Preparation of Lubricant Formulation: The base oils (Breox 50A 50 (60%) + Breox 50A 140 (40%)) were mixed by stirring at 1000 RPM for 30 minutes at 60oC to obtain a mixture; various additives comprising anti-wear additive / extreme pressure additive (RC 9720) and metal passivators (RC 8213) were added to the mixture followed by stirring at 1000 rpm for 30 minutes at 60oC to obtain a mixture. Further, the additives such as biocide (Nipacide BIT 20) and defoamer (Foamban MS 575) were added into the mixture and stirred at 1000 rpm for 30 minutes at room temperature to obtain lubricant formulation. The composition of the examples is provided in Table 1 as follows:
[035] Table 1
S. No. Base Oil Neutralizer
(TEA) AW/EP Metal Passivator Biocide Defoamer
Comp. Ex. 1
(CWD-29) 93.5 5.0 1.0 0.5 0.05 0.05
Comp. Ex. 2
(CWD-30) 92.0 4.9 2.5 0.5 0.05 0.05
Comp. Ex. 3
(CWD-31) 93.5 5.0 1.0 0.5 0.05 0.05
Comp. Ex. 4
(CWD-38) 91.4 5.0 3.0 0.5 0.05 0.05
Comp. Ex. 5
(CWD-39) 90.9 5.0 3.5 0.5 0.05 0.05
Comp. Ex. 6
(CWD-40) 90.4 5.0 4.0 0.5 0.05 0.05
Comp. Ex. 7
(CWD-41) 89.9 5.0 4.5 0.5 0.05 0.05
Comp. Ex. 8
(CWD-42) 89.4 5.0 5.0 0.5 0.05 0.05
Comp. Ex. 9
(CWD-43) 94.4 2.5 2.5 0.5 0.05 0.05
Comp. Ex. 10
(CWD-44) 94.9 2.0 2.5 0.5 0.05 0.05
Comp. Ex. 11
(CWD-45) 95.9 1.0 2.5 0.5 0.05 0.05
Comp. Ex. 12
(CWD-46) 96.4 0.5 2.5 0.5 0.05 0.05
Inv. Ex. 13
(CWD 47) 96.9 0.0 2.5 0.5 0.05 0.05

[036] Results: The lubricant formulations prepared above were evaluated for copper staining by ASTM D 130 and anti-wear properties by ASTM D4172 B. Results of the evaluation test are represented below in Table 2.
[037] Table 2
S. No. Staining on Copper
(on concentrate) Avg. Wear Scar Diameter Results/Observation
Comp. Ex. 1
(CWD-29) 1a 1115.9 Low Copper staining, High Wear scar diameter
Comp. Ex. 2
(CWD-30) 1b 1050.6 High Copper staining and wear scar diameter
Comp. Ex. 3
(CWD-31) Freshly polished (FP) 983.31 No copper staining, High wear scar diameter
Comp. Ex. 4
(CWD-38) 1b - Copper Staining is present
Comp. Ex. 5
(CWD-39) 2c - Copper Staining is high
Comp. Ex. 6
(CWD-40) 3b - Copper Staining is high
Comp. Ex. 7
(CWD-41) 3b - Copper Staining is high
Comp. Ex. 8
(CWD-42) 3b - Copper Staining is high
Comp. Ex. 9
(CWD-43) 2e 883.33 Copper Staining is high
Comp. Ex. 10
(CWD-44) 2e Copper Staining is high
Comp. Ex. 11
(CWD-45) 1b 628.467 Copper Staining is high
Comp. Ex. 12
(CWD-46) 1a 731.247 Low wear scar diameter and coefficient of friction, but presence of copper staining
Inv. Ex. 13
(CWD 47) Freshly polished (FP) 735.41 No copper staining and low wear scar diameter

[038] As demonstrated above, the lubricant formulation particularly, CWD-47 of the present invention showed both no copper staining and low wear scar diameter. The combination of the components in specified proportions provides a lubricant composition having superior benefits in terms of optimum lubricity and anti-wear property.
[039] Figure 4 shows the impact of lubricant formulations CWD-42 to CWD-47 on copper staining in comparison to triethylamine (TEA) and. It can be seen that CWD-47 formulation having 0% loading showed no corrosion while CWD-46 having 0.5% loading showed copper corrosion of 1a as per ASTM D 130.
[040] Further, lubricant composition (CWD-47) as described in Table 2 was further compared with commercially available lubricant SK-40 (an Emulsion of 2.5% w/w of oil, 0.5% w/w IPA (Isopropyl alcohol) and 97 % w/w water) using various parameters. Lubricant properties in terms of viscosity, wear scar diameter, weight load, foaming tendency and microbial growth etc. were observed. Results of the lubricant properties of the above-mentioned formulations are represented below in Table 3.

[041] Table 3:
Test Parameter SK-40 (Benchmarking) CWD-47
(Inv. Ex. 13)
Oil Appearance Clear Brown Liquid Clear Brown Liquid
Stability (24 hr) Stable Stable
Stability (14 days) Stable Stable
Viscosity at 40 Deg C 76.38 74.54
Viscosity at 100 Deg C 10.61 15.3
Viscosity Index 125 218
Staining on Copper Freshly Polished Freshly Polished
Emulsion Concentration 2.5% Oil+ 0.5% IPA 3%
Appearance Translucent Emulsion Translucent Emulsion
Emulsion Stability (24 hr) Stable Stable
Emulsion Stability (14 days) Stable Stable
Ph 7.5-8.5 7.41
Electric Conductivity (Us) 416 132.3
Avg WSD 761.1 735.41
Coefficient of Friction 0.1065 0.0849
Weld Load (kg) 400kg 500kg
Foaming (Collapse Time) 60 ml (86 sec) No foam
Growth of total bacteria (after 7 days) 107 counts/ mL 107 counts/ mL
Growth of Fungi (after 7 days) Moderate growth No growth
Growth of Yeasts (after 7 days) 106 Yeasts/ mL 102 Yeasts/ mL

[042] Thus, the lubricant formulation CWD-47 of present invention provides better protection against microbial growth, poor low foaming tendency compared to commercially available lubricant (Table 3). Additionally, lubricant formulation (CWD-47) has better anti wear property compared to commercially available lubricant.
[043] The effect of inventive lubricant formulations (CWD-47) and the conventional formulation (SK-40) were also evaluated for microbial growth and the effects on bacteria counts after 7 days have been demonstrated in Figure 1 and the effects on yeast and fungal count after 7 days have been demonstrated in Figure 2. Furthermore, the conventional (SK-40) lubricant and the lubricant formulation (CWD-46 and CWD-47) were evaluated for foaming characteristics (Figure 3). It was found that the conventional (SK-40) lubricants demonstrated slight foaming characteristics which settle in approximately 1 to 2 minutes whereas for the lubricant formulations (CWD-46 and CWD-47) no foaming was observed. Thus, the present invention provides better protection against microbial growth. Further provides low foaming tendency as per ASTM D892 standards and better anti wear property as per ASTM D4172 standards.
[044] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since the modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to the person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.

,CLAIMS:1. A lubricant formulation comprising:
- 95 to 98% w/w of at least one base oil,
- 1 to 3% w/w of at least one anti-wear additive and extreme-pressure additive (AW/EP),
- 0.25 to 1 % w/w of at least one metal passivator,
- 0.01 to 0.05% w/w of at least one biocide, and
- 0.01 to 0.05% w/w of at least one defoamer, based on the total weight of the formulation.

2. The lubricant formulation as claimed in claim 1, wherein the base oil is selected from methyl esters, polyol esters, poly alkylene glycol, water-soluble ethylene oxide/propylene oxide co-polymers, or combination thereof.

3. The lubricant formulation as claimed in claim 1, wherein the base oil comprises a combination of Breox 50 A 50 and Breox 50 A 140.

4. The lubricant formulation as claimed in claim 1, wherein the viscosity of the base oil in the lubricant formulation is in the range of 70 to 80 mm²/s at 40°C.

5. The lubricant formulation as claimed in claim 1, wherein the anti-wear additive and extreme-pressure additive (AW/EP) are selected from phosphate esters, amines, and fatty acid esters or combination thereof.

6. The lubricant formulation as claimed in claim 5, wherein the anti-wear additive and extreme-pressure additive (AW/EP) is ADDITIN RC 9720.

7. The lubricant formulation as claimed in claim 1, wherein the metal passivator is selected from dimercapto thiadiazole (DMTD), chromates, nitrates, tungstate, molybdates or combination thereof.

8. The lubricant formulation as claimed in claim 1, wherein the biocide is selected from glycol-based solution of 1,2-benzisothiazolinone (BIT), 5-chloro-2-methyl-4-isothiazolin-3-one (CIT), 2-methyl-4-isothiazolin-3-one (MIT), and 2-bromo-2-nitropropane-1,3-diol (BNPD) or combination thereof.
9. The lubricant formulation as claimed in claim 1, wherein the defoamer is selected from polysiloxane-based compounds or a blend of siloxane and water.

10. The lubricant formulation as claimed in claim 9, wherein the viscosity of the defoamer is in the range of 2,500-4,000 cps.

11. A method for preparing the lubricant formulation as claimed in claim 1, comprising the steps of:
a. adding at least one base oil and stirring the same at a predetermined high speed and temperature;
b. adding at least one anti-wear additive and extreme-pressure additive along with at least one metal passivator to the base oil prepared in step (a) and stirring the same at a predetermined high speed and temperature;
c. adding at least one biocide along with at least one defoamer to the mixture prepared in step (b), and stirring the same at a predetermined high speed and room temperature to achieve the lubricant formulation.

12. The method as claimed in claim 11, wherein the predetermined high speed is between 500 and 1500 rpm and the predetermined temperature is in the range of 50 to 70°C.