Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See section 10, Rule 13]

A Fire-Resistant Lubricant Composition and Method Thereof

Hindalco Industries Limited, having address at 21st Floor, One Unity Center (Formerly called as One International Center), Tower 4, Prabhadevi, Near Prabhadevi Railway Station, Senapati Bapat Marg, Mumbai – 400013, Maharashtra, India.

The following specification describes the nature of the invention and the manner in which it is to be performed:

FIELD OF INVENTION:

The invention provides a fire-resistant lubricant composition and a method thereof. In particular, the lubricant composition of the present invention is a fire-resistant hydraulic fluid composition for a hydraulic equipment/system.

BACKGROUND OF INVENTION:

Hydraulic equipment/system operating near heat source such as molten metal furnace, open flame system at continuous casting, melting, and holding furnaces, Hot Rolling mills. etc. are prone to fire hazards. Hydraulic lines can be subjected to very high pressures and if a hydraulic line near an ignition source fails, there is a high potential for the system to catch fire and sustain a spray flame, which can result in catastrophic consequences.

The hydraulic fluid is the common element in any hydraulic equipment/system and must be selected very carefully. Quality and cleanliness of the hydraulic fluid are decisive factors for the operational reliability, efficiency, and service life of a system. Hydraulic fluids play several important roles in the smooth operation of a well-balanced and well-designed hydraulic system. These includes heat transfer, power transfer, corrosion prevention, lubrication, prevention of fire hazards.

Whatever the manufacturing facility, a fire is amongst the worst accidents that can take place. The most obvious harm is of injury, or worse, to employees. Beyond that, there is always likely to be a loss in both capital and production. These losses not only include damage to the building and equipment, but also the immediate interruption in production – which might see lines idle for days or even months. Such dangers are inherent within the aluminium production and manufacturing process, given the fundamental requirement for significant heat to produce the desired finished products. Hydraulic lubricants used in industries such as coal mining, iron and steel production, automotive manufacturing, the offshore industry or used on aircraft and ships must have fire resistant properties. In Aluminium Industry FRHF (fire-resistant hydraulic fluid) oil can be used in Hydraulics unit systems for: Continuous casting, melting, and holding furnaces, Rolling mills.

Fortunately, the widespread use of fire-resistant hydraulic fluids has dramatically reduced the risk and limited the damage caused by fires resulting from hydraulic equipment/system failures. Fire resistant hydraulic fluids find their usage in such operating conditions as an alternative to combustible mineral based hydraulic oils for ensuring safe working conditions.

Indian Patent application 202021020984 discloses a lubricant composition comprising (a) 80-99% (W/W) of at least one base oil, (b) 1-10% (W/W) of at least one of a first additive, (c) 0.5 5% (W/W) of at least one of a second additive; and (d) 0.05-0.1% (W/W) of at least one antioxidant. Also provided herein is a method of preparing the lubricant.

WO2020115235A1 discloses a flame-retardant hydraulic oil comprising: a 2,6-di-tert-butylphenol as an additive; and a fatty acid ester containing one or more unsaturated bonds as a base oil.

KR20070087870A discloses an environment-friendly and flame-resistant composition of hydraulic working fluid to improve an environment-friendly effect and to secure good flame resistance, lubricating ability, and thermal and oxidative stability by adding vegetable oil. An environment-friendly and flame-resistant composition of hydraulic working fluid is produced by adding 0.1~20wt.% of an antioxidant, 0.1~15wt.% of a wear resistant additive, and 0.1~15wt.% of a thickening agent to 50~99.9wt.% of one or at least one lubricating base oil selected from a group comprising vegetable oil and synthetic polyol ester. The vegetable oil is one of rape seed oil, canola oil, sunflower oil, castor oil, soybean oil, olive oil, jatropha curcas oil, and palm oil. The synthetic polyol ester is neopentyl glycol ester, trimethylol propane ester, or pentaerythritol ester.

The existing solutions for fire resistant lubricant composition either have higher flash point or has negligible anti-wear resistance. Also, the viscosity index of the existing fire-resistant composition is substantially lower, ultimately leading to comparatively less fire resistance activity. Even though varied fire-resistant lubricant compositions are available, these compositions possess various shortcomings, for example, high cost, energy, complexity, non-environment friendly, fails to improve the quality of the composition, fails to provide increased shelf life to the equipment/system.

In view thereof, there is a need to provide an alternative fire-resistant lubricant composition and the method to manufacture the same, which exhibits superior, fire-resistant properties including higher viscosity, stability, anti-wear resistance and which is environmentally safe and substantially increases the quality and efficiency of the composition along with increasing the shelf life of the hydraulic equipment/system.

OBJECTS OF THE INVENTION:

The aspect of the present invention is to provide a fire-resistant lubricant composition. In an object the present invention provides a method to manufacture said fire-resistant lubricant composition.

Another object of the present invention provides a fire-resistant hydraulic fluid composition with suitable lubricity and higher auto ignition temperature thereby imparting high fire-resistant properties to the lubricant composition.

In an aspect the present invention provides a fire-resistant lubricant composition with substantially higher kinematic viscosity, thereby providing better lubrication over a wider range of temperature. In another aspect, the invention provides a lubricant composition with higher flash point, thereby reducing the hazardous impact and ensuring the safety.

In yet another aspect the present invention provides a fire-resistant lubricant composition that reduces friction & wear resulting in lesser scar diameter, enhancing the anti-wear properties of said composition.

In an aspect the present invention provides a fire-resistant lubricant composition with enhanced shelf life which reduces the maintenance frequency of the hydraulic equipment/system and I turn increases the shelf life of the hydraulic equipment/system.

In an aspect the present invention provides a method to manufacture said fire-resistant lubricant composition.

In an aspect the present invention provides an economical and user-friendly fire-resistant lubricant composition and method thereof which obviates the disadvantages of prior art.
SUMMARY OF THE INVENTION

The present invention relates to a fire-resistant hydraulic fluid lubricant composition for a hydraulic equipment/system. In one embodiment, a fire-resistant lubricant composition comprising at least one base oil, at least one first, second and third additive, at least one defoamer is disclosed.

The base oil in said composition is in the concentration of 95-99.5% by weight. The first additive being an anti-wear additive is in concentration of 0.25-2% by weight, second additive being an extreme pressure additive is in concentration of 0.25-2% by weight and said third additive being an antioxidant is in concentration of 0.01- 0.03 % by weight. Said defoamer is in concentration of 0.01-0.02% by weight.

The fire-resistant lubricant composition is having the flash point ranging from 250 – 350?, with a viscosity index (VI) ranging from 170-200. Said composition is having the anti-wear properties in concentration of 300-600 um, and with a minimum of 315? of auto ignition temperature, imparts the better fire resistance properties.

In another embodiment, a method to manufacture said fire-resistant lubricant composition is disclosed. The method comprises, heating of base oil; preparing mixture of first, second and third additives along with defoamer; mixing of the base oil with said mixture at elevated temperature ranging from 50°C-70°C, preferably for 30 minutes, until forming a consistent composition.

DETAILED DESCRIPTION OF INVENTION:

In describing and claiming the invention, the following terminology will be used in accordance with the definitions set forth below. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. As used herein, each of the following terms has the meaning associated with it in this section. Specific and preferred values listed below for individual process parameters, substituents, and ranges are for illustration only; they do not exclude other defined values or other values falling within the preferred defined ranges.

As used herein, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise.

The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention.

As used herein, the terms “comprising” “including,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to.

The term “lubricant” as used herein refers to substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces.

The term “fire-resistant” as used herein refers to resistance to fire that for a specified time and under conditions of a standard heat intensity, which is to be in the present case determined by the auto ignition temperature.

The present invention is aimed at providing the fire-resistant lubricant composition particularly for the hydraulic equipment/system, and a method of manufacturing thereof. Said lubricant composition is having adequate lubricity and high fire resistance property. Said lubricant preferably finds application in hydraulic system near hot source, like continuous casting, melting, and holding furnaces, hot rolling of aluminium ingot in hot rolling mills & casting operation and automotive manufacturing, coal mining, iron and steel production.

In an embodiment, the present invention relates to a fire-resistant lubricant composition. In an embodiment the composition of the present invention comprises at least one base oil, at least one first additive , at least one second additive, at least one third additive, and at least one defoamer.
In another embodiment, the base oil is preferably a synthetic ester, selected from a groupd comprising fatty acid ester of trimethyl propane such as trimethyl propane trioleate and/or fatty acid ester to pentaerithrol . Said esters enhance the viscosity of the composition and are selected in such a way that the flash point of said ester is greater than 250° C.

The first additive in said composition is an anti-wear additive, soluble in petroleum and synthetic lubricant base stocks and most common solvents, insoluble in water. Said additive is preferably amine salts of aliphatic phosphoric acid. Alternative additive can be amine-neutralized phosphoric acid ester.

The second additive in said composition is an extreme pressure additive. Said additive has polarized hydrocarbons which are attracted to the metal surfaces of the hydraulic equipment/system where they permeate into the metal structure and protect the structure from wear and tear. Said additive is preferably selected from amines, coco alkyldimethyl, N-oxides amongst others.

The third additive in said composition is an antioxidant. Said antioxidant enhances the shelf life of the lubricant thereby requires less frequent lubricant change. Said additive is preferably selected from butylated hydroxyl toluene or butylated hydroxyl anisole, tert-butylhydroquinone amongst others.

The defoamer in said composition hinders the foam formation in the present composition and is preferably selected from group comprising of 3-dimensional siloxanes or a blend of 3-dimensional siloxanes and synthetic hydrocarbon and polysilioxanes.

In yet another embodiment the base oil comprises 95-99.5% by weight. The first additive comprises 0.25-2% by weight, said second additive is in concentration of 0.25-2% by weight and said third additive is in concentration of 0.01- 0.03 % by weight. Said defoamer comprises 0.01-0.02% by weight.

The lubricant composition of the present invention exhibits superior lubricity and fire-resistant properties, along with enhanced wear resistance, stability, and increased shelf life. Said fire-resistant lubricant composition is having the flash point preferably more than 300?, with a viscosity index (VI) ranging from 170-200. Said composition is having the anti-wear properties in concentration of 300-600 um, and with a minimum of 315? of auto ignition temperature, imparting the better fire resistance properties.

In another embodiment the present invention relates to a method to manufacture said lubricant composition, comprising base oil and additives with enhanced lubricity and fire-resistant properties.

In an aspect of this embodiment, the method for manufacturing lubricant composition comprises; heating of said base oil at an elevated temperature of 50-70 ? with a stirring time period of 30 minutes; preparing the mixture of said first, second and third additive along with defoamer at an elevated temperature of 50-70 ? with a stirring time period of 30 minutes; mixing of said base oil into the mixture of additives and defoamer at an elevated temperature of 50-70 ? with a stirring time period of 30 minutes until the consistent lubrication composition is obtained.

EXAMPLES

Examples and implementations are provided herein below for the illustration of the invention. Variations, modifications, and enhancements to the described examples and implementations and other implementations can be made based on what is disclosed. The following examples are provided to illustrate the present invention without limiting it. While the present invention has been described with reference to specific embodiments, this application is intended to encompass those various changes and Substitutions that may be made by those skilled in the art without departing from the scope of the appended claims.

An embodiment of the present invention, illustrates the varied alternatives of the lubricant composition in the disclosed range (C1-C7) as shown in table 1.
TABLE - 1: Present Composition
Sr. No. Components
% w/w Inventive Composition
% w/w
C1 C2 C3 C4 C5 C6 C7
1 Base oil 95- 99.5
TMPTO-68 98.75 98.75 97.75 97.5 95 99.5 98.75
2 First additive (anti-wear additive) 0.25-2
Amine salts of aliphatic phosphoric acid 0.75 0.65 1.5 1.75 2 0.25 1
3 Second additive (extreme pressure additive) 0.25-2
Coco alkyldimethyl, N-oxides 0.5 0.6 1 0.75 2 0.25 0.25
4 Third additive (Antioxidant) – 0.01-0.03
Butylated hydroxyl toluene 0.01 0.01 0.02 0.02 0.01 0.03 0.02
5 Defoamer – 0.01 -0.02
3-d siloxane compound 0.02 0.02 0.02 0.02 0.02 0.02 0.01

In one embodiment, the inventive composition (C1-C7) as disclosed in table 1, were prepared by heating the base oil at an elevated temperature range of 50°C-70°C, preferably for 30 minutes, followed by preparing a mixture of the first, second and third additive along with the defoamer at elevated temperature ranging from 50°C-70°C, preferably for 30 minutes. The obtained mixture was then mixed with base oil at an elevated temperature50°C-70°C, preferably for 30 minutes to obtain the composition (C1-C7).

In another embodiment, the inventive composition as disclosed in table 1 were subjected to various tests such as flash point test, kinematic viscosity test, AW test, coefficient of friction test amongst others to validate the resulting properties of the inventive composition. The same along with the specific test parameters are herein illustrated in Table 2:
TABLE - 2: RESULTING PROPERTIES OF PRESENT INVENTIVE COMPOSITION
Sr. No. Specific tests performed Test Method Inventive Composition
% w/w
C1 C2 C3 C4 C5 C6 C7
1 Flash Point (PMCC), ? IS 1448: (P 21) 314 310 311 312 301 311 315
2 Kinematic Viscosity at 40 ? mm2/s Auto ASTMD445
66.88
66.75
67.98
68.21

69.42

65.8
66.28
3 Kinematic Viscosity at 100 ?, mm2/s Auto ASTMD445 12.44 12.48 12.62 12.75
12.355
12.215 12.28
4 Viscosity Index (VI) IS 1448: (P 56)
188
189
188
190
178
186
186
5 Acidity, mg of KOH/g ASTM D974 1.57 1.52 1.81 1.91
1.82
1.45 1.06
6 AW Test ASTM D4172
435.2
452.1
397.2
410.4
485.1
442.5
375.4
7 Coefficient of Friction Four Ball Tester
2.159
2.152
2.16
2.121
2.138
2.14
2.097
8 EP Test - Pass load, ASTM D2596
160
160
160
120
160
126
160
9 EP Test - Weld load, ASTM D2596
200
200
200
200
200
160
200
10 Copper Corrosion IS 1448: (P 15)
1a
1a
1a
1a
1a
1a
1a
11 Aluminium Corrosion Aluminim sheet sample @ 110 ? for 3 Hours
Normal
Normal
Normal
Normal

Normal

Normal
Normal

In a preferred embodiment, the present lubricant composition C7 comprises 98.75% w/w base oil, 1%w/w first additive, 0.25%w/w second additive, 0.02% w/w third additive and 0.01%w/w of defoamer. In the embodiment, the lubricant composition C7 achieves the improved flash point at 315?, improved viscosity Index at 186 and improved anti wear property at 375.4.

In one embodiment, the constituents of the lubricant composition in their disclosed concentration range, imparts the lubricant composition its enhanced efficiency in terms of achieving higher flash point, increased viscosity index and better wear resistance properties which leads to impart increased fire-resistant properties to the lubricant composition. The same is illustrated herein above by inventive composition C5 and C6, demonstrating the resultant efficiency of lubricant composition, when the constituents of the composition are used beyond the lower and upper limits of the disclosed range. In case if the base oil is used below the limits as disclosed by the present invention, the viscosity will increase but at the same time Flash point will decrease. The decrease in flash point is not a desired property while manufacturing a fire-resistant lubricant composition. Further, if the concentration of the third additive is beyond disclosed range, the anti-wear properties of the composition get adversely affected. Hence using the constituents beyond the disclosed limits shall decrease the efficiency of the lubricant composition.

COMPARATIVE DATA:

In one embodiment, the resultant efficiency of the present lubricant composition (C7) of VG 68 grade is compared with one of the the commercially available composition of VG 68 grade as shown in table 3. Where VG68 indicates the viscosity grade of the lubricant composition. The present composition(C7) prepared using the constituents in the disclosed range shows the synergistic effect of the constituents in achieving substantially increased efficiency, which is reflected by the higher flash point, increased viscosity index and better anti wear resistance of the present composition.
Table 03: COMPARATIVE ANALYSIS
Sr. No. Specific tests performed Test Method/ Standard Commercial Product
(VG68) Present Composition
C7 (VG 68)
1 Flash Point (PMCC), ? IS 1448: (P 21) 281 315
2 Kinematic Viscosity at 40 ?, mm2/s Auto ASTMD445 63.46 66.28
3 Kinematic Viscosity at 100 ?, mm2/s Auto ASTMD445 12.11 12.28
4 Viscosity Index (VI) IS 1448: (P 56) 183 186
5 Acidity, mg of KOH/g of oil ASTMD 974 0.91 1.06
6 AW Test,
ASTM D4172 B Four Ball Tester 514.4 375.4
7 Coefficient of Friction Four Ball Tester 2.114 2.097
8 EP Test - Pass load,
ASTM D2596 Four Ball Tester 160 160
9 EP Test - Weld load,
ASTM D2596 Four Ball Tester 200 200
From the above examples and table 1 to 3 it is clear that the components of the present composition in the claimed range achieves a combined effect demonstrating increased efficiency by achieving higher flash point, reduced friction, better lubricity, better viscosity, and better anti wear resistance.

In one embodiment the fire-resistant characteristics achieved through the inventive composition C7 of the present invention was analysed against a standard benchmarking composition of VG68 grade. The resultant characteristics obtained are described herein below in table 4.
Table 4 Fire-Resistant Characteristics - IS 7895-1975
Sr. No. Specific tests performed Parameters Benchmarking
(VG68) Inventive Composition C7 (VG 68) Results
1 Autogenous Ignition Temperature Test Sample Qty 0.07 ml 447 425 There was no Autogenous Iignition observed up to 431 & 424 ? in VG-68 samples respectively. Samples passes the Autogenous Ignition Test as per IS 7895: 1975.
(Deg C) Sample Qty 0.10 ml 450 431
Sample Qty 0.03 ml 442 431
2 Temperature Pressure Spray Ignition Test Burning cotton waste soaked in kerosene Yes Yes Flame propagation was observed but Flame extinguished within 6 Sec after removing the ignition source.
(Yes/No) (Flame extinguished within 6 Sec.) (Flame extinguished within 6 Sec.)
Sparking Device No No Flame propagation was not observed
Oxy-LPG torch Yes Yes Flame propagation was observed but Flame extinguished within 6 Sec after removing the ignition source.
(Flame extinguished within 6 Sec.) (Flame extinguished within 6 Sec.)
3 Flame Propagation Test Arithmetic mean of 10 distances traveled by the tip of flame 2.4 0.4 Difference in two “means” is less than 10.0 mm.
(mm) Mean distance traveled by the tip of flame 68.6 69.8 Mean distance travelled is less than 100 mm. All the individual distance measurements are less than 130 mm.

Autogenous Ignition Temperature Test : Test samples were taken as 0.07, 0.10 and 0.03 ml respectively for injection into the heated test flask. As per the specification, a fluid -shall be considered fire-resistant, according to the requirements of this test, provided that in no instant of the test procedure the ignition temperature of the test sample is less than 315°C.

Temperature Pressure Spray Ignition Test : A 2.5 lit sample of hydraulic fluid test sample was taken in the pressure vessel. Necessary connections for valves, discharge orifice, pressurized nitrogen cylinder, pressure regulator etc. were made as per specification. The pressure vessel was heated electrically so as to maintain the temperature of fluid between 62.5 °C and 67.5 °C. As per specification, If the test does not result in an ignition of any sample of fluid or if an ignition of a sample does not result in flame propagation for a time interval not exceeding 6 seconds at a distance of 450 mm or more from the nozzle tip to the centre of each igniting device, it shall be considered fire-resistant.

Flame Propagation Test: The flame propagation test was undertaken as per following procedure - Two sets each of 10 Nos. of standard test pieces were mixture of 75 g - Each test piece was placed on the standard base burner, with specified gas pressure, flow rate, flame temperature and flame height was positioned vertically below the point of origin of the test piece. The tip of the burner was kept steel plate. As per specification, if the difference between the means does not exceed 10 mm, the final result, shall be the mean of both results. In the opposite case, a third test consisting of 10 determinations shall be carried out with a new mixture. The same shall not spread beyond the field of action of the burner flame by an arithmetic mean value of the two sets of 10 measurements) of 100mm, 95 percent of the individual measurements being 130 mm or less.

The present invention is therefore directed towards a fire-resistant lubricant composition which achieves superior viscosity index, has anti wear properties and increased shelf life along with achieving the standards of fire resistance with a high flash point.

The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others, skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.
, Claims:We Claim:

1. A fire-resistant lubricant composition and method thereof, wherein the composition comprises at least one base oil in range 95-99.5% w/w, at least one first additive in range 0.25-2% w/w, at least one second additive in range 0.25-2% w/w, at least one third additive in range 0.01- 0.03 % w/w and at least one defoamer in range 0.01-0.02% w/w.

2. The lubricant composition as claimed in claim 1, wherein the base oil is selected from group comprising synthetic ester or fatty acid ester having flash point at least greater than 250?.

3. The lubricant composition as claimed in claim 1 and 2, wherein the base oil is trimethyl propane, and pentaerithol ester.

4. The lubricant composition as claimed in claim 1, wherein the first additive is an anti-wear additive and is selected from a group comprising amine salts of aliphatic phosphoric acid, amine neutralized phosphoric acid ester.

5. The lubricant composition as claimed in claim 1, wherein the second additive is an extreme pressure additive and is selected from a group comprising amines, coco alkyldimethyl, and N-oxides.

6. The lubricant composition as claimed in claim 1, wherein the third additive is an antioxidant and is selected from butylated hydroxyl toluene, butylated hydroxyl anisole, and tert-butylhydroquinone.

7. The lubricant composition as claimed in claim 1, wherein the defoamer is selected from a group comprising blend of siloxanes and synthetic hydrocarbon, and polysilioxane.

8. The lubricant composition as claimed in claims 1 to 7, wherein the flash point of the composition greater than 300?.

9. The lubricant composition as claimed in claims 1 to 8, wherein the viscosity index (VI) of composition ranges from 170-200.

10. The lubricant composition as claimed in claims 1 to 9, wherein the anti-wear properties of composition is in concentration of 300-600 um.

11. The lubricant composition as claimed in claims 1 to 10, wherein the composition has at least 315? of auto ignition temperature.

12. The lubricant composition as claimed in claim 1, wherein the method to manufacture the composition comprises:

a) heating of base oil at elevated temperature ranging from 50°C-70°C, preferably for 30 minutes;
b) preparing a mixture of the first, second and third additive along with the defoamer at elevated temperature ranging from 50°C-70°C, preferably for 30 minutes;
c) mixing of base oil and the mixture of step (b) at elevated temperature ranging from 50°C-70°C, preferably for 30 minutes, and obtaining a consistent composition.

Dated this 28th day of February 2024
Hindalco Industries Limited
By their Agent & Attorney

(Nisha Austin)
of Khaitan & Co
Reg No IN/PA-1390