DESC:FIELD OF THE INVENTION
The present invention relates to a continuous film forming rolling oil composition with enhanced lubrication properties. More particularly, the invention relates to a rolling oil composition with a synergistic combination of sulfur and phosphorous based compounds for enhanced lubricating effect by forming a uniform film providing continuous lubrication.

BACKGROUND OF THE INVENTION
In the rolling process, the thickness of the strip is reduced by the action of stretching from side and loading from the top. The coefficient of friction existing in the zone of contact between the roll and strip has a pronounced effect on the roll separating force required to achieve a given reduction in thickness. The theoretical relationship between these forces and the coefficient of friction is complex and based on many assumptions. However, it is reported that the lower the coefficient of friction, lower the rolling load and greater the reduction in thickness that can be achieved. There is also a minimum level below which friction must not be reduced or the grip required to keep the strip moving through the roll bite will be lost, producing skidding. The rolling oil performs the functions of reducing the coefficient of friction at roll bite and cooling of work roll/ strip to avoid heat marks.

Formulations of rolling oils are quite complex. The performance or non-performance of rolling oil becomes quickly evident during its use in rolling mills. A defect in the rolling oil formulation will unveil in a couple of days if not earlier and will require corrective action. The factors affecting the performance of rolling oils are multi-faceted and require special attentions of the formulator as well as user. Performance of the same oil may vary significantly from one use to other depending upon the application, metallurgy and maintenance practices.

PRIOR ARTS
US 4,390,438 describes a rolling oil formulation which used a dibasic acid along with other ingredients, refined animal fat, minor portions of lubricity additives, anti-oxidants, emulsifiers and other additives to reduce the friction coefficient of the formulation.

CA 1181390 also discloses an improved rolling oil composition by adding saturated dibasic acid to animal fat, lubricity additives, antioxidants, emulsifiers and other additives. The formulation shows decreased coefficient of friction.

RU 2322482 discloses cold rolling of strip steel, mainly in reversing rolling mill with lubricating and cooling emulsion containing water and oil with saponification number no less than 130 mg KOH/g.

JP 2008007544 discloses a composition of rolling oil for ultra-thin steel sheet. The emulsion is claimed to be stable, consisting of (a) 100 pts. wt. of at least one base oil selected from the group consisting of mineral oils, animal and plant oils/fats and synthetic esters, (b) 0.1-5 pts. wt. of a nonionic surfactant having an 8-18 HLB, (c) 0.1-20 pts. wt. of an ethylene oxide addition product of a secondary alcohol, and (d) 0.2-5 pts. wt. of a polymeric nonionic surfactant.

JP 10231494 describes a rolling oil composition comprising a mineral oil and/or a monoester obtained from a 12-22 C aliphatic carboxylic acid and a 1-12 C aliphatic alcohol, 5-70 wt % oil or fat, and 20-90 wt% composite ester which is an ester obtained from a dimer acid and/or a polymer aid of a 16-20 C aliphatic unsaturated higher acid and a polyol and of which the residual carboxylic or hydroxyl groups are esterified with a 12-22 C monohydric alcohol or monobasic fatty acid. The lubricating oil may further contain 0.5-5 wt% phosphorus-based extreme-pressure agent and/or sulfur-based extreme-pressure agent.

Similarly, JP 11124592 discloses a cold rolling lubricant composition consisting of animal and/or vegetable fats, oils, esters, a cationic emulsifier and a nonionic polymer compound.

RU 2124406 describes a rolling oil containing mineral oil, anti-wear additive and emulsifying agent. Anti-wear additive is synthetic fatty acid.

JP 2001294887 describes a cold rolling lubricant emulsion which has an improved lubricating property and an excellent surface property. This cold rolling lubricant comprises one or more oils selected from oils, fats, mineral oils and synthetic esters with water in the presence of a surfactant.

JP 6256789 describes a cold pilger rolling with excellent in cooling and lubricating performance and good in degreasing properties. The oil is obtained by mixing a base oil such as a mineral oil or an animal or a vegetable oil with a lubricating additive such as an extreme-pressure additive, e.g. an alkaline earth metallic sulfonate or a chlorine-based extreme-pressure additive.

JP 5098283 deals with a cold rolling oil composition consisting of a base oil comprising at least one member selected from among animal, vegetable and mineral oils and a synthetic fatty acid ester and having a kinematic viscosity of 60-120 mm2/s at 50 ºC, at least two additives selected from among a sulfonate of an alkaline earth metal, a sulfur-containing extreme-pressure additive and a phosphorus-containing extreme-pressure additive and a surfactant. The mean particle diameter of emulsion is 5-10 µm.

JP 5043888 discloses a cold rolling oil which can provide a steel sheet free from surface defects. The oil comprises at least 60wt.% ester formed from a higher fatty acid component containing 5-60wt.% 12-22 C saturated fatty acids and a polyalcohol component and having a viscosity of 150-350 cSt at 40 ºC and 1-20wt.% organosulfur compounds having a minimum sulfur content of 5% and is capable of forming an emulsion of an average particle diameter of 4-15mum.

As per the JP 60161494, a cold rolling oil is an aqueous emulsion of a base oil (having a viscosity of <=15cst at 50 ºC) comprising (i) a synthetic ester (e.g. methyl stearate) or (ii) a mixture of the component (i) and an animal or vegetable oil (e.g. beef tallow) with a water- soluble chelating agent (e.g. ethylenediaminetetraacetic acid-4Na salt) and/or a water-soluble organic acid having two or more carboxyl groups (e.g. oxalic acid).

JP 10298580 provides an oil composition for metal rolling that has excellent circulation stability of O/W type emulsion and adhesion properties. This composition comprises (a) 60-99.8 wt. % of one or two or more kinds of lubricant components selected from mineral oil, fat and oil and fatty acid ester, (b) 0.1-39.9 wt. % of a copolymer containing a polyoxyalkylene derivative.

JP 8325588 discloses a lubricating oil of emulsion type comprising a base oil, a nonionic surfactant and a specific nitrogen compound. The cold-rolling lubricating oil comprises (A) a base oil comprising an oil and a fat, a mineral oil or a synthetic ester, (B) a nonionic surfactant having a mol.wt. of 2000-15000 and a HLB value of 5-9, and (C) the acid adduct salt of a compound.

GB997634 described a composition for use in cold-rolling sheet metal comprises a water emulsion containing 0.7-6.5% of a lubricant selected from palm oil, cottonseed oil, di-n-butyl sebacate, n-butyl stearate, di-2-ethylhexyl phthalate and dioctyl sebacate, 0.02-0.85% of an emulsifier, and chromate ions affording 0.3-1.6% of chromium, the emulsifier.

US 20110277524 A1 (also published as CN102264882A, DE112009004308T5, WO2010073939A1) describes a lubricating oil for use in hot-rolling oil for aluminum sheet, comprises: (a) a mineral oil having a kinematic viscosity of 80 mm2/second or less at 40° C.; (b) 1 to 14 mass % of a fatty acid having 10 to 22 carbon atoms; (c) 5 to 15 mass % of an oil and fat and/or a synthetic ester; (d) 5 to 10 mass % of a phosphorus-containing extreme-pressure agent; (e) 0.1 to 1 mass % of a polyoxyethylene alkyl amine; and 0.1 to 10 mass % of an organic acid salt of a copolymer composed of a (meth)acrylic acid salt, (meth) acrylamide, and at least one amine monomer, and the mass ratio of the component (c) to the component (d) (component (c)/component(d)) is 1/0.6 to 1/1. The lubricating oil for use in hot-rolling oil for aluminum sheet of the invention provides a high level of rolling lubricity, iron corrosion protection in a hot-rolling step and a rolled aluminum sheet with high sheet surface quality can be obtained.

US 5583100 A (also published as CN1047197C, CN1108298A) describes a water-dispersible oil composition for hot rolling aluminum or aluminum alloys having excellent lubricity and emulsion stability and which minimizes heat deterioration over prolonged periods of time contains the following components (a) to (d): (a) a mineral oil, (b) 3 to 30% by weight of a fatty acid or its monoesters, or oils and fats, (c) 0.5 to 10% by weight of a C4 -C18 alkyl or alkenyl phosphoric (or phosphorous) acid ester, and (d) 0.1 to 10% by weight of a salt between a polymer and an organic acid salt, wherein the polymer has an average molecular weight of 10,000 to 1,000,000 and is a copolymer of a monomer.

CN 102746924 A claims an aluminium hot rolling oil is composed of mineral oil 51-70 weight percent anionic surface active agent 1-15 wt % phosphorus extreme pressure agent 1-8 weight percent of anti-rust agent 1-5 wt % mixed alcohol amine 1-3 percent by weight oleic acid 1-3 weight polyatomic alcohol ester 2-15 weight percent of antifoaming agent 0.1-0.5 percent by weight is composed of hot rolling the total weight of oil.

JP 2000-160181 discloses hot rolling oil for stainless steel which is capable of preventing seizure of a roll even in using to an easily seizable material and producing a stainless steel of high quality by including Ca compound fine particles and a polysulfide compound as lubricant components. This stainless steel contains (A) a calcium compound (preferably calcium carbonate) having 0.1-1.5 µm average particle diameter and (B) a polysulfide compound. Preferably, the component B contains =50 wt% of a compound having at least four S atoms in a molecule. Preferably, the hot rolling oil further contains a base oil containing at least one kind selected from a group of a mineral oil and an ester oil. The hot rolling oil prevents seizure of a rolling material onto the surface of a roll by spraying on the surface of a roll and/or a rolling material and producible a stainless steel having high quality.

The aforementioned prior arts disclose a number of rolling oil compositions having lubrication properties. But none of the prior arts mention other requirements of a rolling oil composition, envisaged by the present invention. Therefore, there arises a need to provide rolling oil composition having better lubrication with consistent lubrication to the rolling mill with the passage of time.

SUMMARY OF THE INVENTION
The present invention provides a rolling oil composition with improved lubrication properties, including a uniform film forming rolling oil which provides a continuous lubrication effect with the passage of time.

The present invention provides a continuous film forming rolling oil composition with enhanced lubrication properties. In an aspect, the present invention provides a rolling oil composition with a synergistic combination of sulfur and phosphorous based compounds for enhanced lubricating effect by forming a uniform film having continuous lubrication without any film breakage.

In another aspect, the present invention provides a continuous film forming rolling oil composition comprising:
a lubricating oil comprising of fatty oil/s or synthetic ester/s or their combinations;
a sulfur containing additive; and
a phosphorous containing additive;
characterized in that the rolling oil composition has:
a saponification value in excess of 100; and
a synergistic ratio between the amount of sulfur and phosphorous in the range of 0.3 to 0.8.

In even another embodiment of the present invention, the above rolling oil composition may or may not further comprise one or more of mineral base oil, synthetic base stock, fatty acid, antioxidant, antifoam additive, emulsifier and viscosity index improver as per requirement of industrial rolling plant.

In another aspect, the present invention provides a process for preparing a continuous film forming rolling oil composition comprising:
a) stirring a lubricating oil with heating to about 40 –50 °C;
b) adding sulfur containing additive and phosphorus containing additive to the product of step (a) under stirring condition for about 15-20 minutes;
c) stirring the combination of step (b) along with other additives, if required for 30-40 minutes, maintaining the temperature of about 40 - 50 °C.

In further another embodiment of the present invention, the process for preparing a continuous film forming rolling oil composition further comprises adding one or more of mineral base oil, synthetic base stock, fatty acid, antioxidant, antifoam additive, emulsifier and viscosity index improver, if required.

In one another embodiment of the present invention, the amount of the lubricating oil ranges from about 55 to 95 wt%.

In still another embodiment of the present invention, amount of the sulfur containing additive ranges from about 0.5 to 25 wt%.

In still another embodiment of the present invention, amount of the phosphorous containing additive ranges from about 1 to 20 wt%.

In yet another embodiment of the present invention, the lubricating oil is selected from the group comprising of fatty oil, synthetic ester and combination thereof.

In another embodiment of the present invention, the fatty oil is selected from vegetable oils/fats, animal oils/fats, and combinations thereof.

In another embodiment of the present invention, the fatty oil is selected from the group comprising of castor oil, palm oil, coconut oil, rapeseed oil, soybean oil, karanjea oil, sunflower oil, linseed oil, jajoba oil, lard oil, tallow and combinations thereof.

In another embodiment of the present invention, the synthetic ester is selected from the group comprising of fatty acid esters, polyol esters, polymeric esters, self-emulsifying esters and combinations thereof.

In another embodiment of the present invention, the sulfur containing additive is selected from the group comprising of sulfurized fatty oil, sulfurized ester, sulfurized terpenes, sulfurized oleic acid, alkyl poly sulphides, aryl polysulphides, sulfurized sperm oil, sulfurized mineral oil, mercaptobenzothiazole, chlornaphta xanthate and combinations thereof.

In another embodiment of the present invention, the phosphorous containing additive is selected from the group comprising of Dilauryl phosphate, didodecyl phosphite, trialkylphosphate such as tri(2-ethylhexyl)phosphate, tricresylphosphate (TCP), zinc dialkyl(or diaryl)dithiophosphates (ZDDP), phospho-sulphurized fatty oils, zinc dialkyl(or diaryl)dithiophosphates (ZDDP), trixylylphosphate (TXP), dilauryl phosphate, triaryl phosphate, mixed amine phosphate, amine salt of aliphatic phosphoric ester and combinations thereof.

BRIEF DESCRIPTION OF DRAWINGS
Fig. 1: Friction coefficient graph with time obtained after conducting friction coefficient test on the rolling oil composition as formulated in S. No. 1 (for continuous) and 2 (discontinuous having peak ) of Table 1.

Fig. 2: Friction coefficient graph with time obtained after conducting friction coefficient test on the rolling oil composition as formulated in S. No. 1, 5 and 9 of Table 1.
S. No. 1, 5 and 9 are the examples of good lubricating rolling oils are with continuous film (without any film breakage i.e., peak formation with time) forming properties.

Fig. 3: Friction coefficient graph with time obtained after conducting friction coefficient test on the rolling oil composition as formulated in S. No. 3 and 4 of Table 1.
S. No. 3 and 4 are the examples of poor lubricating rolling oils with lubricating film breakage i. e, peak formation with time.

DETAILED DESCRIPTION OF THE INVENTION

For the present invention, a developmental program was initiated and a large number of chemical additives were used in the development of rolling oil composition and described in the present invention.

The present invention discloses a continuous film forming rolling oil composition comprising a synergistic combination of sulfur and phosphorous based compounds. In particular, the present invention discloses a novel composition of rolling oil with enhanced lubrication property.

While rolling of metal sheets, formation of a uniform or continuous film of the rolling oil compositions on the metal surfaces is important to get the desired and efficient rolling effect. In addition to the formation of a uniform film of the rolling oil, it is also important that the film does not undergo breakage during the rolling process to achieve the desired and efficient rolling effect.

The coefficient of friction (COF) is a dimensionless scalar value which describes the ratio of the force of friction between two bodies and the force pressing them together. The coefficient of friction depends on the materials used. Coefficients of friction range from near zero to greater than one.

A common way to reduce friction is by using a lubricant, such as oil, mixture of oil and water (emulsion) or grease, which is placed between the two surfaces, often dramatically lessening the coefficient of friction. Lubricated friction is a case of fluid friction where a fluid separates two solid surfaces. Lubrication is the process, or technique employed to reduce friction and wear of one or both surfaces in close proximity, and moving relative to each other, by interposing a substance called lubricant between the surfaces to carry or to help carry the load (pressure generated) during rolling between the opposing surfaces i.e., surface of the roll of the plant and the metal surface to be rolled. In most cases the applied load is carried by pressure generated within the fluid due to the frictional viscous resistance to motion of the lubricating fluid between the surfaces. Adequate lubrication allows smooth continuous operation of equipment, with only mild wear, and without excessive stresses or seizures at roll (instrument used for rolling) during operation.

One of the most convenient methods for measurement and monitoring the lubrication is friction coefficient. Rolling plant is generally running continuously for longer time i.e. months after months. Hence the requirement of the excellent rolling lubricant is not only the reduction/low friction coefficient, but also uniform and continuous lubricating film formation on the rolls of the plant. This phenomenon of good lubrication over time is observed in Examples 1, 5 & 9. The bad lubricant may give same absolute value of friction coefficient as the good lubricant, but it will fail during long duration operation as evident in the Examples 2, 3, 4, 6, 7, & 8. When lubrication breaks down (evident from the film breakage and peak formation of friction coefficient curve), metal or other components (roll and steel specimen) can rub destructively over each other, causing heat, poor surface quality and possibly damage or failure of costly and imported rolls causing loss of production, manpower, electricity etc.

An aspect of the invention discloses a rolling oil composition comprising lubricating oil and a combination of sulfur containing additive and phosphorous containing additive. The above rolling oil may or may not comprise of one or more of mineral base oil, synthetic base stock, fatty acid, antioxidant, antifoam additive and emulsifier as per requirement of industrial rolling plant.

In an embodiment of the present invention, the sulfur containing additive is present in the rolling oil composition in an amount of 0.5 to 25 wt% of the composition and the phosphorous containing additive is present in an amount of 1 to 20 wt% of the composition. In another embodiment of the present invention the ratio between the amount of sulfur and phosphorous is in the range of 0.3 to 0.8, both the values inclusive. In yet another embodiment, the lubricating oil contains fatty oil and/or synthetic ester in an amount of 55 to 95 wt% of the composition, and the rolling oil composition has a saponification value in excess of 100 which is responsible for the synergistic effect of sulfur and phosphorous.

In accordance with the present invention the lubricating oil is selected from the group comprising of fatty oil, synthetic ester and a combination thereof.

Fatty oil is selected from vegetable oils/ fats, animal oils, /fats, and combinations thereof. Fatty oil can be selected from the group comprising castor oil, palm oil, coconut oil, rapeseed oil, soybean oil, karanjea oil, sunflower oil, linseed oil, jojoba oil, lard oil, tallow and combinations thereof.

The synthetic ester is selected from the group comprising of fatty acid esters, polyol esters, polymeric esters, self-emulsifying esters and combinations thereof.

The sulfur containing additive is selected from the group comprising of sulfurized fatty oil, sulfurized ester, sulfurized terpenes, sulfurized oleic acid, alkyl poly sulphides, aryl polysulphides, sulfurized sperm oil, sulfurized mineral oil, mercaptobenzothiazole, chlornaphta xanthate and combinations thereof.

In accordance with the present invention, the phosphorous containing additive is selected from the group comprising of Dilauryl phosphate, didodecyl phosphite, trialkylphosphate such as tri(2-ethylhexyl)phosphate, tricresylphosphate (TCP), zinc dialkyl(or diaryl)dithiophosphates (ZDDP), phospho-sulphurized fatty oils, zinc dialkyl(or diaryl)dithiophosphates (ZDDP), trixylylphosphate (TXP), dilauryl phosphate, triaryl phosphate, mixed amine phosphate, amine salt of aliphatic phosphoric ester and combinations thereof.

Process for the preparation of a uniform film forming rolling oil composition:
The fat and/or ester mixture was heated to 40 - 50 ºC with stirring. The cold rolling oil was prepared by adding the extreme pressure, anti-wear additives, emulsifiers, antioxidant/s, base oil etc. to the above mixture of fat and/or ester one by one under stirring condition. 15-20 minutes stirring was generally maintained to dissolve the additive/additives. The final (after addition of the final additive) rolling oil blend stirred for another 30-40 minutes with heating. Ordinary Remi stirrer used for the stirring and dissolving the additives during blending in the laboratory. Precaution should be taken to avoid excessive heating (> 60 ºC) during blending.

A method of determining the saponification number:
The standard test method for measuring Saponification Number of Petroleum Products is ASTM D94. The saponification number expresses the amount of base that will react with 1 g of sample when heated in a specific manner. More specifically, the number of milligrams of potassium hydroxide required to completely saponify 1 gm of oil. Saponification numbers are also used in setting product specifications for lubricants and additives. It is one of the important parameter for indicating lubricating properties of rolling oils.

Procedure for determining saponification value:
1) Weigh required quantity of rolling oil and transfer into the round bottomed flask.
2) Add 25 ml of 0.5 N alcoholic KOH solution to the round bottomed flask.
3) Add 25 ml of methyl ethyl ketone.
4) Follow the above procedure without taking oil for blank titration.
5) Reflux both round bottomed flasks for 1 hour.
6) After reflux, allow both the round bottomed flasks to cool.
7) Titrate both the samples using 0.5 N HCl with phenolphthalein indicator.
8) The disappearance of pink indicates the end point.

Titration Information
Burette solution: HCl
Flask solution: Alcoholic KOH (with and without oil)
Indicator: Phenolphthalein
End point: Disappearance of pink colour
Calculation:
Saponification Value =
(Titre value of blank in ml – Titre value of sample in ml) x (N) HCl x Equivalent wt of KOH
Weight of the sample

Experimental Methods and Conditions for Measuring Friction Conditions:
Two test specimens e.g. a ball on flat disk with test lubricants in between is installed in the test chamber. The top specimen is oscillated on the bottom flat specimen under a steady load of 300N and a temperature range of 50 to 150 ºC simulating the various temperature zones that the oil is subjected to. Friction force is continually measured by a sensor and the friction coefficient is automatically calculated and recorded during the entire test duration. This test gives an indication of the boundary film forming tendency or lubricity of the lubricating oil under a simulated point contact. All conditions for measuring the frictions are 300N, 50-150 ºC, 50 Hz, 1MM, 1 Hr which is depicted on each of the three graphs in Fig. 1, 2 and 3.

Procedure for determining sulfur and phosphorous
These were measured by highly sophisticated analytical instruments. Sulphur and phosphorous content were determined by WDXRF as per ASTM D 2622 and Inductively Coupled Plasma Atomic Emission Spectrometry (ICPA) as per ASTM D4951, respectively.

Having described the basic aspects of the present invention, the following non-limiting examples illustrate specific embodiments thereof.

Example 1:
1) Add Poly glycol, rapeseed oil and palm oil into glass beaker and commence heating with stirring.
2) When the temperature reaches 45 °C add sulfurized fatty oil and stir for 5 minutes followed by addition of Triaryl Phosphate with further stirring for another 10 minutes.
Stir the whole content for 30 minutes maintaining the temperature at 45 °C. Test the product for friction coefficient as per ASTM D-6425.
According to the above example, the combinations of S. No. 1-4 as tabulated in Table 1 are prepared and tested for S/P ratio, saponification number and coefficient of friction.

Example 2:
1) Add Castor Oil, Karanjea Oil, TMP Trioleate and Gr II base Oil into glass beaker and commence heating with stirring.
2) When the temperature reaches 45 °C add Tertiary alkyl polysulfide and stir for 10 minutes followed by addition of mixed amine phosphate with further stirring for another 10 minutes.
3) Add Polyoxyethyle Sorbitan Triooleate and Glycerol monooleate in the container with stirring for 5-10 minutes.
4) Stir the whole content for another 30 minutes maintaining temperature at 45 °C. Test the product for friction coefficient as per ASTM D-6425.
According to the above example, the combinations of S. No. 5-8 as tabulated in Table 1 are prepared and tested for S/P ratio, saponification number and coefficient of friction.

Example 3:
1) Add Coconut Oil, Palm Oil and Pentaerytio tetraoleate into glass beaker and commence heating with stirring.
2) When the temperature reaches 45 °C, add Sulfurized Olefin and stir for 5 minutes followed by addition of amine salt of aliphatic phosphoric acid esters with further stirring for another 10 minutes.
3) Stir the whole content for another 30 minutes maintaining temperature at 45 °C. Test the product for friction coefficient as per ASTM D-6425.
According to the above example, the combination of serial number 9 as tabulated in Table 1 is prepared and tested for S/P ratio, saponification number and coefficient of friction.

Conclusion and explanations of following Table 1 :
S.No 1. (Pass sample-Good Lubrication): The friction coefficient is around 0.1. The composition is having saponification value 138 (more than 100) and S/P ratio = 0.75 (between 0.3-0.8). Hence uniform lubrication without any film breakage and peak formation in friction graph obtained because it fulfilled both of the main requirements, simultaneous fulfilment of (a) saponification value more than 100 and (b) S/P = 0.3-0.8 which are required for the continuous and uniform film without breakage during operation for longer time ( here it is 1 hr.). Hence, formulation is an example of good lubrication of rolling oil for longer time.
S.No 2. (Failed sample- Bad Lubrication): Same formulation as above with saponification value 138 (matching with our claim range >100) but S/P ratio is =1.05 (but out of the claimed range of S/P=0.3-0.8). Hence although the absolute friction coefficient is 0.1, it fails for giving continuous and uniform lubrication (film breakage i.e. peak formation around 13-14 minutes.). Hence it is a bad example of rolling lubrication.

Therefore, good lubrication over time is observed in S. No. 1, 5, 9 & 10 of Table 1 (following Fig 2). The bad lubricant may give same absolute value of friction coefficient as the good lubricant, but it will fail during long duration operation as evident in the S. No. 2, 3, 4, 6, 7, & 8 of Table 1.

Table 1:
S. No Lubricating Oil (Combination of fatty oil and / synthetic ester in the formulation)
% wt Other Ingredients in the formulation
% wt % Sulfur Compound in formulation
( % Sulfur content in additive) % Phosphorous Compound in formulation ( % Phosphorous content in additive) Sulfur/
Phosphorous in the formulation Saponification Value Remarks
on fiction coefficient
(lubrication property)
1. 70% (50% Rapeseed oil + 20 % palm Oil) 19 % Poly Glycol 4.0 % Sulfurised fatty oil
( above additive contains 10 % sulfur) 7% Triaryl Phosphate
(above additive contains 7.6% phosphorous) 0.40/0.53
=0.75 138 Uniform lubrication without any film breakage (good formulation for lubrication) Because:
S/P= 0.30-0.80 and Saponification value 138 ( >100 ) Both claimed condition fulfilled.
2 70% (50% Rapeseed oil + 20 % palm Oil ) 21 % Poly Glycol 4.0 % Sulfurised fatty Oil
(above additive contains 10 % sulfur) 5.0% Triaryl Phosphate
(above additive contains 7.6 % Phosphorous) 0.40/0.38
=1.05 138 Film breakage (Evidence by peak formation) during lubrication. Saponification value is 138(>100). But S/P = 1.05 (not in the range of our claim 0.3-0.8); S/P ratio is not fulfilled.
3 70% (50% Rapeseed oil + 20 % palm Oil ) 22 % Poly Glycol 1.0% Sulfurised fatty Oil
(above additive contains 10 % sulfur) 7% Triaryl Phosphate
(above additive contains 7.6% phosphorous) 0.10/0.53
=0.19 132 Film breakage
(peak formation) as S/P < 0.30 although saponofication value > 100.
4 35% (25% Rapeseed oil + 10 % palm Oil) 54 % Poly Glycol 4.0 % Sulfurised fatty oil
(above additive contains 10 % sulfur) 7 % Triaryl phosphate
(above additive contains 7.6 % phosphorous) 0.40/0.53
=0.75 73 Film breakage
(peak formation ) as Saponification Value 73 (<100) although S/P value 0.75 (within 0.3-0.8)
5 61 % (15 % Castor Oil + 20 % Karajea Oil + 26 % TMP Trioleate) 26 % Gr II base Oil + 3 %Polyoxyethyle Sorbitan Triooleate +0.6 % Glycerol monooleate 1.0 % Tertiary alkyl polysulfide
(above additive contains 20 % sulfur) 8.4 % Mixed amine phosphate
(above additive contains 4.8 % phosphorous) 0.20/0.40
=0.50 112 Uniform lubrication without any film breakage ( no peak formation)
S/P=0.50(0.30-0.80) and Saponification value 112(>100).

6 61 % (15 % Castor Oil + 20 % Karajea Oil + 26 % TMP Trioleate) 18.5 % Gr II base Oil + 3 %Polyoxyethyle Sorbitan Triooleate +0.6 % Glycerol monooleate 0.9% Tertiary alkyl polysulfide
(above additive contains 20 % sulfur) 16.0 % Mixed amine phosphate
(above additive contains 4.8 % phosphorous) 0.18/0.77
=0.23 112 Film breakage (peak formation).
S/P= 0.23 (<0.30) although saponification value is 112 (>100)
7 61 %(15 % Castor Oil + 20 % Karajea Oil + 26 % TMP Trioleate) 25 % Gr II base Oil + 3 %Polyoxyethyle Sorbitan Triooleate +0.6 % Glycerol monooleate 2.0 % Tertiary alkyl polysulfide
(above additive contains 20 % sulfur) 8.4 % Mixed amine phosphate
(above additive contains 4.8 % phosphorous) 0.40/0.40
=1.00 112 Film breakage (peak formation).
As S/P=1.00 (> 0.80) although saponification value is 112 (> 100).
8 41 %(10 % Castor Oil + 15 % Karajea Oil + 16 % TMP Trioleate) 46 % Gr II base Oil + 3 %Polyoxyethyle Sorbitan Triooleate +0.6 % Glycerol monooleate 1.0 % Tertiary alkyl polysulfide
(above additive contains 20 % sulfur) 8.4 % Mixed amine phosphate
(above additive contains 4.8 % phosphorous) 0.20/0.40
=0.50 77 Film breakage
(Peak formation).
Saponification value low=77 (< 100). Although S/P= 0.5
9 88.7% (30% Coconut Oil+ 23.7 %Palm Oil + 35% Penta erytio tetraoleate) ---- 0.80 Sulfurised Olefin (above additive contains 40 % sulfur)
10.5% Amine salt of aliphatic phosphoric acid esters (above additive contains 8.3 % phosphorous) 0.32/0.87
=0.37 190

Uniform lubrication without any film breakage.
S/P = 0.37 (0.30-0.80) and saponification value = 190 ( > 100)
10 88.7% ( Penta erytio tetraoleate) --- 0.80 Sulfurised Olefin (above additive contains 40 % sulfur)
10.5% Amine salt of aliphatic phosphoric acid esters (above additive contains 8.3 % phosphorous) 0.32/0.87
=0.37 165 Uniform lubrication without any film breakage.
S/P = 0.37 (0.30-0.80) and saponification value = 165 ( > 100)

Advantages:
• Present invention provides a uniform film forming rolling oil composition without breakage of the film with the passage of time.
• Present invention provides a rolling oil composition with enhanced lubrication properties.
• Present invention provides a rolling oil composition which is adequate to allow smooth continuous operation of equipment, without excessive stresses or seizures at roll (instrument used for rolling) during operation.
,CLAIMS:We Claim:
1. A continuous film forming rolling oil composition comprising:
a lubricating oil;
a sulfur containing additive; and
a phosphorous containing additive;
characterized in that the rolling oil composition has:
a saponification value in excess of 100; and
a synergistic ratio between an amount of sulfur and phosphorous in the range of 0.3 to 0.8.

2. The rolling oil composition as claimed in claim 1, wherein the amount of lubricating oil ranges from about 55 to 95 wt%.

3. The rolling oil composition as claimed in claim 1, wherein the amount of sulfur containing additive ranges from about 0.5 to 25 wt%.

4. The rolling oil composition as claimed in claim 1, wherein the amount of phosphorous containing additive ranges from about 1 to 20 wt%.

5. The rolling oil composition as claimed in claim 1, wherein the lubricating oil is selected from the group comprising of fatty oil, synthetic ester and combination thereof.

6. The rolling oil composition as claimed in claim 5, wherein the fatty oil is selected from the group comprising of vegetable oils like castor oil, palm oil, coconut oil, rapeseed oil, soybean oil, karanjea oil, sunflower oil, linseed oil, jajoba oil, and animal fats like lard oil, tallow and combinations thereof.

7. The rolling oil composition as claimed in claim 5, wherein the synthetic ester is selected from the group comprising of fatty acid esters, polyol esters, polymeric esters, self-emulsifying esters like butyl stearate, PEG ester, sorbitan ester, glycerol ester, TMP trioleate, pentaerytritol dioleate & tetraoleate, etc and combinations thereof.

8. The rolling oil composition as claimed in claim 1, wherein the sulfur containing additive is selected from the group comprising of sulfurized fatty oil, sulfurized ester, sulfurized terpenes, sulfurized oleic acid, alkyl poly sulphides, aryl polysulphides, sulfurized sperm oil, sulfurized mineral oil, mercaptobenzothiazole, chlornaphta xanthate and combinations thereof.

9. The rolling oil composition as claimed in claim 1, wherein the phosphorous containing additive is selected from the group comprising of Dilauryl phosphate, didodecyl phosphite, trialkylphosphate such as tri(2-ethylhexyl)phosphate, tricresylphosphate (TCP), zinc dialkyl(or diaryl)dithiophosphates (ZDDP), phospho-sulphurized fatty oils, zinc dialkyl(or diaryl)dithiophosphates (ZDDP), trixylylphosphate (TXP), dilauryl phosphate, triaryl phosphate, mixed amine phosphate, amine salt of aliphatic phosphoric ester and combinations thereof.

10. The rolling oil composition as claimed in claim 1, further comprising one or more of mineral base oil, synthetic base stock, fatty acid, antioxidant, antifoam additive, emulsifier and viscosity index improver.

11. A process for preparing a continuous film forming rolling oil composition comprising:
a) stirring a lubricating oil with heating;
b) adding sulfur containing additive and phosphorus containing additive to the product of step (a) under stirring condition; and
c) stirring the combination of step (b) along with other additives, if required to obtain the rolling oil composition.

12. The process as claimed in claim 11, wherein heating in step (a) is performed to a temperature range of about 40 - 50 °C.

13. The process as claimed in claim 11, wherein stirring in step (b) is performed for about 15-20 minutes.

14. The process as claimed in claim 11, wherein stirring in step (c) is performed along with other additives, if required for 30-40 minutes and maintaining a temperature of about 40 - 50 °C.