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7.1  Definition of Biobased Lubricants

What is a Biobased Lubricant?

The term Biobased has more than one definition depending on the source. Generally, the definition for Biobased has evolved from collaborative efforts between government agencies and Biobased Industry professionals.

The Farm Security and Rural Investment Act of 2002 (FSRIA) gives the Secretary of Agriculture final authority in defining terms that all stakeholders can agree with. This manual uses the the definition put fourth by Secretary's Memorandum 1042-003, dated January 19, 2005:

 
7.2  Physical Properties of HOBS

High Oleic Base Stocks (HOBS) show performance improvements over petroleum in nearly all categories of lubricant properties.

Test results were conducted in collaboration with Penn State University's Chemical Engineering Department, world renown for its lubricant testing laboratory.

The follow test results confirm these findings.

7.2.1  Introduction to High Oleic Base Stocks (HOBS)

Vegetable oils are mainly consumed in foods.  Vegetable oils also serve as the primary feedstock for the Oleo-Chemical Industry and are gaining popularity with governments, businesses, and consumers for use as high performance lubricating base oils.

Vegetable oils are obtained from renewable resources and are Biodegradable.  Thus, they offer specific environmental benefits over mineral oil-based lubricants.  In addition to environmental benefits, vegetable oils also have certain performance advantages over conventional mineral oil base stocks. These include Low Volatility, high Flash Points, Viscosity Index, and excellent Lubricity.

Historically, the primary drawback of conventional vegetable oils is their lower Oxidation Stability relative to Mineral Oils and certain Synthetic Esters.

Today, with recent advances in Hybrid Breeding technology, it is now possible to alter the physical properties of conventional vegetable oils by changing fatty acid profiles.  One specific example pertaining to vegetable lubricants is the improvement of Oxidation Stability by increasing the Oleic content in various vegetable oils.

Since 1991, Renewable Lubricants, Inc. (RLI) has pioneered an extensive research and development program focused on vegetable oil based lubricants. The primary focus of this program has involved formulating biobased automotive Engine and Hydraulic oils. Recent work in the program has directed R&D toward Food Grade Lubricants, Industrial Fluids, Penetrating Lubricants, Corrosion Inhibitors/Preservative Oils, and Transformer Fluids.  RLI has collaborated with many companies and organizations throughout this R&D program, including Lubrizol, Penn State, USDA, DOD, DOI, DOE, USB, NCGA, and Dow AgroSciences.

RLI has developed patented and proprietary additives demonstrating exceptional performance in High Oleic Base Stocks (HOBS) as lubricant base stocks.  RLI's additive technology, Stabilized, provides a low cost method for stabilizing vegetable base lubricants for high and low temperature Engine, Transmission, Hydraulic, Gear, and Grease applications.

In-house and independent 3rd party test data clearly shows other commercially available compounds have not duplicated the level of performance found in RLI's Biobased Lubricant formulas.

Successful Biobased Lubricant formulas have been developed using HOBS and RLI's Stabilized additive technology.  Extensive government, military, and independent laboratory testing has demonstrated High Oleic Base Stocks (HOBS) have all the required physical properties lubricants must have in order to meet standards already set by industry, world governments, and some of the new GL-4, GL-5 proposed requirements.

HOBS represent a unique opportunity for government and industry to comply with 1999 - 2006 White House Executive Orders in an effort to achieve major objectives for the environment, agriculture, and national security.

7.2.2  Systems Compatibility

Previous research shows, no modification or engineering changes will need to be made in equipment.  Vegetable lubricants are compatible with the same seals and filters as are petroleum lubricants.

In comparing seal swell results of base stocks, vegetable base oils show better seal compatibility than most synthetics.

7.2.3  Extreme Pressure & Anti-Wear Performance

Extreme Pressure and Anti-Wear performance studies were performed at both Penn State and Lubrizol Corporation that ran DIN 51354 FZG Gear Wear Test, ASTM D-4172 Four Ball Wear, and Denison-Vickers Pump Wear tests (See 'Bio Hydraulic Fluid Specification Sheet').

In all of these wear and extreme pressure studies, RLI's technology out performed the reference mineral based oils and formulas.

Penn State University's Chemical Engineering Department, world renown for its lubricant testing laboratory, was chosen for independent wear testing.  This department has developed a large database on the evaluation of transportation lubricants for spark ignition, diesel, and gas turbine engines.  This database includes laboratory test data showing excellent correlation with these engines in lubricant stability and lubricity.

Many papers have been published by SAE, Society of Automotive Engineers, and STLE, Society of Tribologists and Lubricants Engineers (See 'References') on the Four Ball Test and how this test can be run in an appropriate load range that compares well with loads found in Operating Engines, Hydraulic Systems, Transmissions and Gear Boxes. [Refer to References: (1) (2) (3) (4) (5)]

A modified Four-Ball Wear Test using a sequential method to obtain a "run-in" wear and a "steady-state" rate of wear has also been developed for use with Heavy-Duty Hydraulic Systems using a large Caterpillar data base. [Refer to 'References': (6) (7)]

In many cases, such as Bio Transmission Fluids for heavy loaded gearboxes, bio lubricants are required to have Superior Extreme Pressure (EP) properties. The properties can be screened using the Four Ball Wear tester assembly. This test can be supplemented with a scuffing evaluation of lubricants by increasing the load until scuffing occurs. [Refer to References: (8)]

7.2.4  Oxidation Stability

Past research conducted at Penn State and Lubrizol showed RLI's HOBS formulas were as good or better than mineral oils in oxidation stability with less volatility.  The Penn State Micro-Oxidation Test is used to study the high temperature performance of lubricants in the piston top ring area, and shows excellent correlation with the SAE engine sequence III series hot engine test.  See References: (9)(10)(11)(12)(13)  The micro-oxidation test measures deposits, evaporation, and remaining liquid.

When comparing HOBS 10W30 formulas with mineral-based 10W30 SJ and SG engine oils, HOBS formulas perform equal to or better in deposit formation.  The HOBS Sunflower formula shows excellent high temperature stability with only 1.4% deposits.  When comparing deposits, evaporation, and remaining liquid, HOBS 10W30 Motor Oil out performs mineral-based 10W30.  Less evaporation will help reduce emissions and prevent fires.

The Rotary Bomb Oxidation Test (ASTM D 2272) is a rapid method of comparing the oxidation life of lubricants in similar formulations.  It is used to evaluate the oxidation characteristics of Turbine, Hydraulic, Transformer, and Gear Oils.

The test apparatus consists of a pressurized bomb axially rotating at an angle of 30 degrees from the horizontal in a bath at 150 C (302 F).  50 grams of test oil and 5 grams of water are charged to the bomb containing a copper catalyst coil.  The bomb is initially pressurized with oxygen to 90 psi at room temperature.  The 150 C bath temperature causes this pressure to increase to approximately 200 psi.  As oxidation occurs, the pressure drops, and the usual failure point is taken as a 25 psi drop from the maximum pressure attained at 150 C.  The results are reported as the number of minutes to the 25 psi loss.  Longer time means better performance.

In the Rotary Bomb Oxidation Tests conducted at Lubrizol, RLI compared Pennzoil's SJ 10W30 motor oil, and a commercial mineral oil based HF-O Hydraulic Fluid, to RLI's fully formulated HOBS hydraulic fluids.

RBOT test results showed better performance from RLI's HOBS Hydraulic formulas at 260-400 minutes, compared to the mineral oil formulas at 248 - 262 minutes.

7.2.5  High Viscosity - Super Lubricity

Vegetable oils have excellent physical properties.  Vegetable based lubricants are practical and feasible for use in many applications.  Vegetable based oils have substantial benefits over petroleum, or mineral-based oils for use as Lubricant Base Stocks.

Properties include a Super High Viscosity Index (VI) greater than 200 VI for Vegetable Oils (HOBS) versus less than 100 VI for mineral oils.

This high Viscosity Index, combined with an excellent Mechanical Shear Stability, provides the film protection (viscosity) needed to reduce blow-by in the ring and cylinder area.  Reduced blow-by lowers emissions and boosts power and fuel economy.

In addition, these vegetable base oils have a unique fatty acid composition, which produces natural corrosion protection and detergency factors, while providing a long lasting lubricating film to form a protective boundary on metal surfaces.

7.2.6  Low Volatility

According to NOACK (An International Standardized test for Volatility), HOBS have significantly less volatility over solvent refined petroleum (HOBS <1% compared with petroleum >15%).

This means a Stabilized HOBS lubricant will perform at higher temperatures with less evaporation than mineral and synthetic base stocks.

Significantly less volatility reduces oil consumption and emissions.

7.2.7  Low Foam Tendency

According to ASTM D-892 Sequence I, II, III and ASTM D-6082 high temperature foam tests, Stabilized HOBS performed with zero foam and performed better than comparative petroleum and synthetic based stocks.

Less foam means a better lubricating fluid film and steady oil pressure during extensive operation. This property allows HOBS to perform better in high performance, oil pump systems under high volume and/or pressure.

7.2.8  Cold Temperature Stability

The Mini-Rotary Viscometer (MRV) (ASTM D4684) is a low shear rate measurement.  Slow sample cooling rate is the key feature of this instrument.  A sample is preheated to have a specified thermal history, which includes warming, slow cooling and soaking cycles. The MRV measures an apparent yield stress, which is the minimum stress needed to cause oil to flow.  It also measures an apparent viscosity under shear rates of 1 to 50 per second.  This procedure was developed to predict low temperature pumpability of motor and hydraulic oils in field service.

RLI's Cold Temperature Storage Test is used to determine the effects of a fluid under static storage conditions for a determined period. During RLI's R&D program, RLI has found vegetable formulas can pass the standard pour point ASTM D-97 at -35 C, but solidify within 24 hours at higher temperatures (-10 C) in the MRV and Cold Storage Test.  These are some of the problems that have brought dissatisfaction to the use of other past competitive vegetable lubricants by the industry.

The test shows how long a 15 ml formulation can be stored and how it compares with other formulas at -20 C.  This test can also determine the field performance of a hydraulic fluid, gear oil, motor oil, etc., that has been static in the equipment for a period.

An example of a problem area could be in a hydraulic shifting valve that may contain less than 15 ml of fluid that has solidified and prevented the valve from working.  This hydraulic valve could be on equipment that must work in critical areas like in military tactical equipment.  Another problem could be solidified oil in the pump suction or return lines, filters, and any other tight tolerance areas.

After 90 days in this study RLI's Bio Hydraulic Fluid ISO 32 showed excellent performance compared to very poor (failed) performance from other vegetable formulas.

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