September / October 2014 NLGI Spokesman

NLGI

SPOKESMAN

Serving the Grease Industry Since 1933 – VOL. 78, NO. 4, SEPT/OCT 2014

In this issue . . .

• The 2014 NLGI Award Recipients Presentation • A Little Friendly Competition • Appreciation of Sponsors in Photo Recognition • Highlights from NLGI 81st Annual Meeting

HIGHLIGHTS FROM THE

NLGI 81ST ANNUAL MEETING

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PRESIDENT:

VICE-PRESIDENT:

Bruce M. Urban FMC-Lithium Division 2801 Yorkmont Rd., Ste. 300 Charlotte, NC 28208

David Como Dow Corning Corp.

P.O. Box 0994 Midland, MI 48686

SECRETARY:

TREASURER:

Kim Smallwood Citgo Petroleum Corp.

1293 Eldridge Pkwy.

Houston, TX 77077

Joe Kaperick Afton Chemical Corporation 500 Spring St. Richmond, VA 23218-2158

PAST-PRES./ADVISORY:

EXECUTIVE DIRECTOR:

Chuck Coe Grease Technology Solutions LLC 7010 Bruin Ct. Manassas, VA 20111

Kimberly Bott NLGI Inter­national Headquarters 249 SW Noel, Suite 249 Lee’s Summit, MO 64063

DIRECTORS Richard Burkhalter Covenant Engineering Services 140 Corporate Place Branson, MO 65616

Thomas J. Pane King Industries, Inc. Science Road Norwalk, CT 06852

Curt Ellison Chemtool/Metalcote P.O. Box 538 Crystal Lake, IL 60039-0538

Dennis Parks Texas Refinery Corp.

One Refinery Place Ft. Worth, TX 76101

Dave Facchiano The Lubrizol ­Corpo­ration 29400 L­ akeland Blvd.

Wickliffe, OH 44092

Tom Schroeder Axel Americas, LLC P.O. Box 12337 Kansas City, MO 64116

Gian L. Fagan Chevron Lubricants 100 Chevron Way Room 71-7338 Richmond, CA 94802-0627

Raj Shah Koehler Instrument Co. 1595 Sycamore Ave. Bohemia, NY 11716 Dr. Huafeng “Bill” Shen Bel-Ray Co. P.O. Box 526 Farmingdale, NJ 07727

Paul Grives Exxon Mobil Corporation 3225 Gallows Road Room 7C1906 Fairfax, VA 22037

Terry Smith Lubrication Engineers, Inc. P.O. Box 16447 Wichita, KS 67216

Jim Hunt Tiarco Chemical 1300 Tiarco Drive Dalton, GA 30720

Thomas W. Steib The Elco Corporation 1000 Belt Line Street Cleveland, OH 44109

Tyler Jark Lubricating Specialties Co. 8015 Paramount Blvd.

Pico Rivera, CA 90660

Lisa Tocci Lubes ’n’ Greases 6105 Arlington Blvd., Suite G Falls Church, VA 22044

Dr. Anoop Kumar Royal Manufacturing Co., LP 516 S, 25th West Ave. Tulsa, Oklahoma 74127

Ruiming “Ray” Zhang R.T. Vanderbilt Company, Inc. 30 Winfield St. Norwalk, CT 06855

Wayne Mackwood Chemtura 199 Benson Rd. Middlebury, CT 06749

NLGI

OFFICERS

SPOKESMAN

Serving the Grease Industry Since 1933 – VOL. 78, NO. 4, SEPT/OCT 2014

5 NLGI President’s Podium 7

The 2014 NLGI Award Recipients Presentation

10 A Little Friendly Competition 12 Appreciation of Sponsors in Photo Recognition 14 Highlights from NLGI 81st Annual Meeting 18 D evelopment of Grease focusing on Improved

Energy Efficiency - Masamichi Yamamoto, Junichi Imai, Kyodo Yushi Co., LTD

30 C haracteristics of OSP-based Lithium Complex Grease - Govind Khemchandani, Ph.D., The Dow Chemical Company

Ed Oravec Shell Canada Products 400-4th Avenue S.W. Calgary, Alberta Canada T2L 1Y8

TECHNICAL COMMITTEE CO-CHAIRS:

CHAIR, SESSION PLANNING:

J oe Kaperick Afton Chemical Corporation 500 Spring St. Richmond, VA 23218-2158

Joe Kaperick Afton Chemical Corporation 500 Spring St. Richmond, VA 23218-2158

David Turner Shell Global Solutions (US) Inc. 3333 Hwy. 6 South Houston, TX 77082

ON THE COVER Highlights from the NLGI 81st Annual Meeting

SERVICE INDUSTRY ASSISTANCE COMMITTEE CHAIR: J im Hunt Tiarco Chemical 1300 Tiarco Drive Dalton, GA 30720

EDITORIAL REVIEW COMMITTEE CHAIR: Joe Kaperick Afton Chemical Corporation 500 Spring St. Richmond, VA 23218-2158

Published bi-monthly by NLGI. (ISSN 0027-6782) KIMBERLY BOTT, Editor NLGI International Headquarters 249 SW Noel, Suite 249, Lee’s Summit, MO 64063 USA Phone (816) 524-2500, FAX: (816) 524-2504 Web site: http://www.nlgi.org — E-mail: nlgi@nlgi.org One-year subscriptions: U.S.A. $65.00; Canada $80.00; International $109.00; Airmail $147.00. Claims for missing issues must be made within six months for foreign subscribers and three months for domestic. Periodicals postage paid at Kansas City, MO. The NLGI Spokesman is indexed by INIST for the PASCAL database, plus by Engineering Index and Chemical Abstracts Service. Microfilm copies are available through University Microfilms, Ann Arbor, MI. The NLGI assumes no responsibility for the statements and opinions advanced by contributors to its publications. Views expressed in the editorials are those of the editors and do not n­ ecessarily represent the official position of NLGI. Copyright 2014, NLGI. Postmaster: Send address corrections to the above address.

Every search pays off.

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For advertising information, contact Gloria Steinberg Briskin gloria@LubesnGreases.com 800-474-8654; +1 703-536-7676

PRESIDENT’S PODIUM

President’s Podium Bruce Urban

Certification Mark Review Committee The NLGI certification mark for grease is an indication of quality and approval. Each grease that has this mark on its container has undergone extensive testing to make sure it meets several ASTM testing parameters. When a consumer uses grease that has been packaged and registered with this mark, he/she is assured that the grease is of such a quality to be used successfully in the intended service. At this time, there are more than 265 products, marketed by 76 companies, which have one of these marks.

The NLGI has developed an audit procedure to ensure proper use of the NLGI certification mark. The intended result of this audit is to give further credibility and value to the NLGI certification mark. Over the past five years, every company has had at least one product audited for compliance. This initial audit cycle has been completed for 2013 and is underway for 2014.

Over the last six years, a total of 74 companies that have at least one product registered as GC-LB, GC, or LB have been chosen at random from the entire list of registrants to submit a product to an independent laboratory for testing. The required tests were chosen from the applicable certification requirements the

product is listed under. If a company has more than one product registered, a product was chosen by random.

Within the last 12 months American Refining Group, Inc., BG Products, Inc., Comercial Roshfrans, S.A. de C.V., Environmental Lubricants, Lubri-Lab Inc., Marathon Petroleum, Safety-Kleen Systems, Inc., and Top 1 Oil Products have all submitted samples to an independent laboratory and reported passing results to the NLGI. The NLGI wishes to thank these companies for successfully participating in the audit.

The companies chosen are asked to submit a sample of grease to an independent laboratory and pay for the testing themselves.

As a special consideration for our valued Certification Mark holders, and future holders, NLGI will not be increasing the fees for this service in 2015.

More information is available on the certification mark at the NLGI website, www.nlgi.org Tom Steib, Chair David Como

-5NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

NLGI

INTRODUCING

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GREASE

IN THE UNCOMPROMISING WORLD OF INDUSTRIAL, WHERE METAL MEETS METAL - HIGH LOADS, CORROSION AND CONTAMINATION RARELY RELENT. THAT’S WHERE AFTON’S GREASE MICROBOTZ™ SMOOTH THE WAY. PROTECTING EQUIPMENT, PREVENTING WEAR, AND PROLONGING THE LIFE OF INDISPENSABLE MACHINERY WHERE CONDITIONS ARE AT THEIR HARSHEST. AFTON’S BROAD RANGE OF MULTIFUNCTIONAL GREASE ADDITIVE PACKAGES AND COMPONENTS KEEP GREASE FORMULATION SIMPLE; MAKING COMPLEX, MULTI-INVENTORY MANUFACTURING A THING OF THE PAST, AND GRANTING MAXIMUM FLEXIBILITY FOR PRODUCERS OF SPECIALIZED GREASES. THE GREASE MICROBOTZ™ WORK HARD SO YOU DON’T HAVE TO. CUSHIONING THE GRIND OF HEAVY LOADS. KEEPING WEAR, CORROSION AND CONTAMINATION AT BAY. BEARING DOWN ON BEARING DAMAGE, AND GIVING BOTH GREASE MANUFACTURERS AND CONSUMERS PEACE OF MIND. UNRIVALLED ALLIES. ALWAYS PROTECTING. ALWAYS FIGHTING. ALWAYS THERE.

www.aftonmicrobotz.com

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NUMBER 4 Corporation (NYSE:NEU). © 2013. Afton Chemical Corporation VOLUME is a wholly owned78, subsidiary of NewMarket AFTON®, HiTEC®, MicrobotzTM and Passion for Solutions® are trademarks owned by Afton Chemical Corporation. Passion for Solutions® is a registered trademark in the United States.

THE 2014 NLGI AWARD RECIPIENTS PRESENTATION

Mr. David Como, Dow Corning Corp. receiving the

John A. Bellanti, Sr. Memorial Meritorious Service Award from Mr. Ed Oravec, NLGI Awards Committee Chair.

Mr. Jerry Hopkins, Texas Refinery Corp.-Ret. is also presented with the

John A. Bellanti, Sr. Memorial Meritorious Service Award.

-7NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

NLGI

Receiving the

NLGI Fellow Award

is Mr. Joe Kaperick, Afton Chemical Corp.

The NLGI Author AwardDevelopment

is presented to Mr. Govind Khemchandani, The Dow Chemical Co.,

by Mr. Bill Mallory, Royal Manufacturing (Award Sponsor).

Dr. Naveen Kumar Pokhriyal, Indian Oil Corp. is presented the

Clarence E. Earle Memorial Award

by Mr. Jon Arnson, Rockwood Lithium (Award Sponsor)

-8VOLUME 78, NUMBER 4

NLGI The NLGI Author AwardApplication

went to Mr. Greg Morris, Shell Global Solutions (US).

Presenting is Mr. Gian Fagan, Chevron Global Lubricants (Award Sponsor).

Mr. Roger Miller, Exxon Mobil Corp., received the NLGI Award for

Education Excellence

from Mr. Ed Oravec, Shell Lubricants (Award Sponsor).

Mr. Chuck Coe, Grease Technology Solutions receives an Appreciation Plaque for his final year as the NLGI President.

-9NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

A Little Friendly Competition!

The 30th Annual Fun Run Sponsored by FMC-Lithium Division

Mr. Bruce Urban, FMC-Lithium Division and his wife Annette. Thanks for always putting on such a great event!

2014 Fun Run Winners Men GOLD

Naveen Kumar Pokhriyal, Indian Oil Corp.

SILVER

Vince Vasely, Vanderbilt Chemicals LLC

BRONZE

John Sander, Lubrication Engineers, Inc.

Women GOLD

Andrea Sander, Lubrication Engineers, Inc.

SILVER

Annie Jarquin, Malik PIMS

BRONZE

Jennifer Sanford, FMC-Lithium Division

Winners receive their medals at the Tuesday night dinner.

- 10 VOLUME 78, NUMBER 4

NLGI

Golf Tournament Sponsored by CITGO Petroleum

Mr. Kim Smallwood, CITGO Petroleum, presents the very coveted golf awards!

First Place Low Gross

Second Place Low Gross

Mr. Dave Facchiano

Mr. Kim Smallwood

Mr. John Lorimor

Mr. Don Eggimann

Mr. Alex Kocin

Mr. Al Parrish

Mr. Matt Hardy

Ms. Courtney Scruggs

First Place Low Net Mr. Roger Miller Mr. Delton Rone Mr. Tighe Staed Mr. Chris Decker

Second Place Low Net

Accuracy Drive Men

Mr. Jamie Spagnoli

Mr. John Arnson

Mr. Kevin Tobias Mr. Evan O’Brien Mr. Greg Hutchison - 11 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

APPRECIATION FOR OUR PLATINUM SPONSORS

IN PHOTO RECOGNITION

Monday Continental Breakfast Co-Sponsor Welcoming Reception Co-Sponsor Industry Speaker Co-Sponsor Awards Banquet Decor Co-Sponsor

Refreshments Sponsor

Keynote Speaker Co-Sponsor Saturday Evening Reception Co-Sponsor

Golf Tournament Sponsor

Banquet Entertainment Sponsor - 12 VOLUME 78, NUMBER 4

Photographer Co-Sponsor Awards Banquet Dinner Co-Sponsor Saturday Evening Reception Co-Sponsor

Fun Run Sponsor Welcoming Reception Co-Sponsor Saturday Evening Reception Co-Sponsor

Final Program Guide Sponsor Saturday Evening Reception Co-Sponsor Awards Banquet Dinner Co-Sponsor

Saturday Evening Reception Co-Sponsor Meeting Central Co-Sponsor Golf Breakfast Co-Sponsor

Monday Continental Breakfast Co-Sponsor Saturday Evening Reception Co-Sponsor

Audio Visual Contributor

Saturday Evening Reception Co-Sponsor Welcoming Reception Co-Sponsor Awards Banquet Reception Co-Sponsor Spouse/Guest Program Co-Sponsor General Meeting Co-Sponsor

HIGHLIGHTS FROM THE NLGI 81ST ANNUAL MEETING

- 14 VOLUME 78, NUMBER 4

- 15 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

HIGHLIGHTS FROM THE NLGI 81ST ANNUAL MEETING

- 17 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

Development of Grease

focusing on Improved Energy Efficiency Masamichi Yamamoto Junichi Imai Kyodo Yushi Co., LTD

1. Introduction

In modern times, where energy and resource saving strategies are becoming more important for environmental conservation, the control of air pollutants such as CO2 has been one of the most urgent global issues. Among other CO2 emission sources, plant facilities and automobiles are considered to be the two major contributors. In plant facilities, production machinery and equipment as well as motor-driven fans and pumps consume large amounts of electricity and power plants consequently emit significant amounts of CO2 to cover the electricity demand in the facilities. As for automobiles, there has been a downward trend in the amount of CO2 emissions since the 1990s thanks to the growth of the eco-car. Still, looking at CO2 emission sources by sectors, transportation sector is highly influential against the industrial, residential and energy sectors.

Accordingly, electric and automobile sectors are working on energy- and resource-saving strategies including a reduction of power consumption by improving the torque characteristics of an electric motor.

To be more specific, component and material designs and lubricants are being reviewed for potential torquereducing effects, and grease in its unique “semi-fluid” state has attracted considerable attention being extensively studied to find out application-specific formulations.

This study describes a design concept and study case to develop a rolling element bearing grease with torque reducing effects.

2. Torque generating factor during rolling element bearing operation The torque during rolling element bearing operation occurs accompanied by friction resistance which is classified roughly into three types: grease’s churning resistance, rolling-viscous resistance and seal resistance1).2). Greases are involved especially in the two torque-generating factors: resistance acting on the rolling contact surfaces of rolling elements in elastohydrodynamic lubrication (EHL) and lubricant’s churning resistance observed at any other site (Fig.1).

Considering that these two factors are, basically, dependent on grease base oil viscosity, a low viscosity base oil was conventionally used to decrease bearing torque. However, a low viscosity oil had limited effectiveness as it could only form a thin oil film and shortens the rolling fatigue life of the bearing.

Thus, a new low-torque technique without using a low viscosity base oil, or with using a low viscosity base oil not adversely affecting the rolling fatigue life has been of great interest to bearing manufacturers.

- 18 VOLUME 78, NUMBER 4

NLGI 3. Design concept for low torque 3.1 Low torque by preventing metal-metal contact at low speed

Recently, greases in rolling contact at very low speeds were found to form a much thicker EHL film compared to oil lubrication. Endo et al. conducted an optical interferometric study (Fig.2) on EHL film formed by some typical greases. In their interferometric measurements(Fig.3), a base oil behaved according to the EHL theory in both low- and high-speed ranges.

Whereas, greases approached asymptotically to the base oil at high speed but formed a thick EHL film at low speed. In particular, urea-thickened greases formed a thicker EHL film than lithium-thickened greases, and a horse shoe-shaped interference fringe typically observed in the EHL contact, suggested that the EHL effect was dominating at a low speed, being responsible for the increase in the film thickness 3)4). Their study implied that urea and some greases can form a robust EHL film even at very low speeds in the partial EHL regime and are applicable to a wide range of lubrication regimes. Subsequently, Doe et al. reported their study on an EHL film thickening effect at low speed, based on measurements of isolation voltage and frictional torque between inner and outer rings of deeply grooved ball bearings subjected to axial load (Fig.4). The results of isolation voltage measurements (Fig.5) showed that a base oil maintained stable electrical continuity below 100 rpm, the current flowed less easily at 200 rpm and was almost insulated at 600 rpm. By contrast, grease was not only insulated at high speed but also conducted almost no electricity at 1rpm. These results confirmed the EHL film thickening effect of grease in real rolling element bearings operating at low speeds (Fig.6) and agreed well with the findings of Endo’s study. In their frictional torque measurements (Fig.7), base oils formed an EHL film at high speed and a drop in resistance of the film with decreasing speed, decreased torque. At a lower speed, metal contacts occurred and increased torque. By contrast, greases had a low torque even at low speed, at which base oils had a high torque.

These results demonstrated that frictional torque of the bearing can be considerably decreased even under

severe low speed and high load conditions, where metal contacts leading to high torque are likely to occur in oil lubrication, by the technique of selecting an appropriate thickener that will impart an EHL film thickening effect to a low viscosity oil-based grease5).

3.2 Low torque by reducing churning resistance

Figure 8 shows torque-generating factors for deeply grooved ball bearings operating at 8000rpm. The grease-related resistance makes up more than half of all torque-generating factors, specifically by grease churning resistance and rolling viscous resistance accounting for 45% and 16%, respectively.

Churning resistance of grease in bearings can be reduced by the following two approaches: decreasing viscous resistance, i.e., apparent viscosity of grease with respect to shear rate and optimizing the behavior of grease in bearings. The former can be done, when the same base oil is used, by reducing thickener content (Fig.9). That means, a grease needs to be softened or formulated with a thickener having an exceptional thickening performance. In the torque measurements for two greases of the same base oil viscosity and penetration but a different thickener (Fig.10), grease A having a low thickener, content had a low torque indicating grease churning resistance is significantly affected by the amount of thickener. As for the latter, it should be noted that a grease is usually packed to fill about 20-30% of bearing void and makes a channel which has a large impact on torque level. The behavior of grease in bearings can be divided into two distinct periods as shown in Fig.11: churning period, at which grease is present in all shear area while being churned and channeling period at which a certain portion of grease stays in a fixed position to be involved in lubrication and the other portion is eliminated making a channel.

The impact of churning resistance is more substantial at the churning period than at the channeling period6). A thickener with short fibers is effective in inducing early channeling while long and tangled thickener fibers can stimulate churning (Fig.12). In the torque measurements for two greases of the same base oil viscosity but a different thickener (Fig.13), thickener I had a stable torque within a short time due to early initiation of channeling.

- 19 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

These results confirmed that frictional torque can be decreased by selecting an appropriate thickener to optimize the behavior of grease in bearings instead of using a low viscosity base oil.

3.3 Low torque by reducing rolling viscous resistance

In case of bearings with a contact angle like angular contact ball bearings and tapered roller bearings, toque is greatly affected by traction in grease-lubricated EHL contacts. There have been attempts to reduce traction focusing on “hardware” aspects, for instance by improving bearing internal factors. On the other hand, grease is considered to have much potential for further traction reduction. Under the same operating conditions, contribution of traction differs significantly depending on the molecular structure and formulation of lubricating oil (Fig.14). With lubricating oils of similar formulation and/or structure in the same series, viscosity at normal pressures has minimal impact because traction is associated most closely with a viscosity-pressure coefficient, α7). Therefore, naphthenic mineral oils having “bulky” branched molecular structure with a higher α have a higher traction coefficient than paraffinic mineral oils (Fig.15) 7). Oils with a lower α are effective in reducing traction, meaning that oils with a low traction coefficient such as poly-alpha-olefin can effectively decrease torque.

The results of traction measurements showed that grease I formulated with flat structured poly-alpha-olefin had a lower traction coefficient than a mineral oil-based grease (Fig.16).

4. Study case – Rolling element bearing grease with torque-reducing effect

Table.1 summarizes formulation and general properties of a grease developed for use in automobile bearings. The development objective was an improved torque-reducing effect over the whole speed range. Based on the abovementioned findings, the grease was thickened with urea to prevent an increase in frictional torque at low speed by forming a thick EHL film to avoid metal contact. To ensure low torque at high speed, an urea thickener with exceptional thickening performance was used so as to decrease the solid content and apparent viscosity of the grease. A synthetic hydrocarbon oil was used as a base oil.

In apparent viscosity measurements using a rheometer (Fig.17), the developed grease had approx. 30% less apparent viscosity compared to a conventional grease (Fig.18) indicating that apparent viscosity is highly dependent on solid content in grease. In traction coefficient measurements (Fig.19), the developed poly-Įolefin based grease had a lower traction coefficient than mineral oil-based grease A, being in good agreement with the results with base oil alone as mentioned earlier.

In torque measurements (Fig.20), the developed grease with a low apparent viscosity and a low traction coefficient was proved to have a torque-reducing effect showing about a 50% reduction in running torque in relation to churning resistance and rolling viscous resistance.

5. Summary

This report introduced a study case where a rolling element bearing grease having improved torque-reducing effect was developed without relying on the conventional low viscosity base oil technique. We successfully achieved low torque and long service life at the same time, instead of using a low viscosity base oil which often shortens bearing life, by selecting the best combination of base oil and thickener and identifying the most effective thickener (solid) content to ensure a sufficient EHL film formation and to optimize the grease behavior in bearing.

The developed bearing grease with improved torquereducing effect can be beneficial to the resource- and energy-saving strategies in various industries.

References

1) Tedric A.Harris : Rolling Bearing Analysis Second Edition (1984) 2) Rolling Bearing Engineering, edited by Editorial Committee of Rolling Bearing Engineering, Yokendo (1978) 3) Endo et al. : Tribology Conference Proceedings 5(2008)181.

4) Don et al. : Tribologist, 57,8(2011)62.

5) Don et al. : Tribologist, 56,1(2011)24.

6) Hoshino : Junkatsu : 25 (1980) 547 7) Masayoshi Muraki : Junkatsu,33,11,(1988) 811

- 20 VOLUME 78, NUMBER 4

Fig.1 Grease and torque-generating factors

Fig.2 Ultra thin EHL film thickness measurement system

- 21 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

Fig.3. - EHL film thickness measurement 3),4)

Fig.4 - Bearing torque tester

- 22 VOLUME 78, NUMBER 4

Fig.5 - Electrical potential

Fig.6 - EHL oil film thickness vs speed - rolling element bearing

- 23 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

Fig.7 - Bearing torque vs EHL film thickness

Fig.8 - Torque-generating factor of rolling element bearing (800rpm)

- 24 VOLUME 78, NUMBER 4

Fig.9 - Reduction in churning resistance

Fig.10 - Frictional torque measurement – Grease A, B

- 25 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

Fig.11 - Churning period and channeling period 7)

Fig.12 - Thickener fiber

Fig.13 - Frictional torque measurement – Thickener I and II - 26 VOLUME 78, NUMBER 4

Fig.14 - Traction coefficient 6)

Fig.15 - Traction coefficient 2 6)

Fig.16 - Traction measurement

Properties Thickener Thickener % Base oil Type

Kinematic 40째C viscosity 100째C mm 2/s Worked penetration

Developed grease DiureaA 11 Mineral oil + Synthetic hydrocarbon 69.0 9.19

Conventional Grease DiureaB 22 Mineral oil

280

300

74.7 9.30

Table.1 General formulation and properties

Fig.17 - Rheometer

Fig.18 - Apparent viscosity - developed grease and conventional grease - 28 VOLUME 78, NUMBER 4

Fig.19 - Traction coefficient - developed grease and conventional grease

Fig.20 - Torque - developed grease and conventional grease - 29 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

Characteristics of OSP-based Lithium Complex Grease NLGI Author Award Development

Govind Khemchandani, Ph.D. The Dow Chemical Company

Introduction

Most lubricating greases are made from petroleum oils. However, for some applications, better performance in one or more areas is required, justifying the use of more costly lubricating fluid. Thus, a variety of fluids have become available, each unique but all categorized as synthetic oils. Greases have been made from all of these oils, the thickeners being selected, in most cases, from the ones commonly available. Among the common synthetic oils worth mentioning are polyalkylene glycols (PAGs), organic esters, polyalpha olefins (PAOs) and alkylated aromatics [1].

Most greases consist of three basic parts: a base stock, a thickener and chemical additives. There has been little evolution with two of these parts. A 2011 survey by the U.S. based National Lubricating Grease Institute indicates that more than 90 percent of the grease consumed in the world is formulated with conventional mineral oil base stocks rather than synthetics. The survey also found that more than 75 percent of greases are formulated with lithium soap-based thickeners or lithium complex thickeners, both of which were first patented in the 1940s. Much of the grease in use is based on a 60-yearold concept. Without change in base stocks or thickeners, avenues for performance advances become limited [2].

However, a new class of oil soluble PAGs has recently been introduced in the lube industry [3] [4]. The oil soluble PAGs are based on downstream derivatives of butylene oxide as one of the precursors. The use of higher alkylene oxides, such as butylene oxide, increases the ratio of carbon to oxygen in the PAG, which boosts oil solubility. This innovation is considered a step to change

a “base stock” in a grease formulation. New oil soluble polyalkylene glycols (OSPs) have high viscosity index, better friction properties and excellent solvency power as indicated by very low aniline points. These characteristics make OSPs a good candidate for grease formulations.

An OSP-based lithium complex grease (OSP grease) has been prepared and some of its properties are discussed in this paper.

Objective

Conventional PAGs are used for making greases with inorganic and organic thickeners for specific applications [5]. These conventional PAG based greases fall under the category of “specialty greases” due to conventional PAGs being water soluble and water insoluble types. This restricts PAGs’ use as a base fluid of choice for ³general purpose grease industries applications in the automotive, steel and construction industry. A case in point is PAG fluids for brake caliper applications. Conventional PAG is the fluid of choice for this application since EPDM (ethylene propylene diene monomer) is used in the assembly.

Oil solubility characteristics of OSP fluids give grease makers the option to blend them with mineral oils or synthetic fluids to achieve additional characteristics of lubricity and high temperature deposit elimination which is inherent to PAG chemistry. Oil soluble PAGs thus open the door for making widely used automotive (GC-LB) grease similar to current greases based on mineral oils and PAO. The main focus of the project was to determine if a suitable lithium complex grease can be made meeting GC-LB specifications as outlined in the ASTM D4950 standard [6]. In the components of grease,

- 30 VOLUME 78, NUMBER 4

base oil accounts for about 75-95 percent, meaning that the performance of a grease is largely determined by the characteristics of base oil. Therefore, grease cannot be any better than its base oil [7]. Consequently, before

selecting any base oil, its characteristics should be examined in detail before making a grease for its desired application. Table 1 describes the physical properties of the range of OSP base oils.

Table 1: New Oil Soluble PA Gs-Typical Properties

OSP-18 OSP-32 OSP-46 OSP-68 OSP-150 OSP-220

KV40 cSt ASTM D445 18 32 46 68 150 220

KV100 cSt ASTM D445 4 6.5 8.5 12 23 32

Viscosity Index ASTM D2270 123 146 164 171 186 196

CCS viscosity at -20째C mPa.s ASTM D5293 n/d 1750 2900 5400 17100 29100

OSP-320 OSP-460 OSP-680

320 460 680

36 52 77

163 177 196

n/d n/d n/d

Pour Point, 째C ASTM D97 -41 -57 -57 -53 -37 -34

Flash Point, 째C ASTM D92 204 216 210 218 228 226

Aniline Point, 째C ASTM D611-01 n/d <-30 <-30 <-30 <-30 -22

-37 -35 -30

230 235 243

<-30 <-30 <-30

Important Features of OSPs

Deposit and Varnish Control OSPs are excellent in controlling deposit formation and sludge generation [8]. Every third atom in the polymer is oxygen, imparting polarity and solvating capability. Figure 1 clearly demonstrates the non varnishing characteristics of OSPs and how they contribute high temperature performance compared to mineral oils and synthetic hydrocarbons.

Figure 1: Modified ASTM D 2893B Extended Test, Inclusion of an OSP improves deposit control Mineral Oil, 50 days

Mineral Oil +10% OSP, 70 days

- 31 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

NLGI A recent study by Quantitative Spectrophotometric Analysis (QSA) test method [9] demonstrated reduction in varnish by increasing the solvency power of API Group II base oils. QSA measurements were performed on the used fluid neat, with OSP added at treat levels of 10 and 20 percent. The samples were allowed to sit for 24 hours after the OSP was added. Varnish potential ratings (VPR) for a typical group II using turbine oil containing 20 percent OSP dropped from 90 percent to 10 percent. Even the addition of 10 percent OSP produced a measurable reduction in the VPR of the samples.

Tribological properties

The tribo- profile of OSPs was determined by a MiniTraction Machine (MTM) test and exhibited low traction coefficients across a wide slide to roll ratio range compared to mineral oils [10]. Recently, pressure viscosity coefficients (PVC) data of oil-soluble polyalkylene glycols, high oleic sunflower oil and their 50/50 (wt. %) blends were investigated [11]. The PVC values calculated from the literature data following this procedure showed reasonable agreement with that from film thickness data obtained from this work. This confirms the oil solubility of OSPs even in vegetable oils and film forming ability of OSPs. Optimum film thickness is required for better protection of bearing surfaces.

Solvency Provider

As discussed in many published papers, synthetic fluids like PAOs and other mineral oils have lower solvating power for additives with the exception being naphthenic base oils [12]. Switching from a Group I to Group II base oil has resulted in lower grease yields and additive solubility is now an issue. This has led to the use of naphthenic oils in combination with Group II base oils as solvency providers. Alkylated naphthalene base stocks can also be used to improve additive solubility in PAO [13]. It is obvious from Table 1 that OSPs have very low aniline points and should provide the best solubility for additives, potentially higher yields and a uniform grease structure.

All of the base fluids mentioned above can improve their solvency by using OSPs as a solvency booster component in grease formulation. Such an effect of OSPs in reducing aniline points of naphthenic oil and PAO is shown in Figure 2.

Figure 2: Aniline Point Improvement- Naphthenic Oil (NO) & PAO by OSP 46 - 32 VOLUME 78, NUMBER 4

NLGI OSP L ithium Complex Grease Formulation and Performance Tests

The first step in making an OSP-based lithium complex grease was the selection of OSP- 220 as the base oil.

Its important characteristics are listed in Table 1. 12-Hydroxystearic acid, azelaic acid, and lithium hydroxide monohydrate were reacted in OSP fluid at the required temperatures well known in the art. The base grease was additized with the commercial add-pack containing a combination of typical zinc/sulfur/phosphorous additives. It also contained additional aminic/phenolic antioxidants. This finished NLGI 2 grade with 9 percent soap content was then tested against all the GC-LB requirements. The results are shown in Table 2. The grease was also tested for prolonged working W10K, PDSC, and copper corrosion. The test results are shown in Table 3.

Table 2: Results of GC-L B Testing on Automotive OSP Lithium Complex Grease Property Worked Penetration, mm/10

Method ASTM D 217

NLGI Grade Dropping Point ยบC ASTM Oil Separation, % wt. ASTM Rust Protection, rating, max.

ASTM Water Washout, 80ยบC, % Fretting Wear Protection, weight loss, mg Four Ball Wear, scar diameter, mm Elastomer Compatibility, AMS 3217/3B CR Type, 70 Hrs@100ยบC Volume Change, % Hardness Change (Durometer A Points) Leakage Tendencies, g Low Temp Torque, -40 ยบC Four Ball EP, Weld Load, Kg Load wear Index High Temperature Life, Hours Soap Content: 9.0 % OSP-220: VI 196

Result 275

GC-LB Specs 220-340

2 303 0.91 Pass, No Corrosion

Min. 220 Max. 6 Pass

D 1264 ASTM D 4170

3.2 2.3

Max. 15 Max. 10

ASTM D 2266

0.46

Max.0.60

ASTM D 4289

+5.71 -5

0 to +40 -15 to 0

ASTM D 4290 ASTM D 4693 ASTM D 2596

0.7

Max. 10g

3.21 (See graph)

Max. 15.5 NM

315 60

Min. 200 Kg Min. 30 Kg

ASTM D 3527

80

80

D 2265 D 6184 D 1743

- 33 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

NLGI

Figure 3: Low Temper ature Torque per ASTM D 4693 Shear Stability, , W10k

ASTM D217

4.7

PDSC, 180􀏶C, Minutes

ASTM D 5483

Graph attached

Copper Corrosion

ASTM D 4048

1A

No significant change

Pass

Table 3: Results of Additional Testing on Automotive OSP Lithium Complex Grease

Figure 4: Oxidation Induction T ime per ASTM D 5483

NLGI

Results and Discussions

Currently, the high temperature life of a grease is estimated using the ASTM D 3527 test method. The disadvantage of this method is its poor test precision, long endurance testing time and questionable correlation with field vehicle performance under operating conditions [14]. Subsequently, ASTM D 5483 was developed [15] and became well known for measuring oxidation induction time (OIT) for high temperature stability of greases [16] [17]. In the present investigation, the ASTM D 3527 test was still carried out to comply with GC-LB specifications.

Although PDSC ASTM D 5483 is not a requirement for GC-LB specifications, the author wanted to have this baseline data to indicate oxidation stability of the grease at 180ºC. The test conditions of the method and the OIT curve Figure 3 is displayed per ASTM D 5483. OIT provides an indication of the grease’s thermo oxidative stability and is influenced by several parameters including temperature, grease composition and anti-oxidant additives [18]. Shear stability of the developed grease was measured by worked penetration 10K strokes per ASTM D 217. Test results show that lithium complex grease can be made with OSPs as a base fluid using common manufacturing methods for lithium complex greases.

An appropriate commercial adpack can be used to meet NLGI automotive wheel bearing GC-LB requirements.

Higher drop points greater than 300ºC can be achieved easily with the use of OSP. It has good shear stability, oxidation stability and high drop point with a favorable low soap content of nine percent [19].

Conclusions

It has been shown that it is relatively straightforward to manufacture and formulate an OSP Lithium complex grease for automotive wheel bearings that meets GC-LB performance levels. Formulators can now use oil soluble PAGs as a primary base oil or a co-base oil in grease formulations. OSPs offer options to upgrade hydrocarbon oils to boost solvating power for additives and soaps during grease manufacturing. The introduction of OSPs to the grease market expands the restricted application of conventional PAG based specialty greases to a wide variety of requirements which include general purpose greases and automotive greases.

- 35 NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2014

NLGI 6. References

1. Lubricating Grease Guide , National Lubricating Grease Institute, Mo, pp14-15 2. Tim Sullivan, Averse to Change, Lubes 􀂳N􀂴 Grease, Europe-Middle East-Africa , August 2012, pp 20-24 3. Neil Canter, New Type of Polyalkylene Glycol, Tribology and Lubrication Technology , October 2010, pp10-11 4. Govind Khemchandani, Characteristics of New Oil Soluble Polyalkylene Glycols, STLE Houston Chapter, February 9, 2011 5. US Patent US 2011/0160110 A1, Lubricating Grease Composition, June 30, 2011 6. ASTM D 4950-08, Standard Classification and Specification of Automotive Service Greases, ASTM International, West Conshohockn, PA 7. Luo Robin et al, A Study of Composition and Technology of Complex Lithium Grease , NLGI, October 26-29, 1997 8. Martin Greaves et al, New Oil Soluble Polyalkylene Glycols , STLE, Las Vegas, May 19, 2010 9. Gene Wagenseller, Reducing the Varnish Tendency of a Group II Base Oil by Increasing the Solvency, STLE, May 6-10,2012, St. Louis, Missouri 10. G ovind Khemchandani, 􀂳New Oil Soluble Polyalkylene Glycol for Making High Performance Grease, NLGI , Volume 76, Number 2, pp 36-41 11. G rigor B. Bantchev et al, Film-Forming Properties of Blends of High-Oleic Sunflower Oil with Polyalkyl Glycol, J Am Oil Chem Soc (2012) 89:2227􀂱2235 12. V alentine S, and Luis Bastardo-Zambrano, The changes in the global base oil market and their potential impact on the grease industry, NLGI Spokesman, Vol.74, 2010

13. Sandra Mazzo-Skalski, Synesstic Alkylated Naphthalene Base Stocks for Incidental Food Contact, Tribology and Lubrication Technology , pp.44-46, November 2010 14. In-Sik Rhee, “Developing an Accleerated Endurance Test for Grease - A Status Report”, BRDEC Technical Report , 1987.

15. In-Sik Rhee, ³7KH Development of a New Oxidation Stability Test Method for Greases Using a Pressure Differential Scanning Calorimetry (PDSC),´ NLGI Spokesman, Vol. 55, pp 123-132, 1991.

16. M. J. Pohlen et al, ³DSC-a Valuable Tool for the Grease Laboratory,´ N L G I, October, 1997 17. P. C. Hamblin, S. Laemlin, P. Rohrbac, J. ReyesGavilan and D. Zschech, ³Evaluation of the Thermo Oxidative Characteristics of Greases by Pressurized Differential Scanning Calorimetry,´ Euro Grease, September/October, 2004 18. Jisheng E. et al, ³Comparison Between PDSC and Oxygen Bomb Test Methods for Evaluation of Grease Oxidation Stability,´ Euro G rease, October 2006 19. Richard E. Rush, ³A Review of the More Common Standard Grease Tests in Use Today,´ Journal of the Society of Tribologists and Lubrication Engineers, March 1997, pp18-26

- 36 VOLUME 78, NUMBER 4

Call for Papers – NLGI 82nd Annual Meeting A call is hereby issued for technical papers for presentation at the NLGI 82nd Annual Meeting, which will be held at the Coeur d’Alene Resort, Coeur d’Alene, Idaho, USA from June 6-9, 2015.

Papers approved for presentation at the Annual Meeting may be published in the NLGI Spokesman upon the completion of an NLGI Editorial Review Committee review.

Technical Papers may cover any phase of grease chemistry, grease formulation, or grease manufacturing technology. Of specific interest are papers dealing with product or component toxicology, hazardous material handling or storage as related to the grease industry, and new toxicology, uses, or techniques about any grease subject. Papers are also requested regarding manufacturing of grease products.

If you are interested in submitting a paper for presentation, please send your name, contact information and abstract to: NLGI INTERNATIONAL OFFICE 249 SW Noel St. • Suite 249 Lee’s Summit, MO 64063 USA Phone: 816/524-2500 • Fax: 816/524-2504 Email: marilyn@nlgi.org

NLGI Membership 2015 Membership Dues notices for the calendar year of 2015 will be sent in the coming weeks, electronically as well as by mail. We value the loyal member companies in NLGI and sincerely hope you will remain in the â&#x20AC;&#x153;familyâ&#x20AC;? as we begin another year.

Thanks to our generous members and sponsors, as well as the guidance of the NLGI Board of Directors, the Institute is in excellent financial health. Therefore, NLGI will not be raising Dues again this year!

We hope NLGI continues to be your source for information, education, professional development and networking resources. As always, if you have any suggestions on what would benefit you and your company that NLGI could provide, please let us know. We want your active participation in NLGI!

Enjoy the upcoming holiday season!

- 38 VOLUME 78, NUMBER 4

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Helping the World Run a Little Smoother Lubrizol is helping companies worldwide as a grease additive technology partner. In todayâ&#x20AC;&#x2122;s complex marketplace, you need a company that understands the demands of ever-changing applications, environmental concerns, LEAN manufacturing and worldwide standards and protocols.

Lubrizol is at the forefront of industry advancements offering our customers superior functionality, product consistency, R&D and testing. We are improving grease performance and processes worldwide. To learn more visit www.lubrizol.com.

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