Astm stp 1521 2012

ISBN: 978-0-8031-7507-5 Stock #: STP1521 Journal of ASTM International Selected Technical Papers Testing and Use of Environmentally Acceptable Lubricants STP 1521 In-Sik Rhee JAI Guest

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ISBN: 978-0-8031-7507-5

Stock #: STP1521

Journal of ASTM International

Selected Technical Papers

Testing and Use of Environmentally

Acceptable Lubricants

STP 1521

In-Sik Rhee

JAI Guest Editor

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Journal of ASTM International

Selected Technical Papers STP1521

Testing and Use of Environmentally Acceptable Lubricants

JAI Guest Editor:

In-Sik Rhee

ASTM International

100 Barr Harbor Drive

PO Box C700West Conshohocken, PA 19428-2959

Printed in the U.S.A

ASTM Stock #: STP1521

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Library of Congress Cataloging-in-Publication Data

ISBN: 978-0-8031-7507-5

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When citing papers from this publication, the appropriate citation includes the paper authors, “paper title”, J ASTM Intl., volume and number, Paper doi, ASTM International, West Conshohocken, PA, Paper, year listed in the footnote of the paper A citation is provided as a footnote on page one of each paper

Printed in Bay Shore, NYJanuary, 2012

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THIS COMPILATION OF THE JOURNAL OF ASTM INTERNATIONAL

(JAI), STP1521, Testing and Use of Environmentally Acceptable Lubricants,

contains only the papers published in JAI that were presented at a

Symposium on Testing and Use of Environmentally Acceptable Lubricants held during December 6, 2010 in Jacksonville, FL, USA The Symposium was sponsored by ASTM International Committee D02 on Petroleum Products and Lubricants

The Symposium Chairman and STP Guest Editor is Dr In-Sik Rhee, U.S Army TARDEC, Warren, MI, USA

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Overview vii USDA Programs to Support Development and Use of Biobased Industrial Products

C A Bailey 1 Application of ECLs and Today’s Legislation

P Laemmle and P Rohrbach 7 Characteristics of PAG Based Bio-Hydraulic Fluid

G Khemchandani and M R Greaves 17 Polyalkylene Glycols as Next Generation Engine Oils

M Woydt 25 Characteristics of Base Fluid in Environmentally Acceptable Lubricants

B Kusak, G Wright, R Krol, and M Bailey 47 Compatibility of Vegetable Oil Based Lubricating Greases With Different Mineral Oil

Based Greases

A Kumar, S Humphreys, and B Mallory 58 Luminescent Bacteria as an Indicator Species for Lubricant Formulation Ecotoxicity

J Sander, T Smith, and P Bilberry 75

A New Way to Determine the Biodegradability of Lubricants by a Biokinetic Model

I.-S Rhee 83 Thermal Oxidative Stability of Vegetable Oils as Metal Heat Treatment Quenchants

E Carvalho de Souza, G Belinato, R L Simencio Otero, É C Adão Simêncio,

S C M Augustinho, W Capelupi, C Conconi, L C F Canale, and G E Totten 94 Use of Vegetable Oils and Animal Oils as Steel Quenchants: A Historical

Review—1850-2010

R L Simencio-Otero, L C F Canale, and G E Totten 136

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Overview

Environmental safety and compliance has recently become the most icant worldwide issue The generation of the potentially hazardous wastes

signif-by Petroleum not only cause both short and long term liability with respect

to environmental damage, but can result in deteriorated mission ance and high cleanup costs For the last several decades, there has been

perform-an interest in Environmentally Acceptperform-ance (EA) Lubricperform-ants, especially, among agricultural, construction, forestry, lumber, and mining industries where involuntary or accidental fl uid leakage or spillage is detrimental to the environment Another good reason to use EA lubricants is to develop

a market for US grown agricultural feedstocks and to reduce on overseas petroleum crude oil Currently, the biobased based lubricants are consid-ered as EA lubricants due to their environmental properties such as a high biodegradability The biobased lubricant is currently formulated with oils extracted from renewable resources such as plants, crops, trees or animals These types of fl uids are considered less toxic and more biodegradable that conventional petroleum based oils The U.S Department of Agriculture (USDA)’s biobased product guideline also defi nes exactly what products and how much concentration of renewable product associated with fi nal product would be considered as a biobased product In response to the demand of biobased lubricants, many oil companies have formulated bio-based lubricants for the limited applications To explore further develop this technology, researches have already been or are being conducted in the broad science fi eld using biobased oils

ASTM D.2.12 Subcommittee on Environmental Standards of Lubricants has a responsibility to promote the knowledge and the development of stand-ards to measure environmental persistence of lubricants (e.g., biodegradation, ecotoxicity and bioaccumulation) To hold a forum for discussions related to current trends for EA lubricants, the Subcommittee 12 has initiated to have the fi rst Environment Symposium on Testing and Use of Environmentally Acceptable Lubricants which was held on December 6, 2010 at Jacksonville, Florida The purpose of this symposium was to provide details on current re-search efforts to advance use of biobased and other environmentally accept-able lubricants, and to develop new and improved environment test methods Thirteen symposium papers were presented on the various topics related to the fundamentals of biobased lubricants, industrial trends, applications, new test methods, and environmental policies All presentations were very inno-vated and well received from more than 400 attendees Most of papers were published on the Journal of ASTM International after peer reviewed and ten papers among them were selected for presenting in STP These papers are presented here

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Dr In-Sik RheeSymposium Chairman and JAI Guest EditorU.S Army Tank, Automotive ResearchDevelopment and Engineering Center

Warren, Michigan

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Manuscript received November 10, 2010; accepted for publication April 26, 2011; published online July 2011.

1 U.S Department of Agriculture, National Institute of Food and Agriculture, Washington, DC 20250-2210.

Symposium on Testing and Use of Environmentally Acceptable Lubricants on 16 December 2010 in Jacksonville, FL.

Cite as: Bailey, C A., “USDA Programs to Support Development and Use of Biobased Industrial Products,” J ASTM Intl., Vol 8, No 6 doi:10.1520/JAI103565.

J_ID: DOI: Date: 29-November-11 Stage: Page: 1 Total Pages: 6

Copyright V C 2011 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.

1

Reprinted from JAI, Vol 8, No 6 doi:10.1520/JAI103565 Available online at www.astm.org/JAI

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KEYWORDS: biobased products, biobased lubricants, agricultural research

Introduction

Biobased products are broadly defined as nonfood, nonfeed industrial productsderived wholly or significantly in part from renewable plant, animal, marine, orforestry materials Many biobased products are successfully entering the mar-ketplace and adding value to agricultural materials beyond the traditional food,animal feed, and fiber markets This paper is an overview of U.S Department ofAgriculture (USDA) programs to support successful commercialization of bio-based products, from the laboratory to the marketplace

Agriculture is being viewed as a viable solution to alleviating concernsabout unstable oil prices, national security, and the U.S dependence onimported oil The Energy Policy Act of 2007 [1] mandated the Renewable FuelsStandard (RFS2) [2], which sets a target for the production and use of 36 109gal of biofuels by 2022 This goal is significantly impacting the direction ofresearch, development, and commercialization programs in USDA; however,the role of biobased products as replacements for petroleum-based products isbecoming increasingly important as another strategy to reduce the reliance onimported oil

In addition to relieving dependence on imported petroleum, biobased ucts are important for many reasons From a USDA perspective, they create newbusiness opportunities and economic development in rural areas through prod-uct development and new markets, and through diversification of agriculturewith development of new, non-traditional crops that have unique features, e.g.,naturally epoxidized oils From a procurement perspective, biobased productshave advantages such as equal or superior functional performance and environ-mental performance that allows agencies to meet environmental goals by reduc-ing toxic wastes and solid wastes From a national perspective, the United Statescan have a reliable supply of industrial products for defense, industry, and theconsumer, based on renewable raw materials supplied by the American farmer

prod-As more biobased products become commercially viable, USDA’s researchagencies continue to develop new technologies and products through a portfolio

of programs that support research, development of biobased lubricants as well

as other industrial products that can replace petroleum-based products such asplastics, paints, coatings, and adhesives The National Institute of Food andAgriculture (NIFA) [3] is USDA’s principal link to academia and serves as theFederal partner in the land grant university system established in 1862 The suc-cess of American agriculture today is due in large part to the land grant systemthat serves the needs of local communities as well as addressing national goalsthrough research and education Renewable energy and biobased products arepriority topics for NIFA’s academic partners Along with private sector invest-ment, academic research is anticipated to move technologies to commercializa-tion more quickly The Agricultural Research Service is USDA’s [4] in-houseresearch agency with a nationwide network of facilities and research scientiststhat cooperate closely with NIFA and the university system, with many Agricul-tural Research Service (ARS) facilities co-located on university campuses

2 JAI STP 1521 ON ENVIRONMENTALLY ACCEPTABLE LUBRICANTS

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As an agency that supports research and development through extramuralfunding and leadership, NIFA has identified two overarching themes, which areincorporated into many of the agency’s programs that support bioenergy andbiobased products The first theme is sustainability For agriculture, sustainabil-ity is satisfying Americans’ need for food, fiber, feed, and fuel while maintaining

or enhancing environmental quality, rural economic viability, and quality oflife Sustainability is defined in its fullest sense: renewable resources and atten-tion to the environmental, economic, and social impacts of the technologies andproducts as they are developed and commercialized The second overarchingtheme is a systems-based approach that links development of the raw materials,e.g., crop-based oils, the harvest transport and storage of the raw materials, con-version technologies, product development, and markets, i.e., bringing togetherconsortia of experts to address the entire value chain Analytical tools such aslife cycle analysis must be employed to describe the environmental, economic,and social impacts along the value chain and will help to identify research gaps.NIFA expects this approach to biobased product development will result inmore efficient technology transfer and commercialization of the public invest-ment in R&D These themes are reflected in NIFA’s grant programs includingcompetitive funding through the Agriculture and Food Research Initiative Sus-tainable Biofuels Challenge, the Small Business Innovation Research Program,and the Biomass Research and Development Initiative

Examples of Research, Development, and Demonstration of BiobasedLubricants

The University of Northern Iowa National Agriculture-Based Lubricants Center(NABL) [5] has been supported, in part, by USDA programs for over a decade,resulting in a commercial line of industrial lubricants that are used by the truck-ing and rail industries for improved performance over the petroleum-basedcounterparts These products offer advantages that include better adherence tometals, good lubricity and viscosity index Human health and safety advantagesinclude low toxicity and high flash and fire points These products are total losslubricants and so biodegradability in the environment is an important property.Production of biobased lubricants in rural northern Iowa has resulted in newfarming and business opportunities Because biobased lubricants can competesuccessfully with traditional petroleum products, they are catalyzing the emerg-ing biobased industry in the United States

The USDA ARS [6] has developed an efficient process to produce novel based functional fluids based on estolides, which are high molecular weightderivatives of fatty acids The ARS technology has resulted in products withexcellent lubricity, cold temperature, and oxidative stability properties, andthey are biodegradable in the environment A series of estolides has been devel-oped to meet a variety of applications ranging from cosmetics to heavy equip-ment lubrication

bio-USDA collaboration with U.S Army Tank-Automotive Research, ment and Engineering Center Warren, MI, resulted in successful field testing of

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biobased hydraulic fluids [7] in construction equipment at Fort Leonard Wood,

MO Products were tested to MIL-PRF-32073A [8] This specification is cant because it not only defines functional performance requirements but alsoincludes biodegradability in the environment as a performance requirement.USDA BioPreferredSMProgram Creates Market Pull

signifi-New products entering the marketplace encounter numerous obstacles such ashigh prices, invalidated performance to existing industry standards, lack ofstandards, and lack of marketing networks Collaboration among governmentagencies, Academia and the private sector, addressing a systems-basedapproach during the research, development, testing, and evaluation phases ofproducts, can result in successfully overcoming some of these obstacles Creat-ing market pull by establishing purchasing preferences for government agenciescan also address obstacles for new products The Farm Security and RuralInvestment Act of 2002 [9] (2002 Farm Bill) established the Federal Procure-ment of Biobased Products program, renamed BioPreferredSM [10] thatrequires all Federal agencies to give a preference to biobased products over theirnon-biobased counterparts when making purchasing decisions

The BioPreferredSM[10] program consists of two key elements The first ment is related to the above mentioned Federal procurement preference Underthis part of the program, USDA designates categories of commercially availableproducts based on percentage of biobased content Before a category is desig-nated, USDA solicits public comment on minimum percentages for various cat-egories of products (items) that would allow the products to meet performancestandards with maximum feasible biobased content A BioPreferredSM[10] des-ignated item is one that meets or exceeds USDA-established minimum biobasedcontent requirements

ele-Under the BioPreferredSM [10] Program, Federal agencies and their tractors are required to buy products with the highest biobased content Thisapplies to cumulative purchases of at least $10,000 as long as the selected bio-based product is readily available, meets established performance standards,and is reasonably priced Any manufacturer or vendor can apply under the pro-gram to have their products designated as eligible if their products contain therequired biobased levels established by USDA for a designated item USDA alsorequires documentation for manufacturers’ claims about the environmentaland human health effects, life cycle costs, sustainability benefits, and perform-ance of their products State governments across the country have passed legis-lation that complements the federal BioPreferredSM [10] program Ohio,Arkansas, Illinois, Indiana, Iowa, North Dakota, and South Dakota have estab-lished various levels of preference for purchasing biobased products

con-Products that have been designated as biobased are posted on the PreferredSM[10] website that federal agencies and others can use as a referencewhen making purchasing decisions Over 5100 products are eligible forpreferred procurement under the 6 categories that have been designated todate Examples of functional fluids that have been designated are listed inTable 1

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The second key element of the Biopreferred Program is a voluntary labelingprogram established in the Food, Conservation, and Energy Act of 2008 [9] (2008Farm Bill) The USDA Certified Biobased Product label can be used by manufac-turers and vendors as a marketing tool and is anticipated to promote the sale ofbiobased products The labeling program, unveiled January 20, 2011, is intended

to encourage the purchase and use of biobased products by reaching beyond theFederal purchasing community to commercial entities and the general public Inorder to obtain the label, a manufacturer or vendor must have biobased contentvalidated by a certified laboratory using ASTM Method D6866 USDA has set a 25percent minimum biobased content as the entry level for the label

ASTM D6866 [12] uses radiocarbon analysis and was first published in 2004

as an analytical method to determine if a product meets minimum biobasedcontent The standard distinguishes between carbon content in biomass-basedproducts from carbon content in fossil-based products Because biomass con-tains a known amount of C-14, carbon from biomass can be differentiated fromproducts that do not contain C-14 Biobased content is expressed as a percent-age of the total organic carbon content Inorganic carbon, non-carbon materialsand product weight are not taken into consideration for calculating percent bio-based content The standard does not measure product biodegradability, and so

TABLE 1—Examples of Functional Fluids that have been designated with minimum biobased content.

Designated items

Minimum biobased content (%)

Fluid-filled transformers—synthetic ester-based 66

Fluid-filled transformers—vegetable oil-based 95

Metalworking fluids—general purpose soluble,

semi-synthetic, and synthetic oils

57 Metalworking fluids—high performance soluble,

semi-synthetic, and synthetic oils

40

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other tools such as life cycle analysis need to be employed to describe mental and economic benefits.

environ-Summary

USDA continues to support research, development, and commercialization ofbiobased products because of the positive impacts on many sectors in the fol-lowing ways: adding value to conventional crops, forestry materials and wastes;diversifying agriculture through alternative and new crop development; provid-ing new business opportunities and economic development in rural commun-ities; supporting the U.S industrial base with a reliable supply of renewable rawmaterials; helping government agencies and the public meet their environmentalstewardship, health and safety goals; and creating a new focus for research anddevelopment of products to meet the increasing demand The BioPreferredSM[10] program creates market pull and addresses obstacles to successful commer-cialization with Federal agency demonstrations of product performance, encour-aging development of industry standards and potentially reducing costs througheconomies of scale As more State governments adopt programs based onBioPreferredSM[10], the market pull will continue to expand The USDA Certi-fied Biobased Product voluntary labeling program will expand markets andincrease awareness about the benefits of biobased products

References

[1] Energy Independence and Security Act of 2007 (Pub L 110–140).

[2] Renewable Fuel Standard 2 (RFS2), http://www.epa.gov/otaq/fuels/renewablefuels/ index.htm (Last accessed March 2011).

[3] U.S Department of Agriculture, National Institute of Food and Agriculture, http:// www.nifa.usda.gov.

[4] U.S Department of Agriculture, Agricultural Research Service, http://www.ars usda.gov.

[5] National Ag-Based Lubricants Center, University of Northern Iowa, http://www uni.edu/nabl (Last accessed March 2011).

[6] U.S Department of Agriculture, Agriculture Research Service, http://www.ars usda.gov/research/themes/biopande.htm.

[7] In-Sik Rhee et al., “Field Demonstration of Biobased Hydraulic Fluids in Military Construction Equipment,” TARDEC Technical Report No #17682, U.S July 2007 Army Tank-Automotive Research, Development and Engineering Center, Detroit Arsenal.

[8] MIL-PRF-32073A, Performance Specification Hydraulic Fluid, Biobased, December

[12] ASTM D6866-11, 2010, “Standard Test Methods for Determining the Biobased tent of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis,” Annual Book of ASTM Standards, 2.01, ASTM International, West Conshohocken, PA.

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Patrick Laemmle1and Peter Rohrbach2

Application of ECLs and Today’s Legislation

ABSTRACT: Environmentally considerate lubricants (ECLs)—the so called

“bio oils”—were introduced in the mid 80s to minimize impact of lubrication

on the environment In the early 1990s the German RAL (Blue Angel) andthe Swedish Standard organisations defined corresponding specifications forECLs, other Eco-Labels followed In 2005 the European Community releasedthe directive 2005/360 defining the toxicity and ecotoxicity profile for ECLs,which qualifies them for the Euro-Marguerite For more than 20 years top tierECLs were used in mobile and stationary hydraulic equipment Well docu-mented field experiences not only demonstrate these lubricants contribute tothe fulfillment of the new laws but also meet technical requirements for thisequipment In this paper important EC Directives related to lubricants andthe protection of the environment are discussed and how they are imple-mented into national laws In addition the benefits of ECL in hydraulic equip-ment are addressed

KEYWORDS: ECL/ECLs, environmentally considerate lubricants, ability, bio oil(s), lubricant(s), top tier, eco label(s), EC directive(s), legislation,Blue Angel, RAL, Euro-Margerite

sustain-Introduction

Today’s modern society enjoys nature, and it makes sense that the wonderfulenvironment should be preserved as best as possible In daily work, legislationhas a great impact and environmental protection becomes a heavy burden onindustry’s shoulders These contradictory contexts of economy, technology, and

Manuscript received December 2, 2010; accepted for publication August 11, 2011; published online October 2011.

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environment are well known Especially these days the pressure on the entireeconomy has increased.

Decision makers have to cut costs to remain competitive while applying thelatest technology At the same time extra money should be spent for better envi-ronmental compliance on job sites An increasing requirement to be environ-mentally friendly can be observed in politics and in public and must be takeninto consideration

Modern Lubricants for Sustainable Companies

It is not so obvious but lubricants can have a great impact on machinery andthe environment and therefore on all stakeholders in and around this business.For its continuance and sustainability every company must be competitive inthree different aspects: economy, technology, and environment (see Figs 1–3).Economy

It is the target of every company to provide a certain profit to the owners andshareholders Only this profit enables the company to do investments and there-fore guarantees the continuance of the business

pro-FIG 1—Earth moving machine

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environment Only respect for the environment contributes to the sustainability

of the business Global trends such as reducing the carbon footprint are tant for our industries as well as reduced impact on the environment in general

impor-How Can a Lubricant Help to Achieve These Goals?

Top tier Environmentally Considerate Lubricants (ECLs) combine severaladvantages They are formulated such that the good biodegradability and lowtoxicity properties reduce their negative impact on the environment, so pollute

FIG 2—Railway machinery

FIG 3—Hydro power plant

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much less than traditional mineral oil lubricants Synthetic ester base oils incombination with excellent additive systems can provide longevity and lead tofewer oil changes In some systems life time fill has been achieved.

Legislation

In the mid 1980s interest in alternatives to the well-established mineral oilbased lubricants increased steadily At that time it was thought that refined veg-etable oils such as canola or sunflower oil could be taken as environmentallyfriendly lubricants Although these oils provide very good wear inhibition, theycan only be used in a very limited number of applications due to their weakthermo-oxidative stability If exposed to higher temperatures, sludge and lac-quer formation may occur with resultant risk of machinery damage, valve mal-functioning, and filter blockage The inherent chemical properties of naturaloils, or more generally of unsaturated esters, limit their use to “lost lubricant”applications such as in forestry chainsaws

The development of ECLs, which do not have these demerits, dates back tothat time Over the past 25 years this technology has been further optimized,and with more than 1 109operating hours accumulated so far, it has been pro-ven in practice that environmentally friendly along with top tier performanceare no longer inherent contradictions

Eco Labels

The German Blue Angel was the first eco-label that defined toxicity, ecotoxicity,and performance requirements for lubricants, and in particular hydraulic fluidswith minimal environmental impact in case of leakages The criteria are strin-gent: they define acceptable toxicity and ecotoxicity profiles not only for the fullyformulated lubricants but also for the additives and base fluid components.The Swedish Standard SS 15 54 34 eco-label also sets toxicity and ecotoxic-ity limits for each component and the entire formulation In the Nordic forestryindustry, only lubricants carrying the SS 15 54 34 eco-label are in use; also theyare used on job-sites where construction machinery has to be filled with

“approved hydraulic fluids.”

The most recently introduced eco-labels for lubricants are the Marguerite (EC Publication 2005/360/EC of 26 April 2005) and the USDA Bio-preferredTMlabel

Euro-EC Directives

The European Community (EC) has long addressed environmental protection

by releasing so-called EC Directives that legislate various aspects of this tious target The most important EC Directives and publications regarding theimpact of lubricants on the environment are as follows:

ambi-Directive 96/61/EC of 24 Sept 1996 concerning integrated pollution tion and control

preven-Directive 2000/60/EC of 23 Oct 2000 establishing a framework for nity action in the field of water policy

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Directive 2004/35/EC of 21 April 2004 on environmental liability with regard

to the prevention and remedying of environmental damage

Publication 2005/360/EC of 26 April 2005 on eco-label Commission decision

of 26 April 2005 establishing ecological criteria and the related assessment andverification requirements for the award of the Community eco-label [Euro-Mar-guerite] to lubricants

One goal of these directives is to ensure the prevention of negative impacts

on the environment by enforcing the application of state-of-the-art products.Another goal is to allocate the responsibility for any contamination to the pol-luter With Publication 2005/360/EC an EC eco-label for lubricants has beenintroduced It is the opinion of many that over the course of time the Euro-Marguerite label will take predominance as a reference; thus facilitatingEurope-wide the selection and use of ECLs

In the following, some details of these EC Directives and the Marguerite eco-label are outlined

Euro-Directive 96/61/EC of 24 Sept 1996 concerning integrated pollution preventionand control—The target of this Directive is the integrated prevention and control

Paragraph 11

“… ‘best available techniques’ shall mean the most effective and advancedstage in the development of activities and their methods of operation whichindicate the practical suitability of particular techniques for providing in princi-ple the basis for emission limit values designed to prevent.”

Article 3—General principles governing the basic obligations of the operator.Member States shall take the necessary measures to provide that the com-petent authorities ensure that installations are operated in such a way that: (a)all the appropriate preventive measures are taken against pollution, in particu-lar through application of the best available techniques; (b) no significant pollu-tion is caused

Related to lubricants it can be said that the “best available techniques” arethose which carry the Euro-Marguerite eco-label and in addition meet all per-formance requirements as defined by international or OEM specifications

Directive 2000/60/EC of 23 Oct 2000 establishing a framework for Communityaction in the field of water policy—Paragraph 1

Water is not a commercial product like any other but, rather, a heritagewhich must be protected, defended and treated as such [1]

Paragraph 3

The declaration of the Ministerial Seminar on groundwater held at TheHague in 1991 recognised the need for action to avoid long-term deterioration

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of freshwater quality and quantity and called for a programme of actions to beimplemented by the year 2000.

Article 1—Purpose

The Purpose of this Directive is to establish a framework for the protection

of inland surface water, transitional waters, costal waters and groundwaterwhich:

of substances which give rise to an equivalent level of concern

Annex VIII— Indicative list of the main pollutants

Paragraph 5

Persistent hydrocarbons and persistent and bioaccumulable organic toxicsubstances

Related to lubricants, in this case to additives and base fluid components,

“persistent” and “persistent and bio-accumulative” are important ecotoxicitycriteria as defined as follows:

“Bioaccumulation” means the process by which certain toxic substances(such as heavy metals and polychlorinated biphenyls) accumulate and keep onaccumulating in living organisms, posing a threat to health, life, and theenvironment

“Persistent, bio-accumulative and toxic (PBT)” means substances such asheavy metals that remain unaffected in the environment, travel up the foodchain due to their tendency to be soluble in fat but not in water, and are poison-ous to animals and/or plants

Substances that exhibit these characteristics are most problematic for theenvironment Lubricants that meet the Euro-Marguerite requirements are notcomprised of any such components Mineral oils are persistent hydrocarbonsand therefore cannot be used for formulating lubricants conforming to theEuro-Marguerite requirements

Directive 2004/35/EC of 21 Apr 2004 on environmental liability with regard tothe prevention and remedying of environmental damage—Article 1—Subjectmatter

The purpose of this Directive is to establish a framework of environmentalliability based on the “polluter pays” principle, to prevent and remedy environ-mental damage [1]

Article 3— Scope

Paragraph 1

This Directive shall apply to environmental damage caused by any of theoccupational activities listed in Annex III, and to any imminent threat of suchdamage occurring by reason of any of those activities damage to protected

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species and natural habitats caused by any occupational activities other thanthose listed in Annex III, and to any imminent threat of such damage occurring

by reason of any of those activities, whenever the operator has been at fault ornegligent

Article 5— Prevention action

Paragraph 1

Where environmental damage has not yet occurred but there is an nent threat of such damage occurring, the operator shall, without delay, takethe necessary preventive measures

immi-Article 6—Remedial action

Paragraph 1

Where environmental damage has been occurred the operator shall, out delay, inform the competent authority of all relevant aspects of the situationand take all practicable steps to immediately control, contain, remove or other-wise manage the relevant contaminants… the necessary remedial measures.The key point of Article 6 is that operators (in this case the polluters) arefully responsible at their own expense to take remedial action to minimize theimpact of any pollution

with-Publication 2005/360/EC of 26 Apr 2005 on eco-label Commission Decision

of 26 April 2005 Establishing Ecological Criteria and the Related Assessment andVerification Requirements for the Award of the Community Eco-Label (Euro-Mar-guerite) to Lubricants—This directive defines the acceptable toxicity and ecotox-icity profiles of all substances, additives and base fluid componentsincorporated in the lubricant [1] In addition, a set of sum rules limits the ac-ceptable combinations of additives and base fluid components “Fit forpurpose,” which includes long drain intervals and full protection of equipment,must obviously be met in all cases “Environmentally friendly” alone is not anadequate solution to the main objective of minimizing the impact of lubricants

on the environment

The following lubricant classes are explicitly mentioned

Hydraulic fluids shall at least meet the technical performance criteria laiddown in ISO 15380, Tables 2 to 5

Chain-saw oils shall at least meet the technical performance criteria laiddown in RAL-UZ 48 of the Blue Angel

Concrete release agents and other total loss lubricants

Two-stroke oils for marine applications shall at least meet the technical formance criteria laid down in the NMMA regulations

per-Two-stroke oils for terrestrial applications shall at least meet the EGD level

of technical performance criteria laid down

The benefit of this new eco-label is that it will simplify the situation forbuyers and users of lubricants and related products They no longer have to dis-tinguish between many different eco-labels When they buy products that carrythe Euro-Marguerite eco-label, they can be sure of being on the safe side regard-ing protection of the environment and their equipment

The responsibility for fulfilling the required environmental criteria has to betaken by the lubricants manufacturer and hence not by the end-user

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In addition, contrary to other eco-labels like the Blue Angel or SwedishStandard, the Euro-Marguerite label also addresses the renewability of rawmaterials Depending on the type of lubricant, the formulated products musthave a well-defined percentage of carbon content derived from renewable sour-ces like (vegetable) oils or (animal) fats.

USDA BioPreferred Program

The USDA BioPreferred program was determined by the US Secretary of culture stating the following: Biobased products are commercial or industrialproducts (other than food or feed) composed wholly or in significant part of bio-logical products including renewable agricultural materials (plant, animal, andmarine materials) or forestry materials [2]

As with any lubricant, appropriate monitoring and upkeep is recommended

as a part of any preventive maintenance Regular laboratory checks will indicateexcessive water or dirt content, for example, so that corrective action can betaken in good time

To conclude, the experience so far with appropriately formulated rapidlybiodegradable hydraulic fluids is as follows: they can be approved by OEMs forfactory and service fillings; oil drain intervals can exceed 10 000 operating hours

or 10 years (life time fill); and they can be used successfully even in demandingapplications, such as hydro power plants (see Table 1 that illustrates data forone such product line)

These products have also been found to perform well in the smallest to est construction machinery, from injection moulding machines to gigantic lockgate hydraulics, and only positive experience has been reported

larg-Conclusion

The European Community gives high priority to protection of the environment.The EU Parliament and Counsel address this issue in a series of directives, coveringaspects such as integrated pollution prevention and control as well as the liability

of pollution originators In the near future the European Union member states willhave to implement and enforce these directives through their national legislation.Related specifically to lubricants, the EU Commission has established eco-logical criteria and the respective assessment and verification requirements for

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awarding the EU eco-label (Euro-Marguerite) to lubricants In the future thisnew eco-label, recognized throughout Europe, will enable buyers and users toselect lubricants with only minimal environmental impact in case of a leakage.The USDA biopreferred program was created by the Farm Security and Ru-ral Investment Act of 2002 (2002 Farm Bill) to increase the purchase and use ofbiobased products The United States Department of Agriculture manages theprogram BioPreferred includes a preferred procurement program for Federalagencies and their contractors, and a voluntary labelling program for the broadscale consumer marketing of biobased products.

The Bottom Line

Over the past 25 years a new lubricant technology has been developed: mentally Considerate Lubricants (ECLs) that minimize environmental impact

Environ-in case of Environ-incidental spillages Today’s top performers Environ-in this lubricant classmeet or often exceed the performance requirements set by the OEMs Further-more, their long drain periods minimize lubricating costs when summed upover the equipment lifespan

References

[1] EUR-Lex Access to European Union Law, http://eur-lex.europa.eu/LexUriServ/Lex UriServ.do?uri=CELEX:32004L0035:EN:HTML (Last accessed Sept 15 2011) [2] USDA BioPreferred Program, http://www.biopreferred.gov/ (Last accessed Sept 15 2011).

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Govind Khemchandani1and Martin R Greaves2

Characteristics of PAG Based Bio-Hydraulic Fluid

ABSTRACT: Regulatory drivers both in the U.S and in the European Unionare attempting to promote the use of biodegradable lubricants in the market-place A base fluid that uses the first ever combination of biodegradable poly-alkylene glycol (PAG) with a high oleic canola oil was developed to meetenvironmental accreditation standards This combination utilizes the PAG to

“upgrade” the vegetable oil in hydraulic fluid formulation and provide a basefluid that can solubilize the oxidation by-products and provide better depositcontrol compared to straight general purpose fluids that are based on vegeta-ble oils A general purpose bio-hydraulic fluid that use a blend of PAG andhigh oleic canola oil has shown enhanced performance characteristics in twocritical tests namely an oxidation test (ASTM D 2893 B) and a hydraulic vanepump test (ASTM D 7043) These two tests clearly differentiate the superiorattributes of the PAG-based bio-hydraulic fluid compared to a widely use gen-eral purpose biodegradable hydraulic fluid in the market place

KEYWORDS: oxidation stability, polyalkylene glycol, vegetable oil, gradability, wear, ester

biode-Introduction

Many original equipment manufacturers in Europe in the last decade haveshown a growing interest in high performance biodegradable polyalkylene gly-col (PAG) base stocks This has led to the development of new biodegradablePAG base fluids [1,2] Since then Europe has moved towards a consensus thatbio-lubricants should be derived from renewable feed stocks In 2005, Europeintroduced the new ECO-label scheme that defined criteria for lubricants to beawarded the ECO-Label Two aspects of these criteria are environmental

Manuscript received November 18, 2010; accepted for publication September 7, 2011; published online October 2011.

1 The Dow Chemical Company, Freeport, TX 77541, gvkhemchandani@dow.com

2 The Dow Chemical Company, Horgen, CH-8810, Switzerland, mrgreaves@dow.com Cite as: Khemchandani, G and Greaves, M R., “Characteristics of PAG Based Bio-Hy- draulic Fluid,” J ASTM Intl., Vol 9, No 2 doi:10.1520/JAI103605.

17

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performance and technical performance in which the fluid must meet the mum specifications defined in ISO-15380 For bio-hydraulic fluids, formulationsneed to be biodegradable but should also contain a minimum of 50 % renewablecarbons Formulators of hydraulic fluids meeting these aforesaid parametershave several choices of base oils that they can use for formulating fluids asshown in Fig 1 Some of these are renewable base oils such as natural esters(vegetable oils), but others such as PAGs are not based on renewable feedstocks Some synthetic esters, such as polyol oleate esters, are renewable butmany synthetic esters are not.

mini-Vegetable oils and high oleic vegetable oils are often the first choices for mulating general-purpose fluids that are required to have a high level of renew-ability and biodegradability [3] These are typically low cost products designedfor applications where reservoir temperatures are low (<70C) Top-tier fluidsare usually formulated with saturated synthetic esters, but many of these are notbased on renewable feed stocks Certain performance limitations of vegetable oilbase stocks are poor oxidative stability due to bis-allylic protons in the fatty acylchain, deposit forming tendency, low-temperature solidification, and poorhydrolytic stability [4] Many research efforts are directed toward improving theoxidative and low-temperature stability of vegetable oils by chemical modifica-tion of the base oil, blending with functional fluids like PAO (poly alpha olefins)and additive response studies [5] However, high performance bio-hydraulic flu-ids use synthetic esters as base fluids along with additives for further improve-ments in oxidation stability and low temperature fluidity [6] Synthetic esterbased formulations are highly desired for mobile equipment applications Tooptimize cost and performance, formulators today often blend two or more ofthese base stocks with vegetable oils In the present paper, PAGs are blendedwith high oleic canola oil such that the canola oil is the dominant base fluid tomaintain 50 % renewable carbons This combination utilizes the PAG to

for-“upgrade” the vegetable oil in hydraulic fluid formulation and provide a basefluid that can solubilize the oxidation byproducts, allowing equipment to operate

in a clean environment and reduce problems such as deposit and varnish

FIG 1—Choice of base oils for formulating bio-hydraulic fluids

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formation and servo-valve sticking The new bio-based formulation not only vides better deposit control compared to straight vegetable oils but is also biode-gradable and derived from a high percentage of renewable feedstock [7–9].

pro-A bio-hydraulic fluid formulation (Biolube D) was developed using a blend

of high oleic canola oil (in which the oleic acid fraction content was 75 %) and aPAG that is derived from a homo-polymer of propylene oxide The formulationalso contained commonly used hydraulic oil additives such as antiwear and oxi-dation inhibitors The selection of additives for hydraulic fluids is well docu-mented in the industry [10,11] By blending different- ratios of PAG and higholeic canola oil in a formulation it is easy to adjust the renewable carbon con-tent to achieve 50 % renewable carbons

Objective for Competitor Product Evaluation

The primary purpose of this study was to benchmark Biolube D against threeformulated bio-hydraulic fluids from market with different base oil composi-tions The chemistries of the bio lubricants tested are as follows:

Biolube A formulation that comprises a canola oil in which the canola oilcontains approximately a 60 % oleic acid fraction

Biolube B formulation that comprises a canola oil in which the canola oilcontains approximately an 82 % oleic acid fraction

Biolube C formulation comprising a blend of high oleic canola oil and a urated synthetic ester in which the saturated ester is the major component.All these fluids are formulated bio-hydraulic fluids having a renewable car-bon contents that are greater than 44 %

sat-Two key aspects of the evaluation are as follows:

1 To benchmark the performance of Biolube A against Biolube D Theseproducts are marketed for stationary equipment and regarded as

“general purpose” fluids They are not intended for mobile equipmentwhere high sump temperatures and severe operating conditions areexperienced

2 Assess the performance of Biolubes B and C, which are targeted for bile equipment operating at higher equipment temperatures Biolube C

mo-is especially of interest because it mo-is recognized as a “top-tier” fluid in themarket place

Comparative studies with Biolubes B and C will provide useful data as part

of this research program and may point to future research directions in ing top-tier bio-hydraulic fluids

develop-Experiments: Performance Evaluation Test Methods

To compare bio-hydraulic fluids A–C with Biolube D, four main chemical tests were carried out

physico-Kinematic Viscosity and Viscosity Index

Kinematic viscosities at 40C and 100C were measured on a Stabinger ter using ASTM D-7042 Viscosity index was calculated using ASTM D-2270

viscome-J_ID: DOI: Date: 29-November-11 Stage: Page: 19 Total Pages: 8

KHEMCHANDANI AND GREAVES, doi:10.1520/JAI103605 19

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Eaton (Vickers) Vane Hydraulic Pump Testing

Hydraulic wear performance testing was conducted using Eaton (Vickers) V-104Cpump housing and Connestoga ring and vanes as explained in ASTM D-7043(Standard Test Method for Indicating Wear Characteristics of Petroleum andNon-Petroleum Hydraulic Fluids in a Constant Volume Vane Pump) However, amodified version of this procedure [12] was used with the key modifications as fol-lows First, a reservoir capacity of 1 gal was used (5 gal is recommended in themethod) Second, a comprehensive cleaning procedure was employed before eachtest in which the equipment is stripped down, cleaned, rebuilt, and flushed withnew test fluid In this way, contamination is minimized from the fluid that waspreviously evaluated in the equipment Each hydraulic pump experiment was con-ducted at a bulk fluid temperature of 65C for 100 h, 1200 rpm (rpm), and a pres-sure of 2000 pounds per square inch (psi) whereupon the weight loss of the vanesand the ring (cam) were recorded and reported as total weight loss In addition,the condition of the fluid before and after each experiment was recorded by meas-uring its kinematic viscosity change at 40C

Corrosion Inhibition

Corrosion inhibition performance was measured using both ASTM D-665 A ionized water) and ASTM D-665B (synthetic sea water) test methods over a 48-hperiod A pass or fail rating was given

(de-Oxidation Testing

Oxidation performance was assessed using experimental conditions described

in ASTM D-2893B (“Oxidation Characteristics of Extreme Pressure LubricationOils”) However, the data were reported in two different ways [12] First, thechange in kinematic viscosity at 40C was reported after the 13-day test periodinstead of at 100C Second, the test was extended beyond the 13-day test period

to 90 days (2160 h) or until the kinematic viscosity of the fluid at 40C hadincreased by more than 50 % compared to its initial starting value The timetaken for the fluid to reach a 50 % viscosity increase was measured and recorded

as t50.The results are shown in Fig 2 No other test parameters were measured.The visual appearance and condition of the fluid after the oxidation test wasalso noted For better visual effects, oxidized fluids were transferred from theoriginal test tubes to 6 cm long, 1.5 cm o.d glass tubes The sticky varnish de-posit in the original glass oxidation tube is shown for Biolube A in Fig 3 Bio-lube B was dark and contained visual deposits Biolube C was dark andtranslucent with no deposits Biolube D was yellow, clear and translucent Fig-ure 3 shows pictures of Biolube A versus Biolube D because one of the objec-tives of the paper was to compare Biolube D with Biolube A

Results and discussions

Table 1 summarizes the viscometric and corrosion performance data Biolubes

A, C and D are all ISO VG-46 classified fluids, whereas Biolube B is an ISO VG-68

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FIG 2—Oxidation stability of bio-hydraulic fluids.

FIG 3—Deposit control visualization

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fluid All products have high viscosity indices (and greater than 200) exceptfor Biolube C, which has a significantly lower value (141) This low value is nottypical of top-tier fluids In ferrous corrosion tests, Bio-lubes A—C failed thesalt water corrosion test after 48 h, whereas new Biolube D passed This sug-gests the Bio-lubes A–C are not well protected with an optimum corrosion inhib-itor Hydraulic equipment, particularly operating near waterways would benefitfrom protection from salt water corrosion.

Eaton (Vickers) V104C pump performance test data is shown in Table 2.This test is an industry standard test for routinely screening anti-wear hydraulicperformance over a 100 h test period All products demonstrated excellent anti-wear properties This is very typical of vegetable and ester containing fluids inwhich the film forming benefits are widely known In addition to measuringantiwear properties, the condition of each fluid was evaluated after the test toassess if any degradation had occurred Table 2 shows the changes in kinematicviscosity after the 100 h test period Surprisingly, Biolubes A and B show a vis-cosity reduction (12-13 %) Although the reason for this was not studied, wespeculate that these formulations contain a high molecular weight viscositymodifier that shears under high speeds In contrast, Biolube C shows anincrease in viscosity (18 %) New Biolube D shows only a 2 % viscosity change.The viscosity change of 12 % to 18 % of the Bio-fluids A–C is substantial, and it

is expected that equipment used in the field could be prone to excessive wear,

TABLE 1—Physico-chemical properties of bio-hydraulic fluids.

Test Method Biolube D Biolube A Biolube B Biolube C Viscosity at 40 C, cSt ASTM D7042 46.7 45.6 67.6 44.1 Viscosity at 100 C, cSt ASTM D7042 9.9 10.2 13.3 7.6

ISO viscosity grade ISO VG Standard 46 46 68 46 Rust prevention,

deionized water 48 h

Rust prevention,

sea water 48 h

TABLE 2—Hydraulic pump performance data.

Test Method Biolube D Biolube A Biolube B Biolube C Vickers vane V104C test,

total ring and vane weight

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cavitation, and pump failure if the fluids are not used within their intended cosity limits.

vis-Oxidation stability data are shown graphically in Fig 2 ASTM D2893B is

an oxidation test that measures the change in viscosity (KV100) over a 13 dayperiod The test can often differentiate the performance of lubricants in a shorttime The oxidative stability of the fluids was also extended beyond 13 days to amaximum of 96 days, and the time taken for the fluids to increase in KV40 by

50 % (t50) was measured For Biolubes A and D, t50values are 11 and 18 days,respectively For Biolubes B and C, t50values are 21 and 96 days, respectively.Biolube C shows excellent performance, and this is believed to be due to thehigh content of saturated synthetic ester in the fluid

Oxidation performance is known to be a key differentiator of modern hydraulic fluids When one compares the performance of each general-purposebio-hydraulic fluid—Biolube A and Biolube D–the induction time is significantlybetter for Biolube D because there is a rapid increase in viscosity of Biolube Aafter only 11 days of testing After 11 days, its viscosity changed from 45.6 cSt to83.1 cSt and hence shows a viscosity increase of 82 % compared to Biolube Dwith a viscosity change of 23 % This suggests that Biolube D will providegreater fluid longevity in equipment However, both fluids should not be oper-ated at these high temperatures (95C) under continuous operation but at lowertemperatures Biolube D has been recommended for use up to 70C for continu-ous service The high oleic acid fraction content of the vegetable base oil in Bio-lube B and the presence of a saturated synthetic ester component in Biolube Ccan be the reason for their higher values of t50 Moreover, these top-tier fluidshave been designed for use in mobile equipment where higher reservoir temper-atures are often experienced

bio-Finally, we examined the potential of Biolube D to form varnish compared

to Biolube A by observing the deposits present after the completion of the tion test This has been shown in Fig 3 Biolubes A–C darkened after the testhaving started it as pale yellow translucent fluids Biolube A displayed sludgeparticles at the bottom of the tube and soft film formation (varnish) at the sides

oxida-of the tube Biolube D maintained a clear translucent appearance throughoutthe test with no sludge and varnish formation It is hypothesized that the oxida-tion products of Biolube D are soluble in the polar PAG base oil, and this couldhelp eliminate or reduce sludge and deposit formation that is common for lubri-cants containing vegetable and ester oils Fluids that offer greater cleanlinessthrough better deposit control can minimize or eliminate common problemssuch as filter blockages and servo-valve sticking

Conclusions

Bio-hydraulic fluid D has been examined against Bio-hydraulic fluids A–C in draulic pump tests, corrosion, and oxidation experiments using industry stand-ard methods All fluids demonstrated excellent wear performance in a rotaryvane hydraulic pump test An evaluation of the condition of each fluid after the

hy-100 h test period showed Biolube D exhibited superior stability All three benchmark products showed significant viscosity change

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In oxidation experiments, Biolube D remained clear and deposit free whencompared to Biolube A A key observation from this work is that the inclusion

of a PAG into a traditional vegetable oil containing formulation can significantlyimprove deposit control and ultimately equipment reliability

Future work

Biolube C showed excellent thermo-oxidative stability and for this reason ispositioned as a top-tier fluid for mobile equipment Nonetheless, its low viscos-ity index and poor stability in a vane pump test is notable and suggests improve-ments in these types of fluids are needed Activities are ongoing to in author’slab to develop new fluids that balance performance and cost

Acknowledgments

The writers thank many colleagues and Kathryn Christman in The Dow ChemicalCompany who conducted the tests and performance measurements in Freeport, TX.References

[1] Van Voorst, R., and Alam, F., “Polyglycols as Base Fluids for Environmentally-Friendly Lubricants,” Journal of Synthetic Lubrication, Vol 16, No 4, 2000, pp 313–322 [2] Beran, E., “Structurally Modified Polyglycols as Biodegradable Base Stocks for Syn- thetic Lubricants,” Journal of Synthetic Lubrication, Vol 20, No 1, 2003, pp 3–14 [3] Kling, G H., Tharp, D E., Totten, G E., and Webster G M., Ecological Compatibility in Handbook of Hydraulic Fluid Technology, Marcel Dekker, New York, 2000, pp 427–468 [4] Kling, G H., Bio-Based industrial Fluids and Lubricants, Erhan, S Z., and Perez, J M., Eds., AOCS, Champaign, IL, 2002, Chap 1, pp 1–19.

[5] Rudnick, L R., “Synthetics,” Mineral Oils, and Bio-based Lubricants, CRC, New York, 2006, Chap 22, pp 361–387.

[6] Boyde, S., “Hydrolytic Stability of Synthetic Ester Lubricants,” Journal of Synthetic Lubrication, Vol 6, No 4, 2006, pp 297–312.

[7] Greaves, M., “Controlling Deposit Formation Using PAG Lubricants,” ings, Vol 59, No 4, 2006, pp 25–26.

Compound-[8] Canter, N., Upgrading Biodegradable Lubricant Performance, Tribology and cation Technology, Society of Tribologists and Lubrication Engineers, Park Ridge,

Lubri-IL, 2009, pp 14–15.

[9] Khemchandani, G., “Tribological Characteristics of PAG Based Synthetic Turbine Fluid,” TAE, 17th International Colloquium Tribology, Stuttgart/Ostfildern, Ger- many, Jan 19–21, 2010, pp 99.

[10] Roby, S H., Yamaguchi E S., and Rayson P R., Lubricant Additives for Mineral Oil-Based Hydraulic Fluids in Handbook of Hydraulic Fluid Technology, Marcel Dek- ker, New York, 2000, pp 795–823.

[11] Duncan, C., Reyes-Gavilan, J., Costantini, D., and Oshode, S., “Ashless Additives and New Polyol Ester Base Oils Formulated for Use in Biodegradable Hydraulic Fluid Applications,” Lubr Eng., Vol 58, No 9, 2002, pp 18–28.

[12] Greaves, M., and Knoell J., “A Comparison of the Performance of Environmentally Friendly Anhydrous Fire resistant Hydraulic fluids,” J ASTM Int., Vol 6, No 10, 2009.

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KEYWORDS: bio-no-tox, heat capacity, fuel economy, drain, polyglycol,polypropylene glycol, polyalkylene glycol, polybutylene glycol, BAM test,AlSi-liner wear, DLC, SRV, slip-rolling, Stribeck curve

Introduction

In the future, engine oils will more and more determine the functional ances and environmental properties of the vehicle through its contribution tofuel economy and to minimize or avoid their impact on durability of particulatefilters and catalysts [1]

perform-Manuscript received September 14, 2010; accepted for publication April 26, 2011; published online July 2011.

1 BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D

12200 Berlin, Germany, e-mail: mathias.woydt@bam.de

Symposium on Testing and Use of Environmentally Acceptable Lubricants on 16 ber 2010 in Jacksonville, FL.

Decem-Cite as: Woydt, M., “Polyalkylene Glycols as Next Generation Engine Oils,” J ASTM Intl., Vol 8, No 6 doi:10.1520/JAI103368.

25

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Historically, polyglycols were commercialized by end of the 1920s (UnionCarbide with U.S 1,633,927; I.G Farben with U.S 1,921,378) Engine oils based

on polyglycols are not new and were applied by the U.S Air Force [2,3] whenused in aircraft engines of P-38, P-47, P-51 and B-25 (g100 C 18.5 mm2/s) inorder to avoid soot deposits in the oil cooler and for pourpoint reasons (winterstarts) [4]

The polyglycols disclosed in patent applications (FR 2 792 325, U.S.6,194,359, DE 10 2005 011776) of the last 10 years follow a metal-free, ash-free,and polymer-free strategy

The polyglycol-based formulations in Table 1 are also all metal-free, free, and polymer-free

ash-This paper presents briefly some properties, which have nowadays attractedthe automotive original equipment manufacturers (OEMs)

Structure-Property Rules

Different from hydrocarbon-based oils, polyol-esters and polyalkylene glycols(PAGs) synthetic oils contain an “oxygen heteroatom” at regular intervals intothe hydrocarbon chain

For many decades, neopentyl glycol ((2,20-dimethyl)-1,3-propanediol), methylolpropane (1,1,1-tris(hydroxymethyl)-propane), and pentaerythritol (2,2-bis(hydroxylmethyl)-1,3-propanediol) have been known and used as alcoholiccompounds of polyol-esters produced from carboxylic acid containing moieties.Also, dibasic esters such as adipates (butane-1,4-dicarboxylic acid) are beingused as base oils and additives

tri-PAGs are prepared by the reaction of epoxides, usually ethylene oxide, ene oxide (PO), or butylene oxide with an active hydrogen containing compound,usually an alcohol or water, in the presence of a group 1 basic catalyst, e.g., so-dium or potassium oxide Polymers with statistically distributed alkylene oxidegroups are made by the use of a mixture of different alkylene oxides Separateadditions of oxides lead to the formation of block copolymers (see Fig 1) PAGsare generally denominated as copolymers of ethylene oxide (EO) and PO Polypro-pylene glycols (PPG) are generally denominated as homopolymers for PO only.PAGs have at least one functional (OH) group at the end of the moleculeand are generally recognized as alcohols Monofunctional starters, like forinstance n-butanol, produce monofunctional alcohols with molecular weights,which vary between 500 and 1800 Da, and are often used as base oils for lubrica-tion purposes

propyl-Due to the oxygen polarity, PAGs have solvent properties somewhat differentfrom those of hydrocarbons The carbon–oxygen bond is stronger than thecarbon–carbon bond The polar nature of PAGs, in each monomer, gives the back-bone a strong affinity for metal surfaces, thus defining the lubricity under mixed/boundary lubrication Literally speaking, the polyglycol base oil is here theextreme pressure (EP) and/or anti-wear additive ! Because of their chemical struc-ture, PAGs are clean burning and do not leave any residue upon combustion.The molecular structure of PAGs that are suitable as alternative engine oils

is represented in Fig 2

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The molar mass distribution of the same polypropylene glycol base oil wasdetermined by two different techniques (Fig 3).

The molecular weight distribution (MWD) of PAGs is determined by means ofroom temperature (RT) gel permeation chromatography (GPC) (see Fig 4) Theestimated applicable range of the used procedure is 100–10 000 Da For this test,

150 6 20 mg of sample is weighed into a 20 ml vial, and 10 ml of tetrahydrofuran(THF) (HPLC grade, LabScan) is added The GPC analysis is calibrated using amixture of reference PAGs of known molecular volume (1.5 wt % in THF).Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)mass spectrometry is an emerging technique offering a great promise for thefast and accurate determination of a number of polymer characteristics Due tothe low molar mass of the polymer, the molar mass distribution of the PPGdescribed above is easily determined to be 58 g/mol (repeating units) from thepeak-to-peak mass increments (see Fig 4) Each unit of 58 g/mol corresponds to

1 mol of PO

The molar mass distribution of a PAG (n-butanol initiated random mer of EO and PO) can be represented in a two dimensional spectrum [5],which represents a population intensity diagram of the moles of EO and themoles of PO applying (see Fig 5)

copoly-Both high-end techniques are used to assess the quality of each batch and

to bear the evolution of functional properties based on the analysis of oil ples taken from engines

sam-FIG 1—Basic molecular structure of polyglycols

FIG 2—Visualisation of the oxygen (red) polarities in polyglycol backbones

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Hydraulic oils represent the largest volume of environmental friendly lubricants,which are often labeled with an environmental label, such as the Euromargerite(EC/2005/360) First automotive OEMs argue about such a label for engine oils Twomain factors need to be considered when classifying substances and preparations

FIG 3—MWD of a polypropylene glycol —PPG (molecular weight: Mn¼ 1037 Da) bymeans of GPC

FIG 4—MALDI-TOF spectrum for n-butanol initiated PO random copolymer (PPG)

WOYDT, doi:10.1520/JAI103368 29

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(EC/1999/45, including amendment EC/2008/6) in relation to symbol “N,” especiallyfor formulations:

–ready biodegradability according to organisation for economic operation and development (OECD) 301x with a biodegradation of >60 %and

co-–three aquatic toxicities (OECD 203 fish, OECD 202 daphnia, and OECD

201 algae) with values of >100 mg/l

The European directive EC/2006/8, amended in January 2006, now alsoincludes R59 “Dangerous for the ozone layer.” As an outcome of several Euro-pean funded R&D-projects (Erebio, Ibiolab, and Cleanengine), it can be con-cluded that carefully selected polyglycol base oils exceed as base oils the setlimits for bio-no-tox of the European preparations directive and also, based onproprietary additives, as fully formulated engine oils

The biodegradation of different, hydrocarbon-based factory fill engine oilswere determined in the frame of the aforementioned EC funded R&D projects

It came out that the biodegradations according to OECD 301B/F rangedbetween >30 and <50 % Some of these factory fill (FF) formulations failed sig-nificantly in respect to algae toxicity according to OECD 201

In contrast, the polyglycol-based formulations in Table 1 meet the eco-toxrequirements of the European preparations directives The high values for bio-degradation in Table 1 of the different polyglycols have to be noted, and also, inview of aquatic toxicity, the additives need to be carefully selected

FIG 5—2D plot of the distribution monomer units of a butanol initiated EO–PO dom copolymer [6]

ran-J_ID: DOI: Date: 29-November-11 Stage: Page: 30 Total Pages: 22

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Oxidation Resistance

Some publications of the past rated the polyglycols as less resistant against hightemperature oxidation than synthetic esters or polyalphaolefin (PAOs) Fromrecent work [7] in road testing, it can be concluded that this perception is nolonger valid in front of the general evolution of the polyglycol base oil technol-ogy and the identification of specific anti-oxidants and additives

In order to reduce test costs, the procedure of the iron catalyzed oxidationtest (ICOT) test (GFC Lu 36T 03), as described in Ref [6], was modified to thetest oxydation catalyse´ (TOC)-test (AFNOR D55 3099); even then, the test princi-ples remained unchanged The highest oxidations resistance is now the “class 3”with >96 h, which corresponds to a drain interval of >30 000 km for dieselengines with particulate filter and regeneration mode

Figure 6 displays the latest engine evaluated polyglycol formulations in tion to a synthetic factory fill engine oil of Renault sulphur, ash, phosphorus(SAS)

rela-All polyglycols in Fig 6 were found to meet the 96 h criteria and exceed this,

as well as presented no drop in viscosity through oxidation The evolution in cosity of the polyglycols depends from the additive package, but the stabilityjustifies lower initial viscosities, which will translate to improved fuel economy.The B10 and low viscosity E72 are the formulations with a very stable oxidationresistance for extended drains Their viscometric values are retained over entiredrain period

vis-Road testing [9] of PAG formulations based either on PPG-monobutyletherand polybutyleneglycol (PBG)-monobutylether proved a suitability for drains of

at least 40 000 km (3.2 L V6 TFSI) Oxidation tests according to TOC test(AFNOR D55 3099) revealed the class 3 performance level (>96 h), which corre-sponds to >30 000 km of drain for turbodiesel engines with particulate filters(see Fig 6) The total acid number (TAN) at 96 h was 1.54 mg/KOH/g for theB20 and 1.43 mg/KOH/g for the B48 The two polyglycol formulations displayed

no viscosity loss caused by oxidation, thus remaining quite stable over test thetime and justifying lower initial viscosity grades

The acidic degradation products are characterized by carbonyl linkages,which can be measured via several analytical techniques The decompositioncan be delayed and prevented by the addition of a tailor made antioxidant pack-age [4]

Figure 7 represents the increase in carbonyl level (expressed in meq C¼O/gPAG) as a function of time, measured during road testing [7,8] After 335 h, thecarbonyl level in the oil has increased to about 0.025 meq C¼O/g, which corre-sponds to 735 ppm This number is generally recognized as low and corre-sponds to a TAN of less than 2.0 mg KOH/g These are similar values to thosedetermined in the TOC test in Fig 6

Tiêu đề	Testing and Use of Environmentally Acceptable Lubricants
Tác giả	In-Sik Rhee
Người hướng dẫn	Dr. In-Sik Rhee, JAI Guest Editor
Trường học	ASTM International
Chuyên ngành	Engineering
Thể loại	Technical Paper
Năm xuất bản	2012
Thành phố	West Conshohocken

Định dạng
Số trang	205
Dung lượng	47,51 MB