Exploratory Studies on Borate Esters as Drop Point Enhancers · 2018. 6. 13. · 9 Results & Discussion Physicochemical properties of Greases Property Method Gr-1 Gr-2 Gr-3 Gr-4 Appearance

Exploratory Studies on Borate Esters as Drop Point Enhancers

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IOC, R&D Centre, Faridabad

Vennampalli M., Pokhriyal N.K., Bansal V. R., Saxena D. and Ramakumar S.S.V.

NLGI 85th Annual Meeting, June 9-12, 2018, Coeur d’Alene, ID, USA

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Lay-outPerspective & Objective Introduction -Complexing agentsComplexing with Boric acid / Ester

Lab Synthesized Borate Ester (LBE) Commercial DPE (Borate Ester) PackagesExperimental – Grease ManufacturingResults & Discussion -Physicochemical properties of GreasesStorage stability studiesSEM studiesSEM - EDX studiesConclusions & Way Forward

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Perspective & Objective

From NLGI Grease Production Survey 2017

Conventional Li-Complex greasesØDibasic acidsØMore LithiumØHigh Processing TempØExpensive

üSimple & cheaper acids/complexingüNo extra Lithium

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Boric acid, B(OH)3Ø Bronsted acid - Weak proton donorØ Lewis acid - Accepts electron pair

Introduction - Complexing agents

The affinity of Boric acid to from coordinated complex with alcohol is utilized

B(OH)3 + 3ROH → B(OR)3 +3 H2O

Borate esters {B(OR)3} Ø Condensation reaction of boric acid and alcohol

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Boric acid requires more transition

energy

Ø Agent - Boric acidØ Complex - Coordinated ComplexØ Stage - Initial stageØ Advantage - Established, reliableØ Limitations - Energy, Cost ,Time

Complexing with Boric acid

insitu route

Gareth Fish, et al., NLGI Spokesman, Vol 82, page 50-60, Mar/Arp 2018Joseph P. Kaperick, et al., NLGI Spokesman, Vol 81, page 36-45, Nov/Dec 2017Deshmukh, V. and Rajput, B.K., 82nd Annual NLGI Meeting, ID, June 2015John Lorimor, Presented at NLGI 76th Annual Meeting, Arizona

Borate ester being an activated ester requires lower transition energy

route

Ø Agent - Borate EsterØ Complex - Coordinated ComplexØ Stage - Finishing stageØ Advantage - Energy, Cost ,TimeØ Limitations – Odour, Reliability

DPE

/ Ester

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Lab Synthesized Borate Ester (LBE)

Ø Inputs screening – Alochols: Linear, branched,aromatic hydroxy alcohols, diols, etc.

Ø Synthesis - Reaction of Boric acid with selectedbranched alcohol

Ø Characterization - 1H, 13C, 11B NMR, IR spectraand flame test

Key Benefits Ø Home grown technologyØ Control over inputsØ Reduce costØ Tailor madeØ Safety

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Commercial DPE (Borate Ester) Packages

1. Borate esters / amines2. Borate esters / amines mixed with ZDDP 3. Borate esters with EP package

Available in three classes

Class 2 - ZDDP enhances dropping point by forming lithium dithiophosphate

LiOH.H2OLithium dithiophosphate

+ zinc oxide + water

Sivik M. R. Zeitz and J. B. Bayus D. “Interactions of ZDDP with Li-12 HSA Grease” , NLGI AGM 2001, Florida

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Experimental – Grease Manufacturing

Gr-1: Lithium grease - insitu route– Boric acid

Gr-2: Lithium grease - insitu route – Lithium Borate

Gr-3: Lithium grease - Base grease

Gr-4: Base grease (Gr-3) - DPE route - with LBE at 2 wt%

Gr-5: Base grease (Gr-3) - DPE route - commercial DPE package 1 at 2 wt%

Gr-6: Base grease (Gr-3) - DPE route - commercial DPE package 2 at 2 wt%

Gr-7: Base grease (Gr-3) - DPE route - commercial DPE package 3 at 2 wt%

Gr-8: Base grease (Gr-3) - DPE route - with LBE at 1.4 wt% + 0.6 wt% ZDDP

All greases were prepared by BATCH Process in pressure reactor and were NLGI Grade 2

Evaluation plan

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Results & DiscussionPhysicochemical properties of Greases

Property Method Gr-1 Gr-2 Gr-3 Gr-4

Appearance Visual SmoothBrown

SmoothBrown

SmoothBrown

SmoothBrown

Wt % of Li-12 HSA Recipe 12.0 12.0 9.5 9.5Drop Point (°C) ASTM

D 2265 258 261 202 269Unworkedpenetration (0.1 mm)

ASTMD 217 286 285 268 280

Worked penetration, (0.1 mm)

ASTM D 217 291 288 270 282

Mechanical stability, units change, 105

strokes

ASTM D 217 +28 +29 +18 +21

Roll Stability, 16hrs, % change from P60

ASTM D 1831 13.3 12.0 7.5 8.3

Copper corrosionASTM D 4048 Pass Pass Pass Pass

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Property Method Gr-5 Gr-6 Gr-7 Gr-8 Appearance Visual Smooth

BrownSmoothBrown

SmoothBrown

SmoothBrown

Drop Point (°C) ASTM D 2265 253 261 270 276

Unworkedpenetration,(0.1 mm)

ASTM D 217 285 282 282 280

Worked penetration(0.1 mm)

ASTM D 217 290 288 282 284

Mechanical stability unit change, 105

strokes

ASTM D 217 +36 +33 +23 +21

Roll Stability, 16hrs, % change from P60

ASTM D 1831 15.7 14.2 9.1 8.0

Copper corrosion ASTM D 4048 Pass Pass Pass Pass

Results & Discussion contd.Physicochemical properties of Greases

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Results & Discussion contd.Storage stability studies

Property Method Gr-5 Gr-6 Gr-7 Gr-8

Appearance Visual SmoothBrown

SmoothBrown

SmoothBrown

SmoothBrown

Drop Point (°C) ASTMD 2265 251 260 268 272

Unworked penetration (0.1 mm)

ASTM D 217 290 285 280 282

Worked penetration (0.1 mm)

ASTM D 217 292 288 278 286

Mechanical stability unit change ,105 strokes

ASTM D 217 +40 +36 +25 +20

Roll Stability, 16hrs, % change from P60

ASTM D 1831 17.1 14.5 11.2 9.8

Copper corrosion ASTM D 4048 Pass Pass Pass Pass

Drop point was found consistent in all greases were during one year of storage

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Characteristic Lithium soap fibers

Fine and dense complex soap fibers

Results & Discussion contd.

SEM studies

How it works-Mechanism?

Results & Discussion contd.SEM – EDX

(Energy Dispersive X-Ray Analysis)

Structural proof – SEM EDX

SEM/EDX ANALYSIS OF BORON : A CASE STUDY; Linda Ingemarsson & Mats Halvarsson,HighTemperature Corrosion Centre (HTC) Chalmers University of Technology , 2011

Conclusions & Way Forward

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Ø Synthesis and characterization of Borate ester with a branchedalcohol was successfully done in laboratory.

Ø LBE @ 2.0 wt% worked as a DPE in Lithium 12-HSA Grease.Ø Around 60° C increase in drop point of Lithium base grease was

achieved.Ø Performance of LBE was found comparable to that of the

commercial DPE packages.Ø The storage stability parameters of the LBE additized greases did

not change significantly over a year.Ø Study on tribological evaluation of LBE additized greases and effect

(synergistic or antagonistic) of other performance improvingadditives

LBE (1.4 wt%) with 0.6 % ZDDP resulted in overall best performing candidate

AcknowledgementThe authors are thankful to the management of IOC R&D

for granting permission to present the studyAnd

NLGI-IC for sponsoring the trip

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Thank You

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