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Modified Fatty Acids as Alternative Soap Thickeners for Lubricating Greases
Presentation to NLGI 2021 Annual Meeting
Devin Granger & Shadaab Maghrabi
09/30/2021
Renewable raw materials
Tall oil rosin
Tall oil fatty acid
Lignin
▪Pavement
▪Lubricants
▪Oilfield
▪Biodiesel (1)
▪Adhesives
▪Paper size
▪Rubber
▪Inks
▪Sterols
▪Renewable energy
▪Mining
▪Ag chem
▪Pavement
▪Batteries
▪Dyes
Biorefinery
Derivative end-uses
Biofractions
Pulp Mill
2
Intermediate products
We Add Value Throughout the Pine Chemicals Chain
▪ CTO contracts in place to cover ~90% of 2022 demand; 65% covered by long-term supply agreements
▪ Anticipated cost inflation over the next 4-5 years
Crude tall oil
1| Early stages of market exploration and/or participation
Agenda
Project
Development
Methodology
Testing
Results
Conclusions
Alternatives to 12-Hydroxystearic Acid
Why alternatives to 12-HSA?
12-Hydroxystearic acid for the grease industry is primarily produced in 1 region
COVID-19 Pandemic highlighted potential for disruption [1] from:
• Raw material shortages
• Port closures
• Supply chain disruptions
Challenges
• 12-HSA is a high performing material with decades of data and usage
• Stearic acid, chemically modified stearic acid and other isomers of hydroxystearicacid underperform compared to 12-HSA [2]
• More recent fatty acid derivatives show some promise as alternative materials, but mostly targeted at modifying 12-HSA thickener structures [3]
[1] https://www.ilma.org/ILMA/ILMA/ILMA-News/2020/Castor_oil_derivatives.aspx[2] Mould, W.R.; Silver, H.B. “An Investigation of the Thickening Properties of Substituted Lithium Stearates in Liquid Paraffin Base Oil” NLGI Spokesman, April 1976, 22.[3] Bertin, P.A.; Bessette, P.A. “Biorefinery-Derived Long Chain Dibasic Complexing Agents for Lithium Thickened Lubricating Greases” NLGI Spokesman, 79 (5), 2015, 24.
Methodology
Raw Material Selection
Sample Preparation
Sample Evaluation
Base Oil
Thickener
Counterion
Formulate
Cook
Mill
Dilute
Standard Testing
Sample Preparation
Base Oil - Initial 55.39% 304.27
12-Hydroxystearic acid 14.75% 81.00
LiOH Monohydrate 2.16% 11.88
DI Water 23.76
Base Oil - Let Down 27.70% 152.14
Base Oil - Finishing - As Needed
Typical Charge 100% 549.29
Treat Mass (g)Component Treat Rate (%)
Formulate Cook Mill
Dilute
Sample Evaluation
DIN 51810-2Rheology of Greases
Lg M
od
ulu
s (
Pa)
Lg Shear Stress (Pa)
τy τf
G’
G”
LVE Range
ASTM D217Worked Penetration
ASTM D1831Roll Stability & ASTM D1403 ¼ Scale Penetration
ASTM D6184Oil Separation
ASTM D566Dropping Point
Naphthenic Base Oil 1 (NBO1) – ISO VG 22
MFA: Modified fatty acids
12-HSA: 12-Hydroxystearic acid
12-HSA 12-HSA/AA MFA1 MFA2
191
12 253 2.5
MFA2 16 246 3 0.2
Oil Bleed (%)
2.5 0.7
MFA1 13 245 3 0.2
0.2
12-HSA +
Azelaic Acid13 (11 + 2) 251
Dropping Point
(°C)
196
224
184
ThickenerThickener
Conc. (%)
Pentration
(0.1 mm)NLGI Grade
12-HSA
Shear Stability of NBO1 Greases
Naphthenic Base Oil 2 (NBO2) – ISO VG 220
12-HSA 12-HSA/AA MFA1 MFA2
MFA: Modified fatty acids
12-HSA: 12-Hydroxystearic acid
NLGI GradeDropping Point
(°C)
MFA2 12 284 2 182 0.3
MFA1 8 249 2.5 183 0.0
12-HSA +
Azelaic Acid8 (7 + 1) 241 3 223 0.7
Oil Bleed (%)
12-HSA 7 239 3 198 0.1
ThickenerThickener
Conc. (%)
Pentration
(0.1 mm)
Shear Stability of NBO2 Greases
Group I & II Base Oils
12-HSA 12-HSA/AA MFA1
Group II – ISO VG 22
12-HSA MFA1
Group I – ISO VG 22
12-HSA +
Azelaic Acid12 (10 +2) 255 2.5 220 3.4
MFA1 13 298 1.5 177 0.7
ThickenerThickener
Conc. (%)
Pentration
(0.1 mm)NLGI Grade
Dropping Point
(°C)Oil Bleed (%)
12-HSA 12 273 2 201 1.1
MFA1 16 332 1 183 2.2
ThickenerThickener
Conc. (%)
Pentration
(0.1 mm)NLGI Grade
Dropping Point
(°C)Oil Bleed (%)
12-HSA 12 273 2 205 1.3
Diacid Grease – VP100 Base Oil (paraffinic group I)
Group I Group II Group I Group II
Rheology by DIN 51810-2 Method A (Strain) for NBO1
Method:• Load sample• Heat to 40°C
• Rate = 0.4 °C/min• Hold at test temp
for 30 min• Strain sweep
• 0.01 – 100%• Angular frequency
(ω) = 10 1/s
G’ = Storage modulus❖ Solid component of VES❖ Related to film
strength/penetrationτy = yield point❖ Force needed to soften
the VESτf = yield point❖ Force needed to liquify
the VES
G' τy τf
12-HSA 5.20E+04 188 1210
12-HSA/AA 8.10E+04 183 1480
MFA1 4.50E+04 325 1020
MFA2 5.10E+04 230 936
Thixotropy of NBO1 Lithium Greases
Method:• Temperature equilibrated as in
DIN 51810-2• Strain set within the LVE (0.1%),
and baseline measured• Strain set above τf (100%), and
response measured• Strain set within the LVE (0.1%),
and modulus recovery observed
Gives a sense of physical state changes during deformation and relaxation
Summary
• Appearance and texture of all MFA greases are like Lithium 12-hydroxystearate and
Li 12-HSA/Azelaic acid greases
• Smooth, semi-transparent, easily spread with a pallet knife, sticks to surfaces
• Physical properties of MFA greases are base oil dependent
• Shear stability
• Water resistance
• Dropping points
• Oil separation
• Rheology of MFAs is comparable to Li 12-HSA and Li 12-HSA/AA
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