New tool box for superior foam control in metalworking fluids

Dr. Michael Stapels; Kao Chemicals GmbH
69th STLE Annual Meeting & Exhibition – Lake Buena Vista, Florida USA – May 18 – 22, 2014
New tool box for superior foam
control in metalworking fluids
Dr. Michael Stapels
Kao Chemicals GmbH, Emmerich, Germany

contents
• modern metalworking fluids
• price-performance of metalworking additives
• chemistry & performance of Ethercarboxylic
acids ?
• simple replacement of emulsifier chemistry?
• alternative raw material for emulsifiers in
metalworking fluids

Different fluid types
Metalworking
fluid
Straight oil Soluble oil Synthetic fluidSemisynthetic fluid
Mineral oil > 90%
Emulsifier no
Mineral oil 50-90%
Emulsifier yes
Mineral oil 5 - 40%
Emulsifier yes*
* relatively high amount
Mineral oil no
Emulsifier no
real solution

Different emulsifier concepts
Concentrate
stability
Emulsion
stability
Cost
efficency
Hard water
tolerance
Corrosion
control
Foam
control
…
concept A
concept B
concept C
concept D
….
most probably there is no all-in-one fluid

Different emulsifier concepts
most probably there is no all-in-one fluid

water hardness
Water hardness affects cutting fluid balance.
Different geographic regions have different
degrees of waterhardness. Compensating
for water hardness will optimize fluid
performance.
keep an eye on: Evaporation losses !
balancing losses concentration of ions with time

Machining magnesium alloys

Understanding emulsion failure

-
-
-
-
-
-
-
- Ca2+
Ca2+
Ca2+
-
-
-
-
Emulsion failure by cation loading

-
-
-
-
-
-
-
-
Ca2+
Ca2+
Ca2+
-
-
-
-
Ca2+
Ca2+
Ca2+

-
-
-
-
-
-
Ca2+
Ca2+
Ca2+
-
-

Stabilizing effect of emulsifier
soluble oil formulation
NIO: alcohol ethoxylate

What are ethercarboxylic acids?
R
O
O
OM
O
n
R
O
O
OM
O
n
R
O
O
OM
O
n

Ethercarboxylic acids in metalworking
long chain EC short chain EC
R
O
O
CH2COOM
n

Ethercarboxylic acids - synthesis
OH
O
NaOH
R
O
O
H
n
1.) Ethoxylation of fatty alcohol
2.) Carboxymethylation
R
O
O
H
n NaOHCl
OH
O
R
O
O
ONa
O
n-H2
O+ +
mechanism: Williamson ethersynthesis
R
O
O
ONa
O
n
H
+
R
O
O
OH
O
n
Nonionic emulsifier
fatty alcohol ethoxylate
Anionic emulsifier
Ethercarboxylic acid

Emulsifier replacement - foaming
A B A B
Naphthenic base oil (T22) 57,0 57,0
TMP Trioleate 8,0 8,0
50% KOH 3,5 3,5
Polyglycol ether 2 EO * 9
DTO 25/30 5,0 5,0
nat. Sulphonate MW 450 13,5
Polyoxyethylene(9) ether carboxylic acid ** 4,5
Hexylene Glycol 6,5 6,5
2-butyl octanol 1,5 1,5
monocyclic C21 dicarboxylic acid 3,0 3,0
*based on oleyl / cetyl alcohol
**based on oleyl alcohol (80/85)
typical high oil coolant formulation appearance 10% dilution 2500 ppm as MgCl2

Emulsifier replacement - stabilizing

A B A B
Naphthenic base oil (T22) 57,0 57,0
TMP Trioleate 8,0 8,0
50% KOH 3,5 3,5
Polyglycol ether 2 EO * 9
DTO 25/30 5,0 5,0
nat. Sulphonate MW 450 13,5
Polyoxyethylene(9) ether carboxylic acid ** 4,5
Hexylene Glycol 6,5 6,5
2-butyl octanol 1,5 1,5
monocyclic C21 dicarboxylic acid 3,0 3,0
*based on oleyl / cetyl alcohol
**based on oleyl alcohol (80/85)
shaking cylinder (foam stability after 30 s)
typical high oil coolant formulation 5% dilution (100 ppm CaCO3/l)

Optimizing performance
Optimization
- Minimize foam for different water
hardness
- Maximise hard water tolerance
coco fatty acid
oleic acid
talloil fatty acid
erucic acid
…
oleyl – 2EO
oleyl – 5EO
oleyl – 9EO
…

Propoxylation technology
• Propoxylation technology
established in industrial /
institutional cleaning
• provide a balance of low foam
and good detergency

PO EO emulsifier for metalworking
What about nonionic anionic emulsifier interaction?
R
O
O
O
m n OM
O
R
O
O
O
Hm n
Nonionic emulsifier
fatty alcohol alcoxylate
anionic emulsifier
Ethercarboxylate

(main) function component % by weight
lubrication mineral oil 45 - 50
lubrication ester 5 - 15
pH reserve / corrosion control amines 5 - 10
boundary lubrication / foam control fatty acid 5-10
corrosion control fatty acid amides 3 - 5
EP lubricant sulphur carrier 5
emulsifier alcohol ethoxylate 3
co-emulsifier / stabilizer alkyl ether carboxylic acid 2
biocide isothiazolinones max. 2
water ad 100%
typical high oil formulation

(main) function component % by weight
lubrication mineral oil 45 - 50
lubrication ester 5 - 15
pH reserve / corrosion control amines 5 - 10
boundary lubrication / foam control fatty acid 5-10
corrosion control fatty acid amides 3 - 5
EP lubricant sulphur carrier 5
emulsifier alcohol ethoxylate 3
co-emulsifier / stabilizer alkyl ether carboxylic acid 2
biocide isothiazolinones max. 2
water ad 100%
typical high oil formulation
commercial blackbox
commercial blackbox

typical high oil formulation – emulsifier package

emulsion aspect (5% - 100 ppm)
emulsifier for micro-emulsions

PO EO emulsifier - package
What about foam control ?
R
O
O
O
m n OM
O
R
O
O
O
Hm n

Problems due to foaming
Unwelcome consequences of foaming
- reducing fluid‘s lubricity
- obstructing skimming of tramp oil
- handicapping chip management
- Heating up of the fluid
- part quality issues
- speed up corrosion processes
- fluid evaporation
- safety issues
- bubbles onto the shop floor cause slip hazards
becomes more important due to new trends in machining / processing
(high pressure cooling)

Laboratory evaluation of foaming

Laboratory evaluation of foaming
low foaming ether carboxylic acid (1% aq.)

Formulation 1 Formulation 2 Formulation 3 Formulation 4
NIO: oleyl oleyl POEO POEO
EC: oleyl POEO oleyl POEO
5% emulsion (100 ppm)
Foaming properties of different emulsifier combinations
start

end foaming

15s collapse

30s collapse

foaming
max foam [mm] 5 mm reduction 20 mm reduction
formulation 1 98,3 4,8 > 30
formulation 2 29 1,2 4,4
formulation 3 75,8 1,2 5,8
formulation 4 65,3 1 3,6
foam collapse

Residue control of different emulsifier combinations

conclusion
nonionic (3%) anionic (2%) foam control residue control

PO EO emulsifier as toolbox
R
O
O
O
m n OM
O
R
O
O
O
Hm n

Thank you
for
your kind attention !
Any questions?
Acknowledgements
KCG R&D team
Robert Stubbs

New tool box for superior foam control in metalworking fluids

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