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 noEmulsifier 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 emulsifiersoluble oil formulation

NIO: alcohol ethoxylate





What are ethercarboxylic acids?

RO

OOM

O

n

RO

OOM

O

n

RO

OOM

O

n





Ethercarboxylic acids in metalworking

long chain EC short chain EC

RO

OCH

2COOM

n





Ethercarboxylic acids - synthesis

OH

O

NaOHR

OO

Hn

1.) Ethoxylation of fatty alcohol

2.) Carboxymethylation

RO

OH

n

NaOHClOH

OR

OO

ONa

O

n

-H2O+ +

mechanism: Williamson ethersynthesis

RO

OONa

O

n

H+

RO

OOH

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?

RO

OO

m

n

OM

O

RO

OO

Hm

n

Nonionic emulsifierfatty alcohol alcoxylate

anionic emulsifierEthercarboxylate





(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 ?

RO

OO

m

n

OM

O

RO

OO

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

RO

OO

m

n

OM

O

RO

OO

Hm

n





Thank youfor

your kind attention !

Any questions?

Acknowledgements

KCG R&D team

Robert Stubbs

Science

New tool box for superior foam control in metalworking fluids