New Generation of Phosphate-Esters for MWF: Balancing Per- Formance, Labeling and Economics

New generation of phosphate-esters for MWF: balancing performance, labeling and economics.

Claude-Emmanuel Hédoire 1),

1) Solvay Novecare, Aubervilliers, France

1 Introduction

Phosphate-esters are well known multi- functional additives for metalworking fluids. They are emulsifiers for expandable oils, as well as anti-wear additives, corrosion and staining inhibitors. The most currently used phosphate-esters are based on long carbon chains, like cetyl oleyl chain. While providing excellent emulsion stability, good anti- wear performance and good staining inhibition, they tend to foam too much and to generate soap in hard water, creating deposits on tools, work-pieces or filters. Besides, their eco-toxicity has been reviewed in 2015 and they are now classified as very toxic to aquatic life. They are no longer a good optimum between performance, regulation and economics and this paper intro- duces a new generation of phosphate-esters

2. Summary

Solvay researchers took a number of steps to optimize the performance, classification of phosphate- esters. The first one was the switch to a shorter chain alcohol. This provides a better classification, an enhanced soap formation control and a better security of supply. The second one was propylene oxide insertion into the molecule. This provides similar performance to cetyl oleyl alcohol ethoxylates in terms of emulsion stability as well as anti-wear performance, and enhanced performance in terms of foam control. The result is the development of a new generation of phosphate-esters that optimize performance and economics, and allow milder labeling.

New generation of phosphate- esters for MWF: balancing performance, regulation and economics v1 STLE annual meeting,Las Vegas, May 2016

Claude-Emmanuel Hédoire Agenda

• Common emulsifiers for MWF

• Current generation of phosphate-esters: pros and cons Phosphate-esters based on cetyl oleyl alcohol are no longer an optimum between performance, classification and economics

• Molecular design of phosphate-esters • Some chemistry • State of the art: what are the tools to improve performance, classification and economics There is no ideal phosphate-ester on the market

• Development of a new generation of phosphate-ester New optimum between performance, classification and economics

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Common Emulsifier types in MWF

• Anionics and non-ionics are used in MWF formulations • Besides emulsion stability, emulsifiers can provide MWF with other side- benefits • Emulsifier systems are elaborated blends of components to finely balance their benefits and their limitations

Low Corrosion / Lubricity Anti-wear Stability in foam staining HW protection Anionics Amine soaps of fatty acids

Synthetic and natural sulfonates

Amine soaps of phosphate-esters

Amine soaps of ether-carboxylates

Non-ionics Ethoxylated fatty alcohols

Ethoxylated fatty acids

Ethoxylated amines and amides Common Emulsifier types in MWF

Low Corrosion / Lubricity Anti-wear Stability in foam staining HW protection Anionics Amine soaps of fatty acids

STLESynthetic 2016 and natural sulfonates

Amine soaps of phosphate-esters

Amine soaps of ether-carboxylates

Non-ionics Ethoxylated fatty alcohols

Ethoxylated fatty acids

Ethoxylated amines and amides

Phosphate -esters: pros and cons of current generation (1)

The current generation is based on phosphate-ester of (cetyl oleyl + 5 EO)

Cetyl oleyl: C16 -C18:1

Performance: emulsion Performance: hard water stability

solution

Heavy Clear soap formation

• Good emulsion stability

• Low foam in DI water, ultra low-foam in • Heavy soap formation in HW HW due to soap formation • Soap formation is positive for foam control,

• No defoaming in DI water, excellent but soap precipitates on tools, workpieces, defoaming in hard water due to soap filters … formation 5

Phosphate -esters: pros and cons of current generation (2)

The current generation is based on phosphate-ester of (cetyl oleyl + 5 EO)

Cetyl oleyl: C16 -C18:1

Performance: side benefits Regulation

• Good corrosion / staining inhibition • Classification blank • H315: Causes skin irritation

• H318: Causes serious eye damage

1% PE • H410: Very toxic to aquatic life with long-lasting effects

• Good AW performance • Labels

Pros and cons of current generation: conclusion

Cetyl oleyl phosphate-ester

Emulsion stability Cetyl oleyl: C16-C18:1 Good Low foaming DI water: good, Hard water: good through soap formation Defoaming DI water: good, Hard water: good through soap formation Performance Hard water stability Poor Staining inhibition Good AW performance Good

Toxicity H315, H318 Classification and labeling Eco-toxicity H410

Commercial Raw material availability Supply of cetyl oleyl alcohol is very tight

• Phosphate-esters based on cetyl oleyl alcohol are no longer an optimum between performance, classification and economics A new optimum has to be found

7 Agenda

• Common emulsifiers for MWF

• Current generation of phosphate-esters: pros and cons Phosphate-esters based on cetyl oleyl alcohol are no longer an optimum between performance, classification and economics

• Development of a new generation of phosphate-ester New optimum between performance, classification and economics

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Some chemistry …

• The phosphation process leads to a mixture of several substances:

Mono-ester: 50 – 60%

Di-ester: 30 – 45%

Residual non-ionic 3 – 10%

When considering performance and classification, it is necessary to take into account noth the phosphate-esters and the residual non-ionic

9 Molecular design: state of the art

CH 3 -

R (CH(CH2 -CH2 -O)O)n (CH(CH 2 - CH 2 - O)O) m OH

CH 3 - OH

R (CH(CH - CH - O)O) (CH(CH - CH - O)O) 2 2 n 2 2 m O P O

Fatty alcohol Ethylene oxide Propylene oxide (ROH) (EO) (PO) OH

• More favorable classification and • More favorable classification and labelling for short carbon chain vs long labelling for Regulation higher EO and PO carbon chain (CESIO guidelines) degrees (CESIO guidelines)

• Cetyl oleyl alcohol supply is very tight

• Other carbon feedstocks are more Commercial

available

• Higher EO degree increases foam • Higher AW performance with longer chain • PO insertion enables a better foam control … the challenge is to Performance • Better soap formation control with maintaing good emulsification shorter chain performance

Classification of short chain phosphate-esters is more favorable

CESIO guidelines for environmental classification. CESIO is European Committee of Organic Surfactants and Intermediates. Most of the surfactant manufacturers belong to CESIO

Chemical name Carbon EO Hazard Hazard phrase Label chain degrees statement (classification) length (classification)

C8 – C10 3 - 20 NC None _

12 3 - 20 NC None _

iC13 H400 Very toxic to aquatic life 3 H411 Toxic to aquatic life with long lasting effects 5 - 20 H412 Harmful to aquatic life with long lasting effects _ 13 3 - 20 H412 Harmful to aquatic life with long lasting effects _ 12 - 14 3 – 20 NC 12 - 15 3 – 20 NC 12 - 18 3 - 20 NC H400 Very toxic to aquatic life 18 : 1 5 – 6 H412 Harmful to aquatic life with long lasting effects 18 : 1 12 - 20 NC

11 0/0/13 Classification of short alcohol ethoxylates is more favorable CESIO guidelines for environmental classification. CESIO is European Committee of Organic Surfactants and Intermediates. Most of the surfactant manufacturers belong to CESIO Environmental classification of surfactant according to 2nd ATP, public revision 2015

Chemical name Carbon EO Hazard Hazard phrase Label chain degrees statement (classification) length (classification) Alcohols, C8, 8 All NC None _ ethoxylated Acohols, C10, 10 All NC None _ ethoxylated Alcohols, C12-C16, 12 - 16 H400 Very toxic to aquatic life < 5 ethoxylated H412 Harmful to aquatic life with long lasting effect 5 – 15 H412 Harmful to aquatic life with long lasting effects _ > 15 NC None _ Alcohols, C14, 14 H400 Very toxic to aquatic life < 6 ethoxylated H412 Harmful to aquatic life with long lasting effects 6 - 15 H412 Harmful to aquatic life with long lasting effects _ > 15 NC None _

Alcohols, C16-C18, 16 - 18 < 5 H411 Toxic to aquatic life with long lasting effects ethoxylated H400 Very toxic to aquatic life 5 – 10 Saturated and H412 Harmful to aquatic life with long lasting effects unsaturated 10 - 20 H412 Harmful to aquatic life with long lasting effects > 20 EO NC None _ 12 0/0/13 State of the art: short chain phosphate-ester vs cetyl oleyl phosphate-ester

Short chain Cetyl oleyl phosphate-ester phosphate-ester

Classification Eco-toxicity

Commercial Raw material availability

Emulsion stability

Low foaming

Performance Defoaming

Hard water stability

AW performance

Commercial: availability depends on the

feedstock type and manufacturing

Branched alcohols Lauryl alcohol

• Synthetically manufactured • Manufactured from palm from crude oil kernel oil and synthetically from crude oil • Base feedstock for numerous

types of surfactants (coatings) • Commonly and widely available:

• > 10 suppliers in Asia • > 5 suppliers in Europe Cetyl oleyl alcohol • Approx. 5 suppliers in North America • Manufactured from palm kernel oil, with a patented • Base feedstock for numerous technology types of surfactants (home and personal care) • Only 3 suppliers in the world, with production sites in Asia and Europe

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State of the art: short chain phosphate-ester vs cetyl oleyl phosphate-ester

Short chain Cetyl oleyl phosphate-ester phosphate-ester

Classification Eco-toxicity

Commercial Raw material availability

Emulsion stability

Low foaming

Performance Defoaming

Hard water stability

AW performance

15 Performance: state of the art

Performance: AW Performance: hard water stability

• Higher AW performance with cetyl oleyl • Heavy soap formation with cetyl oleyl phosphate-ester phosphate-ester • Lower soap formation with short chain phosphate-ester

Performance: state of the art

Good emulsion stability with cetyl oleyl phosphate-ester and with short chain phosphate-ester

Low foam in DI water with cetyl oleyl phosphate-ester and with short chain phosphate-ester Low foam in Hard water with short chain phosphate-ester. Lower foam with cetyl oleyl phosphate-ester, due to soap formation

Better defoaming in DI water with short chain phosphate-ester

State of the art: short chain phosphate-ester vs cetyl oleyl phosphate-ester

Short chain Cetyl oleyl phosphate-ester phosphate-ester

Classification Eco-toxicity

Commercial Raw material availability

Emulsion stability

Low foaming

Performance Defoaming

Hard water stability

AW performance

• There is no ideal phosphate-ester for MWF on the market

18 Agenda

• Common emulsifiers for MWF

• Current generation of phosphate-esters: pros and cons Phosphate-esters based on cetyl oleyl alcohol are no longer an optimum between performance, classification and economics

• Development of a new generation of phosphate-ester New optimum between performance, classification and economics

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Development of a new generation of phosphate-

ester CH 3 -

R (CH(CH2 -CH2 -O)O)n (CH(CH 2 - CH 2 - O)O) m OH

CH 3 - OH R (CH(CH - CH - O)O) (CH(CH - CH - O)O) 2 2 n 2 2 m O P O Fatty alcohol Ethylene oxide Propylene oxide (ROH) (EO) (PO) OH

More favorable classification and Eco-toxicity: Must be a short chain labelling for higher EO and PO degrees Regulation (CESIO guidelines)

Raw material availability: Must be a Commercial short chain

EO and PO distribution fine-tuning in

S oap formation control: must be a order to improve the AW performance. Performance short chain The challenge is not to loose the emulsion performance

Best candidate; Improved Overall Performance

Naphthenic oil • Stable emulsions, with paraffinic and naphthenic oil based formulations, in soft and hard water

• Low foaming, without soap formation

• Outstanding defoaming, especially for DI water emulsions

• Water hardness: 400 ppm • Emulsion stability: 7d @ 40 °C • Foam test: CNOMO

21 Best candidate: good AW performance

• Nytex 810 with 2% of additive • Falex Pin and Vee blocks, ASTM D2670 (700 lbs, 10 min)

Higher AW performance

22 0/0/13 Best candidate: limited soap formation

Limited soap formation

Water hardness: 400 ppm solution solution

Clear Clear

Heavy soap formation

23 0/0/13 Best candidate: good aluminum staining inhibition

• Water hardness: 0 ppm • 28d @ 40 °C

Weight uptake Al 2024 Al 6061 Al 7075 (mg) No additive 30,6 34,8 30,5

Best candidate 0,1 0,1 0,1 (1%) Cetyl oleyl phosphate-ester 0,3 0,2 0,1 (1%) 24 0/0/13 Best candidate versus Cetyl Oleyl phosphate-ester

Cetyl oleyl Best candidate phosphate-ester Emulsion stability Good Good

Low foaming Good Good

Defoaming Excellent Good Performance Hard water stability Good Poor

Staining inhibition Good Good

AW performance Good Good

Toxicity H315, H318 H315, H318

Classification Eco-toxicity Not classified H400, H412

Globally available raw Supply of cetyl oleyl Commercial Raw material availability material alcohol is very tight 25 Please come and visit us at booth #

www.solvay.com Common Emulsifier types in MWF

Low Corrosion / Lubricity Anti-wear Stability in foam staining HW protection Anionics Amine soaps of fatty acids

STLESynthetic 2016 and natural sulfonates

Amine soaps of phosphate-esters

STLEAmine 2015 soaps of ether-carboxylates Non-ionics Ethoxylated fatty alcohols

Ethoxylated fatty acids

Ethoxylated amines and amides

STLE 2015: introduction of new non-ionic emulsifiers

Sustainability benefits

• Low eco-toxicity (no dead fish label) • Readily biodegradable • Based on commonly and globally available raw materials

Performance benefits • Low foam to ultra-low foam • Outstanding defoaming • Excellent low temperature stability

Cetyl oleyl Short chain alcohol Short chain alcohol Short chain alcohol 5 EO Low EO/PO degree Medium EO/PO degree High EO/PO degree Emulsion stability Low foam Defoaming

28 Labels 0/0/13

Emulsifiers for MWF

• Emulsifiers are backbone additives for water soluble MWF:

soluble oils and semi-synthetic fluids

• They stabilize the oil in water emulsions

• The oil droplet size distribution is a result of the choice of emulsifiers

• Some of them bring valuable side benefits

• With corrosion inhibitors, emulsifiers are the type of additives the most used in MWF

• They represent 140 kT/y out of a global additive consumption of 600 kT/y

Additives for MWF (WW), 600 kT

WW MWF market (million MT) Antiwear 3% Others 12% Buffer Corrosion inhibitors CAGR = 2,3 %/y 6% 24%

2,5 Extreme pressure Emulsifiers 13% 23% 2,2 10 - 40% additives Friction 60 - 90% base oil modifiers 19%

2012 2017 (Kline)

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Trends in MWF and challenges for emulsifiers

Trends in MWF Challenges for emulsifiers

• New generation of high speed • Development of a new generation of emulsifiers with ultra low foam and Performance machine tools require much improved foam control enhanced defoaming, without defoamer addition and without soap formation

• GHS in place for substances and • Change in classification and labelling for

formulations some emulsifiers

Regulation • Development of a new generation of • More and more stringent emulsifiers with millder labelling

regulations for biocides (boric acid, formaldehyde releasers …) • Development of biostable emulsifiers

• Cost-effectiveness of RM and • New generations of emulsifiers should be

Commercial MWF based on commonly and globally available raw materials • WW availability of RM

• A lot of challenges faced by MWF formulators and emulsifiers suppliers !

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Emulsifiers; Performance Evaluation

Concentrate

• Oil 80% solubility

Emulsifier 20% stability •

Emulsion

Oil

Cream Short term stability: 30 min • Concentrate 10% Long term stability: 40 °C, 7 days • DI water 90% Emulsion or hard water (400 ppm) Foaming: recycling test (CNOMO), NF T 60 185 • MEA pH=9 Droplet size Water

The CNOMO Foam Test

• The CNOMO foam test D655212 describes a fluid circulation test using a centrifugal pump and a water- jacketed 2000 mL graduated cylinder with an outlet on the side, near the bottom

• A formulation is added to the cylinder to the 1000 mL level. It is then pumped from the bottom of the cylinder at a rate of 250 L/h and cascaded backed upon itself from a height of 390 mm above the 1000 mL mark.

• The test is run for a maximum of 5h or until the foam level reaches the 2000 mL mark. The pump is then stopped.

• Collected data are: • Volume of foam above the 1000 mL mark immediately after the pump is stopped (5h). • Time to reach the 2000 mL mark (if reached) • Volume of foam above the 1000 mL mark 15 minutes after the pump is stopped

• This test simulates fluid flow in a machine sump or central system, but is much more severe due to the extremely high turnover rate

MWF: CNOMO Foam Test

Low foam MWF Ultra Low foam MWF • High amount of foam is generated • Low amount of foam is generated: the rapidely: 1000 mL within 2 to 15 test can be run for 5 hours without minutes reaching 1000 mL of faom

• The pump is then stopped for • The pump is then stopped for

defoaming evaluation defoaming evaluation

Low foam

Ultra Low foam Spiders; An overall Evaluation of Performance

Higher Emulsion stability

Lower foam Improved defoaming

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Results ; An overall Evaluation of Performance

• Emulsion stability index • 100 – 5 × volume of oil phase – 5 × volume of water phase – 1 × volume of cream

• Foam profile indexes • Initial foam level index: 100 − 10 × (1 + log ) • Defoaming index: 100 x

Emulsion stability Short term DI Water 100

Defoaming 80 Emulsion stability Short term Hard water Hard Water 60

40 Higher 20 Emulsion stability Defoaming Emulsion stability Long term 0 DI water DI Water Lower initial foam level and better defoamning Initial foam level Emulsion stability Long term Hard water Hard Water 35 0/0/13 Initial foam level DI water