Industrial Formulator Training_HLB

Industrial Formulator Training

Rene HaenselGoldschmidt GmbH / Industrial SpecialtiesIndustrial Formulator09.01.2007

2Goldschmidt Industrial Specialties

Emulsion Technology

Introduction- Dispersed Systems- Emulsifier- HLB- Use of co-emulsifier- Paste Method

A good adjusted emulsifier system does not onlystabilize the emulsion, it furthermore providefilm building and wetting properties.


Emulsion Technology

Dispersing Agent Dispersed Substance

Gas Liquid

Solid

Fog

Smoke

Liquid Gas

Liquid

Solid

Foam

Emulsion

Suspension

Solid Gas Solid Foam


Emulsion Technology

During the production of an emulsion two immiscible fluids are mixed, causing a rise in the surface are of the dispersed phase. As this generates an increase of the interfacial tension, the total energy of the system is increased and therefore the stability of the system decreases.


Emulsion Technology


Droplet Formation

W = d A * y

W = Work (required to increase the surface of the dispersed phase,to achieve finely dispersed droplets)

dA= Increase of surface

y = Interfacial tension

The lower the interfacial tension is, the lower is the energy which is needed tocreate new surfaces. A low interfacial tension is necessary to achieve self-emulsifyingproperties and stable finely dispersed emulsions.


Emulsifier

• Emulsifier are surfactants which are amphipathic, containing hydrophobic groups and hydrophilic groups

• Emulsifier adsorb at the interface between oil and water and reducethe interfacial tension

• Emulsifier shall stabilize the interface (the emulsion) by protectingfrom coalescence


Emulsifier


O/W and W/O emulsions


Emulsifier

Nonionic Emulsifier (our product range for Metal Working Fluids)

Anionic Emulsifier

Kationic Emulsifier

Amphoterics


General Rule (W. D. Bancroft, 1913):

• hydrophile (water soluble or dispersable) emulsifiers

=> O/W emulsions

• lipophile (oil soluble) emulsifiers

=> W/O emulsions

General Rule (W. D. Bancroft, 1913):


=> O/W emulsions


=> W/O emulsions

Bancroft, W.D., J. Phys. Cehm. 17, 515,518 (1973).


Hydrophilic Lipophilic Balance

010

20

O

W

HLB

010

20

O W

HLB

010

20

HLB

Emulsifiers with an HLB valueof less than 10 are mainly oil-soluble (lipophilic)---> Emulsifier for W/O-emulsions

Transition point from lipophilicto hydrophilic being situatedapprox. around the HLB value10

Emulsifiers with an HLB valuehigher than 10 are mainly water-soluble (hydrophilic)---> Emulsifier for O/W-emulsions


The HLB System

HLB: Hydrophile Lipophile Balance

PEG-20 Stearate HLB 15

PEG-100 Stearate HLB 19


HLB System according to W. C. Griffin

Result of many years' experimental work (lots of emulsion tests):

HLB Value Use as

1.5 – 3 Antifoaming agent 3 – 8 W/O emulsifier 7 – 9 Wetting agent 8 – 18 O/W emulsifier13 – 15 Wash active substance12 – 18 Solubilizer for aqueous systems

Attention: The system was originally developed for nonionic substances: Fatty acid esters of polyalcohols (glycerin, sorbitol and so on) and their ethoxylates, ethoxylated fatty alcohols and fatty acids

Attention: The system was originally developed for nonionic substances: Fatty acid esters of polyalcohols (glycerin, sorbitol and so on) and their ethoxylates, ethoxylated fatty alcohols and fatty acids


Calculation of the HLB value

1) Fatty acid esters of polyalcohols (also ethoxylated)

SV = Saponification value of the esterAV = Acid value of the fatty acid

HLB = 20 (1 - SV/AV)HLB = 20 (1 - SV/AV)


Calculation of the HLB Value

HLB = E/5HLB = E/5

E = Weight % of the PEG part

2) Ethoxylated fatty alcohols and fatty acids

Attention: The equations are not valid for ionic substances and for nonionicsubstances which contain propylene glycol, butylene glycol, nitrogen, sulfur and so on.

Attention: The equations are not valid for ionic substances and for nonionicsubstances which contain propylene glycol, butylene glycol, nitrogen, sulfur and so on.

Example: PEG-20 = 20 x 44 g/mol = 880 g/molStearic acid = 284 g/molWeight % PEG part = 880/(880 + 284) x 100 = 76 %HLB = 76/5 = 15

PEG-20 Stearate


Calculation of HLB

Example: Determination of the HLB value of an emulsifier mixture

Tagat V 20 HLB 8.4 Tegin OV HLB 3.3

Mixture of Tagat V 20 and Tegin OV with a ratio of 0,83 : 0,17:

HLB = 0.83 x 8.4 + 0.17 x 3.3 = 7.5

Mixture of Tagat V 20 and Tegin OV with a ratio of 0,83 : 0,17:

HLB = 0.83 x 8.4 + 0.17 x 3.3 = 7.5


Estimating the HLB Value of an Emulsifier with thehelp of Solubility Tests in Water (5 %)

HLB Behaviour in Water 1 – 4 Not dispersible in water 4 – 6 Very poor dispersibility 6 – 8 Turbid dispersion after vigorous shaking 8 – 10 Stable turbid dispersion 10 – 13 Opaque to translucent solution> 13 Clear colloidal solution


How to find a suitable emulsifier for metal working fluids

Required HLB´s for O/W – emulsions -Emulsifier should have similar HLB values to that of therespective oils in order to achieve maximum stabilization

Example• Sunfloweroil required HLB approx. 8• Paraffinicoil required HLB approx. 11• Rapeseedoil required HLB approx. 8• Mineraloil required HLB approx. 10-12• Petroleum required HLB approx. 14

- The desired HLB number of the emulsifier can also be achieved bymixing hydrophobic and hydrophilic surfactants


How to emulsify a base oil for metal working fluids

Incorporate the emulsifier/emulsifier blend into the oil phaseExample:

85% Canola Oil + 15% Emulsifier Blend

Blend 1: 15% Tagat V 20, HLB: 8.4; + 85% Canola oilBlend 2: 13% Tagat V 20 + 2% Tegin OV, HLB: 7.7; + 85% Canola OilBlend 3: 11% Tagat V 20 + 4% Tegin OV, HLB: 7,0 + 85% Canola Oil

Incorporate the concentrate in water

- The metal working emulsions are usually diluted between 5 – 10%in water. The concentrate has to be self-emulsifyable. (low shear)


Adjustment of the required HLB value

15% Tagat V 2085% Canola Oil

13% Tagat V 202% Tegin OV

85% Canola Oil


85% Canola Oil


Adjustment of the required HLB value

The optimized HLB leadsnot only to a finely dispersedEmulsion, furthermore thefilm building and wetting properties of an emulsionare improved


85% Canola Oil


85% Canola Oil


Base oil Emulsifier blend HLB Value (calculated)

85 % Rape seed oil 10.5 % TAGAT® V 20 + 4.5 % Oleic acid 45 - 65 % Oleic acid content 12.5 % TAGAT® V 20 + 2.5 % TEGIN® O V ∼ 7.6 10.5 % TAGAT® V 20 + 4.5 % TEGO® SMO V ∼ 7.2 85 % Sunflower oil 10.5 % TAGAT® V 20 + 4.5 % TEGIN® O V ∼ 6.9 ~ % Oleic acid content 90 % Trimethylol propane trioleate 10.0 % TAGAT® V 20 ∼ 8.4 90 % Paraffinic oil (BP) 10.0 % TEGO® STO 85 V ∼ 11.0 C/A: 7 %, C/N: 25 %, C/P: 68 % 90 % Naphthenic oil 10.0 % TAGAT® TO V ∼ 11.3 e. g. Nynas T 22 8.5 % TAGAT® TO V + 1.5 % TEGIN® O V ∼ 10.0 C/A: 10 %, C/N: 43 %, C/P: 47 % 5.0 % TAGAT® TO V + 5.0 % TAGAT® V 20 ∼ 9.9 5.0 % TAGAT® V 20 + 5.0 % FAE + 5 EO ∼ 8.7 55 % Rape seed oil 14.0 % TAGAT® V 20 + 1.0 % Oleic acid 45 - 65 % Oleic acid content 30 % Naphthenic oil 14.0 % TAGAT® V 20 + 1.0 % TEGIN® O V ∼ 8.1 C/A: 11 %, C/N: 45 %, C/P: 44 % 90 % Hydrocrack oil 9.0 % TEGO® STO 85 V + 1.0 % TEGO® STO V ∼ 10.0


Preparing of an emulsion using high energy (e.g. pastemethod)

4.0 % Em ulsifier A

4.0 % Em ulsifier B

40.0 % O ilphase

51.8 % W ater

0.2 % P reservative

- Emulsions which consist of Silicone oil, Silane emulsions, Siliconeresins, OMS as dispersed phase

- Emulsions with high volume ratio of inner phase

Example


Emulsification

Mizer - Blade

Turbine - Stirrer


Emulsification by paste method

0

10

20

30

40

50

60

70

80

90

100

w ater emulsifier A emulsif ier B oilphase preservative

water

Emulsifier A Emulsifier B

Oil phase

Viscosity of mixtureAddition of components

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7

water


Stability of emulsions

Ostwald ripeningCoagulation

Phase inversion

FlocculationCreaming


Stability of emulsions

Coalescence of 2 droplets


Stability of EmulsionsCentrifuge

Quick test to find out if the emulsion tends to separate.

The emulsion is filled in a glastube and treated in a labcentrifuge.If the emulsion is not stable phase separation can be monitored


Vibrating -test

Gives information if the emulsion is sensible to impacts during transport. Due to these impacts coalescence of the emulsion, especiallyon the surface may happen.

Stability of Emulsions


Stability at higher temperature

a) Gives information what happens to the emulsion due to thermal stress during storage or transport.In the summer emulsions can be heated up to 50° C during transport on truck.

b) This test often is made to determine the shelf life within a short time. e.g. 4 weeks at 50°C = 6 month at R.T. (????)

Stability of Emulsions


EmulsionEmulsion: A disperse system consisting of several phases which arises through the mixing of two liquids which are not soluble in each other (e.g. mineral oil and water). One liquid forms the inner or disperse phase, distributed in droplet form in the carrier liquid (the outer or continuous phase). The emulsifyable metalworking fluids are frequently oil – in – water emulsions (O/W), i.e., oil forms the inner phase.During the production of an emulsion two immiscible fluids are mixed, causing a rise in the surface area of the dispersed phase. As this generates an increase of the interfacial tension, the total energy of the system is increased and therefore the stability of the system decreases.

Among the parameters, who determine whether a system made from oil, surfactant and water form an O/W- or a W/O-emulsion, are:• type of surfactant, salt content• type of oil (polarity, viscosity)• volume ratio: oil : waterOils of higher viscosity are more prone to form the coherent phase than oils of lower viscostiyThe tendency of a phase to form the coherent one increases with its volume ratio. Due to geometrical limitations the volume ratio of the coherent phase has to exceed a certain minimum value. This can be derived from the volume demand of the closest sphere packing of the droplets of the dispersed phase.


Emulsion

Emulsifier: An emulsifier also know as surfactant or surface active material is a substance which stabilize interfaces in emulsions. Emulsifier are usually organic compounds that are amphipathic, meaning they contain both hydrophobic groups (their "tails") and hydrophilic groups (their "heads"). Therefore, they are typically sparingly soluble in both organic solvents and water. Emulsifier reduce the surface tension of water by adsorbing at the air-water interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid-liquid interface.

Many surfactants can also assemble in the bulk solution into aggregates that are known as micelles. The concentration at which surfactants begin to form micelles is known as the critical micelle concentration or CMC. When micelles form in water, their tails form a core that is like an oil droplet, and their heads form an outer shell, or corona, that maintains favorable contact with water. When surfactants assemble in oil, the aggregate is referred to as a reverse micelle. In a reverse micelle, the heads are in the core and the tails maintain favorable contact with oil.


Emulsion

How to find the right emulsifier?Emulsifiers should have similar HLB values to that of the respective oils in order to achieve maximum stabilization. Mineral oil has an assigned HLB of 4 when a water-in oil emulsion is desired, and a value of 10,5 when an oil in water emulsion is to be prepared. Accordingly, the HLB number of the emulsifier should also be around 4 and 10,5, respectively. The desired HLB numbers can also be achieved by mixing lipophilic and hydrophilic surfactants. (see HLB)Example: Determination of the HLB value of an emulsifier mixtureEmulsifier A: HLB 3.8Emulsifier B: HLB 16.4

Mixture of A and B with a ratio of 40 : 60:HLB = 0.4 x 3.8 + 0.6 x 16.4 = 11.36


Emulsion

• The "required HLB value“ can only be a guideline,as the result of emulsification fundamentally depends on:

• Amount of emulsifier• Phase weight ratio of the emulsion• Electrolyte content of water• Emulsification temperature• Emulsification method

• For the choice of the emulsifier not only its correct HLB value is important, but also the choice of the suitable chemistry.

• An experimental determination of the HLB value only makessense with standards whose HLB values are correct.


Emulsion

HLB: HLB stands for hydrophilic – lipophilic – balance. Surfactants with a low HLB are more lipid loving and thus tend to make a water in oil emulsion while those with a high HLB are more hydrophilic and tend to make an oil in water emulsion. General Rule (W. D. Bancroft, 1913):


=> O/W emulsions


=> W/O emulsions

Attention: The system was originally developed for nonionic substances: Fatty acid esters of polyalcohols (glycerin, sorbitol and so on) and their ethoxylates, ethoxylatedfatty alcohols and fatty acids.


Emulsion

Ethoxylated fatty alcohols and fatty acidsHLB = E/5E = Weight % of the PEG part

Example: PEG-20 Stearate

PEG-20 = 20 x 44 g/mol = 880 g/molStearic acid = 284 g/molWeight % PEG part = 880/(880 + 284) x 100 = 76 %HLB = 76/5 = 15

Attention: The equations are not valid for ionic substances and for nonionic substances which contain propylene glycol, butylene glycol, nitrogen, sulfur and so on.

Industrial Formulator Training_HLB

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