Additives for Pesticide Formulations

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When our flagship product BREAK-THRU® S 240 was introduced in 1992, our focus was on tank-mix adjuvants. Since then, we have started to include different surfactant classes into pesticide our portfolio. Drawing upon our in-house pool of surfactants and the in-depth knowledge of interfacial processes and technologies, we have expanded our product portfolio to include additional organomodified siloxanes and other specialty surfactants. BREAK-THRU® is a regis-tered trademark of Evonik Industries AG.

About UsEvonik Industries is the creative industrial group from Germany which operates in three business areas: Chemicals, Energy and Real Estate. Evonik is a global leader in specialty chemicals, an expert in power generation from hard coal and renewable energies, and one of the largest private residential real estate companies in Ger-many. Our strengths are creativity, spe-cialization, continuous self-renewal, and reliability. Evonik is active in over 100 countries around the world.

The Business Line Interface & Performance of Evonik Industries AG has its base in all kinds of organic specialty surfactants and or-ganomodified siloxanes. We hold strong po-sitions with antifoams, emulsifiers, corrosion inhibitors, dispersing aids, hydrophobing and wetting agents, softeners and radiation curable release coatings. Our broad product range, technological background and appli-cation know-how addresses several indus-tries like plastics, rubber, label, tape and re-lease liner manufacturing, construction, lubricants, agro, textile and tissue industry.

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In the middle of this decade, we started to develop prototype formulations to pro-vide guidance to the user with respect to product and functionality. For us the aim is to give you the ability to differentiate your formulation in the market place by offering superior agrochemical products. The effects of our products are not limited to enhancing and safeguarding biological efficacy. We also offer unique antifoams with superior compatibility allowing crys-tal clear formulations or novel additive systems such as our patented thermody-

namically stable microemulsions. With a decreasing number of new actives specifi-cally in the crop protection area, and a growing generic market, it is our goal to provide solutions to meeting the competi-tive demands of the pesticide industry.

Our formulation experts combine decades of experience from the agricultural chem-ical and other industries and have merged their knowledge with that of our plant physiologists who link it to performance in the field. In this way, we offer a novel

package of products and expertise. Vari-ous examples of guideline formulations are given in the end of this document.

While this brochure is designed to give an overview of our current agro activities, we are continuing to add new products and develop new guideline formulations. Contact your representative for the latestinformation.

Our Product RangeOil EnhancersInfluence surface tension and spreading of oil

Wetting Agents• Trisiloxanes• pH stable polysiloxanesEnhance deposition of pesticides by lowering surface tension of spray water and improving spread

AntifoamsSuppress or eliminate foam during manufacturing, packaging and tank-mixing

Dispersing AgentsImprove the dispersion and suspension of solid particles

EmulsifiersEffectively emulsify oils in water

Rheology ModifiersStabilize active ingredients in liquid formulations and adjust to the viscosity

Carrier Substances and Flow AgentsAre highly efficient for absorption of liquid components and improving the free flow, anti-caking and milling behaviour

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Oil EnhancersMany pesticides exhibit limited water solubility, so mineral and vegetable oils often serve as the carriers to deliver these actives to plants or pests. When incorporated into oil-containing for-mulations such as EC’s, EW’s or OD’s, the BREAK-THRU® OE series of organomodified poly-siloxanes lowers the bulk surface tension of the oils which leads to improved spreading and dis-tribution of the oil droplets onto and into the target. With the improved performance of these oil-based pesticide formulations, it is possible to increase pesticide performance and reduce the amount of spray oil, thereby reducing cost, phytotoxicity risk and environmental concerns. As oil types and compositions vary globally, the BREAK-THRU® OE oil spreaders are designed for a broad spectrum of formulation types. All three BREAK-THRU® OE products are approved for use under 40 CFR 180.910 and generate only little or no foam.

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BREAK-THRU® OE 440 is recommended for formulations containing vegetable oils and is typically used between 0.5–5 wt% of the oil. It must be added as a compo-nent of the oil phase and not post added to the finished formulations. On a hydro-phobic surface, this product increases the spreading of seed oil droplets by 300 to 500 percent after 30 minutes.

BREAK-THRU® OE 441 is recommended for EC or OD formulations containing methylated or ethylated vegetable oils and is effective at concentrations between

2–5 wt% of the oil phase. On a hydropho-bic surface, this product at 5 wt% enhanc-es methylated seed oil to improve spread-ing five fold. Since BREAK-THRU® OE 441 is also soluble in water it can be used in SC, SL, EW and SE formulations. Accelerated studies at pH 4–9 refute the concerns of hydrolytic instability for this robust product.

BREAK-THRU® OE 444 is recommended for formulations containing mineral oils at 0.5–5 wt% of the oil phase. Field studies with BREAK-THRU® OE 444 on several

fruits confirm that it leads to improved fo-liar coverage and efficacy with fungicides and insecticides. Addition of only 0.5 wt% to a mineral oil or paraffinic oil results in spreading up to a five fold increase after thirty minutes.

Benefits of Oil Enhancers:• Improve pesticide performance• Approved under 40 CFR 180.910• Benign toxicity & ecotox• Soluble in most common solvents• Low use rates

Solubility of selected BREAK-THRU® Oil Enhancers (5 wt%) in different oils

Solvent BREAK-THRU® OE 440 BREAK-THRU® OE 441 BREAK-THRU® OE 444

Water Insoluble Soluble Insoluble

Methyl soyate, methylated rape seed oil Soluble Soluble Soluble

Vegetable Oil e.g. rapeseed oil, soya oil Soluble Dispersible Dispersible

Mineral Oil Insoluble Soluble Soluble

Paraffinic Oil Insoluble Insoluble Soluble

Solvesso® 150* Soluble Soluble Soluble

Others: Butanol, NMP, Cyclohexanone Soluble Soluble Soluble (only in butanol)

* Registered trademark of Exxon Mobil

Oil enhancers allow oil droplets to move to the back of fruits even though the oil was only sprayed on one side

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Wetting Agents

While all wetting agents have the ability to decrease surface tension, silicone wet- ting agents stand out in their ability to do so at concentrations between 0.02 to 0.15 wt%. Some of them also cause super spreading of the spray solutions whereas others – designed solely to reduce surface tension – behave as penetrants. For high-performance applications, our organo-modified siloxanes are perfectly suited to meet varying requirements.

Owing to their ultra low static surface tensions, trisiloxane surfactants can pro-vide superior spray coverage and are unique among surfactants in their ability

to impart phenomenal spreading charac-teristics to formulations. These products can also be instrumental in enabling sto-matal flooding and cuticular penetration. These surfactants can decrease the spray volume required for a particular pesticide application, allow for better targeting, and increase pesticide up-take.

Example of a trisiloxane based Super SpreaderThe results of field trials on grapes in Italy with the super spreader BREAK-THRU® S 240, used as tank-mix adjuvant, are shown in Diagram 1. Despite a lower amount of pesticide, and the lower spray

volume of only 250 l/ha the efficacy was equal or better than the full rate of the fungicide (Ortiva® = azoxystrobin*) at the higher water volume.

Example of a trisiloxane based Super PenetrantImproved penetration of a pesticide is not necessarily the result of super spreading, it can also be caused by the reduction in sur-face tension of the spray mixture and is critical for enhanced active ingredient up-take. In the case of the non-spreading trisi-loxane surfactant, BREAK-THRU® S 233, up-take of glyphosate is faster and more pronounced compared to a super spreader

Water treated with a trisiloxane surfactant can penetrate dense and hydrophobic surfaces like broccoli.

Trisiloxane based Wetting Agents

*Registered trademark of Syngenta

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Diagram 1: Increased efficacy with BREAK-THRU® S 240 with reduced spray volumes

Efficacy against grape powdery mildew (%)

Spray volume •500 l/ha •250 l/ha

Ortiva®

0.75 l/haOrtiva®

0.5 l/haOrtiva®

0.5 l/haOrtiva®

0.5 l/ha

90

85

80

75

70

65

without additional surfactant

+ 200 ml/haBREAK-THRU® S240

b*

c

a

b

Diagram 2: Up-take [%] of 14C labeled glyphosate in bean leaves as a function of time: Comparison of different mode of action between BREAK-THRU® S 240 and S 233

Glyphosate up-take [%]

Time after application

10 min 24 h

90

80

70

60

50

40

30

20

10

0

* All values with the same letter are statistically not different at P = 0.05

b*

c

a

d

e.g. BREAK-THRU® S 240, even though both products decrease the surface tension of the spray mixture down to 21 mN/m.

The speed of uptake was analysed with radiolabeled glyphosate (see Diagram 2). Bean leaves were washed at different time intervals to quantify the rate of uptake (Ref. Weed Science 2007, 55, p. 406-411). Used with glyphosate, BREAK-THRU® S 233 can enhance the speed and volume of uptake, improving rainfastness and efficacy. This class of super penetrants, such as BREAK-THRU® S 233, is most suitable for actives with systemic action.

+ 0.1 % BREAK-THRU® S 240 + 0.1 % BREAK-THRU® S 233

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Due to their extended siloxane backbone, the silicone character of BREAK-THRU® OE 441 and BREAK-THRU® S 243 is pro-nounced. The mode of action of these products is similar to that of penetrants. These products display solubility in either oil or water. The reduction in surface ten-sion of these products is not so dramatic as for trisiloxanes, but polysiloxanes have a great impact on the properties of oils (see oil enhancer section). While organomodi-fied trisiloxanes require relatively neutral formulating conditions, organomodified

polysiloxanes do not and BREAK-THRU® OE 441 and BREAK-THRU® S 243 are sta-ble in water at pH values between 4 – 9.

In the table below, the stability towards hydrolysis was analysed by monitoring the static surface tension (mN/m).

Compatibilty and mode of action drive the selection of the most suitable wetting agent. Details are available upon request. Specifically for SL formulations some-times the combination of a trisiloxane

with a solubilizer or amphoteric surfactant is advantageous. For more detailed recommendations please contact us.

Benefits of Wetting Agents: • Safeguarding the performance

of pesticides • Allow wetting of dusty or hard

to wet plants • Allow reduction of spray volumes

by up to 30–50 %• Greater or equal up-take of pesticide

in less time, thus improved rainfastness

Stability of BREAK-THRU® OE 441 in water static surface tension [mN/m]

pH 3 pH 4 pH 9 pH 11

1 wt% solution (0 h) 38 38 37 38

1 wt% solution (7d at 54 °C) 40 39 38 41

Properties of our wetting agents

Product Chemical description

Stable wi-thinpH range

Static surface tension @ 0.1 % in water

Foam tendency

EPA FIFRA status

BREAK-THRU® OE 441Organomodified Polysiloxane 4–9 40 Low

40 CFR 180.910

BREAK-THRU® S 200Organomodified Trisiloxane 5–8 22 High

40 CFR 180.910

BREAK-THRU® S 233Organomodified Trisiloxane 5–8 23 High

40 CFR 180.910

BREAK-THRU® S 240Organomodified Trisiloxane 5–8 22 High

40 CFR 180.910

BREAK-THRU® S 243Organomodified Polysiloxane 4–9 47 High

40 CFR 180.910

BREAK-THRU® S 279Organomodified Trisiloxane 5–8 21 High

40 CFR 180.910

pH stable Polysiloxane based Spreaders

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By using BREAK-THRU® wetting agents grapes are uniformly wetted

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Antifoams

While silicone oils are excellent defoam-ers, they are notoriously immiscible in water-based systems. To overcome this obstacle, Evonik has a line of defoamer/antifoam products with the BREAK-TH-RU® AF designation. These silicone prod-ucts are modified with other organic groups and are tailor-made to overcome incompatibility, while maintaining the efficiency and low dose rates typical of silicone oils.

Since individual formulations contain dif-ferent active ingredients, solvents and surfactants, a universal solution to foam-ing issues does not exist. BREAK-THRU® AF antifoam agents are very robust in their performance and are used in a variety of formulations. Please contact us to discuss your specific application.

For example, glyphosate IPA SL formula-tions often contain tallow amine ethoxyl-

ates, which cause foam when agitating the spray solution. A 360 g/l a. e. glypho-sate IPA salt formulation was prepared with 10 % v/v TAE-151 and different con-centrations of BREAK-THRU® AF 9903. After mixing the components, each for-mulation was then diluted 1 : 50, and 50 ml were added to a 100 ml graduated cylinder. Following vigorous shaking for 15 s, the foam height was recorded.

1 TAE-15: tallow amine ethoxylate with 15 mole EO, available from Evonik as VARONIC® T-215**

Benefits of BREAK-THRU® Antifoams:• Tailored to overcome incompatibility,

while maintaining the efficiency • Variety of different chemistries to fulfill

different application requirements

Defoaming of a 360 g/l a. e. glyphosate formulation

Concentration ofBREAK-THRU® AF-9903

Initial Foam Height (ml)

Foam Heightafter 90 sec. (ml)

Control 60 50

0.0165 % 48 1

0.05 % 25 –

0.15 % 13 –

In agrochemical formulations, different surface active chemistries are used as wetting agents, emulsifiers, dispersants, compatibilizers and even as solvents. Many of them tend to concentrate at interfaces often generating and stabilizing foam. Foaming can occur during manufacturing and packaging, but can also occur during field application where it is especially burdensome to end users.

Laurylethersulfate APG control without antifoam* Alkylpolyglycoside = APG ** Registered trademark by Evonik

Foam control with 0.1 wt% BREAK-THRU® AF-9903

Trisiloxane APG*

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Properties of selected antifoams

ProductChemical base Concentration/Form

Viscosity(mPas)

EPA FIF-RA status Special properties

BREAK-THRU® AF-5503 OMS* 100/EC** 60040 CFR 180.910

For water based formulations, salt tolerant; causes less cloudiness than AF 9903 in SL formulations

BREAK-THRU® AF-9902 OMS 100/Compound500– 1000

40 CFR 180.910

Antifoam for in-can formulations; not self-emul-sifying; suitable for oil based formulations

BREAK-THRU® AF-9903 OMS 100/EC500– 1500

40 CFR 180.910

For water based formulations, salt tolerant e. g. for glyphosate

BREAK-THRU® AF-9906Silicone oil 100/Compound

200– 600

40 CFR 180.910

Antifoam concentrate without emulsifier for non-aqueous or solvent based systems (e. g. ODs)

BREAK-THRU® AF-9908Silicone oil/OMS 40/Emulsion 300 Not listed

Increased stability towards temperature and shear; suitable for granule preparation

*OMS = Organomodified siloxane **EC = self-emulsifying concentrate

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Dispersing agents are surfactants which enhance the incorporation of solids into liquids and are used in suspension concentrates and more recently in oil dispersions. Dispersing agents interactwith the surface of the particles and prevent the formation of agglomerates.

Dispersing Agents

Dispersing agents have amphiphilic structures which need to be insoluble in the solvent. They must possess ancho-ring groups capable of being strongly absorbed onto the particle surface.

Some examples for the incorporation of BREAK-THRU® dispersing agents (DA series) in SCs and ODs are given in the section “formulation activities”.

Benefits of Dispersing Agents:• Enhanced wetting of solid particles and

increased stability of formulations• Reduced milling time• Improved dispersion in water

Properties of selected dispersing agents

Product Chemical descriptionConcen-tration

Formu- lation suitability

EPA FIF-RAstatus

BREAK-THRU® DA 646 Modified polyether 100 % EC, SC not listed

BREAK-THRU® DA 652 Fatty acid derivative 100 % OD not listed

BREAK-THRU® DA 655Polyether phosphate, electrostatical stabilisation 100 % OD not listed

BREAK-THRU® DA 675

Aqueous based organi-cally modified polymer; sterical stabilisation 40 % SC not listed

BREAK-THRU® DA 752 W

Aqueous based organi-cally modified polymer; electrostatical stabilisation 50 % SC not listed

BREAK-THRU® EM TD 6POE (6) isotridecyl ether 100 % OD

pending EPA approval

Without BREAK-THRU® DA 655 With BREAK-THRU® DA 655

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Emulsifiers

BREAK-THRU® emulsifiers (BREAK-THRU® EM series) are non-ionic, hydrophilic and lipophilic organic surfactants used in the preparation of both oil-in-water and wa-ter-in-oil emulsions. By balancing the hy-drophilic and lipophilic parts the proper-ties of a surfactant can be adjusted to the needs of different applications. Therefore BREAK-THRU® emulsifiers can also be used as dispersants, solubilizers and wet-ting agents.

To emulsify a specific oil, emulsifiers with precisely adjusted HLB values are needed. The required HLB value can be adjusted by selected blending. Our regional technical service group will assist you in finding the right formulation. Rely on our long-standing experience and know-how and save valuable time.

BREAK-THRU® EM V 20 is one of our vegetable-based nonionic emulsifiers with excellent ecological, toxicological

and dermatological behavior. This surfac-tant also reduces the surface tension of oils (e.g. sunflower or rapeseed oil) with-out any foam. With an HLB-value of 8,4 it creates emulsion spontaneity in ECs and EWs. During screening of various emulsifiers with a pyrethroid EC formula-tion it demonstrated superior perfor-mance (see publication Poffenberger et. al ISAA 2007). In herbicide field trials this product showed higher biological ef-ficacy than methylated rapeseed oil, even at lower dose rate. No phytoxicity was exhibited in wheat and maize field trials.

Benefits of glycerol fatty acid esters: • Excellent emulsifying and stabilizing

properties • Excellent solubility in vegetable

and synthetic oils • Derived from renewable resources • No skin irritation, benign tox

classification

Properties of selected* liquid emulsifiers

Product Chemical base HLB Recommended oil EPA FIFRA status

BREAK-THRU® EM V 20POE-(20)-Glyceryl Oleoricinolate 8.4

Vegetable oil, recommended in combination (5:1) with co-emulsifier Tegin OV, total dose 15 % 40 CFR 180.910

BREAK-THRU® EM 0 7 PEG-(7)-Oleate 10 Paraffinic oil, dose rate 10 % 40 CFR 180.910

BREAK-THRU® EM TD 6POE-(6)-Isotridecyl Ether 11,4

Mineral oil, preferred 1:1 mixture with TEGO® SMO 80 V (20 %)

Pending EPA approval

* In order to obtain the whole emulsifier portfolio brochure, please contact our regional technical groups

Our product range includes primary and secondary emulsifiers that are based on renewable resources like ethoxylated or non-ethoxylated glycerol fatty acid esters, sorbitan esters, various fatty acid polyglycol esters and lauryl polyglycol ethers. However, our focus is on the more environmentally friendly glycerol fatty acid esters.

BREAK-THRU® EM, for excellent emulsification

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Formulation Activities

Suspension Concentrate Formulation

We at Evonik decided to develop prototype formulations to provide guidance to the user with respect to product selection. For us the aim is to give you the ability to differentiate your for-mulation in the market place by offering superior agrochemical products. Various examples of ongoing activities with different liquid formulation types are described on the next pages.

Suspension concentrate (SC) formulations have gained popularity as a means of de-livering water insoluble actives in a liquid formulation without need for solvents. Creating a stable, effective and environ-mentally friendly formulation requires the use of surfactants. In the following exam-ple, an SC formulation (see recipe below) containing sulfur and BREAK-THRU® DA 646 as the dispersing aid was com-pared with a formulation containing ethoxylated tristyrylphenol phosphate (TSP), a commonly used dispersing agent.

Preparation of the formulationGrinding was accomplished with all of the ingredients except the thickener with a corrugated teflon rotor blade for 2 hrs at 625 rpm using glass beads. The glass beads were filtered off and the thickener was added at the end of the milling. While both dispersing agents produce

similar particle sizes (d50 of 3.11 μm), the physical stability of the formulation fa-vored the use of BREAK-THRU® DA 646. Formulation stability was evaluated using a LUMiFuge® 116 (L.U.M. GmbH, Berlin, Germany; www.lum-gmbh.de) – a de-vice which can measure transmission profiles during centrifugation. A clear phase developed on the surface of the formulation containing the TSP (see Dia-gram 1 a). The red curve describes the beginning, the green curve the end of the lumifuge cycle. Sedimentation is ob-served for the TSP containing formula-tion between 110 and 113 mm. The top of the sample is at 95 mm, the bottom at 113.5 mm. From the movement of the phase boundary, one can estimate that this formulation will form a clear top lay-er under normal storage conditions at a rate of 1.2 mm per month. The sedimen-tation speed of the BREAK-THRU® DA

646 containing formulation was reduced by a factor of fifteen (see Diagram 1b).

The efficacy of both formulations and a commercial sulfur SC formulation were tested in a greenhouse environment on powdery mildew colonized on barley (see Diagram 2). Results showed a significant improvement of the BREAK-THRU® DA 646 containing formulation over the other formulations at the intermediate dosage level (see Fleute-Schlachter et al. pro-ceedings ISAA 2004, South Africa, ISBN 1-920-01716-X). It is believed that the im-proved efficacy can be attributed to the lower static and dynamic surface tension imparted by the BREAK-THRU® DA 646 which was confirmed in the laboratory. To further enhance the biological efficacy it is recommended to incorporate a trisi-loxane based wetting agent, such as BREAK-THRU® S 240 at 1-8 wt%.

Guideline recipe of the SC formulation

Component wt%

Sulfur (Mesh 100) 25.1

Dispersing agent 1.6

Tego® Antifoam MR 2021 0.3

BREAK-THRU® S 240 0–8.0

Monoethylene glycol (antifreeze) 2.5

Xanthan gum, 10 % solution 1.8

Water to 100

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Diagram 2: Number of powdery mildew pustules per leaf segment of barley

Treatment Control31 mg S/l

500 mg S/l

2000 mg S/l

Untreated 168 a* – – –

Formulation with BREAK-THRU® DA 646 – 147 b 1 d 0 d

Formulation with TSP – 145 b 30 c 0 d

Commercial formulation WG 80 % – 164 ab 38 c 20 cd

*All mean values with the same letter are statistically not different at P=0.05

a) with TSP

Tran

smiss

ion

[%]

Position [mm]

120,0

108,0

96,0

84,0

72,0

60,0

48,0

36,0

24,0

12,0

0,095 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115

b) with BREAK-THRU® DA 646

Tran

smiss

ion

[%]

Position [mm]

120,0

108,0

96,0

84,0

72,0

60,0

48,0

36,0

24,0

12,0

0,095 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115

Diagram 1: Stability of a formulation tested in the LUMiFuge

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Regulatory pressure and the chemistry of certain modern active ingredients have given rise to Oil Dispersion (OD) formu-lations. OD formulations represent a sig-nificant challenge for pesticide formula-tions and require unique dispersing agents and emulsifiers. We at Evonik addressed this challenge and have tested various ad-ditives for oil dispersing systems.

Typically sulfonylurea actives are formu-lated as water dispersable granules (WDG) because they are sensitive to hy-drolysis. Tank-mix adjuvants are recom-

mended for these formulations as the up-take of the active ingredient is slow. Liquid formulations are more convenient as this kind of formulation type incorpo-rates an effective adjuvant which can in-crease and broaden weed control. Evonik has developed an OD formulation which delivers on both counts.

The goal of this particular example was to create a sulfonylurea formulation with improved stability and biological perfor-mance compared to commercial standards.

Guideline recipe of a 40 g/l OD sulfonylurea formulation

Component wt%

Active 4.5

Oil component 61.5

BREAK-THRU EM Emulsifier mix 20

BREAK-THRU OE Oil enhancer 5.0

BREAK-THRU DA Dispersing agent 5.0

Thickener 4.0

Oil Dispersion Formulation

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Preparation of the formulationGrinding was accomplished with all of the ingredients except the thickener with 3 cylindrical rotating blades for 1 hour at 1000 rpm using glass beads. The tempera- ture should not exceed 20 °C during grinding, therefore cooling is necessary.

After this time the thickener is added and an additional 1.5 hrs of milling should be done in order to create very small parti-cles (d50 < 5 μm).

ResultsOur efforts resulted in a sulfonylurea for-mulation with 40 g/l load, which is easy to handle due to its low viscosity (28 mPas). The chemical stability of the for-mulation was analyzed by HPLC (modi-fied CIPAC method 709). The physical stability was analyzed according to the CIPAC accelerated storage test at 54°C judging the sedimentation behavior.

The biological efficacy of the Evonik for-mulation was evaluated in the glass house as well as in the field and showed better results than a commercial standard. In

addition, the emulsification behavior was also improved, see picture above.

In the glass house two slightly different Evonik OD formulations were compared to a commercial standard to control Poa pratense. For each formulation 3 pots have been used as replications. The spray volume was equivalent to 200 l/ha. Within the testing two different dose rates have been used, 10 and 2.5 g ai/ha, cor-responding to 250 or 62.5 ml of formula-tion per ha. The 30 DAT assessment data are shown below.

Biological efficacy of different formula-tions against Poa pratense 30 DAT [%]*

2.5 g ai/ha 10 g ai/ha

Commercial standard 60 74

Evonik formulation 1 81 90

Evonik formulation 2 62 100

* Note that suboptimal a.i. rates were chosen to differentiate the formulations. Normal field rates would be 40 g a.i./ha.

Emulsification behavior of the Evonik formulation (left) compared to a com-mercial standard (right)

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Emulsifiable concentrate (EC) formula-tions are popular formulations for oil soluble active ingredients. A proper sur-factant system is necessary in EC formula-tions to ensure spray tank stability, rapid emulsification, and plant wetting.

The goal of this particular example was to create a clodinafop formulation with simi-lar stability and performance to a com-mercially available 80 g/l standard, but without a nonylphenol ethoxylate.

Overall, the formulation matched the commercial standard in terms of efficacy when tested against black grass (Alepe-curus myosuroides) in winter wheat. In addition, the Evonik formulation showed improved stability at low temperatures (see table formulation properties).

Formulation Properties

Evonik Formu- lation

Commer-cial Standard

Formulation stability(24 h at -18 °C)

Liquid, clear

Turbid, gel

Formulation stability(14 d at 54 °C)

Stable, clear

Stable, clear

Emulsion stability(24 h at 4 °C)

Homo- geneous, stable

Homo- geneous, stable

Emulsion stability(CIPAC 342 ppm)

Homo- geneous, stable

Homo- geneous, stable

Biological efficacy [%] *

15 DAT 28 DAT

Evonik Formulation 72 77

Commercial Standard 65 75

*Test conducted at 0.5 l/ha in 300 l/ha spray volume

Emulsifiable Concentrate Formulation

Guideline recipe of an 80 g/l EC clodinafop formulation

Component wt%

Clodinafop active 8.2

Safener 2.1

Mineral Oil 64.7

BREAK-THRU® EM blend 20.0

BREAK-THRU® OE product 5.0

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The stability of emulsifiable concentrates (EC) and the corresponding tank mixtures can be a challenge. Because microemul-sions (ME) are thermodynamically stable, the shelf life is unlimited. Based on an Evonik patented microemulsion techno-logy – phase shift by quenching (PSQ) – production of clear and transparent MEs at room temperature is possible. This is in contrast to the phase inversion temp-erature method which requires heating and cooling.

The manufacturing of PSQ based micro-emulsions is limited to water insoluble actives and requires only simple stirring. Such a technology provides another op-tion for formulating an active. Once the microemulsion is poured into water drop-let sizes below 100 nm are formed and the resulting formulation is called a nano-emulsion. Although it sounds surprising, the addi-tion of more water will stabilize the PSQ derived nanoemulsions even further.Until now, microemulsions with particle sizes this small were only achievable by

the use of high shear or high energy de-mand and required specialized mixing equipment. The very small particle size distributions (see chart on right hand side) which are derived, are specifically useful for non-crop applications e.g. for wood protection where a small particle size is required for good penetration.

Guideline recipes (such as the one de-scribed for permethrin) for various actives are available from Evonik. The surfactants necessary to create such a microemulsion are offered by Evonik as a package.

Benefits of Evonik’s microemulsion technology at a glance:• Simple manufacturing at room

temperature • Obtained microemulsions and their

dilutions have an unlimited shelf life• Small droplet size creates superior

biological performance• Phase separation is reversible;

microemulsions are freeze-thaw stable

left: Microemulsion, middle: Microemulsion diluted to 0.5 wt % active, right: Nanoemulsion (diluted microemulsion 1:1000 with water)

Example recipe of a microemulsion concentrate based on permethrin

Component wt%

Paraffinic oil 41–31

Water 5–10

Evonik emulsifier package 33

Permethrin 21

Wetting agent 0–5

PSQ Microemulsion Technology from Evonik

Particle size distribution of a permethrin ME and an EC

Size

dist

ribut

ion,

unw

eigh

ted

01Hydrodynamic radius [nm]

10 100 1.000 10.000

0,2

0,4

0,6

0,8

1,0

* analysed by dynamic light scattering with a Malvern HPPS 3.1, Malvern Instruments Ltd. Equipment; dilutions were about 1:1000

EC ME

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Rheology Modifiers

The use of AEROSIL® fumed silica sup-ports these functionalities as a rheology modifier and anti-settling additive. As an efficient stabilizer AEROSIL® products prevent the agglomeration of active ingre-dients helping to ensure that they are evenly distributed and show a long-term stability.

The performance of AEROSIL® fumed silica in liquid formulations is based on two mechanisms. First, the silica envelops the active ingredient and prevents re- agglomeration. Second, AEROSIL® fumed silica creates a three dimensional network giving viscoelastic properties to the liquid formulation and thus avoiding the sedi-mentation of solid particles. The proper choice of AEROSIL® fumed silica com-bines an excellent anti-settling effect with a low shear viscosity.

Suspension ConcentratesTo demonstrate the influence of some of the above mentioned parameters the fig-ure shows how the yield point of a water-based AEROSIL® 200 suspension depends on the pre-adjusted pH-value and the sur-factant concentration (sorbitan mono-ole-ate). At a given surfactant concentration the yield point increases with lower pH-values. At a given pH-value, there is an optimum surfactant concentration leading to the maximum yield point.

Oil Dispersions, OD FormulationsMineral and natural oils containing active ingredients are easy to stabilize using hy-drophilic or hydrophobic AEROSIL® pro-ducts. The figure shows the strong shear thinning effect of different AEROSIL® 200 concentrations in soybean oil. AEROSIL® fumed silica establishes a yield point and prevents settling of active ingredients.

Hydrophobic AEROSIL® types in particu-lar, combine a moderate shear viscosity with a sufficient yield point. These pro-perties provide excellent suspension stabi-lization and pourability. The hydrophobic AEROSIL® grades AEROSIL® R 974 and AEROSIL® R 972 lead to a lower viscosity at a given yield point than the hydrophilic AEROSIL® 200.

Based on the selected AEROSIL® grades, the use of the hydrophilic AEROSIL® 200 leads to a distinct yield point at a low con-centration. However, this is at the ex-pense of a relatively high viscosity. If one defines a certain viscosity as the maxi-mum that is acceptable, the hydrophobic AEROSIL® grades AEROSIL® R 974 and AEROSIL® R 972 are both beneficial. The more hydrophobic AEROSIL® R 972 achieves the highest yield point at a given viscosity.

In SC and OD formulations there is a general need to protect dispersed, insoluble active ingre-dient particles against sedimentation. This can be achieved by adjusting suitable viscoelastic properties. In addition, their viscosity has to be low enough to make sure packages can easily be emptied without residue.

Yield Point using 2.5% AEROSIL® 200

3,5–4 3–3,5 2,5–3 2–2,5 1,5–2 1–1,5 0,5–1 0–0,5

23456

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0 Yield Point [Pa]

pH-value Tenside Concentration [mmol/l]

4

8

6

21

Liquid Formulations: OD (AEROSIL® 200 in Soybean Oil) Shear thinning behavior of AEROSIL® 200 at different concentrationsviscosity [mPas]

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

shear rate (1/s) 1 10 100 1000

5 wt.% AEROSIL® 200 7 wt.% AEROSIL® 200 9 wt.% AEROSIL® 200 10 wt.% AEROSIL® 200

Liquid Formulations: OD (Yield Point vs. Viscosity) Model formulation based on vegetable oil derivativeYield Point [Pa]

0,6

0,5

0,4

0,3

0,2

0,1

0Viscosity at a shear rate of 1/s (mPas)

0 1000 2000 3000 4000 5000 6000

AEROSIL® R972 AEROSIL® R974 AEROSIL® 200

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Carrier, Flow and Anti-Caking Agents

Wettable Powder formulations treated with SIPERNAT® or AEROSIL® products are dry, free-flowing and do not tend to cake on storage. In formulations which need to be dispersed in water before use, finely ground SIPERNAT® speciality silica or AEROSIL® fumed silica have to be cho-sen, as the silica must stay suspended from the moment of dispersing the for-mulation until it is sprayed onto the field. Besides, if non-milled silica types would be used, particles which are too big may also block the spray nozzles. In granules for direct application in the field, large particle size silica can be advantageous. Those grades can be used as carrier for liquid or low melting actives providing both a free flowing as well a non-caking absorbate. The granular shape of the ab-sorbate is already predesigned with the silica. No additional granulation step is necessary.

Wettable Powder (WP) and Water Dispersible Granules (WG)SIPERNAT® speciality silica provides three main functionalities to Wettable Powder and Water Dispersible Granuleformulations:

• Highly efficient absorption of liquid actives: Solid formulations containing up to 75 % of liquid active ingredient can easily be prepared using suitable SIPERNAT® grades.

• Free flow additive/anti-caking addi-tive: 1 – 3 % of SIPERNAT® speciality or AEROSIL® fumed silica added to powder or granule formulations en-hance the flowability greatly and avoid caking during storage.

• Milling aid: Adding up to 10 % of SIPERNAT® speciality silica facilitates the milling of low melting ingredients. As a positive side effect, the suspen-sability of the WP and WG at the point of use is much improved with the use of SIPERNAT® and AEROSIL® products.

Granules (GR)Hydrophobic silica on the surface of gra-nulates or dusts enables the formulator to increase stability in humid environmentsor to delay (“slow release”) the diffusion of the active ingredient. Hydrophilic SIPERNAT® 2200 is an ideal carrier for liquid or low melting actives to be con-verted to granules. Such carried actives are easy to be applied directly to the soil, will not create dust and reduce direct skin contact which facilitates their handling. SIPERNAT® 2200 is able to absorb 190 ml liquid / 100 g silica still providing a dry and free flowing formulation.

SIPERNAT® speciality silica and AEROSIL® fumed silica are used in solid formulations as flow, anti-caking and milling aids and as carriers for liquid active ingredients.

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Rheology Modifier Recommendations

Product EPA FIFRA Status Use Description

AEROSIL® OX 50

180.950Hydrophilic fumed silica which can be used as anti-settling agent/rheology modifier in SC and OD formulations.

AEROSIL® 200

AEROSIL® 300

AEROSIL® 380

AEROSIL® COK 84 180.910 + 180.950Mixture of fumed silica and fumed aluminium oxide used in water based SC formulations.

AEROSIL® R 202

180.960Hydrophobic fumed silica. Especially recommended in OD formulations for viscosity control.

AEROSIL®R 812 S

AEROSIL® R 972

AEROSIL® R 974

Carrier and Flow Agents Recommendations

Product EPA FIFRA Status Use Description

SIPERNAT® 22 (1)

180.950Hydrophilic precipitated silica can be used as carrier in WP and WG formulations

SIPERNAT® 50(1)

SIPERNAT® 22 S

SIPERNAT® 50 S

SIPERNAT® 320

SIPERNAT® 350

SIPERNAT® 22 S

180.950

Hydrophilic precipitated silica and hydrophilic fumed silica (see table above) provide good properties as flow aid and anti caking agent in WP and WG formulations.

SIPERNAT® 50 S

SIPERNAT® 350

SIPERNAT® 22

180.950Hydrophilic precipitated silica especially appropriate as grinding aid in WP and WG formulationsSIPERNAT® 50

SIPERNAT® 2200 180.950Micro-granular hydrophilic silica can be used as carrier for granules, which are directly applied to the field.

SIPERNAT® D 17 180.960Hydrophobic precipitated silica, can slow down the penetration of moisture for applications in seed coatings

(1) Grinding of the whole formulation is necessary with these products

www.evonik.com/break-thru

Asia | Pacific

Evonik Degussa Specialty Chemicals Co, Ltd. 55, Chundong Road Xinzhuang Industry Park Shanghai, 201108PR ChinaPhone +86 21 6119-1125 fax +86 21 6119-1406

The Americas

Evonik Goldschmidt Corp. 914 E. Randolph Rd. P.O. Box 1299 Hopewell, VA 23860USAPhone +1 804 541-8658 fax +1 804 541-2783

Europe | Middle East | Africa

Evonik Industries AG Goldschmidtstraße 100 45127 EssenGermanyPhone +49 201 173-2665 fax +49 201 173-1990

For more detailed information or to obtain a brochure which addresses a specific area of interest, please visit our website.

This information and all further technical advice is based on our present knowledge and experience. However, it implies no liability or other legal respon-sibility on our part, including with regard to existing third party intellectual property rights, especially pat-ent rights. In particular, no warranty, whether express or implied, or guarantee of product properties in the legal sense is intended or implied. We reserve the right to make any changes according to technological progress or further developments. The customer is not released from the obligation to conduct careful inspection and testing of incoming goods. Performance of the product described herein should be verified by testing, which should be carried out only by qualified experts in the sole responsibility of a customer. Reference to trade names used by oth-er companies is neither a recommendation, nor does it imply that similar products could not be used. (April 2008)

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