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Chemistry and Technology of Agrochemical Formulations
Chemistry and Technology of Agrochemical Formulations
Edited by
D. A. Knowles FORM-AK Formulation Consultancy Services,
Tonbridge, Kent, UK
Springer Science+Business Media, B.V.
A C.I.P cata10gue record for this book is availab1e from the Library of Congress
ISBN 978-94-010-6080-6 ISBN 978-94-011-4956-3 (eBook)
DOI 10.1007/978-94-011-4956-3
Printed on acid-free paper
AH Rights Reserved © 1998 Springer Science+Business Media Dordrecht
Original1y published by Kluwer Academic Publishers in 1998 Softcover reprint of the hardcover 1 st edition 1998
No part of the material protected by this copyright notice may be reproduced or uti1ized in any form or by any means, electronic or mechanica1,
including photocopying, recording or by any information storage and retrieva1 system, without written permission from the copyright owner.
Contents
Preface List of contributors
Xlll
xv
1 Introduction D. A. KNOWLES References
2 Review of major agrochemical classes and uses L. G. COPPING
1
7
8
2.1 Introduction 8 2.2 Future needs 9 2.3 World markets, 1996 9 2.4 Sales by category, 1995 10 2.5 Sales by crop, 1995 12 2.6 Sales by region, 1995 13 2.7 Herbicides 13
2.7.1 Photosynthesis 15 2.7.2 Amino acid biosynthesis 17 2.7.3 Lipid biosynthesis 17 2.7.4 Interference with plant hormones 18 2.7.5 Cell division 19 2.7.6 Cellulose biosynthesis 19 2.7.7 Respiratory uncouplers 19
2.8 Insecticides 20 2.8.1 Organophosphorus insecticides (OPs) 21 2.8.2 Carbamate insecticides 22 2.8.3 Insecticides that interact with neurotransmitter ligand
recognition sites 22 2.8.4 Insecticides that interfere with ion channels 23 2.8.5 Inhibition of oxidative phosphorylation 24 2.8.6 Insect growth and regulation 25 2.8.7 Compounds with uncertain modes of action 26
2.9 Fungicides 27 2.9.1 Protectant fungicides 27 2.9.2 Protein biosynthesis 28 2.9.3 Nucleic acid metabolism 28 2.9.4 Cell division 28 2.9.5 Sterol biosynthesis 28 2.9.6 Triglyceride biosynthesis 29 2.9.7 Chitin biosynthesis 29 2.9.8 Respiration 29 2.9.9 Indirectly acting fungicides 30
2.10 Plant growth regulators 30 2.11 Biological screening: discovery and development of a new agrochemical 30
2.11 .1 Chemical synthesis 31 2.11.2 Biological evaluation 35
References 38
vi CHEMISTRY AND TECHNOLOGY OF AGROCHEMICAL FORMULATIONS
3 Formulation of agrochemicals 41 D. A. KNOWLES
3.1 Introduction 41 3.2 Conventional formulations 43
3.2.1 Granules (GR) 43 3.2.2 Solution concentrates (SL) 44 3.2.3 Emulsifiable concentrates (EC) 45 3.2.4 Wettable powders (WP) 46 3.2.5 Suspension concentrates (SC) 47 3.2.6 Seed treatments (OS, WS, LS, FS) 49
3.3 New-generation formulations 50 3.3.1 General trends 50 3.3.2 Oil-in-water emulsions (EW) 51 3.3.3 Suspoemulsions (SE) 52 3.3.4 Microemulsions (ME) 53 3.3.5 ControlIed-release formulations 53 3.3.6 Water-dispersible granules (WG) 55 3.3.7 Formulations using a built-in wetter 56
3.4 Surfactants for agrochemicals 57 3.4.1 General characteristics 57 3.4.2 Adsorption and surface tension 59 3.4.3 Micellization 61 3.4.4 Krafft temperature and cloud point 61 3.4.5 Wetting and contact angle 61 3.4.6 Particle and droplet stabilization 62 3.4.7 Wetting agents 63 3.4.8 Dispersion 64 3.4.9 Emulsification 65 3.4.10 Solubilization 66 3.4.11 Bioenhancement 67 3.4.12 Conventional surfactants 67 3.4.13 Recent surfactant developments 70
3.5 Other formulation additives 71 3.5.1 Carriers and diluents 71 3.5.2 Solvents 71 3.5.3 Anti-settling agents 73 3.5.4 Water-soluble polymers 74 3.5.5 Preservatives 75 3.5.6 Anti-freeze agents 78 3.5.7 Anti-foam agents 78 3.5.8 Anti-caking agents 78
References 79
4 Water-dispersible granules 80 G. A. BELL
4.1 Introduction 80 4.2 Manufacturing methods 83 4.3 Physical properties 87
4.3.1 Granule size and shape 88 4.3.2 Particle assemblies and structures 91 4.3.3 Quantity and type of binders 98
4.4 Design: modern methods 112 References 114
5
6
CONTENTS
Recent developments on safer formulations of agrochemicals P. J. MULQUEEN
5.1 Introduction 5.2 Liquid formulations
5.2.1 Emulsifiable concentrates (EC) 5.2.2 Concentrated emulsions (CE) 5.2.3 Suspension emulsions (or suspoemulsions) 5.2.4 Microemulsions 5.2.5 Multiple emulsions 5.2.6 Suspension concentrates
5.3 Controlled-release formulations 5.3.1 Methods of encapsulation 5.3.2 Advantages of microencapsulation 5.3.3 Microencapsulated products 5.3.4 Future trends in microencapsulation
5.4 Water-soluble packaging 5.5 Dry products (water-dispersible granules) 5.6 Adjuvants 5.7 Other formulation types
5.7.1 Seed treatment formulations 5.7.2 Biotechnological improvements
5.8 Summary and future possibilities References
Agrochemical formulations using natural lignin products S. T. HUMPHREY
6.1 Introduction 6.1.1 Lignosulphonates: some basic information 6.1.2 Lignin modification
6.2 Wettable powders (WP) 6.2.1 Formulation 6.2.2 Production methods
6.3 Water-dispersible granules (WG) 6.3.1 Formulation 6.3.2 Production methods
6.4 Suspension concentrates (SC) 6.4.1 Formulation 6.4.2 Production methods
6.5 Oil-in-water emulsions (EW) 6.5.1 Formulation 6.5.2 Production methods
6.6 Controlled release 6.6.1 Granules 6.6.2 Tablets 6.6.3 Gels 6.6.4 Microencapsulation
6.7 Ultraviolet protection 6.8 Compatibility agents 6.9 Adjuvants 6.10 Complexing agents 6.11 Environmental and regulatory information
6.11.1 Personnel 6.11.2 Environmental
References
vii
121
122 125 125 126 130 131 131 132 132 134 142 146 147 147 148 148 149 149 149 152 154
158
158 158 159 160 160 162 163 164 166 167 167 170 172 172 172 172 173 173 173 174 175 176 176 177 177 177 177 178
viii CHEMISTRY AND TECHNOLOGY OF AGROCHEMICAL FORMULATIONS
7 Novel surfactants and adjuvants for agrochemicals 179 S. REEKMANS
7.1 Polymeric surfactants and stability 179 7.1.1 Introduction 179 7.1.2 (De)stabilization of colloidal systems 179 7.1.3 Colloidal stabilization 180 7.1.4 Structure of polymeric surfactants for steric stabilization 183 7.1.5 Polymeric surfactants in agricultural formulations 187 7.1.6 Conclusion 195
7.2 Trends towards environmentally safer surfactants 196 7.2.1 Surfactants and the environment 196 7.2.2 Toxicity and biodegradation 197 7.2.3 Hazard labelling of surfactants 204 7.2.4 Effect of chemical structure 204 7.2.5 New-generation surfactants 209 7.2.6 Conclusion 211
7.3 Enhancing biological activity using adjuvants 212 7.3.1 Introduction 212 7.3.2 Relevance of a surfactant's properties 213 7.3.3 Built-in activators and spray-tank mixtures 220 7.3.4 Future trends in surfactants and adjuvants 221 7.3.5 Conclusion 226
Acknowledgements 226 References 226
8 Improving agrochemical performance: possible mechanisms for adjuvancy 232 P. J. HOLLOW A Y
8.1 Introduction 232 8.2 Chemical composition of adjuvants 233
8.2.1 Surfactants 233 8.2.2 Emulsifiable oils 237 8.2.3 Polymers 239 8.2.4 Polymer-forming compounds 240 8.2.5 Phospholipids 240 8.2.6 Inorganic salts 241 8.2.7 Other ingredients 241
8.3 Mechanistic approaches for investigating adjuvancy 241 8.3.1 Atomization 241 8.3.2 Retention 244 8.3.3 Predicting retention performance 246 8.3.4 Spreading and coverage 250 8.3.5 Uptake and translocation 252 8.3.6 Predicting uptake enhancement performance 253
8.4 Future prospects 257 Acknowledgements 259 References 260
9 Packaging of agrochemicals 264 P. D. CURLE, C. D. EMMERSON, A. H. GREGORY, J. HARTMANN and P. NIXON
9.1 Selection of packaging types 264 9.1.1 Selection of packaging materials for solid
formulations 264
CONTENTS ix
9.1.2 Selection of packaging materials for liquid formulations 267 9.1.3 Plastics 267 9.1.4 Metal 269 9.1.5 Glass 269 9.1.6 Recommended tests to be carried out on the main types of
containers 269 9.1.7 Specifications 271 9.1.8 Packaging instructions 271
9.2 Closures 272 9.2.1 Prevention of leakage 272 9.2.2 Tamper evidence 273 9.2.3 Closure diameter - liquid products 274 9.2.4 Dispensing liquid products from packs designed for pouring 275
9.3 Labelling 277 9.4 Shelf life 278 9.5 Pack design with regard to easy rinsing and disposal 279 9.6 Types of secondary packaging 279
9.6.1 Unit cartons 281 9.6.2 Combination with primary pack 281 9.6.3 Methods for protection of unit loads 281
9.7 United Nations performance tests 281 9.8 Rinsing methods 283 9.9 Closed transfer systems 285 9.10 Collection of containers after use 287 9.11 Summary of key design criteria 289 9.12 Returnable packaging systems 289
9.12.1 Small-volume returnable containers 289 9.12.2 SVR design criteria 290 9.12.3 Stewardship 290 9.12.4 Closures 291 9.12.5 Labelling and marking 291 9.12.6 Handling 291 9.12.7 Disposal 291
9.13 ECPA standard SVR interface 291 9.13.1 Container interface/extractor valve 291 9.13.2 Coupler 292 9.13.3 Extractor valve and coupler combined 293
9.14 Future direction 295 Glossary of terms and definitions 295 Bibliography 299
10 Application techniques for agrochemicals G. A. MATTHEWS
10.1 Hydraulic nozzles 10.1.1 Types of hydraulic nozzle
10.2 Portable sprayers 10.3 Tractor sprayers
10.3.1 Portable lines 10.3.2 Orchard sprayers
10.4 Aerial application 10.5 ULV and CDA ground application 10.6 Fogs, mists and aerosols
10.6.1 Mists 10.7 Electrostatically charged applications 10.8 Chemigation 10.9 Granule, dust and seed treatments
10.9.1 Seed treatment
302
302 308 312 315 320 320 321 324 327 328 329 330 331 332
X CHEMISTRY AND TECHNOLOGY OF AGROCHEMICAL FORMULATIONS
10.lD Miscellaneous lD.lD.1 Weed wiper lD.10.2 Lure and kill lD.10.3 Tree injection
10.11 Standards References
11 Regulatory requirements in the European Union W. K. DE RAAT, I. A. VAN DE GEVEL, G. F. HOUBEN and B. C. HAKKERT
332 332 332 332 333 333
337
11.1 Introduction 337 11.2 Some basic features of 911414/EEC 339
11.2.1 Which plant protection products? 339 11.2.2 Authorization of active substances and plant protection products 339 11.2.3 Existing and new active substances 340 11.2.4 Harmonization of methods and procedures 341 11.2.5 Quality standard 341 11.2.6 Mutual recognition 342 11.2.7 Data protection 342 11.2.8 Exemptions from the 'standard' authorization procedures 343
11.3 Overview of authorizations 344 11.4 Data requirements 345 11.5 Dossier preparation 348 11.6 Inclusion of active substances in Annex I of 911414/EEC 353
11.6.1 Introduction 353 11.6.2 Initial evaluation 355 11.6.3 Detailed evaluation and the preparation of the monograph 356 11.6.4 Procedure 361
11.7 Authorization of plant protection products 361 11.7.1 General requirements 361 11.7.2 The Uniform Principles 362 11.7.3 Evaluation 363 11.7.4 Authorization criteria 366
11.8 Transitional measures and the review programme 370 11.8.1 Transitional authorizations 370 11.8.2 Review programme 371
11.9 Adjuvants 374 Acknowledgements 374 Appendix l1.A An overview of European Community general legislation
associated with plant protection products 375
12 Regulatory requirements in the USA J.M. WAGNER
12.1 Introduction 12.2 Federal pesticide laws
12.2.1 Federal Insecticide, Fungicide, and Rodenticide Act 12.2.2 Federal Food, Drug, and Cosmetic Act 12.2.3 Food Quality Protection Act, 1996
12.3 EPA Office of Pesticide Programs 12.3.1 Organization 12.3.2 Operating objectives
12.4 Product registration: obtaining a license to sell 12.4.1 Experimental Use Permit 12.4.2 Registration 12.4.3 Tolerances and exemptions from tolerances
377
377 377 378 379 379 383 384 385 386 386 387 393
CONTENTS
12.5 Registration and tolerance data requirements 12.6 Data evaluation
12.6.1 EPA risk assessment process 12.6.2 Industry interaction with EPA: practical advice
12.7 Data protection and compensation 12.8 Reregistration and product defense
12.8.1 Data Call-In and industry task force groups 12.8.2 Special review process and cancellation of registrations
12.9 Product labeling 12.10 State registration requirements 12.11 Conclusions Acknowledgements Appendix 12.A Index of EPA study guidelines Appendix 12.B Sources of registration information Appendix 12.C Office of Pesticide Programs: senior EPA contacts References
13 Waste management and disposal of agrochemicals K. S. JOHNSON
Xl
397 397 402 403 404 405 406 406 407 409 411 412 412 412 415 416
418
13.1 Introduction 418 13.2 Site management responsibilities 418 13.3 Waste minimization 419
13.3.1 General principles and definitions 419 13.3.2 Examples of source reduction options 420 13.3.3 Example of recycling, use and reuse of waste and reclamation 421
13.4 Waste types 422 13.5 Waste handling 422
13.5.1 Operator safety 422 13.5.2 Workplace designated waste collection areas 423 13.5.3 Site waste collection 423 13.5.4 Secure waste storage 423 13.5.5 Waste preparation prior to disposal 423 13.5.6 Detoxification of containers 427 13.5.7 Toxic wastes 428
13.6 Documentation and records 428 13.6.1 Waste producer (originator) 428 13.6.2 Identification 428 13.6.3 Consignment 428
13.7 Waste disposal 428 13.7.1 Waste disposal options 429 13.7.2 Waste disposal contractors 429 13.7.3 Waste transfer stations 429 13.7.4 Transport 429
13.8 Treatment and disposal of aqueous effluents arising from formulation and packaging of agrochemical products 430 13.8.1 Introduction 430 13.8.2 Treatment process 430 13.8.3 Plant details and layout 431 13.8.4 Final effluent quality 431 13.8.5 Effluent disposal 434 13.8.6 Sludge disposal 434
References 434
Index 435
Preface
Agrochemical products and adjuvants are of vital importance in agriculture to protect food and fibre crops from weeds, insect pests and diseases in order to feed and clothe the ever-growing population of the world, which is expected to double over the next 50 years. The total world market for agrochemical products has been estimated at more than US$30 billion in 1997 and the industry plays an important part in the economies of most countries.
Enormous changes have taken place in the chemistry and technology of agrochemicals over the last 20 years or so, and therefore it is timely that a new book should be published to review the most important areas of technology and legislation in the research and development of new products, and to describe the current and likely future trends which will carry the industry forward into the next millennium.
In recent years there have been increasing pressures from governments and regulatory authorities to produce new agrochemical products which are safer to the user and have a reduced impact on the environment in general. Consequently, agrochemical companies and other organizations have been reviewing their product/pack strategies to provide products which are effective at low doses and have low toxicity to mammals and other non-target life forms. There is an increasing trend towards the use of water-based formulations, water-dispersible granules and controlled-release formulations. Improvements are taking place in safer and more convenient packaging of products. Spray application techniques are also being developed to improve targeting on the crop and reduce waste in the field. Effluent treatment and waste minimization technologies are also well advanced in the factory and on the farm. New standards are being set to control and regulate the use of agrochemical products.
The use of surfactants and other additives to give special effects and to impart long-term product stability is another rapidly developing area of technology. Surfactant and oil-based adjuvants are also being used to enhance the biological activity of active ingredients, either as part of the formulation or as spray tank additives. These important aspects of bioenhancement are reviewed and future trends are highlighted.
This book brings together well-known experts from a number of agrochemical companies, formulation additives and adjuvants suppliers, consultancies, academic and other organizations with many years of practical experience of the most important aspects of the chemistry and
xiv CHEMISTRY AND TECHNOLOGY OF AGROCHEMICAL FORMULATIONS
technology of agrochemical formulations. One of the aims of the book is to show how the various technologies are linked together in the development of new-generation user and environmentally friendly agrochemical products. Future trends in all of these areas are discussed fully and should provide the basis for safe technology into the next millennium.
This book would not have been possible without the cooperation of a wide range of authors involved in the agrochemical business, and I am indebted to them for their timely contributions, the comprehensive reviews of their special subject areas and for their insight into likely future trends.
Finally, I would like to dedicate this book to the memory of my wife Mary who, despite her own serious illness, gave me a great deal of support and encouragement during the long hours of preparation of the manuscript, and inspired me to complete it. Sadly, she did not live to see the book published.
D. A. Knowles Tonbridge, 1997
Contributors
G. A. Bell Zeneca Agrochemicals, Jealott's Hill Research Station, Bracknell, Berkshire RG42 6ET, UK
L. G. Copping LGC Consultants, 34 Saxon Way, Saffron Walden, Essex CB114EG, UK
P. D. Curle Dow AgroSciences, Crossbank Road, King's Lynn, Norfolk PE30 2JD, UK
W. K. de Raat OpdenKamp Consultancy Group, Koninginnegracht 23, 2S14 AB The Hague, The Netherlands
C. D. Emmerson AgrEvo Ltd, Cambridge Road, Hauxton, Cambridge CB2 SHU, UK
A. H. Gregory Pac-Tech, Treetops, Scotland Close, Haslemere, Surrey GU27 3AE, UK
XVI CHEMISTRY AND TECHNOLOGY OF AGROCHEMICAL FORMULATIONS
B. C. Hakkert TNO Nutrition and Food Research Institute, Department of Occupational Toxicology, PO Box 360, 3700 AJ Zeist, The Netherlands
J. Hartmann Bayer AG, Alfred Nobel Strasse 50, D-40789 Monheim, Germany
P. J. Holloway IACR-Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, Long Ashton, Bristol BS41 9AF, UK
G. F. Houben TNO Nutrition and Food Research Institute, Department of Occupational Toxicology, PO Box 360, 3700 AJ Zeist, The Netherlands
S. T. Humphrey Borregaard UK Ltd, Unit 16, Ponthenri Industrial Estate, Ponthenri, Llanelli, Carmarthenshire SA15 ITY, UK
K. S. Johnson EPEC, 78 Pound Road, East Peckham, Tonbridge, Kent TN12 5BJ, UK
D. A. Knowles FORM-AK 10 The Forstal, Hadlow, Tonbridge, Kent TNll ORT, UK
CONTRIBUTORS
G. A. Matthews International Pesticide Application Research Centre, Imperial College of Science, Technology and Medicine, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
P. J. Mulqueen Dow AgroSciences, Letcombe Laboratory, Letcombe Regis, Wantage, Oxfordshire OX12 9JT, UK
P. Nixon Novartis AG, CH-4002 Basle, Switzerland
S. Reekmans ICI Surfactants, Everslaan 45, Everberg B-3078, Belgium
I. A. van de Gevel TNO Nutrition and Food Research Institute, Department of Occupational Toxicology, PO Box 360, 3700 AJ Zeist, The Netherlands
J. M. Wagner Zeneca Ag Products, 1800 Concord Pike, PO Box 15458, Wilmington, DE 19850-5458, USA
xvii
