Chemistry and Technology of Agrochemical Formulations

Transcription

1 Chemistry and Technology of Agrochemical Formulations Edited by D. A. Knowles FORM-AK Formulation Consultancy Services, Tonbridge, Kent, UK Kluwer Academic Publishers Dordrecht / Boston / London

2 Contents Preface List of contributors xiii xv 1 Introduction 1 D. A. KNOWLES References 7 2 Review of major agrochemical classes and uses 8 L. G. COPPING 2.1 Introduction Future needs World markets, Sales by category, Sales by crop, Sales by region, Herbicides Photosynthesis Amino acid biosynthesis Lipid biosynthesis Interference with plant hormones Cell division Cellulose biosynthesis Respiratory uncouplers Insecticides Organophosphorus insecticides (OPs) Carbamate insecticides Insecticides that interact with neurotransmitter ligand recognition sites Insecticides that interlbre r with ion channels Inhibition of oxidative phbspitorylation Insect growth and regulation Compounds^ wkh-'uifcertjiin.modes.of action Fungicides Protectant fungicides. ^ \r -,, Protein biosynthesis... " ' Nucleic acid metabolism Cell division Sterol biosynthesis Triglyceride biosynthesis Chitin biosynthesis Respiration Indirectly acting fungicides Plant growth regulators Biological screening: discovery and development of a new agrochemical Chemical synthesis Biological evaluation 35 References 38

3 VI CHEMISTRY AND TECHNOLOGY OF AGROCHEMICAL FORMULATIONS 3 Formulation of agrochemicals 41 D. A. KNOWLES References Introduction Conventional formulations Granules (GR) Solution concentrates (SL) Emulsifiable concentrates (EC) Wettable powders (WP) Suspension concentrates (SC) Seed treatments (DS, WS, LS, FS) New-generation formulations General trends Oil-in-water emulsions (EW) Suspoemulsions (SE) Microemulsions (ME) Controlled-release formulations Water-dispersible granules (WG) Formulations using a built-in wetter Surfactants for agrochemicals Other General characteristics Adsorption and surface tension Micellization Krafft temperature and cloud point Wetting and contact angle Particle and droplet stabilization Wetting agents Dispersion Emulsification Solubilization Bioenhancement Conventional surfactants Recent surfactant developments formulation additives Carriers and diluents Solvents Anti-settling agents Water-soluble polymers Preservatives Anti-freeze agents Anti-foam agents Anti-caking agents Water-dispersible granules 80 G. A. BELL 4.1 Introduction Manufacturing methods Physical properties Granule size and shape Particle assemblies and structures Quantity and type of binders Design: modern methods 112 References 114

4 CONTENTS Vll Recent developments on safer formulations of agrochemicals 121 P. J. MULQUEEN 5.1 Introduction Liquid formulations Emulsifiable concentrates (EC) Concentrated emulsions (CE) Suspension emulsions (or suspoemulsions) Microemulsions Multiple emulsions Suspension concentrates Controlled-release formulations Methods of encapsulation Advantages of microencapsulation Microencapsulated products Future trends in microencapsulation Water-soluble packaging Dry products (water-dispersible granules) Adjuvants Other formulation types Seed treatment formulations Biotechnological improvements Summary and future possibilities 152 References 154 Agrochemical formulations using natural lignin products 158 S. T. HUMPHREY 6.1 Introduction Lignosulphonates: some basic information Lignin modification Wettable powders (WP) Formulation Production methods Water-dispersible granules (WG) Formulation Production methods Suspension concentrates (SC) Formulation Production methods Oil-in-water emulsions (EW) Formulation Production methods Controlled release Granules Tablets Gels Microencapsulation Ultraviolet protection Compatibility agents Adjuvants Complexing agents Environmental and regulatory information Personnel Environmental 177 References 178

5 Vlll CHEMISTRY AND TECHNOLOGY OF AGROCHEMICAL FORMULATIONS 7 Novel surfactants and adjuvants for agrochemicals 179 S. REEKMANS 7.1 Polymeric surfactants and stability Introduction (De)stabilization of colloidal systems Colloidal stabilization Structure of polymeric surfactants for steric stabilization Polymeric surfactants in agricultural formulations Conclusion Trends towards environmentally safer surfactants Surfactants and the environment Toxicity and biodegradation Hazard labelling of surfactants Effect of chemical structure New-generation surfactants Conclusion Enhancing biological activity using adjuvants Introduction Relevance of a surfactant's properties Built-in activators and spray-tank mixtures Future trends in surfactants and adjuvants Conclusion 226 Acknowledgements 226 References Improving agrochemical performance: possible mechanisms for adjuvancy 232 P. J. HOLLOWAY Introduction Chemical composition of adjuvants Surfactants Emulsifiable oils Polymers Polymer-forming compounds Phospholipids Inorganic salts Other ingredients Mechanistic approaches for investigating adjuvancy Atomization Retention Predicting retention performance Spreading and coverage Uptake and translocation Predicting uptake enhancement performance Future; prospects 8.4 Acknowledgements References Packaging of agrochemicals 264 P. D. CURLE, C. D. EMMERSON, A. H. GREGORY, J. HARTMANN and P. NIXON 9.1 Selection of packaging types Selection of packaging materials for solid formulations 264

6 CONTENTS IX Selection of packaging materials for liquid formulations Plastics Metal Glass Recommended tests to be carried out on the main types of containers Specifications Packaging instructions Closures Prevention of leakage Tamper evidence Closure diameter - liquid products Dispensing liquid products from packs designed for pouring Labelling Shelf life Pack design with regard to easy rinsing and disposal Types of secondary packaging Unit cartons Combination with primary pack Methods for protection of unit loads United Nations performance tests Rinsing methods Closed transfer systems Collection of containers after use Summary of key design criteria Returnable packaging systems Small-volume returnable containers SVR design criteria Stewardship Closures Labelling and marking Handling Disposal ECPA standard SVR interface Container interface/extractor valve Coupler Extractor valve and coupler combined Future direction 295 Glossary of terms and definitions 295 Bibliography Application techniques for agrochemicals 302 G. A. MATTHEWS 10.1 Hydraulic nozzles Types of hydraulic nozzle Portable sprayers Tractor sprayers Portable lines Orchard sprayers Aerial application ULV and CDA ground application Fogs, mists and aerosols Mists Electrostatically charged applications Chemigation Granule, dust and seed treatments Seed treatment 332

7 X CHEMISTRY AND TECHNOLOGY OF AGROCHEMICAL FORMULATIONS Miscellaneous Weed wiper Lure and kill Tree injection Standards 333 References Regulatory requirements in the European Union 337 W. K. DE RAAT,I. A. VAN DE GEVEL, G. F. HOUBEN and B. C. HAKKERT 11.1 Introduction Some basic features of 91/414/EEC Which plant protection products? Authorization of active substances and plant protection products Existing and new active substances Harmonization of methods and procedures Quality standard Mutual recognition Data protection Exemptions from the 'standard' authorization procedures Overview of authorizations Data requirements Dossier preparation Inclusion of active substances in Annex I of 91/414/EEC Introduction Initial evaluation Detailed evaluation and the preparation of the monograph Procedure Authorization of plant protection products General requirements The Uniform Principles Evaluation Authorization criteria Transitional measures and the review programme Transitional authorizations Review programme Adjuvants 374 Acknowledgements 374 Appendix 11.A An overview of European Community general legislation associated with plant protection products Regulatory requirements in the USA 377 J. M. WAGNER 12.1 Introduction Federal pesticide laws Federal Insecticide, Fungicide, and Rodenticide Act Federal Food, Drug, and Cosmetic Act Food Quality Protection Act, EPA Office of Pesticide Programs Organization Operating objectives Product registration: obtaining a license to sell Experimental Use Permit Registration Tolerances and exemptions from tolerances 393

8 CONTENTS XI 12.5 Registration and tolerance data requirements Data evaluation EPA risk assessment process Industry interaction with EPA: practical advice Data protection and compensation Reregistration and product defense Data Call-in and industry task force groups Special review process and cancellation of registrations Product labeling State registration requirements Conclusions 411 Acknowledgements 412 Appendix 12.A Index of EPA study guidelines 412 Appendix 12.B Sources of registration information 412 Appendix 12.C Office of Pesticide Programs: senior EPA contacts 415 References Waste management and disposal of agrochemicals 418 K. S. JOHNSON References Introduction Site management responsibilities Waste minimization General principles and definitions Examples of source reduction options Example of recycling, use and reuse of waste and reclamation Waste types Waste handling Operator safety Workplace designated waste collection areas Site waste collection Secure waste storage Waste preparation prior to disposal Detoxification of containers Toxic wastes Documentation and records Waste producer (originator) Identification Consignment Waste disposal Waste disposal options Waste disposal contractors Waste transfer stations Transport Treatment and disposal of aqueous effluents arising from formulation and packaging of agrochemical products Introduction Treatment process Plant details and layout Final effluent quality Effluent disposal Sludge disposal Index