Advances in Pesticide Formulation Technology

241 Pages·1984·3.814 MB·English

by  Herbert B. Scher (Eds.)

Advances in
Pesticid
Technology
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
ACS SYMPOSIUM SERIES 254
Advances in
Pesticide Formulation
Technology
Herbert B Scher EDITOR
Stauffer
Based on a symposium sponsored by
the Division of Pesticide Chemistry
at the 186th Meeting
of the American Chemical Society,
Washington, D.C.,
August 28-September 2, 1983
American Chemical Society, Washington, D.C. 1984
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
Library of Congress Cataloging in Publication Data
Advances in pesticide formulation technology.
(ACS symposium series, ISSN 0097-6156; 254)
"Based on a symposium sponsored by the Division of
Pesticide Chemistry at the 186th Meeting of the
American Chemical Society, Washington, D.C., August
28 September 2, 1983."
Bibliography.
Includes indexes.
1. Pesticides—Congresses.
I. Scher, Herbert B., 1937- . II. American
Chemical Society. Division of Pesticide Chemistry.
III. Series.
TP248.P47A38 1984 668'.65 84 6394
ISBN 0-8412-0840-9
Copyright © 1984
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PRINTED IN THE UNITED STATES OF AMERICA
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
ACS Symposium Series
M. Joan Comstock, Series Editor
Advisory Board
Robert Baker
U.S. Geological Survey
Martin L. Gorbaty Theodore Provder
Exxon Research and Engineering Co. Glidden Coatings and Resins
Herbert D. Kaesz James C. Randall
University of California—Los Angeles Phillips Petroleum Company
Rudolph J. Marcus Charles N. Satterfield
Office of Naval Research Massachusetts Institute of Technology
Marvin Margoshes Dennis Schuetzle
Technicon Instruments Corporation Ford Motor Company
Research Laboratory
Donald E. Moreland
USDA, Agricultural Research Service Davis L. Temple, Jr.
Mead Johnson
W. H. Norton
J. T. Baker Chemical Company Charles S. Tuesday
General Motors Research Laboratory
Robert Ory
USDA, Southern Regional C. Grant Willson
Research Center IBM Research Department
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
FOREWOR
The ACS SYMPOSIUM SERIES was founded in 1974 to provide
a medium for publishing symposia quickly in book form. The
format of the Series parallels that of the continuing ADVANCES
IN CHEMISTRY SERIES except that in order to save time the
papers are not typeset but are reproduced as they are sub
mitted by the authors in camera-ready form. Papers are re
viewed under the supervision of the Editors with the assistance
of the Series Advisory Board and are selected to maintain the
integrity of the symposia; however, verbatim reproductions of
previously published papers are not accepted. Both reviews
and reports of research are acceptable since symposia may
embrace both types of presentation.
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
PREFACE
R.ECENT ADVANCES IN PESTICIDE FORMULATION TECHNOLOGY were pre
sented at the symposium upon which this book is based. The symposium was
organized to inform industrial, university and government pesticide
researchers and pesticide program administrators about these advances. I
think it is safe to say that most pesticide researchers now realize that the
understanding of the physical chemical principle which pesticid
formulation science is base
pesticide product as understanding pesticide chemical structure-biological
activity relationships.
This book will be particularly useful to researchers working in the area
of pesticide product development. It is hoped that the papers presented
herein will serve to update these researchers on new formulation techniques
as well as to act as catalysts for the development of new product develop
ment concepts.
The first chapter of the book is an overview of the most active pesticide
formulation research areas, including comments on topics not covered in the
symposium because of time limitations. The subsequent chapters deal in
depth with the main topics (Flowables, Computer Applications, and Con
trolled Release Formulations) and general topics. I feel this book fulfills a
very important need—the enhancement of communication among pesticide
formulators and between pesticide formulators and the rest of the pesticide
community.
HERBERT B. SCHER
Deguigne Technical Center
Stauffer Chemical Company
Richmond, California
January 1984
ix
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
1
Advances in Pesticide Formulation Technology
An Overview
HERBERT B. SCHER
Stauffer Chemical Company, Richmond, CA 94804
Pesticide formulation science is a very broad field because it
must deal with formulation development, production and storage
(1-4) as well as the interaction of the pesticide with plants,
insects, mammals, soil (5)
can be classified into
˙ Aqueous Solutions
˙ Emulsifiable Concentrates
˙ Dispersion Concentrates (Aqueous and Nonaqueous
Flowables)
˙
Wettable Powders
˙ Dry Flowables (Water Dispersible Granules)
˙ Granules
˙ Controlled Release
˙ Others (Dusts, Aerosols, etc.)
The factors which influence the choice of formulation are
pesticide physical properties (melting point, solubility,
volatility), pesticide chemical properties (hydrolytic stability,
thermal stability), soil application vs. foliar application, crop
and cultural practice, pesticide biological properties (crop
selectivity, transport), and economics.
This book is a collection of papers concentrating on pesti
cide formulation topics which are currently receiving the greatest
attention and where the greatest advances are being made. These
topics are listed below and make up the four sections of the book.
The number of papers in each section is given in parenthesis.
0097-6156/ 84/0254-0001 $06.00/ 0
© 1984 American Chemical Society
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
2 ADVANCES IN PESTICIDE FORMULATION TECHNOLOGY
Flowable Preparation and Stabilization [4]
Use of Computers for Evaluation and Optimization
of Formulations [4]
Controlled Release Formulations \$]
Selected General Formulation Topics Jo]
Introductory remarks for each of these sections will follow.
I have also added a fifth section to this overview in order to
list and briefly discuss timely pesticide formulation topics
which because of time limitations could not be included in the
symposium program. Important references are listed for each of
these five sections.
Flowable Preparation an
If the technical pesticide has inherent physical properties (high
melting point, friable crystal, low solubility and high chemical
stability in continuous phase) that allow the development of a
flowable formulation, many use advantages can be gained. Flowable
formulations are easy to measure and are not dusty. In addition
since the flowable formulation is a predispersed system, good
dispersibility upon dilution can be readily achieved. Aqueous
based flowables contain no organic solvents and hence have high
flash points and reduced toxicity and phytotoxicity. Water
soluble or water dispersible adjuvants such as film forming agents
can be added directly to aqueous based flowables. These film
forming agents are used to improve adhesion on foliage and to
provide controlled release. Oil based flowables where a liquid
pesticide or inert oil comprises the continuous phase and an
insoluble solid pesticide comprises the dispersed phase are also
receiving attention these days. Flowable formulations also afford
the opportunity to optimize biological activity and physical
stability by varying pesticide particle size and shape.
As described in the previous paragraph, flowable formulations
offer many advantages. However i t is in the area of flowable pre
paration and stabilization where problems can arise and where
extensive testing must take place to assure high formulation
quality. The type of dispersing and milling equipment and type
and concentration of wetting agents, dispersing agents, suspending
agents, film forming agents and freezing point depressants must be
chosen carefully to optimize biological and physical stability.
As will be seen in the second section, computer techniques are
very useful in this optimization process. Rheological measurements
are used to predict physical stability, and accelerated and long
term storage tests are used to confirm physical stability. There
are four papers in this section which deal with these topics. The
papers by Knowles et al. and Warrington et al. deal with novel
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.
1. SCHER An Overview 3
suspension systems and the prediction of stability using rheo-
logical measurements. The papers by Fraley and Dombrowski deal
with dispersing and milling equipment. The paper by Glatzhofer
forms a bridge between this section (Flowables) and the second
section (Computer Applications). Glatzhofer describes a system
where a computer is coupled to a viscometer. He uses this system
to evaluate flowable formulations after accelerated and long term
storage.
One topic which is not covered in this section is the pre
paration and stabilization of emulsion type flowables (oil in
water flowables ) (7). This type of flcwable is just beginning
to receive widespread attention and is still very much in the
experimental stage. In addition to the other factors considered
above, factors which influence oil droplet coalesence, such as
interfacial free energy, electrostatic stabilization and steric
stabilization, must b
type flowable.
Use of Computers for Evaluation and Optimization of Formulations
Computers are being used very effectively for evaluation and
optimization of pesticide formulations. Computer assisted opti
mization of formulation physical and biological properties and
cost (responses) vs. type and concentration of ingredients (in
dependent variables) can be divided into three parts.
1. Experimental Design and Collection of Data (8) -
Statistics are utilized to efficiently sample experi
mental space.
2. Correlate Experimental Data by Regression Analysis (9)-
Statistics are utilized to measure the degree of cor
relation between responses and independent variables.
Important independent variables are identified.
3. Optimize Physical and Biological Properties and Cost
(10) - Construct response surfaces and choose a set of
independent variables to optimize responses. Since each
response may not be optimized by the same set of in
dependent variables, compromises may have to be made
which reflect the relative importance of the responses.
In addition to utilizing computers to optimize pesticide for
mulations, computer programs can be designed to operate equipment
used to evaluate pesticide formulations and to perform complex
theoretical calculations used to guide choice of ingredients.
Of course, computers can also be used for formulation data storage
and acquisition. There are four papers in this section which deal
with these topics. Papers by Botts and Mookerjee describe the
theory and programs associated with experimental design, correla
tion and optimization. Both authors work through actual problems.
In Advances in Pesticide Formulation Technology; Scher, H.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1984.