Radiation technology for polymers

195 Pages·2003·4.99 MB·English

by  Jiri George Drobny

Radiation
Technology
for
Polymers
Jiri George Drobny
CRC PR ESS
Boca Raton London New York Washington, D.C.
© 2003 by CRC Press LLC
TX087_frame_book Page 4 Thursday, October 24, 2002 3:53 PM
Library of Congress Cataloging-in-Publication Data
Drobny, Jiri George
Radiation technology for polymers / J. George Drobny
p. cm.
Includes bibliographical references and index.
ISBN 1-58716-108-7 (alk. paper)
1. Radiation curing. 2. Radiation--Industrial applications. 3.
Ultraviolet radiation--Industrial applications. 4. Plastic coating. I. Title.
TP156.C8 D76 2002
668.9—dc20 2002074164
This book contains information obtained from authentic and highly regarded sources. Reprinted material
is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable
efforts have been made to publish reliable data and information, but the author and the publisher cannot
assume responsibility for the validity of all materials or for the consequences of their use.
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No claim to original U.S. Government works
International Standard Book Number 1-58716-108-7
Library of Congress Card Number 2002074164
Printed in the United States of America 1 2 3 4 5 6 7 8 9 0
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© 2003 by CRC Press LLC
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Dedication
To the memory of my parents and my Aunt Anna
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Preface
The industrial use of ultraviolet (UV) and electron beam (EB) radiation is growing
at a fast pace and penetrating many areas such as electronics, printing, packaging,
etc., which traditionally have had their own well established processes. Information
on this topic useful to a professional can be found in many places, such as encyclo-
pedias (Encyclopedia of Polymer Science and Engineering, Ullmann’s Encyclopedia
of Industrial Chemistry), professional publications (PCI, Paint and Coating Industry,
Paint & Powder, FLEXO, Converting, Modern Plastics, Rubber Chemistry and
Technology, Modern Plastics, Wire and Cable, Radiation Physics and Chemistry,
Journal of Applied Polymer Science) and others. RadTech News, a publication of
RadTech North America, covers applications, new technology and industry news.
During the past few years, several very informative books, published by SITA
Technology Ltd. in the U.K., have covered different aspects of UV/EB radiation
technology in great detail. However, because seeking specific information may be
prohibitively time consuming, the need for a quick reference book is obvious.
Radiation Technology of Polymers is designed to meet this need by providing
systematic fundamental information about practical aspects of UV/EB radiation to
professionals in many different fields. The intended audiences are mainly chemists
or chemical engineers who are new to UV/EB radiation technology. Another reader
of this book may be a product or process designer looking for specifics about the
effects of UV/EB on a specific polymeric material or for a potential technological
tool. This book might also be a useful resource for recent college and university
graduates or for graduate or undergraduate students in polymer science and engi-
neering, and for corporate training. Because of the breadth of the field and the
multitude of applications, the book does not go into details; this is left to publications
of a much larger size and scope and to professional periodicals. Rather, it covers
the essentials and points the reader toward sources of more specific or detailed
information. Radiation Technology of Polymers is not intended to compete with other
books on the subject, it merely complements them.
With this in mind, this book is divided into 11 separate chapters, covering the
principles of generating UV and EB energy, equipment, processes, applications,
dosimetry, safety and hygiene. The last chapter covers the newest developments and
trends.
The book began as lectures and seminars at the Plastics Engineering Department
of the University of Massachusetts at Lowell and to varied professional groups and
companies in the United States and abroad. It draws from the author’s more than
40 years of experience as a research and development (R&D) and manufacturing
professional in the polymer processing industry and, more recently, as an indepen-
dent international consultant.
© 2003 by CRC Press LLC
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Acknowledgments
My thanks are due to the team from CRC press — Susan Farmer, Helena
Redshaw and Sylvia Wood — for helping to bring this work to fruition. Thanks also
to Dr. Ewa Andrzejewska, John Chrusciel, Dr. Joseph Koleske and Richard Stowe
for valuable comments and recommendations during the preparation of the manu-
script, and to my family for continuing support and patience. Credit must also be
given to Mr. and Mrs. Gami for the preparation of some of the illustrations.
Merrimack, New Hampshire,
April 2002
© 2003 by CRC Press LLC
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Author
Jiri George Drobny, a native of the Czech Republic,
was educated at the Technical University in Prague in
Chemical Engineering specializing in processing of
plastics and elastomers, and at the Institute of Polymer
Science of the University of Akron in Physics and
Engineering of Polymers. He also earned an MBA in
Finance and Management at Shippensburg State Uni-
versity in Shippensburg, Pennsylvania. His entire
career has been in the polymer processing industry in
Europe, the United States and Canada, mainly in R&D
and manufacturing services with senior and executive
responsibilities. Currently, he is president of Drobny
Polymer Associates, an international consulting firm
specializing in fluoropolymer science and technology,
polymeric composites, radiation processing and elastomer technology. Mr. Drobny
is also active as an educator, author and technical and scientific translator. He is a
member of the Association of Consulting Chemists and Chemical Engineers, Society
of Plastic Engineers, RadTech International, American Chemical Society and
SAMPE and is listed in Who’s Who in America, Who’s Who in Science and Engi-
neering and Who’s Who in the East. He resides in New Hampshire.
© 2003 by CRC Press LLC
Contents
Chapter 1 Introduction
1.1 Basic Concepts
References
Chapter 2 Producing UV and EB Energy
2.1 UV Energy and its Properties
2.1.1 Light Emission from Mercury Gas Discharge
2.1.2 Light Emission from a Microwave Excited Discharge
2.1.3 Generation of Monochromatic UV Radiation
2.2 Electron Beam Energy and Its Properties
References
Chapter 3 Ultraviolet and Electron Beam Curing Equipment
3.1 UV Curing Equipment
3.1.1 Lamps
3.1.1.1 Medium-Pressure Arc Lamps
3.1.1.2 Electrodeless Lamps
3.1.1.3 Low-Pressure Mercury Lamps
3.1.1.4 High-Pressure Mercury Lamps
3.1.1.5 Excimer Lamps
3.1.1.6 Xenon Lamps
3.1.2 Lamp Housing
3.1.3 Power Supply and Control Systems
3.1.3.1 Power Supply Systems
3.1.3.2 Control Systems
3.2 Electron Beam Curing Equipment
3.2.1 Particle Accelerators
3.2.1.1 Direct Accelerators
3.2.1.2 Indirect Accelerators
3.2.1.3 Low-Energy Electron Accelerators
3.2.2 Recent Trends in Development of Electron Beam Curing
Equipment and Technology
References
© 2003 by CRC Press LLC
Chapter 4 Ultraviolet Radiation Processes
4.1 Basic Concepts
4.2 Photoinitiators and Photosensitizers
4.2.1 Free Radical Photonitiators
4.2.1.1 Type I Photoinitiators
4.2.1.2 Type II Photoinitiators
4.2.2 Cationic Photoinitiators
4.2.3 Anionic Photoinitiators
4.2.4 Oxygen Inhibition of Cure
4.2.5 Initiation of UV Hybrid Curing
4.3 Kinetics of Photoinitiated Reactions
4.3.1 Kinetics of Free Radical Photopolymerization
4.3.2 Kinetics of Cationic Photopolymerization
4.4 Chemical Systems in UV Processing
4.4.1 Free Radical-Initiated Systems
4.4.1.1 Acrylate/Methacrylate Systems
4.4.1.2 Styrene/Unsaturated Polyesters
4.4.1.3 Vinyl Ether/Unsaturated Esters
4.4.1.4 Thiol-ene Systems
4.4.1.5 Donor-Acceptor Complexes
4.4.2 Cationic Systems
4.5 Photocross-linking of Polymers
References
Chapter 5 Electron Beam Processes
5.1 Radiation Cross-link Promoters
5.1.1 Indirect Cross-link Promoters
5.1.1.1 Halogenated Compounds
5.1.1.2 Nitrous Oxide
5.1.1.3 Sulfur Monochloride
5.1.1.4 Bases
5.1.2 Direct Cross-link Promoters
5.1.2.1 Maleimides
5.1.2.2 Thiols (Polymercaptans)
5.1.2.3 Acrylic and Allylic Compounds.
5.2 Retardants of Radiation Cross-Linking
5.3 Electron Beam Processing of Plastics
5.3.1 Polyolefins
5.3.1.1 Polyethylene
5.3.1.2 Polypropylene
5.3.2 Polystyrene
5.3.3 Polyvinyl Chloride75
5.3.4 Polymethacrylates and Polyacrylates75
5.3.5 Polyamides
© 2003 by CRC Press LLC
5.3.6 Polyesters
5.3.7 Fluoroplastics
5.3.7.1 Polytetrafluoroethylene
5.3.7.2 FEP
5.3.7.3 Other Fluoroplastics
5.4 Electron Beam Processing of Elastomers
5.4.1 Physical Properties of Radiation Cross-linked Elastomers
5.4.2 Effects of Radiation on Individual Elastomers
5.4.2.1 Natural Rubber and Synthetic Polyisoprene
5.4.2.2 Polybutadiene and Its Copolymers
5.4.2.3 Polyisobutylene and Its Copolymers
5.4.2.4 Ethylene-Propylene Copolymers and Terpolymers
5.4.2.5 Polychloroprene
5.4.2.6 Silicone Elastomers
5.4.2.7 Fluorocarbon Elastomers
5.4.2.8 Fluorosilicone Elastomers
5.5 Electron Beam Processing of Liquid Systems
5.6 Grafting and Other Polymer Modifications
5.6.1 Grafting
5.6.2 Other Polymer Modifications
References
Chapter 6 Coating Methods Used in UV and EB Technology
6.1 Roll Coating
6.1.1 Direct Roll Coating
6.1.2 Reverse Roll Coating
6.2 Curtain Coating
6.3 Spray Application
6.3.1 Compressed Air Gun Spraying
6.3.2 Airless Gun Spraying
6.4 Dip Coating
6.5 Flow Coating
6.6 Spin Coating
6.7 Rod Coating
References
Chapter 7 Applications of UV Radiation
7.1 UV Curing of Coatings and Paints
7.1.1 Functional and Decorative Coatings
7.1.1.1 Coatings on Flat, Rigid Substrates
7.1.1.2 UV Curing of Coatings on Flexible Substrates
7.1.2 UV Curing of Lacquers, Varnishes and Paints
7.1.3 Three-Dimensional Curing
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7.1.4 UV Curing of Coatings and Inks on Cylindrical Parts
7.1.5 UV Matting of Coatings
7.2 UV Curing of Adhesives
7.3 UV-Cured Silicone Release Coatings
7.4 Spot Curing
7.5 UV Curing in Printing and Graphic Arts
7.5.1 Screen Printing
7.5.2 Flexography
7.5.3 Letterpress and Offset Letterpress (Dry Offset)
7.5.4 Lithography
7.5.5 Rotogravure Printing
7.6 Rapid Prototyping
7.7 UV Powder Coatings
7.7.1 The Chemistry of UV-Curable Powders
7.7.2 Material and Substrate Preparation
7.7.3 Powder Coating Application
7.7.4 Substrates Suitable for UV Powder Coating
7.7.4.1 Plastics
7.7.4.2 Wood and Wood Composites
7.7.4.3 Preassembled Parts
7.7.4.4 Large-Mass Parts
7.7.5 Applications
7.8 Other Applications for UV Curing
7.8.1 Electronics
7.8.2 Optical Components and Optoelectronic Applications
7.8.2.1 Optical Fibers
7.8.2.2 Other Optical and Optoelectronic Applications
7.9 Production of Composites
7.9.1 Dental Applications
7.9.2 Other Composite Applications
Chapter 8 Applications of Electron Beam Radiation
8.1 EB Processing in the Wire and Cable Technology
8.1.1 Equipment and Process
8.1.2 Recent Developments and Trends
8.2 EB Processing in Tire Technology
8.3 EB Processing in the Manufacture of Polyolefin Foams
8.3.1 Foam Expansion and Its Control
8.3.2 Manufacturing Processes
8.3.3 Comparison of Chemical and Radiation Processes
8.4 EB Processing in the Production of Heat-Shrinkable Materials
8.4.1 Heat-Shrinkable Tubing
8.4.2 Heat-Shrinkable Sheets and Films
8.5 EB Processing in Coatings, Adhesives, Paints and Printing Inks
8.5.1 Magnetic Media
© 2003 by CRC Press LLC