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Radiation curing - an overview
0146-5724/90 $3.00 + 0.00 Pergamon Press plc
Radiat. Phys. Chem. Vol. 35, Nos I-3, pp. 30-35, 1990 Int. ,1. Radiat. Appl. Instrum., Part C Printed in Great Britain
RADIATION
CURING
- AN
OVERVIEW
Urs V. L~uppi
betacon sa P.O.Box 278 C H - 1 2 6 1 L a Rippe, Switzerland
ABSTRACT Radiation curing is a term used to describe the rapid conversion of especially formulated solvent free liquids to solids by ultra violet (UV) or electron beam (EB) radiation. The paper concentrates on EB. A discussion of the major differences between UV and EB is followed by a listing of industrial low energy electron beam curing applications and an analysis of past and future developments.
KEYWORDS Electron beam, curing,
EB
curing,
radiation
curing,
radiation
processing,
polymerization,
UV
INTRODUCTION The term "radiation curing" is generally used to describe the instant polymerization of a liquid chemical media, usually solvent free, by either ultra-violet (UV) or electron beam (EB) radiation. When conventional thermal methods are applied the words "drying" or "hardening" are used (of a lacquer, a coating, a varnish, an ink or an adhesive). At the RadTech '88 Conference in New Orleans the Radiation Curing Association, RadTech International, defined the process as follows (RadTech North America). "The use of electron beam or ultra-violet radiation as an energy source to induce the rapid conversion of especially formulated 100% reactive liquids to solids." Radiation curing finds increasing use due to its unique characteristics. The equipment used, often called a cold oven, allows the manufacturing of products which can not be made by thermal methods due to the temperatures involved. New product qualities, for instance better mechanical characteristics and higher gloss can be made at increased production speeds and lower energy consumption. As additional "free" advantage the users no longer need to install expensive plants for the elimination of pollutants. The chemistry used for radiation curing processes does not contain solvents; it is a 100% solids chemistry. The amount of chemistry deposited on substrates remains on it, nothing leaves the substrate by evaporation. Radiation curing is used for a variety of industrial manufacturing processes. Over 99% of all installations are UV systems used to cure printing inks in screen-, label-, offsetand other printing applications, overprint varnishes, wood coatings, coatings on metal and plastic substrates, adhesives and varnishes in the automotive and electronics industries and for many other applications. Industry specialists estimate that I0"000 to 15'000 (or more) UV units are in industrial use today world-wide (Hermanns, Jung, Klamann 1989). This paper concentrates on electron beam curing, or, expressed differently, on less than 1% of the radiation curing units used by the industry. 1% does not seem to be much but it represents 127 low energy electron beam production machines in the energy range of 150 kV to 300 kV used for curing applications as defined above. Including laboratory and pilot units, a total of 280 EB accelerators for curing applications have been sold until the end of March 1989, Table I, (IMRP6, 1987). Not included in this figure are machines installed in the USSR and in China. Before discussing electron beam equipment and applications, the major differences between UV and EB are briefly summarized in the next part. 30
7th International Meeting on Radiation Processing
31
UV and EB. The Major Differences UV curing is generally used for clear or only lightly pigmented coatings and inks which stay on the surface of a substrate material. Heavy pigmented coatings like black or a full white colors, can, if at all, only slowly be cured h y U V . The black absorbs the UV light, the white, containing Titanium-Oxyde reflects the UV light. UV rays can not reach chemistry which penetrated into a substrate. Uncured chemistries remain liquid and pose a health hazard in subsequent manufacturing processes or when the product is put on the market and into the hands of consumers. UV coatings and inks must contain photo-initiators. They are necessary to initiate the polymerization process, the UV rays themselves are not energetic enough. The photo-initiator makes an UV chemistry often more expensive, it can also cause a strong odor. 100% cured restriction products).
coatings for its
can use
not be obtained with UV, a disadvantage of the technology and a in food related applications (food packagings and similar
Electrons are more powerfull, they arrive at the surface of a chemistry to be cured at nearly the speed of light and with energies, depending on the application, between 150 keV and 300 keV. Electrons are not hindered by pigmentation; for electron beam curing there are no color limitations. Electrons reach coatings hurried inside a paper or an other substrate, they can cure an adhesive between two opaque layers (i. e. aluminum foil) and electrons have the capability to cure a coating, ink or adhesive for 100%, thus making the process suitable for critical applications where a 100% cured chemistry is an absolute must. There exist also economical differences: - Production speeds are generally higher with EB. All electron beam curing applications require the inerting of the curing or processing zone. EB curable chemistries are oxygen inhibited when cured in air, the surface of the coatings remain sticky and uncured. Most UV chemistries cure in air. An exception are the more recent UV silicone release coatings and the so called Dual-Cure(R) systems used in wood panel coating. Last but not least, UV lamps are considerably less expensive than EB systems. Electron beam processors can be 2 to 20 times more expensive than an UV system of the same width and capacity. Very seldom, but not impossible are applications where an UV system costs as much as an EB system for doing the same job. The question which system to use is always dictated by the economy of a given process. If it is technically leasable with UV, UV is normally the right and only choice as the investment costs are considerably lower. The operating costs are usually, but not always, lower for UV and the UV chemistry is in most cases on the same price level as EB chemistry or only slightly more expensive.
EB Equipmentand Applications Electron Beam Processors, used for curing applications, are typically 50cm to 240cm wide. They are of the non-scanner, multi-filament Broad-Beam (RPC) or linear cathode Electrocurtain (ESI) type. Several installations, especially in Europe, are of the beam scanning type (Polymer Physik and older HVEC, Ford, Sames and BBC installations). Modern electron beam accelerators can generate beam currents up to 1000 mA. Machines with power outputs of 200kW and more are now in industrial use. Low energy electron beam processors are equipped with an integrated lead shielding, called self-shield. They are small and compact and can easily be installed on industrial manufacturing lines. 127 industrial low energy electron beam processors are now used for the radiation curing production applications indicated on the following pages (La~ppi 1987). Table lz
Lab Units Pilot Units Production Units Total
Electron Beam Equipment for Curing Applications Europe 28 21 46 95
Japan 35 6 17 58
Pacific 3 5 8
America 43 17 59 119
32
URs V. L,~uPPI
EB-curing applications March 1989 (in alphabetical order): Anti-static film: - clear coatings with anti-static properties on thin plastic film, used for the packing of sensitive electric and electronic components: USA. Flocked products: - curing of flock adhesive on plastic substrates for shoe components, automotive parts and other end-usest USA. Gypsum tiles: - pigmented high gloss and metallic coatings on glass fibre re-inforced gypsum tiles for interior decoration: Japan. Intaglio (security) printing: - curing of inks on stamps and paper currency: Europe, USA. Laminates: - paper to paper, paper to plastic foil and similar laminates for applications such as credit cards, playing cards and similar products: USA. Magnetic media: - curing of magnetic media coatings on thin plastic film and foil for video tapes and floppy discs: Japan, USA. Metallized paper: - base coating before direct metallization and protective varnish after metallization for labels, cigarette wrap, packagings and gift wrap: Australia, Europe, USA. - adhesive and protective lacquer for full width and selective transfer metallization of paper for labels, decals, luxury packagings, greating cards, gift wrap and similar products (EB-Aluglass): Europe, USA. Metallized film: - tinted and protective coatings on metallized surfaces for emergency blankets, cryo- and aerospace products, solar film: USA. Metal coatings: - pigmented, solvent containing hybrid coatings on steel sheets for household and other appliances, (Ellio Sheet): Japan. Offset (letterpress) printing: - ink and overprint varnish on high-speed web-offset presses for liquid food containers and packaging materials: Australia, Asia, Europe, Japan, North and South-America. - curing of printing inks on plastic sheets in sheet offset printing for advertizing materials, book covers, video casette covers and similar plastic products: Japan. Overprint varnish: - clear overprint varnish in high speed gravure printing for packaging materials: USA. Paper coatings: - high gloss clear and pigmented coatings on paper and paper board for gift wrap and packaging applications, Australia, Europe, USA. - clear and pigmented coatings on paper for the furniture and construction panelling industry: Australia, Europe, USA. Pressure sensitive adhesives (PSA): - on masking tape paper for the automotive industry: Europe. adhesives on plastic decals: Europe, Japan, USA. - peelable, protective film: Japan. -
Silicone Release Coatings: - on paper and plastic film, for decals, labels, packaging and other applications: Australia, Europe, Japan, USA. Telephone cards: - optically clear and scratch resistant coating on PVC telephone card material: Europe.
7th International Meeting on Radiation Processing
33
Wood panels~ - primer and pigmented top coatings for doors and furniture parts. Europe, USA. - laminating adhesive and protective top coat on wood grain printed decor foils for wood panels used in furniture applications~ USA. Wood-Cement panels~ - for interior and outdoor construction panelling use~ Europe. Low energy electrons are also increasingly used for non-curing applications such as the crosslinking of plastic film, tubing and wire insulations (Tripp 89). The first industrial installation in Europe became operational in 1988. In-line sterilization, (Aaronson, Nablo 1987) is an other application area for low energy electrons. The process is commercially used in the USA.
Future Developments The industry is using electron accelerators for the curing of coatings since the early 1970's (L~uppi 1980). The growth of the industry can probably best be measured in number of machines sold, see Figure i. After the first few equipment sales from 1970 to 1972, a first boom took place in the mid 1970's. These machines were almost exclusively sold to manufacturers of wood panels and furniture components. From 1976 on the industry grew quite steadily, with a sharp increase in machine sales in 1982. During these years EB machines were purchased for many different applications. The peak in 1982 includes the magnetic media boom and the first EB machines for web-offset printing. Since 1984 the majority of the electron beam processors for industrial curing applications were purchased for the curing of printing ink on web-offset printing presses. In 1988 a sharp decline in machine sales occured, Figure 2. A market analysis reveales that the decline is due to the near collaps of the market leader, who up to this point enjoyed an average market share of 80%, or an average of 19 industrial EB curing units sold per year, from 1980 to 1987. The market leaders share in EB curing equipment sales decreased to 23% in 1988 whereas its competitors maintained or slightly increased their market shares (betacon 1989). The right term for expressing the present general growth of the industry is "stagnation"l In 1988 and in the first 3 months of 1989 only four machines were sold for other EB-curing applications than web-offset printing. What is wrong? Why this stagnation? Finding the correct answer to these questions is very difficult, if not impossible. One would have to ask the potential users of the technology why they do not buy equipment or why they are not using the technology. Partially responsible for the slowed down development are the EB equipment manufacturers. The quality and reliability of their equipment did often not meet the requirements of the industry. The nature and complexity of the EB-equipment made the manufacturers of these machines often unsensitive for the requirements of the potential users. A paper converter, for instance, is interested in a new dryer and not in a high-tech, exotic piece of electronic "radiation" equipment he can not operate and maintain on a daily basis with his own staff. The equipment improved in the past two years, and more reliable equipment is now available.
microprocessor
controlled,
fully
automatic
Other reasons for the slow-down were the unstable financial situation and often changing ownership of EB equipment manufacturers. Some companies were forced to concentrate their efforts on internal reorganizations and the professional education of new managements instead on the promotion of the technology. For many potential users EB-curing still is an expensive (and exotic) technology. EB-equipment, especially low energy EB-equipment for the every day application in such areas as the graphic arts industry, is too expensive! The price of US S 600'000.- and more for a medium width, medium power electron beam "dryer" for installation in a web-offset printing press is an investment only few, highly specialized printers can Justify for high added-value products. If in addition the customer is not assured that his EB-equipment supplier is still existing in 5 years or more, if the chemistry is available from a few suppliers only and there exist alternatives, the customer often chooses the alternative which is the conventional thermal drying process with solvent incineration or recovery systems. This is what often happened in the past 2 years in EB-curing!
34
URS V. L.~uPPI
Under such conditions was programmed!
the
slow
down of the low energy EB-market for curing applications
But let us look positively into the future. The unstable financial situation of the major makers of EB equipment has improved. They are now all under the wings of larger companies with enough financial strength to support their operations until profits are earned again. The prices of the EB-equipment became a little bit more reasonable and the equipment itself was further developed to meet the requirements of the users. A good example may be the former market leader which is reporting increased machine sales for the first three months of 1989. An other light in the tunnel is the development of EB curing in web-offset printing. This application shows the highest growth rates. All EB curing units sold in 1989, with one exception, will be installed in web-offset printing presses. 30% of all BB curing units ever sold are already used for this application and some specialists are convinced that this is only the beginning of what will become the largest EB application, provided the electron beam accelerators become more dedicated for this application and (much) less expensive.
RadTech International To promote radiation curing and to better serve the needs of the industry concerned, suppliers of chemistry, substrates and equipment, together with users, founded 1986 in the USA the radiation curing association RadTech International. The association is an off-spring of the Radcure activities of the Society of Manufacturing Engeneers's Association of Finishing Processes (AFP/SME). AFP/SME held 1974 its first Radiation Curing Conference in Atlanta, USA, followed by biennial conferences until 1986 when its last, now RadCure called conference, took place in Baltimore, USA. AFP/SME, together with the help of dedicated European equipment manufacturers and suppliers of chemistry was also responsible for the highly successful European RadCure conferences 1983 and 1985 in Lausanne and in Basel (Switzerland) and 1987 in Munich, Western Germany. 1988 RadTech International North-America held its first "own" conference, RadTech '88 in New Orleans, USA. Over 1000 people attended the conference and 62 companies exhibited their products at the RadTech '88 exhibition. Shortly after the conference, RadTech Europe was founded. The European Division of RadTech will have it's first conference and exhibition in fall of this year, from Oct. 9 to 11 in Florence, Italy. Under the theme "Radiation Curing~ A World of Opportunity", RadTech International North America will organize the RadTech '90 Conference and Exhibition from March 25 to 29, 1990 in Chicago, Illinois, USA. End of March 1989 RadTech North-America and Europe had together over 1000 members.
REFERENCES Aaronson J. N. and Nablo S. V. Dr., An In-Line Electron Sterilizer for Container Geometries to 250 ml, IMRP6 1987 Ottawa Canada, Radiation Physics and Chemistry, Voi.31, No's 4-6, 711. Betacon, La Rippe, Switzerland, 1989, Market Analysis: Electron Beam Curing Equipment and Applications. BroadBeam, Trade Mark of Radiation Polymer Corp., RPC, USA Dual-Cure, Trade Mark of Pittsburg Plate Glass, P PG, USA Electrocurtain, Trade Mark of Energy Sciences, Inc., ESI, USA Hermans R., Wallace-Knight, England, Jung J., IST Strahlentechnik Metz, Federal Republik of Germany and Klamann P., Eltosch, Federal Republik of Germany, private communications. IMRP6, Prospects for Industrial Electron Beam Processing, Panel Discussion, beta z~q_ag!ma_
7th International Meeting on Radiation Processing
35
L~uppi, Urs V. (1980). An Overview on Electron Beam Processing in Europe. Pr_ogepdlngs_ Radiation Curing V, Boston 1980, AFP/SME, 27-48 L~uppi, Urs V. (1987). IMRP6 Ottawa, Canada, Success and Prospects for Low Energy, Self-Shielded Electron Beam Accelerators. Radiation Physics and Chemistry[L Vol_ ._3_~i N_OSL_ 1-3, 1988, Pergamon Press, Oxford, England. RadTech '88 North America , Conference and Exhibition, April 24 - 28, 1988, New Orleans, USA Tripp E. P. III, Low Voltage Selfshielded Electron Beam Accelerators Offer New Opportunities, beta-gamma 1/89
30C
200
= 100
71
72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 ACCUMULATED EB CURING EQUIPMENT SALES FRON
1971
UNTIL MARCH
1989
FIGURE 1
t
30
20
•
= TOTAL
10 = USA
\
~.+, " X .
,
{r--.K.=
i ~P
"-~
72 FIGURE 2
1975
o--d
/
X O
1980
ANNUAL EB CURING EQUIPMENT SALES
1985 1972 U N T I L
1989 MARCH 1989
= EUROPE = JAPAN
Radiat. Phys. Chem. Vol. 35, Nos I-3, pp. 30-35, 1990 Int. ,1. Radiat. Appl. Instrum., Part C Printed in Great Britain
RADIATION
CURING
- AN
OVERVIEW
Urs V. L~uppi
betacon sa P.O.Box 278 C H - 1 2 6 1 L a Rippe, Switzerland
ABSTRACT Radiation curing is a term used to describe the rapid conversion of especially formulated solvent free liquids to solids by ultra violet (UV) or electron beam (EB) radiation. The paper concentrates on EB. A discussion of the major differences between UV and EB is followed by a listing of industrial low energy electron beam curing applications and an analysis of past and future developments.
KEYWORDS Electron beam, curing,
EB
curing,
radiation
curing,
radiation
processing,
polymerization,
UV
INTRODUCTION The term "radiation curing" is generally used to describe the instant polymerization of a liquid chemical media, usually solvent free, by either ultra-violet (UV) or electron beam (EB) radiation. When conventional thermal methods are applied the words "drying" or "hardening" are used (of a lacquer, a coating, a varnish, an ink or an adhesive). At the RadTech '88 Conference in New Orleans the Radiation Curing Association, RadTech International, defined the process as follows (RadTech North America). "The use of electron beam or ultra-violet radiation as an energy source to induce the rapid conversion of especially formulated 100% reactive liquids to solids." Radiation curing finds increasing use due to its unique characteristics. The equipment used, often called a cold oven, allows the manufacturing of products which can not be made by thermal methods due to the temperatures involved. New product qualities, for instance better mechanical characteristics and higher gloss can be made at increased production speeds and lower energy consumption. As additional "free" advantage the users no longer need to install expensive plants for the elimination of pollutants. The chemistry used for radiation curing processes does not contain solvents; it is a 100% solids chemistry. The amount of chemistry deposited on substrates remains on it, nothing leaves the substrate by evaporation. Radiation curing is used for a variety of industrial manufacturing processes. Over 99% of all installations are UV systems used to cure printing inks in screen-, label-, offsetand other printing applications, overprint varnishes, wood coatings, coatings on metal and plastic substrates, adhesives and varnishes in the automotive and electronics industries and for many other applications. Industry specialists estimate that I0"000 to 15'000 (or more) UV units are in industrial use today world-wide (Hermanns, Jung, Klamann 1989). This paper concentrates on electron beam curing, or, expressed differently, on less than 1% of the radiation curing units used by the industry. 1% does not seem to be much but it represents 127 low energy electron beam production machines in the energy range of 150 kV to 300 kV used for curing applications as defined above. Including laboratory and pilot units, a total of 280 EB accelerators for curing applications have been sold until the end of March 1989, Table I, (IMRP6, 1987). Not included in this figure are machines installed in the USSR and in China. Before discussing electron beam equipment and applications, the major differences between UV and EB are briefly summarized in the next part. 30
7th International Meeting on Radiation Processing
31
UV and EB. The Major Differences UV curing is generally used for clear or only lightly pigmented coatings and inks which stay on the surface of a substrate material. Heavy pigmented coatings like black or a full white colors, can, if at all, only slowly be cured h y U V . The black absorbs the UV light, the white, containing Titanium-Oxyde reflects the UV light. UV rays can not reach chemistry which penetrated into a substrate. Uncured chemistries remain liquid and pose a health hazard in subsequent manufacturing processes or when the product is put on the market and into the hands of consumers. UV coatings and inks must contain photo-initiators. They are necessary to initiate the polymerization process, the UV rays themselves are not energetic enough. The photo-initiator makes an UV chemistry often more expensive, it can also cause a strong odor. 100% cured restriction products).
coatings for its
can use
not be obtained with UV, a disadvantage of the technology and a in food related applications (food packagings and similar
Electrons are more powerfull, they arrive at the surface of a chemistry to be cured at nearly the speed of light and with energies, depending on the application, between 150 keV and 300 keV. Electrons are not hindered by pigmentation; for electron beam curing there are no color limitations. Electrons reach coatings hurried inside a paper or an other substrate, they can cure an adhesive between two opaque layers (i. e. aluminum foil) and electrons have the capability to cure a coating, ink or adhesive for 100%, thus making the process suitable for critical applications where a 100% cured chemistry is an absolute must. There exist also economical differences: - Production speeds are generally higher with EB. All electron beam curing applications require the inerting of the curing or processing zone. EB curable chemistries are oxygen inhibited when cured in air, the surface of the coatings remain sticky and uncured. Most UV chemistries cure in air. An exception are the more recent UV silicone release coatings and the so called Dual-Cure(R) systems used in wood panel coating. Last but not least, UV lamps are considerably less expensive than EB systems. Electron beam processors can be 2 to 20 times more expensive than an UV system of the same width and capacity. Very seldom, but not impossible are applications where an UV system costs as much as an EB system for doing the same job. The question which system to use is always dictated by the economy of a given process. If it is technically leasable with UV, UV is normally the right and only choice as the investment costs are considerably lower. The operating costs are usually, but not always, lower for UV and the UV chemistry is in most cases on the same price level as EB chemistry or only slightly more expensive.
EB Equipmentand Applications Electron Beam Processors, used for curing applications, are typically 50cm to 240cm wide. They are of the non-scanner, multi-filament Broad-Beam (RPC) or linear cathode Electrocurtain (ESI) type. Several installations, especially in Europe, are of the beam scanning type (Polymer Physik and older HVEC, Ford, Sames and BBC installations). Modern electron beam accelerators can generate beam currents up to 1000 mA. Machines with power outputs of 200kW and more are now in industrial use. Low energy electron beam processors are equipped with an integrated lead shielding, called self-shield. They are small and compact and can easily be installed on industrial manufacturing lines. 127 industrial low energy electron beam processors are now used for the radiation curing production applications indicated on the following pages (La~ppi 1987). Table lz
Lab Units Pilot Units Production Units Total
Electron Beam Equipment for Curing Applications Europe 28 21 46 95
Japan 35 6 17 58
Pacific 3 5 8
America 43 17 59 119
32
URs V. L,~uPPI
EB-curing applications March 1989 (in alphabetical order): Anti-static film: - clear coatings with anti-static properties on thin plastic film, used for the packing of sensitive electric and electronic components: USA. Flocked products: - curing of flock adhesive on plastic substrates for shoe components, automotive parts and other end-usest USA. Gypsum tiles: - pigmented high gloss and metallic coatings on glass fibre re-inforced gypsum tiles for interior decoration: Japan. Intaglio (security) printing: - curing of inks on stamps and paper currency: Europe, USA. Laminates: - paper to paper, paper to plastic foil and similar laminates for applications such as credit cards, playing cards and similar products: USA. Magnetic media: - curing of magnetic media coatings on thin plastic film and foil for video tapes and floppy discs: Japan, USA. Metallized paper: - base coating before direct metallization and protective varnish after metallization for labels, cigarette wrap, packagings and gift wrap: Australia, Europe, USA. - adhesive and protective lacquer for full width and selective transfer metallization of paper for labels, decals, luxury packagings, greating cards, gift wrap and similar products (EB-Aluglass): Europe, USA. Metallized film: - tinted and protective coatings on metallized surfaces for emergency blankets, cryo- and aerospace products, solar film: USA. Metal coatings: - pigmented, solvent containing hybrid coatings on steel sheets for household and other appliances, (Ellio Sheet): Japan. Offset (letterpress) printing: - ink and overprint varnish on high-speed web-offset presses for liquid food containers and packaging materials: Australia, Asia, Europe, Japan, North and South-America. - curing of printing inks on plastic sheets in sheet offset printing for advertizing materials, book covers, video casette covers and similar plastic products: Japan. Overprint varnish: - clear overprint varnish in high speed gravure printing for packaging materials: USA. Paper coatings: - high gloss clear and pigmented coatings on paper and paper board for gift wrap and packaging applications, Australia, Europe, USA. - clear and pigmented coatings on paper for the furniture and construction panelling industry: Australia, Europe, USA. Pressure sensitive adhesives (PSA): - on masking tape paper for the automotive industry: Europe. adhesives on plastic decals: Europe, Japan, USA. - peelable, protective film: Japan. -
Silicone Release Coatings: - on paper and plastic film, for decals, labels, packaging and other applications: Australia, Europe, Japan, USA. Telephone cards: - optically clear and scratch resistant coating on PVC telephone card material: Europe.
7th International Meeting on Radiation Processing
33
Wood panels~ - primer and pigmented top coatings for doors and furniture parts. Europe, USA. - laminating adhesive and protective top coat on wood grain printed decor foils for wood panels used in furniture applications~ USA. Wood-Cement panels~ - for interior and outdoor construction panelling use~ Europe. Low energy electrons are also increasingly used for non-curing applications such as the crosslinking of plastic film, tubing and wire insulations (Tripp 89). The first industrial installation in Europe became operational in 1988. In-line sterilization, (Aaronson, Nablo 1987) is an other application area for low energy electrons. The process is commercially used in the USA.
Future Developments The industry is using electron accelerators for the curing of coatings since the early 1970's (L~uppi 1980). The growth of the industry can probably best be measured in number of machines sold, see Figure i. After the first few equipment sales from 1970 to 1972, a first boom took place in the mid 1970's. These machines were almost exclusively sold to manufacturers of wood panels and furniture components. From 1976 on the industry grew quite steadily, with a sharp increase in machine sales in 1982. During these years EB machines were purchased for many different applications. The peak in 1982 includes the magnetic media boom and the first EB machines for web-offset printing. Since 1984 the majority of the electron beam processors for industrial curing applications were purchased for the curing of printing ink on web-offset printing presses. In 1988 a sharp decline in machine sales occured, Figure 2. A market analysis reveales that the decline is due to the near collaps of the market leader, who up to this point enjoyed an average market share of 80%, or an average of 19 industrial EB curing units sold per year, from 1980 to 1987. The market leaders share in EB curing equipment sales decreased to 23% in 1988 whereas its competitors maintained or slightly increased their market shares (betacon 1989). The right term for expressing the present general growth of the industry is "stagnation"l In 1988 and in the first 3 months of 1989 only four machines were sold for other EB-curing applications than web-offset printing. What is wrong? Why this stagnation? Finding the correct answer to these questions is very difficult, if not impossible. One would have to ask the potential users of the technology why they do not buy equipment or why they are not using the technology. Partially responsible for the slowed down development are the EB equipment manufacturers. The quality and reliability of their equipment did often not meet the requirements of the industry. The nature and complexity of the EB-equipment made the manufacturers of these machines often unsensitive for the requirements of the potential users. A paper converter, for instance, is interested in a new dryer and not in a high-tech, exotic piece of electronic "radiation" equipment he can not operate and maintain on a daily basis with his own staff. The equipment improved in the past two years, and more reliable equipment is now available.
microprocessor
controlled,
fully
automatic
Other reasons for the slow-down were the unstable financial situation and often changing ownership of EB equipment manufacturers. Some companies were forced to concentrate their efforts on internal reorganizations and the professional education of new managements instead on the promotion of the technology. For many potential users EB-curing still is an expensive (and exotic) technology. EB-equipment, especially low energy EB-equipment for the every day application in such areas as the graphic arts industry, is too expensive! The price of US S 600'000.- and more for a medium width, medium power electron beam "dryer" for installation in a web-offset printing press is an investment only few, highly specialized printers can Justify for high added-value products. If in addition the customer is not assured that his EB-equipment supplier is still existing in 5 years or more, if the chemistry is available from a few suppliers only and there exist alternatives, the customer often chooses the alternative which is the conventional thermal drying process with solvent incineration or recovery systems. This is what often happened in the past 2 years in EB-curing!
34
URS V. L.~uPPI
Under such conditions was programmed!
the
slow
down of the low energy EB-market for curing applications
But let us look positively into the future. The unstable financial situation of the major makers of EB equipment has improved. They are now all under the wings of larger companies with enough financial strength to support their operations until profits are earned again. The prices of the EB-equipment became a little bit more reasonable and the equipment itself was further developed to meet the requirements of the users. A good example may be the former market leader which is reporting increased machine sales for the first three months of 1989. An other light in the tunnel is the development of EB curing in web-offset printing. This application shows the highest growth rates. All EB curing units sold in 1989, with one exception, will be installed in web-offset printing presses. 30% of all BB curing units ever sold are already used for this application and some specialists are convinced that this is only the beginning of what will become the largest EB application, provided the electron beam accelerators become more dedicated for this application and (much) less expensive.
RadTech International To promote radiation curing and to better serve the needs of the industry concerned, suppliers of chemistry, substrates and equipment, together with users, founded 1986 in the USA the radiation curing association RadTech International. The association is an off-spring of the Radcure activities of the Society of Manufacturing Engeneers's Association of Finishing Processes (AFP/SME). AFP/SME held 1974 its first Radiation Curing Conference in Atlanta, USA, followed by biennial conferences until 1986 when its last, now RadCure called conference, took place in Baltimore, USA. AFP/SME, together with the help of dedicated European equipment manufacturers and suppliers of chemistry was also responsible for the highly successful European RadCure conferences 1983 and 1985 in Lausanne and in Basel (Switzerland) and 1987 in Munich, Western Germany. 1988 RadTech International North-America held its first "own" conference, RadTech '88 in New Orleans, USA. Over 1000 people attended the conference and 62 companies exhibited their products at the RadTech '88 exhibition. Shortly after the conference, RadTech Europe was founded. The European Division of RadTech will have it's first conference and exhibition in fall of this year, from Oct. 9 to 11 in Florence, Italy. Under the theme "Radiation Curing~ A World of Opportunity", RadTech International North America will organize the RadTech '90 Conference and Exhibition from March 25 to 29, 1990 in Chicago, Illinois, USA. End of March 1989 RadTech North-America and Europe had together over 1000 members.
REFERENCES Aaronson J. N. and Nablo S. V. Dr., An In-Line Electron Sterilizer for Container Geometries to 250 ml, IMRP6 1987 Ottawa Canada, Radiation Physics and Chemistry, Voi.31, No's 4-6, 711. Betacon, La Rippe, Switzerland, 1989, Market Analysis: Electron Beam Curing Equipment and Applications. BroadBeam, Trade Mark of Radiation Polymer Corp., RPC, USA Dual-Cure, Trade Mark of Pittsburg Plate Glass, P PG, USA Electrocurtain, Trade Mark of Energy Sciences, Inc., ESI, USA Hermans R., Wallace-Knight, England, Jung J., IST Strahlentechnik Metz, Federal Republik of Germany and Klamann P., Eltosch, Federal Republik of Germany, private communications. IMRP6, Prospects for Industrial Electron Beam Processing, Panel Discussion, beta z~q_ag!ma_
7th International Meeting on Radiation Processing
35
L~uppi, Urs V. (1980). An Overview on Electron Beam Processing in Europe. Pr_ogepdlngs_ Radiation Curing V, Boston 1980, AFP/SME, 27-48 L~uppi, Urs V. (1987). IMRP6 Ottawa, Canada, Success and Prospects for Low Energy, Self-Shielded Electron Beam Accelerators. Radiation Physics and Chemistry[L Vol_ ._3_~i N_OSL_ 1-3, 1988, Pergamon Press, Oxford, England. RadTech '88 North America , Conference and Exhibition, April 24 - 28, 1988, New Orleans, USA Tripp E. P. III, Low Voltage Selfshielded Electron Beam Accelerators Offer New Opportunities, beta-gamma 1/89
30C
200
= 100
71
72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 ACCUMULATED EB CURING EQUIPMENT SALES FRON
1971
UNTIL MARCH
1989
FIGURE 1
t
30
20
•
= TOTAL
10 = USA
\
~.+, " X .
,
{r--.K.=
i ~P
"-~
72 FIGURE 2
1975
o--d
/
X O
1980
ANNUAL EB CURING EQUIPMENT SALES
1985 1972 U N T I L
1989 MARCH 1989
= EUROPE = JAPAN