Electron Beam (EB)
Electron beam (EB) accelerator.
Electron Beam is part of the ionizing energies. These include:
– Electron accelerators (EBeam)
– Very high energy electron accelerators supplying X-rays
Gamma rays (from radioactive isotopes)
Ionization means adding or removing ionized particles (electrons).
– When two atoms are close together, they can exchange or share electrons to form new molecules.
– Ionization is a chemical and non-radioactive process.
Electron emission is achieved by heating a cathode placed in a vacuum chamber.
The electrons are accelerated by a high voltage, between 80 and 300 kV, and are then passed through a thin titanium sheet called the emission window, which separates the vacuum chamber from the irradiation chamber.
The vacuum and irradiation chamber is enclosed in a self-shielded enclosure based of stainless steel and lead to reduce potential x-rays radiationleakage to extremely low level.
Advantages of Electron Beam process.
In the coating, glue and adhesive industries, the EB process can be used for the curing or the polymerization:
– Without heating, which eliminates the problem associated to high temperatures and needs for cooling
– With dry solids formulations, without solvents or photoinitiators
– Considerably reduce energy consumption
– Instant cure,
– Improves gloss, abrasion resistance, adhesion to substrate, etc.
– In the food sector, the EB process can be used for decontamination. The electrons break down the DNA of parasitic cells such as bacteria and considerably increase the shelf life of the irradiated products.
The entire process is completed in the time it takes for the product to pass through the electron beam. EB equipment is powerful enough to cure at speeds above 500 mpm. At these speeds, the whole process takes only 0.024 seconds!
Minimum space in a line:
EB equipment can be very short because curing occurs instantaneously. The total EB unit length is in general less than 3 meters.
No solvents, no VOCs:
Solvents are not used in coatings. Unlike conventional coatings, this process does not require the removal of solvents to create a dry product. In other words, all the chemicals in the “wet” product remain in the “dry” product. This is why no VOCs are produced. No incinerator or other device is needed to treat the pollution.
High electrical efficiency:
The EB curing process is very efficient. The electrical energy is transferred directly into the coatings by the electrons, unlike heat from a large volume of air which must first be heated before it can transfer to the product. EB equipment can be up to 100 times more efficient than thermal furnaces. Energy cost is therefore considerably reduced.
No heating the substrate:
Because the electrical energy goes directly into the product, the substrate generally heats less than a few degrees.
Functional and esthetic characteristics:
High gloss, abrasion resistance, full range of colors and strong adhesion to the substrate are some of the known properties of electron beam cured coatings.