EB for non-thermal
Crosslinking/Vulcanisation of coatings
Considering that some years ago solvent free systems savings in
energy or low space requirements were the main arguments in favour of irradiation of
surfaces to dry lacquer with low-energy electrons come to the fore:
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High scuff resistant coatings |
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Controlled, calculable, through-curing |
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Immediate stacking or subsequent
treatment of the materials |
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High flow rate, substantial increase in
production speed in comparison to heat treatment methods |
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Constant product quality, precise
maintain crosslinking and vulcanising process conditions through very high dose precision
over working width, depth of material and production time |
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Considerably lower extraction values
compared to UV-curing, processing without photoinitiators |
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Acceptable costs at appropriate
quantities |
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Minimal temperature increase through
radiation process; therefore no migration of low boiling components from the coating
material. No change of moisture level in the substrate. |
Today electron-beam curing (non-thermal curing) in used industrially
for the surface technology in the following fields:
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Curing of pigmented lacquers on doors |
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All-around curing of lacquers on
mouldings |
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Controlled through-curing of coatings on
finished parquet |
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High scuff-resistant floor-coverings |
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Production of high-gloss surface in the
board industry |
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Curing of coatings on furniture foils
(lacquer from the roll) |
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Crosslinking of Lacquer on top of papers
for the production of HPL (high-pressure Laminate) - and CPL (Continuos-Pressure
Laminate)-material with lacquered surface |
|
Curing of coating on boards with
UV-/EB-curing processes |
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Even Crosslinking of pressure-sensitive
adhesive masses (Tesakrepp-material) to increase temperature stability |
|
Drying of printing inks |
Controlled, calculable through curing
Electron-beam irradiation is calculable and is determined by 3
factors:
Acceleration voltage as the measure for the penetration depth
of the electrons.
Electron current
It determines the possible flow rate. The applied irradiation
dose D is connected with the electron current I and the web speed v as follows with k as
equipment factor.
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with k as equipment factor. |
The formula above shows the following details:
|
Dose and electron current are directly
proportional. |
|
If the proportion of electron current and
speed is constant, you will receive reproducible and saleable products in all production
phases including when starting up and shutting down the plant. |
|
The accelerator only takes power of the
main supply according to the web speed. |
|
Quality protection is possible when using
this formula. |
Working width
The width of the electron-bean exit window has to be adjusted to the
max. working width (object width).
Electron Crosslinking AB electron-beam
accelerators
The function of our electron-beam accelerators can be compares to a
cathode ray tube of a TV-set.
Fig. 1 Cathode ray
tube and Electron Crosslinking AB electron-beam accelerator
By means of flow of electron current a heated
tungsten cathode puts free electrons at its surface to disposal in high vacuum. These
negative charged particles (or waves) are accelerated by a negative voltage in direction
to the anode and then deflected over the screen at cathode ray tubes or the electron-beam
exit window at electron-beam accelerators. With the accelerator these electrons can pass
though a thin titanium foil from vacuum out into the air or inertgas, where they can act
on the object.
