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| Corona Discharge
Treater |
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| Introduction |
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In
the packaging industry , plastic films or webs
are finding more and more applications. The
plastic film today includes many different materials
and new permutations and combinations of materials
are added. The only problem encountered by the
industry is that of plastic adhesion. A major
component of these problems is due to the fact
that many plastics have chemically nonporous
surfaces with low surface tension i.e. most
plastics are hydrophobic and are not wettable.
These properties result in secondary assembly
and decorating concern - bonding, printing,
coating and painting.
Surface pre-treatment on today's high performance
engineering resins solve many adhesion problems
while increasing bond strength performance.
As a general rule, acceptable bonding adhesion
is achieved when the surface energy of a substrate
is approximately 10 dynes/cm greater than
the surface tension of the liquid. In this
situation the liquid is said to wet out or
adhere to the surface. Surface Tension which
is the measurement of surface energy is the
property, due to molecular forces, by which
all liquids through contraction of the surface
tend to bring the contained volume onto a
shape having the least surface area. The higher
the surface energy of the solid substrate
relative to the surface tension of a liquid,
the better its wettability.
Corona Treatment
Corona Treatment is a process of high speed oxidation which create polar molecules on the film surface. The energy of the corona will break the bonds of the atomic structure of the substrate. The oxygen rich ozone developed by the corona discharge will readily fill the open valancies which create a charge surface thus improving the surface characteristics and wettability. The Treated surface tends to go back to it's original dyne level after a certain period of time. This Decay of Treatment is exponential in nature and vary for different type of materials, it's additive content and other factors. Proper packaging reduces the rate of decay. Generally the effect of treatment remains for about a month.
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| Film
Treater |
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Our model ranges from
the smallest unit of 1 Kwatt to the
largest unit of 16 Kwatt. The equipment
is for width ranging from 100 mm to
3500 mm and web speeds upto 120 mts/min.
Features :
- Internationally Approved IGBT Technology.
- Ultra High Frequency.
- Soft Start.
- Zero Speed Cut Off System.
- Power Synchronization with Line Speed.
- Fault Indicators.
- Clear Silicon Tube for longer life.
- Bare Roller System.
- Maximum Operator safety.
- Audio/Visual Alarm.
Electrode System
- Split Box Treatment
Assembly.
- Key Type Electrode for Adjustable
& Skip Treatment.
- Treatment Rolls with Silicon Sleeves.
- Alluminium Construction for light
weight and low corrosion
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| Applications |
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Application:
Corona Treatment is used for Blown Films,
Cast Films, Sheet Extrusion Metallic Substrates,
Polyester, Lamination, Aseptic Packaging
Materials, Printing and UV Applications.
PRINTING:
The pre-treatment of surface of plastic
films by means of Corona Discharge has
become the most applied process due
to its high efficiency, ease of control
and simple handling to improve adhesion
of inks to various plastics films like
HDPE, LDPE, PP, BOPP, Polystyrene, Polyester
etc.
LAMINATION:
Normally pre-treated films are used
for lamination. Corona Treaters are
installed on Extrusion or Adhesive Lamination
Plant to increase the bonding strength
between the webs and also to compensate
for the drop in the level of treatment
due to storage of films. Thus optimum
quality of lamination is achieved.
COATING:
Pre-treatment by Corona Discharge of
the substrate will ensure that a better
bond will result from a subsequent coating
operation. After Treating the adhesion
between the substrate and the film coating
is significantly improved and in many
cases a chemical primer can be dispensed
with it. Dispersion Coating can also
be improved with pre-treatment by Corona
Discharge. In the case of dispersion
coating of polyester film for photographic
purposes, it is essential that the pre-treatment
takes place immediately before coating
eliminating the need for an adhesive
layer.
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| 3D
Treater |
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Our
Wide Range of 3D Corona Treaters have
the latest IGBT Technology with PWM Control
to give uniform treatment at low Power.
With Corona Treatment there is a 100 %
reproducibility of treatment , unlike
flame treatment where the parameters cannot
be set electronically but have to be left
to the skill of the operators.
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CORONA
AGAINST FLAME TREATMENT
1.ADVANTAGES OF
USING 3D TREATERS
- No Uneven or Inconsistent Treatment.
- No Danger of Fire.
- No Shrinkage.
- No Burnmarks or Loss of Gloss.
- No Rejects.
2. Applications:
The 3D TREATER can be used to treat
different plastic material like PP,
LDPE, HDPE, etc. for application such
as Pad Printing Screen Printing,Offset
Printing , Labeling etc.
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| Dyne
Level Testing |
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Select the required dyne pen. Place the
product to be tested on a flat surface.
Firmly press the marker pen applicator
tip down onto the product until solution
is drawn into the tip. |
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Using a light touch, draw the pen across
the length of the pretreated surface one
time to apply a thin fluid layer. 2-3
parallel passes are recommended. |
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Note the time it takes for the liquid
to break into droplets. The reading of
the liquid behavior should be observed
in the center of the liquid. |
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If the liquid does not break into droplets
after a few seconds, then the surface
energy is assumed to be a minimum of the
dyne level indicated by the marker. |
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If the liquid breaks into droplets in
less than two seconds, repeat the test
using the next lower dyne marker pen.
Adjustments to the pretreatment process
may be necessary. |
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Never retest the same location on a sample.
Do not touch or contaminate the surface
to be tested. Dyne solutions are also
available in bottle containers, and may
be used in conjunction with a Cotton Swab
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The degree or quality of treatment is
affected by the cleanliness of the plastic
surface. The surface must be clean to
achieve optimal pretreatment. Surface
contamination such as silicone mold release,
dirt, dust, grease, oils, and fingerprints
inhibit treatment. Material purity is
also an important factor. The shelf life
of treated plastics depends on the type
of resin, formulation, and the ambient
environment of the storage area. Shelf
life of treated products is limited by
the presence of low molecular weight components
such as antioxidants, plasticizers, slip
and antistatic agents, colorants and pigments,
stabilizers, etc.
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| Woven
Sack Treater |
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Corona Treatment
On Woven Fabric
Corona Treatment on laminated or unlaminated(HDPE/PP)increase
Surface bonding strength by creating
Polar molecule on the surface.As a result
excellent bonding of inks takes place.On
untreated fabric, inks adhere on the
surface by means of mechanical friction
& are easily released by rubbing
or adhesive Tape test.
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Corona
Treatment On Woven Fabric
Corona Treatment is a process of high
speed oxidation on the polymer surface.This
makes the surface polar in nature.This
process is limited to surface molecules
& doesn't affect the strength of
material.
Application
Woven Sack Treater is used to treat
seperate HDPE/PP Woven Sacks or Rolls
prior to printing.
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