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Photo Emulsion H2040
is used in textile printing for engraving perforated
Nickel Rotary Screens & Hardened Photo Emulsion
H2040 can be decoated with Stripper AG 3030
Colour : Blue, after curing
Green. White also Available on request.
| Advantages
: |
| * |
High
resolution emulsion for universal use. |
| * |
Easily
processed standard emulsion with excellent resistance
to all textile printing pastes. |
| * |
Very
fine details, hardly affected by overexposure. |
| * |
Good
durability of printing and excellent accuracy
of stencil making. |
| * |
Suitable
for squeegee or magnetic rotary screen printing
machine. |
Sensitizer
: With 5 % Sensitizer.
Resistance
: After polymerization ( 2 hours at 1800
C ) the emulsion is resistance to all printing pastes.
| Directions
for use : |
| 1) |
Washing the
Screen : Immerse the Nickel Screen into Degreaser
AG for around 10 minutes, take out and rinse with
water, dry at low temperature in an oven. At the
same time, prevent the screen from being stained
with dirt ( it is necessary to wear protective
gloves avoiding corrosiveness ) |
| 2) |
Preparing the
Photosensitive Emulsion: It should be operated
under a gentle yellow light ( prohibit from operating
in no opacifying condition ). 50 ml of photosensitizer
solution is added into 1000gm of Engraving emulsion
H2040, stand for 1 - 2 hours to let off bubbles
in a cool and dark place. Then maintain the prepared
Photo emulsion at 5 - 15 0C a constant temperature
storage box ( a seal cover is needed to avoid
skinning ) |
|
3) |
Coating: |
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*
HAND COATING |
| a) |
Round reinforcing
rings should be inserted at each end of the screen.
The emulsion should be applied at an even speed,
using a circular rubber squeegee, starting at
the base and working up to the top of the screen. |
| b) |
Depending on the
screen mesh count, two or three additional coats
should follow with intermediate drying in between
coats at a temperature of 20 - 30 0C. A drying
cabinet with good air circulation is recommended
for this process. |
| c) |
Particular attention
should be paid to the circular rubber squeegee
with regard to the thickness and quality of the
applied coating. The basic requirements for a
good squeegee are : optimum circumference, material
thickness, firmness of the rubber, freedom from
cracks and dirt. |
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*
MACHINE COATING |
| |
An emulsion layer
is applied to a rotary screen in a single coating
action, the thickness of which equates to sever
hand coating layers. The viscosity of the photo
- emulsion may be adjusted to suit machine application
by diluting a standard emulsion with approx. 20
% distilled water.
300gm of the prepared emulsion is added into a
clean scraper ring and coated on the clean screen
with a speed of 10-20 cm / min., then dried at
35-40 0C and 60 % relative humidity in an oven
circle wind and not more than + - 2 0C temperature
differences. |
| 4) |
Exposure: |
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Fix the coated
screen on a exposure machine and fit the manuscript
closely. Recommended exposure time : Since
local working conditions can vary considerably
(such as light source, temperature, air humidity)
we recommend determining your own ideal exposure
time.
Reference time : 5 - 8 times on a scanning machine
or 1 - 3 minutes on a stationary exposure machine. |
| 5) |
Development: |
| |
The exposed screen
should develop timely by putting it in water at
5 - 30 0C for approx.3 - 5 minutes, then washed
until patterns appear clearly, then rinse off
the leaked emulsion with water under low pressure,
and dry at 50 - 60 0C in a constant temperature
oven. |
| 6) |
Retouching: |
| |
Inspect the dried
screen on an examination shelf. It is necessary
to re-touch the stencil with retouching liquor
for rotary screen if there are pin holes, pattern
leakage or screens stoppers. |
| 7) |
Curing: |
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Curing the retouched
screen at 180 0C for 30 minutes in a constant
temperature oven until the film becomes yellow
- green. Only this temperature ensures complete
resistance to almost all known printing pastes
etc. Then take out to bind with end-ring after
cooling down.
It must be considered that many curing ovens have
wide temperature variations between the top and
bottom. So it is absolutely essential to make
sure that the required minimum temperature is
achieved in the coolest part of the oven. To eliminate
these temperature variations, the screen should
be turned upside down after approx. 30 minutes.
We have found that the main cause of temperature
variations is insufficient air flow and hence
the heat loss. Evidence of this situation can
be observed on the screen, as the emulsion does
not have uniform colour over the length of the
screen. When a screen is under-cured due to low
temperatures, the emulsion will not have optimum
chemical resistance and when screen is over-cured
due to excessive temperatures, damage to the nickel
may result. |
Packing
:
10kg in a special plastic barrel which is packed in
20 kg carton box.
Storage
:
* Not sensitized : 12 months from date of manufacture,
when stored dark cool.
* Sensitized : 3 days, when stored dark cool.
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