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Ink, Dynes, Pens
Adhesion
Adhesion of a liquid to a solid surface is given by the Young-Dupre equation.
W A = g (1 + cos u)
g = surface tension
u = contact angle of liquid on surface
• Contact angle is a function of surface energy levels of the liquid and the solid.
• High level of energy in the liquid produces a large contact angle
Surface Tension
Surface tension is the property of a liquid arising from unbalanced molecular forces at or near the surface. If it is higher than the surface energy of a material, the liquid tends to form droplets rather than spread out. Another name for an ink‘s surface tension properties is „wettability“.
Dyne Levels
Surface tension is normally measured in energy units called dynes (mN). A dyne is the amount of force required to produce an acceleration of 1cm/sec on a mass of 1g. The dyne level of a material is called its surface energy.
If the liquid has a dyne level lower than the material‘s surface energy, then the liquid will spread out over its entire surface in a uniform wet layer. If the ink‘s dyne level is equal to or higher than a material‘s dyne level, the liquid will become cohesive and tend to remain in droplets.
• Thus water will prefer to cling to itself, rather than to low energy surfaces, whilst solvents will readily spread and be attracted to a plastic surface film having a surface tension > 30 dynes/cm
• For good adhesion in printing, the surface energy of the polymer should be at last 10 dynes higher than the surface tension of the ink
Prefilled Pens
• NON TOXIC ~ Contains NO Formamide
38dyne part number: 261.0013
40dyne part number: 261.0074
42dyne part number: 261.0075
44dyne part number: 261.0085
Jumbo Pens
• NON TOXIC ~ Contains NO Formamide
36dyne part number: 261.3036
38dyne part number: 261.3038
40dyne part number: 261.3040
42dyne part number: 261.3042
44dyne part number: 261.3044
46dyne part number: 261.3046
48dyne part number: 261.3048
50dyne part number: 261.3050
Inks
• NON TOXIC ~ Contains NO Formamide
36dyne part number: 261.4036
38dyne part number: 261.4038
40dyne part number: 261.4040
42dyne part number: 261.4042
44dyne part number: 261.4044
46dyne part number: 261.4046
48dyne part number: 261.4048
Empty Pens
part number: 261.1001
Important
The test inks should not be used or
stored at temperatures above 20°C or below freezing, to prevent inaccurate
dyne level readings.
The bottled inks should not be exposed
to direct light. Therefore keep them in their original box with the lid closed
when not in use. Also, repeated exposure to air of the bottled inks, will alter the dyne levels.
Properly sealed bottles prevent this occurring.
We recommend the replacement of the inks regularly if the bottled inks are
frequently opened at atmosphere.
Recommendations
If bottled inks are exposed to the air on
a daily basis:
› dispose of remaining ink after 3 months.
If bottled inks are exposed to the air on
a weekly basis:
› dispose of remaining ink after 6 months.
If bottled inks are exposed to the air on
a monthy basis:
› dispose of remaining inks after 12 months.
Test Pens are designed to indicate film surface treatment levels on polymer based substrates and establish that the material is correctly treated prior to printing. The barrel of the pen is printed with the minimum dyne level that the
ink will determine.
Application
Draw a line across the material being
tested. Apply sufficient vertical pressure to enable a good ink flow. Excessive pressure will adversely affect film surface treatment levels.
Dyne Level Measurement
1. Properly Treated:
The ink lies evenly on the material in
a continous line. There is no ink reticulation. The surface tension of the material is at, or higher than, the dyne level of the ink.
2. Not Treated:
The ink reticulates into droplets. The
surface tension of the material is well below the dyne level of the ink.
3. Partial Treatment:
The ink line is defined but there is partial reticulation from the edges. The surface tension of the material is just below the dyne level of the ink.
Pillar Technologies, Blauenstr. 67-69, 79576 Weil am Rhein, Germany
Tel.: +49 7621 7905 510
Fax: +49 7621 7905 511