There are more than ten kinds of test pens with different tension, which can accurately test whether the surface tension of plastic film reaches the value of test pen. Users can clearly understand whether the film is suitable for printing, laminating or vacuum aluminizing, so as to effectively control the quality and reduce the loss caused by unqualified materials.
Scope of application
Dyne pen is suitable for gravure printing, offset printing and UV printing.
Make the surface tension test pen perpendicular to the film plane and draw a line on the film surface with appropriate pressure The surface tension test pen with a smaller measuring range is easier to draw a straight line, so it does not need too much pressure; The 40, 42, 44 surface tension testing pens need to add more pressure when drawing lines. In general, six different types of surface tension testing pens are required for the first test to ensure the accuracy of measurement; If it is determined that the digital change of the film surface tension is very small, at least three different types of surface tension testing pens are required.
The surface tension test pen can easily analyze the surface energy, hydrophilicity, humidity and other small changes of different solids. The analysis method is simple and effective, and the accurate results can be quickly obtained by only marking the surface of the substrate. This is specially designed for the testing of the production line and is carried out by the factory trained operators.
During the test, an intermediate value should be selected as the starting point, such as 38mn / m. if the surface of the substrate is wet by the test pen within 2 seconds, the surface tension of the substrate is greater or just than the selected value, then a test pen with a higher value shall be selected for * * tests, and so on, until the test result is reduced to water droplets (spherical) within 2 seconds, The value of the previous test is taken as the surface energy of the substrate. It is used for comparative analysis.
If * * tests shrink into water droplets (balls), use a smaller test pen to perform * * tests until the surface is wet. This method can accurately measure the surface tension and surface wet force of the substrate, and determine whether the surface factors of the substrate meet the requirements before work, so as to adjust them to the needs of the work.
1. If the lines of the films which have been properly corona treated are evenly distributed and do not show any beads, then the surface dyne of the film is higher than or equal to the index marked on the surface tension test pen.
2. If the line of the film without proper corona treatment shrinks slowly, the surface dyne of the film is lower than the index marked on the surface tension test pen.
3. If the line of the film without corona treatment shrinks immediately and beads are formed, it indicates that the film surface dyne is very lower than the index marked by the surface tension test pen.
In industrial practice, the surface energy (surface tension) of plastics is measured by testing the ink. According to DIN ISO 8296, the ink with known surface energy is used to brush about 100 mm long ink strips on the film to be tested, and observe whether more than 90% of the ink strips shrink and form ink drops within 2 seconds. If so, replace the ink with lower surface energy and brush the ink strip, The surface energy of the test ink is corresponding to the surface energy of the film. This method can accurately measure the surface tension and surface wet force of the substrate, and determine whether the surface factors of the substrate meet the requirements before work, so as to adjust the ink, coating and viscosity to the work requirements.
Surface tension and surface wet force are very clear standards for accurately measuring the adhesion of printing ink and other materials on the surface, but there are other factors that affect the viscosity, such as static electricity and many additives. However, these factors are not often shown in the test, and even the test results are very good but actually not satisfactory. These technical issues need to be discussed with raw material suppliers. Generally speaking, the above situation will not happen to them, and the surface value of 38-41 Mn / M can meet the viscosity requirements. However, when the surface tension is below 37Mn / m, many white pages (no printing content) will be produced, and the viscosity will be poor when the surface tension is below 35MN / m.
Generally speaking, the substrate forms ink droplets, and the coating and adhesion ability is related to the surface energy. If the energy on the surface of the substrate is lower than the surface tension of the coated test solution, beads and draw lines shrink. Thus, for most printing, plastic based solvents, the test pen requires a range of 36-40 dyne / cm. Some ink based liquids require a pen between 40 and 44 dyne / cm. Some rolling and coating applications require a surface energy of 50 dyne / cm or more. Obviously, the surface energy needs to be estimated before printing, coating and rolling.
The surface tension test pen performs well on most non adhesive materials. It is important that the test fluid does not change the surface properties of the substrate. For example, if the test fluid penetrates into a fiber substrate (such as paper) causing swelling, the results may indicate that it is susceptible to moisture. Biochemical reactions between the substrate and the test solution invalidated the results.
In order to ensure the repeatability of test results, material preparation and test methods must be standardized. ASTM STD d6182 protocol specifies the test conditions and methods. According to the testing theory, it is important to standardize the surrounding environment, substrate and test method. The trainer teaches the tester to minimize all changes. The relative humidity should not exceed the standard, too high humidity will aggravate the variability of data* Finally, it is necessary to control the time of test extrusion or coating (printing). It can accurately measure whether the film surface tension reaches the test pen value. Users can clearly understand whether the film is suitable for printing, laminating, vacuum aluminizing, etc. Effectively control the quality and reduce the loss caused by unqualified materials.
matters needing attention
Be sure to cover the pen tightly after use.
When the ink is on your hands or skin, please rinse with water immediately.
Please keep away from direct sunlight and keep it in a cool place.