1. Corona treatment degree
The degree of treatment of the film will directly affect the quality of post-processing, must be strictly controlled. If the degree of treatment is not enough, the wettability of the film is not significantly improved, there will be poor adhesion of ink, adhesive adhesion is poor, composite film peeling force is small and other faults, on the contrary, if the degree of treatment is too much, there will be a film surface aging, adhesion decline, gloss deterioration; surface molecules are too much cross-linking, heat sealing deterioration; film is easy to adhesion (especially high temperature days in summer), the emergence of slitting and other processing difficulties, the use of Difficult to open and other problems; in short, the processing degree control principle is: under the premise of meeting the post-processing requirements, as far as possible to reduce the degree of processing, to avoid unnecessary over-processing. Commonly used critical surface tension to detect the degree of processing.
Due to the film type, post-processing form, post-processing time, etc., the degree of processing requirements are different, several film printing and composite critical surface tension value required. Immediately after processing can take a small value, and vice versa should take a large value.
2. electrode gap
Usually the electrode gap control in 1mm ~ 2mm is appropriate. Before starting the machine, the electrode gap should be carefully calibrated to make it uniform, otherwise the critical surface tension of the film will be large on one side and small on the other due to different processing strength. The knife edge of the electrode should be straight and there should be no gap, otherwise the treatment intensity at the gap will be uneven and longitudinal lines with low critical surface tension will appear on the film. After a period of time, a layer of oxide will be produced on the knife edge of the electrode, affecting the quality of treatment, which can be knocked off with an emery cloth.
3. Processing Voltage
Applied to the treatment device on the voltage increases, the treatment effect increases, but disproportionate, when the treatment voltage rises to a certain value, basically no longer change. Processing voltage is mainly based on the thickness of the product to determine, the thicker the product, the higher the processing voltage. Usually used for thin films, the treatment voltage is controlled at 10,000 to 20,000 volts.
4. Processing power
Processing power is the main factor in determining the degree of treatment, in order to achieve the critical surface tension values in Table 1, a certain amount of processing power must be applied. Due to the different processing speeds, film types, experiences, widths, etc., the applied processing power is also different. Table 2 shows the minimum power (for reference) for thermal film treatment at a processing speed of 25m/min and a film width of 0.4m. If the processing speed increases by a factor of 1, the processing power should also increase by a factor of 1; Similarly, if the film width increases by a factor of 1, the processing power should also increase by a factor of 1; cold film processing power is at least 1 times greater than the hot film. The above can also be used as a basis for purchasing the size of corona treatment machine.
5. temperature and humidity
Due to the assembly line production when the release point is in the air, so the temperature and air humidity is also a parameter that affects the corona, the temperature rises, the degree of treatment increases; humidity increases, the treatment effect becomes worse.
Commonly used printing film corona value requirements
BOPP, MOPP, KCNY ≥38 dynes
PET ≥48 dynes
BOPA ≥52 dynes
Operation steps
① According to the corona value required for the printed surface of the film, select the test solution (pen) with the same value.
② Take a clean and intact test surface, use the test pen in the lateral position on the test surface, from one end to the other, coated with a uniform and continuous test solution.
③Judgment: Observe the test liquid coated on the testing surface, whether the condition changes within two seconds of contraction, if contraction occurs, the corona value of the testing position is judged to be less than the value of the test liquid used, if no contraction occurs, the corona value of the testing position is judged to be greater than or equal to the value of the test liquid used.
Precautions
The testing position of the film should be intact, dry and free of particles and oil impurities.
② Do not use expired test pen (liquid).
③The test liquid is a multi-component volatile mixture, it should be sealed in time after use and placed in a place without direct sunlight.
Hefeng Machinery Group focuses on the development and application of surface treatment industry for more than 20 years, corona machine, corona treatment machine, plasma machine, static generator, static eliminator, dust removal machine, UV curing, UV power supply, electronic UV, UV light box, plasma treatment system, vacuum plasma, spark machine, plasma treatment, flame treatment machine, electronic spark machine, EDM impact machine, surface treatment machine, polymer Surface Flowering Machine, UV lamp, UV transformer, and so on. It is a national high-tech enterprise integrating R&D, production and sales.
Our core competitiveness comes from the fact that we never stop launching new products and designing molds, and vigorously investing in the research and development of new products, it is this guiding principle that makes us different, which also enables us to become a real solution-oriented company in the industry. From the design of the solution to the final inspection of the equipment, we pay meticulous attention to every detail to ensure that the quality of our products and customer service meets the highest standards, and with our highly qualified service team and experienced technicians, we have gained an international reputation as a solid and reliable partner.
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