Plstic Film corona treatment tips
For most film printers, the biggest problem in surface treatment work is that they do not understand the film. Being able to control surface treatments is a key factor in balancing the differences between printers and equipment suppliers and equipment suppliers.
In general, today's packers purchase from multiple film suppliers, and this multi-channel purchase method inevitably leads packaging companies to use different pretreatment methods of film.
In fact, it is the same manufacturer that sometimes causes different film properties due to the difference in the degree of aging after film processing.
Special remind printers to pay attention to the "add-on" effect of thin film organisms. Chemical activation or anticoagulants can affect the depth of treatment on the surface of the film. These special issues will gather on the surface of the film and act as a barrier.
In addition, the pigments and additives in the film can also affect the treatment of the film, reducing its efficacy, and can also cause particles or dust to precipitate, affecting the use of processing equipment. Although this situation should usually be attributed to cleaning issues rather than product issues, this phenomenon does lead to an increase in the number of shutdowns.
It is important to decide the type and source of the film. After all, surface machining is not an optional matter. In order to achieve proper tackiness and humidity, water-based ink systems usually require the surface tension of the substrate to reach 43 film. Both nylon polyester and PET polyester must be surface treated to meet the requirements of water-based inks.
Thinner films are used more and more widely because they are thinner and more economical. The key to handling this film is to have a drive shaft roller, and if necessary, an idler wheel. If the web tension is very low and the printing speed is particularly fast, it may be helpful to add a fixed or driven micro-wheel to the roller of the processor.
Solo System recently developed a processing time for the thinnest film under high speed printing presses.
Checking the Compatibility of Ink and Printed Materials Water-based inks are environmentally friendly and are becoming an indispensable printing ink in the packaging industry, especially in narrow-web printing, but it also requires that processing equipment be changed accordingly. Because the water-based ink has a higher tension relative to the printing material needed for the solvent ink (the former is about 42 dyne and the latter is 38 dyne), the output power of the corona machine will also change, which requires that the processing equipment must also be able to Working under high power.
The simple design is to make the equipment occupy as little space as possible, and the processing equipment should also have high flexibility in order to be more suitable for packaging plants. A thinner film should actually be easier to handle than a thick film because it does not require too high a watt density. In order to reduce the problem of plugging (pinhole problems), the processing equipment must be suitable for various operating media.
It is the result of the collaborative work of each part that each department should not deal with its own surface quality. Therefore, the film printing manufacturer should negotiate with the film supplier when purchasing any corona processing equipment. For any packager, the best way to do this is to call together all the people including film, ink and processing equipment suppliers to discuss this issue. At the same time, it proposes a corresponding solution to the worst possible situation.
Some people think that the corona treatment with excessive strength can increase the adhesion and drying of the film. In fact, this is completely wrong. (Over-treatment) can impair the sealing properties of the film and can even cause the film to distort. Moreover, the new stretch film and multi-layer film have an intelligent and extensible structure, which is specially used for the sealing treatment of high-speed packaging equipment, and these properties are changed due to improper corona treatment.
Do not have warpage. The biggest problem with thin films (especially those that are ultra-thin films) is the tendency to warp after corona treatment. The warped film had to be back-treated. But the backside processing will cause three problems:
1) Harden the problematic part, which will make it impossible for the film to fully expand;
2) When the final packaging, it is impossible to achieve a good sealing effect;
3) Severely affect the processing depth of the treated film.
In order to avoid the occurrence of this phenomenon, increase the rewinding device on the processor, or increase the tension of the film, or add another Corona treater Rolls. The distance between the electrode and the Corona treater Rolls is very important. If the distance between the electrode and the Corona treater Rolls is unevenly distributed, the final result is that the entire roll of film is also treated unevenly.
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