Dry laminator operation methods and techniques
Working principle of dry laminating machine is mainly used for the coating lamination of cellophane, aluminum foil, nylon, paper PET, OPP, BOPP, CPP, NY, PE and other roll-like substrates. The working principle of the dry laminating machine is as follows: 1. prepare first, according to the direction of the alignment of the substrate each guide roller is installed, while the adhesive is adjusted according to the proportion, start the heating system of the oven, when the corresponding set temperature is reached, and then open the drive motor, you can open the coating production. 2. coating the substrate of the release device first to go through the anilox rollers, after the adhesive coating, and then through the drying channel for dry bath, that is, to complete the coating process. 3. Composite by EPC air-liquid correction into
Dry laminators are mainly used for coating lamination of cellophane, aluminum foil, nylon, paper PET, OPP, BOPP, CPP, NY, PE and other roll-like substrates.
The working principle of the dry laminator is as follows:
First, according to the direction of the alignment of the substrate each guide roller installed, while the adhesive will be proportionally adjusted, start the heating system of the oven, when the corresponding set temperature is reached, and then open the drive motor, you can open the coating production.
The substrate of the unwinding device should first pass through the anilox rollers, be coated with glue, and then pass through the drying channel for dry bath, that is, to complete the coating process.
The laminating process is achieved by entering the laminating section through EPC air-hydraulic correction and laminating with the substrate in the second unwinding section.
4. Cooling winding
After cooling the rolls, the overall production processing of the substrate is completed, and the following issues should be noted during production.
(1) Adjust the flatness of the substrate by adjusting the position of the deflection roller.
(2) Adjust the compounding pressure between the two compounding rollers by adjusting the relative distance between them.
(3) Control the traction tension and winding tension of the substrate by adjusting the tension clamps of the clutch and brake to make the machine run smoothly, so as to get good coating quality and laminating effect.
Dry laminated products often have defects such as bubbles and wrinkles and poor adhesion.
1、Way to avoid air bubbles in the finished product
(1) improve the depth of the adhesive or choose a good wetting adhesive.
Too thin or poor wettability of the adhesive is easy to flow, so that the substrate is unevenly glued, thus prone to longitudinal or horizontal flow lines. The part of the small amount of glue is likely to appear bubbles, you can improve the concentration of adhesive or choose a good wetting adhesive to reduce the bubble generation.
(2) Corona treatment of substrate
Some plastic film substrate surface adhesion adhesive ability is poor, in order to improve the adhesion ability of the surface of such substrates, to ensure the quality of coating, require the surface tension of the substrate to reach 42 ~ 56Mn/cm, you can add a set of corona processor before the coating of the substrate surface corona treatment, so that the surface hair to enhance the role of surface tension, so as to improve the amount of adhesive on the surface of the substrate to Avoid bubble generation.
(3) Correct installation and adjustment of the squeegee in the coating, the size of the amount of glue mainly depends on the depth of the anilox roller cavity, the deeper the cavity the more glue, the shallower the cavity the less the amount of coating, the correct adjustment of the squeegee can ensure a more uniform amount of glue, thereby reducing or avoiding the appearance of bubbles.
In the actual operation process, to use the pressure hammer method to adjust the whole scraper pressure is appropriate, scraper pressure is generally in 200 ~ 400kpa, coating, if the scraper role in the anilox roller pressure is too small, when there are impurities mixed in, it is easy to scraper top up the formation of gaps, so that the coating is not uniform.
As the surface of the anilox roller is not smooth, if the scraper is installed at too large an angle, in its high-speed operation, the elastic scraper blade is prone to vibration or jumping, so that the rubber pops up, causing an increase in the amount of coating difference, the general scraper and the net roller contact radial angle selection between 15 ~ 30 °.
Scraper flat, the amount of coating is uniform, otherwise, the difference in the amount of coating becomes large, the flatness of the scraper depends on the installation method of the scraper, the other place may also be related to the knife frame groove inside or blade, lining piece sticky impurities, therefore, in the installation of the scraper should first wipe clean lining piece, and then put the new blade behind the lining piece, installed in the knife frame groove, screwing knife back screw, should first start from the middle of the blade gradually tighten to both sides, and Both sides to take turns to tighten, in order to prevent the blade warp, tightening the screw is generally completed by two or three times, while tightening the screw, while using the cloth to clamp the blade and liner, and force to the outer side of the tension, so that the finished assembly of the scraper is relatively flat.
(4) The appropriate drying temperature
Drying temperature is appropriate, can make the substrate surface adhesive fully dry bath, general dry bath temperature adjustment to 80 ~ 100 ℃ is appropriate, a number of bath temperature is too high, the adhesive surface has been crust, the surface of the following part is not dry, so that the exhaust gas is difficult to escape, it is easy to appear blistering. On the contrary, the dry bath temperature is too low, the adhesive can not be completely dry, after a period of composite finished products, due to the natural volatility of the adhesive, will also form bubbles, composite composite heating rollers to improve the temperature, reduce the composite angle, conducive to bubble discharge composite film.
(5) adjust the compound pressure and speed
Compound pressure is not enough, easy to produce bubbles, improve the composite film pressing temperature and compound pressure, it can greatly reduce the bubbles. Since the contact of two composite rollers is line pull contact, so reduce the operating speed of the equipment can increase the pressure paste time between the composite rollers, so that the bubble is fully discharged from the composite film, also conducive to reducing bubbles.
In addition, in order to prevent dust adhesion on the composite surface of the film, it is necessary to clean the anilox rollers and film, clean the composite rollers, and pay attention to environmental hygiene.
2．Ways to avoid wrinkling of finished products
(1) Reduce the tension of the traction substrate
Film stretching is too large, not enough walking shape, and it is easy to cause wrinkling of composite film when cooling and shrinking. Properly reducing the running tension of the substrate can reduce wrinkling.
(2) Adjust the flatness of the substrate
If there is parallelism error of each guide roller assembled on the dry laminating machine, some plastic film substrates are easy to produce wrinkles on the guide roller, and the flatness of the substrate can be adjusted by adjusting the position of the deflection roller during production. Of course, we can also add some spreading rollers or bending rollers to stretch the film in the appropriate part before lamination.
(3) Adjust the pressure of laminating rollers
In the production process, special attention should be paid to adjust the compounding pressure of the two compound rollers. Uneven compounding pressure, such as low pressure, is most likely to trigger wrinkling of the compound film.
In addition, cleaning the composite rollers and replacing the bad rubber pressure rollers can also avoid wrinkling of the composite finished products. When designing, if a preheating roller is added before the composite to preheat the surface of the second release substrate, so that the temperature of the second release substrate and the coated substrate before the composite remains basically the same, it can also prevent the curl deformation of the composite film after cooling.
3、Ways to avoid poor adhesion of finished products
(1) The amount of adhesive coating is too little or part of the substrate surface is not coated with adhesive, which will lead to the difficulty of laminating the two substrates together. We can choose anilox rollers with deeper mesh cavities, or increase the amount of adhesive coating on the substrate surface by increasing the pressure of rubber rollers and reducing the contact pressure between squeegee and anilox rollers. For some plastic film substrates, corona treatment can be carried out before coating to make the surface hairy, so as to improve the ability of the substrate to adsorb adhesive and increase the amount of glue applied to its surface.
(2) Choose the right drying temperature
Temperature is too high or too low, will affect the composite film adhesion fastness. Coated substrate dry bath when the heat temperature is too high or after high temperature cooking, will make the surface layer of the adhesive is carbonized, thus destroying the adhesive junction ability. Drying temperature is too low, the adhesive curing is not complete, the adhesive viscosity is poor, compound is not firm and after a period of time, the composite film is easy to form bubbles, destroy the composite quality of the product, of course, we can choose high temperature and good resistance to cooking adhesive to adapt to the higher temperature drying, for example, with polyurethane adhesive.
(3) Appropriate increase compounding pressure
Compound pressure is too large or uneven pressure at both ends of the compound rollers will cause the surface of the composite film wrinkles, the formation of empty tunnels at the wrinkles after the compound, affecting the finished product adhesion fastness. Appropriate increase in compound pressure is conducive to improving the bonding force of the compound.
In addition, in order to improve the bonding effect and quality of composite, to try to avoid foreign objects, dust and other debris adhering to the adhesive or substrate composite surface.
*** Translated with www.DeepL.com/Translator (free version) ***
When operating, we should carefully observe the various problems and faults that occur during the production process, and reasonably use the above methods to troubleshoot them. When there are multiple problems or faults, a single method may not be able to take into account, at this time should avoid the light and focus on solving the key problems and then choose other methods to solve the secondary problems one by one.