Waterborne adhesives will make a difference (below)

Development: More forms of aqueous adhesives will be available

Although the one-component waterborne adhesive has good pro-aluminum properties, it is not easy to produce the phenomenon of aluminum transfer, and its strength on the aluminized film is also higher than the solvent-based adhesive. Moreover, in the compounding of plastics such as OPP, CPP, and PE, the composite strength of water-based adhesives can exceed 1.0 N/15 mm, and the strength is higher in PET-based composites. However, Shishi Xinguang Packaging Co., Ltd. of the dry laminating machine that had no connection corona treatment began formal use of water-based adhesive two years ago. The main purpose was to reduce the transfer of the aluminized film and shorten the lead time. Through long-term use, the company's technical staff has summed up some experience for your reference: compared with solvent-based adhesives, although the operation of water-based adhesives is relatively simple, but also pay attention to control some aspects.

(1) Since the amount of water-based adhesive sizing is very small, the engraved roller must select a dense and shallow laser engraved roller, usually 200 lines/35U, and the opening of the laser roller mesh is relatively large, so as to ensure the water-based adhesive The adhesive can be better transferred to the film.

(2) Before using the water-based adhesive, the water-based adhesive must be slowly stirred in the barrel for 5 to 10 minutes to ensure that the various additives in the water-based adhesive are uniformly mixed.
(3) The surface tension of the film should be tested before gluing. It is better to use dyne solution instead of dyne pen. The surface tension of the film should be at least 3.8 × 10-2N/m, and the surface of the ink should be Testing.
(4) Use a counter-rotating roller as much as possible. The reverse flattening roller has a great influence on the appearance. By adjusting the speed, the appearance can achieve the best effect.
(5) The oven temperature is set to 80 °C, 85 °C or 95 °C (the temperature can not be switched on until the set temperature). Because the air volume is important for the drying of aqueous adhesives, the air inlet and exhaust of the oven must be maximized. The compound hot drum temperature is set to 75-85°C, and the compound hot drum pressure is set to maximum.
(Note: For the setting of temperature, it is recommended to operate as much as possible under the above conditions when considering the tolerance of the film and process.)
(6) An air diaphragm pump must be used between the glue tank and the water-based adhesive barrel. Clean the pump before use. Do not mix with the solvent.
(7) To prevent jamming, the scraper must be released during shutdown and the top roller soaked in the aqueous adhesive to maintain rotation.
(8) In order to prevent air bubbles from being generated when the speed is too high, you can put a uniform ink stick in the tank.
(9) After use, wipe off the aqueous adhesive on the top roller with water and then thoroughly clean with ethyl ester. If blockage occurs, it needs to be cleaned with butanone.
(10) The storage temperature of the water-based adhesive must not be lower than 5°C, nor can it be exposed to the sun, and it cannot be contaminated by dirt and solvents.
(11) Apparently, if there are scratches, there are generally two reasons: First, the scraper is not clean and the scraping phenomenon is caused. At this time, the scraper must be cleaned; second, it is blocked, and the roller must be cleaned in time.

Because the water-based adhesives bond the two films together by the film forming principle, its compounding effect is very stable, and the produced products can be cut immediately. If the quality of the composite is not good due to the process or substrate, it can be seen in the first time after the machine is down, and the problem will not be discovered after mass production.

In the two years of use, Shishi Xinguang Packaging Company concluded that the use of water-based adhesives in the aluminizing process is indeed a great advantage over traditional solvent-based adhesives. Recently, the company has begun to try two-component water-based adhesives. Adhesives are used in more packaging structures.

Source: Print World