In the nylon film industry, there is a joke: choose the appropriate film grade according to the weather forecast! Since the beginning of this year, there has been a continuous high temperature and hot weather in many parts of China, and the continuous heat “roasts” many relevant participants in nylon film industry. Nylon film is a polar material that is very sensitive to the external environment. In such an environment with high temperature and extremely high humility, it’s quite a nerve-wracking problem that how to make better use of nylon film, avoid product quality problems caused by some adverse factors. Here let’s come together to listen to the measures taken by Xiamen Changsu.

Seasonal climate change is related to the humidity and temperature. Specifically, in spring and summer, especially in rainy season, the relative humidity in the air is high and even saturated. In autumn and winter, the air is dry and the humidity is low; In terms of temperature, summer is much higher than winter, and the maximum difference between them is nearly 30 ~ 40 ℃ (temperature difference between South and North area).

If don’t pay high attention to these differences, it is likely to occur some quality problems during printing and lamination, for example, the adhesive is often not cured completely, impervious to dryness, and has large residual viscosity. In serious cases, it can even peel off the composite film, especially the nylon film has high moisture absorption, which is easier to produce this phenomenon.

Although nylon film is a polar material, and it also goes through the process of molecular crystallization in the production process, not all molecules in polyamide can crystallize, and there are some amorphous amide polar groups, which can coordinate with water molecules, resulting in the easy inhalation of water molecules with strong polarity on the surface of nylon film, softening the nylon film, weakening the tensile force, destabilizing the tension during production, and forming a thin water cover to block the adhesion of ink and adhesive to the film because of water absorption, thus affecting the product quality, such as wrinkling, edge warping, curling of bag mouth, inaccurate registration, misplaced bag making, composite blistering, spots, crystal dots and white spots. peculiar smell, adhesion of film surface, difficulty in coding, etc. In severe cases, it will lead to the decrease of composite peel strength, the increase of bag breaking during high-temperature cooking, and the increase of hard and brittle feel of composite film. These are the quality faults caused by the disadvantages of nylon film after moisture absorption.

First of all, once the nylon film absorbs moisture, its physical properties change, and the film becomes soft and wrinkled. For the solvent-free lamination at high speed, wrinkle caused by the moisture absorption is a hard to solve problem. Secondly, the thickness balance, film surface planeness, thermal shrinkage surface wetting tension, addition dose and so on, may affect the product quality of solvent-free lamination.

Therefore, in the climate change or wet and rainy season, special attention should be paid to the production and use of nylon film, so as to avoid the quality problems caused by various unnecessary errors in printing and laminated processes caused by excessive humidity in the air and moisture absorption of nylon film.