Aluminum plating film not only keeps many inherent characteristics of plastic film, such as strong and soft, but also obtains some functions of aluminum foil, such as light shielding, beautiful metal luster and high barrier property, etc., and the relative cost is low. Therefore, the application of aluminum plating film and its composite materials is increasing. However, in the process of using solvent-free composite to produce aluminum coating composite film, the transfer of aluminum coating often occurs, which is a headache.
1. The essence of transfer of aluminum coating
In fact, the adhesion between the aluminum coating and the substrate is less than that between the aluminum coating and the adhesive. Aluminum transfer causes the aluminum coating to migrate to the adhesive layer due to partial or large area separation from the base material, which affects the integrity of the composite film, reduces the application performance of the composite film containing the aluminum coating, and even loses the use value. Therefore, it should be paid attention to and solved in solvent-free composite.
2. Methods to eliminate the transfer of aluminum coating
(1) Aluminum plating film with bottom coating is selected
The most effective way to eliminate the transfer of aluminum coating is to select the aluminum plating film with bottom coating when purchasing the aluminum coating film, namely the so-called enhanced aluminum coating film. This film is coated with a primer to enhance the aluminum plating strength before aluminum plating, and there is a firm combination between the base glue and the film, and there is also a strong combination between the aluminum coating and the bottom glue. The aluminum coating shows that Good adhesion strength can effectively avoid the occurrence of aluminum transfer phenomenon in the aluminized composite film, but the price of the aluminum coating film is higher. When the common non reinforced aluminized film is used as the substrate, the transfer of aluminum coating should be paid more attention.
(2) Solvent free adhesives for aluminum plating shall be selected as far as possible, such as solvent-free laminating adhesive wd8117 of Shanghai Kangda new chemical materials Co., Ltd., and corresponding measures shall be taken to solve the problem according to the specific conditions of aluminum coating.
(3) Other targeted measures
① Improve the fastness of aluminum plating film.
To improve the quality of the aluminized film is the precondition to solve the transfer problem of the aluminum coating. If the quality of the aluminum coating itself is too poor, no matter what kind of composite process and adhesive can solve the problem of aluminum coating transfer. .
② Use soft adhesive.
In order to properly improve the softness of the adhesive layer, sometimes the dosage of curing agent components is appropriately reduced to reduce the crosslinking reaction degree during compounding, reduce the brittleness of the adhesive film, increase the flexibility and extensibility of the adhesive film, so as to reduce the transfer of the aluminum coating. However, the amount of curing agent used should not be too low, because the curing agent dosage is reduced, the curing degree of the adhesive decreases correspondingly The amount of curing agent must be able to ensure that the adhesive layer has enough strength after the composite film is aged.
③ The composite process was optimized.
Generally, when the soft packaging manufacturers adopt solvent-free composite process to composite PET / / vm-pet / / PE, pet and vm-pet are compounded, and then PE is compounded. However, after PET / / vm-pet is aged, the aluminum coating does not transfer. After PE is continued to be compounded, the phenomenon of aluminum coating transfer appears. The appearance of this phenomenon is directly related to various kinds of film, adhesive layer and aging time. If PE and vm-pet were compounded first, then cured, then pet, the transfer of aluminum coating would be improved obviously.
④ Improve ripening conditions. Due to the high curing temperature and fast curing rate, the film shrinks sharply and the transfer of aluminum coating is increased. Therefore, properly reducing the curing temperature and slowing down the aging rate can reduce the aluminum transfer phenomenon.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.

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