Aluminized Laminated Film

Food packaging and pharmaceutical packaging:

BOPP / VMCPP aluminized laminated film is widely used in food packaging and pharmaceutical packaging, especially in biscuit packaging, snack foods, and pharmaceutical granule packaging.
However, the peeling strength of this aluminized composite film structure is prone to be low. The deviation in peeling strength of the BOPP / VMCPP structure is mainly manifested in ink transfer, aluminized layer transfer, and adhesive delamination. When these phenomena occur, the peel strength will be very low, and the test data is even as low as 0.2N / 15mm, while the national standard clearly stipulates that it must be above 1.0 N / 15mm .

Therefore, there is a lot of trouble for flexible packaging industry, and some experienced practitioners will determine whether to pass them through the rubbing test Aiming at the three phenomena of poor peel strength of BOPP / VMCPP aluminized laminated film, through repeated experiments, the main reasons and improvement plans are analyzed on the original and auxiliary materials, as follows:

A. Large area ink transfer

With the continuous improvement of the country’s requirements for environmental protection, benzene-soluble chlorinated polypropylene inks have been gradually eliminated by the market, and replaced by polyurethane integrated inks. However, the adhesion of polyurethane integrated ink on BOPP material is relatively poor, and the fastness of the tape is relatively poor when printing is finished, the use of 3M standard adhesive tape peeling will appear large area off. After laminating and curing, the peel detection will easily cause large-area ink transfer.

In view of the poor adhesion of polyurethane integrated ink on BOPP film, we can take a series of methods to improve it. For example, add curing agent into the ink

(add a small amount of curing agent for more times), the ink layer forms a cross-linking reaction to form a large molecular chain, thereby forming a protective film to ensure that the adhesive does not erode the ink layer in a large area during compounding to reach the BOPP interface, and finally peel off the ink from the BOPP film.

In addition, BOPP adhesion promoter can be added to the ink and the surface tension of the coro

na surface of BOPP can be improved. BOPP surface tension should be controlled above 42dyn as much as possible. At present, BOPP printed film produced by Gettel Group China and BOPP printed film produced by Jiangsu Shuangliang can basically meet this requirement, and after many process verifications, the effect of BOPP with a thickness of less than 18um is relatively better.

B. Large area transfer of aluminum plating

The aluminized adhesion of aluminized CPP has a great influence on the laminate strength, and the adhesion of aluminized layer mainly depends on the CPP substrate and the aluminizing process. CPP substrate using modified CPP can greatly improve the adhesion of the aluminized layer. Plasma treatment during aluminum plating can also improve the strength of aluminum plating on CPP substrates by removing small molecules from the surface of CPP. In addition, the selection of a suitable adhesive and low-temperature curing time can reduce the damage to the aluminum coating. It is recommended to use glue with large molecular weight, good flexibility and low stress during curing.

C. Adhesive delamination

When laminating, the adhesive usually uses a two-component glue. If the molecular chain formed after glue cured is easy to break, it will cause the adhesive to break itself and eventually reduce the peel strength. Irrational formulation of the composite process will also greatly affect the peel strength, such as use VMCPP for gluing, too strong tension , with foreign matter on the running roller, too high temperature and too long-term curing.

Conclusion:

In the dynamic landscape of flexible packaging, addressing peel strength challenges in aluminized laminated films is crucial. By understanding and implementing the discussed solutions, manufacturers can enhance the quality of their packaging materials, meeting and exceeding industry standards.