Barrier Technology Of High Barrier Materials

In order to improve the barrier performance of barrier materials, the following technical methods are commonly used:
1. Multi-layer composite
Multilayer composite refers to the process of combining two or more films with different barrier properties together through a certain technique. In this way, in order for the penetrating molecules to reach the interior of the packaging, they have to pass through several layers of film, which is equivalent to extending the permeation path and improving the barrier performance.
This method combines the advantages of various membranes to prepare a composite thin film with excellent comprehensive performance, and its process is simple.
However, compared with intrinsic high barrier materials, using this method to prepare thin films is thicker, prone to problems such as bubbles or cracking wrinkles that affect barrier performance, and has relatively complex equipment requirements and higher costs.
2. Surface coating
Surface coating refers to the use of physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), molecular layer deposition (MLD), layer by layer self-assembly (LBL), or magnetron sputtering deposition techniques to deposit metal oxides or nitrides on polymer surfaces, thereby forming a dense and barrier resistant coating on the surface of thin films.
However, these methods have problems such as time-consuming processes, expensive equipment, and complex processes, and may also produce defects such as pinholes and cracks during service.
3. Nanocomposite materials
Nanocomposite is a kind of nanocomposite prepared by interpenetrating composite, in-situ polymerization or sol gel method using impermeable and large aspect ratio flake nanoparticles. The addition of sheet-like nanoparticles can not only reduce the volume fraction of polymer matrix in the system to decrease the solubility of permeable molecules, but also prolong the permeation path of permeable molecules, reduce the diffusion rate of permeable molecules, and improve the barrier performance.
4. Surface modification
Due to frequent contact with the external environment, polymer surfaces are prone to affect their surface adsorption, barrier properties, and printing.
In order to better apply polymers in daily life, the surface of polymers is usually treated. Mainly including surface chemical treatment, surface grafting modification, and plasma surface treatment.
This type of method requires easy to meet technical requirements, simple equipment, and low one-time investment costs, but cannot achieve long-term stability. Once the surface is damaged, the barrier performance will be seriously affected.
5. Bidirectional stretching
By biaxially stretching, polymer films can be oriented in both longitudinal and transverse directions, improving the orderliness of molecular chain arrangement and packing more tightly, making it more difficult for small molecules to pass through, thereby improving barrier properties. This method complicates the preparation process of intrinsic high barrier polymer films and makes it difficult to significantly improve barrier properties.