Multilayer coextruded films have become indispensable in modern packaging due to their remarkable barrier qualities. These films, made up of numerous layers with different functionalities, are designed to provide a balance of strength, flexibility, and, most significantly, barrier performance. This article delves into the deep details of how multilayer coextruded films improve barrier qualities in packaging applications.

Understanding Multi-Layer Coextruded Films

Multilayer coextruded films are a sophisticated blend of many polymers, each of which contributes unique qualities to the overall structure. To generate a film with a specific material arrangement, the layers are independently extruded before being merged in a single extrusion process. The key to their effectiveness is the judicious positioning of these layers, each designed to serve a specific purpose in improving barrier qualities.

Improved Barrier to Oxygen Permeation

Oxygen is a major contributor to the deterioration of packaged items, especially in the food and pharmaceutical industries. Multilayer coextruded films address this issue by including oxygen barrier layers. These layers are often composed of materials such as ethylene vinyl alcohol (EVOH) or polyamide (PA), which are known for their superior oxygen barrier characteristics.

EVOH, in particular, is quite effective due to its poor oxygen permeability. When this layer is placed between other polymer layers, it creates a strong barrier against oxygen ingress. This means that even highly oxygen-sensitive items can keep their freshness and quality for an extended period.

Moisture Barrier Enhancement

Moisture has a substantial impact on product quality and shelf life. Multilayer coextruded films use moisture barrier layers to prevent moisture penetration. Polyethylene terephthalate (PET) and polyethylene (PE) are often utilised for these applications.

PET, which is known for its superior moisture barrier qualities, is frequently utilised as a barrier layer in these films. By carefully managing the thickness and positioning of the PET layer within the film structure, producers may successfully prevent moisture from accessing the package. This is critical for products that are susceptible to moisture-related degradation, such as electronics and some medications.

Protection against Light and UV Rays

Light and ultraviolet (UV) radiation can cause degradation and discoloration in a variety of items. Multilayer coextruded films guard against these dangerous factors by including UV barrier layers. Materials such as titanium dioxide (TiO2) and hindered amine light stabilisers (HALS) are frequently employed for this purpose.

The UV barrier layer functions as a shield, blocking UV radiation from reaching the packaged product. This is especially critical for products like cosmetics, medications, and some foods that are sensitive to UV light. These films contribute to product quality and shelf life by effectively shielding UV radiation.

Gas Barrier Properties of Volatile Substances

Some products emit volatile compounds, such as flavours or chemicals, that can contaminate surrounding products or the container itself. Multilayer coextruded films overcome this issue by including gas barrier layers. Polyvinylidene chloride (PVDC) is well known for its gas barrier qualities.

PVDC, when utilised as a barrier layer, provides an effective barrier against gases such as smells and solvents. By confining these volatile compounds within the package, the film preserves the product’s natural properties while also preventing contamination of surrounding products.

structural integrity and mechanical strength

Aside from barrier qualities, multilayer coextruded films provide increased structural integrity and mechanical strength. The use of various polymers with diverse qualities enables manufacturers to tailor the film to suit packaging requirements. Layers of high-density polyethylene (HDPE) can give puncture resistance, whilst layers of linear low-density polyethylene (LLDPE) add flexibility.

This structural design ensures that the package can resist handling, shipping, and storage while maintaining its barrier qualities. Whether it’s protecting fragile devices during shipment or keeping food packaging intact on shop shelves, the mechanical strength of these films is vital to their effectiveness.

Multilayer coextruded films represent the pinnacle of current packaging technology, providing a comprehensive solution for improving barrier qualities. These films provide superior barriers against oxygen, moisture, light, UV radiation, and volatile chemicals by strategically combining several polymer layers. They also provide outstanding structural integrity and mechanical strength, ensuring that packed products stay fresh, safe, and intact throughout their lifecycle. As businesses seek higher requirements for product protection and preservation, multilayer coextruded films demonstrate innovation in packaging materials.

Understanding the precise design and functionality of these films allows producers to make more educated decisions about the best packaging solutions for their products. As polymer science research and development progresses, we may expect more breakthroughs in multilayer coextruded films, pushing the frontiers of what packaging technology can do.

多層共押出しフィルムは、バリア特性、強度、汎用性などの優れた特長を併せ持つため、現代のパッケージングの基礎となっています。