How to apply high barrier packaging film technology in food packaging 1

With the improvement of living standards and the enhancement of health awareness, consumers are increasingly demanding higher food quality and safety. Traditional packaging materials often fail to effectively prevent the intrusion of substances such as oxygen and moisture into food, leading to spoilage, oxidation, and affecting its taste and nutritional value. The emergence of high-barrier packaging film technology provides a new solution for food preservation and safety. It not only effectively extends the shelf life of food but also maintains its color, aroma, and taste, offering strong support for food storage and transportation. In this issue, we will detail the principles of high-barrier packaging film technology and its applications in food packaging.

Principles of High-Barrier Packaging Film Technology

High-barrier packaging films refer to packaging materials with excellent barrier properties against gases such as oxygen, water vapor, carbon dioxide, and aromas. The principle mainly involves forming a dense film through special material structures and production processes to prevent the penetration of external gases and substances.

For example, some high-barrier packaging films adopt a multi-layer composite structure, combining layers of materials with different properties. For instance, high-barrier materials such as polyvinylidene chloride (PVDC) and ethylene-vinyl alcohol copolymer (EVOH) are used in the middle layer, while materials with good heat-sealing properties and mechanical strength, such as polyethylene (PE) and polypropylene (PP), are used for the outer and inner layers, thereby achieving efficient barrier protection for food. The following are detailed introductions to several key technological principles and effects:

High Crystallinity and Dense Molecular Structure

Principle: Some polymer materials, such as polyethylene (PE) and polypropylene (PP), can form highly crystalline structures through processing techniques. High crystallinity means that molecular chains are arranged more tightly and orderly, reducing intermolecular gaps and thereby limiting the passage of gases and water molecules.

Effect: The higher the crystallinity, the better the barrier properties of the material.

Strong Polar Groups

Principle: Introducing strong polar groups, such as hydroxyl (-OH) and carbonyl (C=O), into polymer molecular chains can enhance intermolecular interactions, forming hydrogen bonds, etc., thereby reducing the free volume between molecular chains and hindering the diffusion of gases and water molecules.

Effect: The presence of polar groups can significantly improve the barrier properties of the material, particularly against polar gases such as water vapor.

Surface Coating Technology

Principle: Coating a dense barrier material, such as a metal coating (aluminum), metal oxide coating (aluminum oxide, silicon oxide), or diamond-like carbon coating (DLC), on the surface of a polymer substrate can form a physical barrier, effectively preventing the permeation of gases such as oxygen and water vapor.

Effect: The density and thickness of the coating material determine the quality of the barrier performance. For example, aluminum coatings are widely used in packaging requiring high barrier properties due to their extremely low permeability; aluminum oxide coatings offer both transparency and good barrier properties, making them suitable for food and pharmaceutical packaging with high aesthetic requirements.

Polymer Blending Technology

Principle: Blending two or more polymer materials to form a blend with different properties. By selecting high-barrier polymers (such as polyamide, EVOH) as the dispersed phase and controlling their morphology into high-aspect-ratio fibrous or flaky forms, the diffusion path of gas molecules can be extended, reducing permeability.

Effect: The barrier properties of the blend depend on the morphology, size, and distribution of the dispersed phase, as well as the compatibility between the dispersed phase and the matrix polymer.

Polymer Nanocomposite Technology

Principle: Introducing nano-sheet materials (such as montmorillonite, graphene, aluminum oxide nano-sheets) into a polymer matrix, utilizing the high aspect ratio and barrier effect of nanomaterials to form a tortuous path, significantly improving gas barrier properties.

Effect: The selection, dispersion state, and orientation of nanomaterials have a significant impact on the barrier properties of the composite material. Ideally, nano-sheets should be uniformly distributed and arranged perpendicular to the direction of gas diffusion to maximize the barrier effect.

Advantages of High-Barrier Packaging Film Technology

Extending Food Shelf Life

High-barrier packaging films can effectively block oxygen, water vapor, and microorganisms, preventing food oxidation, spoilage, and decay, thereby extending the shelf life of food. For example, meat products packaged with high-barrier films can have their shelf life extended to several months or even longer, while meat products packaged with ordinary films may only last a few days.

Maintaining Food Quality

High-barrier packaging films can preserve the color, aroma, and taste of food, preventing the flavor and texture from being affected by the external environment. For example, coffee packaged with high-barrier films retains its aroma well, while coffee packaged with ordinary films may gradually lose its aroma.

Improving Food Safety

High-barrier packaging films can prevent food from contamination by external pollutants, enhancing food safety. For example, the microbial count inside food packaged with high-barrier films can be effectively controlled, reducing the risk of food poisoning.

Facilitating Food Storage and Transportation

High-barrier packaging films have good mechanical strength and heat resistance, enabling them to withstand pressure and impact during storage and transportation, preventing food damage and leakage. For example, food packaged with high-barrier films can endure certain squeezing and collisions during transportation without affecting its quality and safety.

Preserving Food Freshness and Nutritional Value

High-barrier packaging films can effectively prevent the destruction of nutrients in food by external factors such as oxygen and light, thereby maximizing the retention of food's nutritional value. For example, vitamin products packaged with high-barrier films can reduce vitamin loss, ensuring their nutritional efficacy; oil and fat products packaged with high-barrier films can reduce oxidative rancidity, ensuring their nutritional value and food safety.

Reducing Food Packaging Costs

Many perishable foods rely on cold chains to maintain freshness, which increases logistics costs and energy consumption. High-barrier packaging films can extend the shelf life of food at room temperature, reducing dependence on cold chains and lowering logistics costs. For example, pasteurized milk packaged with high-barrier films can be stored at room temperature for longer periods, reducing refrigeration costs during transportation and storage. Additionally, high-barrier packaging films can reduce the use of food additives, thereby lowering production costs.

Intelligence

With the development of IoT and sensor technologies, high-barrier packaging film technology will develop towards intelligence. For example, by embedding oxygen sensors, humidity sensors, or temperature sensors in films, environmental information inside food packaging can be promptly fed back. Once there is a risk of food spoilage, alerts can be issued in time to remind consumers or producers to take appropriate measures.

High-barrier packaging film technology achieves effective barrier against gases and water molecules by utilizing various principles such as high crystallinity, strong polar groups, dense coatings, blended structures, and the barrier effects of nanocomposites, thereby extending product shelf life and maintaining product quality. These technologies can be used individually or in combination to achieve optimal barrier effects. With the continuous development of material science and processing technologies, high-barrier packaging film technology will become more mature and refined, providing safer and more efficient packaging solutions for food production, processing, and transportation.