Comprehensive Summary of 11 Types of Plastic Film Characteristics in Packaging! (Part 2)

Plastic films play a crucial role in modern packaging solutions, offering a wide range of properties and applications. In this guide, we’ll continue our in-depth look at the properties of 11 major plastic films commonly used in the packaging industry.

1. High-Density Polyethylene (HDPE) Film

HDPE film, also known as geomembrane or impermeable membrane, boasts a melting point ranging from 110°C to 130°C and a relative density of 0.918-0.965 kg/cm3. It exhibits high crystallinity and is a non-polar thermoplastic resin. HDPE is renowned for its excellent resistance to high and low temperatures, even performing well at -40°F. It offers outstanding chemical stability, rigidity, toughness, mechanical strength, tear resistance, and heat resistance. As density increases, its mechanical and barrier properties, tensile strength, and heat resistance improve accordingly. HDPE is resistant to acids, alkalis, organic solvents, and corrosion. It is typically opaque, waxy to the touch, and produces a rustling sound when rubbed or friction occurs.

2. Low-Density Polyethylene (LDPE) Film

LDPE film is characterized by its low density, flexibility, low-temperature resistance, and good chemical stability. It is resistant to acids (excluding strong oxidative acids), alkalis, salts, and possesses excellent electrical insulation properties. LDPE, commonly identified by material code 4, finds extensive use in plastic packaging bags, civil engineering, and agricultural applications such as geomembranes and agricultural films (greenhouse films, ground films, silage films, etc.). LDPE bags are soft and produce less rustling sound when rubbed compared to other films like PVC or PP.

3. Polyvinyl Alcohol (PVA) Film

PVA high-barrier composite film is created by coating a modified water-soluble polyvinyl alcohol liquid on a polyethylene plastic substrate, providing exceptional barrier properties and meeting environmental standards. Due to its high barrier properties and eco-friendly nature, PVA film has a bright market outlook, especially in the food industry.

4. Cast Polypropylene Film (CPP)

CPP film is a non-stretched, non-oriented flat extruded film produced through melt casting and rapid cooling. It offers fast production speeds, high yields, excellent transparency, glossiness, barrier properties, flexibility, and uniform thickness. CPP films can withstand high-temperature cooking (above 120°C) and low-temperature heat sealing (below 125°C), making them ideal for textile, food, and daily use product packaging. They are used as inner layer substrates in composite packaging, extending the shelf life of food products and enhancing aesthetics.

5. Biaxially Oriented Polypropylene Film (BOPP)

BOPP film, developed in the 1960s, is a transparent flexible packaging material with advantages such as low density, corrosion resistance, excellent heat resistance, high optical performance, mechanical strength, abundant raw material sources, superb printing properties, and compatibility with paper, PET, and other substrates. It offers high clarity, glossiness, excellent ink absorption, coating adhesion, high tensile strength, outstanding oil barrier properties, and low static electricity characteristics.

6. Aluminum Coating Film

Aluminum-coated films combine the properties of plastic films and metals. The aluminum coating provides light blocking and UV protection, extending the shelf life of contents and enhancing film brightness. It serves as a cost-effective, visually appealing, and effective barrier material, widely used in composite packaging for dry and puffed food products, pharmaceuticals, and cosmetics.

In conclusion, understanding the unique properties and applications of these 11 types of plastic films is crucial for selecting the right packaging solutions across various industries. Each film type offers distinct advantages, from high barrier properties to excellent mechanical strength, catering to diverse packaging needs.