Polystyrene film suitable for fresh food packaging

[Chinese Packaging News] Polystyrene (PS) film is commonly used in packaging due to its unique properties. Its general thickness ranges from 0.004 to 0.1 mm, making it a lightweight and flexible material. Unlike some other plastics, PS film is not brittle when unstretched, which makes it ideal for biaxial stretching processes. This treatment enhances the film's mechanical strength and improves its barrier properties against moisture and gases. PS film is known for its high transparency, excellent dimensional stability, and non-toxic nature, making it a safe choice for food packaging. It is also relatively breathable, which suits its use in packaging fresh products that continue to respire during storage, such as fish, meat, and vegetables. One of the key advantages of PS film is its ease of stretch orientation. It starts to soften at around 100°C, and even with high melt viscosity, it can be stretched effectively up to 130°C. The biaxial stretching process typically involves either a bubble or flat-film method, both of which contribute to improved performance and appearance. Additionally, PS film is well-suited for thermoforming applications, allowing it to be shaped into various forms like trays, bowls, and containers. In such cases, the film is usually thicker than 0.100 mm to ensure structural integrity. Another notable feature is its heat-shrinkable property. PS film can shrink by up to 45-55% when exposed to temperatures between 70°C and 120°C, making it ideal for tight, protective packaging. Due to its clarity and optical quality, PS film is often used as a window material in packaging, providing visibility for the product inside while maintaining a secure seal. Whether used in food packaging, retail displays, or industrial applications, PS film remains a versatile and widely utilized material in the packaging industry.