Imagine the supermarket shelves filled with products, each protected by thin, transparent packaging that silently influences both our lives and the environment. This seemingly insignificant material is plastic film. But how is it manufactured? What types exist? And how should we view its relationship with the environment?

According to Japanese Industrial Standards (JIS), plastic films are defined as plastic membrane materials with thicknesses below 0.25 millimeters. While no strict regulations exist, they're generally recognized as flexible and easily bendable. As common polymer materials, plastic films permeate nearly every aspect of modern life—from food packaging to medical devices.

Producing plastic films requires precise process control to ensure uniform thickness. Two primary manufacturing methods dominate the industry:

This method melts solid plastic raw materials, feeds them quantitatively through an extruder into molds, then cools and solidifies the output to continuously produce films with identical cross-sectional profiles. The technique enables efficient production of various plastic film specifications.

This process extrudes molten plastic through annular dies to form tubular film blanks, then inflates them with air for expansion and cooling. Advantages include high production efficiency and the ability to manufacture wide-width films. The tubular formation keeps inner surfaces contamination-free, making it ideal for sterile applications like medical IV bags and food packaging.

This alternative extrudes molten plastic through slit dies to create sheet-like film blanks for rapid cooling. Compared to blown film, cast extrusion yields films with superior thickness uniformity and transparency. It's also better suited for producing thicker films.

Crude oil serves as the primary raw material. The complex refining process transforms petroleum into usable plastic materials:

• Oil Refining: Crude oil—a mixture of organic molecules—undergoes distillation at refineries to separate naphtha (boiling range: 35-180°C). Thermal cracking then decomposes naphtha into smaller molecules like ethylene, propylene, butadiene, and aromatic hydrocarbons (benzene, toluene, xylene)—foundational materials for plastics and petrochemicals.
• Polymerization: Connecting small molecules (ethylene, propylene) into long-chain polymers yields common plastic materials like polyethylene (PE) and polypropylene (PP), which are further processed into various film types.

With crude oil being finite, does plastic film production negatively impact the environment? The answer requires nuanced examination:

• Consumption Share: In Japan, plastics constitute merely 3% of total oil consumption, with about half used for plastic films. The remaining 97% primarily fuels energy production, suggesting environmental efforts should prioritize larger consumption sectors.
• Functional Necessity: During the COVID-19 pandemic, plastic medical supplies saved countless lives. Food vacuum packaging extends shelf life, reducing waste—Japan generated 4.72 million tons of food waste in 2022 alone. Plastic films minimize resource consumption across production, transportation, and disposal cycles. Their lightweight nature also reduces transport fuel usage compared to glass or metal alternatives.
• Innovation Potential: Emerging technologies enable more sustainable plastic solutions, including bio-based and biodegradable variants. Enhanced recycling rates can mitigate environmental pollution—chemical recycling technologies, for instance, transform waste plastics into new raw materials for circular economies.

The industry actively pursues sustainable development through:

• Bio-based Plastics: Derived from renewable resources like plants or microorganisms, these reduce petroleum dependence and carbon emissions.
• Biodegradable Plastics: Designed to decompose into CO₂ and water under specific conditions, they alleviate environmental accumulation.
• Chemical Recycling: This advanced process handles diverse plastic waste streams, yielding higher-quality recycled materials than traditional mechanical methods.

Plastic films remain indispensable in modern society. While their production and use present environmental challenges, technological innovation and policy guidance can enable sustainable utilization. The path forward requires balanced understanding of plastic's benefits and limitations, coupled with committed development of eco-friendly alternatives.