Plastic Films and Their Forming Methods

Plastic films generally refer to flat and flexible plastic products with a thickness of less than 0.25 mm. Soft planar materials with a thickness above 2.0 mm and hard planar materials with a thickness above 0.5 mm are termed plastic sheets, while soft planar materials with a thickness between 0.25 mm and 2.0 mm and hard planar materials below 0.5 mm are referred to as plastic sheets (or "plates"). Thus, there is no fundamental distinction between plastic films and sheets; the difference lies solely in thickness. This classification varies by national standards.

Plastic films are widely used across industries, agriculture, and daily life. For example: Packaging films are extensively utilized for moisture, dust, and corrosion resistance in food, light industry, textiles, chemicals, and other sectors.

Agricultural films play significant roles in seedling cultivation, greenhouse construction, wind protection, thermal insulation, moisture retention, and pest and disease prevention.

As a result, plastic films are one of the highest-yield plastic products, with numerous varieties, and represent a major category in extrusion molding. In some countries, plastic films account for approximately one-third of extrusion products and 15%–20% of total plastic production. The production

methods for plastic films can be broadly categorized into: Extrusion methods (including extrusion blow molding, extrusion stretching, and extrusion casting). Calendering methods. Solution casting methods. Some scholars classify plastic film production into four categories: extrusion, stretching, calendering, and solution casting.