Wrapping film, also known as stretch film or heat shrink film, was the earliest domestically produced PVC wrapping film using PVC as the base material and DOA as a plasticizer with self-adhesive properties. Due to environmental issues, high costs (relatively high PE ratio compared to aluminum-plastic vacuum bags, with less unit packaging area), and poor stretchability, PE stretch film was gradually phased out when it was produced domestically in 1994-1995. PE stretch film was first made of EVA as a self-adhesive material, but its cost was high and it had a taste. Later, PIB and VLDPE were developed as self-adhesive materials, and LLDPE is now the main substrate, including C4, C6, C8, and metallocene PE (MPE).
早期LLDPE拉伸膜以吹膜为多，从单层发展到二层、三层；以流延法生产LLDPE拉伸膜为主，其流程见下图，这是因为流延线生产具有厚薄均匀、透明度高等优点，可适用于高倍率预拉伸的要求。由于单层流延做不到单面粘，应用领域受到局限。单、双层流延在材料选择上没有三层流延的广，配方成本也高，所以还是以三层共挤的结构较为理想。优质的拉伸膜应具有透明度高，纵向伸长率高，屈服点高，横向撕裂强度高，穿刺性能好等特点。
