PVC heat shrink film process parameters

PVC heat shrink film Melting Temperature:

The melting temperature is a very important process parameter when processing PVC, if this parameter is not appropriate will lead to material decomposition problems. the flow characteristics of PVC is quite poor, its process range is very narrow. In particular, large molecular weight PVC materials are difficult to process (lubricants are usually added to improve the flow characteristics of such materials), so small molecular weight PVC materials are usually used.

The PVC heat shrink film is quite low, typically 0.2 to 0.6%. Polyethylene films are generally made by both blow molding and casting processes.Blow-molded PE film is made from blow-molded grade PE pellets by blow-molding machine, which is widely used because of its lower cost.Cast polyethylene film has a uniform thickness, but is rarely used today due to its higher price.Low-density polyethylene film is a semi-transparent, glossy, softer texture film with excellent chemical stability, heat sealability, water and moisture resistance, freezing resistance and can be boiled. Its main drawback is the poor barrier to oxygen, commonly used in composite flexible packaging materials, the inner layer of the film, but also widely used, the amount of a plastic packaging.

Low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE) as raw materials, the use of blow molding method to prepare a heat shrink film. The effects of raw material formulation, mold blowing ratio, PVC heat shrink film blowing machine draft ratio, extrusion temperature and film bubble cooling time on the mechanical properties and transparency of polyethylene heat shrinkable film were investigated.

PVC materials in actual use often add stabilizers, lubricants, auxiliary processing agents, color, impact resistance and other additives. Selection of different resins and formulations, can produce different mechanical strength and functionality of PVC heat shrink film, can be used for lower strength, commodity weight smaller inner packaging, can also be used for higher strength requirements of containers with mechanical products, construction materials and other transportation packaging (outer packaging).