The ability of additives added to the PVC film

Polymer preparation consists of a series of processing steps conducted on the incoming polymer to increase its process-ability range and to satisfy the requirements of the finished product. Since unmodified PVC resins are virtually unprocessable, the need for additive modification is indispensable. Additive modification is also needed to enhance polymer properties and to ensure the service life of the end product, hence increasing its utility, like PVC Film and PVC Sheet.

Some additives are used to enhance polymer process-ability:

• Heat stabilizers
• Lubricants(without lubrication, melted PVC sticks to hot metals), external and internal
• Processing aids, mainly used to increase "hot melt strength" while reducing melt fracture, allowing processors to extrude or calender at faster rates

Other additives are used to enhance mechanical and electrical properties:

• Impact modifiers (Izod impact of unmodified PVC is about 0.6 ft lbf/in.,inadequate for most applications)
• Heat distortion improvers
• Electrical insulation boosters

In addition, additive modification is used to:

Improve outdoor service life (weather ability): pigments such as titanium dioxide, zinc oxide, ultraviolet (UV) light absorbers, and special stabilizers

Improve compound costs-fillers and extenders, such as calcium carbonate and fine-particle hydrated alumina

Achieving a balance of these additives to obtain adequate processability and heat stability, satisfactory properties and service life, compliance with the various government regulations, and an acceptable level of performance versus cost is mainly the responsibility of the compound formulator.