Processing of Vinyl Plastic
Some of the main processes include extrusion, calendering, injection molding, stretch blow molding, etc.

The intimate mixing of the PVC resin with its associated additives is necessary prior to converting into a thermoplastic melt. Thermal stabilization is required for processing rigid PVC, otherwise material may decompose during processing. Also, spray, blush & peel are very common molding defects associated with rigid PVC…Learn systematic methods to solve routine molding issues!
PVC is sensitive to the thermal history and the window of processing temperatures is quite small. Drying before processing is highly recommended, moisture rate should be lower than 0.3%
Drying before processing is highly recommended for plasticized PVC, moisture rate should be lower than 0.3%.

PVC and 3D Printing

PVC has largely been overlooked as being suitable for 3D printing, and the new developments are opening the way for PVC into the growing world of additive manufacturing. For example, Chemson Pacific Pty Ltd, a Vinyl Council of Australia member, demonstrated a world-first for 3DVinyl™ PVC material by 3D printing a giant flower vase using a pellet-fed 3D-printer.

Bonding Methods for PVC

PVC material can be bonded using different joining techniques to fabricate PVC into the finished article. All welding techniques involve the application or generation of heat to soften the material whilst pressure is applied simultaneously. Bonding techniques, involving adhesives, are also common.

Recyclability and Toxicity of PVC

Products made from PVC are 100% recyclable and can be identified as recycling code #3.

Adopting an appropriate recycling pathway for PVC is of both an economic value and an environmental benefit. Key methods for PVC recycling include:

·         Mechanical Recycling – Mechanical recycling refers to recycling processes where PVC waste is treated through shredding, sieving and grinding. Depending on the composition, the quality of the recyclates can vary a lot. After mechanical separation, grinding, washing and treatment to eliminate impurities, it is reprocessed using various techniques (granulated or powder) and reused in the production. "High quality" can be re-used in the same types of applications, whereas "low quality" recyclates from can only be used into products made from other material.

·         Chemical Recycling – Chemical recycling processes break up polymer into monomers (used to produce new polymers) or other substances (used as starting materials in processes of the basic chemical industry. The Chlorine is set free in the form of HCl that can be re-used or neutralized to form various products. Stabilizers containing heavy metals mostly end up in solid residues that will most probably have to be landfilled.

·         Feedstock Recycling – It involves (usually) thermal treatment of the PVC waste stream with recovery of hydrogen chloride that can then be returned to the PVC production process or used in other processes.

Recycled PVC can be used to produce packaging, film and sheet, loose-leaf binders, pipes, carpet backing, electrical boxes, cables and more.

The industry is working with the regulatory authorities to ensure that recycling activities remain sustainable while complying with the regulatory regime.

Presence of chlorine content and use of additives such as plasticizers bought PVC under scrutiny for a number of years. Concerns have been raised at regular intervals, in several regions, regarding the possible negative impact of phthalates on the environment and human health. However, on further investigations and studies certain phthalates are now confirmed safe for use in current applications.

Similarly, Europe has phased out use of lead-based stabilizers in vinyl compounds due to their classification as reprotoxic, harmful, dangerous for the environment and their presence (heavy metal) causing issues in waste management strategies.