Post-consumer resin is a recycled resin pellet obtained from processing the existing plastic products.

PCR manufacturing involves processes as shown below:

Processing/recycling plastic sounds thrilling but it has its own challenges. These are:

1.    Collection

In a highly populated and diversified world, it is easy to find abundant plastic waste but difficult to collect it for recycling. There are established ways for collecting and dispatching it to factories for processing into PCR.
First, setting up plastic recycling centres at every consumer market location makes people aware of such recycling centres. Organizations can also set up reverse vending machines, where people are paid for returning plastic waste.
Second, collection workers / environmentalists gather tons of plastic bottles and waste from dumping grounds or landfills and sell it to industries for recycling. This task is now being done by machines in developing cities.
Third, educating the consumer to segregate wet and dry waste at their residence so that public or private organizations can easily collect that waste and dispatch it for recycling at specific processing plants.

2.    Contamination

To segregate plastic from waste, it is important to understand what the outcome of segregation is. Plastic is collected from different locations where people use various types of products. These products are in combination with diverse other materials when collected. For example, PP caps, PET bottles, PS products, metal components, wooden components, and many more.
Even after segregating as per the grade, micro particles of unwanted materials such as wood, metals, and other plastics are present. Different coloured products of the same grade is another issue with this stage. Time and cost factors make colour-based separation nearly impossible.
Let us understand the process with an example. The most common commercial plastic is PET (Polyethylene Terephthalate). All soft drink and water bottles are made from it. Recycling PET is challenging as different grades are used for soft drinks, juices, and water bottles.
Difference in colour and material properties (viscosity for example) of PET bottles as well as presence of  PET containers with varying features makes it a challenge to recycle plastic in bulk. The difference in intrinsic viscosities of various materials may create recycled plastic with varying intrinsic viscosities in different sections. Intrinsic viscosity is the measure of a solute’s contribution to the viscosity of the solution. 

Other additives that contaminate the batch are microscopic particles of sand, glass, plastics, or metals. These get processed with the main plastic products and the PCR obtained contains their micro particles. Small particles/ contaminants produce black spots or a tear or flow pattern during moulding of that PCR.

3.    Variation:

Although PCR is usually obtained from plastic of the same grade, contamination or presence of other grades which gets processed during recycling alters material properties. For example, PE may be present in PP during recycling. It is difficult and expensive to segregate these. Thus, PCR obtained by recycling 100% PP usually has 5-20% PE, which makes the final product softer/ flimsy. Moreover, the percentage of PE content in PP-based PCR varies from batch to batch. 
To control the pack’s properties, businesses mix PCR with virgin resin in variable percentages based on the pack’s quality requirements. For example, 25% PCR – 75% Virgin, 50% PCR – 50% Virgin, etc. 

For moulding PCR, the processing conditions are somewhat different from moulding a virgin resin of the same grade. For example, injection pressure is usually different in PCR than in virgin material because of PCR’s inconsistent viscosity. Sometimes, even hold pressure must be altered.
Another issue is the appearance of the PCR product. Natural appearance of PCR is greyish. When PCR is moulded, the product has a greyish appearance. To obtain non-greyish shades, a solid colour, the master batch/pigment is added in PCR resin. The quantity of the master batch depends on required shade depth and part geometry. To obtain a dark blue colour, you have to add more master-batch than what you add in for virgin resin. Hence, with PCR, it is difficult to obtain bright or translucent colours without the right expertise. 

4.    Investment:

Although eco-friendly, some companies have to push their boundaries occasionally in-order to use PCR instead of virgin resin. A production company would have to invest in certain aspects of its production infrastructure to be able to use PCR.
A PCR silo is a basic additional requirement. PCR properties vary from batch to batch. To avoid final product quality fluctuations, a company must order and store PCR in large quantities and store it in a silo. An additional silo would be a large investment for some companies. 
High master batch requirement in PCR compared to virgin resin would also increase the per piece cost price. When virgin resin is to be mixed/blended with PCR, a gravimetric blender has to be installed for uniform mixing. 

EIPL is an expert in Sustainable product design and development.

Our Team provides Sustainable solutions right from product design, redesign, or innovation to implementation, and from the prototype phase to its industrial tool qualification. Our skilled and highly experienced team ensures utilization of up-to date technical capabilities and project management techniques in delivering the projects for market launch. We have several years of experience in implementing post-consumer resin (PCR) in production at optimized costs by design of the existing packaging products. This has given us an edge as we help clients rapidly attain a sustainability tag. Rigorous follow ups and data accumulation service is also provided for every project.

Moreover, we extensively assist in management and execution of R&D prospects for qualifying Dimensional, Functional and Ergonomic aspects of a product which accelerates the project timeline. We provide a detailed analysis of the process capabilities to ensure the compatibility of PCR grade packaging with Virgin grade packaging.

Our supply chain expertise has been extremely helpful to our clients in optimal relocation of their assets in relation to their suppliers. A thorough check of the vendor’s compatibility, plant’s design, supply chain documents, quotation, etc. is carried out for successful relocation.

We ensure dedicated resources for smooth communication over the course of the projects. Effective communication skills and people management are our key attributes to connect people across the globe for successful project delivery. EIPL promises excellent value addition, execution of responsibilities, and fully reliable services.

Our team has a global reach in injection moulding. We have acquired vast knowledge and experience, over last 15 years of working with global leaders of industries in India, and 42+ other countries.

Connect with us on www.efficientinnovations.in to know more!

Article by

Darshak Mehta

Project Manager

EIPL