Plastic recycling refers to the process of recovering waste or scrap plastic and reprocessing the materials into functional and useful products. This activity is known as the plastic recycling process. The goal of recycling plastic is to reduce high rates of plastic pollution while putting less pressure on virgin materials to produce brand new plastic products. This approach helps to conserve resources and diverts plastics from landfills or unintended destinations such as oceans.

Plastics are durable, lightweight and inexpensive materials. They can readily be molded into various products which find uses in a plethora of applications. Every year, more than 100 million tons of plastics are manufactured across the globe. Around 200 billion pounds of new plastic material is thermoformed, foamed, laminated and extruded into millions of packages and products. Consequently, the reuse, recovery and the recycling of plastics are extremely important.

An Overview of Plastic Recycling

There are six common types of plastics. Following are some typical products you will find for each of plastic:

What Plastics Are Recyclable?

The Need for Recycling Plastic

Currently, only PET, HDPE, and PVC plastic products are recycled under curbside recycling programs. PS, PP, and LDPE typically are not recycled because these plastic materials get stuck in the sorting equipment in recycling facilities causing it

PET

LDPE

LDPE

Phenolic

HDPE

LDPE

PET

LDPE

SBR

HDPE

ABSPVC

PP

Beverage bottlesMilk/Water bottles

Shopping bagsBattery cases

Circuit boardsMultilayer film

Detergent bottles

Greenhouse films

Beverage bottlesAppliance housingAutomobile tiresMulch film

Photographic film

Paper receipts, printing ink, food scraps

Paper, glue, surfactants, bleach, white spirit

PVC,green PET, AI, water, glue, oligomers

Silver halides, gelatin, caustic residues

Ethylene vinyl alcohol, polyamide, ionomerCu, tetrabromobisphenol A

Insecticides, soil, Ni, oxidation products

Soil (up to 30%), iron (up to 3% in soil)

PP, milk residue, pigments, paper,EPS,cork

Steel wire, fiber, oil extender

PET, PE, paper, Al foil, PP

Pb, Cu, acid, grease, dirt

Polybrominated flame retardants

Polymer ContaminationRecycle source

Another notable innovation in plastic recycling has been in finding higher value applications for recycled polymers in closed-loop recycling processes. Since 2005, for example, PET sheets for thermoforming in the UK can contain 50 percent to 70 percent recycled PET through the use of A/B/A layer sheets.

Step One: Sorting plastics automatically or with a manual sort to make sure all the contaminants are removed from the plastic waste stream.

Most plastic recycling facilities use the following two-step process:

The Latest Advances in Plastic RecyclingOngoing innovations in recycling technologies have made the plastic recycling process easier and more cost-effective. Such technologies include reliable detectors and sophisticated decision and recognition software that collectively enhance the productivity and accuracy of automatic sorting of plastics. For an example, FT-NIR detectors can run for up to 8,000 hours between faults in the detectors.

Step Two: Melting down plastics directly into a new shape or shredding into flakes then melting down before being finally processed into granulates.

Recently, some EU countries including Germany, Spain, Italy, Norway, and Austria have begun collecting rigid packaging such as pots, tubs, and trays as well as a

to break or stop. Lids and bottle tops cannot be recycled as well. “To recycle or Not to Recycle” is a big question when it comes to plastic recycling. Some plastic types are not recycled because they are not economically feasible to do so.

Every hour, Indian use 2.5 million plastic bottles, most of which are thrown away.About 9.1% of plastic production was recycled in the U.S. during 2015, varying by product category. Plastic packaging was recycled at 14.6%, plastic durable goods at 6.6%, and other non-durable goods at 2.2%. Currently, 25 percent of plastic waste is recycled in Europe.Americans recycled 3.14 million tons of plastics in 2015, down from 3.17 million in 2014.Recycling plastic takes 88% less energy than producing plastics from new raw materials.

Plastics account for 10% of total global waste generation.

Some Quick Plastic Recycling Facts

Plastics can take hundreds of years to degrade

The energy saved from recycling just a single plastic bottle can power a 100 watt light bulb for nearly an hour.

The plastics that end up in the oceans break down into small pieces and every year around 100,000 marine mammals and one million seabirds get killed eating those small pieces of plastics.

The Plastic Recycling ProcessThe simplest of plastic recycling processes involves collecting, sorting, shredding, washing, melting, and pelletizing. The actual particular processes vary based on plastic resin or type of plastic product.

Currently, around 50% of plastics we use are thrown away just after a single use.

The recovery and recycling of post-consumer flexible packaging is a problem. Most material recovery facilities and local authorities do not actively collect it due to a lack of equipment that can efficiently and easily separate them.

limited amount of post-consumer flexible packaging. Due to recent improvements in washing and sorting technologies, the recycling of non-bottle plastic packaging has become feasible.

Oceanic plastic pollution has become a recent flashpoint for public concern. Ocean plastic is expected to triple in the next decade, and public concern has prompted leading organizations around the world to take action towards better plastic resource management and pollution prevention.

Plastic recycling faces many challenges, ranging from mixed plastics to hard-to-remove residues. The cost-effective and efficient recycling of the mixed plastic stream is perhaps the biggest challenge facing the recycling industry. Experts believe that designing plastic packaging and other plastic products with recycling in mind can play a significant role in facing this challenge.

Looking Ahead

Challenges for the Plastic Recycling Industry

Recycling is critical to effective end-of-life plastic management. Increasing recycling rates have resulted from greater public awareness and the increased effectiveness of recycling operations. Operational efficiency will be supported by ongoing investment in research and development.

Recycling of a greater range of post-consumer plastic products and packaging will further boost recycling and divert more end-of-life plastic wastes from landfills. Industry and policymakers can also help stimulate recycling activity by requiring or incentivizing the use of recycled resin versus virgin plastics.

5.PACE-PET Packaging Association for Clean Environment

1.MSMECCII-MSME Chamber of Commerce and Industry of India

Plastic recycling industry associations are the bodies responsible for promoting plastic recycling, enabling members to build and maintain relationships among plastic recyclers, and lobbying with government and other organizations to help create the best possible environment for the plastic recycling industry.

8.Plastics Recyclers Europe (PRE)

2.RF-Recycling Foundation, Mumbai

Major Plastic Recycling Industry Associations

6.RACE-

4.APRA-All India Plastic Recyclers Association

9.Institute of Scrap Recycling Industries (ISRI)

3.MRAI-Materials Recycling Association of India, Mumbai

7.The Association of Plastic Recyclers

In the plastic industry, in terms of volume, polyethylenes are the largest group, followed by PVC (Poly vinyl chloride) in the second place.

Different Post Consumer Plastics for Recycling

HDPE (High density Polyethylene) products:

Generally available in bales, low cost.

Products: milk jugs and detergent bottles. High-density polyethylene - almost as dense as water, natural in colour, transparent, white, without any pigment. During recycling any colour can be mixed.

Process of recycling is very simple - Grind into small flakes approx. 1 cm., wash, float and remove heavy contaminant, dry the clean flakes in a stream of hot air, pack in boxes - ready for sale.

Reheat the flakes, add pigments of choice, colour and run through a pelletizer. By using injection moulding presses new products can be made out of the little beads that may be formed in the process of pelletizing.

End uses: Pipes, lumber, flowerpots, trashcans, and non-food application bottles.

LDPE available in bales - low cost. Chemically similar to HDPE but less dense and more flexible., e.g. Polyethylene films used for plastic bags and in grocery sacks.

End use - Plastic trash bags grocery sacks, tubing, agricultural films and lumber.

PET (Poly Ethylene Terephthalate)

Process is similar to HDPE, and special grinders are used when thin films are required.

A thin strong polyester film, extremely tough. Used for softdrink and water bottles, jars, clamshell packages like cooking containers or trays etc.

LDPE (Low Density Poly Ethylene)

Process: - Similar to the process for Polyethylene. Sort out based on colour, grind & wash. PET sinks in the wash water when plastic caps and labels will float. The clean flake is dried and often repelletized.

End use: Largest usage is in Textiles. Carpet companies often use 100 % recycled resin to manufacture Polyester carpet in different colours and textures, fibre filling for pillows, quilts and jackets clear sheets or ribbon for VCR and audio cassettes. A good quantity goes back into the bottle market. Cost varies widely with supply.

Advantages: Easy to clean, Water proof and resistant to corrosion.

PVC can be compounded with variety of additives to make wide range of flexible and rigid forms and hence versatile. PVC is a universal polymer because it can be processed by various techniques like calendering, extrusion, injections, moulding and plastosol. Physical chemical, weathering properties of PVC are excellent.

End uses: - Pipes, Profiles, Floor coverings, cable insulation, roofing sheets, packaging foils, bottles and medical products, car interiors.

PVC (Poly Vinyl Chloride):

Ÿ Primary Recycling – conversion of waste plastics into products having performance level comparable to that of original products made from virgin plastics.

PVC is a versatile and universal polymer, low cost.

Recycling of Plastics: Indian Context

Recycling of Plastics has been classified into 4 main categories:

Ÿ Quaternary Recycling – the process of recovering energy from waste plastics by incineration.

Ÿ Sizing / Chipping.

Ÿ Collection Segregation.

Ÿ Secondary Recycling – conversion of waste plastics into products having less demanding performance requirements than the original material.

The present article deals with the first two categories of Recycling.

Ÿ Extrusion / Palletisation

Ÿ Tertiary Recycling – the process of producing chemicals / fuels / similar products from waste plastics.

Ÿ Cleaning & Drying.

Ÿ Fabrication into end Product.

Each of the above steps involves a series of operations.

Ÿ Agglomerating / Colouring

The process of recycling of waste plastics into products of varying usefulness mostly involves the following essential steps:

Collection / Segregation:

The basic principle of plastic / polymer processing is that the polymeric materials under process are required to be compatible with each other, if more than one type of plastic materials are involved..

Certain polymeric materials are compatible with each other at all proportions.For example LDPE and Lldpe are generally compatible to each other at all proportions.

However, it is to be remembered that even differing molecular weight variety of the same polymer may not be compatible for useful purpose. For example phase separation may occur if a high molecular weight (low Melt Flow Index) grade of LDPE (e.g. heavy duty film grade) is processed with a very low molecular weight (high Melt Flow Index) grade of LDPE (e.g. high flow Injection Moulding grade).

However in the Indian Context, this separation or segregation process, in many cases, are done by manual process utilizing the availability of cheap and expert labour force.In case the waste is contaminated with embedded metals, proper method of separating the metals / other contaminants, is required.

Cleaning & Drying:

Generally, Industrial waste does not require significant cleaning operation, whereas, post-consumer waste requires proper cleaning.

For drying, a suitably designed drier is used.

Many industries situated out side the metropolises, use open space for natural drying of the cleaned waste.

Sizing / Chipping:

The scale of cleaning depends on the type of waste.

Whenever a cleaning operation is involved, it is to be ensured that the water or any other cleaning material used, should be discharged after ascertaining that the discharge does not contain any objectionable substance. A proper Treatment Device may have to be deployed – like a water treatment plant / effluent treatment plant.

The advanced technology of separating / segregating different types of waste plastics involves ‘Floatation Process’. In this process the property of the varying densities of different plastics is made use of for segregating different types of plastics.

The cleaned plastics waste is then required to be properly sized so that those may be fed into the extruders for

Agglomerating / Colouring

The type and size of the Extruder depend on the type and volume of the plastics waste.

Extrusion / Palletisation

In the next operation the sized plastics waste is mixed with colour master batch in high-speed mixers / agglomerators and the output is ready for extrusion into pellets.

Finally the reprocessed plastics granules are used as raw material for producing end products using similar fabrication machines like Injection Moulding / Extrusion etc., depending upon specific requirement.

Fabrication into end Product

During this process, attention is required to separate any powdery material from the sized / chipped plastics.

This is the most important part of the process wherein the sized / chipped plastics are plasticised and regranulated to make the plastics material ready for fabrication next.

processing and palletizing. The sizing operation depends on the type and shape of the waste plastics.