CIF Looks at the Pros and Cons of Black Plastic in Residential Recycling

CIF Looks at the Pros and Cons of Black Plastic in Residential Recycling

Have we become diametrically opposed to Henry Ford’s “you can have any colour as long as it’s black” proclamation?  When it comes to recycling household plastics packaging the answer is a resounding “maybe”.

Black plastics, or plastics that are black, have been making headlines in Ontario recently. Major municipalities have moved to eliminate black plastics from curbside collection programs citing processing issues and lack of markets as the driving forces. Other communities continue to accept black plastics at curbside. The result is confusion at all levels including consumers, vendors, MRF operators and reprocessors.  This article seeks to break down the rumours and legitimate issues.  Black packaging (in particular food packaging) exists because it has high consumer appeal and carbon black is a low cost colourant. Functionally, carbon black is unsurpassed at protecting plastics against degradation from UV light.

“Black plastics” versus “Plastics that are black”

Black plastics carries the connotation of a separate class of plastics. The fact is that black plastics are simply a mix of the four common resins typically found in Ontario Blue Boxes: polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE) and to a lesser extent, polystyrene (PS). They are just colored black. A typical Ontario 3 – 7 mixed plastic bale container is estimated to contain between 6% – 20% black coloured plastics, depending on the season and community demographics.  Up to 75% is reported to be PP and PE which is the resin most reprocessors are particularly interested in.  Since “black plastics” is the popular term, it is used in this article with the understanding that it refers to a group of polymers with different processing characteristics and substantially diverse markets.

Is There Really a Lack of Markets?

The answer requires consideration of resins that make up the typical mix of black plastics found at the curb.  Markets for black PP and PE far outstrip the supply and in most cases materials are upcycled from disposable to durable products (e.g. automotive, housewares, drainage components).  A 2018 More Recycling [1] report estimates the annual demand for black PP in North America at 80 millions pounds (i.e., 36,288 metric tonnes).  A single European processor claims a demand of about 70,000 tonnes of black PP alone [2].  The same cannot be said for black PET where market development for recycled PET (r-PET) has not kept pace with the growth of the source packaging.  Currently there are limited markets for black r-PET such as manufacturers of black strapping and fibres.  Proprietary product development for automotive and other durable applications is in progress but, as yet, does not represent a significant market.

Processing Issues are Challenging

There is considerable mixed messaging being generated.  Some  sources have suggested black plastics are not recyclable.  This statement is not accurate.  Black plastics are recyclable but the issue is, at what cost?  The challenge in most automated  MRFs is that existing optical sorting technology is unable to sort the black plastics group into its constituent resins because the black colourant absorbs the Near Infrared (NIR) light used by the optical sorting equipment to detect polymer signatures.  This issue is recognized well beyond the Ontario borders and is the subject of a major initiative by groups such as WRAP[3] in the United Kingdom.  Specialized optical sorters using proprietary light sources and sensor technology can differentiate black plastics.  However, with typical optical sorter retrofits averaging between $750,000 to over a $1 million, the cost to retrofit Ontario’s existing MRF infrastructure would be significant to capture a relatively small amount of material (i.e., when compared to the total Blue Box tonnage) of varying value.

Black plastics can be manually “positively picked” from the belt to be recovered but even then they remain a mix of resin types with limited market appeal with no known buyers for a bale of black only plastic.  Local reprocessors have confirmed that the immediately available solution for Ontario MRF’s is to leave black plastics in a clean 3-7 bale.

Both EFS Plastics in Listowel and ReVital Plastics in Sarnia have developed processes to manage black plastics in the 3 – 7 bale and ReVital views it as an indispensable element of its processing and marketing regimes. The loss of black plastics from the mixed bale reduces the amount of product available to them, forces process adjustments, creates a shortfall in sales of black end products and reduces municipal waste diversion efforts.

Bale Quality is Crucial

A number of processors have indicated difficulty moving 3-7 bales to market. Although there can be a variety of reasons for this issue, quality and composition remain key factors in marketing any commodity.  The market data above confirms the value of a typical 3-7 bale is largely dependent upon the amount of PE and PP present.  Some processors have, in the past, been able to ‘high grade’ or remove the PP from the 3-7 bale and market both as separate commodities.  The result of high grading is a residual bale which can only be moved to domestic markets at a significant premium.

Prior to implementation of China’s National Sword legislation processors were also able to export commodity bales of varying quality.  In some instances processors were successfully marketing bales consisting of the negative run off from the belt (i.e., 3-7 plastics plus container line residue).  Those days are clearly over.  Moreover, as we all work to address existing bale quality issues MRFs generating high quality bales will continue to command better prices and have priority access to limited domestic reprocessing capacity.

Conclusions

Black plastics are likely to remain a key component of the consumer packaging mix for some time to come.  The fact that they represent such a range of resins highlights the need for leadership by producers to reduce the types of resins they use and make them more easily recyclable. In the interim municipalities are encouraged to work with their processors to understand what is required to make their bales marketable and make informed decisions about the financial implications of having these materials in their programs.

[1] End Market Demand for Recycled Plastic, More Recycling October 2017

[2] https://www.eppm.com/blogs/guest-blogs/recycling-black-plastics-real-vs-fake-news/

[3] The Waste and Resources Action Programme (which operates as WRAP) is a registered UK Charity