Tony Gaukroger, Director, Colour Tone Masterbatch
- As a masterbatch producer specialising in colour, you’ve built up an incredible amount of expertise in pigments. But how did it all start?
The plastics industry was in its infancy in the 1970’s when my career began, at that time it was far easier to move jobs to explore various specialisms – that is of course if you weren’t frightened of change! Initially I worked in a factory lab before quickly progressing to new roles from quality control to business development.
Despite sales management success for eight years with Masterplast during which it was acquired by the multinational chemical giant Hoechst, my role had become increasingly non-technical. It was time to find a new challenge, so in 1996 I decided to establish a specialist additive and masterbatch manufacturing business, Colour Tone. www.colourtone-masterbatch.co.uk
Colour Tone aimed to deliver a responsive high quality service to clients offering bespoke colours in universal, commodity and engineering polymers. But most importantly, it allowed us the freedom to find highly innovative solutions to help satisfy new emerging market needs and demands. This lead to the development of the market’s first self-colouring system for PVCu, known as Vynacol®.
In 2017 Colour Tone became a subsidiary of technical plastics compounder Luxus.
- Working with colours also led you to become interested in heat reflective pigments. What’s the connection?
With Colour Tone we could explore fresh challenges, we knew that there was no masterbatch available that could work reliably for colouring PVCu. Although universal and polymer specific masterbatches for flexible PVC has been available for years, they hadn’t consistently worked in PVCu due to inherent processing difficulties.
PVCu despite being a highly versatile material, is extremely heat sensitive and highly resistant to flow during its melt phase. Processors had to find just the right grade for their application and plant, consequently there are thousands of PVC formulations with varying additives and featuring different levels of compounding each of which asks different questions of the colouring system.
Masterbatches are made by subjecting relatively high loadings of pigments and polymer to high shear forces such as a twin screw extruder. PVCu is extremely sensitive to both heat and shear which causes the polymer to thermally degrade. Vynacol overcomes these challenges to produce effective, polymer specific masterbatches for colouring PVCu.
It was while developing colours for building and construction applications that the use of infra-red reflective colours, for heat reflective applications, first came to our attention. This was a market sector that had not been commercially explored, we were one of the first masterbatch manufacturers to research and supply them. They became known later as “Cool Plastics”.
- Is it a technology that works with all plastics?
Yes, this technology can work with any plastic, but PVCu lends itself well to numerous external construction applications.
- They were originally developed for the building and construction sector, is that correct? What kind of problems do they address?
The development originally of infrared reflective and low heat build-up pigments was to help reduce the environmental impact of heat, initially in paint coatings and later plastics. They were primarily used for cars and buildings to help reduce the need for air conditioning and improve energy efficiency.
New applications are found all the time, for instance, the same technology is used in dark coloured PP patio furniture to avoid people sitting on hot chairs in thin summer clothes. Previously dark colours were avoided and white was standard.
- How did these insights lead to your development of masterbatches that make it possible for black colours to be sorted for recycling by using near infrared technology? Because black is usually not visible, which causes huge problems when it comes to recycling the black trays used in quite a lot of food packaging.
The near-infrared (NIR) spectrography currently used by materials recovery facilities (MRFs), offers a highly efficient method of sorting mixed plastics waste by polymer type. The major limitation with this process however, is that plastic is coloured and the colourant in the packaging strongly absorbs, rather than reflects NIR, so the sorter is unable to identify the ‘signature’ from the spectrophotometer.
It was our expert understanding of how pigments absorb in the infrared spectral range gained from the development of Vynacol, that meant we were well placed to support initial ‘blue sky’ discussions with waste charity WRAP regarding the future development of infrared reflective colours.
As a result, Colour Tone was selected to support a pioneering project sponsored by WRAP back in 2011. It aimed to facilitate the development of technical solutions for the effective recovery and recycling of rigid black plastic packaging from the mixed plastics waste stream.
Its subsequent validation trial, lead to the development of a novel near-infrared reflecting colourant technology, that enabled black plastic to be made ‘visible’ for the very first time to optical sorters, since it reflected rather than absorbed NIR.
- So how do we know when something has been coloured using the right masterbatch or not? What if it has been coloured with carbon black, for example?
A plastic product designed to be NIR sortable is simply that – it is not the result of incorporating a “magic” additive that converts the material to an IR reflective plastic.
Black and coloured masterbatches that do not inhibit NIR sorting of plastics, look just like any other masterbatch. So the responsibility is placed on the component manufacturer to ensure that their product is not NIR absorbent, this requires a degree of quality assurance to prove that it is.
Integral to this process is an in-house spectrophotometer which we use to provide clients with a colour matched submission. It offers a graph displaying the percentage reflected for each wavelength across the electro-magnetic spectrum in the UV, visible and IR ranges, for the colour.
Similar to colour standards and assuming the colour is approved, it provides a reference point. Then with each batch delivery we will supply another graph of the reflected percentage of IR for comparison.
- It would seem to be a timely development, especially in view of the current focus on recycling. Have you noticed any changes in the market in response to the government’s recently announced recycling ambitions?
The issue of how to responsibly manage our plastics waste has never been higher on the consumer’s agenda than it is right now, so inevitably retailers and producers are actively pursuing sustainable solutions.
While the government’s stance on plastics recycling is welcome, if it was to take its ambitions further by ensuring that designing for ‘end-of-life’ is mandatory for plastic products, the amount of plastic being recycled would increase significantly, to the benefit of our circular economy.This approach could be introduced immediately for all new products to prepare for the introduction and expansion of kerbside collection in the future.
Our government could follow Germany’s lead, its new packaging law which comes into force in 2019 is focused on improving recycling and prevention of packaging waste. The law aims to encourage re-useable packaging with an increased recycling target set for plastics of 63% by 2022. Businesses will risk fines of up to €50,000 if they fail to comply.
- How has the response been from the packaging manufacturers to these masterbatches?
Inevitably there is increasing interest from the packaging manufacturers, also retailers and brand owners. But we have to be mindful, that they are just one of the many interested parties required to make the adoption of this technically proven NIR technology workable.
What we need is the co-operation of the wider supply chain itself from retailers, waste management companies and brand owners to recyclers, if we are to tackle not only the 1.3 billion black trays, but the many coloured ones too that are landfilled and incinerated each year.
- Pricing has been historically cited by retailers as a potential ‘barrier’ to this technology’s adoption, is this still the case?
Historically it was claimed that the price premium for NIR technology had been a ‘barrier’ to its adoption. We have recently launched a NIR black (958884) masterbatch that delivers the required eco-benefits at a competitive price, significantly reducing the ‘gap’ between this and conventional carbon black pigments at just 0.21p per tray.
- Lately there has been some consternation about additives used in the original plastic product turning up in recycled materials, which is not always a good thing. Some kinds of plasticizers and flame retardants are notorious for this. What about this technology?
There are still some applications where plastics are not recycled, simply because the use of problem additives cannot be turned off overnight. But it’s my belief that we are in a period of transition where harmful additives are effectively being designed out of the supply chain. We have seen this happen with lead stabilised PVC and heavy metal pigments used in packaging for example.
- Except for packaging, there must be plenty of other areas in which a lot of black and coloured plastics are used and where recycling targets apply. Where else do you see this technology being applied?
We are currently extending our NIR technology to support new markets, such as the management of plastics at ‘end-of-life’ from WEEE and automotive components, each of which has its own specialist requirements.
This is currently the focus of a £1.29m commercialisation project known as NIR Sort, it is co-funded by the EU Horizon 2020 research and innovation programme and supported by a consortium led by technical plastics compounder Luxus. www.luxus.co.uk
It aims to develop a range of colourants for polymers that will enable NIR sorting operations to segregate black and coloured plastics from waste streams to a level of purity that they are useable in highly engineered polymers. Since it is our belief that one day all plastic items will be recovered for recycling to make the most of what is a highly sustainable material.