Abstract
Ocean plastics is a topic often in the news currently. The main focus seems to be plastic bottles, packaging waste and other large discarded items; more recently, microplastics have been generating legislative reactions, with the proposed ban of plastic microbeads from cosmetics and personal care products. However, the paint and coatings sector also have a role to play in reducing micro-plastics from our oceans. This report discusses the scale of the problem posed by the paint industry and provides an overview of the approaches to address this issue now and in the future.
Introduction
The paint and coatings industry is important to the UK economy, contributing £2.8bn to GDP and supporting a wider £150bn supply chain; 20% of the UK’s GDP is dependent on the sector[1]. In addition, the UK is a net exporter of paints and coatings, and three quarters of the paint sold in the UK was manufactured here.
Liquid paints are comprised of three main components: polymer resins provide the film-forming properties of the paint, adhering to and protecting the underlying substrate; inorganic and organic pigments provide aesthetic properties and, in some cases, provide additional functionality in the form of UV protection and contribute to the finish of the paint film; these constituents of the final dry paint film are delivered to the substrate, suspended or dissolved in a liquid carrier that is either water or organic solvent. For architectural coatings, water-borne paints dominate solvent-borne products, with around 85% of the market share in Europe[2].
Discussions around the problem of ocean plastics are often illustrated with dramatic images of floating rubbish composed of plastic bottles and bags; lately the debate has expanded to include microplastics, small plastic pieces less than 5 mm long. These microplastics may be in the form of microbeads used in personal care products; those generated through use of a product e.g. the wearing away of tyres and the fibres released from synthetic clothing during washing; or the result of fragmentation of the larger discarded plastic items. It is widely agreed that the best way to tackle ocean plastic pollution is to address the cause of pollution, rather than cleaning up the effects and considerable attention has been focussed on reduction and recycling of the growing plastic waste generated by the packaging sector. According to data released by the UK Department for Environment, Food and Rural Affairs (DEFRA), household waste recycling rates have increased from 11.2% in 2000[3] to 45.7% 2017, with over 70% of UK packaging waste either recycled or recovered in 2017[4]. British Plastics Federation (BPF) statistics indicate that the plastic packaging recovery rate is 78%, with a recycling rate of 46%[5]. Whilst there is still room for improvement, particularly in the volume of plastics arisings in the UK (3.7 million tonnes in 2016[6]), the drive to address packaging waste generation has resulted in the UK exceeding the EU target to recycle or recover at least 60% of packaging waste; there has been little attention to-date on the environmental fate of unused, unusable waste paint.
The problem
Paints are a major contributor to marine pollution in the form of plastic microparticles abraded from coated surfaces and from the disposal of waste, unused paint. The Korea Institute of Ocean Science and Technology found that more than 90% of the synthetic particles in the sea surface microlayer off the coast of Korea consisted of polymers typical of those used as binders in paints; only 4% of particles were the more well-known polyethylene, polypropylene, and polystyrene[7]. These microparticles are particularly concerning because of their entry into the marine food chain and subsequent bioaccumulation. Whilst microplastics from abraded painted surfaces are thought to be relatively large contributors[8], there is little that the public can do directly to influence these losses. Plastic waste arising from unused paint is a different story.
The paint industry has endeavoured to make savings in resource use in the form of energy savings and waste created, resulting in reductions of 50% or more. In addition, manufacturers and retailers have made significant efforts to guide the consumer to reduce potential waste by advising on correct paint use, particularly with regards to coverage requirements. Nevertheless, there is still a substantial volume of waste paint being generated and requiring disposal. More than one million litres of waste paint is generated each week in the UK[9], much of which goes to landfill. Despite investment in community projects and take-back programmes launched by some paint manufacturers to collect waste paint for reuse and remanufacture, up to 99% of the unused paint still finds its way into waste streams[10].
Water-borne coatings are the most common overall technology for architectural coatings and the remaining solvent-based coatings continues to decline in contribution. In Europe in 2015, 85% of the 5.3 million tonnes of architectural paints were water-based systems; a similar split of waterborne and solventborne technologies can be seen in the UK decorative paint market[2]. This increase in the market demand for waterborne paint will inevitably result in an increase in waste, although education in the correct use of paint can help to mitigate the environmental impacts of increasing market demand.
Two thirds of UK Household Waste Recycling Centres (HWRCs) don’t accept paint, instead advising the public to dispose of it in residual waste, which will then go to landfill; of those that do accept paint but don’t send it to recycle or reuse schemes, landfill is the primary disposal route[11]. The estimated cost to local government of disposing of waste paint each year is £20.6 million. Paradoxically, HWRCs are not collecting paint due cost and space requirements of taking on a paint recycling service, even though sending paint to a remanufacturer or a reuse organisation in place of incineration or landfill can save local authorities disposal costs of up to 40% each year[9].
Surveys in the UK have revealed that the average household has 17 tins of part-used paint[12]; an estimated 100 million litres of paint stored in cupboards, garden sheds and garages. Decorative coatings can be stored for lengthy periods of time, but ultimately the majority of the surplus is discarded, usually during periodic clear-outs, when moving property or during house clearances. In the absence of easily accessible recycling facilities, it is feared that large volumes of liquid paint is disposed of into bins and drains.
Addressing the problem
Paint manufacturers of all sizes have demonstrated willingness to invest in paint recycling solutions, with several million pounds already invested in either commercial ventures or supporting social enterprises that collect, separate, and select unused paint for re-use and recycling. One such scheme is the Community RePaint scheme, set up in 1993 to collect and redistribute leftover paint and now solely sponsored by AkzoNobel, manufacturers of Dulux. In 2018, 65 schemes redistributed more than 300,000 litres paint to local groups, charities, and low-income families, whilst providing employment, training and volunteer opportunities to those engaged in the scheme. Crown Paint’s recycling scheme Kick Out The Can was launched in 2013, inviting homeowners to bring unwanted paint into any Crown Decorating Centre to be reprocessed, reused and recycled. In 2017, 30,000 unwanted tins were returned to Crown Decorating Centres. This scheme is run in partnership with Crown’s social enterprise partner Nimtech, providing employment opportunities for the hard to reach, and long term unemployed in the community.
Much of the waste paint requiring disposal is unsuitable for reuse. In this case, a more fundamental recycling approach is required. There are currently very few companies remanufacturing waste paints; one of these is Newlife Paints, established in 2008 to collect and reprocess waste liquid water-based paint into premium grade emulsion. Based in West Sussex, the company manufactures a range of interior and exterior paints in matt, silk and eggshell and in 32 colours. Newlife’s paints are available from trade supply stores in Sussex, as well as in selected B&Q stores; patents have also been granted to Veolia, Paint 360, and La Lorraine in Belgium. In addition, Newlife has collaborated with AkzoNobel in their ReColour scheme to remanufacture the leftover paint collected for the Community RePaint programme into a recycled product into a range of 20 colours in their remanufacturing centres in Cambridgeshire and Wirral. In 2018 67,000 litres of leftover paint was remanufactured into ReColour.
The key obstacles to increasing paint recycling in the UK include the variability of the waste, making it difficult to guarantee large quantities of consistent colour and quality. Also, there is a perception that leftover paint is lower quality than virgin material. However, one of the most significant challenges to paint recycling is regulatory and resides in the EU’s Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation. REACH requires all substances used in paint manufactured for sale in the EU to be registered; this presents a significant challenge for such a diverse range of waste products for which full knowledge is unlikely to be available.
Future directions
The way forward for waste paint reuse and remanufacture in the UK will require industry and governmental support for the PaintCare Initiative. Launched in 2015 by the British Coatings Federation (BCF), PaintCare is an industry-led project that aims to create a national scheme for leftover decorative paint in the UK, in partnership with decorative paint manufacturers, retailers, trade associations, waste management companies, local and national government, and other interested parties. A number of key points have been identified to facilitate a more integrated approach to paint recycling, including improvements to waste disposal network to make it easier for the public to recycle waste paint. The regulatory hurdles can be tackled with a review of waste handling and transportation regulations, including derogations to encourage waste recovery and closed loop systems, along with amendments to the provisions under REACH for remanufactured materials. Re-use and remanufacture may be further encouraged by provision of financial support in the form of VAT and business rate exemptions, financial support for social enterprises, charities or community-based groups involved in the collection and recycling of waste paint. An update to Government Procurement Rules, to include minimum use requirements for reused and remanufactured materials will provide much-need stimulus for the market for recycled products.
As well as outlining incentives for the collection and reuse of waste paint, a key recommendation of the PaintCare Recommendations and Interim Report[9] for creating a circular economy for leftover decorative paint in the UK is for collaboration between the paint industry, waste industry and academia. Waste paint represents a raw material resource for use in alternative applications; by working together, these sectors can identify solutions for the waste that can’t be reused or remanufactured as paint.
Alternative solutions include recycling waste waterborne paint in concrete production[13]; this has had beneficial effects on properties and economics, although the technology is at an early stage of development. Also, engineers at Rutgers, The State University of New Jersey, have developed a process to recycle waste latex paint by a process of drying the paint and melt blending with high-density polyethylene (HDPE) and polymethylmethacrylate (PMMA)[14],[15]. Mechanical properties of HDPE were unchanged; but PMMA was more flexible and tough whilst maintaining other properties. There are a few examples of recycling the more valuable and relatively easily recoverable components used in the production of paints. An experimental microwave pyrolysis process is being developed at Chalmers University of Technology, Göteborg, Sweden in collaboration with Akzo Decorative Paints UK, and Stena Metal AB Sweden to produce a pigment product composed of a mixture of the inorganic components[16]. PPG Industries Ohio, Inc. have patented a process for recovering inorganic pigment from a coating composition, involving incineration of the organic components to isolate the pigment[17].
Conclusion
Unused paint disposal represents a significant contributor to plastic waste in the UK. Much of this waste is unnecessary – it is technically feasible currently to convert around 40% of this waste back into new paint – and is largely a result of an uncoordinated approach to the collection and reprocessing of the waterborne paint that is left over from household DIY projects. In contrast to a number of countries, including Canada, the Netherlands, New Zealand and some states in Australia and the USA, there is no Extended Producer Responsibility approach for the UK paint industry. Instead, the industry-led voluntary PaintCare scheme has been initiated to promote a responsible approach to paint manufacture, use and disposal, with the aim of creating a circular economy; it will require a concerted effort to realise this aim to increase reuse and remanufacturing rates and reduce the environmental burden of the valuable raw material resource presented by waste paint.
References
[1]. https://coatings.org.uk/Statistics/Industry_Statistics_public.aspx, Industry statistics published by the British Coatings Federation.
[2]. “Irfab Global Architectural Coatings Market Study” published by PRA.
[3]. Smith, L., Bolton, P., “Household recycling in the UK”, House of Commons Library Briefing Paper Number CBP 7285, 12 September 2018.
[4]. DEFRA, UK Statistics on Waste, March 2019.
[5]. https://www.bpf.co.uk/Sustainability/Plastics_Recycling.aspx
[6]. WRAP, 2016 Plastics Market Situation Report Spring 2016
[7]. K.Y. Song, S.H. Hong, M. Jang, J-H. Kang, O.Y. Kwon, G.M. Han, W.J. Shim, “Large Accumulation of Micro-sized Synthetic Polymer Particles in the Sea Surface Microlayer”, Environmental Science and Technology, 48 (2014), 9014−9021.
[8]. “Reducing Household Contributions to Marine Plastic Pollution”; Eunomia report for Friends of the Earth (2018).
[9]. PaintCare Recommendations and interim report, prepared by the British Coatings Federation, 2015.
[10]. AkzoNobel ReColour Briefing Paper, 2015.
[11]. PaintCare local authorities survey, 2016.
[12]. BCF “A Resource Efficiency Action Plan for Decorative Paint”, 2015.
[13]. M. Nehdi, J. Sumner, “Recycling waste latex paint in concrete”, Cement and Concrete Research, 33 (2003) 857–863.
[14]. J.K. Lynch, T.J. Nosker, R. Hamill, R.L. Lehman, “Recycling of latex paint as polymer feedstock materials”, Rutgers University, Piscataway, New Jersey, 2007.
[15]. Rutgers, The State University of New Jersey, Method of recycling paints as a component of an immiscible polymer blend, WO2007087095A2, 2007.
[16]. M. Karlsson, D. Corr, C. Forsgren, B-M. Steenari, “Recovery of titanium dioxide and other pigments from waste paint by pyrolysis”, Journal of Coatings Technology and Research, 12 (2015) 1111-1122.
[17]. PPG Industries Ohio, Inc. Method of recovering inorganic pigment, WO2014150015A1, 2014.
