Sustainable coatings

Paint the world green with sustainable coatings

There is now a widespread desire among consumers and manufacturers to improve the sustainability and environmental impact of the coatings industry. This shared intent has led to the rise of sustainable coatings – products developed with a focus on reducing or eliminating harmful components or processes or making the substrate to which they are applied more sustainable. In the UK alone, one million litres of decorative paint are thrown out every week. Some of the ways in which companies are decreasing their environmental footprint are through the reduction of VOC compounds and emissions, the expansion of water-based formulations in their portfolios, increasing recycling capabilities, and creating coatings that are efficiency- and durability-boosting.

In this article we look at the problems plaguing the sustainability of coatings, the variety of ways that coatings are being made more sustainable, and how companies are making the industry greener.

Sustainable coatings through durability and innovation

There are three critical aspects of paint which affect sustainability: durability, quantity used, and formulation. The longer a paint lasts without the need for recoating, the less paint needed for optimum coverage and opacity, and the use of sustainable component ingredients all add up to a more environmentally-friendly, greener product. By focusing on improving the durability of their coatings and the sustainability of the processes involved in their production, paint and coatings companies are reducing fuel usage, CO2 emissions, VOC emissions, production wastes, and overall power use.

Providing a long-lasting coating for the Forth Bridge is an example of how to make sustainable coatings.

The Forth Bridge uses protective coatings to enhance its durability.

1. Durability – less paint, less often means increased sustainability

The ability to provide a flawless finish with optimal performance attributes while expending the least amount of resources is one of the goals of the coating industry. Coatings with better coverage and opacity require fewer coats, decreasing the overall environmental impact. Increasing the lifespan of a coating is another way in which companies are improving sustainability – creating formulations that last longer without chalking, fading, yellowing, peeling or otherwise failing and requiring an early recoat.

Durability does not just apply to the effects of weather and time; increasing the abrasion resistance and general wear-ability of the coating will also lengthen its life. The Forth Bridge in Scotland now has its one-and-a-half mile length protected by a specially contracted protective coating from Sherwin-Williams – good for 25 years, no longer the never-ending coating job.

2. Coatings to make substrates sustainable

Coatings may protect and beautify, but they also enhance the function of a substrate – often with positive results for the environment. Antifouling coatings are one such product. The buildup of sea life on the hulls of the world shipping fleet increases fuel usage by 40%, producing the equivalent of 70-80 million tonnes of greenhouse gases. By applying antifouling paint, biofouling is reduced or eliminated and the performance and sustainability of the world shipping fleet is dramatically improved.

This same principle applies to lightweight aerospace coatings for planes, as well as coatings for vehicles. By protecting substrates ranging from buildings and infrastructure to machinery, coatings increase the lifespan and sustainability of these valuable resources. Sustainable coatings are more than just those which use sustainable ingredients.

VOCs and heavy metals – bad for health and the environment

Two of the biggest offenders when it comes to harmful substances in coatings are heavy metals and VOCs. A heavy metal is a dense metal or metalloid which are potentially toxic. VOCs (Volatile Organic Compounds) are organic chemicals with a very low boiling point, some are natural and some are man-made. The low boiling point means that they evaporate easily into the surrounding air, emitting gasses long after the paint has dried (causing that ‘paint smell’).

  • VOC EMISSIONS – In paint, the solvent usually has the highest concentration of VOCs because they need to evaporate for the paint to dry. A few of the VOCs found in paint include formaldehyde, benzene, ammonia, xylene, and toluene. Some VOCs react with oxides of nitrogen to form ozone, which is a precursor to the formation of smog. In fact, VOCs are a significant contributing factor in the creation of air pollution in urban areas. Inside buildings VOCs can contribute to ‘sick building syndrome’ as well as causing health problems and allergies.
  • TOXIC HEAVY METALS – Lead is the most famous of the heavy metals used in paint. Once used extensively as a white pigment, it has been banned for use in all paint (though not all industrial coatings) in the UK since 1992 due to its toxicity. Other heavy metals are still present in paint, however, including cadmium and chromium. Heavy metals are a particular concern in automotive coating, but they are also present in other paint types as they speed the drying process.

Water-based paint: solving the VOC problem

VOC regulations and consumer demands have led to a market dominated by the desire for greener coating solutions. When VOC regulations first eliminated the VOC-heavy, solvent-based paints, consumers turned to water-based sustainable coatings as an alternative. Water-based coatings are naturally low in VOCs as they use water instead of a chemical solvent.

As technologies have improved and companies have invested in their low-VOC coatings, the market has only continued to grow. Today, 80-90% of the residential/architectural paints sold in the UK are water-based. They can be used for substrates from metal to concrete and wood, and technologies include polyurethane, epoxy, acrylic, and more.

Paint recycling: A sustainable solution with the BCF

Recycling paint will help the industry reach its sustainable coatings goals.

Recycling paint can reduce the 55 million litres of paint thrown away each year.

Every year, 13% of all paint sold in the UK is thrown away to be burnt or buried in landfills. This adds up to one million litres of paint a week, enough to fill 20 Olympic-sized swimming pools. The majority of this waste comes from the DIY renovator/redecorator guessing their required paint quantities incorrectly. Dulux, Crown Paints, Sherwin-Williams, B+Q, and more offer online paint calculators to take out some of the guesswork, and yet the waste continues. Leftover paint is mostly still useable, and storing it in the garden shed to inevitably deteriorate while waiting for ‘one day’ is simply a waste.

The British Coatings Federation (BCF) wants to change the way we deal with leftover paint through the PaintCare scheme. Led by the BCF, PaintCare brings together local and national government, the waste industry, paint companies, retailers and other stakeholders to help solve the problem of leftover decorative paint. Partners of the scheme include AkzoNobel (Dulux), PPG, Sherwin-Williams, Valspar, HMG Paints, Crown Paints, Watco, and more. Further initiatives like Community RePaint recycle paints by redistributing them among individuals, families, communities and charities. The aim is to change the way the UK deals with leftover paint and to provide the recycling services needed to break the cycle of waste.