Smart coats

C&I Issue 11, 2016

The Dutch multinational AkzoNobel has three major business arms – decorative paints, performance coatings and speciality chemicals. In 2008, when the company acquired ICI’s coatings activities,  it added its decorative business, which included the familiar Dulux brand, as well as gaining ICI’s packaging coatings business, which was incorporated into its performance coatings. At the time, the acquisition made AkzoNobel the largest decorative paints business in the world despite divesting its Crown paints business. Since then, there have been many mergers and acquisitions across the paints and coatings sector but AkzoNobel remains one of the major players. The market share for Dulux paints in the UK alone is a significant 40%.

The company’s portfolio includes architectural paints and coatings for the DIY and trade markets – as well as Dulux in the UK, add Cuprinol, Weathershield and Polycell, for example, with similar products in Europe and Asia. There are also marine and protective coatings for a range of substrates, coatings for packaging and even speciality finishes – AkzoNobel supplies the silver paint for the latest McLaren F1 cars. The company also boasts coatings for several major landmark buildings in the UK – including the roof over the Wimbledon Centre Court, the London Eye, the Gherkin, Wembley Stadium, Tower Bridge and the Shard.

‘Like most companies, we would say that innovation is at the heart of what we do’, says Brian Roulstone, senior R&D manager at AkzoNobel in Slough, UK. ‘We have over 4000 scientists working globally on R&D, which is targeted at reducing our carbon footprint and producing what we call “ecopremium solutions” – ie products that are better for the environment, which do not contain any chemicals of concern, require less energy downstream, and have a longer service life.’

Sustainability, he emphasises, is a central element to the company’s R&D strategy. ‘As well as servicing our customers through innovation and helping them to be profitable, we need to do it in a sustainable way.’

In 2015, AkzoNobel spent €347m on R&D, around 2.5% of its revenue. The amount invested in R&D, explains Roulstone, has remained at this level for several years. By 2020, the company expects to have reduced its carbon footprint by 20% as a direct result of its R&D strategy. R&D in decorative paints is split across two main sites – in Slough, UK, and Sassenheim in The Netherlands – and there is a smaller facility in Singapore. R&D in performance coatings is split across five sites – in Felling, UK; Sassenheim; Shanghai; Strongsville in the US; and Bangalore in India. In addition, the company has R&D labs, product development labs and customer service support worldwide.

In recent years, AkzoNobel has brought many innovative products to the decorative and performance coatings markets.

Sterishield, an antibacterial emulsion paint, was launched in 2013 to the UK trade market. The product is now used in many dozens of hospitals, clinics and schools in the UK and Ireland, including St Mary’s Hospital Paddington and throughout the new Queen Elizabeth Hospital in Glasgow, the largest hospital campus in Europe. ‘The challenge,’ explains Roulstone, ‘came down to designing an antibacterial surface that wasn’t toxic.’

Antibacterial surfaces have been around for some time but tended to use biocides, such as zinc or copper-based compounds, which are now on the REACH prohibitive lists of chemicals, he says. ‘We use benign silver particles – of a particular particle size, which are sparingly soluble – and found they are a good antibacterial agent for MRSA, E-coli and a number of other common bacterial infections.’ The silver particles interrupt the cell processes and the cells die.

Easycare is a stain-resistant emulsion paint for internal walls, which was launched in Ireland for trade professionals in 2014. Unlike most emulsions, which are hydrophilic and would therefore encourage any water-based stain to spread out, this paint has a hydrophobic surface so anything split on it will bead up and roll off. The product is now available in the UK trade sector and expected in Europe and Asia within the next few years.

Emulsion paints can contain anything up to 15 components, including polymeric binders, pigments, fillers such as calcium carbonate etc, most of which are hydrophilic. ‘The trick or skill,’ explains Roulstone, ‘involves making the surface have the properties of just one of these components, which is hydrophobic, and this comes down to the choice of the final formulation. By using high throughput experimentation and testing methods, we have been able to find and optimise the formulation that best meets our needs.’

Meanwhile, the performance coatings division has been working on amphiphilic coatings, including the launch of Intersleek 1100SR, in 2013, a biocide-free antifouling coating for the hull of ships. Intersleek 1100SR uses a slime-release technology based on fluoropolymers. The amphiphilic nature of the surface means it is both hydrophobic and hydrophilic, which discourages slime or slightly larger sea creatures or fauna from adhering to it – if any do settle on the surface, as the boat moves through the water they simply fall off.

This is good news for the shipping industry. According to the Office of Naval Research in the US, the build-up of biofouling on ships – barnacles, seaweed, slime etc – can damage hulls and propulsion systems, and lead to in an increase on the drag of the vessel by up to 60%. This, in turn, reduces the speed of the vessel by up to 10%, which can require a 40% increase in fuel consumption to compensate.

Since the average container vessel uses around 300 tonnes of fuel/day, at a cost of some $150,000, antifouling coatings represent huge savings for the industry, with the added advantage that reduced fuel consumption leads to less CO2 and SO2 emissions, and thus a better environmental footprint.

In addition, in 2015, the company launched Intertrac Vision, a free advisory service for ship owners to help them decide when and which coatings best suit their vessel requirements, depending on the waters they travel. It is a software package that makes use of digital technology and Big Data. Working in collaboration with IBM’s geospatial data scientists, and sponsored by the government’s Innovate UK, AkzoNobel is collecting huge amounts of data from satellites and marine sensors – information on the location of ships, the speed at which they are travelling and the type and condition of the waters through which the ships are travelling, including surface temperatures and oxygen content, for example, to produce a detailed model of global marine life. Algorithms can then be used to work out, for example, the amount and cost of fuel needed for any journey with and without an antifouling coating, and the knock-on environmental benefit in terms of reduced emissions, as well as when a ship’s hull and propulsion system would need to be recoated or cleaned.

If antifouling coatings are the Holy Grail of the maritime coatings business, the Holy Grail of the coatings industry generally, but especially the DIY market, is a move away from solvent-based paints to water-based ones, and ultimately to zero-solvent based products. ‘If you can remove solvents, you remove harmful VOCs and the knock-on effect is that the carbon footprint of a water-based paint is substantially lower than the carbon footprint of a solvent-based paint,’ explains Roulstone.

Many companies and researchers worldwide have been working on this problem for some years and there are several technologies under investigation and indeed being used – from traditional alkyd-based polymer systems, which are used for non-drip gloss paints, to the acrylic latex-based technologies (see C&I, 2014, 7, 24).

Roulstone believes AkzoNobel has played a big part in recent years in converting the market towards water-borne technologies in the DIY market, especially in NW Europe.

Its success in this space, he says, comes down to using smart formulations of polymer system and solvent, but acknowledges there is still more work to be done. ‘Although there are several water-based products on the DIY market,’ he said, ‘it is difficult to match the high level of performance of a solvent-based product with a water-based one. And even water-based paints need organic solvents to aid film formation during the drying process.’

That AkzoNobel won the contracts to coat some of the UK’s landmark buildings is largely down to the fact its coatings meet demanding international and architectural specifications. For some, like the Shard and Wimbledon Centre Court roof, polyester powder coatings, some of which were developed at the Felling labs, were used. They are, in the main, protective and corrosion-resistant coatings, capable of standing up to significant environmental challenges, but they also need to look good for many years – AkzoNobel guarantees these coatings against colour, gloss and appearance change for up to 40 years.

The advantages of using powder coatings on ‘factory-made’ structures are many, explains Roulstone. ‘They are solvent-free, low waste because the overspray can be collected and reused, and have fast process times. Also, unlike most spray paints, the powder particles are attracted to the substrate electrostatically, so the paint wraps around the object allowing the back to be coated while spraying form the front.’

The London Eye posed different problems, first because it was originally a temporary installation, which later became a permanent one, so any recoating needed to be done in-situ, which discounted the use of a factory-based powder coating. Secondly, the structure sits above and below the water level, which needed to be factored into any coating used.

The original coating system applied in 1999 comprised a zinc-based epoxy primer; a high solids, low VOC epoxy iron oxide coating; and an acrylic polyurethane coat. When it was repainted in 2003, several coats were again used, including a polysiloxane coat, which innovatively contains no free isocyanates, and therefore of significant environmental benefit.

For the future, AkzoNobel is putting its faith in R&D. In collaboration with researchers at the University of Sheffield, UK, for example, the company is finding out how Nature makes colour.

Already, the Sheffield researchers have discovered that the colour of bird feathers is a result of their structure and the way they interfere with light rather than the presence of any dyes or pigments.

Andrew Parnell, research fellow in soft matter and biophysics in Sheffield’s department of physics and astronomy, and his colleagues used X-ray scattering experiments to study the blue, black and white feathers of a Jay.

The feathers are made of a nanostructured spongy keratin protein, and the researchers found that the characteristic blue white and black colours are determined by the size of the holes in this structure (Nature Scientific Reports, doi:10.1038/srep18317) – large holes give a broader wavelength of reflected light and the colour white; smaller holes result in the colour blue.

These findings have huge implications for the paints and coatings industry, says Roulstone. ‘If we could make colour without synthetics pigments it would be very beneficial for a number of reasons not least of which would be an even lower carbon footprint for the industry since many of the current pigments are carbon and energy intensive to make.’

AkzoNobel is also investing €5m in a partnership with the University of Manchester, UK, to study corrosion protection. The Corrosion Protection Partnership (CPP) started in 2013 for five years, with the possibility to extend it for an additional five years from 2018.

There are over 30 projects currently being funded by the CPP – both fundamental mechanistic studies and applications-led studies, such as how changes in the polymer composition and the curing process determine the properties, which enhance corrosion protections, and the potential use of graphene as a protective coating.

The paints and coatings industry is certainly a lot smarter and sustainable than it was even just 10 years ago.

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