Hunt the Hotspots in Decorative Paints: How About Titanium Dioxide?

The world is getting increasingly interested in determining the most sustainable ways of meeting society’s requirements for materials, products and services. Some governments are getting very active in this quest and so are consumer-driven organisations that have increasing concerns about the current ways we are all living.

One such organisation is The Sustainability Consortium (TSC), which was launched by Walmart initially in the United States to reflect the increasing pressures being felt by multiple stakeholders to reduce the environmental and social impacts associated with global consumption. With a membership of around 100 organisations comprising large multinational corporations together with government and non-government organisations, TSC has developed a well-financed programme of product environmental study based on in-house analytical methodology. Once the analysis is completed, the TSC informs key decision makers on product sustainability throughout the entire life cycle, which no doubt provides a significant incentive for change upstream of the retail sector.

A prime activity of the TSC is the hunt for hot spots, and one of the current areas of focus is the decorative paints industry. The TSC has already taken information and evidence from the American Coatings Association and other sources, and is expected to publish its conclusions sometime soon.

With decorative coatings so visible these days, it is tempting to wonder what sustainability hot spots will be identified. One obvious candidate must be titanium dioxide (Ti0₂). The extraction, purification and finishing processes in the manufacture of Ti0₂ pigments demand substantial quantities of energy. With an average carbon footprint of 5.2 tons of carbon dioxide for every ton of Ti0₂ produced and representing 60% of the cradle to gate carbon footprint in typical semigloss waterborne paint, it has to be a major hot spot candidate. Right?

 I shared this idea in a talk at the recent CTT conference in Chicago, run by PCI magazine and the Chicago Society of Coatings Technology, and was rightly challenged by a representative from Cristal who reminded me of the pros as well as the cons of Ti0₂.

I heard recently that for every ton of carbon dioxide BASF emits in its entire manufacturing processes, its products save the consumer three tons of C0₂ in the way its products are utilised. A parallel argument can be presented for Ti0₂ but requires a very careful analysis that the TSC studies will hopefully have the time and the patience to pursue.

While Ti0₂ has a high carbon footprint per ton, it does prove to be an essential material in many decorative paints. It has excellent properties in terms of opacity, which will significantly enhance how much paint it takes to coat a surface. The greater the opacity, the less is required to cover a given area. It may even lead to a reduced number of individual coats of paint to give an acceptable finish. Ti0₂enhances life expectancy and scrub resistance (for interiors). Itis also a highly efficient reflector of infrared radiation from sun and heat. For example, using white roofs and exteriors, Ti0₂ can reduce air-conditioning needs. Put another way, Ti0₂ is one of the key ingredients in decorative paints that enhances the functionality of coatings.

All these properties give positive sustainability benefits downstream of coating manufacture. So, maybe carbon content per ton is not the best measure that accurately reflects the overall environmental impact of Ti0₂?

We need to take account of both the pros and the cons in sustainability measurement. As Mike Binns of Cristal wrote in a presentation he gave at the European Coatings Conference in Nuremburg, Germany earlier this year, “Coatings manufacturers should carefully consider the validity of carbon footprint reduction goals based on simple ‘total’ or ‘per litre’ metrics. Pressure around such metrics with limited performance safeguards can lead to a reduction in product quality with an overall negative impact on sustainability.”

What we do need is carefully developed sustainability performance measures that reflect the overall performance of a product or a material from cradle to grave and lead to consumption patterns that best serve society’s environmental and economic needs. These measures will be very much dependent on the application the coatings are used for.

Hopefully, the TSC projects will draw on the increasing amount of work that is taking place to develop robust rules known as Product Category Rules (PCRs), which allow for declarations about the environmental properties of materials and products to be derived, verified and presented in a harmonized way. The European standard, EN 15804, spells this out for all products, services and processes used in the construction industry. That’s quite a feat! I have no doubt that we will be hearing a lot more about industry standards and PCRs in the future.

 Identifying ‘hot spots’ may not be as simple as one first thought. One thing is for sure, decorative coatings are very much in the public eye!