environment magazine

Innovation in Paint Technology, for a Brighter Greener Future

By Brenda Peters MICorr FTSC FIMF President of Oil and Colour Chemist’s Association

Innovation in paint technology has been driven over the past decade by the pressures of increasing cost, scarcity of raw materials and environmental concerns. The trend towards water based paints began over twenty years ago when hospital wards and sheltered housing needed to be closed for redecorating due the smell and  fumes resulting in the disruption and relocation of the occupants.  The trend was helped by the fashion for flat matt paintwork, as a truly glossy water based paint was proving very difficult to formulate.

European legislation for a reduction in VOC (Volatile Organic Compounds) levels, has also driven innovation into producing paints containing less solvent and cleaner low odour solvent.

Currently water based paint still has a small amount of solvent in it to help with film formation although some do claim to be solvent free.

But, is water based paint as environmentally friendly as people think?  Because the brushes can be washed out in water, the paint finishes up in the sewers and treatment plants where it creates problems with the bio-digestion.  Whereas with solvent based paints the brushes are cleaned with solvent.  Human nature being what it is brushes are most often left standing in solvent which evaporates into the atmosphere and the resulting brushes and congealed paint end up in landfill. The other consideration is that water based paint is made from polymers which are derived from petroleum based materials.  Solvent based paints are made from renewable plant based oils like linseed, tung oil (made from the crushed seeds of the Chinese Tung tree) and wood rosin. 

A paint has been developed in America which uses Soya bean oil and recycled plastic bottles to produce an acrylic alkyd resin which is water dispersible.  The result is a glossy paint with very low VOC levels.  The main thrust of the research was to save oil rather than to reuse recyclable material, but, the bonus is it is less polluting to the atmosphere.

There has been research into using corn starch or sugar to produce cellulose for use in paint.

The down side of using renewable plant based materials is that it takes up land which could be better used for producing food.

More exiting innovations are paints which bring additional bonuses – paints that can clean the air, coatings that can clean glass, paints that can produce electricity, paints that kill germs, paints that prevent mould growth and anti fouling paints.

It has always been known that titanium dioxide –the brilliant white pigment that goes into paint, protected the paint from UV degradation.  As far back as 1965 it was discovered that it was a photocatalyst, with the data published in 1972.  It wasn’t until 1995 when it was discovered, that when exposed to UV light it became super hydrophilic and self cleaning paint was developed. Nanoparticles of titanium dioxide are translucent so can be used as a self cleaning coating for glass, and in cosmetics as sunscreen

In its anatase form it is photovoltaic, when it is exposed to sunlight it becomes charged up and attracts particulate matter from the atmosphere, these are then washed away by the rain due to its super hydrophilicity.

When a large motorway intersection just outside Milan was painted with paint containing anatase titanium dioxide, air pollution monitors installed at the intersection showed a drop in atmospheric pollutants.  It can also be incorporated into ceramic tiles and cementitious building materials as a self cleaning agent and air pollutant remover.

Titanium isn’t the only metal with “magic properties”, nanoparticles of metallic silver incorporated into paint, produce antibacterial coatings.

Metallic copper incorporated into paint kills algae and can be used as antifouling for boats without the use of water pollutant chemicals.

The search for renewable resources to replace fossil oil derived products with plant based material does have it’s down side in that land which could be utilised for food production to feed the increasing population of the planet is being taken up to produce alternatives for oil.

Cutting atmospheric pollutants by replacing solvents with water puts extra stain on the effluent treatment plants and increases the pollution of the water courses.

Whilst innovation is always a good thing, the benefits need to be weighed against the disadvantages. Most innovation in paint technology has been driven by the need to increase manufacturing efficiency and cut costs rather than environmental concerns.  Recent legislation has forced manufacturers to decrease pollutants and formulate more environmentally friendly products.  During this process it became clear that known properties of some ingredients could be utilised for positive benefit to the environment.