Coatings - Architectural & Protective

Nothing brightens up a space like a fresh coat of paint. All too often, however, the "clean" smell of new paint is actually vapour released from the toxic ingredients used as solvents in conventional paints. Known as volatile organic compounds (VOCs), these include benzene, formaldehyde, kerosene, ammonia, toluene, and xylene, all of which are known carcinogens and neurotoxins.

About 50% of paint manufactured in Australia is for the purpose of architectural coatings. The Australian paint sector comprises of some 30 manufacturers representing over 96% of the paint products $2B industry. Architectural paint products are changing to provide more specific formulas for special needs while seeking to improve performance against the most common demands of wear, sunlight, long lasting colour and suitability for new and varied surfaces. Many paint producers are also increasing environmental performance in response to international and regulatory trends and consumer environmental preference.

Up to 30 separate ingredients or raw materials, some solid, some liquid may be combined to make paint. Each of these ingredients needs to exist as a sooth, homogeneous and stable mixture in the end product.

The Constituents of architectural paints are summarised below:

• Pigment is normally an insoluble fine particle solid material. The pigment primarily gives the paint its colour and covering power. Pigments affect the flow, gloss, durability, corrosion resistance, fire resistance, antifouling and other qualities of the paint.
• The binder (or "vehicle") is the matrix that carries all the ingredients in an even, homogeneous manner throughout the sample and binds it all together. The binder gives the dry paint film properties such as gloss, adhesion, hardness, toughness, flexibility, durability and speed of drying.

Additives are materials added to the paint to assist specific properties such as drying, flow, brushability, colour uniformity, to stop skinning in the can, to name just a few. The solvent is the material mixed with the binder and other ingredients to give the paint the right consistency to for application. The solvent in 'solvent-based' paints is petroleum based and the solvent in water-based paints is mostly water. In some cases water based paints (also known as latex or PVA or acrylics) are slowly replacing solvent based paints as new technology ensures equivalent performance properties. Water-based paints require co-solvents like ethylene or propylene glycol, or a glycol ether substitute to work properly. Glycol ethers are known as teratogens (cause birth defects) and are banned from use in many countries but are still used in many paints in Australia

The more VOCs the paint contains, the stronger the odour. Exposure to VOCs can worsen asthma symptoms and cause nose, skin, and eye irritation; headaches, nausea, convulsions, and dizziness; respiratory problems; nerve damage; and, in some cases, liver and kidney disease.

The VOCs emitted by paint solvents also contribute to indoor air pollution and the formation of ground level ozone. A study conducted by the U.S. Environmental Protection Agency showed that VOC levels indoors can be 1,000 times higher than outdoor levels when an indoor paint is drying. Another study found that the application and drying of paint releases VOCs at a higher rate than any other product used indoors. In sunlight, some organic solvents used in paint react with nitrous oxides in the atmosphere to form smog.

Consumer Behaviour Tips

The environmental benefits of choosing an environmentally preferable paint can be offset by improper use during application and disposal. Below are a range of consumer tips to minimize environmental impact in the process of removing, applying and disposing of paint;

• As a general rule durability will outweigh other environmental characteristics since it reduces the number of times a surface will need to be painted;
• Calculate the area that needs to be covered and buy only enough paint to cover that area. The best way to avoid problems of disposal is to use all of the paint;
• Give leftover paint to someone who can use it;
• Take into consideration when buying paint that oil-based paints require additional solvents when cleaning;
• Paints with low VOCs allow access to freshly painted areas sooner or without need for people to leave a site during the painting process;
• Never pour paint down the drain. Where waterbased paints cannot be recycled or reused they can be poured out onto paper or left in the can to dry before disposing;
• Where oil-based paints cannot be recycled or otherwise put to use they should be disposed of as hazardous waste or left to completely dry before disposing;
• Light coloured surfaces reduce lighting costs;
• Use vacuum sanders to avoid hazardous dust from entering lungs and the broader environment;
• Close all containers after use to avoid emission of volatile content.

The Australian Paints Approval Scheme can supply free brochures on safe disposal of residual paint. Further reading and resources and the environmental loads of paints: