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Paints PDF Print E-mail

Paints consist of three main components: pigments and fillers give the paint colour and body; resins bind the pigments and form a film; solvents or water keep the paint liquid until it is applied. For buildings and furniture their main purpose is to coat the surface to protect it from sun, rain and humidity (e.g. cars, walls) and from physical damage (e.g. floors). Paints differ from wood preservatives in that they are only a surface treatment, and from polishes, which offer some protection but are mainly for aesthetics. For floor treatments they are often called 'sealants'.
There are many different types of paints, for example oil, alkyd, epoxy, vinyl, acrylic (see Glossary), polyurethane, chlorinated rubber, polyvinyl acetate, varnishes. They vary in the way they dry. Oil and alkyd-based paints dry by reacting with oxygen in the air. Acrylic paints, including some floor waxes, and vinyl acetate paints contain a few per cent of high-boiling solvents and are applied as an emulsion in water. When the water evaporates, the emulsion breaks and they form a film which slowly loses the solvent. Acrylic paints can also be applied as a solution in volatile solvents, as in car body paint. Epoxy and polyurethane paints set when two components are mixed; some other polyurethane paints absorb moisture from the air in the setting process. Chlorinated rubber paint and cellulose lacquer dry once the solvent has evaporated.

Good ventilation and respiratory protection are essential when using all paints and protective clothing to cover the skin should be worn when using volatile products.
     The most common household paints are either water emulsions or are mineral turps based. Acrylic paints offer lower health risks than mineral turps based paints, but should still be used with caution. Reports have shown that extended exposure of men to the solvent used in water-based paint can lead to a two to threefold increase of the probability that a child fathered by them is miscarried. Occupational exposure of painters is recognised by the IARC as a category one cancer risk. Good ventilation of rooms for a few days after painting is therefore important.
     Polyurethane floor coatings may release volatile ingredients for some time after application and drying. When they are first applied they emit tolulene isocyanides, ketones and aromatic solvents and very good ventilation during use is essential. They may be hazardous for people with chemical sensitivities and respiratory problems such as asthma. Avoid exposing small children to a newly coated area as they are more susceptible to chemical impacts.
     Antifouling marine paints contain highly toxic material and have to be handled with care (see Antifouling paints).
     Some lacquers contain lead acetate which can be absorbed through the skin and is a suspected carcinogen.
     Industrial paints usually contain volatile solvents, some of which are harmful. They can affect the respiratory tract (see Paint thinners) and the fatty membranes around the nerves and the brain. Prolonged exposure can lead to nerve damage and to loss of memory. These solvents are also highly flammable and there is danger of fire and explosions when they are used. Good ventilation is therefore essential for health and safety, and use a respirator if you can (see Protective clothing).
     Houses built before 1970 may have been painted with oil paint based on white lead, and care must be taken when sanding or scraping such paint not to breathe the fumes or dust; burning it off should be avoided (see Lead, Paint strippers).
     Epoxy paints are used in swimming pools and to make industrial equipment water, acid and solvent proof. They may contain residual amounts of toxic amines before they are cured and must be handled with care. No free amines remain after curing and the paints are safe even for the food industry once they have been washed with detergent. See Epoxy resins.

Environmental effects
The solvent vapours that escape from paint that contains VOC's are a major source of air pollution and greatly contribute to the formation of smog, which is caused by the action of sunlight on the many different air pollutants.

Use non and low-VOC plants, a number of large paint manufacturers produce low-VOC paints. Try and use plant-based or water-based paints wherever possible, but remember that even if something is natural it may produce toxic fumes. If you have any concerns then obtain the material safety data sheet from the manufacturer.

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