Civil Engineering Reference
In-Depth Information
per cent of the paint mixture. All fungicides are volatile to a certain extent and
can cause problems in the indoor climate. Many of them irritate the mucous
membranes and in some cases cause allergies.
Foam reducer
Foam reducer is often added to water-based paints so that the paint does not froth.
Drying retardants
These are added to water-based latex paints. They help reduce the evaporation
of water while painting is taking place, and usually consist of glycols and glycol
ethers. For a long period after painting is complete, glycols can be emitted and
irritate the respiratory system.
Drying agents/siccatives
These are added to various oil paints to shorten their drying time, particularly in
linseed oil paints. Normal siccatives are found in zirconium, cobalt salts and
manganese. Calcium can also be used as a siccative, preferably in combination
with other substances. Lead salts were once often used. Cobalt and manganese
form from 0.02-0.1 per cent of the dry content in the binder. Lead forms about
0.5-1.0 per cent of the dry content. The alternative is a drying oil such as wood
oil, added in the proportion of 2-10 per cent (see 'Drying oils', p. 419).
Softeners and film-forming agents
These agents are used in water-based plastic paints and consist of microscopic
plastic particles dispersed in water. When the paint dries, these particles fasten
to each other and form a film. Softeners, usually of the type dibutylphtalate, are
mostly used in PVAC paints without acrylic additives. Other types are dioctyl
phtalate and tri-n-resyl-phosphate. Softeners can release gas within a building
and can be both irritating for the mucous membranes and cause allergies.
Phthalates are known to be environmental oestregens, capable of affecting the
development of a foetus.
Perfume
Perfume is added to a few water-based paints, mostly to neutralize the unpleas-
ant smells from chemicals such as amines.
Paints with mineral binders
Mineral paints are matt and are best suited for painting on mineral surfaces,
although they can be used on unplaned timber surfaces. The most common types
