No. 1031 - Miljøstyrelsen

• Defoamers, flow control agents and levelling agents in water-based paints.
Silicones are used as water repellents on mineral-based products like masonry,
concrete and tiles for both interior and outdoor applications. The silicones can
be applied as neat materials, in solvents or as water-based emulsions. Other
silanes are used for this application area as well.
Siloxanes resins are used in high-performance paints to modify paints based
on polyester, alkyd, epoxy and acrylic e.g. for anticorrosion. Silicones are used
in high-temperature resistant coatings for exhaust pipes and stoves, household
appliances and industrial applications.
A growing application area of silicones is antifouling paints used as alternative
to TBT-containing paints. The silicone coating form a surface to which it is
difficult for the fouling organisms to adhere.
Silicone liquids are widely used at low concentration in water-based paints in
which the siloxanes improve the flow properties of the coating, eliminating
wetting problems and thinning the coating edge.
Besides, silicones are used in small volumes in inks and dyes.
Consumption
Based on Will et al. 2003, the total consumption of silicone fluids for paint,
coating and waxes can be estimated at 130 t/year. The consumption is growing
by about 1.5% annually in W. Europe. Besides, water repellant coating
and paints account for the major part of the consumption of silicone resins
which can be estimated at 210 t/year. Roughly estimated some 300 t in total
may be used for paints, inks and coatings. This figure represents the amount
of siloxanes in products used in Denmark. The use of siloxanes for production
of paints in Denmark has not been investigated.
According to the Product Register the total volume of siloxanes in imported
products (46 product types) was 40-78 in 12,000-21,000 t of products. The
total volume in produced and exported products was 7-426 t and 5-244 t respectively.
Most of the products are registered as paint and lacquer without
further specifications. As many water-based paints are not registered, the total
volume in paints may be significantly higher.
The data from the Product Register demonstrates that the siloxanes are used
in low concentration in a very large volume of products.
Siloxanes used
Paints and coatings are the main application areas for silicone resins. According
to the Product Register retrieval some of the main substances used for this
field are polydimethyl siloxanes with silsesquioxanes (siloxanes with a Si/O
ratio of 1.5) which form highly branched polymers.
Besides the compounds with silsesquioxanes, polydimethyl siloxanes are registered
as the most used siloxanes for this application area.
Silicones with side groups containing among others polyethylene and polypropylene
glycol butyl ethers are used at low concentrations (