Handbook of Solvents - George Wypych - ChemTech - Ventech!

18.3 Indoor air pollution by solvents 1239
Product groups Compounds Application
Silicone resin
products, water
dilutable (M-SF01)
emulsions of silicone resins mineral fillers, inorganic/organic
pigments, water (dispersing agent), additives
(film forming agents < 3%)
Solvent composition is an important aspect in classifying paints and varnishes. 5 Main
groups are:
• Solvent products. These products contain solvents of various mixtures, types and
concentrations depending on the properties desired (e.g., application method,
surface film or skin formation, see above 18.3.1, 18.3.2.1, Table 18.3.1 and 18.3.2).
Solvents are normally the main components of these products (for example up to 80
% in nitrocellulose varnishes, low solids).
• Solvent reduced products. These contain solvents in lower concentrations compared
to conventional products and hence have a higher content of solids. 1,2 The main
groups of solvent reduced paints are medium solid contents (solids 55-65 %) and
high solid contents (solids 60-80 %).
• Waterborne coatings. This group contains deionized water as a dispersing agent.
Normally cosolvents are added (up to 25 %). The term “waterborne coatings” is
mainly applied to industrial coating materials, which differ from silicate colors,
wood preservative varnishes and emulsion paints.
• Solvent-free products. The products of this group are produced and applied without
organic solvents: powder coatings, radiation curing systems, solvent-free water
coating (without cosolvents).
The use of paints and varnishes containing high solvent concentrations is becoming
less common, solvent-reduced products, waterborne coatings and solvent-free products are
applied more often.
Whereas environmental and health-related concerns call for the reduction of solvents
in paints and varnish products (see 18.3.3.2 and 18.3.4), qualitative aspects still demand the
use of solvents in some fields of application. 12 Solvent-reduced products should achieve the
same qualitative properties as solvent-containing products (e.g., application properties, periods
of guarantee, limited costs, loading capacities, surface properties). The development
of solvent-reduced or solvent-free varnish products with high quality (e.g., durable, good
application properties) and limited costs must be encouraged if not mandated. In some
fields of application (e.g., waterborne coatings, high solids in varnish coatings of vehicles) a
lot of developmental work has already been done. Additionally, other components in varnishes
apart from solvents or modifications of application techniques can improve the properties
of solvent-reduced paint and varnish products. Nevertheless, a wide rage of quality
exists in paints and varnish products which are offered commercially and, in some cases
(e.g., concerning film forming processes, processibility, corrosion protection, purification,
special applications or wood preservation), solvent-based products are still preferred. In the
field of wood preservation especially, solvent-based products (alkyd resins) are used because
of some technical advantages (e.g., more solid surfaces) but alternative high solid systems
are available. 12