1. Resin
2. Crosslinking agents
3. Pigments
4. Solvents
5. Extenders
6. Additives
A powder coating is produced without solvents, and all the components have to
be on non-volatile basis. That means a difference in available components for
production of a powder coating and a wet lacquer. In the presentation of the
lacquer components powder coating composition will be emphasised because
The resin is the most important component in a lacquer, and the part which gives the
name of the lacquer (e.g. epoxy lacquer). The dry lacquer coating consists of
resin, plus pigments, and additives, which are dispersed in the resin. The resin
should give good adhesion to the surface of the substrate. Wear and weathering
resistance, chemical resistance, ductility, gloss, and hardness are factors
dependent on the type of resin.
Crosslinking agents or hardeners are needed to get curing of some types of lacquers. If no crosslinking agent
is used, only physical drying of the lacquer coating will occur. No crosslinking
will take place, and mechanical properties and chemical resistance will be
very poor. Polyamide is an example of a crosslinking agent, which is used in a
epoxy resin.
Pigments are mainly added to give the right colour and covering power. They can also
influence other properties like hardness, chemical resistance, protection against
UV-radiation, or
There are a wide range of both organic and inorganic pigments, even if not all
of them are suitable for powder coatings.
The major types of pigments being used in powder coating products are:
- inorganic pigments
- organic pigments
- carbon black
- titanium dioxide
Solvents are used to give the lacquer the right consistency for the different
application methods. During the application and drying the solvents evaporate. Some
lacquers can be applied without solvents or with very small amounts of solvents.
The most well- known type is called powder lacquers. A powder lacquer is made by
mixing dry components together, melting to a homogeneous mass,
cooling/solidification and milling of the lacquer chips to the right powder size.
Extenders are chemically inert, natural or artificially manufactured inorganic
compounds, which do not have any colouring and hiding properties.
Extenders are mainly used to reduce the price of the final lacquer coating,
but they also bring the following positive effects:
- reduction of coating sagging by giving "body" to the lacquer
- coating reinforcement against abrasion or wear
- reduction of degrading effect of UV-light
- improvement of corrosion resistance
- improvement of moisture resistance
Barium sulphate, calcium carbonate and aluminium silicates are the three main
extenders which are used in powder coatings. China clay, French chalk or
similar inert white pigments are used in liquid lacquers.
Additives are used in liquid and powder lacquers to produce special finishes or to
ameliorate their properties.
The seven main types of employed additives for powder lacquers are:
- accelerators
- gloss agents
- dry flow agents
- flow agents
- matting agents
- texturing agents
- wax
Components in a lacquer (Topic: 14020)