Technical information

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Properties of materials
Plastic
Plastic is a modern material that
is being constantly developed
oering a range of benefits. The
scope for designing with this
material is improving, sev-
eral functions can be used for
integration and the designs can
also be made lighter compared
with metal designs. Production
eciency is good, since plastic
parts rarely require additional shaping. Right from the start, the
part has the correct surface structure and colour without the need-
ing to be cleaned or trimmed.
From an environmental stance, plastic uses significantly less
energy in the production of plastic parts compared to metal parts.
The total amount of oil used in the manufacture of plastic parts is
significantly smaller, too. Additionally plastic can be reused, either
recycled as new products or used for energy.
A number of Fagerhult’s markets place particular re classica-
tion requirements on products inclusive of plastic. This may require
the use of ame-retardant plastics in our parts to reduce the risk of
fire starting or spreading via our luminaires. Fagerhult abides by the
RoHS Directive, which prohibits the use of mercury, cadmium, lead,
hexavalent chrome and the flame-retarding agents PBB and PBDE.
A good choice of materials and good design solutions can avoid the
need for flame-retardant agents (including the less harmful ones).
As stated above, there are many advantages to using plastic, but
at the same time it places great demands on design and choice of
materials. Depending on the area of application for the product
and other specifications, tests and simulations must be constantly
carried out during the development phase to ensure that all require-
ments are met without jeopardising safety and quality.
There is a whole host of dierent plastics available on the market.
Each has been produced to meet the demands made of the prod-
ucts. A selection of plastics is given below.
PVC (polyvinyl chloride)
PVC is a polymer that consists of several vinyl chloride molecules
bonded together. It is a thermoplastic produced by adding chlorine
to ethylene and is often used in the construction industry, for pipes,
plastic mats and insulation of cables/wires, for example. A mate-
rial consisting solely of polyvinyl chloride is quite sti, and for this
reason softeners (phthalates) are generally added to make it easier
to handle and more durable. The material has good chemical and
weather resistance properties.
When PVC burns, hydrochloric acid and chlorinated hydrocarbons
are formed because of the plastic’s chlorine content. The smoke pro-
duced when burning is aggressive, attacking metals and electronic
equipment in the building. The associated cleanup cost following
such a fire causes many customers to prefer other alternatives
instead.
The softeners are constantly given o and can migrate to and attack
other plastic materials. They are also considered to be damaging
to the environment and injurious to health and they can adversely
aect reproduction.
Fagerhult products are connected internally using PVC-free wires
and the mains cable can also be supplied to special order in a PVC-
free design. Otherwise, PVC is not a material that is found in our
products.
PC (polycarbonate)
Polycarbonate is both a transparent and a coloured thermoplas-
tic with very high strength, including at low temperatures. It is
often used in applications that require resistance to knocks, blows
and kicks, including visors, machinery protection, CDs and other
products that need to be durable and/or transparent. The material
is self-extinguishing. When designing, it must be ensured that the
material is not exposed to continuous tension as this will ultimately
lead to cracks forming.
Polycarbonate can be cold bended (roughly like sheet metal),
extruded lengthways or injection moulded. In lighting, it is used to
insulate lamp holders and bodies as well as for shades, reflectors
and dust protection. PC is often the material of choice for plastic
luminaires sold as vandal proof.
Polycarbonate is sensitive to rippling and has limited resistance to
UV light, which turns the material yellow. For this reason, where ap-
plicable UV stabilisers are added, or the surface is coated with a UV
block (for example, the glass for car headlights). It is also sensitive to
chemical attack, especially by bases, oxidising acids, methanol, aro-
matic chlorinated hydrocarbons and ammonium. A mild soap solu-
tion should be used for the maintenance/cleaning of shades, plastic
end pieces and dust protectors. PC is also suitable for metallising.
PBT (polybutylene terephthalate)
PBT is a rigid material with good durability and chemical resistance.
It also has good electrical properties, making PBT suitable for use as
a lamp holder or body, etc. It can be used at higher temperatures,
and fibreglass reinforced PBT provides even better heat resistance.
PBT has good UV and weather resistance and also good sliding prop-
erties, which means it is often found in cars. The material is suitable
for metallising. The above properties mean that PBT is suitable for
products such as downlights, where high temperatures occur and
there is a need for metallised reflective surfaces.
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