Poly-wood
110705.01
9
1
Characteristics of Poly-wood
1.1 Resistance to chemicals and other media
Due to it’s non-polar structure the paroffin hydrocarbons, Poly-wood
has an exceptionally high molecular mass. This makes it highly resist-
ant to chemicals and other media. It is resistant to aqueous solutions
of salt, acids and alkalis.
Poly-wood has a tendency to stress-cracking, especially due to inter-
nal mechanical strains. It is important for designers to use Poly-wood
in low stress applications.
High temperature can affect chemical resistance to a marked degree,
depending on the surrounding medium. Account must therefore be
taken of this in designing installations for the chemical industry.
Poly-wood is resistant to many solvents up to 60°C, but is however
penetrated by aromatic and halogenised hydrocarbons and certain
oils, greases and waxes. This penetration is only very slight up to 30°C.
Poly-wood has little or no resistanco to strong oxidants such as nitric
(V) acid, ozone, fuming sulphuric acid, hydrogen peroxide or halogens!
1.2 Resistance to water vapour and gases
Poly-wood is water-repellent. It does not swell when stored in water.
There is a certain permeability to gases: for water vapour this is very
slight, but very high for O
2
and CO
2
as well as many odorous substances.
1.3 Weathering resistance
Poly-wood is resistent to the elements, including UV light (UV stabi-
lisers are added to Poly-wood).
However, Poly-wood exposed to sunlight in the open air for Iong pe-
riods can be affected, especially by the UV element in sunlight and
acid in the atmosphere. These factors start physical-chemical pro-
cesses with the following consequences:
- discoloration (often yellowish)
- embrittlement (loss of toughness)
- loss of mechanical properties.
1.4 Fire behaviour
Combustibility is often a technical problem with plastics and an ob-
stacle to their use. Various test methods are used to classify combusti-
bility. DIN 4102 subdivides materiels into combustible and non-com-
bustible. Poly-wood is a normally combustible plastic. DIN 4102
places all combustible materials in Class B, subdivided as follows:
B1 - slightly inflammable
B2 - normally inflammable
B3 - highly inflammable
Oxygen content is another guide to inflammability. This test as per
ASTM 2863 shows how much oxygen a plastic requires to catch fire
and continue to burn. The number gives the oxygen concentration
(vol. %) in a nitrogen/oxygen mix necessary to maintain combustion.
Poly-wood fire behaviour:
Behaviour in fire
DIN 4102 B2
UL94 HB
Oxygen index
18
External ignition
350
Self ignition
445
1.5 Electrical properties
Poly-wood is usually a good electrical insulator. This property is put
to specific use in many applications, however, there are many known
applications which require electrical conductivity or anti-static be-
haviour. Electrical charges on the surface of normal plastics can pro-
duce a potential of several kiloVolts and sparking can couse dust ex-
plosions. Gas-air mixes, and to a lesser extent dust-air mixes, quickly
reach minimum ignition energies.
Many modern electronic components can be damaged by elec-
trostatit charge. For example, conveyor belts for such components
should not be insulated, they must be able to conduct electric en-
ergy away.
1.6 Suitability for use with foodstuffs
The German Health Office (BGVV) in its Recommendation III on PE ad-
vises use of PE to manufacture consumer goods under the meaning of
Section 5 Part 1 No. 1 of the Food and Consumer Goods Law (LMBG).
Poly-wood does comply with this recommendation.
With regard to the colouring used, German Health Office Recom-
mendation IX ‘Colouring agents for Colouring Plastics’ should also
be consulted.
Materials which are safe in contact with foods can also be used in
contact with drinking water. The ‘KTW’ recommendation on plastics
and drinking water should be consulted in any decision.
1.7 Expansion and contraction
Poly-wood differ from wood because it react more to temperature
change. Poly-wood contracts and expands at the rate of 2.10
-4
m/m/°C.
This interprets into changing approximately 3 mm in size for every lin-
ear meter of length or width over a 15°C temperature range.
Drilling oversized holes for screws or fasteners prevents problems. If
oversized holes are not used, Poly-wood installed in low temperatu-
re may bow when it warms. Poly-wood installed at warm temperatu-
res may crack when cooled and fasteners may bend or sheer.
1.8 Structural capabilities
Poly-wood is not a structural material. When using Poly-wood, it
must be supported by a load bearing framework or rigid shell such
as a fiberglass hull.
Poly-wood is a plastic, and like all plastics, it will cold flow (change
shape as a result of gravity, over time).
Using Poly-wood means less waste because there is no grain like
wood. Parts can be cut from any part of the sheet, in any position,
getting the most out of every sheet.
1.9 Finishing
Poly-wood textured finish (on both sides) resists scuffing and
scratching.
1.9.1 Protecting the finish
Poly-wood is shipped with a protective masking on one side to pro-
tect its finish during shipping, cutting and machining. It is sug gested
that it remain on the product for as long as possible during fabrica-
tion. To further protect your sheets we encourage you to mask the
other side when you receive them.
ENGLISH
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