Scania Identification of materials Service Manual
Identification of materials
Parts made of thermoplastic
Parts made of thermosets
Plastics
Plastics are divided into 2 main groups; meltable (thermoplastics) and non-meltable
(thermosets).
Thermoplastics are cast or injection moulded and unlike thermosets they lack bonds
between the plastic molecules. Thermoplastics can be recycled with good results.
Thermoplastic recycling is a good way to conserve base materials and save money.
There are different types of thermoplastics and it is important to keep them separate
during recycling work so that the mechanical properties of the recycled material are
not impaired. Certain material combinations can be compensated using additives that
make the plastics miscible. Mixing in new base material can also improve the properties.
Plastics
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313 257
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Scania CV AB 2012, Sweden
Identification of materials
Examples of plastics that are not suitable for mixing are listed in the table below:
Base material
ABS PA PBT PC PC+ABS PC+PBT PE PMMA PP PVC
ABSABAAAACACA
PABABCCCBBBC
PBTABAAAABBBC
PCACAAAABABC
PC+ABSABAAAABABC
PC+PBTACAAAABABC
PECBCBCCACAB
PMMAABBAAABABB
PPCBCCCCBABA
PVCACCCCCBABA
Mixing material
A = Compatible
B = Compatible in pure mixtures (<5%)
C = Incompatible
Plastics
Painting thermoplastics is disadvantageous with respect to recycling even though
there are methods of separating the paint. Plastics age and become brittle. Take a random sample for measuring the melting index to see how far degradation has advanced. See ISO 1133.
Pure plastic that does not contain a high degree of other material (maximum 5% of
another plastic), and has not degraded due to long periods of damp or heat treatment
can be classified as new plastic, though with reduced properties.
Mixed material or material with molecules degraded to short chains can only be reshaped to very simple products or used for energy recovery.
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Scania CV AB 2012, Sweden
Identification of materials
Thermosets are plastic prepared with hardeners which bind the plastic molecules to
each other. Thermosets are strong and rigid but brittle. Therefore it is often reinforced
with for example glass fibre mat.
Thermosetting plastics are more difficult to recycle as it is not possible to melt and
reshape them. The methods of recycling available today are energy recovery and, to
a certain degree, pulverisation for filling.
Plastics
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Scania CV AB 2012, Sweden
Identification of materials
Marking of plastics
Scania marks all its plastics (where there is space for a mark) in compliance with
Scania Standard STD 387, which in turn is based on ISO 11469 - Generic identification and marking of plastic products.
The marks consists of international designations according to the following standards:
ISO 1043 Plastics - Symbols and abbreviations
ISO 1433 Vulcanised rubber - Choice of required properties
ISO 1629 Rubber and latex - Terminology
The marks start and finish with the arrow symbols > and <.
A short description of the most common thermoplastics used by Scania follows below. Plastics are designated by 2 to 4 capital letters (e.g. >ABS<) and sometimes a
mixture of 2 materials (e.g. >ABS+PC<).
There are often fillers (T for Talcum powder, M for Mineral and G for Glass) and the
amount of filler as a percentage (e.g. >ABS-T20<, which means ABS with 20% talcum powder).
Plastics
Part numbers are necessary for identification of parts in production as well as for
maintenance and spare parts. Part numbers comprise a five, six or seven digit serial
number, e.g. 1234567-LH (part number - left-hand).
The marked date refers to the date of manufacture. The marked date often comprises
a date and a time or just a date field.
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Scania CV AB 2012, Sweden
Identification of materials
Plastics designations
>ABS<
Acrylonitrile butadiene styrene:
ABS is easy to recycle and can be mixed with PC to form PC+ABS after recycling,
which is advantageous since pure ABS can loose impact resistance when remelted.
>ASA<
Acrylonitrile styrene acrylate:
Used for A-pillar panels, windscreen wiper panels, hinge covers, rear view mirror
holders and roof hatch panels. Weather and colour resistant. Easy to recycle.
>EPDM<
Ethylene propylene diene monomer (rubber).
>HDPE<
High density polyethylene.
Plastics
>NR<
Nitrile rubber.
>PA<
Polyamide:
The designation is often followed by one of the figures 6, 6.6, 11 or 12. Used primarily for engine compartment components, compressed air and fuel pipes. Recycling
is limited by the availability of material. Material characteristics are not degraded
significantly if recycling takes the moisture problem into consideration.
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Identification of materials
>PBT<
Polybutyleneterephthalate:
Recycling is limited by the relatively small amount of available material and poor
availability of material data for recycled material.
>PMMA<
Polymethylmethacrylate:
Better known as plexiglas. Used primarily for covers for lighting and instruments.
Easy to recycle.
>PC<
Polycarbonate:
At Scania, PC rarely occurs in its pure form but often in combination with PBT or
ABS.
>PC+PBT<
A mixture of PC and PBT, combining the best characteristics from both materials.
The material is sensitive to moisture and high temperatures during production.
Plastics
Recycling is difficult to assess as the material degrades at high temperatures and after
exposure to moisture for long periods.
>PC+ABS<
Mixture of PC and ABS. Recycling is easier than PC+PBT and works well for material for simpler products.
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Identification of materials
>PE<
Polyethylene:
Several designations can occur depending on the density:
PE - LD where LD means Low Density
PE - HD where HD means High Density
Used for certain fuel tanks, etc. Polyethylene is the most recycled material in the
world. The material absorbs fuel which later, and if recycled, emits odour. Material
from fuel tanks should therefore undergo special treatment and be used for energy
recovery.
>PP<
Polypropylene.
Normally used for interiors, in low temperature applications around the engine and
even externally in some cases. PP is easy to recycle.
>PPO<
Polyphelylene oxide.
Plastics
>PUR<
Polyurethane (Thermosets):
Used in squab cushions, armrests and noise reduction mats. This material is difficult
to recycle at present.
>PVC<
Polyvinyl chloride:
Used for e.g. cable insulation. This material is difficult to recycle as it is sensitive to
impurities. In addition hydrochloric acid is created when burned.
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©
Scania CV AB 2012, Sweden
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