Group standard TL 669
Issue 2015-11
Class. No.: 55121
Descriptors: PE, polyethylene, plastic fuel tank, plastic tank, fuel tank, extrusion blow molding method
High-Molecular-Weight Polyethylene, Finished Parts
Materials Requirements
4 Types: Without Index, A, B, C
Previous issues
TL 669: 1973-11, 1976-03, 1985-10, 1987-09, 1995-05, 2002-12, 2008-09
Changes
The following changes have been made to TL 669: 2008-09:
– Technical responsibility updated
– Applicable documents updated
– "D" marking for feature(s) subject to mandatory documentation removed
1 Scope
This Technical Supply Specification defines the material requirements for finished parts made from
high-molecular-weight polyethylene (PE), e.g., plastic fuel tanks and associated add-on and instal‐
lation parts.
2 Designation
Designation example for the type manufactured according to the Phillips polymerization process:
High-molecular-weight PE as per TL 669
Always use the latest version of this standard.
This electronically generated standard is authentic and valid without signature. Page 1 of 6
The English translation is believed to be accurate. In case of discrepancies, the German version is alone authoritative and controlling.
Technical responsibility The Standards department
GQL-P/2 Dr. Lars Fölster Tel.: +49 5361 9 24850 EKDV/4 Stefanie Reiss EKDV
GQL-P Dr. Jiping Liu Tel.: +49 5361 9 41184 Maik Gummert
All rights reserved. No part of this document may be provided to third parties or reproduced without the prior consent of one of the Volkswagen Group’s Standards departments.
© Volkswagen Aktiengesellschaft VWNORM-2015-07d
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TL 669: 2015-11
3 Requirements
3.1 General requirements
Approval of first supply and changes as per VW 01155.
Emission behavior as per VW 50180, if required in the drawing.
Resistance to open-air weathering as per VW 50185.
Avoidance of hazardous substances as per VW 91101.
For plastic fuel tanks, 1 finished part is required for complete testing; for smaller finished parts,
10 parts are required.
3.2 Properties
The surface and interior (e.g., walls of the tank) of the finished parts must not have any flaws such
as cracks, blisters, voids, areas with an increased stress concentration, foreign inclusions, and/or
molding material particles that are insufficiently molten down during processing.
Parts manufactured by means of injection molding, e.g., plastic fuel tank add-on and installation
parts, must furthermore be free of flow lines and microstructural inhomogeneities, such as film and
layer formation ("puff pastry" texture).
3.3 Human compatibility
The materials used must be physiologically safe. Substances that are emitted at elevated tempera‐
tures must be toxicologically safe.
3.4 Manufacture
Extrusion blow molding or injection molding method
3.5 Types
– TL 669 High-molecular-weight PE, manufactured according to the Phillips polymeri‐
zation process; suitable for the extrusion blow molding method.
– TL 669-A High-molecular-weight PE, manufactured according to the Ziegler polymeri‐
zation process; suitable for the extrusion blow molding method.
– TL 669-B High-molecular-weight PE, manufactured according to the Phillips polymeri‐
zation process; suitable for the injection molding method.
– TL 669-C High-molecular-weight PE, manufactured according to the Ziegler polymeri‐
zation process; suitable for the injection molding method.
3.6 Marking as per VDA 260
All types: > PE-HD <
3.7 Conditioning
Prior to testing, the specimens required for the individual tests must be conditioned for at least 48 h
in standard atmosphere as per VW 50554 – 23/50.
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TL 669: 2015-11
3.8 Evaluation of the measurement results
Unless otherwise noted, the required numerical values apply to each individual measurement and
to every point on the finished part.
4 Materials requirements
4.1 Material
See section 6.1.
All types: High-molecular-weight PE with stabilizer additive to protect against oxidation and aging.
4.2 Color
As per drawing. Coloring must be uniform throughout.
5 Required properties
See table 1.
Table 1
No. Property Unit Requirement
TL 669 TL 669-A TL 669-B TL 669-C
1 Density g/cm 3
0.943 to 0.940 to 0.938 to 0.947 to
as per DIN EN ISO 1183-1, method A 0.948 0.946 0.945 0.952
2 Melting index g/10 min 3 to 7 5 to 10 10 to 18 10 to 16
as per DIN EN ISO 1133-1, method A, Code G
190 °C; 21.6 kg
3 Melting temperature °C 131 ±2 130 ±2
as per ISO 11357-3
4 Hardness Shore D 64 ±2 63 ±2 60 ±2
as per DIN ISO 7619-1, measurement time: 3 s (inner side (inner side
of tank) of tank)
5 Yield stress as per DIN EN ISO 527-2 and MPa - ≥20 ≥24
section 6.2
5.1 In direction of extrusion MPa
≥20 ≥19 -
5.2 Crosswise to the direction of extrusion MPa
6 Elongation at yield as per DIN EN ISO 527-2 and % - 9 to 15
section 6.2
6.1 In direction of extrusion %
9 to 15 -
6.2 Crosswise to the direction of extrusion %
7 For behavior at higher deformation rate, see section 6.3
for type approval, see section 6.9
7.1 In direction of extrusion mm
≥20 -
7.2 Crosswise to the direction of extrusion mm
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TL 669: 2015-11
No. Property Unit Requirement
TL 669 TL 669-A TL 669-B TL 669-C
8 High-temperature behavior No embrittlement; no change in shape that would
as per DIN 53497 and section 6.4 impair performance; no color change or surface
change.
9 Maximum shrinkage, see section 6.5
9.1 In direction of extrusion %
≤3.5 -
9.2 Crosswise to the direction of extrusion %
10 Low-temperature behavior The finished parts must be fully functional at low
see section 6.6 temperatures and must not exhibit cracks or other
damage even after the temperature has been
raised to 23 °C (for additional requirements, see
drawing).
11 Stress crack resistance ≥1 000 h without cracks
see section 6.7
12 Lightfastness The light-exposed surface must not exhibit changes
as per PV 1303 and section 6.8 as compared to the as-received condition, such as
(requirement applies only to visible parts in the a color change, chalking, and/or cracking. Gray-
vehicle interior or, if required, in the drawing). scale level 4 as per DIN EN 20105-A02
Number of exposure periods as per drawing.
13 Flammability as per TL 1010 (if required in drawing and/or re‐
lease).
6 Notes on testing
6.1 Material
The identity test can be performed by infrared spectroscopy or thermal analysis.
6.2 Yield stress and elongation at yield
Tensile test as per DIN EN ISO 527-2, specimen type 5A, test speed: 50 mm/min.
6.3 Behavior at higher deformation rate
Fast tensile test on tensile impact specimens as per DIN EN ISO 8256, type 3; free clamping
length of 40 mm; test speed of (6 ±0.1) m/s; test equipment e.g. Zwick universal testing machine,
type REL 1852.
The change in the length of the specimens must be determined at a drop in force of 90% (= ma‐
chine setting for fracture recognition).
At least 5 specimens, each from flat areas (in fuel tanks, preferably from the bottom area), must be
tested.
6.4 High-temperature behavior
Heat aging test as per DIN 53497, method B, on at least two complete finished parts; aging tem‐
perature: (90 ±1) °C; aging duration: 22+2
-0 h.
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TL 669: 2015-11
6.5 Maximum shrinkage
Heat aging test as per DIN 53497, method B, on square cutouts with an edge length of 50 mm.
The cutouts must be taken from the blow-molded part in such a way that two parallel edges of the
square run exactly in the direction of extrusion.
The edges of the cutouts must be measured to an accuracy of 0.1 mm before and after aging.
A minimum of three specimens must be tested.
Aging duration: 2+0.5
-0 h; aging temperature: (128 ± 1) °C.
6.6 Low-temperature behavior
At least one complete finished part must be aged in air at (-40 ±1) °C; aging duration: 22+2
-0 h.
6.7 Stress crack resistance
The components must be equipped with original installation and add-on parts (e.g., pump, cover)
and installed in this condition in a test fixture that simulates exactly the as-installed position in the
vehicle.
The tanks must be filled according to their nominal volume with a 10% aqueous solution of a non-
ionogenic wetting agent (e.g., "Lutensol FSA 10," made by BASF AG) and then be aged in a
forced-air oven at (80 ±1) °C.
Individual parts are immersed in the solution.
The devices under test are visually evaluated after the prescribed test duration has elapsed.
A minimum of three parts must be tested.
6.8 Lightfastness
If the number of periods of exposure is not defined in the drawing, the following rule applies:
– 3 periods of exposure for components in areas subject to indirect solar radiation
– 5 periods of exposure for components in areas subject to direct solar radiation (e.g., door waist
rail)
– 10 periods of exposure for components in areas subject to maximum solar radiation (e.g., rear
shelf).
6.9 Type approval
This requirement applies to new-sample inspections and initial sample inspections (basic test of
material suitability). Volkswagen AG reserves the right to also apply this requirement to the evalua‐
tion of production deliveries.
7 Applicable documents
The following documents cited in this standard are necessary to its application.
Some of the cited documents are translations from the German original. The translations of Ger‐
man terms in such documents may differ from those used in this standard, resulting in terminologi‐
cal inconsistency.
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TL 669: 2015-11
Standards whose titles are given in German may be available only in German. Editions in other
languages may be available from the institution issuing the standard.
PV 1303 Non-Metallic Materials; Xenon Arc Light Aging of Vehicle Interior Com‐
ponents
TL 1010 Materials for Vehicle Interiors; Burning Behavior; Material Requirements
VW 01155 Vehicle Parts; Approval of First Supply and Changes
VW 50180 Components in the Vehicle Interior; Emission Behavior
VW 50185 Vehicle Parts; Resistance to Open-Air Weathering
VW 50554 Standard Atmospheres and Room Temperatures; Requirements on
Standard Atmospheres
VW 91101 Environmental Standard for Vehicles; Vehicle Parts, Materials, Operat‐
ing Fluids; Avoidance of Hazardous Substances
DIN 53497 Testing of Plastics; Hot Storage Test on Mouldings Made of Thermo‐
plastic Moulding Materials without External Mechanical Stressing
DIN EN 20105-A02 Textiles - Tests for colour fastness - Part A02: Grey scale for assessing
change in colour
DIN EN ISO 1133-1 Plastics - Determination of the melt mass-flow rate (MFR) and melt vol‐
ume-flow rate (MVR) of thermoplastics - Part 1: Standard method
DIN EN ISO 1183-1 Plastics - Methods for determining the density of non-cellular plastics -
Part 1: Immersion method, liquid pyknometer method and titration meth‐
od
DIN EN ISO 527-2 Plastics - Determination of tensile properties - Part 2: Test conditions for
moulding and extrusion plastics
DIN EN ISO 8256 Plastics - Determination of tensile-impact strength
DIN ISO 7619-1 Rubber, vulcanized or thermoplastic - Determination of indentation hard‐
ness - Part 1: Durometer method (Shore hardness)
ISO 11357-3 Plastics - Differential scanning calorimetry (DSC) - Part 3: Determination
of temperature and enthalpy of melting and crystallization
VDA 260 Components of motor vehicles - Marking of material
