VW TL 52671 Outdoor High Gloss Plastics (Except ASA) - Component Related Material Requirements

The “VW TL 52671 High-gloss plastics for exterior applications (excluding ASA) - Component-related material requirements” standard, developed by the Volkswagen automotive company, describes the component-related material requirements for unpainted, high-gloss plastic coated parts made of polymethyl methacrylate or modified polymethyl methacrylate (with impact resistance modifications), polymethyl methacrylate containing acrylonitrile-butadiene styrene as a carrier material, and similar materials, for exterior applications (e.g., exterior A, B and C pillar trims, side spoilers, bumper grilles). Parts made of acrylic-styrene-acrylonitrile for these applications are tested according to the VW 52311 Technical supply specification.

According to this standard, the general requirements are determined as follows:

• Initial supply and approval of changes must comply with the VW 01155 standard.
• Granular material must comply with VW 50026 standard.
• Outdoor weatherability must comply with VW 50185 standard.
• Material sample inspection must comply with the VW 52000 standard.
• Material and chemical compatibility must comply with VW 91101 standard.
• Thermal stability and functional capacity should be in the temperature range of minus 30 degrees to 90 degrees.

In this standard, the types are determined as follows:

• TL 52671-A Trim panels, emblems with high gloss appearance, for single component injection molding without increased strength requirements.
• TL 52671-B Trim panels are for side spoilers alternatively bonded to the carrier part for two-component injection molding without increased strength requirements.
• TL 52671-C Components in the front and rear end area (e.g. bumper grille) have increased impact resistance requirements.

The technological properties of the materials used in the parts must ensure their function and safety throughout the entire service life of the vehicle. Modifiers for heat and ultraviolet (UV) stabilization must be used in sufficient quantities, if not already present in the final compound, depending on the type and demands of the application.

In the case of parts made of composite materials (metal/plastic, adhesive bonds, hard/soft combination), compatibility of the materials must be ensured. If necessary, the materials must be made compatible with each other through pretreatments (e.g. binders).

The description of the relevant material requirements for the part is given in the table titled “Requirement categories”. The tables titled “Material requirements for types A and B” and “Material requirements for type C” refer to the basic material composition (in this case polymethyl methacrylate) and do not refer to defined commercial types. The requirements in the target specifications are decisive. They are used as the basis for the material release of commercial types. Therefore, products should be selected whose data sheet values ​​of the relevant commercial type correspond at least to the relevant type in this standard.

When describing material requirements, each type (A, B and C) is divided into five requirement categories:

• Material quality: Material quality includes information about the actual material and material changes required to essentially ensure the functionality of the part. It also includes examples for drawing text.
• Material reference values: Material reference values ​​are used to better assess the effect of the material on processing, since the wall thickness has no or only a minor effect on the calculation of mechanical properties (e.g. by adapting the support spacing). Furthermore, the properties determined there should help to establish the material characteristic values. The closer the properties of the samples from the relevant part are to the raw material data sheet of the manufacturer, the better the production process. The aim is always to be as close as possible to the characteristic values ​​in the material data sheet, as long as the necessary data are available there.
• Part-related material properties: Here, the actual properties of the material related to the part design (e.g. effect of wall thickness in the ball drop test) are reproduced.
• Surface quality: Surface quality is only taken into account for uncoated finished parts if areas of these parts are directly visible. For high-gloss applications, the VW TL 52726 standard must also be followed. Surface quality is only assessed during the production process and when the product is launched, as it has no functional or safety relevance. However, for a timely assessment, weatherability tests should be started at an early stage due to the long test times. Even in an early test, the surface structure must correspond to the structure used later.
• Potential use of recycled materials: This section describes what type of recycled material can be used for the specific application and whether it can be used. The selection should be compared with the VW 50026 standard.

Material requirements are determined as follows depending on the area of ​​use:

• Unlisted materials apply to all materials that are not on the material approval list according to this standard. It also applies to recycled materials.
• Materials on the material approval list, reduced testing program, only a few selected tests are still required. Tests may vary depending on the application. Also valid for recycled materials.
• For recycled materials (batch-related testing), batch-related testing is required in addition to the normal testing program. This testing may vary depending on application requirements.

The tables titled “Material requirements for types A and B” and “Material requirements for type C” contain the tests required in each case.

Our organization, which has been trying to support businesses from every sector with its testing, measurement, analysis and evaluation studies carried out in a wide range for years, has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. In this context, testing services are also provided to businesses in accordance with the standard “VW TL 52671 High gloss plastics for exterior use (excluding ASA) - Component-related material requirements”.