VW TL 52722 Polyether PUR Foam in Engine Compartment - Material Requirements

The standard “VW TL 52722 Polyether PUR foam in the engine compartment - Material requirements”, developed by the Volkswagen automobile company, describes the material requirements for polyether PUR foam parts with sound-insulating properties in the engine compartment, used, for example, to reduce noise from the engine.

In this technical supply specification the basic requirements are given as follows:

• Approval of initial supply and changes according to VW 01155 standard.
• Resistance to outdoor weathering according to VW 50185 standard.
• Prevention of hazardous substances in accordance with the VW 91101 standard.
• Tests should be performed on samples made from finished parts.
• If tests cannot be performed on samples taken from the component due to geometry, measurements can be made on test sheets. A minimum of 1 m2 of sheet material or at least 5 molded parts are required for a full test.
• All mechanical tests are preferably carried out on skinless samples taken from finished parts. All other tests are preferably carried out on samples taken from the component. The test sheets must have a comparable surface. The surface type must be stated in the test report.
• Polyether PUR foam must have a uniform cellular structure.
• Molded parts must maintain their dimensional and functional integrity during transportation, storage, assembly and subsequent use in the temperature range of minus 40 degrees to the defined upper limit, as well as in climatic conditions of 90 degrees Celsius and 100 percent relative humidity. Different requirements regarding temperature and environmental resistance, if any, must be defined in the drawing and verified by additional tests.
• Deviations from the material structure, such as the addition of nonwoven covers or aluminum heat shields, require approval from the relevant Development department and the relevant Materials Engineering department. Deviations from the standard must be recorded separately on the drawing in writing.
• The different requirements should be obtained from the relevant component drawings.
• Inspections should start no later than 72 hours after foaming. Before testing, samples must be conditioned for at least 50554 hours in a 23/50-2 standard atmosphere according to VW 24.
• The required numerical values ​​apply to each measurement.
• The materials and manufacturing processes used for semi-finished products and foam processing must be specified to the relevant materials engineering department and always included in the initial sample inspection reports.
• Acoustic requirements must be agreed upon with the relevant department. The appropriate department must be indicated on the drawing.
• According to the German Automotive Industry Association VDA 260 standard, the marking must be "PUR".

Gross density is determined according to DIN EN ISO 845. For moulded parts, samples should be taken from flat areas with smooth surfaces.

Compressive stress,

• According to DIN EN ISO 250-3 for foam with a gross density of up to 3386 kg/m1 and
• According to DIN EN ISO 250-3 standard for foam with a gross density equal to or greater than 3386 kg/m2,

at 40 percent deformation and refers to the evaluation of initial compression.

The samples shall be aged in a compressed air oven. The test shall be carried out on test samples of at least 500 mm × 500 mm or on the finished part.

In heat and humidity aging, the samples are placed on a perforated plate in a 10-liter desiccator, the water content is about 1 l. Different from these specifications, aging can be done in the climate chamber. The variant used must be stated in the test report.

The compression test must be carried out in accordance with DIN EN ISO 1856 standard method A. Samples are taken from the finished part or from the supplied sheets. The compression for the test is 50 percent plus/minus 4 percent. The measurement is made 30 minutes after the load is removed.

The liquid repellency test is carried out in accordance with the PV 3922 standard. The test is carried out on finished parts or sections of finished parts with a minimum size of 200 mm × 200 mm. They must have leather on them. The following types of liquids should be used:

• Deionized water
• Reference engine oil in accordance with TL 52185 standard
• According to TL 774-G standard, the coolant additive to water ratio is 50:50.

Before testing the liquid repellent properties, the samples must be acclimatized for 50554 hours in a standard atmosphere according to VW 23 standard 50/2-24.

To determine the dimensional stability of the component, measurement points are applied in the longitudinal and transverse directions. The distance between them is measured before aging. Another measurement is taken after aging. The dimensional change should be measured on the finished part. The measurement should be made after low-temperature aging while the sample is frozen.

Among the numerous tests, measurements, analyses and evaluation studies carried out for businesses in various sectors, our organization also provides testing services defined in the “VW TL 52722 Polyether PUR foam in the engine compartment - Material requirements” standard with its trained and expert staff and advanced technological equipment.