Hyundai Kia MS341-12 Material Specification - Sound Absorber - Engine Compartment

The standard “Hyundai Kia MS341-12 Material specification - Sound absorber - Engine compartment” developed by Hyundai Motor Company applies to sound absorbers laminated with protective coatings such as non-woven fabric, plastic film for use in automobile engine compartments and covers the use of an underbody and oil pan cover that provides sound absorption or insulation.

This material is classified as follows in the table given in the standard:

• Type A: Felts, glass wool, polyurethane foam
• Type B: Aramid nonwoven fabrics with epoxy resin binder
• Type C: Polyester microfiber and polyester non-woven fabrics
• Type D: Compressed polyester felt (sound absorption or insulation underbody and oil pan cover use)

Polyester microfiber is a polyester fiber produced by melt blowing process. Compressed polyester felt is a blend of 60 percent recycled polyester fiber (fiber thickness 15 De, fiber length 64 mm) and 40 percent low melting point polyester fiber (fiber thickness 4 De, fiber length 51 mm).

The requirements in this standard are described as follows:

• General requirements: Parts using this material must comply with all requirements of the relevant assembly performance specification. The chemical composition and processing condition should not be changed inappropriately, which may affect the quality of the parts. Before changing the chemical composition of the material, it is necessary to consult with the material and quality control department.

The appearance should comply with the requirements in the table given in the standard. There should be no excessive differences from the samples prepared according to the agreement between the parties in terms of appearance, color, brightness, touch (feel) and similar points. There should be no defects that may affect usability in terms of defect, deformation, stickiness, foreign matter, skin peeling.

Shape and size must conform to drawing specification.

Sound absorbers and skins must be constructed as otherwise specified and free from defects such as breaks, wrinkles, etc.

• Detailed requirements: The sound absorber shall be tested using the test methods specified in this standard and shall comply with the requirements in the table given in the standard. Samples shall be subjected to the same treatment as the parts.

The standard condition of the laboratory where the tests are carried out is 23 degrees plus/minus 2 degrees temperature and 50 percent plus/minus 5 percent relative humidity.

All tests are carried out on specimens at least 48 hours after moulding and immediately following a conditioning period of at least 24 hours in the standard condition specified in this standard. Thickness not specified, type B has a thickness of 2 mm and type D has a thickness of 3 mm.

Test methods described in this standard include:

• Weight test: For Type A, B, C, samples are randomly cut to 300 x 300 mm. For Type D, samples are randomly cut to 150 x 150 mm. Weight and average weight per square meter are stated. At least 5 test samples should be used and average values ​​should be reported.
• Thickness test: A 100 x 100 mm sample is placed on the horizontal plane of an anvil. A 150 x 120 mm press plate weighing 120 g is placed on the sample and pressed. After ten seconds, the gap between the press plate and the anvil is measured using a caliper. The average shall be considered as the thickness. At least 5 test samples shall be used and the average values ​​shall be reported.
• Normal condition test: For type AB C, dumbbell sample No. 1 is randomly prepared. In the normal condition specified in this standard, tension is applied at a rate of 200 mm per minute and the tensile strength is determined. For type D, the knitting method (A method) described in Hyundai Kia MS300-32 standard should be followed. At least 5 test samples should be used and the average values ​​should be reported.
• Heat aging resistance (long-term) test: Five No. 1 dumbbell samples are randomly prepared for Type A, B, C. They are aged for 200 hours at a specified temperature. The samples are kept in the standard state for 60 minutes. Tension is applied at a rate of 200 mm per minute and the tensile strength is determined. For Type D, the knitting method (A method) described in the Hyundai Kia MS300-32 standard should be followed. They are aged for 50 hours at a specified temperature. The samples are kept in the standard state for 1 hour. Tension is applied at a rate of 200 mm per minute and the tear strength is determined. At least 5 test samples should be used and the average values ​​should be reported.
• Heat aging resistance (short term) test: Dumbbell sample No. 1 is randomly prepared. Aged for 30 minutes at a specified temperature. Samples are kept in their standard condition for 60 minutes. Tension is applied at a rate of 200 mm per minute and tensile strength is determined. At least 5 test samples should be used and average values ​​should be reported.

This standard also describes the following test methods:

• Weather resistance test:
• Oil resistance test
• Heat shrinkage test
• Low temperature resistance test
• Water content recovery test
• Sound absorption test

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