Polyurethane Foams for Acoustic Applications
|Publication Date:||1 September 2021|
Note: Nothing in this standard supercedes applicable laws and regulations.
Note: In the event of conflict between the English and domestic language, the English language shall take precedence.
This specification identifies polyester and polyether urethane types of sound absorbing foams used in General Motors vehicles. This specification will include both molded and flat stock foams.
This specification shall encompass polyurethane foams used for acoustical applications throughout the vehicle. These polyurethane foams may be used for vibration damping, noise and shock isolation, and spacers for part retention with acoustical requirements.
Products qualified to this specification shall be identified by compression force deflection ranges per ISO 3386 at 40% compression as follows:
• Type 1: 2 kPa to 25 kPa, see 1.4.1
• Type 2: 25 kPa to 50 kPa, see 1.4.2
• Type 3: 50 kPa to 99 kPa, see 1.4.3
• Type 4: 100 kPa to 175 kPa, see 1.4.4
• Type 5: 175 kPa to 450 kPa, see 1.4.5
• Type 6: 450 kPa to 850 kPa, see 1.4.6
• Type 7: See 1.4.7
Type 1. This is a low modulus (soft cellular) foam which can be easily compressed and used for sound absorption, isolation and air and dust seals.
Type 2. This is a low modulus with a slightly higher tensile strength than Type 1. This type may also be used for sound absorption, isolation and air and dust seals.
Type 3. This is a slightly firmer foam which are recommended for sound absorption, noise and shock isolation, air and dust seals.
Type 4. This is a firm but compressible foam material and is recommended for sound absorption, noise and shock isolation, air and dust seals.
Type 5. This is a firmer foam than Type 4 foam yet with yielding higher compression. This type can be used for sound absorption, noise and shock isolation, spacers for part retention and air and dust seals.
Type 6. This is a very firm foam with high compression. This type can be used for sound absorption, noise and shock isolation, spacers for part retention and air and dust seals.
Type 7. Foams for this type will also be used for sound absorption, isolation, and air and dust seals, but will have unique properties which will distinguish them from the other foam types. Compression Force Deflection, Density and any other unique properties pertinent to the performance of the foam, for its specific application shall be called out on the print or the math file.
Recycled polyurethane materials or bio-based materials may be used for parts under this specification. Prior to incorporating recycled or bio-based materials into a finished product, the supplier shall provide data to GM Materials Engineering showing that no decrease in performance or durability will occur due to the use of the recycled polyurethane materials or bio-based materials.