Claims
- 1. An improved, sound-attenuating cellular thermoplastic polymer foam body, the modified foam body having
a. an average cell diameter of at least one and one-half millimeters; and b. an impedance tube noise reduction coefficient of at least 0.3, wherein the improvement comprises at least one Helmholtz resonator, each Helmholtz resonator being disposed within the foam body, having a neck in fluid communication with an external surface of the foam body and being spaced apart from each other, whereby each Helmholtz resonator improves sound absorption coefficients about a Helmholtz center peak frequency band, such that at least one adjacent octave band has a sound absorption coefficient within 0.4 units of a peak sound absorption coefficient and increases the impedance tube noise reduction coefficient by at least 0.1 relative to the impedance tube average noise reduction coefficient of the same foam body without any Helmholtz resonators.
- 2. An improved, sound-attenuating cellular thermoplastic polymer foam body, the foam body having
a. an average cell diameter of at least one and one-half millimeters and b. an impedance tube average noise reduction coefficient of at least 0.3 wherein the improvement comprises at least one quarter wave attenuator, the attenuator(s) being spaced apart from each other and having a diameter that exceeds the average cell diameter, each attenuator beginning at a surface of the foam body and extending into, but not through, the foam body, whereby the quarter wave attenuator(s) increase(s) the impedance tube average noise reduction coefficient by at least 0.1 relative to the impedance tube average noise reduction coefficient of the same foam body without any quarter wave attenuator(s), and each quarter wave attenuator improves sound absorption coefficients about a quarter wave attenuator center peak frequency band, such that at least one adjacent octave band has a sound absorption coefficient within 0.4 units of a peak sound absorption coefficient.
- 3. The foam body of claim 1, wherein the foam body also comprises at least one quarter wave attenuator, the attenuator(s) being spaced apart from each other and having a diameter that exceeds the average cell diameter, each attenuator beginning at a surface of the foam body and extending into, but not through, the foam body, whereby the quarter wave attenuator(s) increase(s) the impedance tube average noise reduction coefficient by at least 0.1 relative to the impedance tube average noise reduction coefficient of the same foam body without any quarter wave attenuator(s), and each quarter wave attenuator improves sound absorption coefficients a quarter wave attenuator center peak frequency band, such that at least one adjacent octave band has a sound absorption coefficient within 0.4 units of a peak sound absorption coefficient.
- 4. The foam body of claim 1, claim 2, or claim 3, wherein the foam body further comprises one or more surface modifications selected from wedge-shaped indentations, polyhedral indentations, and incisions that penetrate the surface of the body, but do not extend through the body.
- 5. The foam body of claim 1, claim 2, or claim 3, wherein the average cell diameter is greater than or equal to four millimeters.
- 6. The foam body of claim 4, wherein the average cell diameter is greater than or equal to four millimeters.
- 7. The foam body of claim 1, claim 2, or claim 3, wherein the average cell diameter is greater than or equal to six millimeters.
- 8. The foam body of claim 4, wherein the average cell diameter is greater than or equal to six millimeters.
- 9. The foam body of claim 1, claim 2, or claim 3, wherein the thermoplastic polymer is a low density polyethylene resin, a polypropylene resin or a blend of a low density polyethylene resin and a polypropylene resin, or a combination of any of the above with an ethylene styrene interpolymer.
- 10. The foam body of claim 4, wherein the thermoplastic polymer is a low density polyethylene resin, a polypropylene resin or a blend or a low density polyethylene resin and a polypropylene resin, or a combination of any of the above with an ethylene styrene interpolymer.
CROSS REFERENCE STATEMENT
[0001] This application claims the benefit of U.S. Provisional Application No. 60/267,533, filed Feb. 9, 2001.
Provisional Applications (1)
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Number |
Date |
Country |
|
60267533 |
Feb 2001 |
US |