Claims
- 1. A cellular thermoplastic polymer foam having an average cell size of at least about 1.5 mm, a density not greater than about 300 kg/m3, an average sound absorption coefficient of at least about 0.2, and a heat distortion temperature of at least about 110 degrees Celsius, wherein the thermoplastic polymer comprises:
(A) at least one predominantly isotactic, propylene polymer having a tan δ value not greater than 1.5 and optionally (B) at least one ethylene polymer produced via a free radical process blended with the propylene polymer, wherein the thermoplastic polymer foam satisfies at least one of the following three conditions: the thermoplastic polymer comprises ethylene polymer blended with the propylene polymer and the weight ratio of the propylene polymer (A) to the ethylene polymer (B) is at least about 35:65; the foam has at least one surface, the at least one surface having defined therein a multiplicity of perforation channels extending from the at least one surface into the foam such that there is an average of at least one perforation channel per 10 square centimeters of the at least one surface and/or the foam has a density less than 25 kg/m3.
- 2. The foam of claim 1 having an open cell content of less than 50 percent measured according to ASTM D2856-A.
- 3. The foam of claim 2 having an open cell content not greater than 20 percent measured according to ASTM D2856-A.
- 4. The foam of claim 1 wherein the foam has the perforation channels and the perforation channels have an average diameter at the at least one surface of 0.1 mm.
- 5. The foam of claim 4 wherein the at least one surface has an average of at least 10 perforation channels per 10 square centimeters extending from the at least one surface into the foam.
- 6. The foam of claim 1 having an average cell size of at least about 5 mm and a density not greater than about 60 kg/m3.
- 7. The foam of claim 1 having an average sound absorption coefficient of at least about 0.3.
- 8. The foam of claim 1 having a heat distortion temperature of at least about 140 degrees Celsius.
- 9. The foam of claim 1 having a water absorption not more than 10 percent by volume measured according to European Norm 12088 at 50 degrees Celsius based on a test period of 14 days exposure.
- 10. The foam of claim 1, wherein the at least one ethylene polymer is selected from the group consisting of low density polyethylene (LDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), and ethylene-acrylic acid copolymer (EAA).
- 11. A process for making polymer foams useful for sound absorption in an elevated temperature and/or moist environment comprising converting a foamable composition comprising at least one blowing agent and at least one thermoplastic polymer into a cellular polymer foam having an average cell size of at least 1.5 mm, a density not greater than 300 kg/m3, and at least one surface, the thermoplastic polymer comprising:
(A) at least one predominantly isotactic, propylene polymer having at least one of (1) a tan δ value not greater than 1.5, (2) a melt tension of at least 7 centiNewtons (cN), and/or (3) a melt strength of at least 10 centiNewtons (cN) and optionally (C) at least one ethylene polymer produced via a free radical process blended with the propylene polymer, wherein the process further satisfies at least one of the following three additional conditions: (1) selecting as the thermoplastic polymer a polymer blend comprising ethylene polymer blended with the propylene polymer such that the weight ratio of the propylene polymer (A) to the ethylene polymer (B) is at least 35:65; (2) perforating at least one surface of the cellular polymer foam product to introduce a multiplicity of perforation channels extending from the at least one surface into the foam such that there is an average of at least one perforation channel per 10 square centimeters of the at least one surface and/or (3) selecting conditions for converting the foamable composition into the cellular polymer foam such that the cellular polymer foam has a density less than 25 kg/m3.
- 12. A process for making polymer foams comprising:
(A) providing a cellular polymer foam having an average cell size of at least 1.5 mm, a density not greater than 300 kg/m3, an average sound absorption coefficient of at least 0.2, a heat distortion temperature of at least 110 degrees Celsius, and at least one surface wherein the polymer comprises:
(1) at least one predominantly isotactic, propylene polymer having at least one of a tan δ value not greater than 1.5, a melt tension of at least 7 centiNewtons (cN) and/or a melt strength of at least 10 centiNewtons (cN) and optionally (2) at least one ethylene polymer produced via a free radical process blended with the propylene polymer, and (B) perforating the at least one surface of the polymer foam of step (A) so as to form a multiplicity of perforation channels extending from the at least one surface into the foam such that there is an average of at least one perforation channel per 10 square centimeters (cm2) area of the at least one surface.
- 13. The process according to claim 11, wherein the perforation channels have an average diameter at the at least one surface of 0.1 mm.
- 14. The process according to claim 12, wherein the perforation channels have an average diameter at the at least one surface of 0.1 mm.
- 15. The process according to claim 11, wherein the at least one surface has an average of at least 10 perforation channels per 10 square centimeters extending from the at least one surface into the foam.
- 16. The process according to claim 12, wherein the at least one surface has an average of at least 10 perforation channels per 10 square centimeters extending from the at least one surface into the foam.
- 17. The process according to claim 11, wherein the polymer foam before perforation has an open cell content, measured according to ASTM D2856, Procedure A, not greater than about 40 percent and the polymer foam after perforation has an open cell content, measured according to ASTM D2856, Procedure A, of at least 20 percent and at least 10 percent greater than the open cell content, measured according to ASTM D2856, Procedure A, of the polymer foam prior to perforation.
- 18. The process according to claim 12, wherein the polymer foam before perforation has an open cell content, measured according to ASTM D2856, Procedure A, not greater than about 40 percent and the polymer foam after perforation has an open cell content, measured according to ASTM D2856, Procedure A, of at least 20 percent and at least 10 percent greater than the open cell content, measured according to ASTM D2856, Procedure A, of the polymer foam prior to perforation.
- 19. The process according to claim 11, wherein the polymer foam has an average cell size of at least about 5 mm and a density not greater than about 60 kg/m3.
- 20. The process according to claim 12, wherein the polymer foam has an average cell size of at least about 5 mm and a density not greater than about 60 kg/m3.
- 21. The process according to claim 11, wherein the at least one ethylene polymer is selected from the group consisting of low density polyethylene (LDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), and ethylene-acrylic acid copolymer (EAA).
- 22. The process according to claim 12, wherein the at least one ethylene polymer is selected from the group consisting of low density polyethylene (LDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), and ethylene-acrylic acid copolymer (EAA).
- 23. The process according to claim 11, wherein the polymer further comprises a substantially random interpolymer.
- 24. The process according to claim 12, wherein the polymer further comprises a substantially random interpolymer.
- 25. A cellular polymer foam obtainable by the process according to claim 11.
- 26. A cellular polymer foam obtainable by the process according to claim 12.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional Application No. 60/190,714 filed on Mar. 17, 2000, and U.S. Provisional Application No. 202,364 filed on May 5, 2000.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60190714 |
Mar 2000 |
US |
|
60202364 |
May 2000 |
US |