Enhancement of Dimensional Stability of Compressed Open Cell Rigid Polyurethane Foams by Thermo-Mechanical Treatment

  • Ahn, WonSool (Department of Chemical Engineering, Keimyung University)
  • Received : 2015.02.02
  • Accepted : 2015.02.25
  • Published : 2015.03.31


Thermo-mechanical treatment process of a compressed open-cell rigid polyurethane foam (OC-RPUF), which was fabricated for the vacuum insulation panel (VIP), was studied to obtain an optimum condition for the dimensional stability by the relaxation of compressive stress. Thermo-mechanical deformation of the sample OC-RPUF was shown to occur from about $120^{\circ}C$. Yield stress of 0.36 MPa was shown at about 10% yield strain. And, densification of the foam started to occur from 75% compressive strain and could be continued up to max. 90%. Compression set of the sample restored after initial compression to 90% at room temperature was ca. 82%. Though the expansion occurred to about twice of the originally compressed thickness in case of temperature rise to $130^{\circ}C$, it could be overcome and the dimensional stability could be maintained if the constant load of 0.3 MPa was applied. As the result, a thermo-mechanical treatment process, i.e, annealing process at temperature of $130{\sim}140^{\circ}C$ for about 20 min as is the maximum compressed state at room temperature, should be required for dimensional stability as an optimum condition for the use of VIP core material.


  1. G. Oertel, "Polyurethane Handbook", 2nd ed, Hanser Publishers, N. Y., Ch. 6, 247 (1993).
  2. M. Szycher, "Szycher's Handbook of Polyurethanes", CRC Press, N. Y., Ch. 8, 1 (1999).
  3. D. Randall and S. Lee, "The polyurethanes book", John Wiley? Sons, Ltd., N. Y., Ch. 15, 229 (2002).
  4. K. Yoshida, "Polyurethane and Related Foams", CRC Press, FL, Ch. 4, 65 (2007).
  5. U. Henri, "Chemistry and Technology of Isocyanate", John Wiley & Sons, N. Y., Ch. 2, 469 (1996).
  6. A. Biedermann, C. Kudoke, A. Merten, E. Minogue, U. Rotermund, H.-P. Ebert, U. Heinemann, J. Fricke, and H. Seifert, "Analysis of Heat Transfer Mechanisms in Polyurethane Rigid Foam", J. Cellular Plast., 37, 467 (2001).
  7. T. Widya and C. W. Macosko, "Nanoclay-Modified Rigid Polyurethane Foam", J. Macromol. Sci., Part B: Phys., 44, 897 (2005).
  8. Takeda Chemical Industries, Ltd, "Production and Use of Open Cell Rigid Polyurethane Foam", U.S Patent No. 5,350,777 (1999).
  9. X. D. Zhang, H. T. Davis, and C. W. Macosko, "A New Cell Opening Mechanism in Flexible Polyurethane Foam", J. Cellular Plast., 35, 458 (1999).
  10. J. Fricke, U. Heinemann, and H. P. Ebert, "Vacuum insulation panels - From research to market", Vacuum, 82, 680 (2008).
  11. Samsung Electronics Co. Ltd., "Open Cell Rigid Polyurethane Foam and Method for Producing the Same and Method for Making Vacuum Insulation Panel Using Same", U.S Patent No. 5,889,067 (1999).
  12. T. Heinemann and W. Klan, "Fine Cell, Water-Blown Rigid Polyurethane Foams", U.S 2005/0014857 A1 (2005).
  13. J.-W. Wu and H.-S. Chu, "Heat transfer in open cell polyurethane foam insulation", Heat Mass Transfer, 34, 247 (1998).