| 摘要 |
Low-density, high service temperature polymer foam is extruded by heating a crystalline polymer resin above its crystalline melt point to melt the resin, selecting a blowing agent combination, combining the blowing agent combination with the resin to create a mixture, cooling the mixture to a temperature approaching a freezing temperature for the mixture, and extruding the foam through a die. The blowing agent combination is made up of 50 to less than 100 mole percent of a first blowing agent having a boiling temperature at STP of greater than 310 DEG K, and more than 0 to 50 mole percent of a second blowing agent having a boiling temperature at STP of less than 310 DEG K. The blowing agent combination has an equilibrium solubility vapor pressure in the polymer of less than 45 atm at the foaming temperature and greater than or equal to 1 atm at the glass transition temperature.
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