Abstract: After adding different proportions of n-butane (HC-R600) to the mixed component foaming system of cyclopentane (CP) and HFC-245fa, the performance changes of rigid polyurethane foams prepared in a mold and the variation laws of thermal conductivity (k-factor) and compressive strength under two different aging conditions with different aging time were studied. Then compare the above variations of k-factor with the changes under the natural aging in a refrigerator. The research showed that the fluidity was improved and the k-factor increased with the increasing contents of blowing agent R600, while the compressive strength remained stable. During different aging processes, the results of k-factor were similar, and the changes in compressive strength were inconsistent, but there were acceleration relationship between them. The changes in k-factor of the refrigerator were significantly less than the changes in mold foams within the same aging time under different aging conditions.

Key words: Small molecule with low boiling point, R600, Polyurethane foam, Blowing agent, Foam performance, Aging performance