| 摘要 |
Disclosed is an EPDM composition for molding sealing materials, containing a plasticizer; the plasticizer being a paraffinic oil or naphthenic oil in which the absolute value of the difference between its SP value (solubility parameter; determined by Small's formula) and the SP value of EPDM is 0.3 (cal/cm 3 ) 1/2 or less; and the composition being free of an ether ester plasticizer. The EPDM composition for molding sealing materials has the following excellent effects. Because a paraffinic oil or naphthenic oil that is compatible with EPDM and has an absolute value of the difference between its SP value and the SP value of EPDM of 0.3 (cal/cm 3 ) 1/2 or less is used as the plasticizer, a peroxide crosslinked product of the EPDM composition does not form defects that cause the starting point of blisters even when it is subjected to extraction by being brought into contact with HFO-1234yf. Accordingly, the peroxide crosslinked product, when used as a sealing material, particularly a compressor sealing material, exhibits excellent blister resistance to a hydrofluoroolefin refrigerant, such as HFO-1234yf. |
