| 摘要 |
PROBLEM TO BE SOLVED: To provide a flame-retardant extrusion rubber composition having an excellent cost-performance ratio and having excellent flame retardancy and processability, and to provide a sealing material. SOLUTION: This flame-retardant extrusion rubber composition contains an ethylene-α-olefin-nonconjugate polyene copolymer and a halogen-based flame retardant. The copolymer, for example, has an ethylene/α-olefin ratio (in mol) of 40/60 to 95/5 and contains 0-25 wt.% of the nonconjugate polyene which has an intrinsic viscosity of 0.8-5.0 dl/g measured in xylene at 70 deg.C, a Q-value (ratio of a weight-average molecular weight to a number-average molecular weight) of 4-20 measured by gel permeation chromatography (GPC), and characteristic numbers of I and A (1) obtained from a molecular-weight distribution curve and satisfying: I>=2; and 1.5<=A (1)<=3.0 [I and A (1) are each defined in the specification]. A chlorine-based flame retardant or a bromine-based flame retardant is preferably used as the halogen-based flame retardant. A chlorinated paraffin and a chlorinated polyethylene are exemplified as the chlorine- based flame retardant. A brominated aromatic flame retardant, such as decabromodiphenyl oxide and octabromodiphenyl oxide, is exemplified as the bromine- based flame retardant.
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