| 摘要 |
PURPOSE:A vulcanizable low-density rubber composition having improved physical properties, obtained by blending olefinic rubber with a crystalline polyolefin and a softening agent of a low aromatic mineral oil type to give a composition, blending it further with carbon black and a softening agent of mineral oil type. CONSTITUTION:[A] 100pts.wt. mixture consisting of (i) 100pts.wt. olefinic rubber (e.g., ethylene-propylene-nonconjugated polyethylene amorphous copolymer), (ii) 10-60pts.wt. crystalline polyolefin resin (e.g., monopolymer of copolymer of 1- olefin), and (iii) 10-100pts.wt. softening agent of mineral oil type (e.g., process oil) having <=0.950g/cc specific gravity D4<15> and <=30wt% aromatic composition content CA by ring analysis (n-d-M method) is blended with [B] 100pts.wt. carbon black and [C] 5-250pts.wt. softening agent of mineral oil type, to give the desired composition having <=1.09 specific gravity D4<15>. This composition has high spring hardness, high tensile strength, and high elongation ratio. |
