| abstract |
The present invention relates to a thermally curable composition comprising: as component (a): (a1) 2.5% by mass or more of solid rubber, (a2) less than 5% by mass of rubber that is liquid at 22°C or a pasty ethylenic double bond-containing polymer, a hydrocarbon resin in which the sum of (a3) and component (a2) is 5% by mass or more and 20% by mass or less, and (a4) 15% by mass or more liquid polydiene, the above percentages are based on the total mass of the composition; and at least one selected from the following (b1) to (b3) as vulcanization system (b): (b1) Sulfur and one or more accelerators, (b2) a vulcanization system of peroxide type or disulfide type, and (b3) a quinone, quinonedioxime or dinitrosobenzene. |