A recording apparatus using full-line type ink jet recording heads needs a large amount of electrical power for ink ejection due to a large number of nozzles of the recording heads. B is O, NR13, NOR13 Or NNR14 R15; L is OH or NR14 R15; and X, R1, R2, R11, R12, R13, R14, R15 and J are as defined in the disclosure. Particularly, the use of dicyclopentadiene can give a hydrogenated product of ring-opened cyclic olefin polymer excellent in heat resistance, and this product can be advantageously used as parts or formed products for medical appliances or electrical components.