Indene → Isopropenyltoluene indene

An autoclave equipped with stirrer vanes and having a real content of 1270 ml was continuously served with an isopropenyltoluene, an indene, a dehydrated and refined toluene and a boron trifluoride phenolate complex (phenol, 1.6 times equivalent) diluted 10-fold with the dehydrated and refined toluene at ratios as shown in Table 1, so that the total amount of the isopropenyltoluene and the indene was 1.0 l/hr, and the polymerization reaction was carried out at a reaction temperature of 0° C. The reaction mixture was then shifted to an autoclave of the second stage to continue the polymerization reaction at 0° C. when the total residence time in the autoclaves of the first and second stages reached two hours, the reaction mixture was continuously discharged, and the polymerization reaction was finished when three times of the residence time had passed. After the polymerization, a 1N NaOH aqueous solution was added to the reaction mixture to stop the polymerization reaction. The obtained reaction mixture was washed 5 times with large amounts of water. Then, the solvent and the unreacted monomer were distilled off in an evaporator under a reduced pressure to obtain an isopropenyltoluene/indene copolymer. The polymerization conditions (monomer feeding ratio, amount of catalyst, resin composition, yield) were as shown in Table 1. Properties (hue, softening point, molecular weight Mw, Tg) of the obtained isopropenyltoluene/indene copolymer resin were measured. The results were as shown in Table 2.