Neodymium-catalyzed conjugated diene-based polymer and rubber composition comprising same

A neodymium-catalyzed conjugated diene-based polymer satisfying the following conditions (a) to (c):

• (a) a residual amount of a neodymium catalyst, measured by inductively coupled plasma (ICP) is from 20 to less than 45 wtppm;
• (b) a β-value is less than 0.20, where the β-value is a slope of a log(frequency)(x-axis)−log(1/tan δ)(y-axis) graph obtained from measured results of tan δ at 100° C. by a rubber process analyzer (RPA);
• and
• (c) the following Equation 1 is satisfied:
• 0.3X+4<Y<0.3X+6 [Equation 1]
• in Equation 1,
• X is mooney viscosity (ML1+4, @100° C.), and
• Y is a ratio (%) of a number of polymer chains having a molecular weight of 1,000,000 g/mol or more based on a total number of polymer chains in a molecular weight distribution curve by gel permeation chromatography (GPC),
• wherein, in condition (c), X is 40 to 50.