Patent ID: 7649062

Claim:
A solid titanium catalyst component (I), comprising titanium, magnesium, halogen, and a cyclic ester compound (a) represented by the following formula (1b): wherein n is an integer of 5 to 10; bonds between the carbon atoms in the cyclic backbone are all single bonds; a plurality of R 1 's are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms; a plurality of R's are each independently an atom or group selected from hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a nitrogen-containing group, an oxygen-containing group, a phosphorus-containing group, a halogen-containing group and a silicon-containing group, and they may be bonded to each other to form a ring, but at least one of R's is not a hydrogen atom; and a double bond may be contained in the backbone of the ring formed by the bonding of R's, and in the case where two C a 's are contained in the backbone of the ring, the backbone of the ring have 5 to 10 carbon atoms.