Olefin polymerization catalyst and method for producing olefin polymer

An olefin polymerization catalyst comprising:

• (I) a solid catalyst component for olefin polymerization containing at least magnesium, titanium, halogen, and an internal electron-donating compound,
• (II) an organoaluminum compound;
• and
• (III) an external electron-donating compound,
• wherein
• in the olefin polymerization catalyst, there exist, as the internal electron-donating compound, a first internal electron-donating compound and a second internal electron-donating compound;
• the first internal electron-donating compound being one or more compounds selected from a succinate diester compound, and the second internal electron-donating compound being one or more compounds selected from an internal electron-donating compound other than the succinate diester compound;
• and further comprises as the external electron-donating compound at least one or more compounds selected from alkoxysilane compounds represented by the following general formula (1):
• in the formula, R1, R2, R3, and R4, all of which are optionally identical or different from each other, represent a linear alkyl group having the carbon number of 1 to 8, or a branched alkyl group having the carbon number of 3 to 8, and
• one or more compounds selected from aminoalkoxysilane compounds represented by the following general formula (2):
• in the formula, r is 0 to 2, s is 1 to 3, and r+s is 1 to 3, R5, which optionally contains a heteroatom, represents any group selected from a linear or a branched alkyl group having the carbon number of 1 to 12, a substituted or an unsubstituted cycloalkyl group, a phenyl group, an allyl group, and an aralkyl group, R6 and R7, which are optionally identical or different from each other and optionally contain a heteroatom, represent a hydrogen atom or any group selected from a linear or a branched alkyl group having the carbon number of 1 to 12, a substituted or an unsubstituted cycloalkyl group, a phenyl group, an allyl group, and an aralkyl group, R6 and R7 are optionally combined to form a ring shape, and R6 and R7 are optionally identical or different from each other, R8, which optionally contains a heteroatom, represents any group selected from an alkyl group having the carbon number of 1 to 12, a cycloalkyl group, a phenyl group, a vinyl group, an allyl group, and an aralkyl group, and when R8 is plural, they are optionally identical or different from each other.