Styrene resin, styrene resin composition, molded article thereof, and styrene resin production method

A method for producing a styrene resin having a syndiotactic structure, comprising performing addition polymerization of one or more of a vinyl aromatic monomer in the presence of a catalyst containing a half metallocene transition metal compound (A) having at least one kind selected from metals of groups 3 to 5 of the periodic table and lanthanoid transition metals as a central metal, a compound (B) represented by the general formula (1), and a compound (C) selected from at least one kind of an oxygen-containing compound (c1) and a compound (c2) capable of forming an ionic complex through reaction with a transition metal compound,

• the styrene resin produced having a proportion of an endothermic amount obtained in a range of 175 to 260° C. of less than 30% based on the total endothermic amount taken as 100%, which are measured at a temperature rise rate of 20° C./min through differential scanning calorimetry:
• ((R1)3-Q-Y)k—Z—(R2)j-k (1)
• wherein R1 represents a halogen atom, an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, an aryloxy group having 6 to 30 carbon atoms, a thioalkoxy group having 1 to 30 carbon atoms, a thioaryloxy group having 6 to 30 carbon atoms, an amino group, an amide group, or a carboxy group, in which plural groups represented by 10 may be the same as or different from each other, and plural groups represented by 10 may be bonded to each other to form a ring structure depending on necessity;
• Q represents an element of group 14 of the periodic table;
• Y represents an element of group 16 of the periodic table;
• Z represents a metal element of groups 2 to 13 of the periodic table;
• R2 represents a hydrocarbon group;
• j represents an integer of a valence number of the metal element Z;
• and k represents an integer of 1 to (j−1).