Thermoplastic Resin Composition Comprising a Phosphorus-Containing Compound in the Form of Polymer, Plastic Molded Article Molded From the Composition, and Method for Preparing a Phosphorus-Containing Compound in the Form of Polymer

A method for preparing a phosphorus-containing flame retardant compound in the form of a polymer comprising:

• reacting aryl group-substituted phosphonic acid dichloride with bisphenol-based compound represented by the following Chemical Formula 2 in the presence of a catalyst to polymerize polyphosphonate with unadjusted end groups;
• and
• reacting the polyphosphonate with unadjusted end groups with 4-cumylphenol to adjust the end groups and obtain a phosphorus-containing flame retardant compound in the form of a polymer represented by the following Chemical Formula 1:
• wherein A is a single bond, C1-C10 alkylene, C1-C10 alkylidene, C3-C12 cycloalkylidene, —S— or —SO2—, R is C6-C20 aryl or C1-C10 alkyl-substituted C6-C20 aryl, and n is an integer of 4 to 500;
• wherein A is a single bond, C1-C10 alkylene, C1-C10 alkylidene, C3-C12 cycloalkylidene, —S— or —SO2—.