Patent ID: 8067497
Filing Date: 2011-11-29
Classification: C08G,C08L

Abstract:
1. A method for the preparation of a flame retardant (FR) for engineering thermoplastic compositions, said FR containing less than 100 ppm of organic solvents with boiling point lower than 250° C. and increasing melt flow index of said compositions while minimizing corrosion of metallic parts being in contact with said compositions, said FR being a high molecular weight brominated expoxide (HMW BE) comprising a mixture of compounds of formula (I) and/or formula (II) and/or formula (III): wherein n is an integer; and wherein at least 80 mol % of the end groups of all three formulae in the mixture are tribromophenyl-oxo-2-hydroxypropyl groups, and at most 20 mol % of said end groups are glycidyl groups; said FR being characterized by a molecular weight of between 7,000 and 50,000 Daltons; and a free tribromophenol content less than 0.1 wt %; wherein said method comprises the steps of: a) preparing low molecular weight brominated epoxide (LMW BE) having a molecular weight of between 650 and 3,500 Daltons, and a content of organic solvents, with boiling point lower than 250° C., lower than 100 ppm of said LMW BE; and b) reacting said LMW BE with tetrabromobisphenol-A (TBBA), and with a component selected from the group consisting of tribromophenol (TBP), tribromophenylglycidyl ether and a mixture thereof, in the presence of a catalyst, wherein said reaction takes place without addition of any solvent, at a temperature of from 100° C. to 250° C., said method being characterized in that it does not include any step of removing the solvent from said high molecular weight brominated expoxide.