General Electric Company

Andre Volkers

Marcel Puyn

Theodorus L Hoeks

Rein Mollerus Faber

Ralph Stevens

A process for quenching a catalyst used in the manufacture of polycarbonate by melt polycondensation of a dihydroxy compound and a diester. The process includes adding a quencher composition to an intermediate polycarbonate to deactivate residual catalyst. The quencher composition includes a compound having at least one sulfonic acid group and at least one amino group.

Process for preparing polycarbonate

A method for preparing polycarbonates by melt polycondensation of a dihydroxy compound and a diarylcarbonate compound in the presence of an alkaline catalyst is described. A branching quencher compound is added to an intermediate polycarbonate produced by the melt polycondensation reaction in an amount effective to inhibit or prevent the formation of branching species during a subsequent finishing process. Adding the branching quencher compound to the product of the melt polycondensation reaction produces finished polycarbonates with reduced branching species, high ductility and impact strength.

A process for quenching a catalyst used in the manufacture of polycarbonate by melt polycondensation of a dihydroxy compound and a diester. The process includes adding a sulfonic acid ester quencher to the polycarbonate and extruding the polycarbonate, wherein the amount of sulfonic acid ester added to the polycarbonate is effective to reduce the amount of branching species generated during extrusion of the polycarbonate to less than 100 parts per million. The catalyst used in the melt polycondensation reaction is selected from the group consisting of sodium dihydrogen phosphite, cesium dihydrogen phosphate and disodium magnesium ethylenediaminetetraacetic acid.

A laser markable thermoplastic composition which contains a copper phosphate salt such as copper phosphate, copper sulfate, cupric hydroxide phosphate and copper thiocyanate. The copper phosphate salt is preferably added in an amount ranging from about 0.1 to 5 parts by weight and the copper phosphate salt preferably has a particle size less than 10 .mu.m. The laser markable thermoplastic composition can be laser marked to provide a visibly distinct and separately identifiable region which preferably differs in overall color from the base material by a Delta E value of at least 10-20.

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Wouw, Netherlands

Andre Volkers