Neutral static polycarbonates, methods of making, and articles formed therefrom

A method of preparing a polycarbonate composition, comprising:

• melt blending 1 to 75 wt % of a first polycarbonate prepared by interfacial polymerization and having hydroxy end groups, wherein greater than or equal to 97 mole percent of the hydroxy end groups are capped with an endcapping group, with
• 25 to 99 wt % of a second polycarbonate prepared by melt polymerization or interfacial polymerization and having hydroxy end groups, wherein 50 to 90 mole percent of the hydroxy end groups are capped with an endcapping group,
• wherein the wt % are based on the total weight of the first polycarbonate and the second polycarbonate;
• wherein 80 to 95 mole percent of the hydroxy end groups present in the polycarbonate composition are capped with an endcapping group;
• wherein an article having a thickness of 3.2 mm and molded from the polycarbonate composition has a haze of less than 3 according to ASTM D1003-00, and
• wherein a flat article molded from the polycarbonate composition has a surface charge of −2 to +2 kV.

A polycarbonate composition comprising:

• a first polycarbonate having hydroxy end groups, wherein greater than or equal to 97 mole percent of the hydroxy end groups are capped with an endcapping group, and
• a second polycarbonate having hydroxy end groups, wherein 50 to 90 mole percent of the hydroxy end groups are capped with an endcapping group;
• wherein 80 to 95 mole percent of the hydroxy end groups present in the polycarbonate composition are capped with an endcapping group;
• wherein each of the first polycarbonate and the second polycarbonate comprises repeating carbonate units derived from a bisphenol compound;
• wherein the polycarbonate composition has less than or equal to 0.001 wt % of residual bisphenol based on the total weight of the polycarbonate composition;
• wherein the polycarbonate composition does not include an antistatic agent;
• wherein an article having a thickness of 3.2 mm and molded from the polycarbonate composition has a haze of less than 3 according to ASTM D1003-00, and
• wherein a flat article molded from the polycarbonate composition has a surface charge of −2 to +2 kV.

A molded article for automotive headlight lens comprising a polycarbonate composition consisting essentially of:

• a first polycarbonate having hydroxy end groups, wherein greater than or equal to 97 mole percent of the hydroxy end groups are capped with an endcapping group, and
• a second polycarbonate having hydroxy end groups, wherein 50 to 90 mole percent of the hydroxy end groups are capped with an endcapping group;
• wherein 80 to 95 mole percent of the hydroxy end groups present in the polycarbonate composition are capped with an endcapping group;
• wherein each of the first polycarbonate and the second polycarbonate comprises repeating carbonate units derived from a bisphenol compound;
• wherein the polycarbonate composition has less than or equal to 0.001 wt % of residual bisphenol based on the total weight of the polycarbonate composition;
• wherein the polycarbonate composition does not include an antistatic agent;
• wherein an article having a thickness of 3.2 mm and molded from the polycarbonate composition has a haze of less than 3 according to ASTM D1003-00, and
• wherein a flat article molded from the polycarbonate composition has a surface charge of −2 to +2 kV.

A method of preparing a polycarbonate composition, comprising:

• melt blending a first polycarbonate wherein a flat article molded from the first polycarbonate has a measured surface charge of less than 0 kV, with
• a second polycarbonate wherein a flat article molded from the second polycarbonate has a measured surface charge of greater than 0 kV,
• wherein an article having a thickness of 3.2 mm and molded from the polycarbonate composition has a haze of less than 3 according to ASTM D1003-00, and
• wherein a flat article molded from the polycarbonate composition has a surface charge of −2 to +2 kV.

A method of preparing a polycarbonate composition, comprising:

• melt blending
• a first polycarbonate wherein a flat article molded from the first polycarbonate has a measured surface charge of less than 0 kV, with
• a second polycarbonate wherein a flat article molded from the second polycarbonate has a measured surface charge of greater than 0 kV, and
• an additive,
• measuring the surface charge of a flat article molded from the polycarbonate composition, and
• adjusting the proportion of the first and second polycarbonates as needed to provide a polycarbonate composition wherein a flat article molded from the polycarbonate composition has a surface charge of −2 to +2 kV.

A complex molded article comprising a polycarbonate composition comprising:

• a first polycarbonate wherein a flat article molded from the first polycarbonate has a measured surface charge of less than 0 kV, with
• a second polycarbonate wherein a flat article molded from the second polycarbonate has a measured surface charge of greater than 0 kV, and
• an additive,
• the complex molded article having a maximum positive surface charge (SCmax) of less than or equal to about +2 kV, and a minimum negative surface charge (SCmin) is greater than or equal to about −2 kV.