Polycarbonate compositions having improved chemical resistance, articles formed thereof, and methods of manufacture

A polycarbonate composition comprising:

• 75 to 99 wt % of one or more bisphenol A polycarbonate homopolymers based on the total weight of the polycarbonate composition;
• a poly(carbonate-siloxane) comprising a siloxane content of 35 wt % to 65 wt % based on the total weight of the poly(carbonate-siloxane) and comprising a weight average molecular weight of 32,000 to 45,000 Da, measured by gel permeation chromatography using a crosslinked styrene-divinyl benzene column, at a sample concentration of 1 milligram per milliliter, and as calibrated with bisphenol A polycarbonate standards, wherein the polycarbonate composition comprises 4 to 10 wt % siloxane content;
• and
• wherein a sample of the composition has improved chemical resistance as compared to a reference composition,
• wherein a molded sample of the polycarbonate composition has
• a tensile strength retention of 80% and higher after exposure of the bar for 168 hours to SANI-CLOTH AF3 at a temperature of 23° C. under 0.5% or 1% strain compared to a non-exposed molded sample of a reference composition tested at the same temperature, and
• a tensile elongation retention of 65% and higher after exposure of the bar for 168 hours to SANI-CLOTH AF3 at a temperature of 23° C. under 0.5% or 1% strain compared to a non-exposed molded sample of a reference composition tested at the same temperature,
• wherein the reference composition is the same as the polycarbonate composition, except that the reference composition comprises a reference poly(carbonate-siloxane) comprising a siloxane content of 20 wt %, based on the total weight of the reference poly(carbonate-siloxane).