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TRANSPARENT ARTICLES PREPARED FROM THERMOPLASTIC COMPOSITIONS HAVING LOW BIREFRINGENCE

  • US 20110071261A1
  • Filed: 09/10/2010
  • Published: 03/24/2011
  • Est. Priority Date: 12/31/2008
  • Status: Active Grant
First Claim
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1. An optical grade article comprising a thermoplastic composition comprising a poly(aliphatic ester)-polycarbonate copolymer comprising the following monomeric units:

  • 10 to 25 wt % of a soft block ester unit derived from a C20-44 aliphatic dicarboxylic acid or derivative thereof, 34 to 77 wt % of a carbonate unit derived from 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine,0 to 76 wt % of a carbonate unit derived from a dihydroxyaromatic compound excluding 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, and wherein the sum of the weight percentages of soft block ester units, 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine units, and dihydroxyaromatic compound units is 100 weight percent of the monomeric units of the poly(aliphatic ester)-polycarbonate, andwherein the refractive index of the thermoplastic composition is greater than or equal to 1.590, and the glass transition temperature of the copolymer is from 120 to 155°

    C.

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