General Electric Company

Sabic Innovative Plastics IP B.v.

Gokul Srinivasan

Patrick Joseph McCloskey

Gautam Chatterjee

William David Richards

Warren William Reilly

Yatin Tayalia

Subash Scindia

Subarna Shyamroy

A method for producing a transparent article comprises the steps of melt transesterifying a monomer mixture in the presence of a transesterification catalyst to produce a hydroquinone polycarbonate copolymer product comprising greater than 45 mole percent of structural units derived from the hydroquinone. The monomer mixture comprises a hydroquinone, at least one aromatic dihydroxy compound other than the hydroquinone, and a carbonic acid diester. The hydroquinone polycarbonate copolymer product is then heated to a highest processing temperature of 5&#xb0; C. to 20&#xb0; C. above a maximum melting melt temperature for the hydroquinone copolymer product for a sufficient period of time to render the hydroquinone polycarbonate copolymer product transparent upon cooling to ambient temperature; and cooling the hydroquinone polycarbonate copolymer product to produce the transparent article. The method can also be used for producing transparent hydroquinone polycarbonate copolymers, which can be used for producing the transparent articles.

Methods for preparing transparent articles from hydroquinone polycarbonate copolymers

A method for producing a transparent article is provided. The method comprises melt transesterifying in the presence of a transesterification catalyst and a monomer mixture to produce a biphenol polycarbonate copolymer product comprising greater than 45 mole percent of structural units derived from the biphenol by heating the monomer mixture to a temperature of greater than 340&#xb0; C. to make the biphenol polycarbonate copolymer; and cooling the biphenol polycarbonate copolymer to produce the transparent article. The monomer mixture comprises the biphenol, at least one aromatic dihydroxy compound other than the biphenol, and an activated carbonic acid diester.

Methods for preparing transparent articles from biphenol polycarbonate copolymers

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Gokul Srinivasan