General Electric Company

Rensselaer Polytechnic Institute

Jerry C Lynch

Gary R Faler

E Bruce Nauman

John Robert Campbell

A method for separating polymers from a physically commingled solid mixture containing a plurality of polymers comprises dissolving a first one of the polymers in a solvent at a first lower temperature to form a first preferably single phase solution and a remaining solid component. The solid component contains additional polymers which are not soluble to the solvent at the first temperature but which may be soluble at higher temperatures. The method includes subsequently heating the solvent to dissolve additional polymer from the solid component to form subsequent solutions. The polymers are then separated from their respective solution either using flash evaporation techniques when more than one polymer has been dissolved at a single temperature, or conventional techniques for extracting a polymer from a solvent in a solution.

Polymer recycling by selective dissolution

A method for separating polymers from a physically commingled solid mixture containing a plurality of polymers comprises dissolving a first one of the polymers in a solvent at a first lower temperature to form a first preferably single phase solution and a remaining solid component. The solid component contains additional polymers which are not soluable to the solvent at the first temperature but which may be soluble at higher temperatures. The method includes subsequently heating the solvent to dissolve additional polymer from the solid component to form subsequent solutions. The polymers are then separated from their respective solution either using flash evaporation techniques when more than one polymer has been dissolved at a single temperature, or conventional techniques for extracting a polymer from a solvent in a solution.

Homo- and copolycarbonates of spirobiindane bisphenols are prepared by first reacting phosgene with a substantially pure spirobiindane bisphenol in the presence of aqueous base in a heterogeneous medium at a pH in the range of about 9-11, and subsequently adding an interfacial polycarbonate formation catalyst and, optionally, a dihydroxyaromatic compound and a chain termination agent and continuing phosgene passage at a pH of at least about 10. By this method, there may be prepared homo- and copolycarbonates of 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1-spiro(bis)indane having high molecular weight. Said homopolycarbonates and copolycarbonates with bisphenol A may be used for manufacture of optical disks having low birefrigence.

Method for preparing spirobiindane polycarbonates

Spirobiindane bisphenols of high purity, suitable for conversion to high molecular weight polycarbonates, are prepared by reacting a bisphenol or 4-isopropenylphenol with a metal halide Lewis acid or an alkanesulfonic acid, followed by removing impurities including phenols, 1-(4-hydroxyphenyl)indanols and the like. A step of purification by precipitation with water from a methanol-methylene chloride solution is included.

Substantially pure spirobiindane bisphenols and method for their

Spirobiindane bisphenols are prepared by contacting a mixture of a bisphenol or a 4-isopropenylphenol and a 1-(4-hydroxyphenyl)indanol with a metal halide Lewis acid or an alkanesulfonic acid. High purity spirobiindane bisphenols may be prepared by employing a purification sequence, which preferably includes a step of precipitation of the product with water from a methanol-methylene chloride solution.

Method for preparing spirobiindane bisphenols

An improved interfacial polycondensation polycarbonate process, the improvement comprising an initial equilibrated pH range of 11 to 13, a temperature range of 15.degree. to 40.degree. C., a carbonyl halide rate of addition of 0.03 to 0.3 moles per minute per mole of aromatic dihydroxy compound, and a chain stopper content of 0.02 to 0.05 moles per mole of aromatic dihydroxy compound. The resulting aromatic polycarbonate exhibits improved chemical and physical properties having a weight average molecular weight within a range of from about 25,000 to 65,000, and a monocarbonate content of less than about 400 parts per million.

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Scotia, NY, United States of America

Jerry C Lynch