General Electric Company

Godavarthi S Varadarajan

James Alfred Day

Ganesh Kailasam

Bhaskar Bhairavnath Idage

Joseph A King, Jr

Swaminathan Sivaram

Gautam Chatterjee

Patrick Joseph McCloskey

Arun Savalaram Jadhav

Tomoaki Shimoda

Rein Mollerus Faber

Akio Kanezawa

Donald George LeGrand

Joseph Anthony King, Jr

Kenneth Michael Carroll

Satoru Minami

Vishnu Ramchandra Ranade

Christian Maria Emile Bailly

Nayaku Nivarati Chavan

Shamal Karunakaran Menon

Copolycarbonates containing such structural units as birefringence-reducing or &ldquo;soft block&rdquo; units are prepared by conducting a reaction, such as melt polymerization or equilibration, between a precursor polycarbonate and a monomer, polycarbonate oligomer or high molecular weight polycarbonate which is a source of other structural units. The crystallinity of the resulting precursor copolycarbonate or one of the reagents employed in its preparation is enhanced and the precursor copolycarbonate is subjected to solid state polymerization.

Copolycarbonate preparation by solid state polymerization

Polymerization of polycarbonates is performed by first enhancing the crystallinity of a precursor polycarbonate, such as an oligomer, by contact in pellet form with an alkanol in the liquid or vapor state as non-solvent, and then conducting solid state polymerization in a stream of inert gas such as nitrogen. The solid state polymerization operation includes a stage of heating at a constant temperature in the range of about 215-225&deg; C., optionally combined with a first heating stage at a constant temperature in the range of about 180-190&deg; C. The method is adaptable to continuous operation and produces a polycarbonate having a number average molecular weight, as determined by gel permeation chromatography relative to polystyrene, of at least 15,000.

Method for conducting solid state polymerization of polycarbonates

Solid state polymerization of polycarbonates and polyesters is preceded by a step of contacting particles of an amorphous precursor polymer with a particulate material, typically a crystallized polycarbonate, which prevents adherence of the precursor polymer particles to each other. It is then possible to perform the solid state polymerization step without crystallizing the precursor polymer.

Method for preparing polymers by solid state polymerization

Copolycarbonates containing such structural units as birefringence-reducing or 'soft block' units are prepared by conducting a reaction, such as melt polymerization or equilibration, between a precursor polycarbonate and a monomer, polycarbonate oligomer or high molecular weight polycarbonate which is a source of other structural units. The crystallinity of the resulting precursor copolycarbonate or one of the reagents employed in its preparation is enhanced and the precursor copolycarbonate is subjected to solid state polymerization.

Copolycarbonates comprise structural units derived from a bisphenol such as bisphenol A, a spiro(bis)indane bisphenol such as 6,6'-dihdyroxy-3,3,3',3'-tetramethyl-1,1'-spiro(bis)indane and a polyoxyalkylene glycol such as polyethylene glycol. These copolycarbonates have high processability and are expected to have low birefringence. They are useful for the fabrication of optical disks.

Optical quality copolycarbonates containing polyoxyalkylene carbonate

Polycarbonates are recycled without the need for chemical modification by dissolution in a solvent followed by removal of any insoluble materials and precipitation by addition of a non-solvent. The precipitation step may be followed by solid state polymerization of the recycled polycarbonate. Particularly when solid state polymerization is to be performed, the use of a combination of solvent and non-solvent which produces a crystalline intermediate is performed, and use of a modifying reagent increasing the hydroxy end group concentration of the polycarbonate may be advantageous.

Method for recycling aromatic polycarbonates

Crystallization of precursor polycarbonates prior to solid state polymerization is achieved by contact with a non-solvent comprising, at least in part, a dialkyl carbonate such as dimethyl carbonate. The non-solvent can be a mixture, typically of dimethyl carbonate with water or an alkanol such as methanol.

Method of preparing polycarbonates by solid state polymerization

A method for determining the effective level of catalyst for the preparation of a polycarbonate polymer by a transesterification reaction is disclosed. The method involves measurement of the leaving group by-product (usually phenol) produced in a test reaction between an aromatic dihydroxy compound and a carbonic acid diester, in the presence of a known amount of transesterification catalyst. The by-product production values can be compared with by-product reference values to calculate the effective level of catalyst. This data can be used to efficiently control catalytic activity in a production scale reaction for producing polycarbonate polymer.

Method for controlling the effective level of catalyst during the

Solid state polycarbonate formation comprises an initial step of converting a precursor polycarbonate to an enhanced crystallinity precursor polycarbonate and a second step of polymerizing said enhanced crystallinity precursor polycarbonate in the solid state. Several options are employed. These include modifying the precursor polycarbonate by contact with a dihydroxy compound or diaryl carbonate, conversion of the precursor polycarbonate to the enhanced crystallinity polymer by contact with at least one compound selected from the group consisting of alkali metal hydroxides, tetraalkylammonium hydroxides, tetraalkylammonium carboxylates, tetraalkylphosphonium hydroxides and tetraalkylphosphonium carboxylates, and conducting the solid state polymerization in the presence of a catalytic amount of at least one tetralkylammonium or tetraalkylphosphonium carboxylate. The preferred tetralkylammonium compounds are tetramethylammonium maleate and tetramethylammonium hydroxide. Polymerization may be conducted in the presence of a solvent resistance-imparting monomer such as hydroquinone or resorcinol or a branching agent such as 1,1,1-tris(4-hydroxyphenyl)ethane.

Method for preparing polycarbonate by solid state polymerization

A novel apparatus for isolating solids, slurries or wetcakes from fluids is disclosed. Said apparatus comprises an extruder having a dynamic seal and a barrel comprising a slip joint and a floating auger which allows for solid recovery under pressure in the absence of substantial solvent volatilization.

Extruder apparatus for separating solids from fluids

A novel apparatus for isolating solids, slurries or wetcakes from fluids is disclosed. Said novel apparatus comprises an extruder having a dynamic seal and a barrel comprising an auger and a movable cap which allows for solid recovery under pressure in the absence of substantial solvent volatilization.

Extruder apparatus for isolating solids from fluids

A novel apparatus for separating solids from fluids is closed to the atmosphere and comprises a spray feed inlet, a distributor cup and a heat exchanger and it allows for solid recovery under pressure without requiring substantial solvent volatilization.

Spray apparatus for separating solids from fluids

A novel apparatus for isolating solids or wetcakes from fluids is disclosed. Said apparatus is closed to the atmosphere and comprises a torque sensor and movable cap which allows for solid recovery under pressure without requiring substantial solvent volatilization.

Apparatus for isolating solids from fluids

A novel apparatus for isolating solids or wetcakes from fluids is disclosed. Said apparatus is closed to the atmosphere and comprises a slip joint and a floating auger which allows for solid recovery under pressure in the absence of substantial solvent volatilization.

Apparatus for separating solids from fluids

A process for isolating high bulk density polymer resins from polymer resin solutions is provided herein. More particularly, a polymer resin having a glass transition temperature of greater than about ambient temperature is isolated from a polymer resin solution by subjecting the polymer resin solution a gaseous component under moderate pressure and ambient temperature.

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Niskayuna, NY, United States of America

Godavarthi S Varadarajan