US 6,143,859 A · Copolycarbonate preparation by solid state polymerization

Abstract

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.

Claims26

Dependent claims

A method of copolycarbonate formation by solid state polymerization which method comprises:

(I) mixing a precursor polycarbonate (A) with a source (B) of additional structural units so as to form a precursor copolycarbonate;
said source of additional structural units (B) having structural features different from those of first precursor polycarbonate (A);
said precursor copolycarbonate having structural units made up of precursor polycarbonate (A) structural units and the structural units of source (B);
said mixing being carried out in a temperature range from about 170.degree. C. to about 250.degree. C.,
(II) converting the precursor copolycarbonate into a precursor copolycarbonate having enhanced crystallinity and
(III) subjecting said precursor copolycarbonate of enhanced crystallinity to solid state polymerization.

3 more elements

Dependencies are inferred from the claim text.

Copolycarbonate preparation by solid state polymerization

Life of this patent

Copolycarbonate preparation by solid state polymerization

Life of this patent

Abstract

Claims26