Provided are a method for producing polycarbonates through melt transesterification, wherein is used a polymerization catalyst comprising a phosphorus-containing basic compound and a quaternary phosphonium salt having a specific structure; and a method for producing polycarbonates, which comprises pre-polymerization to prepare polycarbonate prepolymers followed by final polymerization of said prepolymers in a solid phase or in a swollen solid phase to produce the products, polycarbonates, and in which (1) a catalyst comprising a phosphorus-containing basic compound and a quaternary phosphonium salt having a specific structure is used in the pre-polymerization and in the final polymerization, or (2) a catalyst of a tri-valent or penta-valent phosphorus compound or a nitrogen-containing organic basic compound is used in the final polymerization, or (3) the final polymerization is effected in a vapor-phase atmosphere having an oxygen concentration of not larger than 2 ppm. In those methods, high-quality polycarbonates having good appearance, high heat resistance and high hydrolysis resistance are produced extremely efficiently.
COPOLYCARBONATE AND PROCESS FOR PRODUCING THE SAME
申请人:IDEMITSU PETROCHEMICAL CO., LTD.
公开号:EP1035150A1
公开(公告)日:2000-09-13
Provided are an aromatic polycarbonate copolymer and a method for producing it. An aromatic dihydroxy compound, at least one member selected from the group consisting of polyorganosiloxanes and aliphatic polyalcohols, and a dicarbonate are prepolymerized under heat to give a polycarbonate prepolymer, and the prepolymer is polymerized in a solid or swollen solid phase in the presence of a quaternary phosphonium salt serving as a catalyst to give an aromatic polycarbonate copolymer. The remaining monomer content, the acetone soluble content (that is, the low-molecular-weight substance content) and the cyclic oligomer content of the copolymer are all reduced, and the terminal hydroxyl fraction thereof is also reduced.
Disclosed are polycarbonates which are obtained by preparing a polycarbonate prepolymer through prepolymerization followed by polymerizing it through solid-phase, swollen solid-phase or thin film melt-phase transesterification, and have a remaining monomer content of smaller than 100 ppm, especially a dihydroxy compound content of smaller than 100 ppm, or have an acetone soluble content of at most 3.5 or at most 3.0 % by weight, or have a terminal hydroxyl fraction of smaller than 2 or smaller than 15 mol%; and optical materials and blow molding materials comprising the polycarbonate. The polycarbonates contain a reduced amount of impurities such as remaining monomers, oligomers and others and have improved physical properties including impact strength, and these are useful as optical materials and blow molding materials.
Polycarbonate Prepolymer for Solid Phase Polymerization and Process for Producing Polycarbonate
申请人:Ito Mitsunori
公开号:US20080064847A1
公开(公告)日:2008-03-13
A polycarbonate prepolymer for solid state polymerization, which is produced by an oxidative carbonylation reaction of an aromatic dihydroxy compound, a monohydric phenol having a boiling point of 330° C. or below, carbon monoxide and oxygen, the polycarbonate prepolymer being characterized by that (a) a ratio of aryl carbonate groups and hydroxyl groups each constituting terminal groups of the prepolymer is from 2:8 to 8:2, and (b) a molecular weight distribution (Mw/Mn) is from 1.1 to 2.1; and a process of producing polycarbonates including a step of solid state-polymerizing the prepolymer so as to increase the molecular weight thereof. According to the present invention, the prepolymer having a controlled molecular weight distribution suitable for solid state polymerization is provided, and a high quality polycarbonate is efficiently produced in environmentally friend manner.