The purpose of this invention is to produce a stabilized terminal-blocked polycarbonate resin with a limited number of the terminal hydroxy groups having excellent thermal stability, color stability and hydrolysis resistance by an industrially advantageous method using a terminal blocking agent.
In the production of a polycarbonate by the melt-polycondensation of an aromatic dihydroxy compound with an aromatic carbonic acid diester in the presence of a polycondensation catalyst, a terminal blocking agent expressed by the following formula (1)
[in the formula, R1 is chlorine atom, methoxycarbonyl group or ethoxycarbonyl group; R2 is an alkyl group having a carbon number of 1 to 30, an alkoxy group having a carbon number of 1 to 30, an aryl group having a carbon number of 6 to 30 or an aryloxy group having a carbon number of 6-30] is added after the melt-polycondensation to the system in an amount of 0.3 to 4 mol-equivalent based on the hydroxy terminal group amount of the polycarbonate at 200 to 350°C under a pressure of 1,013 hPa (760 mmHg) or below for 0.1 second or longer and, thereafter, a stabilizer is added and kneaded into the system at 200 to 350°C under a pressure of 1.333 × 105 hPa (105 mmHg) or below for 0.1 second or longer.
The relative intensity of fluorescent light of a melt-polycondensed aromatic polycarbonate produced by the transesterification process (melt polymerization process) of an aromatic dihydroxy compound and a carbonic acid diester in the presence of a catalyst comprising a basic nitrogen compound and/or a basic phosphorus compound in combination with an alkali metal compound is suppressed to 4.0×10-3 or below at a wavelength of 465 nm based on a standard substance in a fluorescent light spectrum obtained by the excitation wavelength of 320 nm.
An aromatic polycarbonate having good color stability, especially good stability to the deterioration of the chip color during storage of the chip in air at room temperature can be produced by the present invention..
Process for preparing polycarbonate and apparatus for preparing polycarbonate
申请人:General Electric Company
公开号:US20030088051A1
公开(公告)日:2003-05-08
A process for preparing an end-capped polycarbonate comprises melt reacting an aromatic dihydroxy compound, a carbonic acid diester, and optionally a catalyst in a prepolymerization vessel to form a polycarbonate product; transferring the polycarbonate product from the prepolymerization vessel; mixing the polycarbonate product with an end-capping agent under hermetic seal at a pressure of at least about 760 mm Hg; and transferring the polycarbonate product and end-capping agent mixture to a postpolymerization vessel to endcap the polycarbonate product. An apparatus for preparing an end-capped polycarbonate comprises a prepolymerization vessel having and inlet and an outlet; a postpolymerization vessel having an inlet and an outlet; a mixer in fluid communication with the outlet of the prepolymerization vessel and the inlet of the postpolymerization vessel; and a charging port through which an end-capping agent is charged to the mixer, wherein the mixer is hermetically sealed at greater than or equal to 760 mm Hg.