Abstract:
In an embodiment, a melt polymerization process comprises melt polymerizing a carbonate compound and dihydroxy compound in the presence of a catalyst composition to form a polymerized polycarbonate, wherein the catalyst composition comprises an alkali catalyst and/or a quaternary catalyst; after a final polymerization, adding a chain scission agent to the polymerized polycarbonate to reduce a molecular weight of the polymerized polycarbonate to form a modified polycarbonate having a molecular weight that is less than the molecular weight of the polymerized polycarbonate.
Abstract:
본 발명의 연속식 고상중합 장치는 연속적으로 예비중합체를 투입하기 위한 피더; 상기 피더에 제1 연결부를 통해 연결되어, 상기 피더로부터 예비중합체를 수용하여 고상중합이 수행되며, 반응기 자체가 회전하는 횡형 반응기; 및 상기 횡형 반응기에 제2 연결부를 통해 연결되어, 횡형 반응기로부터 배출된 고상중합이 완료된 중합체를 수용하고 배출하기 위한 챔버;를 포함하며, 상기 횡형 반응기의 내벽에는 이형성 코팅막이 형성되고, 상기 피더, 상기 횡형 반응기, 및 상기 챔버는 진공 상태인 것을 특징으로 한다. 상기 연속식 고상중합 장치는 예비중합체의 정체 구간 형성을 방지하고, 불활성 가스 없이, 진공 상태에서 연속적으로 고상중합이 가능하다.
Abstract:
The present invention provides a reactor system for producing polycarbonate. The reactor system has one or more reactant vessels, an oligomerization reactor (203), a first pressure control device (211), a preheater (205), a second pressure control device (213), a distributor (209), and a flash tank (207). The one or more reactant vessels contain reactants contain a melt transesterification catalyst, a dihydroxy compound, and an activated diaryl carbonate. The reactor system is connected in the following configuration: (i) the one or more reactant vessels connected to the oligomerization reactor (203), (ii) the first pressure control device (211) disposed between and connecting the outlet of the oligomerization reactor and the inlet of the preheater; (iii) the second pressure control device (213) disposed between and connecting the outlet of the preheater and the distributor (209); and (iv) the distributor (209) disposed at the inlet to the flash tank. The pressure in the preheater is controllable at a pressure intermediate between the pressure in the oligomerization reactor and the flash tank.
Abstract:
Die Erfindung beschreibt ein Verfahren zur Herstellung von Polycarbonat nach dem Umesterungsverfahren wenigstens mit den folgenden Schritte: (a) Umsetzen wenigstens einer aromatischen Dihydroxyarylverbindung und eines Diarylcarbonats in der Schmelze wenigstens in Gegenwart eines Katalysators; (b) Vermischen der in Schritt (a) erhaltenen Schmelze mit einem Schäumungsmittel; (c) Entgasen der Schmelze aus (b) durch Einleiten der Schmelze über Eintrittsöffnungen in einen Abscheidebehälter. Das Verfahren ist dadurch gekennzeichnet, dass das Entgasen gemäß Schritt (c) unter Aufschäumen erfolgt, wobei die Schmelze über die Eintrittsöffnungen in Teilströme von 0,1 bis 20 kg/h aufgeteilt wird, die Temperatur beim Eintritt in die Eintrittsöffnungen 250 bis 340 °C und der Druck in dem Abscheidebehälter 0,1 bis 20 mbar beträgt.
Abstract:
Die Erfindung beschreibt ein Verfahren zur Isolierung von Polycarbonat, hergestellt nach dem Phasengrenzflächenverfahren, aus einer Lösung in einem organischen Lösungsmittel, umfassend die folgenden Schritte: (a) Verdampfen des organischen Lösungsmittels bis zu einem Gehalt an Polycarbonat von 90 bis 99,95 Gew.%, (b) gegebenenfalls Vermischen der in Schritt (a) erhaltenen Schmelze mit einem Schäumungsmittel, (c) Entgasen der aus (a) und gegebenenfalls (b) erhaltenen Schmelze durch Einleiten über Eintrittsöffnungen in einen Abscheidebehälter. Das Verfahren ist dadurch gekennzeichnet, dass bei dem Entgasen gemäß Schritt (b) die Schmelze über die Eintrittsöffnungen in Teilströme von 0,1 bis 20 kg/h aufgeteilt wird und beim Eintritt in die Eintrittsöffnungen eine Übersättigung mit flüchtigen Bestandteilen von mindestens 1 bar sowie eine Temperatur von 250 bis 340°C aufweist, wobei der Druck in dem Abscheidebehälter 0,1 bis 20 mbar beträgt.
Abstract:
In an exemplary embodiment, the method includes the steps of providing an array of reaction vessels and providing a plurality of homogenous reaction mixtures within the reaction vessels. Each mixture comprises monomers at least partially embodied in a liquid and is provided in an amount sufficient to form a film having a thickness sufficient to allow the reaction rate of the polymerization reaction to be essentially independent of mass transport. Polymerization then takes place in the presence of a catalyst at reaction conditions effective in substantially maintaining the homogeneity of the reaction mixture. In this manner, polymerization can take place quickly and efficiently without stirring the reactants. The method is highly useful for testing reactants, catalysts, and associated reaction parameters.
Abstract:
A process for preparing a polycarbonate by conducting transesterification in a reactor with the liquid-contacting portion thereof subjected to (1) heat treatment, (2) washing with a carbonyl compound, or (3) treatment with a particular hydroxyl compound; an apparatus for preparing a polycarbonate by transesterification, of which the liquid-contacting portion is made of stainless steel and the surface of the contacting portion is in a specific state; and a surface treatment method for providing the apparatus. Even in the case of a reactor made of inexpensive stainless steel, the surface treatment of the reactor in its liquid-contacting portion enables a high-molecular weight polycarbonate having a good color tone to be easily prepared by transesterification.