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A method for preparing polycarbonate by melt transesterification

A polycarbonate and polycondensation technology, applied in the field of transparent polycarbonate, can solve the problems of wide molecular weight distribution of polymers, difficult mass transfer, heat transfer, uneven catalyst distribution, etc., to achieve uniform molecular weight distribution, low reaction temperature, alkali Sexually Moderate Effects

Active Publication Date: 2016-03-16
JIANGSU OXIRANCHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

As the reaction progresses, the viscosity of the reaction system increases continuously, mass transfer and heat transfer become more and more difficult, resulting in local overheating, easy to produce branching, cross-linking and other side reactions, accompanied by variegated substances, affecting product quality ; In addition, the reaction is often uneven due to the uneven distribution of the catalyst, which makes the molecular weight distribution of the polymer wider and affects the performance of the product.

Method used

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  • A method for preparing polycarbonate by melt transesterification
  • A method for preparing polycarbonate by melt transesterification
  • A method for preparing polycarbonate by melt transesterification

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The reaction system consists of heating system, stirring system, condensation system and vacuum system. Carry out transesterification polycondensation reaction in 50ml three-neck bottle.

[0032] Weigh 43.2mmolBPA and 1.08 times DPC, add 2.5×10 -4 LiACAC of mol / molBPA (ACAC is acetylacetone C 5 h 8 o 2 Monovalent anion) aqueous solution (concentration is 4.323×10 -3 mole ml -1 ) as a catalyst, evacuate to a pressure of 4000Pa, and heat to 130°C within 5.0min. After the reactants are melted, start to stir. After 30 minutes of reaction, start to raise the temperature, rise to 160°C for 5 minutes, react for 20 minutes, then rise to 180°C for 5 minutes, react for 10 minutes, then reduce the pressure to 100Pa, rise to 220°C for 5 minutes, react for 5 minutes, and then The temperature was raised to 250°C in 5 minutes, reacted for 5 minutes, and then stopped the reaction.

[0033] The obtained product was subjected to the following determinations:

[0034] Viscosity av...

Embodiment 2-4

[0040] Under the same conditions, the experimental results of the alkali metal acetylacetone catalyst are listed in Table 1:

Embodiment 5-8

[0046] Under the same conditions, the experimental results of the lithium acetylacetonate catalyst of different consumptions are listed in Table 2:

[0047] The experimental result of table 2 different dosage lithium acetylacetonate catalyst

[0048]

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Abstract

A method of melt transesterification for preparing a polycarbonate, wherein an aromatic polycarbonate is synthesized through the two stages of transesterification and polycondensation under the effect of a coordination compound of alkali metal acetylacetonate serving as the catalyst, with aromatic dihydroxy compounds and aromatic carbonate diesters being the starting material. The amount of the catalyst used is 10-7 - 10-3 mol relative to each molar of the aromatic dihydroxy compound, the reaction temperature is between 100 and 250 °C, and the reaction process is performed in stages of progressively reduced pressure. The prepared polycarbonate product has a higher viscosity-average molecular weight, no color, and a lower viscosity-average molecular weight to number-average molecular weight ratio.

Description

technical field [0001] The invention relates to a method for preparing high molecular weight transparent polycarbonate by melt transesterification. Background technique [0002] Polycarbonate (PC) is a transparent resin with high strength, high toughness, high heat resistance, good shock resistance and processability, excellent shape and stability. It can be used alone or in blends and alloys. It can be divided into several categories such as aliphatic, cycloester, and aromatic. At present, bisphenol A PC is the most widely used. In the course of more than 50 years of development, the application field of PC has been continuously expanded. In recent years, due to the improvement of production technology and technology, PC materials have made faster progress in performance improvement and personalized design. The application of PC products has penetrated into construction, medicine, clothing, CDs, automotive materials, building materials, packaging Materials, broadband lig...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G64/30
CPCC08G64/307
Inventor 杨先贵张廷健王公应刘绍英王越
Owner JIANGSU OXIRANCHEM CO LTD
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