Method for producing polycarbonate

A technology of polycarbonate and a manufacturing method, which is applied in the manufacturing field of polycarbonate and can solve problems such as hopeless hue and ineffectiveness

Active Publication Date: 2009-04-22
MITSUBISHI GAS CHEM CO INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is a problem that it is impossible to achieve a sufficient improvement in hue, and its stable effect cannot be achieved
[0006] In addition, JP-A-7-233253 discloses that sodium dithionite is used as an antioxidant to improve hue, but there is no description about the types of impurities in sodium dithionite and the influence of impurities on hue.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] (1) Adjustment of polycarbonate resin solution: Add 8.8% by weight of sodium hydroxide to a stirring tank with an inner volume of 100 L equipped with an AJITER type stirrer (manufactured by Shimazaki, triangular double blades, 135 cpm) 31 L of aqueous solution, 30 g of bisphenol A, 7 kg of bisphenol A, bisphenol A and sodium dithionite After dissolving, 11 L of dichloromethane was added, and while stirring with an AJITER type stirrer, 3.4 kg of phosgene was blown in over 30 minutes to perform a phosgenation reaction. After the phosgenation reaction is completed, stop stirring, and after standing and separating for 5 minutes, add a solution of 139 g of p-tert-butylphenol dissolved in 2 L of methylene chloride and 8.8% sodium hydroxide as terminal terminators to the reaction solution. 4 L of aqueous solution and 9 L of dichloromethane were stirred. After 5 minutes, 50 mL of triethylamine as a polymerization catalyst was added to the stirred reaction solution, followed by...

Embodiment 2

[0047] In addition to changing the sodium dithionite used in the above (1) to a washed and refined product (sodium formate content 0.1 wt%) made by BASF sodium dithionite (PF grade, sodium formate content 0.5 wt%) with methanol, and In the same manner as in Example 1, polycarbonate pellets were obtained. The polycarbonate pellets thus obtained were evaluated for hue in the same manner as in Example 1. The results are shown in Table 1.

Embodiment 3

[0049] In addition to changing the sodium dithionite used in the above (1) to a washed and refined product (sodium formate content 0.2 wt%) made by BASF sodium dithionite (PF grade, sodium formate content 0.5 wt%) with methanol, and In the same manner as in Example 1, polycarbonate pellets were obtained. The polycarbonate pellets obtained in this way were evaluated for hue in the same manner as in Example 1. The results are shown in Table 1.

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PUM

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Abstract

The invention relates to a preparation method of polycarbonate having good hues. The method is characterized in that, in the presence of organic solvents and sodium hydrosulfite, the content of formate in the hydrosulfite is below 0.3wt%, during the preparation of polycarbonate using bisphenol compounds and carbonyl chloride.

Description

technical field [0001] The present invention relates to a method for producing polycarbonate having excellent hue. Background technique [0002] Polycarbonate has excellent mechanical properties such as impact resistance and transparency, and is widely used in various fields such as mechanical parts, optical materials, automobile parts, and food packaging materials. [0003] However, since polycarbonate is easily colored when heated, coloration will occur depending on the heating history during molding processing or when the molded product is used. [0004] Therefore, many proposals have been made in the past, including adding an antioxidant to polycarbonate as a heat stabilizer, suppressing thermal decomposition during molding processing, etc. to improve hue, and adding a stabilizer. [0005] For example, JP-A-4-120164 discloses the addition of sulfur-containing carboxylic acid esters. However, there is a problem that it is impossible to achieve a sufficient improvement i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G64/24
Inventor 安永智和安藤和弘阿部久人小林敬典
Owner MITSUBISHI GAS CHEM CO INC
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