| 摘要 |
PROBLEM TO BE SOLVED: To reduce deteriorated substances and improve quality by using a Y-glove valve comprising a liquid contact part made of a material having corrosion resistance against a monohydroxy compound produced by reaction of an aromatic diol compound with a diester carbonate compound, which exhibits substantially zero leakage under a particular vacuum. SOLUTION: When a polycarbonate is prepared by polycondensation of an aromatic diol compound and a diester carbonate compound, a Y-glove valve in contact with a reaction mixture and installed halfway of a pipe of a manufacturing apparatus is made to exhibit substantially zero leakage under a vacuum of 40,000×10<-6> MPa or lower and a material having corrosion resistance against a hydroxy compound produced by reaction of the aromatic diol compound and the diester carbonate compound is used as a material constituting a liquid contact part. For the material having the corrosion resistance stellite is preferred as a seal part, and stainless steel such as SUS304, SUS316 or the like or carbon steel such as SS400, S25C or the like is preferred as a main body.
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