| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a production method of a liquid crystalline polyester having low melt viscosity and low gas production amount, and liquid crystalline polyester excellent in fluidity and flexural modulus of elasticity.SOLUTION: A liquid crystalline polyester is composed of at least one of p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, and hydroquinone, and at least one of terephthalic acid and isophthalic acid. Derivatives such as acylation compounds of the p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, and hydroquinone can be used as an alternative, respectively. There is provided a production method of the liquid crystalline polyester, in which pressure reduction from a pressure in starting pressure reduction of 600-800 mmHg to a degree of vacuum of 100 mmHg is performed in 60-130 minutes at a temperature of the melting point of the liquid crystalline polyester or higher and (the melting point+50°C) or lower. The liquid crystalline polyester contains 40-70 md% of p-hydroxybenzoic acid.</p> |
