| 摘要 |
PURPOSE:To obtain a raw material of 100% mesophase capable of providing carbon yarn having high strength and high modulus of elasticity, by distilling petroleum pitch under reduced pressure, aging, separating by specific gravity and heat-treating. CONSTITUTION:Pitch produced as a by-product by thermal cracking of desulfurized vacuum oil gas is distilled under reduced pressure to give a fraction having cut 85%. A nonoxidizing gas is introduced to the fraction and heated to 380-430 deg.C while stirring to give pitch containing 5-15% mesophase. The pitch is aged at 300-350 deg.C, only mesophase is fused and separated into a lower layer containing the fused mesophase and an upper layer containing no mesophase by difference in specific gravity. 6-8C aliphatic hydrocarbons are extracted from the lower layer part to give 100% mesophase of raffinate.
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