Coke production has become more expensive with the decreasing supply of caking coals, and the degree of technology required to manufacture high-quality coke from low-quality coal. Upgraded coals (called HyperCoal) from such low-rank coals can be produced by thermal extraction technology under mild condition; at temperature of 360 - 400℃, pressure of less than 4 MPa, without catalysts and hydrogen. HyperCoals have high thermoplasticity during heating; in particular, HyperCoals obtained from low-rank coals show high thermoplasticity beginning at temperatures near 150℃. On increasing the extraction temperature for sub-bituminous coal, the softening and the resolidification temperatures shifted to higher temperatures. Nuclear magnetic resonance measurements showed that the ratio of aromatic carbon increased with increasing extraction temperature, indicating that some modification reactions occurred. These results suggest that the HyperCoal obtained at higher temperatures contains more, relatively heavy components. The effects of blending these HyperCoals into standard coal blends were investigated. For coal blends made with the HyperCoal, produced from a sub-bituminous coal, increasing the extraction temperature from 360 to 400℃ increased the thermoplasticity significantly. Furthermore, the addition of 10% HyperCoal, extracted at 400℃, increased the tensile strength of the semicokes.%原油価格が100ドルを超える昨今のエネルギー高騰のrn状況の中，2008年の石炭価格も，発電用石炭が昨年度2.3rn倍の125ドル前後，また鉄鋼向け原料炭の価格に至ってrnは，年初豪州での豪雨による生産の減少と世界的な実需rnの拡大により，昨年に比べて3倍に引き上げられる見通rnしとなり，石炭も石油に続き本格的な“100ドル時代”にrn突入したと見られる。
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