Samples of petroleum pitches were obtained from heavy pyrolysis resin and decant oil (heavy gas oil of catalytic cracking) by thermal polycondensation at atmospheric pressure, at temperatures of 380-400 and 410-440°С (for the resin and decant oil respectively), and with isothermal holding times of 30–480 min. Analysis of the dependence of the softening point on the mesophase content for the obtained samples showed that at the same mesophase content the pitches from decant oil exhibit a lower softening point compared with the pyrolysis resin pitches, for which the softening point approaches 300°C even with 30 % of mesophase. This suggests that it is impossible to obtain pitches from pyrolysis resin with a high mesophase content without preliminary preparation. On the other hand, it was shown that for pitches from decant oil it is possible to isolate up to 65% or more of the mesophase with a softening point not higher than 250°C.

石油沥青样品是在大气压下，在 380-400 和 410-440°С（分别用于树脂和倾析油）的温度下通过热缩聚从重热解树脂和倾析油（催化裂化的重瓦斯油）中获得的，等温保持时间为 30-480 分钟。对所得样品的软化点对中间相含量的依赖性分析表明，在相同的中间相含量下，倾析油沥青的软化点低于热解树脂沥青，软化点接近 300°C。含有 30% 的中间相。这表明在不预先制备的情况下，不可能从具有高中间相含量的热解树脂中获得沥青。另一方面，