各種粘度指数向上剤添加油の高圧粘度特性とポリマー挙動の関係に関する研究（第2報）: 高圧粘度予測式の導出および圧力下の粘度-温度特性

摘要

本研究は粘度指数向上剤添加油（以下，Ⅶ添加油と記す）の高圧粘度特性と関係する溶存ポリマーの状態•挙動を明らかにすることを目的とする.第1報では，各種基油と化合物タイプおよび分子量の異なるポリマーからなる23種のⅦ添加油の高圧粘度を測定し，定義の異なる三つの圧力-粘度係数α_((Bl-obs)を決定するとともに，それらに基づきポリマーコィル自体の圧力-粘度係数α_(Pm)，基油の圧力-粘度係数α_(Bf-obs)およびポリマー添加量W_(pm) (wt%)からなるVII添加油の各圧力-粘度係数"α_(Bl-cal)予測式を導出した.%Using high-pressure viscosity measurements of 23 kinds of Ⅶ-blended oil reported in Part 1, a high-pressure viscosity prediction formula for Ⅶ-blended oil was derived. This equation is expressed in a so-called Barus formula, and the pressure-viscosity coefficient is the secant pressure-viscosity coefficient α_(B(p)-Bl) (=ln(η_(pt) / η_(ot))/P) in each ln(η_(pt))-P relation curve. The calculation formula of α_(B(p)-Bl) is composed of the corresponding base oil value α_(B(p)-Bf), the polymer coil itself pressure-viscosity coefficient α_(Pm) and the polymer concentration w_(Pm) (wt%). In relation to mentioned above, the volume fraction of one polymer molecule in hydrodynamically equivalent sphere, and the volume fraction of the hydrodynamic volume occupied in 100 cm~3 of Ⅶ-blended oil at critical concentration c* of polymer coil were investigated. It was also found that the viscosity index Ⅵ_(o-Bl) in the atmospheric pressure of the Ⅶ-blended oil drops with pressure. For this reason, the effect of temperature on the In(η_(pt))-P relation curve, the influence of polymer type and base oil in η_i-P-t relationship, and the influence of polymer type on atmospheric pressure viscosity η_(ot-t) relationship were discussed.