| 摘要 |
PROBLEM TO BE SOLVED: To realize the use as a binder for hot repair materials such as a spraying material by blending a novolak phenol resin and a resol phenol resin at a specified ratio. SOLUTION: The blending ratio is (95:5) to (50:50). Raw materials of a phenol resin used comprise phenols, such as phenol and bisphenol A, and aldehydes usually comprising formalin. An inorganic acid or an organic acid such as p-toluenesulfonic acid is used as an acid catalyst in reacting a novolak phenol resin. A metal salt such as zinc acetate, an alkali or an amine is used as a catalyst in reacting a resol phenol resin. The novolak phenol resin used has a solution viscosity of at least 150 μm<2> /s. The composition is preferably in a powdery form, having a minimum value of torque (at 130 deg.C) of 5 kg.cm and a time for reaching a torque of 200 kg.cm of 3-12 min as determined by Brabender Plastograph. |
