| 摘要 |
<p>PURPOSE:To provide a printing ink resin excellent in solubility, by incorporating a rosin-modified phenolic resin having a particular solubility, prepd. by the reaction of a resol-type phenolic resin with rosin in the presence of an acid catalyst. CONSTITUTION:A printing ink resin which comprises a rosin-modified phenolic resin having such a solubility that no turbidity appears at 25 deg.C in a soln. of 25wt% or lower said rosin-modified phenolic resin in a 16C aliph. hydrocarbon solvent, said rosin-modified phenolic resin being prepd. by the reaction of a resol-type phenolic resin with rosin in the presence of an acid catalyst at a temp. of 150 deg.C or above to lower the acid value to 30 or below. Long-chain alkyl phenols such as octylphenol or nonylphenol pref. as the principal phenolic component of phenolic resins with respect to solubility. The softening point of rosin may be further increased by replacing the whole or part of the rosin by a polymerized rosin a part of which is subjected to dimerization.</p> |
