| 摘要 |
<p>A modified drying or semi-drying oil equivalent for use in the formulation of an alkyd resin system for the ink vehicle of a lithographic printing ink contains within its chemical structure linkages which are readily cleavable under mildly alkaline conditions. In particular the invention includes oil equivalents of formula I R1-X-(R3R4)Y-X-R2, wherein R1 and R2 comprise unsaturated aliphatic groups, especially ethylenically unsaturated C10-24 aliphatic groups e.g. linoleic residues; X comprises an alkali labile bridging group, preferably a sulphur, an acyloxy, a nitrogen or especially an oxygen bridging group; Y comprises silicon (Si) or titatium (Ti), and R3 and R4 comprise aliphatic, aromatic or araliphatic groups or groups of formula R1-X- or R2-X-, wherein R<S1>s, R2 and X are as previously defined. Preferred oil equivalents in which the R-X-substituents are amine or alcohol residues are prepared by ammonolysis or alcoholysis of the corresponding amine or alcohol with a suitable substituted silane or titanate precursor. The oil equivalent is incorporated e.g. from about 5 to about 50% by weight, in alkyd resin systems with typical alkyd polymer chain material, and the alkyd resin systems are blended e.g. up to about 10% by weight, in lithographic printing ink compositions with pigment and diluent. These ink composites advantageously exhibit improved de-inking properties as compared with prior art lithographic inks. </p> |
