WATER RELEASE TYPE INK COMPOSITION, PRINTED MATERIAL, MOLDING PRODUCT AND SEPARATION OF INK COMPOSITION COATING FILM

摘要

PROBLEM TO BE SOLVED: To obtain the subject ink composition capable of providing a printed material having excellent water resistance, if required, readily eliminating an ink coating film from a printed material in a water base by making the ink composition include a specific component in an ink composition. SOLUTION: This water release type ink composition contains a component which is substantially water insoluble or slightly water soluble and is made water-swellable or water-soluble by saponification treatment in an ink composition. The component is preferably a random, block or graft copolymer containing 35-95 wt.% of a lower alkyl ester of at least one kind of an unsaturated carboxylic acid selected from acrylic acid, itaconic acid, fumaric acid and maleic acid as a monomer unit. Preferably the content of the component is 10-95 wt.% based on the whole composition. A method for eliminating an ink coating film using the composition is carried out by saponifying a printed material with an acid or an alkali (preferably an alkali aqueous solution). Consequently a printed coating film is readily eliminated and a printed material can be recycled and used.